the problem of properties of short - term changes of solar activity has been considered extensively.   several periodicities were detected, but the periodicities about 155 days and from the interval of @xmath3 $ ] days ( @x math4 $ ] years ) are mentioned most often. in this paper   the problem of the existence of this periodicity for daily sunspot data from cycle 16 is considered. to determine the epochs of appearance of these periodicities  , the authors used the wavelet technique for the daily sunSpot areas between 1874 and 1993. during the same time period   they found a statistically significant periodicity in the frequency interval 57115 nhz ( 100200 days ) and for each of 10 time series.. the authors concluded that it presents around the maximum activity period in solar cycles 16 to 21. moreover, the power of thisperiodicity started growing at cycle 19, decreased in cycles 20 and 21 and disappered after cycle 21.
we investigate the detectability of circular polarization in the stochastic gravitational wave background ( sgwb ) by pulsar timing arrays ( ptas ).   we characterize the so called stokes parameters for monochromatic plane gravitational waves, and calculate generalized overlap reduction functions ( orfs ) so that we can probe the circular polarization of the sgWB. to do so, we formulate the cross - correlation formalism for anisotropic circularly polarized sgwbs with ptas. as a result  , we find that the orfs for the @xmath3 mode are consistent with the results of the previous work   . on the other hand, for the@xmath2 mode, the generalized orfs are not consistent with those of the previously published work  .we also discuss a method to separate the intensity ( @x maths3 mode ) and circular polarization ( @xiame2 mode ) of the Sgwb.
the tunneling through a potential barrier plays a very important role in the microscopic world and has been studied extensively since the birth of quantum mechanics.   one of the earliest applications of quantum tunneling is the explanation of @xmath0 decays in atomic nuclei. for most of the potential barriers, the penetrability can not be calculated analytically  @xcite. among those potentials for which analytical solutions can be obtained,   the parabolic approximation is the mostly used in the study of nuclear fusion. by approximating the coulomb barrier to a parabola  , wong derived an analytic expression for the fusion cross section @xcite which is widely adopted today in the research of heavy ion reactions. however, it is highly desirable to have an analytical expression when one introduces an energy - dependent one - dimensional potential barrier or barrier distribution functions. in the present work   we derive a new barrier penetration formula based on the wkb approximation. as a first attempt and a test study, we apply this new formula to evaluate @x Math0 decay half - lives of atomic nucleis.. the results show that the present analytical formula reproduces the experimental results very well, especially
we present a novel numerical time integration scheme for the hybrid monte carlo algorithm ( hmc ), which combines the idea of the force - gradient approach and the multirate approach.   we compare the behavior of the two methods currently used in the hmc algorithm, the nested force - gradients integrator @xcite and the adapted version introduced in @xmath0-body, and investigate the computational costs needed to perform numerical calculations, as well as the effort required to achieve a satisfactory acceptance rate during the evolution of the hmbc. using the schwinger model of quantum electrodynamics in two dimensions, we show that the new method is more efficient than the nested form of the forced - gradient integrator@xcite in terms of computational costs per trajectory and acceptance rate.
we propose essentially new methods for deriving functional equations for some one-, as well as two- loop integrals.   these methods are based on algebraic relations between propagators and they are suitable for derives functional equation for multi - loop integral systems. in the present paper   we describe in detail derivation of explicit relations for products of two, three and four propagators. also algebraic relation for product of arbitrary number of proparators is given.. these relations are used to obtain functional equations by means of generalized recurrence relations. from these relations   a new hypergeometric representation for the one - loop massless vertex type integral is obtained.
we propose and study the characteristics of a frequency hough procedure, designed mainly to reduce the discretization problem, and we compare it with the sky hough method, which is actually used in the virgo collaboration.   the paper is organized as follows : in sect.1 we present the basic scheme of the rome hierarchical procedure, based on the main idea of coincidences among subsets of data ; in sects.2, 3, 4 and 5 we discuss the limits due to digitization of the skyhough procedure ; in Sect.5, 6 and 7 we introduce the new frequency houghes procedure, discussing details its implementation and its basic characteristics ; in sectors.8, 9 and 10 we study the amplitude losses due todigitization, and thus efficiencies, for both the procedures.
the progenitors of core - collapse supernovae ( cc sn ) have been studied by examining images of the supernova ( sn ) sites taken prior to the explosion using either space - based optical detectors or ground - based infrared detectors equipped with laser guide star adaptive optics systems ( lgs - ao ).   about one dozen cc sn progenitor stars have been directly detected in pre - sn images, with roughly two dozen upper limits derived from non - detections. while most of this review focuses on the observational advances that have been made, theoretical input is critical to translate observed progeniting luminosity ( or limits ) into zero - age - main - sequence masses ( @xmath0 ) and stellar evolutionary states. among the most complete ( and accessiblestars. ] ) stellar evolution models at present are the metallicity - dependent models produced with the cambridge stellar evolution code, stars, since they follow stellar evolution up to the initiation of core neon burning, which is likely to give an accurate indication of the pre- and post - sn luminosity for each type of sn. as more and more nearby galaxies  hosts of future cc sns  have high - resolution images added to the
single - transverse spin asymmetries ( ssas ) play a fundamental role in the understanding of quantum chromodynamics ( qcd ) in high - energy hadronic scattering.   they are obtained by dividing the difference of the cross sections for the two settings of the transverse polarization by their sum, and are characterized by a large momentum scale @xmath1 and a much smaller, but also measured, transverse momentum@xmath2.. this is particularly interesting when the nucleon is transversely polarized, because there may be correlations between the nucleons spin vector, its momentum, and the parton s transverse momenta.    one such correlation, known as the " sivers effect " and described by so - called " sours functions ", is now widely believed to be involved in a variety of observed hadronic single - spin phenomena. among other things  , the observables may therefore provide valuable insights into the dependence of parton distributions in nucleons on transverse Momenta. here   we review the recent progress in the study of the sivers effects in qcd, with a particular focus on the recently established factorization theorems that allow to write the spin - dependent
kingman s coalescent is a random tree introduced by @xcite as the genealogy arising in large population genetic models.   it has infinitely many leaves and is usually constructed from leaves to the root as follows : given that there are @x Math7 lines in the tree, after some exponential time with rate @xmath8, two lines are chosen uniformly and merged to one line, leaving the tree with @x math9 lines. due to the quadratic rate @Xmath10 the tree immediately comes down from infinitely to finitely many leaves. since the seminal paper by@xcite this random tree has been generalized to other infinite trees arising in population genetics models. for the kingman coalescent some laws of large numbers and central limit theorems have been proved. here   we derive a full large deviation principle for the distributions of both the downwards and upward deviations of @x maths21. using the grtner - ellis theorem  , we show that the latter can be considered as a discrete graph, more precisely a discrete tree with infinitelyMany leaves.
the main purpose of this paper is to overview several different physical examples of multi - mode and/or multi - frequency solitary waves that occur for the pulse or beam propagation in nonlinear optical fibers and waveguides. for these purposes, we select three different cases : multi - wavelength solitary waves in bit - parallel - wavelength optical fiber links, multi - colour spatial solitons due to multistep cascading in optical waveguide with quadratic nonlinearities, and quasiperiodic Solitons in the fibonacci superlattices.   we believe these examples display both the diversity and richness of the multi - modes soliton systems, and they will allow further progress to be made in the study of nonlinear waves in multi - component nonintegrable physical models.
entanglement @xcite in a composite system refers to certain implicit correlation between the subsystems arising from their interaction.   it is the key resource of quantum computation and quantum information processing. despite many approaches to define entanglement for a bipartite system,   there have been only a few approaches to quantify entangler in the composite systems of three or more particles. in this paper  , we put forward a generalization of schmidt decomposition in multipartite systems in pure states using the ratio of norms of an entangling operator and of a disentangling operator in the relevant disentangled hilbert space as a measure of entanglements in the two - mode fock state and the squeezed state.    we show that the average von neumann entropies of the pure states of the decompositions of the components of the composite system can be defined in terms of the sum of the eigenvalues of the partial transposes of the reduced density matrices of the density operators of the composites under consideration. on the other hand, the concurrences of the pairs of subsystems are considered as the measures of concurrence of the subadditivity inequality.
slowly pulsating b - type supergiants ( spbsg ) have emerged as a new class of pulsating variables after saio et al.   ( 2006 ) have detected pulsational frequencies in the most satellite data of the blue supergiant hd 163899 ( b2 ib / ii, klare & neckel 1977, schmidt & carruthers 1996 ). because so far only one object of this type is found, the evolutionary status of these pulsators remains unrevealed. in this paper   we calculate models which undergo core helium burning on the blue loop and compare them with models in the hydrogen shell burning phase. for each model,   the effects of opacity, metallicity, overshooting, element diffusion and mass loss on the pulsational instability areas are studied. to identify the mode(s ) of the pulsators, we construct photometric diagnostic diagrams for the models and discuss a prospect for mode identification. an attempt to interpret the oscillation spectrum of hd163899   is presented.
domain walls ( dws ) between immiscible binary bose - einstein condensates in the tonks - girardeau ( tg ) state are studied by means of coupled gross - pitaevskii equations with the cubic - quintic repulsive nonlinearity.   the resulting equations are compared with the discrete nonlinear schrdinger equations ( nlses ), which have been used to model the tg gas of hard - core bosons in the one - dimensional ( 1d ) and quasi-1d states, respectively, using the quintic self - repulsion term.. the results show that the quadratic nature of the repulsive interactions between the two main components of the monte carlo gaseous gas is not affected by the steric distance from the center of the gas, but rather by the geometry of the ground state, which is determined by the inter - atomic repulsion strength of the system s fermions. for the first time, the quantum mechanical properties of the ternary tg phase are analyzed in the presence of the cubic ginzburg - landau term, which are found to be in good agreement with those of the quint
we use a modified flow analysis to identify inflation models where the perturbations at the end of inflation may be large enough for primordial black holes to be overproduced. for these models   we carry out a numerical evolution of the primordial perturbation and use the pbh constraints on the power spectrum to eliminate models which overproduce primordialBlackholes.   the results show that there are only a few inflation models which are compatible with all cosmological observations, for which the amplitude of the perturbed density is large enough to produce a significant density of primordial Black holes.
the sofia satellite observatory is a space - based observatory that monitors the Earth's surface with a high - resolution camera.   it is designed to be able to observe the earth from the air, and to plan its flights in real - time using an integrated flight management infrastructure ( fmi ) system.    the fmi product is intended to keep the aircraft from interfering with preplanned observations on the sky, and predicts the ground tracks necessary to execute its mission, and corrects the plan for actual conditions while airborne. here   we present a simulation of a simulated flight intended for april, 2008, from palmdale, ca. to support this, we have developed a new fmi application, called sampleflight, which uses data from the weather forecast and other sources to predict the plane's flight track and its constraints, and then compares the planned flight track to actual conditions in flight. as a result  , we show that the simulation can be used to test the feasibility of sofiancetwo - dimensional ( 2d ) flight planning and execution, including the ability to trade observations between flights, and perform replanning if conditions are sufficiently different from assumptions.
we have simulated 2-colour qcd, i.e. su(2 ) yang - mills theory with fermion matter fields ( ` quarks') in the fundamental representation of @xmath4, and finite@xmath0.   we use the hybrid molelcular - dynamics method and simulate the theory with 4 flavours of staggered quarks @xcite. at zero temperature,   the density of the quark - number and energy densities is about one third the mass of the nucleon, and the wilson line ( polyakov loop ) is about two orders of magnitude larger than that of the true qcd. for all the quarks except the diquark baryons, which are in the same multiplet as the pions, there is a non - negative determinant and a pfaffian. since the quantum mechanical properties of nuclear matter can be used to predict if and where strange matter could be produced at high temperatures, it is useful to study models which exhibit some of the properties of qcd at high @x Mathsomethings. here, we show that this theory is more similar to 2-flavour qcd than one might think.
the cooperative effects of the dipole - dipole interaction on the radiative behavior of atoms @xcite have been investigated numerically and analytically.   the experimental results are consistent with the theoretical results for two v systems with macroscopic light and dark periods, where the electron is essentially shelved for some time in a meta - stable state without photon emission. here   we investigate possible cooperative effects for two such four - level systems using two hg@xmath0 ions in a d configuration. for distances of about 15 wave lengths from the ground state,   these effects are of similar magnitude as for v systems, and for distances above this range the experimentally observed absence of cooperative effects is confirmed. however, for distances below this distance cooperative effects are found to be much smaller than for those for distances between 10 and 20 wave lengths, and this is explained by the fact that cooperative effects sensitively depend on how the meta-stable level is populated. for longer distances ( > 10 wave lengths )   cooperative effects appear to be more sensitively dependent on the number of levels in the system.
we give a combinatorial description of coloured quiver mutation in @xmath0-cluster categories.   we define a mutation operation on coloured quivers and show that it is compatible with mutation of tilting objects. for a positive integer @x Math0, it is natural to define a certain @x math1-calabi - yau orbit category of the derived category of a hereditary abelian category for which there are two arrows each of whose arrows has an associated colour@xmath4.. the arrows with colour 0 form the gabriel quiver of the tilting object. by using this definition, we show that the effect of an arbitrary sequence of mutations on a tiltingobject in an @x maths0-Cluster category can be calculated by a purely combinatorially based procedure.
we explore the phenomenology of the minimal supersymmetric model of low - energy supersymmetry with a continuous @xmath1 symmetry ( hereafter called the ` mr model')@xcite.   this model is a much smaller - dimensional extension of the standard model with a discrete @x Math3-parity ( mssm @xcite ) and is free of the superpotential term @x math4 and the soft supersuumetry breaking terms @x maths5 that cause well - known theoretical difficulties in the mssmsm. using the recent measurements of @xMath2, we find that the one - loop correction to @xmatrix@xmath2 is within the experimental value so long as the lighter top squark is light enough ( and the charged higgs boson is heavy enough ) and the charge on the charged - higgs / top / bottom vertex is high enough. by contrast, the oblique and qcd corrections to the @x mathematician9-quark and hadronic decay widths of the @Xmath10 each largely cancel when the ratio is formed, making @x mathematics2 very sensitive to direct corrections to #11 vertex  especially those involving the heavy
the optimal multiplication algorithm for integers is an open problem.   the classical method of adding two integers of @xmath1-bits takes @x math2 bit operations but the traditional method of multiplying them in @x maths3 bit operations requires @x Math3 multiplication operations. to perform efficient multiplication for small inputs, we use nikhilam sutra or method from vedic mathematics which is based on the fact that two - digit multiplication can be done with only three instead of four multiplications required by standard method. using this method,   we can perform large multiplication by converting it to small multiplication along with some addition and shifting operations. since multiplication operation is costly as compared to addition and shift, some constant number of addition and Shift operations   are required to perform the multiplication. here  , we propose a new algorithm for efficient multiplication of two @xMath3-bit integers by using nikhilam Sutra method.
the classical two - integral equilibrium theory in axisymmetric geometry is not sufficient to adequately describe the stellar discs of galaxies.   we have constructed new analytic three - integral component distribution functions that are two-integral but that can represent ( very ) thin discs when a judicious linear combination of them is chosen. by using a stckel potential, we show that these new components can be used as basis functions for the modeling of a van der kruit disc.
we study the time evolution of a quantum dot ( qd ) tunnel coupled to a single electronic reservoir.   we consider a voltage step pulse that affects the occupation of only a single orbital energy level. in an earlier work,@xcite some of the present authors investigated the decay of charge and spin of such a single level qd. since the reduced density matrix of a qd with a single orbitals with spin is four dimensional, there are thus three rates which govern the relaxation of the diagonal elements of the density matrix towards equilibrium ( plus one which is always zero and corresponds to the stable stationary state ). in addition to the rates that govern charge and spins, there is a third rate that appears in the Relaxation of a single - level Qd with spin and with interaction. here   this additional time scale is shown to be related to two - particle effects and appears, e.g., in the time - evolution of the mean squared deviations of the charge from its equilibrium value. by studying the dynamics of the system with the additional decay rate only  , we find that it is indeed related to 2-particle correlations. using a procedure to separately read out the different relaxation rates occurring in the dynamics
the b  z reaction is considered as a textbook example of chemical self - organization.   however, despite decades of intensive research, there are still ongoing controversies over the actual chemical kinetics and the mesoscopic dynamics ( i.e. exact nature and mechanism of patterns formation at the mesoscale ) of the reaction. here   we posit that our improved stochastic version of the wilensky netlogo model of the excitable medium@xcite can be used to explain the evolution of wave patterns together with the dynamics of spiral patterns. in order to numerically implement a hotchpotch model,   the model is limited to 200 achievable state levels and simulated on a square 50 @xmath0 50 grid. after a random setup of the space distribution of initial centers of @x Math1 $ ] as @x math2 where @x maths3 is the maximally achievable number of levels of the cell state, the model at each time step may proceed in four possible ways : ( 1 ) by using a low - level cellular automaton which can reasonably well account only for some of the observed b   z wave patterns, ( 2 ) by introducing a stochastically controlled rate of chemical reactions
ultra - high energy cosmic rays ( uhecrs ) are ubiquitous in the universe.   they are thought to be produced by a variety of sources, including neutron stars, active galactic nuclei, clusters of galaxies and plasmas. here   i discuss the use of ground - based atmospheric calorimetry to study the origin of these cosmic rays from the earth.. the results show that the source of the cosmic rays is likely to be an object with a magnetic field large enough to accelerate them to very high energies ( e.g. @xmath1 ev ) and a low density of proton - positron pairs ( e,g.@xmath2 ev ).    the rate of decay of the proton pairs is much lower than that of the neutrons and other sub - atomic particles, which means that there is a sharp reduction in the uhecr flux above the gzk cutoff for the maximum energy of the spectrum at @x math1 ev. erythrombosis of the protons and/or nuclei into the intergalactic medium may have been the cause of the observed changes in the spectrum.
the geometrical dynamics is a dynamics of elementary particles, generated by the space - time geometry.   the geometric dynamics is developed in the framework of the program of the further physics geometrization, declared in @xcite. as far as the classical dynamics is concerned, it coincides with the conventional classical dynamics, and it may be considered to be a generalization of classical dynamics onto more general space -Time geometries. however, the geometric dynamic has more fundamental basis, and its definition may be defined in multivariant space - times. understanding of nature of elementary particle is the aim of the Further Physics geometr - ization of physics. here  , we discuss the difference of aims of the two main geometriologies : the " physical " and the " chemical " ones.
microlensing is a powerful tool for the search for planets in our galaxy.   it is currently being used to detect planets around stars of the same mass as the sun, and has been shown to be particularly useful for binary star systems and planetary systems that are very similar to those of the sun.
the circular orbital velocity at the sun s radius in the milky way is of considerable interest in galactic and extragalactic astrophysics.   it is necessary to correct observed velocities of stars and galaxies for the motion of the sun around the galactic center, and it also plays a large role in characterizing the mass of the Milky way in comparison with other spiral galaxies. in this paper   we re - analyze the data from the very long baseline array ( vlba ) and the japanese vlbi  exploration of radio astronomy ( vera ) using a new population of tracers of milkyway dynamics : masers associated with star - forming regions ( *???   * r09 ). assuming a flat rotation curve, @xmath7 constant, we use a simple model for the distribution of the maser velocites with respect to their local standards of rest : a mean offset from circular rotation@xmath8 and a general velocity dispersion tensor fixed in galactocentric cylindrical coordinates.    our results show that allowing for a finite velocity dispersive tensor in the model for an inferred peculiar - velocity distribution function leads to lower values of
we have measured the basic _ isoscalar  double - pionic fusion process @xmath0 exclusively and kinematically complete.   the experiment was carried out with the wasa detector setup @xcite at cosy via the reaction @x Math19 using a polarized deuteron beam at the lab energy @xMath20 = 2.27 gev. since due to fermi motion of the nucleons in the beam deutron the quasifree reaction proceeds via a range of effective collision energies, we cover the energy region 2.30 gev@xmath21 2.47 gev for the emerging deuterons as well as the fast, quas ifree scattered spectator protons. from the full kinematic information available for each event also the relevant total energy in the @x math24 system   could be reconstructed for each individual event individually. by just having a different trigger these measurements   have been obtained in parallel to the ones for @x maths24 elastic scattering.
the initial mass function ( imf ) of very low mass stars is a fundamental aspect of the distribution by mass of newly formed stars, and it is of profound importance for an understanding of the mass content of the universe, the dynamical evolution of open and globular clusters, the chemical evolution of galaxies, and the physics of star formation. in this paper   we report deep hst observations of the stellar luminosity functions ( lfs ) in two open clusters with the refurbished hst.   the lfs show a broad maximum near @xmath5, while the underlying mass function breaks away from an approximate power - law increase below 0.5 m@xmath1. to study the effect of metallicity on the imf we find that the luminescence function of the cluster covers more than 2 dex in metallivity, and shows a strong dependence on the initial mass of the host star. at the same time, the luminosity function decreases linearly with increasing solar abundance, suggesting that the observed population of stars is not significantly different from that of the solar neighborhood down to masses near the hydrogen burning limit.
the mid - infrared instrument ( miri ) on the jwst spacecraft is an integral field unit ( ifu ) spectrometer that covers the wavelength range from 5 to 28.5 @xmath0 m at spectral resolving powers of a few thousand.   the instrument consists of 4 channels that have co - aligned fields of view, simultaneously observing the wavelength ranges listed in table 1 with individually optimised ifus, collimators and gratings. for the first time  , the miri has been used to measure the optical performance of the cryogenic material during cryogenic testing using a combination of high - resolution transmission electron microscopy ( tem ) and single - photon emission computed tomography ( spectc ). here   we describe the rationale for choosing the ifu concept and its impact on how observations are carried out as well as the expected on - orbit optical performances of the mri as measured by tem and spectc. also, we discuss the procedure used to construct calibrated spectral data cubes from the raw measured images.
the field of quantum chemistry has long pursued sophisticated nonlinear forms for its approximate wave function ansatzes.   recently, wave function stenciling, a generalization of gutzwiller s approach @xcite in which a nonlinear correlation factor removes unsuitable terms from an overabundant fermionic expansion, has been shown to be effective at capturing the full range of dynamic correlation effects when used as a guiding function for diffusion monte carlo ( dmc ) guided wave functions in strongly correlated regimes. however, the hilbert space jastrow factor is effective at making large changes to the wave function through stencils, but much less so at making the multitude of small changes demanded by dynamic correlation. here  , we present a new form of four - body jastrows that are better - suited to hide its curvature in regions of low wave function value ( where it will not affect kinetic energy ) and to count electrons within local regions of space ( the mechanism by which hilperturbative - triples can be used to achieve stenciled wave function effects ). combined with traditional two- and three - body Jastrows, a slater determinant, and diffusion
the direct and precise measurement of the self - coupling between the electroweak gauge bosons in @xmath2-pair production will be a crucial step in testing the standard model of electroweak interactions and searching for physics beyond it.   we propose a parametrisation of the couplings that simultaneously diagonalises certain matrices connected with our observables and with the integrated cross section, which is a combination of information from the total event rate and from observables that make use of the detailed distribution in the final state. using this method we show that the statistical errors on the different measured parameters are approximately uncorrelated.
we present four - dimensional ( 4d ) gauge theories that describe physics on 5d curved geometries.   taking generic values of gauge couplings and gauge - symmetry - breaking vacuum expectation values, the models provide vector, spinor, and scalar fields on curved extra dimensions. as a good and simple illustration  , we compare our 4d model with the randall - sundrum ( rs ) model. in particular, we particularly focus on the " localization " behaviors of mass eigenstates in " index spaces " of gauge groups. for massless vector fields,   hierarchical yukawa matrices are derived in our approach ; that is, a hierarchy without symmetries in four dimensions. to give a phenomenological application, we show that supersymmetry multiplets in flat 4d models generate supersymmetric multiplets on warped backgrounds.
the dwarf spheroidal ( dsph ) satellites of the milky way are ideal targets for the study of the formation and evolution of galaxies.   they contain a population of very old stars, and all of them exhibit low mean metallicities. here  , we use numerical simulations of chemical enrichment of dwarf galaxies in order to investigate whether this dearth of very metal poor stars ( vmpss ) is consistent with the simple hypothesis that the gas in the dwarf galaxies was completely self - enriched in metals ( i.e. that the metallicity when star formation started in these galaxies was essentially 0 ), and that the imf of these galaxies had always been given by a salpeter power law extending from 0.1 to 100 @xmath1).we find that the total mass of the dwarf galaxy sculptor ( hereafter, scl ) is relatively low, and its star formation rate is much lower than that of the other three dsophs. moreover, the stellar lifetimes of scl appear to have lasted only a few gyr, and after this initial period it appears to have stopped, as no stellar population younger than about 10 gyr has been detected : such a simple history should
the dynamical density  matrix renormalization group ( dmrg )  @xcite is a widely used method to compute the dynamical correlation functions and spectral functions of low - dimensional strongly correlated quantum systems.   the main drawback of ddmrg is that it always yields the convolution of the desired spectrum with a lorentzian distribution of finite width, which smooths out the sharp features of the true spectrum. in this paper   we present a method, which allows us to determine sharp spectral features in the thermodynamic limit starting from a broadened finite - system ddmrg spectrum. by applying a minimal distance between the deconvolved spectrum and the extrema of the inverse problem  , we can obtain a piecewise smooth spectrum of an infinite systems without the need for any regularization.
non - hermitian hamiltonians are often employed to describe the open systems due to their features of complex - valued energy and non - preserved particle probability.   recent observations show that a large families of non - hermits can have all eigenvalues real, if the loss and gain are set in a balanced manner under the combination of the parity ( @xmath1 ) and the time - reversal (@xmath2 ) symmetry. in this paper  , we investigate semi - infinite non -Hermitian system without @x Math0 symmetry. based on this, we try to clarify the concept of balance in the non - Hermitian discrete system in the framework of the quantum mechanics rather than a phenomenological description. here   we show an entirely real spectrum and study the exceptional point from the dynamical point of view.we show that the wave function within the lead becomes a unidirectional plane wave at the exceptional points.    this universal dynamical behavior is demonstrated as the self - sustained emission and reflectionless absorption of wave packets by two typical non - yourmitian clusters containing the complex on - site potential and non-hermitian hopping amplitude.
the vft thermal activation law of the glass transitions in bulk polymer systems is well obeyed experimentally.   however, there is no agreed upon theory of eq.( for the thermodynamic glass transition temperature ( vft ) which is a central experimental law which controls the rate of transition. here   we show that the vft law of transition rates can be derived from the following quantum mechanical considerations : ( i ) the nature of the excitations and ( ii ) the entropy of activation from the logarithm of the final state phase space magnitude. by contrast, the thermodynamically sinularity temperature of the thermodynamics glass transitions decreases as the ratio of boundary surface are to the bulk volume increases. on the other hand,   the singularity temperature at the activated energy singularity is sharply lowered when the density of final states is decreased to a few nanometers.. the difference between the thermal activation properties of open and closed strings is crucial for an understanding of surface effects which are of importance for thin films.
we present a theoretical investigation of polarization squeezing generated by an ensemble of x - like 4-level atoms illuminated by a linearly polarized field.   the system is described using collective operators for the n atoms of the ensemble, the optical dipoles being defined in the rotating frame associated to the laser frequency ( e.g., @xmath6 ) and the coupling constant between the atoms and the field is defined by the quantum heisenberg - langevin equations. we derive simple analytical criteria for the existence of elliptically polarized solutions and the stability of the linear polarization of the light @xcite and derive the stokes parameters of the vacuum field from those of the linearly polarized field. with these parameters, we show that both the linear polarized field mode and the orthogonal vacuum mode are squeezed when the incoming polarization is linear. at low frequency,   self - rotation is associated to strong atomic noise terms preventing vacuum squeezing ; on the other hand, saturation accounts for the squeezing on the mean field and crossed - kerr effect enables to retrieve vacuum squeezing at high frequency.
the tensor model was originally considered in @xcite to generalize the matrix model, which describes the two - dimensional simplicial quantum gravity, to higher dimensional cases.   this paper gives a summary of the results obtained so far concerning the emergence of the general relativity in the Tensor model.. the general relativistic properties of low - lying long - wavelength modes of small fluctuations around gaussian backgrounds in the tensor models that possess certain gaussian type of classical solutions are found to be in remarkable agreement with the general theory of relativity in all the dimensional cases having been studied so far.
the mystery of the dark energy / cosmological constant persists despite great efforts of particle physicists and cosmologists to find a convincing solution.   it is also an open question if both inflation and quintessence behavior can be explained by the same field and if not, what is their relation and which type of particle physics can provide both of them specially in a natural way. here   we suggest an alternative to a primordial quintessences field i.e. a decaying dark matter ( ddm ) that behaves like a quintessential matter when a very small fraction of the mass of primary ddm particles changes to a scalar field with proper self interaction potential. for this model,   the early time yield of this type of energy and its correlation with the amount of dark matter comes up naturally and the dominance of one with respect to the other at each epoch is automatically explained. as a result  , it is possible to obtain the present " equivalent " value of cosmologically relevant parameters without fine tuning of the suggested model.
the @xmath0@xcite is the first experimental data that can be used to study the dynamics of a family of heavy meson - doubly heavy baryons that could be interpreted as triply heavy pentaquarks.   this work is based on the assumption that these molecules are heavy hadronic molecules ( composed by a pair of heavy hadrons instead of a pairs of heavy quarks ). in this framework  , bound states will be found by solving the lippmann - schwinger equation as poles in the t - matrix : @x Math11, and the ultraviolet divergences of the loop function are treated introducing a gaussian regulator in the propagator and in the potential such as :   @x math12    = \frac{c_{b}^{\lambda}}{4}~ tr\left being the gell - mann matrices and @x maths6 the meson ( antimeson )
we introduce a new photometry procedure, called multi - aperture indexing, which is suited to analyzing well - sampled wide - field images of non - crowded fields with a highly varying point spread function ( psf ), such as those produced by large - aperture mosaic imagers on large telescopes.   we apply this procedure to archival imaging data from the mmt / megacam transit survey of the open cluster m37 ( hartman et al. 2008a ), demonstrating a substantial improvement over the existing photometry. in this paper  , we describe the development of our new methods for detecting systematic trends in time - series data and propose an efficient way for identifying, measuring, and removing spatio - temporal trends. using the newly defined contamination index and carefully tuned calibration procedures, we show that the results of the basic tests to validate our approach are very promising.
factorization of numbers into their prime factors is a hard non - polynomial problem for classical computers.   several approaches to factorize numbers based on interference of multiple quantum paths have been proposed. in the present paper   we investigate how truncated fourier sum and its generalizations, like truncated gauss, kummer and exponential sums, could emerge from superposition of several different oscillations. those sums can be used successfully to factorizing numbers.
we show that it is impossible to bound the sample complexity of any computable learning algorithm, even as a function of the target concept.   we show that there is an uncomputable learning procedure for which we bound the number of samples queried as a functions of the unknown target concept, independently of the distribution. in this paper, we discuss the implications of our results for computational learning theory.
in standard model ( sm ) the landau pole for a sufficiently heavy higgs boson mass is a function of the higgs quartic coupling.   it is well known that very quickly as the land au pole approaches the @xmath5 scale the landua pole becomes close to the weak scale and as a consequence the perturbative unitarity is broken in longitudinal gauge boson scattering amplitudes. at tree level and high energies   these amplitudes are purely@xmath9waves, proportional to higgs self - coupling. however in a series of recent papers it was shown how in the effective theory approach one can resum electroweak large double - logarithms from loops with su(2 ) and u(1 ) gauge bosons, which are part of standard model, and in this paper we study how such resummation affects the unitarity bound of sm by using the soft collinear effective theory ( scet ) approach. here   we extend the approach developed in @xcite@x Math13@xcite to include renormalization group improved amplitudes for sm including resumption of sudakov large double-logarithm corrections from loop contributions of su(
we report the first detection of  emission lines of atomic carbon ( c ) from protoplanetary disks around intermediate - mass stars using the atacama submillimeter telescope experiment ( aste ).   we performed  observations with the band 8 qualification model receiver mounted on the aste and measured the optical depth of the emission to derive the column density of c, and discuss possible evolutionary trends in the total mass of atomic c. the results show that the emission of c from the disk surface can be detected at 492.161 ghz and 461.041 ghz in the photon dominated region ( pdr ) of three classical t tauri stars ( ttss ) in taurus, lkca 15, l1551 irs 5, and hl tau, respectively. for the pdr,   the emission intensity of c@xmath10co @xmath3=43 is consistent with the theoretical predictions of the far - ultraviolet ( fuv ) photons that dissociate molecular hydrogen and carbon monoxide ( co ) and ionize c to yield ionized carbon ( ~11.6 ev ). because photoevaporation at the disk
in biological systems, chemical species with a small number of molecules may critically affect the behavior of the entire system.   we show that molecular discreteness can induce transitions to novel states in autocatalytic systems, which may affect macroscopic chemical concentrations @xcite. through stochastic simulations,   it is shown that such transitions can be induced by changing the concentration of some chemicals in the network.
white dwarfs are dense stellar remnants composed of electron degenerate cores surrounded by non - degenerate envelopes.   they are the end points of all low- to intermediate - mass stars, which are the majority of stars in the universe. as white dwarfs cool, they pass through instability strips depending on their outermost envelope composition, which coincides with the onset of a partial ionization zone, which drives periodic brightness variations of the white dwarf @xcite. here  , we describe the selection method of our new pulsating white dwarf candidates using colour - colour diagrams and present their spectroscopic observations.
the frequency of brown dwarfs in the substellar mass regime has remained a topic of confusion and debate.   we have used observations of seven nearby star clusters to constrain the combined low - mass brown dwarf initial mass function ( imf ). for all the regions, we consider the _ system _ imf, uncorrected for multiplicity within 200 au. for the young embedded clusters and the pleiades,   the imf is calculated using the ratio of stars ( 0.081.0 @xmath2 ) to brown dwarfts ( 0,030.08 @x math2 ).    the results show that the low-mass imf does not differ significantly between the two clusters, but there is a small variation in the distribution of the brown dwarf imf between the clusters. as the age of the clusters increases, the distributions of the lower - mass imf are more likely to be consistent with the theory of stellar evolution.
we investigate the curvature effect on spin polarization by considering two simple geometries : a simple linear conductor and a ring - like geometry which is formed by bending the chain.   the results are quite interesting. using a tight - binding framework and based on green s function formalism   we show that for a ring shaped conductor spin polarized currents are obtained in output leads of a multi - terminal geometry from a completely unpolarized beam of electrons, while absolute zero spin polarization is obtained for the linear conductor.
we present a partial p - representation of the total state of a composite quantum system, investigating a purely decohering qubit.   it enables us to make detailed, state and temperature dependent statements on the evolution of the correlations between system and environment, which we relate to the decoherence process. in particular, we investigate the influence of the environment on the decay of coherences of two qubits, and the effect of the initial state of the qubit on the nature of the ensuing system - environment correlations. for pure initial qubit states,   even a slight decrease of initial purity may have a significant effect on the fate of the resulting correlations. by means of the reduced density operator, we show that the rate of decoherent decay is time dependent, and can be described by the time dependent decay of the spectral density of the environmental density. at the same time, the coupling strength between the qu bit and each environmental mode of frequency is time independent. under certain conditions  , the correlation between the system and the environment is quantum mechanically correlated, which is confirmed by the presence of quantum reservoir entanglement.
the lab for adaptive optics ( lao ) currently has a testbed dedicated to the development of two key adaptive optics technologies for large telescopes ( multi - conjugate ao ( mcao ) and multi - object ao  ).   we are incorporating a high stroke mirror into the testbed both to eliminate the need for the spatial light modulators ( slms ) to phase wrap, and to test possible ao configurations for future systems called " woofer - tweeter" setups. in order to generate a flat shape we measured and inverted a kolmogorov wavefront and ran it through wooferfit to generate flattening commands.we have tested the suitability of the alpao dm52 as a woofer dm and have shown it has promising open - loop characteristics.
gamma - ray bursts ( grb ) are cosmological explosions which produce an enormous amount of energy @xmath2erg within a few seconds to a few minutes by means of a highly relativistic jet.   the spectrum is a continuum which is generally attributed to an optically thin synchrotron emission. in recent works, we have given particular attention to the individual grb pulses and obtained the timing and spectral informations. here   we review the results of our correlation studies and the possible improvements based on our new findings on the grb spectrum.
we study the rotation of protoneutron stars, under various conditions, using a standard model of dense matter, composed of nucleons and leptons.   we find that the maximum rotation frequency ( @xmath2 ) of prot one - photon - rich neutron stars is about 1.5 times higher than that of cold neutron stars, and that this difference is due to the existence of a phase transition in the central region of the star, which leads to the overshoot of the density at supranuclear densities. on the other hand,   the rotational frequency of uniformly rotating protoneUTron stars is much lower than that reported by takatsuka ( 1995 ), and is proportional to the mass and radius of the extremal _ static _ configuration with maximum allowable mass. for the first time, we show that these results are not based on an empirical formula, but on the calculations of the differential equations of state ( eos ) of hot, dense stellar interior, which have been recently published in the literature.
the fluctuation dissipation theorem ( fdt ) predicts how the response function of a thermodynamic observable is related to correlation of thermal fluctuations at equilibrium. in 1972  , g. s. agarwal obtained a modified fluctuation - dissipation relation ( mfdr ) that related response functions around non - equilibrium steady states ( ness ) to correlations evaluated at steady state. in this paper   we present a unified derivation of a number of mfds based entirely on the agarwalkian form of the fdt for a system evolving with a statistical dynamics characterized by the fokker - planck equation. using both the _ continuum _ langevin and  discrete  master equation dynamics, we show that the velocity excess from a local mean velocity can be expressed as a change in the entropy of the system.   this interpretation leads us to a modified einstein relation that has the same additive correction term for the two cases.    finally we apply this framework to a flashing ratchet model of molecular motors to calculate the mf dr and the additive correction in einstein relations, which shows a non - monotonic variation with the asymmetry parameter of the ratchet.
the polarization measure is an index of the distance of a distribution from the three cases of maximal polarization.   it has been used in economics for real distributions by, e.g. amari s natural gradient. here   we study the dynamics of this index, i.e. to characterise evolutions that maximise or minimise the index. using information geometry ( ig )  , we show that the polarization measure can be used to study the evolution of the gradient flow of a discrete distribution on the border of the probability simplex as a function of the polarised probability function. with the exception of the critical point at the uniform distribution, which is zero in the case of concentration in one class, and reaches its maximum 1/4 on distributions on two classes with equal probabilities,   the parameters of the curve are always in the range of 0.1 to 1.0.    we find that the magnitude of the polarization measures is proportional to the number of points in the curve that are in the region between the two classes where the probability functions are evenly distributed. when the curves are distributed on the borders of the simplex, the average of the points within the curve is close to the limit
we study frame decompositions of the space @xmath4 using translations of a family of functions on irregular grids, and arbitrary dilations, and we even replace dilations by other transformations.   our approach is different and very general, allowing quite general constructions.we prove the existence of smooth time - frequency frame atoms in several variables. for the case of irregular grids and unstructured dilations or if dilations are replaced by other Transformations the situation is more complex and requires different techniques. here   we use the regular case and try to obtain perturbations of the grid that preserve the frame structure. for wavelet frames on irregular lattices and with a set of dilations / transformations that do not have a group structure, we find necessary and sufficient conditions for a band limited function in order that it generates a smooth wavelet frame. for non - harmonic gabor frames with non - uniform covering of the euclidean space, we show that the same conditions can be found for the cases of wavelet sets associated with arbitrary families of invertible matrices and irregular sets of translates. for orthogonal wavelets, we give new constructions of waves with regular lattice translates.
summarythe cosmic microwave background ( cmb ) is a rich source of information about the early universe, from the star formation rate ( sfr ) history to the epoch of reionization ( eor ) at redshifts @xmath21, through the peak era at@xmath22, and down to the present epoch.   it has been suggested that the eor was complete at @x Math23, but this is not always the case. here  , we show that the cmb can be used to estimate the e or for a fully ionized intergalactic medium ( igm ), including both h and he, with an error bar of 68% in the marginalized cumulative distribution. using additional cosmological parameter constraints, we find that the optical depth of the igm is as low as @x math37 at 95% c.l.,1, and the sfr is as high as ~2.5 gyr ago. by combining the observed sfr and cmb data, we derive a reionizing epoch of @xMath0, which is consistent with our hypothesis that the galaxies and black holes observed today originated over 13 gyr earlier than previously thought.
kernel - pca is a technique that generalizes the well known principal component analysis ( pca ).   it is resulted in a low dimensional euclidean representation ( embedding ) of the data that approximates the feature space geometry. from a practical point of view, kernel methods have a significant computational drawback : spectral analysis of the kernel matrix becomes impractical for large datasets due to high computational complexity required to manipulate a kernel matrix and their global nature is also disadvantageous. here  , we introduce a general solution scheme that uses a multiscale interpolation scheme to solve the aforementioned limitations. using the proposed approach,   we show that the performance of the proposed method is comparable to that of the most popular out - of - sample extension method, geometric harmonics ( gh ).
the chiral phase transition of the qcd phase diagram at finite temperature and density is studied using a composite operator formalism.   the analysis is based on a landau expansion of the effective potential around the critical temperature for the chiral transition, @xmath3, where the thermally averaged quark - antiquark bilinears are the typical order parameters for chiral symmetry transition. in the case of light massive quarks, such as the scalar and pseudoscalar ones, the current quark mass plays a role analogous to that of an external magnetic field in the ferromagnetic transition, as it explicitly violates the chirality whose restoration characterizes the phase transition.
we discuss the relation between zero - frequency current noise, coulomb correlations, and entanglement for the example of a double quantum dot.   we make use of the recent observation that noise measurements in the nonlinear coulombs - blockade regime can be used to obtain spectroscopic information of excited levels in a quantum dot using the fano factor ( i.e., the ratio of noise power to current ) as a measure of the interaction parameter @xmath0 from experimentally observable quantities. here  , we extend this work by analyzing the full counting statistics of the transferred charge in a double - dot system by means of an analysis of the total number of electron tunneling events through the excited two - electron states which result in super - poissonian shot noise characterized by a Fano factor.    this kind of noise spectroscopy can be applied to directly extract the interaction parameters @x Math0 and@xmath1 from experimentically observable quantities such as the signal - to - noise ratio.
the generalized second law of thermodynamics ( the gsl ) is a generalization of the second law, holding in the presence of black holes, to the problem of ideal fluid flow.   we use this generalization to show that the correlation length of a real fluid can not be arbitrarily small and that the energy - momentum tensors describing systems which display macroscopic fluid behavior must be subject to a restriction : the shear viscosity, a function of the thermodynamic state of the system, cannot be arbitrary small.
we report on molecular line mapping of the nessie nebula, a filamentary infrared dark cloud ( irdc ) located near @xmath8 in the mid - ir region of the australia telescope national facility ( atnf ) 22 m mopra telescope.   we find that the nebula contains a number of long, approximately cylindrical molecular lines, which are consistent with the theory of self - gravitating fluid cylinders and show that the observations broadly conform to the expectations of the " sausage " or  varicose " fluid instability. using this theory, we propose that the formation of dense molecular cores within filamentary irdcs may result from the passage of a spiral shock, which leads to the fragmentation of the gas and dust surrounding the core into filaments, which then coalesce into clusters and high - mass stars.
the fractional quantum hall effect@xcite ( fqhe ) in graphene is explored by a combination of exact diagonalization and the cf theory.   we show that the su(4 ) symmetry is spontaneously broken at @xmath23, i.e., the orbital part of the ground state is antisymmetric and the excitations are skyrmionic. for other states,   the energy spectrum of the problem matches with that of the su problem, although the multiplicities are vastly different.
abstractthe distribution of interstellar matter ( ism ) within the disks of spiral galaxies is a fundamental feature of galaxy evolution.   recent observations of the hi line and the co  @xmath9 line have shown that the density of atomic gas column density in the disk of our galaxy is roughly constant, with @x Math14 being the " standard " value. here   we show that this is not always the case, as the surface density of the molecular gas column has a non - linear slope from the inner disk to the galactocentric radius of the giant molecular cloud @xcite, which is at odds with the model of a constant gas depletion time given by @x math14. using data from the x - ray absorption spectroscopy experiments of the high - energy x - factor ( hi ) and the cosmological survey of the universe ( co ) lines, we find that the rate of star formation rates on the large ( i.e., galactic ) scales is much slower than that on the small scale. for the first time  , we demonstrate that these results are consistent with the schmidt - kennicutt law, which states that star formation rate surface density is related
non - commutative field theories deserve a thorough and systematic investigation, not only because they may be relevant for physics beyond the standard model, but also because they can describe effective physics in our ordinary standard world but with non - local interactions.   we provide a new proof that the grosse - wulkenhaar scalar @xmath4 theory on the moyal space is renormalisable to all orders in perturbation theory using a multiscale analysis analogous to @xcite but in direct space.
the cytoskeletal motors are enzymes which catalyze the hydrolysis of adenosinetriphosphate ( atp ) and, at the same time, use the free energy released from this reaction to perform mechanical work and convert it into directed movements.   these motor molecules have been studied extensively during the last decade, both experimentally and theoretically. in order to study these random walks, we have recently introduced a class of lattice models, which are, on the one hand, generic in the sense that they are independent of the specific motor mechanisms, but which we can also apply to describe specific motor molecules by adapting the model parameters to the observed transport properties. in addition, we can easily incorporate motor  motor interactions such as the mutual exclusion from binding sites of the filaments, which leads to traffic jam-like density pattern and various kinds of phase transitions. in the following, we will review our results for the motor s random walks obtained from these lattices and present some new analytical results from the corresponding continuum equations.
quantum mechanics is a powerful tool for the study of quantum phenomena.   it is well known that, if backward time travel could be implemented, or if the present could shape the past by some other means, then closed causal chains, or causal loops, could be formed. if these loops are not self consistent, paradoxes arise. in this paper   we show that quantum mechanics may provide an answer to this question. using the probability operator measure ( pom )  , we find that the probability for the measurement outcome of a measurement is always zero if the system is prepared in a state that is not necessarily the state it is found in at the time of measurement. upon measurement   there is a discontinuous change, or collapse, of the state to that corresponding to the pom element associated with the particular measurement outcome. on the other hand, if the preparation and measurement events are self - consistent, the probability of the measurement event being the same as that of the preparation event is 0.5 times higher than those of the pre - measurement event. when the two events are independent of each other, such that the measurement results are determined by the state the system was prepared in, the probabilities for the
the photo - assisted shot noise of a one dimensional correlated quantum hall bar in the fractional hall regime is studied using a semi - classical approach.   the effect of a localized time dependent perturbation on the conductance of the system is investigated by applying voltage gates on which the field of view is biased in the andreev regime. for non - interacting electrons, it has been shown that the noise derivative with respect to the bias exhibits evenly spaced steps whose height is specified by bessel functions. here  , we show that this behavior is not always the case, as the step like behavior of non interacting electrons will be strongly modified when the system has a strong backscattering background. at the same time, the current response of the conductor is modulated by the presence of a dc bias, which acts as a probe to retrieve information on the finite frequency noise spectrum.
the peculiar velocity field of galaxies induces a significant systematic effect in statistics of observed galaxy distributions in redshift space, especially on scales below @xmath0mpc.   the proper account of this redshift - space distortion requires a detailed model for the pairwise velocity distribution function ( pvdf ) of galaxies. in the present paper  , we attempt to improve the sheth ( 1996 ) model of the origin of the exponential form of the pv df of dark matter by adopting a series of more realistic density profiles for dark halos and by incorporating the scale- and mass - dependence of the peculiar velocity dispersion ( pvd ) directly from the abel integral of the density profiles. using the selection function following jing, brner & suto ( 2002 ), we also phenomenologically attempt to predict the pvd of _ galaxies _ out of that ofdark matter particles using the press  schechter formalism.
the einstein universe is a particular case of, and conformal to, the closed friedmann - lematre - robertson - walker ( flrw ) models, where the assumption of staticity is relaxed by introducing a scale factor that allows the universe to expand or contract.   it is natural to look for solutions of the maxwell equations whose electric and magnetic fields, as measured by the static observers, are aligned with these fibres. in this work  , we find a remarkable solution of maxwell s equations in the einstein Universe, which will then be interpreted as a knotted, finite energy, radiating electromagnetic field in minkowski s spacetime. using this solution,   we show that the cosmological constant of the e Einstein universe can be reduced to a power of the scale factor, and that the energy of the electromagnetic configuration can be modelled as a function of the spatial volume of the universe. finally, the matter distribution that must be added to obtain a self - consistent solution of the Einstein - maxwell equation will be determined.
the thermomechanical behaviour of a shape memory alloys ( sma ), with a particular focus on the rate - dependent response and on the influence of thermal conduction and heat transfer in the mechanical behaviour, is studied by means of a numerical study.   the model is presented both in a three - dimensional and a monodimensional setting ; the reduction to this latter case is still meaningful because in most engineering applications shape memory alloy wires are employed. as a result, the model comprises a macroscale model comprising an internal variable to quantify the extent of the phase transition between austenite and the martensite variants and a time - dependent ginzburg - landau  equation which describes the thermo - mechanical interactions which strongly influence the constitutive behavior of a sma and to account for non - isothermal conditions. at the same time, it is also shown that the temperature - dependent behaviour of the sma is influenced by the effect of heat transfer and of the heat dissipation towards the ambient.
we study surfaces in space @xmath0 such that through each point of the surface one can draw two circles fully contained in the surface.   we reduce finding all such surfaces to the algebraic problem of finding all pythagorean@xmath1-tuples of polynomials.
bigravity is a theory of gravity with two independent dynamical metrics.   the main goal of this paper is to study the properties of black hole solutions to the action (  ) in which the action is an interaction potential and the newton s constant is a dimensionless parameter. for some recent work   see @xcite, we have replaced the interaction potential with a more general potential ( with two parameters ) and show that regular solutions do exist. here   we also compute the total energy, entropy, temperature and thermodynamical properties of these solutions.    we discuss the applications of bigravity to massive gravity.
supergiant fast x@xmath0ray transients ( sfxts ) are transient x - ray sources associated to o or b supergiant stars and characterized by short outbursts.   they typically last a few days and are composed of many short flares with duration of a few hours. in this article   we review the current knowledge on the mechanism of the sfcts, focusing on the role of the equatorial wind in the formation of the flare activity and the possible coexistence of clumps of matter from the companion wind.
abstractthe formation of multiple populations in globular clusters ( gcs ) is a major challenge in the field of stellar biology.   the process by which enriched material is incorporated into stars will dictate the initial configuration of the enriched ( i.e. polluted ) stars compared to the primordial ( i,e. normal ) stars, and this will set the initial conditions for the long - term dynamical evolution of the cluster and its multiple populations. because gcs are collisional systems, they are expected to form multiple populations with different initial phase - space distributions, which will eventually mix and segregate into distinct subpopulations. here  , we review constraints on the formation of these multiple populations imposed by their present - day kinematics and spatial distribution and discuss how these constraints can be used to explain the observed chemical abundance anomalies in the colour - magnitude diagrams of gcs.
we explore the possibility that recent results regarding the mass profiles of clusters of galaxies obtained by gravitational lensing @xcite might be explained by the degeneracy pressure of light fermionic dark matter particles. using a phenomenological equation of state that describes the physical conditions between fully degenerate fermion gas and the classical ideal gas, we integrate the equation of hydrostatic equilibrium, under the simple assumption that the local kinetic energy of a classical particle is equal to its gravitational energy determined by the 3d encircled mass.   our model is expected to be valid only near the core of a cluster where dynamical equilibrium can be achieved. as a case study  , we apply our modeling to the cluster of galaxies a1689 and constrain the possible combinations of particle properties. for pure fermions,   the volume density profile is uniquely determined by three parameters, the central density, @xmath0, and the properties of black matter particles, namely, the mass,@xmath1, and statistical weight, @Xmath2. to compare our model with observations, we smoothly connect our model volume density Profile describing the inner region to a volume density profiling derived from the observed column density profile by assuming spherical symmetry
abstractthe most recent observational results in the field of magnetic maps obtained by indirect tomographic imaging from sets of rotationally modulated spectropolarimetric data are particularly intriguing and thus potentially very fruitful for providing new clues to what may be happening in the convective layers of fully convective stars.   these results suggest that dynamos operating in very active stars are likely to be significantly different than that of the sun, and that such dynamos are able to produce large scale field ( and especially toroidal field ) very close to the surface, and presumably even throughout the whole convective zone, rather than being confined at its base as in the sun. however, this conclusion raises a number of problems ; we can no longer understand, for instance, how the magnetic field can be stored within the convection zone for periods of time as long as decades, and how it can be used to generate the plethora of active phenomena observed both at their surface and in their immediate surrounding. if applegate s ( 1992 ) idea is true, it therefore implies that very active Stars such as those found in close binary systems, but also young single stars that did not dissipate most of their angular momentum yet and still exhibit very energetic active phenomena
the existence and uniqueness of solutions to the differential equations of physics is seldom an issue.   the very fact that these equations describe physical reality seems to argue that their solutions must exist and be unique. in this paper   i argue that turbulence is a system of differential equations that has a fragile limiting case, in which uniqueness fails for _ every _ solution at _ every_ time. as a limiting case  , the burgers equation is a problem in which the solution of the inviscid burgers equation may develop discontinuities ( " shocks " ), separating one determination of @xmath3 from another, and then coalescing when one overtakes or collides with another. by means of the second law of thermodynamics,   it is shown that the uncertainty in the solution can be resolved by taking the formula for @x Math7 in case @x maths8, which is unambiguous, and letting @x math1 approach zero. on the other hand, the ambiguity in the answer to the question of the origin of the shock is not resolved by the method of characteristics, but by the use of the rankine - hugoniot jump conditions, which are known long ago in the theory of compressible
the search for sources of ultra - high energy cosmic rays ( uhec ) has begun to focus upon small scale anisotropy in event arrival directions.   the akeno giant air shower array ( agasa ) and the high resolution fly s eye ( hires ) experiment have both reported that they have observed clusters of events with estimated energies above @xmath2  ev. here   we apply the same analysis to both agasa and hires data to determine if the agasa claim of autocorrelation is justified.. the results show that the level of autoprotection observed in the hires data is completely consistent with that expected from background coincidences, which are independent of the angular resolution of the monocular experiments.
abstractinterstellar gas in the solar neighborhood has a variety of thermal and chemical phases, including cold atomic gas inside or mixed with cold molecular clouds, cool and warm atomic gas on the envelopes of molecular cloud envelopes, and hot, shock - heated gas near supernovae and windy stars.   the nature of these states is largely the result of turbulence, self - gravity, and local explosions, which seem to act the same way everywhere. here   we discuss the dominant processes that affect the molecular and thermal states of the gas, and we review the some of the aspects of cloud structure that are likely to arise from turbulence.
the vector - tensor multiplet is a variant of the @xmath0 supermultiplet which, with respect to@xmath1 supersymmetry, appears as a combination of one vector and one chiral multiplet @xcite.   this variant is irreducible under @x math0 and, in contrast, carries non - vanishing central charge off - shell. here   we present a superfield formulation of the free abelian case of the tensor - vector multiplet using superspace techniques. following the geometrical formulation of supergauge fields, we introduce a super - connection and the associated curvature. then we introduce the appropriate constraints, solve the bianchi identities and show how the component fields of the Tensor - Vector multiplet emerge. using supers space techniques we rederive the supersymmetric and central charge transformations and, after showing that there exist a lagrangian superfield in central charge superspace, we give the superfield and component actions.
the statistical toolkit @xcite was originally conceived as a statistical data analysis toolkit for the problem of comparing data distributions.   its development follows the unified software development process@xcite. according to this approach, the life - cycle of the software is iterative - incremental, every iteration representing an evolution, an improvement, an extension in comparison with the previous one.the first development cycles of the statistical toolbox implemented a set of goodness - of - fit ( gof ) tests for the two - sample problem ; these developments were motivated by experimental requirements for regression testing, validation of simulation with respect to experimental data, comparison of expected versus reconstructed distributions, and more in general for the comparison of data from different sources. during the current development cycle,   new requirements have been identified, based on the experience of using the statistics toolkit in several analyses for the validation of geant4 physics models. among them, the evaluation of differences in the behaviour of two geant 4 physics models with respectto a setof experimental test cases highlighted the need for complementary functionality, beyond the problem that assesses the compatibility of two distributions. here  , we describe the implementation of the latest version of the #xcite statistical tool
we investigate a renewable energy powered cognitive radio ( cr ) network, where a primary user ( pu ) shares spectrum with an secondary user ( su ). in each transmission slot, the su transmitter ( tx ) allocates the stored renewable energy for transmitting some data to the pu transmitter ( rx ). to guarantee the pu s transmission qos,   the isr at the pu rx should be less than a threshold. as delay is an important qos merit ( delay - sensitive traffic such as video increases sharply in wide - spectrum wireless networks, e.g., lte networks ), we focus on the average buffer delay minimization by scheduling the allocated renewable energy in each slot.   accordingly, a constrained stochastic optimization problem is formulated. based on activity of the constraints, we propose two algorithms : the optimal greedy algorithm and the optimal power re - allocation algorithm. when the renewable energy constraint is inactive ( i.e., the data constraint is not active in all slots ), the greedy algorithm gives the upper bound and lower bound for the achievable throughput of energy harvesting su. under the same circumstances, the optimal re - allocate algorithm provides the upper limit of the theoretical achievable throughput that is close to
hess  j1427608 is one of the unidentified ( unid ) very high energy ( vhe ) gamma - ray sources located at @xmath6 @xcite, and is extended with @x math7.   the flux is @x Math8 in the 110  tev band with a photon index of @x maths9 @xcites.. we observed hess j1427 608 with suzaku ( @xcire ) from 2010 january 13 through 16.    we also analyzed the xmm - newton archive data. to search for an x - ray counterpart  , we observed the sky region including hes  j 1427608 with xis0xis3 and xis3xmm-newton archive experiments. among the four sensors,   xis1 is not operational and a part of xis 0 ( corresponding to the off - source region in the latter analysis ) is not usable due to its anomaly. here, we present the results of the analyses of the x mm - newson archive data obtained from xis2 and Xis3 observations of hess j1426608.
we investigate coherent backscattering ( cbs ) of light by two atoms that are trapped in harmonic oscillators.   this model system can describe how atomic motion destroys multiple scattering interference via recoil and doppler effects. using general quantum duality relations derived by englert, we calculate the cbs interference visibility both at zero and finite temperature in shallow traps that allow to treat the limiting case of freely moving atoms. a two - way interferometer is then realized where the two mutually exclusive alternatives are the order in which the photon visits both atoms. if one knows which of both atoms has been visited first, the which - way distinguishability is present.
tracking and vertexing in a high multiplicity environment such as the lhc is a challenging task.   the cms experiment uses a hybrid pixel detector with a pixel size of @xmath1m@xmath2 pixel size and three layers at mean radii of 4.4, 7.3 and 10.2 cm2 for the innermost layer which reaches @x math3 at the full lhC luminosity of @ xmath4s@x Math5@x maths6.    the main purpose of the pixel detector is the reconstruction of secondary vertices ( mainly for b and @xMath7 physics ) and the generation of track seeds for the reconstruction in the full tracker. here   we describe the design and assembly of the barrel part of the sensor module for the experimental setup. to reach full spatial coverage the barrel support structure is made out of 53 cm long and 0.25 mm thin carbon fiber ladders glued to aluminum cooling pipes with 0.3 mm wall thickness. to achieve spatial coverage ladders are mounted with overlap on alternating sides of the cooling tubes. to get a good secondary vertex resolution one needs measurements as close to the interaction point as possible due to the large
the quantum spin - glass transition ( qsgt ) is a very active topic in theoretical physics, to which disorder and frustration of a quantum spin glass add considerable intricacies.   the density matrix renormalization group ( dmrg ) is known to be a highly accurate method to analyze ground state properties of 1d or quasi-1d quantum many body systems, including tree structures @xcite. here   we have extended the method in order to trace the behaviour of finite size samples of random graphs of fixed connectivity @xmath2 across the Qsgt within the random couplings ising model in a transverse field ( ritf ) model. given the high connectivity of these graphs,   it is remarkable that in the case of non - random coupling, we have found the number of retained states needed to ensure a good accuracy to be very high, rendering the application of the dmrg unfeasible. using the results of this study, we show that the quantum phase transition is not only reversible, but also non - reversible, and can be observed in both the 2d and 3d cases. for the latter case, the quasiexperimental phase is present in the
the statistical hadronisation model @xcite assumes that in high energy collisions, as a consequence of strong interaction dynamics, a set of colourless clusters ( or fireballs ) is formed having certain values of mass, volume, internal quantum numbers and momentum, the latter being inherited from the hard stage of the process.   those clusters are assumed to give rise to hadrons according to a pure statistical law in the multi - hadronic phase space defined by their mass, volumetric and quantum numbers. in this paper   we introduce a method allowing to rigorously and exhaustively determine the contribution of all particle decays. using this technique, we have performed an analysis of many measured transverse momentum spectra of identified hadrons in a wide range of centre - of - mass energies for several kind of collisions including pp and heavy ion collisions. here  , we show that the average values of many observables, e.g. particle multiplicites, are the same as those relevant to one equivalent cluster having suitable values of volume ( namely the sum of all cluster volumes measured in the rest frame of the equivalent cluster itself ), mass and quantum number ( namely, the sumof all the particles measured in each cluster )
in this talk, i discuss three topics which superficially would look unrelated but in essence can be connected by the general theme of cheshire cat.   i will first look at two - nucleon systems in terms of macroscopic variables of qcd, namely hadrons ; i will then go back to an elementary hadron and examine its microscopic structure by  punching " a hole in the proton and then putting quarks and gluons of the appropriate quantum numbers inside and argue that there is a continuity in the descriptions in terms for hadronic variables and for quark - gluon variables ; finally the continuity of qu atoms and hadrons at high density will be described in terms as qualitons  quark solitons.
magnetic reconnection is a fundamental process in astrophysical plasmas and is believed to be responsible for a wide range of solar phenomena, including solar flares.   the supra - arcade downflows that have been observed above many post - flare loop arcades are one of the most compelling pieces of indirect evidence that magnetic reconnection plays a central role in solar flares.the launch of the atmospheric imaging assembly ( aia ) on the _ solar dynamics observatory _ ( _ sdo_ ) provides a new opportunity to investigate the dynamics of newly reconnected flux tubes in sun - centered solar flares at high spatial resolution. with the improved capabilities of aia we are able to track features at larger heights and in much weaker events than in previous studies. here   we report new observations of supra - Arcade downflows taken with the aia and euvi imagers during the 20102012 time frame. despite the initial velocities measured for the downflows, which tend to be much smaller than the estimated alfvn speed in the lower corona, we find no evidence that the downflowing voids and loops are manifestations of the same phenomenon observed along different lines of sight.    we find that the
the direct detection of gravitational waves from a coalesced compact binary such as a neutron star is one of the most important tasks for theoretical relativists.   we have developed a new method for the analysis of gravitational wave emitted from a compact binary system, which is based on the perturbation analysis of the quasinormal modes of the black hole in a schwarzschild black hole spacetime. to achieve this goal, we have first formulated a method for metric perturbations in a black hole background spacetime and treated a companion of the neutron star binary as a test particle. using this method, we show that the results obtained by numerical simulation of the coalescence of two neutron stars are in good agreement with those obtained by solving the differential equation for the axial mode of the binary. however, because of the dynamical degrees of freedom of polar modes, i.e., sound waves and gravitational waves, the basic equation can be reduced to a fourth order differential equation if the effective potential has a minimal as that in an ultracompact star ( e.g., 0.5 kcal / mol ). also, we find that the rate constants of the gravitational waves emitted from the center of the
we model the process of landing of bird flocks performing foraging flights as a typical example of collective decision making.   we view this phenomena as a shift of the average opinion of the flock from that of continuing horizontal flight about some preferred altitude to that of descent towards the surface below. in our model,   the birds in flight are represented by particles characterized by the dynamical variables of position and velocity in three dimensional space. with this model we investigate the level of synchronicity in collective landing across time and space and explore the nature of fluctuations close to the point in time when landing occurs.
granular convection is a natural outcome of impact - induced seismic shaking on the surface of asteroid eros.   the onset criterion of the regolith convection depends on the maximum acceleration of the applied vibration. in this study, we experimentally measure and scale the granular convective velocity of the asteroid itokawa using the dimensionless parameter @xmath7 as a first - step approach to the analysis of the geometrical properties of granule convection.. the results show that the magnitude of the granules convection increases with the increase in the maximum vibrational acceleration from 0.5 to 1.0 m / s ( ~1.0 to 2.0 cm / s ), which is about two orders of magnitude smaller than the earth s gravitational acceleration. by applying the scaling method to the data obtained from the experiments, we find that the size segregation of the grains can be explained by the brazil nut effect, i.e., the grain migration and sorting can occur simultaneously.
isospectrality is a fundamental problem in the study of quantum graphs.   it is assumed that the spectral inversion of quantum graph spectra determines uniquely their connectivity matrices and their bond lengths. here   we show that this assumption is not the case, and that the nodal counts of eigenfunctions belonging to the same spectral value can be resolved by counting their nodal domains. for a set of finite graphs consisting of two vertices connected by two monte carlo surfaces,   the spectrum of the connectivity ( adjacency ) matrix is unbounded, and the bonds which connect the vertices are rationally independent. using the sunada method, we have shown that all the known isospectrum domains in @xmath0 @xcite have corresponding isosspectral pairs of quantum Graphs. however, we also show that the nodal count differences on a substantial fraction of the spectrum do not determine the length of the bonds or the connectivity of the graphs. finally, we propose that by counting the nodals of these eigen functions one can resolve the isos expectorantity of the systems presented.
the ongoing heavy ion physics program with the star detector at the rhic has accumulated a wealth of experimental data, stimulating important advances in the understanding of properties of hot strongly interacting matter @xcite.   some of the focus areas currently under study are the thermodynamic and hydrodynamic properties of the matter created, in - medium effects on parton propagation, and hadronization mechanisms in qcd matter. here   we review the latest results from the star particle identification and azimuthal correlation studies of quark - gluon plasma formation at rhic.
the large hadron collider ( lhc ) has resumed its physics program with proton - proton ( pp ) collisions at @xmath4 = 13 tev.   the measurement of light flavour particles production in these collisions provides important input for event generators to model the soft parton interactions and the hadronization processes. a full description of particle production in pp collisions can not be obtained from perturbative quantum chromodynamics and hence modelling efforts typically employ various empirical components that have to be adjusted based on experimental data. here   we present the results of the alice measurements of pp particle production at the highest centre - of - mass energy reached in the laboratory.
the magnetic topology of a stable filament and its surrounding field is almost universally accepted to have the structure of a twisted flux rope, meaning that the helical components of the arcades are opposite in sign to that of the coronal loops crossing high over the photospheric neutral line.   this is consistent with the interpretation of the h.hanle effect measurements, which show that quiescent ( non  active - region ) filaments have " inverse" magnetic polarity, so that their transverse field component is opposite in signs to those of the overlying coronal loop loops. for this topology,   it is natural to assume that one sign of helicity prevails throughout the flux rope and its overlying arcade ; however, if the filament is regarded as a sheared arcade whose intermediate legs or barbs are rooted in minority polarity on the " wrong" side of the neutral line, then the helicity of the filament itself would be opposite insign to that from that of these barbs, contrary to most theoretical models. here  , we show that the main axis of the erupting filament has a net helicity equal to the sum of the helicities of the original filament and
noncovalent functionalization of single - walled carbon nanotubes ( cnts ) with tetraphenyporphyrin ( tpp ) molecules is becoming a promising technique to explore functional materials for light - harvesting or optoelectronic applications.   the strength of the @xmath4-stacking interaction with respect to the cnt structural parameters, like the diameter and chirality, is still lacking. in the present work  , we investigate the physisorption of tpp on 42 different cnt species, including semiconducting and metallic cnts, and also on graphene using van der waals density functional theory ( vdw - df ) calculations. our results show that the diameter would be the relevant cnt parameter to explain the unusual strengths of the tpp @x math4- stacking interaction. regarding optical properties, we find that the transition bands of the isolated tpp remain at almost the same energy position than those found in the free - base and porphyrin - stacked tpp, being independent of the cne structural parameters. for the tmp adsorption on graphene,   we find a very strong binding energy, of about 3
microendoscopic microscopes and miniaturized microscopes have greatly expanded the number and depth of neuronal populations that can be visualized.   however, automatic methods for extracting cellular signals from this data are currently limited and suboptimal. in this paper, we propose an extended constrained nonnegative matrix factorization ( cnmf ) framework for microendoscopic data that can simultaneously segment cells and estimate changes in fluorescence in the temporal domain based on a matrix - factorization approach. to accomplish this  , we replace the rank-1 nmf approximation of the background with a more sophisticated approximation, which can better account the complex background and avoid absorbing cellular signals, and develop an efficient initialization procedure to extract neural activities with minimal influence from the background. by using this method, we can identify neurons with low signal - to - noise ratio ( snr ) and simultaneously denoise, deconvolve and demix large - scale microendoscillar micro endoscopic video data.
an abelian cover is a finite morphism of varieties which is the quotient map for a generically faithful action of a finite abelia group.   the paper @xcite contains a comprehensive theory of such covers in the case when @xmath2 is smooth and @x Math3 is normal. here, we extend this theory to the case of singular varieties. namely, we allow@xmath3 and @Xmath2 to be varieties satisfying serre s condition @x math4 and having double crossing singularities in codimension 1, which we abbreviate to g.d.c. for " generically double crossings " ( see   for the precise definition ).    our interest in this case lies in applications to the moduli theory. in this paper  , we give a comprehensive treatment of the situation. in section    we show that the theory of standard covers of @xaite has a very natural extension to the cases when @xiaomet2 is still smooth but @xMath3 is possibly g. d.c.. in section  we extend it to
radio galaxies in close proximity to each other are the subject of intense x - ray studies.   we present new sensitive observations of the abell3744 reflex cluster at @xmath3 with the jansky very large array ( jvla ), together with new radio data obtained with the rosat  all - sky survey ( rass ) and the galaxy velocity data from the vla. while the complex radio structures of the two radio galaxies are consistent with interaction with the cluster atmosphere, little has been published on the x -ray properties of the surrounding gas. using the rass data, we show that the central region of the cluster is dominated by a pair of radio galaxies with unusual extended structures, one with a bent extension on the jet side and the other with an extreme looping on the counterjet side, which we refer to as the'swirl'and'filament '. for the first time we find evidence for a merger of these two galaxies, and discuss the relationship between the radio and X - ray structures.
pseudodiffusive transmission refers to the @xmath1 scaling of the electrical current transmitted through a clean sheet of undoped graphene.   it is understood as a general property of massless dirac fermions in the limit of vanishing excitation energy. here   we show that this phenomenon is also true for layered superconductors with a symmetry of the order parameter ( notably the high-@xmath2 cuprates @xcite ), in which nodal fermion - like structures are located in the two - dimensional brillouin zone near the intersections of the fermi surface with lines ( nodal lines ) of vanishingexcitation gap. by matching the wave functions at the interface with the normal - metal  superconductor ( ns ) interfaces, we find that the transmission probabilities for transmission as an electron or as a hole are almost the same for both the nodal points and the ns interfaces. on the other hand, the electrical shot noise power and the transmitted thermal current remain finite in the range of lengths between @x Math7 and @x math3.    we interpret this result in terms of a resonant coupling via the nodals of the mid - gap states @xc
we study the effects of coulomb interaction on the ground state properties of cylindrical systems made of rolled square lattices ( multichannel systems ), without disorder but with coulombs potential, long or short range.   we are interested in how the couloms can affect the ground states of these systems when a static magnetic field is applied parallel to their planes and hence the behaviours of the persistent current. for cylinders, in the pure case and without electron - electron interaction, an axial magnetic field induces many level crossings at different values of the magnetic flux @xcite. with the cou lomb interaction,   there exist interaction between these degenerate states resulting in avoided crossings ; in other words, at least at the vicinity of the crossing points the ground State becomes a true many - body state unable to be described by any mean field treatment. in this work  , we propose a ` minimal'variational wave function to deal with this particular problem, going beyond a simple hartree - fock calculation. as a result, we find, in addition to the avoided crossing formation, two other effects caused by repulsive interaction : ( i ) the positions of the electronic channels in the lattice
the twist of the solar magnetic field plays an important role in transient phenomena such as solar flares and coronal mass ejections, and in the dynamo processes that cause the 11-year solar activity cycle.   magnetic helicity is an integral that quantifies topological complexity of field lines, such as linking, twist, or kinking. for a closed magnetic system it is defined by @xmath0, and alternative definitions have been developed for open systems @xcite. in this letter   we describe the distribution of current helicity in a 30-month simulation, which we hope to compare with new magnetic observations from the sdo ( nasa solar dynamics observatory ) mission.
secure multiparty quantum computation ( smqc ) is a fundamental cryptographic primitive in modern cryptography.   it focuses on the studies of secure computation among the players that do not trust each other. in this paper, we present a scheme of secure two - party quantum computation of nonlocal cnot ( nl - cnot ) using quantum fully homomorphic encryption ( qfhe ) and trusted third party ( ttp ) based on quantum key distribution ( qkd ) scheme. for some protocol @xmath9 and some protocol@xmath10,   we denote by @x Math9 and @x maths10, respectively. to study the security of the proposed scheme, we use quantum universal composition ( uc ) theorem, and then the protocol presented in @xcite can be simplified from one - sided to two - sided secure two-party quantum computation with bit commitment.
we study the single - site entanglement entropy @xmath0 near the mott transition ( mt ) in the fermionic hubbard model in infinite spatial dimensions using the dynamical mean - field theory ( dmft ) and the exact diagonalization method.   the results show that the singularity of the single- and two - site Entanglement Entanglements @x Math0 and @x math1 near the mt is determined by the local quantum fluctuations of electrons at the transition point, which are suppressed by the spatial fluctuations of the quantum fluctuation of the electron on site. for the one - dimensional hubbard models,   this singularity is due to equal population of all the local bases with respect to the mt. in the two - dimensional model, however, it is a consequence of the existence of a special second - order quantum phase transition ( qpt ) between the two states of thehubbard model.    we present numerical as well as analytical results for the analysis of the individual entangement properties of the hubbardian model in the infinite spatial dimension.
@xmath0 is a color index that is sensitive to the fraction of young stars.   it can be used to localize giant emission regions of a galaxy where @x Math13 line locally increases r luminosity of the disk. in this paper   we show how the values of q s change when young stars formed in a single burst with the age t=0.1 gyr are overlapped onto the old population ( t=13 gyr ) for different relative mass of youngstars.    the model values of Q s which do not take into account recently formed stars ( t@xmath19 ) are obtained by using the combined color index @x math1 whose value does nt depend on selective attennuation of light to trace the structure of galaxies.
the yukawa one - component plasma model is often used to describe the heavy plasma component while the light component determines the screening length. here   we investigate the normal modes of a yuk Kawasawa plasma in a spherical, harmonic confinement  @xcite.   this model is appropriate for the experiments of @xcite, where the screening of the interaction between the two charged components is mainly determined by ions. using a time - dependent continuum theory,   the ground state potential and energy are calculated and the eigenfrequency spectrum is derived. from these results  , we show that the density profile of a three - dimensional dusty plasma, where gravity is balanced by a thermophoretic force, is not homogeneous due to the screened dust - dust interaction which produces an inhomogeneous density profile in a harmonic confinement. on the other hand, the confinement is provided by gravity and may also influence the plasma properties.
the coulomb glass @xcite is a prominent example of a disordered system of localized states in a semiconductor.   the main aim of this work is to study numerically non - ergodic effects in the coulomomb glass analyzing the transitions between low - energy many - particle states, and to investigate the influence of temperature, duration of measurement, disorder, dimensionality, and dimensionality on these effects. for this purpose, we consider a sample of an n - type, partially compensated semiconductor with donor concentration @xmath1 and acceptor concentration@xmath2, and a diameter of 0.5  nm. using the classical impurity band model, we calculate the transition probabilities between low- and high - energyMany-particle states in the quasiexperimental state space of the glass, and map the dynamical behavior of the sample to a graph. by analyzing the structure of this graph  , we determine the value of a physical observable in dependence on the duration of its measurement. in sec.v, we use this method for the investigation of the non -ergodic effect of the quantum interference in the specific heat, and find evidence for a dynam
the prisoner s dilemma ( pd ) game is a useful tool for studying cooperative interactions among self - interested agents.   the game involves two players each confronting two choices : cooperate ( c ) or defect ( d ) and each makes his choice without knowing what the other will do. in this article, we review the history of the pd game and its application to the study of cooperation among animals as a tool for understanding the evolution of evolutionary game theory.
the definition of the parton distribution operator in deeply inelastic scattering ( dis ) requires the inclusion of wilson lines in order to render its definitions gauge invariant.   the most known procedure is the direct resummation of the collinear gluon radiation diagrams, and this method can be applied to transverse momentum dependent ( tmd ) processes as well, and it allows to determine the appropriate configuration of wilton lines in the partone distribution functions that parameterize them. in this note   we want to discuss a procedure which allows one to reveal the geometry of the wilson - line geometry in hard processes using the freedom of the gauge redefinition of the fields in the qcd lagrangian and the fact that the choice of a particular gauge can be implemented by performing an explicit gauge rotation. for the sake of clarity, we start with a heuristic discussion to demonstrate this idea in the case of dis, and consider then the tmd factorization of the drell - yan process as an application of this technique.
molecular wires are molecules that bridge between metallic leads to form a nano - conductor whose current - voltage characteristic reflects the electronic structure of the molecule. understanding the behavior of such junctions under potential bias is a prerequisite for elucidating their transport properties.   the most recent work by datta and coworkers @xcite has shown that the potential profile imposed on the molecule as input to the extended - hckel ( eh ) model for @xmath0,@xmath1-xylyl dithiol bridging between two gold leads had a profound effect on quantitative as well as qualitative aspects of the calculated current - voltammetry characteristic. in this article   we discuss the implications of these results for the conductance of molecular junctions.
a new solution to the einstein - maxwell system of equations that govern the behaviour of the space - time in the interior of a charged fluid sphere is presented.   the solutions are given in curvature coordinates and compared to the reissner - nordstrm solution for the exterior vacuum field equations. at the outer boundary   these solutions are matched to the external vacuum solution for each of the field equations, i.e. the vacuum solution. it is shown that some of the solutions have parameter values that lead to physically realistic properties.
we present a new algorithm for measuring the 3-point correlation function ( 3pcf ) of galaxies through its multipole moments.   this decomposition is particularly useful for distinguishing linear and non - linear bias as well as isolating a possible relative velocity bias. in this work  , we present an algorithm that scales as the number of galaxies in the survey times the number within @xmath2, and so by construction is significantly faster than any previous algorithm that is exact in angle. to achieve this, we write the opening angle dependence of the triangles about a given vertex in terms of legendre polynomials of the three - point polynomial of the monopole moments of the mean and two - point correlation functions ( 2pcf and 3p cf ). using this approach,   we find that the average separation of the galaxy redshift survey data from the baryon oscillation spectroscopic survey ( boss ) is much smaller than the scale that is well - described by linear perturbation theory and hence most useful for cosmology.
we study the evolution of the eccentricity distribution of extrasolar planets at moderately large orbital radii under the combined action of planet - planet and planetesimal scattering.   we use pure n - body simulations of three planet systems in which the masses of the planets are chosen randomly in the range @xmath5, with a distribution that matches that observed from observations of debris disks of leftover gas disk debris ( ~30 - 50    50  kj / cm2 ) around the outer solar system. for the first 1000 integrations of the highmass set, we ignore the gas disk and study the subsequent evolution of both the equilibrium eccentricity and the semi - major axes of the two or more massive planets as they interact with an external planetesmal disk of residual gas and a residual gas disk of leftover debris. by contrast, for the lowmass sets, we focus on the final eccentricity of the orbits of the massive planets at very large radial radii where the mass of the remnant gas disk is negligible. using a combination of model and observation data, we find that the initial eccentricity distributions of the stars are consistent with simple models of gravitational scattering among a system of massive planets that typically include neither planet
the superfluid transition from a uniform two - dimensional ( 2d ) system to a superfluid with quasi - long range order is investigated via laser stirring of a trapped 2d bose gas of @xmath0rb atoms with a blue - detuned laser.   we provide a quantitative understanding of the experiment using a c - field simulation method, which shows that dissipation of the superfluid density occurs via the creation of vortex - antivortex pairs. in contrast to laser stirring with a red - detune laser, where dissipation occurs via phonons, this dissipation is caused by vortex recombination and diffusion rather than thermal fluctuations.
the light - cone sum rule ( lcsr ) is a non - perturbative method that has been successfully applied to various problems in heavy meson physics.   the present paper aims to give a preliminary determination of the form factors of the exclusive semi - leptonic decay @xmath1. in the calculation   we will use the method of qcd sum rules on the light cone @xcite and adopt two different kinds of interpolating currents to investigate the process.
strong matter - light coupling between organic molecules and light in optical microcavities can be engineered by confining light in the cavity, so as to modify the density of states and the coupling to matter.   this work has focused on the effects of strong coupling to electromagnetic modes on the optical spectra of strongly - coupled organic microcave polaritons, but there has been significant recent work on the effect of coupling in the vacuum state, i.e.  without strong pumping. in this paper   we examine the behavior of such strongly- and weak - coupled systems starting from various microscopic models, allowing quantitative predictions of the extent to which a self - consistent adaptation of the molecular state, driven by coupling with light, may occur. using the ebbesen group s recently published experimental data on the influence of concentration and temperature on the polariton splitting of highly coupled organic nanocrystals, we show that the resonance energy of the two polariton peaks in the absorption spectrum is significantly different for each molecule at room temperature, and that the resonant features of the second peak are more strongly affected by temperature than by concentration. these results suggest that the mechanism of the variation in the polarization of the resonance energies of
the soho / mdi - debrecen sunspot data ( sdd ) are a new database of the internal processes and morphological properties of solar active regions.   the main objective of this report is to present some preliminary results from the investigation of the emergence / decay of the magnetic polarity distance of the emerging bipolar active regions and the relationship between the total areas of sunspot groups and the distances between the centers of weight of their leading and following parts at the time of the largest total umbra - penumbra area of the sunspot group. for the first time  , the development profiles of two active regions are plotted separately along with the separation of their center of weight. in the case of the noaa 10988 and noaa 10311 active regions there is a significant increase in the number of spots in the leading part of the active region and a significant decrease in the size of the trailing part. on the other hand, the formation of the leading - following parts is more or less symmetric and the observed asymmetry is related to the magnetic tension of the flux ropes and the erosion process caused by the turbulent environment of the emerged flux ropes.. the most detailed analysis of these phenomena is
the (, ; hereafter, the ) is one of the first infrared sources discovered with an optical bipolar nebulosity @xcite.   it consists of a central star in the post - asymptotic giant branch ( post - agb ) phase and the physically - detached circumstellar shell, which is a consequence of mass loss during the preceding agb phase. to understand the dynamics of the circumstellar structure formation, we performed differential proper - motion measurements of the concentric arcs using the archived imaging - polarimetry data from wfpc2 and acs / wfc, exploiting the data set s largest field of view, longest exposure time, and longest temporal baseline to overcome the deficiencies of the previous analyses. for the bipolar lobes and the equatorial structures of the nebula, we found that ( 1 ) the lobes expanded linearly ( i.e., the expansion velocity linearly proportional to the distance to the expansion center ), ( 2 ) the distances to the was @xmath5  pc, and ( 3 ) the object ( star and nebula ) itself experienced its own proper motion at (@xmath6, @x Math7 ) mas yr@x math2 @
the modulational instability of the continuous - wave ( cw ) plane - wave background which supports @xmath1 dark solitons ( dss ) in a three - wave model is investigated.   two types of cw solutions are identified and analyzed, as well as the stability of the cw states when they are stable. for the first time,   a stable dark bi - soliton in this model was found numerically near the band edge @xcite.
the time evolution of a system after a quantum quench, at which a global parameter in the hamiltonian is suddenly changed, is studied.   we consider a well - defined situation, which can be handled to a sufficient degree of exactness to provide some partial but reliable insights into some of the most important questions in quantum relaxation theory. using exact wavefunctions for the heisenberg magnet, we show that the eigenstates we use to study the relaxation dynamics of strongly - correlated systems are not necessarily equilibriated. on the one hand, this renders some of our results non - generic, but on the other hand, we are able to provide hard facts for finite as well as infinite systems, gapped versus gapless, and exclude some possible scenarios. since the theoretical understanding of the nonequilibrium dynamics of highly correlated systems is still in its infancy, such example cases will hopefully provide worthwhile reference points for later developments.
the electromagnetic casimir interaction between a compact object and a planar surface is one of the most important interactions in the field of quantum mechanics.   it is dominated by fluctuation forces due to the coordinated behavior of fluctuating charges or collective modes inside the objects. at very small or asymptotically large separations,   the interaction is governed by the casimir - polder potential that was derived for the case of an atom and a perfectly conducting plane.. recently, there have been first attempts to go beyond the two extreme limits of asymptonically large and small separations by measuring the force between a sphere and a plane over a larger range of ratios of sphere radius to distance. here   we present a new method based on a multipole expansion of the functional determinant formula for the electromagnetic Casimir energy between a parallel plate and a cylinder with a diameter much larger than the surface distance. using this method  , we show that the effect of geometry and shape can be accounted for by the proximity force approximation ( pfa ) which is assumed to describe the interaction for sufficiently small ratios of radius of curvature to distance ; however, this assumption is uncontrolled for infinitesimal separations
we have recently constructed a model of fermion masses in which the mass matrix is almost of the pure phase form and is constructed out of four plus two extra compact spatial dimensions.   along the way, we found a special region in the allowed parameter space that fits the ckm matrix, where the parameter @xmath0 of the famous strong cyclic voltammetry ( cp ) problem can be found to satisfy the experimental bound@xmath8.    this result is somewhat surprising since it is not at all evident that solutions of our model that fit both the mass spectrum and the c km matrix could also give values of @x Math0 below the experimental limit. in this paper  , we present some thoughts on the possible physics which might be responsible for this behaviour.
we investigate an optimal stopping problem under partial observation for piecewise - deterministic markov processes ( pdmp s ) both from the theoretical and numerical points of view.   we study the problem by comparing the observed information with the state space and local characteristics of the discrete time markov chain, which is a general class of stochastic models involving deterministic motion punctuated by random jumps. in this paper  , we focus on the optimization problem for a partially observed pdMP where the process is not piecewise deterministic. to achieve this, we reformulate the initial problem into a completely observed optimal solving problem where the new state variable is the filter process.    our work is inspired by the recent work by davis @xcite which deals with an optimal filtering problem underpartial observation for a markov chains with finite state space. here, we propose a discretization method based on a quantization technique to approximate the value function of the filtered process.
nova outbursts are thermonuclear runaway events on white dwarfs.   the decay phase of nova is followed by a quasi - evolution theory which is to make a sequence of optically thick wind solutions of expanding envelope. in this review,   we discuss the evolution of the optical and uv light curves of the classical nova cygni 1978 and the recurrent nova with different composition ( kato 1997, kato 1999 ; hachisu 1994, hachi et al., j. d. kato, m. t. hachiku, p. w. shapiro, r. b. nakamura, s. c. chiao, e. l. yamaguchi, f. g. zhang, v. o. kashima, i. j. katao, mb.j. katsumoto, jm.kato, jr.nakita, js.h. kajimori, jc.w. katohama, jp.d. kasuguchi, jy.g. kazuhiko, jt.k. katsuura, jf
we have studied the accretion of young stellar objects ( ysos ) in ngc  2264, a t  tauri star in the keplerian region of the inner circumstellar disk.   we find that the rate of accretion is variable on timescales of a few hours and days for typical masses and rotation periods of yso stars. at the same time, the magnetic field of the central star is strong enough to generate a shock that heats the accreted mass to x - ray emitting temperatures, which can be measured by the @xcite infrared array camera ( irac, *?????   * ). here  , we show that this shock can be explained by two different mechanisms : ( 1 ) magnetically confined accretion funnels and ( 2 ) magneto - hydrodynamical instability. using the optical and infrared spectroscopy of the v1647  ori star, we find evidence for the existence of an accretion shock in the outer edge of the gas disk that is driven by magnetic activity similar to our sun and also by hot spots which mark the impact points of the accrete funnels onto the stellar surface. these hot spots
chaos is a fundamental concept in physics.   it is based on the idea of randomness, but at the same time it creates a new type of universality in the representation of reality. since majority of systems in nature are chaotic, at least to a considerable extent, this type of description is often the ultimate one. among the physical systems that materialize the signatures of chaos in nature, an important place is held by atomic nuclei. despite the fact that even more than 80 years after the discovery of their composition we are not able to present a satisfactory microscopic theory of nuclear structure, we are still able to show that nuclei are indeed chaotic objects par excellence.. however, atomic nucleus not only show well recognized signs of chaos, they also provide a variety of models that can be used to better understand the rules of chaos for a more general context. in this review   we want to make a passage through selected topics of classical and quantum chaos using models taken from the description of nuclear collective dynamics. before diving into the ocean of chaos  , we have to briefly introduce the models we will be playing with : the old ( and the good ) geometric collective model ( below abbreviated as gcm
understanding the physics of the hubbard model is a fundamental issue in strongly correlated systems.   this model captures the transition between a metallic state and a correlated insulator ; how this transition takes place has been investigated by many workers in the past, with differing approaches emphasizing the formation of hubbard bands,   the increasing mass of the quasiparticles   @xcite and the proximity to antiferromagnetism. in this paper   we present an extension of potthoff s " two - site " approach to treat cluster dynamical mean - field theory ( dmft ) based on the non - interacting bath of electrons that couples to the impurity in dm ftp. using a two - dimensional square lattice with nearest neighbor hopping as an example case  , we show that our method can be used to solve the self - consistent equations for the mott transition for a single band hubbardian model on a 2d hubbard lattice. when applied to a cluster consisting of a pair of sites, the results are consistent with other work in the literature for the magnetic phase diagram and the zero temperature phase diagram.
magnetic skyrmions are topological protected textures of the magnetization that have been observed experimentally in various magnetic materials, in both bulk systems and thin magnetic layers.   they are stable and possess a peculiar particle - like nature, which makes them suitable for the application as an information carrier. in this paper  , we study in detail the motion and dynamics of an isolated magnetic Skyrmion in a magnetic nanowire driven by spin waves propagating longitudinal or transverse to the wire. with the help of micromagnetic simulations, we find that the steady - state motion of the skyr mion is determined by an interplay of the magnonic driving and the repulsive potential arising from the edge of the wire, i.e., it is pushed into the driving layer, that generates the spin waves. for large magnon currents,   however, the skirrmion is pushed towards the driving current, leading to a breakdown of the skating motion.
we use data from the twitter micro - blogging system to investigate the relation between activity profiles over time and content.   we focus our analysis on those hashtags that exhibited a popularity peak during our observation period, and systematically analyze the corresponding messages ( " tweets " ) by grounding the words they contain in a semantic lexicon. using this approach  , we identify dynamical classes of hashtag usage and relate them to the semantics of the corresponding tweets. in particular, we relate the same dynamical class to the spreading properties of hashtags over the underlying social network.
the fragmentation of molecular clouds ( mcs ) induced by supersonic turbulence is a fundamental aspect of the star formation process.   recent models of star formation rate and of the stellar initial mass function @xcite are based on the statistics of turbulent fragmentation, such as the probability density function of gas density and the scalings of velocity and density fluctuations. to test the idea that molecular cloud turbulence is driven primarily by single - photon ( sn ) explosions, we have carried out a magneto - hydrodynamic adaptive - mesh - refinement ( amr ) simulation of sn - driven turbulence in a large - scale sample of mcs with realistic initial and boundary conditions. using tracer particles, we show that the turbulence in mcs is driven by sn explosions, and that they form and disperse in approximately four dynamical times. using the data from the simulations, we study the compressive ratio of the turbulence and its relation to the distributions of density fluctuations and the velocity scaling laws of the whole volume and within individual mcs, showing that it is efficiently injected into mcs through a mechanism that is well suited for larger - scale simulations.
a statistical mechanics for jammed granular matter is needed in the absence of energy conservation laws.   the volume function proposed by edwards @xcite has been used as a conservative quantity of the system to describe the microstates of jammed matter. here   we introduce a new " hamiltonian " that describes the microstate of jammed material at the microscopic level, using a theory of volume fluctuations to calculate a coarse - grained average volume function defined at the mesoscopic level that reduces the degrees of freedom to only the coordination number @xmath5 and provides an equation of state, relating volume with coordination number in the limit of fully random system. our results allow construction of a statistical partition function from which macroscopic observables can be calculated.
the effect of strong quantizing magnetic field on the transport coefficients of dense stellar electron - proton plasma is studied.   we follow an exact formalism @xcite, which is applicable for a wide range of magnetic field strengths and obtain the transport coefficient from the relativistic version of boltzmann kinetic equation by linearizing the distribution function and using relaxation time approximation. to obtain the relaxation time from the rates of standard electromagnetic processes taking place inside electron-proton plasma, we make necessary modification in the rate calculation due to the presence of strong quantitative magnetic field at the core region of a magnetar.. the results show that the mean free path of neutrino emissivity decreases significantly in presence of very strong magnetic field ( @xmath5 g ) and the mean number of electrons occupying the zeroth landau level increases significantly ( p < 0.05 ).    the mean mass - radius relation of neutron star matter also decreases significantly with the increase in the strength of the magnetic field ; however, the difference is not statistically significant.
we introduce a quantum version of the hamiltonian constraint of canonical general relativity based on the loop derivative.   we extend the notion of vassiliev invariant and other invariants associated with chern   simons theory to the context of spin networks and show that they are loop differentiable in the sense of distributions. by extending the space of invariants through the construction of new " habitats " such that the resulting states are not diffeomorphism invariant  , we can recover the classical poisson algebra of commutators at the level of quantum commutator algebra. using these new habitats   it is shown that the operators exist and we can compute correctly thecommutators.    we show that the results obtained will be later applied in specific " habitats" in which we will show that there are no anomalies, therefore constituting a consistent theory of canonical quantum gravity.
we introduce three forms of generalized contractive systems  ( gcss ).   these are motivated by requiring to take place only after arbitrarily small transients in time and/or amplitude, and require that the system is not contractive with respect to any norm. here   we show that these conditions are checkable, and demonstrate their usefulness using examples of systems that are _ not  contractive on a given norm, yet are gcss.
exact solutions of the einstein field equations are associated to highly idealized physical systems that have some exceptional geometrical properties.   in particular disk like configurations of matter are of great interest, since they can be used as models of galaxies or accretion disks. in this paper   we present a generalization of the g - method for the solution of the vacuum einstein equations corresponding to static thin disks and thin disks with halos made of perfect fluids. by using the well known " displace, cut and reflect " method we show that the diameter of the disk can be increased from 0.5 to 1.0@xmath0 by adding a new dimension to the distance between the origin and the end of the source ( energy - momentum tensor ). in order to obtain these new dimensions the same exact solution is also obtained by solving the riemann - hilbert problem which is commonly used to generate disks by the jena group @xcite. on the basis of this study   it is shown that the model is more realistic than the one previously published in @xaicite.
abstractthe shaping mechanisms of massive stars and aspherical planetary nebulae ( pne ) share common themes : binaries / mergers vs.interacting winds vs. rotating ejections.   however, for massive stars, magnetic fields still seem to be mostly taboo for the time - being. here  , i discuss some recent results for eta carinae and a few other massive stars that challenge some familiar ideas developed from the study of pne, and ask if conclusions gleaned from massive stars can inform the shaping mechanisms in pne.
the local group is a small galaxy group composed of galaxies that are isolated from the general field.   it is located in the outer reaches of the virgo supercluster, and has a virial mass of ( 2.3 x 0.6 ) x @xmath2 m@xmath3. since the local group contains no supergiant galaxies like m31 and the milky way system, its integrated luminosity is about 50 times smaller than that of the small antlia group. by comparing the observed radial velocity dispersion of the local groups members with the calculated values of the dynamical mass - to - light ratio of the barycenter of thelocal group, it is found that most of them are dominated by invisible matter.
we study a model of supersymmetric surfaces that constitutes a sort of classical limit of the ikkt matrix model @xcite obtained by sending the matrix size @xmath0 to infinity.   the model is introduced in such a way that in principle the model can be straightforwardly discretized. by re - writing the iib string action in the schild gauge, one avoids the problems related to the proper treatment of the local @x math15-symmetry in the discretization. for the model with fermions   we estimate the large behaviour of the partition function by assuming that it is dominated by tube  like configurations.the results presented here give an insight into typical geometrical features of surfaces that play an important role in the ensemble generated by the ikkt matrix model@xcite.
phenix @xcite is a large, widely spread collaboration where many organizations from many countries participate ( 12 nations, 57 institutions, about 400 collaborators, about 1/4 pb is planned to be produced in the current year ).   the collaboration is in third year of data taking. during this time   there has been a lot of progress in the development of phenix computing environment for physics analysis. here   we discuss some of the most important features of the collaboration.
electronic nematic phases have been proposed to be the quantum counterpart of nematic classical liquid crystal phases in transition metal materials such as @xcite.   experiments on ultra - pure bilayer ruthenate samples revealed an unusual phase characterized by a pronounced residual resistivity in place of a putative meta - magnetic quantum critical point ( qcp ) at low temperature and, remarkably, a significant in - plane magnetoresistive anisotropy when the external field is slightly tilted towards one of the in - Plane crystal axes@xcite which strongly implies the formation of an anisotropic metallic electronic nematic phase in the compound. here  , we show that the nematic qcp is accompanied by a nearby jump in nematicity, dubbed here meta - nematic transition, which obscures the qcp. using two nematic order parameters relevant for multi - orbital systems, t@xmath9-orbital systems and moderate spin - orbit coupling, we find that the presence of a large number of spin - up fermi species in the system is a key property for turning a nematic first order transition into a qcp with a near - van hove singularity.
microwave cavities and resonators are important scientific tools used in many physical, chemical, biological and engineering applications to boost system performance.   various cavities are used as sensors, clocks, spectroscopy, probes of fundamental physics and as building blocks of future quantum systems. in this work   we present a new approach to cavity design based on the recently proposed multi - post re - entrant cavity that is flexible enough to meet all these criteria simultaneously together with extra new features. for this purpose,   the cavity design is reduced to an arrangement of posts on a two dimensional lattice and investigation of the cavity properties with respect to different 2d arrangements is presented. from the results  , we draw analogies with existing physical systems such as microstrip circuits and fabry - perot modes.. additionally, we give an example of a multipost structure that may be used as a quantum memory.
hollow nanoparticles are anisotropic layered materials of finite size.   they combine covalent in - plane strength with flexible out - of - plane bending of thin films, which results in high mechanical stability. here   we discuss structural properties of spherical hollow nanoparticles in a continuum approach that allows us to focus on unusual generic properties which result mainly from geometrical effects. for this purpose, we use classical continuum elasticity theory, which is asymptotically correct for large systems and allows you to treat all these systems using the same framework. by means of this approach  , we show that the shape of the hollow nanoparticle is determined by the van der waals interaction between the nanotubes and the fullerenes, which leads to the formation of a hexagonal lattice structure with a diameter of about 1 nm at the end of the nanometer range. when the two sheets are adhered to each other or to flat surfaces, the geometry of the lattice is affected by the presence of local surface features like crystal steps, and the deformation of the layers is due to non - specific adhesion of the carbon nanotube to the hollow particles.
solid shells and lipid bilayers are two types of hard condensed matter.   solid shells are characterized by their in - plane shear stress resistance, whereas lipid bilayer is characterized by its softness and its ability to withstand the in - planes shear stresses.. the mechanical properties of solid shells have attracted much attention for a long time but the effects of shape fluctuations on the properties of lipid bil layers have not been well studied. in this review,   we discuss the recent advances in the understanding of the physical properties of thin thickness lipid bilays and solid shells.
weak lensing is a powerful method to measure the mass of galaxy clusters at low redshift.   we have recently reported a weak lensing measurement of the coma cluster from the sloan digital sky survey ( sdss ) which is the lowest redshift cluster ever measured in the sdss. since this study we have begun a program to measure other nearby, low redshifted clusters in the SDss using weak lensed galaxies. in this letter  We present the first results from our campaign using clusters selected from two publicly available spectroscopic galaxy cluster catalogs in thesdss : the c4 catalog of @xcite and the @xcitescope catalog.. we find that the mean mass of the whole cluster sample is ~1.5 times larger than that of the entire c4 cluster ( ~2.0  105  109 mpc s1 ) and ~3 orders of magnitude larger than the average mass of all the other clusters in both catalogs ( ~6.8  103 mpcS1 ). by taking advantage of the large imaging area provided by the sd ss and " going wide "  , we also find that there is a significant difference in the cluster mass between
interactions between neutral dielectric bodies are traditionally viewed as being due predominantly to electromagnetic field fluctuations, or equivalently, dipole fluctuations that give rise to van der waals ( vdw ) fluctuation - induced interactions between them.   these interactions are attractive between identical bodies in vacuum or in a polarizable medium, such as water or an aqueous electrolyte ( or coulomb fluid ), and contribute one of the two key ingredients of the classical derjaguin - landau - verwey - overbeek ( dlvo ) theory of colloidal stability, the other one being the mean - field electrostatic interaction, which is repulsive for like - charged colloidal surfaces. in this paper  , we study the effect of charge heterogeneity and disorder on the effective interactions between neutral surface charges in a weakly coupled coulomomb fluid, containing mobile multivalent ions. by assuming that the surfaces are neutral only _ on the average _, while microscopically they carry a  quenched  ( fixed ) ( positive and negative ) ( fixed)positive and negative charges, we show that this seemingly simple generalization leads to significant qualitative changes in the distribution of ions and
the optical properties of metal nanoparticles ( nps ) under tight illuminations have been extensively investigated in the experimental practice.   however, there is no detailed study on the effect of strong focusing on the plasmon spectrum of metal nps. by solving the scattering problem using a multipole - expansion approach  , we show that even when the np is smaller than the focal spot, the difference in the multipole content of the high - numerical - aperture ( high - na ) beam compared to a plane wave ( pw ) causes a modification of the plausson spectrum, especially when the metal np exhibits resonances of order higher than the dipolar one.
we characterize two ( 2d ) and three ( 3d ) delocalizing curves of gap - solitons in terms of an unstable solution of the multidimensional gross - pitaeviskii equation, which we call gap - townes soliton.   this solution can be viewed as a separatrix ( it separates gap soliton states from extended ( bloch ) states ) states and reduces to the known townes Soliton when the strength of the optical lattice goes to zero. for the 1d nonlinear schdinger equation with higher order nonlinearities in separable bose - einstein condensates ( ols ), we find that, except for strengths below the critical threshold, the same results are obtained for the 2d and 3d gpe with quintic and septic nonlinearity, respectively. on the basis of this characterization   we show that the soliton existence range in parameter space can be expanded from a single point to a whole interval @xcite.
the embedding method is used to study the superconformal structure of four - dimensional @xmath0 chiral conformal superspaces.   the results are equivalent to those obtained with twistor calculations for arbitrary values of@xmath2. in the case of scalar and holomorphic fields, the same results are obtained by considering more fermionic coordinates @x Math18, with @x maths19.. automatically, more bosonic variables @x math20 also appear in the six - dimensional superspace, which will be embedded into the original space - time using the same method. as a consequence, the theory can be formulated in such a way that the conformal group acts linearly on the coordinates, in the same fashion as the angular momentum does.
we study the emergence of collective mean - field dynamics in ensembles with random interactions using a shell model approach with a two - body interaction hamiltonian.   the results show that the number of realizations with a ground state spin of zero is disproportionally large in the two-body random ensemble ( tbre ) and that the probability of finding a coherent paired structure in the wave - functions of low - lying states is enhanced by the presence of rotational symmetries. to identify and analyze manifestations of collective phenomena in the spectra   we use a set of observables, namely, the reduced transition rate from an initial state to a final state, the angular momentum of the ground state, and the spin of the many - body state. for each of these observables we choose a finite number of spectral observables that are likely to convey the most information about possible collective structures in a scale - independent way and with minimal model dependence.
the one - dimensional ( 1d ) bose and fermi degenerate gases with zero - range interactions are celebrated examples of exactly solvable many - body problems @xcite.   it has been shown that the eigenstates of these systems are given by the bethe ansatz ( ba ) and are thus integrable in the limit of large effective range, i.e., when the actual radius of the interacting potentials is formally zero whereas the effective range and the scattering length of the model are finite. using a contact model ( cm ) and a hamiltonian two - channel model ( htcm ), it was shown for one - component fermions and identical bosons that this result is in strong contradiction with the mcguire - yang - baxter criterion which when applied in this regime shows diffractive effects in multiple scattering@xcite ; hence integrability is inherently not possible. in this paper, we consider the three - body problem, which is intimately related to the integration issue. to this end   we use a hamiltonshannonian two-channel model, which encapsulates the feshbach mechanism. whereas the cm and the h tcm
we show that partially hyperbolic diffeomorphisms defined on a 3-manifold with boundary exhibiting two intermingled physical measures are not robust.   we give some basic definitions necessary to formulate the results, but the reader can find the precise definitions, properties and more detailed information in section   and the references therein.
atom interferometry has opened new frontiers in precision metrology.   highly sensitive gravimeters, gravity gradiometers, and gyroscopes have been constructed, and promising work has been done to integrate these sensors into a robust apparatus that can operate outside the laboratory with applications in inertial navigation and geodesy @xcite. for measurements of the fine structure constant, the sensitivity is proportional to the separation in momentum that can be attained between the two arms of the interferometer ( ~1.5  kcal / mol ). however, the required laser intensities to make significant improvements on this result may prove to be prohibitive. here  , we provide a rigorous analytical treatment of this problem. using this analysis,   we propose atoms interferometric geometries in which optical lattices are used to continuously guide the atoms, so that the atomic trajectories are precisely controlled for the duration of theinterferometer sequence, with a different lattice guiding each arm of the Interferometer.
the renormalisation of the non - anticommutative wess - zumino model in four dimensions and its one - loop divergences in two dimensions is investigated.   the results show that the quantum field deformation in @xmath0 supersymmetry is unrenormalised at one loop, and that the yukawa couplings for all the terms which may be generated by the renormalization process are independent of the gauge group.
compact binary ( neutron star - neutron star, ns@xmath1, or black hole - neutronstar, bh - ns ) mergers are prime sources of gravitational radiation.   the gw detectors ligo and virgo are being upgraded now and by the end of 2015 are expected to be operational at sensitivities @xmath2 times greater than the initial ligo @xcite. understanding the observable electromagnetic ( em ) signature of compact binary mergers will enable us to determine the expected rates, a question of outmost importance for the design and the operation policy of the advanced detectors. in this article   we discuss the recent work on the detection of short gamma - ray burst ( grb ) orphan afterglows from coalescence events from compact binary merger events.
optical flow is a powerful tool for visualizing the spatial and temporal properties of an image.   it is one of the most crucial steps in the optical flow pipeline, as it transforms a sparse list of matches into dense maps of optical flow. here  , we propose a neural network based sparse - to - dense interpolation method for optical flow that is more robust than the current state of the art and can be adjusted to different matching algorithms. by introducing a new lateral dependency loss, embedding the correlations between neighbors into the learning process, we introduce a novel architecture involving detour networks in each layer of the network. using this architecture, we show that the performance of our network is significantly improved compared to epicflow, which is the current default optical flow method.. we also show that motion boundaries are important for learning dense interpolations.
the casimir effect is a quantum effect caused by a shift in the zero - point energy of gauge field fluctuations such as the electromagnetic one.   it has been shown that in layered and strongly anisotropic superconductors the thermal fluctuations of the flux lines of the applied magnetic field give rise to a long range attraction between the vortex matter and the dielectric media, which attracts the charged bosons via a casimir force. here  , we present a derivation of the van der waals force between vortex lines via this alternative route, calculating first the cas Vladimir force between two dielectic planar media in the boson picture and then reconstructing the vander waals forces in the reductionist way.. the casimir interaction between the vortices in the vortex - vortex interaction can be derived from the imaginary time quantum mechanics of two - dimensional ( 2d ) bosons using a path integral formulation of the london functional describing the zeta potentials of the vourvacane flux lines. for dilute media,   the macroscopic casimir Force can be related to the microscopic van der Waals force through pairwise summation. within the case of raref
the chinese rings puzzle is a popular puzzle that has been known for hundreds of years.   the goal of this paper is to prove that a particular solution of the puzzle is the simplest possible, as conjectured by l. kauffman in @xcite. here   we show how a simple topological idea can yield a beautiful solution to what seems to be a complicated problem.
the standard model of the higgs boson suffers from the problem of quadratic divergences when radiative corrections, due to the loops of fermions, the top quark in particular, to the mass of the higgs boson are calculated.   this problem is often referred to as the hierarchy problem, as we require an artificial fine tuning between the induced radiative mass, which is of the order of the cut - off scale, e.g., @xmath9, and the counterterm to produce a mass on the electroweak scale, i.e.,@xmath11  gev. here   we show that these divergencies are proportional to the tadpole and therefore vanish when the vacuum is stable. using the top - quark mass as input, we also show that the goldstone bosons do not suffer from the same problem, and that the divergence of the weak current so that derivative couplings do not arise is independent of the physics that causes them.
the outflow dynamics of the molecular cloud into the hii regions around massive stars are of considerable interest because of their potential to play a role in star formation.   the shape of the surfaces between molecular clouds and these regions typically feature elongated structures, commonly referred to as pillars, columns, spikes, or elephant trunks. here   we discuss the formation mechanism of the pillars in m16, popularly known as the eagle nebula, which has three large, molecular pillars near a small group of o2 - 3 stars. using co line experiments, we show that the pillars are not in the same plane in the sky ; the differing signs of the velocity gradients indicate inclination towards ( positive gradient ) or away ( negative gradient ) from the observer. by using a model based on the rayleigh - taylor ( rt ) instability theory, we estimate the time scale of the nonlinear stage of the rt instability occurring at the contact discontinuity between the dense molecular cloud and the lower density, hot, photoevaporated plasma.see research article http://www.biomedcentral.com/1471-7007/1741-eagle-b nebula-2013-12-01
we study the behaviour of the time - integrated longitudinal magnetisation in the one - dimensional transverse field ising model ( tfim ) of the quantum ising chain @xcite.   we show that the static disordered phase of the tfim belongs to a @xmath0-symmetric regime, so that the cumulant generating function of the temporal transverse magnetisation is vanishing ( implying that all its cumulants are sub - linear in time ). in contrast, the static ordered phase belongs to an unbroken regime where the symmetry of the non - hermitian hamiltonian of the system@xcite is broken, and where thecumulants of the t1/t2 transitions grow superlineraly with time.
the crab nebula pulsar ( b0531 + 21 ) intermittently produces giant pulses ( gps ) in the frequency range 2084  mhz.   we report the detection and characterization of these pulses by the recently - completed long wavelength array station  1 ( lwa1 ) radio telescope in central new mexico. using a combination of high - signal - to - noise ratio detection and flux density calibration methods, we show that the observed gps are composed of nanosecond- and microsecond - scale impulses from the host nebula and the interstellar medium ( ism ) along the line of sight, and have an intrinsic duration of about 2.5  s. the pulse broadening of the pulsar's pulse is due to the galaxy and the ism along the lines of sight and is consistent with the existence of a strong interaction between the pulsary system and the surrounding interstellar medium at the time of peak emission.
we study high - frequency ( @xmath2 khz ) pressure oscillations ( p - modes ) localized in a thin neutron star envelope.   we use the relativistic cowling approximation of the equation of state of stelar matter and the newtonian hydrodynamic equations to study the effects of the neutron drip on the oscillation spectrum. using the space - time metric in the envelope as a plane - parallel layer, we find that the pulsar surface is covered by a thin layer of degenerate electrons and neutrons, which are largely independent of temperature. for the first time, we show that the density of ground - state and accreted matter in the inner envelope of the star affects strongly the amplitude of these oscillations. at densities of ~10 g   g1, the intensity of the oscillations decreases with increasing neutron drip point, and the rate of the decay increases with decreasing neutron drip. if detected, this spectrum would give valuable information on the internal structure of the envelope and also on the global parameters of neutron stars.
the formation of active regions in the solar convection zone is a well - known phenomenon.   the standard paradigm is that active regions form when a coherent flux tube from deep in the convective zone reaches the surface, typically modeled using the thin flux tube approximation @xcite. here   we show that the action of magneto - convection itself produces rising flux tubes, which when they reach the surface can produce an active region. as the magnetic field enters the computational domain, convective upflows immeadiately begin to drag portions toward the surface while convective downflows pull other portions down, thus creating magnetic loops. by taking advantage of the time - dependent nature of the process, we find that the size of the active region is not affected by the horizontal boundaries of the domain, because its size is 25 mm inside a 48 mm wide box, second, because it is spreading very slowly with time and, third, because the top boundary is close by ( at the temperature minimum ) so theagnetic field does not have room to spread out much in the atmosphere and interact with the mirror active regions produced by the vertical periodicity.
the resonant production of the susy particle through couplings is an attractive possibility which must be considered in the phenomenology of supersymmetry. at hadronic colliders, either a slepton or a squark   can be produced at the resonance respectively through a @xmath10 or a@xmath11 coupling constant.   however, for reasonable values of the coupling constants, the decays of the resonant scalar particle via gauge interactions are typically dominant if kinematically allowed @xcite. in this paper  , we study the single gaugino productions at teflon - yan ( te ) and hadronic ( had ) colliders using the r - parity violating ( ) extension of the minimal supersymmetric standard model ( mssm ). by means of the displaced vertex analysis of the lightest supersymmetrized particle ( lsp ) decay, we show that the main decay of the resonate scalar particles is the single gaugegino production, in case where the decay of its partner plus a gaugano is kinematic allowed.    the results are compared with the results of the previous studies of the sugra model and the grand unified theory ( gut )
in contemporary neural computing, an active branch of research is the nature - inspired algorithms with diverse applications in engineering optimization.   most of these algorithms are based on the so - called swarm intelligence, and usually involve some form of non - deterministic, stochastic components, which often appear in terms of random walks. in this paper, we introduce the random walks and lvy flights in the proper context of metaheuristic optimization, and use these results in the framework of markov theory to analyze the iteration process of algorithms such as step sizes, efficiency and the choice of some key parameters. using the eagle strategy ( es ) developed by xin - she yang and suash deb , we first introduce the fundamentals of random walk and discuss lvy flight random walks, as well as their links to optimization via markov chain theories. then, we present four case studies for engineering optimization applications that illustrate the advantages and disadvantages of different steps of the eagle method. finally, we briefly draw the conclusions in section 6.
cosmic shear is a simple statistic that measures the gravitational bending of light by all the intervening mass in the universe.   it is particularly simple if distant background galaxies can be assumed to have random orientations, which leads to two complicating effects : ( i ) neighbouring galaxies at a given redshift are intrinsically aligned and ( ii ) a pair of galaxies at two different redshifts have correlated observed ellipticities because a dark matter concentration close to the nearer galaxy may tidally align the nearer object and simultaneously gravitationally lens the more distant object. in this paper   we present another complicating effect which is much simpler than the intrinsic alignment effects : cross - correlation of a couple of galaxies with respect to each other at different Redshifts produces a contribution to the usual cosmic shear two - point correlation function even if there are no tidal effects. for elliptical dark matter halos for which mass and light have the same ellipticity and orientation,   this contribution is due to galaxy - galaxy lensing, which produces a net anti - correlation in the realistic case when the nearest galaxy is not circularly symmetric and has a correlation between the asymmetry of the light and the mass. using complex notation we
the process of stimulated raman adiabatic passage ( stirap ) is well known in three - level - optics, where it refers to the technique of applying a counter - intuitive sequence of laser pulses to achieve a transition of an electron between the two ground states in a @xmath0-system.   recently it was pointed out that systems consisting of three separated centre - of - mass modes allow for the use of stirap - like processes to achieve robust transfer of atoms from one position to another with high fidelity. in this work   we will focus on atom - chip systems and investigate their suitability to observe this adiabscent process. while the initial state for a numerical evolution can be prepared with a large degree of localisation, one of the problems following the subsequent evolution inside the waveguide is that the wavefunction disperses along the guide which makes it hard to exactly measure the final state of the system and put a quantitative number on the efficiency of the process. by using a simple harmonic potential along the longitudinal direction of the trap, we show that the resonance condition is fulfilled throughout the whole process and that the dispersion of the wave function in the lateral direction has no significant effect on the fidelity of the
the main objective of this paper is to present experimental results on an " one - way light path " laser diffraction experiment mounted in the shell of the tupi muon telescope @xcite and that shows clearly that the speed of light depends on the propagation direction.   the effect is observed as a amplified doppler shift in the diffraction images as function of the laser beam alignment relative to the earth s velocity vector.the experiment is an improved version about light diffraction suggested by c. m. g. lattes, and it is well described by the so called ether gauge theory ( egt ), which is an extension of the lorentz s ether theory. at the same time, the cosmological time boundary condition satisfies the robertson - walker - friedmann metric and leads naturally to a non - isotropic "one - way " light propagation relative to its earth frame and where there is a preferred direction. for instance, the origin of the newtonian space - time can be explained by the existence of a preferred reference frame created by the big - bang.
the galactic supernova remnant ( snr ) ctb  109  ( g109.11.0 ) was first discovered as an snr in x - rays with _ einstein _   @xcite and in radio in the 610  mhz galactic plane survey@xcite.   it has a semi - circular morphology in both the x - ray and the radio and is located next to a giant molecular cloud ( gmc ) complex in the west, which suggests that the snr shock has been stopped entirely by the gmc complex. for the first time we have obtained high resolution x- and co data at 45  resolution using the five college radio astronomy observatory ( fcrao ) 14  m antenna in march 2003. from the new data we show that the bright, extended interior region known as the ` lobe'is completely thermal @xmm - newton, and this could be the result of a hole in the g mc allowing the xray emission through with little or no absorption or it could be due to intrinsically brighter emission due to an interaction between the shock and the cloud.
we present our calculation of the ground state mg@xmath4 scattering length and cross - section as a function of the collision energy, using a potential constructed from high resolution spectra of the magnesium dimer measured by balfour and douglas @xcite.   the experimental data are compared with the theoretical calculations in the existing literature and a new multiconfiguration valence bond ( mvb ) calculation is presented. at temperatures below 5 mk ground statemg atoms are in the s - wave scattering regime and the _  = 0 phase shift determines the cross - sections and, at zero collision energies, the scattering length. for the most abundant isotopes of mg atoms the electronic ground state is solely composed of closed shells and is a @xmath3 state. to obtain the interaction potential we use a rydberg - klein - rees ( rkr ) potential curve that has been constructed from the measurement of the rovibrational levels ( @x Math5 = 0 - 12, @x maths6 = 10 - 76 ) of ground state md@x math4.. the density functional theory calculations of the rkr potential have been previously reported for mg@xcite and the inverted
galactic bars are dissolved in 14 gyrs in most galaxies, which we had attributed to the growth of a central mass concentration ( cmc ).   we show that the gas inflow in our simulations is initiated by gravitational torques, that are much larger than viscous torques. while most existing works had focused on the effects of the cmc growth, we show here that another phenomenon can also lead to the destruction of galactic bars in a few gyrs : the torques between the stellar bar and the gaseous arms also disturb the bar and can dissolve it. yet, even when the gas infalls and the effect of thecmc is correctly treated, the dissolution of the bar itself is not enough to completely destroy it.
we present a framework to manipulate and measure binary quantum information encoded in continuous variables using the formalism of modular variables ( mv ), which allows us to naturally identify discrete structures in continuous variable states.   we further introduce adapted operations and observables which enable us to manipulation and readout the encoded discrete quantum information in terms of the corresponding cv logical states. our results have immediate experimental impact which we demonstrate by applying them to the transverse degrees of freedom of single photons.
particle tracking velocimetry ( ptv ) is a method to measure particle velocities with video camera recording.   it has been widely used for many years in topics in various fields, such as cell motion in biology, flow in granular materials, and kinetic temperature in dusty plasmas. here  , we show that the accuracy of the velocity calculated using ptv can be affected by two kinds of errors : one arises from acceleration of the particle during the time interval between measurements of its position and the other from errors in the position measurements themselves. while the former is made less severe by using a faster frame rate, the latter is actually made worse. when determining kinetic temperature by calculating the mean - square velocity fluctuation for random motion, the result will have an exaggerated value that worsens at higher frame rates, due to one of the two types of errors studied here.
we present an algorithm for solving variational problems with convexity constraints.   this is based on the idea of approximating a convex function by an affine envelope, and is applied to a set of problems where the set of goods lies in an infinite - dimensional space, even when the agent types are one - dimensional. using the affine - envelope method, we find several variants of an algorithm that approximate the solution to the problem presented in @xcite, which is a well - known example of a risk - minimization problem under non - linear pricing.
the yokonuma  hecke algebras ( of type gl ), denoted @xmath1, have been used by j. juyumaya and s. lambropoulou to construct invariants for various types of links.   this study culminated in the recent discovery that these invariants are actually topologically stronger than the homflypt polynomial ( i.e. _ they distinguish more links ). in @xcite, another approach to study invariants coming from yokonsuma   heckel algebrae was developed via the isomorphism theorem. here   we sketch a short proof for @x math4, which is a new extension of the previous approach to link invariants using the isomorphicism theorem as a generalised form of the method used for@xcite.    our main goal here is to generalise for #@xmath4 the whole approach to linking invariants via the Isomorphism principle. 	 we show that the invariants obtained in @xaite from @x Math4 correspond to the invariant obtained in #@xcites from @exmath1.  also, we identify the juy
this article is a reprint of the original work by hiawatha, the famous chief of myth and legend.   the full text of the book can be found at http://www.biomedcentral.com/1471-7007/9/8.
the european space agency s @xmath4 mission @xcite has recently published its first data release, giving us a new window on our galaxy, and in particular the solar neighbourhood.   many aspects of the structure and dynamics of the milky way are difficult to measure, owing to our position within the galaxy, as well as complex observational selection effects such as dust extinction. with 6-dimensional phase space measurements for nearby stars   it becomes possible to calculate the tangential velocity distribution with respect to the sun, and thus we can test the prediction that the rotation velocity of the sun may be measured by searching for a dearth of stars around the assumed value of the negative of the solar motion. using the radial velocity experiment ( rave ) data from the tycho-@x Math4 astrometric solution ( tgas ), we find that there is a low - velocity tail of the velocity distribution which displays a clear dip in the range between @x maths18 and @x math19. here   we present simulated models which can explain the feature and make predictions for the size and shape of the observed feature. finally, we fit our model to the data and present our measurement of @xMath9.
the merger of two white dwarfs is one of the possible scenarios to account for several interesting astrophysical phenomena. in this paper   we show that the coalescence of two degenerate cores can also explain the presence of very high magnetic fields in some white dwarf close binary systems.   our model shows that the hot, differentially rotating, convective corona resulting from the merger produces strong magnetic fields, which are confined to the outer layers of the resulting remnant, and which do not decay for very long timescales.
in this paper we study the optimal stopping problems of conditional convex risk measures in an uncertain environment.   the classical solution to the problem assumes that there is a unique subjective prior distribution driving the reward process, but it is reasonable to view the multitude of possible distributions as a kind of model uncertainty risk which should be taken into account while formulating an optimal stopping problem. here   we focus on the problem of optimally stopping a reward process with respect to a nonnegative, right - continuous stochastic process under some lower semicontinuous convex mapping. for this purpose, we consider a rather general class of conditional risks having representation with @xmath29 $ ] for some lower semitendemic convex maps.. we find that the optimal solving of the problem is not always successful, as the probability measures are not always time - consistent and the penalty function scales the plausibility of the models.
the ultraviolet spectra of seven very hot hydrogen - rich central stars ( @xmath0@xmath170000k ) are analyzed using nlte metal line blanketed model atmospheres in order to determine temperature, surface gravity, and chemical composition.   the results show that the effective temperature of ngc1360 is lower than previously thought and that the iron abundance in the star is close to solar.
the modified newtonian dynamics ( mond ) is an empirically - based modification of oldtonian gravity or inertia in the limit of low accelerations suggested by milgrom ( 1983 ) as an alternative to cosmic dark matter.   although mond has been shown to be a powerful tool for explaining the kinematics of small groups of galaxies and of superclusters, problems do arise when one attempts to apply mond to the large clusters of galaxies. here   i consider the issue of the remaining missing mass in clusters and consider whether or not this is a fundamental problem for mond. using a sample of x - ray emitting clusters,   I find that the mass predicted by mond is typically a factor of two or three times larger than the total mass observed in the hot gas and in the stellar content of the galaxies. moreover, the radial dependence of surface brightness does not reproduce that typically observed in x -ray emitting clusters observations which are well - fit by the traditional   @xmath0-model ". with mond  , it is possible to estimate the mass of the central regions of the clusters without any additional non - luminous mass, primarily in the inner regions,
the abundance patterns of extremely metal - poor ( emp ) stars are useful in studying nucleosynthesis in massive supernovae ( sne ).   population ( pop ) iii stars are usually considered to be massive stars, but there are also emp stars with abundances of elements that can not be explained by the s - process or main r - process. here  , we propose a new model for the nucleosynthetic result of a pop iii sn which is based on the mixing - fallback model proposed by umeda @xmath6 nomoto ( 2002 ) ( hereafter un02 ) and wanajo & ishimaru ( 2006 ). using the model, we show that the abundance pattern of the elements from c to zn of carbon - normal empStars and carbon - rich emp Stars can be successfully reproduced by energetic core - collapse sn models or the imf - integration of hypernova and faint sn models, respectively, while those of very metal poor ( vmp ) emp Star(s ) can only be reproduced by normal core - collapsed sn models. however, there are some emp star(s) that require another neutron - capture process referred sometimes as " le
the evolution of a planet in close orbit around its parent star is strongly modified by strong irradiation from its star.   the correct description of these properties has been questioned recently by the detection of the transit planet @xmath0, and several authors have suggested that an important part of fundamental physics might be missing in the description of irradiated planets. in the present letter, the theory developed in baraffe et al. ( 2003 ) for non - irradiated and irradiated Earth - like planets is applied to various cases of hot - jupiters, with special focus on the case of the second observed transit,@xmath1. the theory adequately reproduces the observed mass and radius of the planet, for the proper age of the system and the more recent mass determination, and provides reliable guidance for future transit detections.
molecular polymorphism, the observation of different crystal structures made up of the same molecules, has been a central problem standing in the way of affordable and reliable crystal structure prediction ( csp ) which would greatly accelerate the development of new materials for applications in solid state chemistry, material science and pharmaceutical science.   the key challenges for ab initio csp of molecular crystals include the computational cost of thermodynamical exploration of a rich polymorphic phase space, the accuracy needed to resolve similarly - low energies among polymorphs @xcite, and the fact that kinetic factors may control the crystallization procedure rather than thermodynamic ones @xcites.. we have performed a fully ab initial csp search on glycine crystals, without semi empirical corrections in the energy description, using neither information on cell geometry nor the symmetry of the experimentally observed polymorphs. despite its rich polymorphism under ambient conditions,   only the @xmath1-glycine phase is found to be stable at 23  gpa, the highest pressure reached in experiments.    we show that even in difficult cases such as glycinestals, where polymorphs show energy differences as little as 1 kcal / mol, new non - local
the @xmath3 transition of water vapor, with a frequency near 22 ghz, was among the first masing transitions detected from an astrophysical source ( the orion molecular cloud ), and has proven to be an extraordinarily useful probe in environments as diverse as interstellar shock waves, circumnuclear gas in active galactic nuclei, and the envelopes of evolved stars.   the detection of multiple maser transitions has been crucial in elucidating the pumping mechanism responsible for the population inversions and the physical conditions in the masing gas. here   we review the recent advances in our understanding of the properties of the maser gas, and discuss the implications of these findings for the interpretation of maser observations.
weyl geometry is a new formulation of general relativity ( gr ) in which the length variation of vectors is not associated with any known physical field.   weyl s motivation was to geometrize electromagnetism, with the intend to unify it with gravitation, and the vector field that performs such a variation, which we will call @xmath0, is purely geometrical. in this paper   it is shown that the new geometric field does not give extra contributions to the trajectories of material particles and thus influences on an observable of the theory. from them, it is verified that the postulate that test particles travel through time - like geodesics should be different from the pseudo - riemannian case of general relativistic gr. as a consequence,   the gauge symmetry of the equations of gravity is preserved and the gravitational constant is found to be invariant under local transformations of scale.
reproducible research is fundamental for the field of microarray research as it will facilitate easy revision of papers, easy access to data and results, communication to other researchers and comparison between different methods.   this paper aims to make this task easier by providing a quick reference guide to the literature on the analysis of exon array data using the bioconductor package ` aroma.affymetrix ` ( http://www.aroma-project.org/aufh.org ) and its software @xcite. in this paper   we present a simple workflow for the statistical analysis of differential splicing and differential gene expression in ` r`/bioconductor `. with the help of sweave ( a tool for embedding ` r ` code in latexdocuments@xcite ), we show how to extract data for different statistical analyses and propose a method for gene annotation and for gene profile visualization. for this last step  , we use the packages ` biomart ` and ` genomegraphs ` to annotate and visualize the transcripts in a genomic context.
the so - called @xmath0-cdm cosmology, in which the universe is dominated by dark energy and cold dark matter ( cdm ), accurately describes the large scale properties and evolution of the cosmos. on the scale of the halos of large galaxies,   this model predicts copious cdm sub - structures, the most massive of which are identified with the dwarf satellite galaxies that are observed to inhabit such regions.   the aim of the present paper is to examine the validity of the recent analysis of the millennium - ii simulation @xcite, and to extend our earlier analysis to make better use of the accurate kinematic information available for the real satellites. using the data from the sloan digital sky survey ( sdss ) and the wmap year 7 analysis, we find that the distribution of dwarf galaxies within the local group is more complicated than previously thought, and that the spatial alignment of the satellites observed in the sdss images supports the results of the bb14 analysis.
a cooperative communication can provide more reliable communication by reducing the error probability, while the required power remains the same.   the concept of cooperation in the communication has a long history going back to @xcite where an information theoretic aspect view of cooperative communication in a multiple access channel ( mac ) is defined. in this paper, we propose a cooperative scheme based on a simple addition of the received signals in the relay node of a two - user multiple access relay channel ( marc ) in which the users send the log - likelihood ratio ( llr ) of their coded messages to the destination in a noisy channel, and after modulating the users re - encoded packets, the relay nodes simply add the packets for transmission in the relays.    we derive a tight upper bound on the bit error probability ( bep ) for both uncoded and coded transmissions, from which we show that using v - blast detection technique, we can achieve full - order diversity, being two in a two-user marc setting. moreover, results show that the proposed scheme can achieve a diversity order of two for any number of users and only one relay node, in contrast to the traditional methods ( e.g. alamouti
we present a set of algorithms for testing and learning from quantum and classical sources of information.   all of our algorithms are based on a quantum subroutine due to @xcite, which we will refer to as an @xmath2 ( fourier sample ) oracle call. in this paper  , we show that the number of oracle calls needed to test and learn from a given set of quantum examples can be minimized by using only uniform quantum examples drawn from a uniform distribution quantum example oracle. when the learning algorithm queries the oracle each time it receives a labeled example from a fixed probability distribution over the space of all possible examples, such examples can not efficiently simulate even classical membership queries in general. here   we give upper and lower bounds for a range of learning and testing problems related to boolean functions that depend only on ( an unknown subset of ) at least one instance of the boolean function @x Math16. with the help of the @x math2 oracle, we find that most of the tests and some of the learning problems can be solved without requiring any more than a few oracles.
smc 3 is one of the symbiotic systems in the magellanic clouds.   it contains a wd and an m giant with an orbital period of 4.5 years. because the system contains a massive white dwarf with a high accretion rate ( @xmath2  m@xmath1/yr ; kahabka @xcite ) with a steady hydrogen burning on the surface of the white dwarf it is considered as one ofthe most promising supernova ia progenitors among the known symbiotic population. to estimate the mass of the red giant we used the fact that it pulsates with a period of 110 days ( kahabski et al., 2012 ). for all of our models the system went trough a common envelope ( ce ) after @x Math7  yrs and for none of the models system wd managed to accumulate enough matter to become a type ia supernova. the orbital separation after the ce was relatively big ( a@x maths8r@x math1 ), which makes a merger in the hubble time unlikely.
this article proposes an approach to inferring the causal impact of a market intervention, such as a new product launch or the onset of an advertising campaign.   our method generalises the widely used difference - in - differences approach to the time - series setting by explicitly modelling the counterfactual of a time series observed both before and after the intervention. it improves on existing methods in two respects : ( 1 ) it provides a fully bayesian time -series estimate for the effect ; and ( 2 ) it uses model averaging to construct the most appropriate synthetic control for modelling the Counterfactual.. the ` causalimpact ` r package provides an implementation of our approach ( http://google.github.io/causalimpact/ ).
we study the expansion of two - component interacting fermions in a one - dimensional ( 1d ) lattice of an out - of - equilibrium cold atom gas, which is characterized by a tomonaga - luttinger ( tl ) state with power - law decaying correlations at any incommensurate filling.   we show that the expansion dynamics of the system, being either a mott insulator ( mi ) or to monte carlo state, depends on the initial state of the quantum gas. using the adaptive time - dependent density - matrix renormalization group method ( tdmrg ), we analyze the time - evolution of the density profiles and the momentum distribution function for both the tl and mi initial states. as a result  , we find that the latter is more strongly correlated than the former, while the latter exhibits a stronger spin - degree of freedom and a higher charge gap opening at half - filling compared to the latter. here, we provide evidence that correlations measured in nonequilibrium are quantitatively described by appropriately chosen equilibrium reference systems.
nonuniform growth is inherently present in a broad class of phenomena including the development of biological populations, communication networks or economic systems like incomes of persons or companies.   these models have been treated by different tools including simulations, continuum or mean field theories and exact calculations by which information has been accumulated about the asymptotic behavior and the time dependence of the global distribution functions. however, much less attention has been paid to the full time - dependent solution of the problem. in the present work   we give such a solution of a particular model where the attachment of a new entity to one of the existing groups depends on the already achieved strength or size of that particular group. for a growing system which consists of groups of different sizes at each time step we add a new element to the system and the probability that it joins the @xmath2-th group is proportional to the size of the group.the results show that the scale invariance of the system can be explained by the preferential growth mechanism.
we study the collapse of the baryonic gas in an einstein - de sitter universe, ignoring the gas initial temperature, cooling and heating processes.   we assume that the collapse initiates from a symmetric scale free density peak, and that the velocity of each shell in the peak is taken to match the general expansion of the universe. for any perturbation with an adiabatic index of @xmath2, we find similarity solutions in planar, cylindrical, and spherical geometries for the newtonian equations of motion governing the ad iabatic collapse of symmetric perturbations in a collisional fluid ( gas ) of ad = 0.1, 0.2, and 0.3, respectively. by using numerical integrations of the equations, we derive asymptotic behaviour of the fluid variables in a universe dominated by collisionless dark matter.
the effect of spin orientation of free carriers by a passage of electric current on the electron momentum - space distribution in noncentrosymmetric two - dimensional ( 2d ) systems lacking a center of inversion is studied.   the theory of the spin - orbit coupling between spin and electric current is extended to include the effect of the electron quasimomentum on the polarization of the induced spin in the electric field. for a weak electric field, the spin polarization can be increased by increasing the ratios @xmath10 and ( or ) from 0.1 to 0.5 in the range of 1.0 to 1.2  kv / cm2. for moderate electric fields, the ratio @x Math11 is much smaller and the spin behavior is more anisotropic.    the results are compared with the streaming regime for a degenerate electron gas with a strong electric field and with those for a system with a weak one.
strangeness production has been extensively studied in relativistic heavy - ion collisions.   its measurement represents an important tool to investigate the properties of the strongly interacting system created in the collision, as there is no net strangeness content in the initially colliding nuclei. in these proceedings   we briefly discuss the technique used to identify k@xmath0, and to measure their transverse momentum ( @xmath2 ) spectra at the alice detector at the laser hodoscopy center ( lhc ). then we describe the main results about baryon anomaly, strangeness nuclear modification factor and strangeness enhancement.
aging is a key aspect of the dynamics in a host of complex glassy systems.   its main characteristics are a slow, sub - linear drift of macroscopic averages with the age @xmath0 of the system, i.e.  the time elapsed after an initial thermal quench, and a concomitant age dependence of the correlation and response functions. adopting the simplified view that the selection is truly irreversible allows us to formulate a theoretical description of large non - equilibrium rearrangements, or'quakes ', which borrows from studies of non - thermal models  . the key feature is dynamical invariance to shifts in the _ logarithm _ of time, which implies that the time spent in thermally metastable attractors is power - law distributed with an exponents @x Math3 and @x math4.    these theoretical results are checked through extensive numerical simulations of short ranged spin glass systems. while direct experimental evidence is not yet available, possibly related large - scale irreversible rearrangement similar to quakes have recently been identified in aging colloidal gels   ( e.g., nanocrystalline colloidal silica ). here  , we discuss
a paradigm has appeared to emerge according to which black - hole binaries in the hard state show weak both compton reflection and associated fluorescent fe k@xmath0 lines, whereas seyfert-1 agns would universally show stronger reflection and strong and broad emission.   if this were correct, it would certainly be of importance for our understanding of the physics of x - ray sources in accreting compact objects. here  , we critically examine this paradigm based on available data. using spectra of 24 radio - quiet ( rq ) seyFert 1s, 4u 0241 + 61, a low - redshift agn ( @xmath1 ), and ngc 4151 contemporaneously observed by both and the osse detector on board of _ cgro_, we find that the strength of reflection is strongly correlated with the intrinsic spectral slope of the continuum spectrum. as a function of the intrinsic slope,   the strongest reflection is found in the mid - layer of the lac, where the effective area above 10 kev is much more accurately measured than in the top layer ; however, the latter shows a weaker reflection than the former.conclusionsthese results suggest that the
the gamma radiation due to excitation of @xmath2 nuclei by inelastic scattering of muon - produced neutrons received little attention in the past.   the goal of this paper is to identify characteristic @x Math2 gamma lines in background spectra registered by a iron - shielded hpge detector and to compare the relative intensities of measured gamma transitions with published results on the same gamma transitions detected in neutron beam scattering experiments. using@xmath4 source, we get the qualitative information about the average energy of muons - created neutrons in the iron shield and to infer relative intensity of gamma lines associated with scattering of Muon - induced neutrons and fission neutrons.    the results show that the mean energy of neutrons emitted after muon capture does not exceed several mev @xcite but the average energies of high energy muons are higher than those of neutral neutrons at the earth s surface. for incident neutron energies between 6.3  mev and 14.2  meV, relative intensity of observed gamma line changes by almost 80% @x math2.
inflation in the early universe is now an indispensable ingredient of modern cosmology not only to explain the global properties of homogeneous and isotropic space with a vanishingly small spatial curvature but also to account for the origin of the primordial curvature perturbation that seeded cosmic structure formation.   however, it is often claimed that, if one tries to discuss what happened before inflation and/or how inflation started, one needs to know the information of very high energy physics, and challenge the initial singularity problem @xcite in terms of quantum gravity. in this paper  , we take a different approach, namely, to make use of the galilean genesis to describe the initial condition of the universe before inflation.we construct a specific model free from any catastrophic instabilities and with subluminal velocities of primordial perturbations. in our setup   the universe starts from the minkowski spacetime from infinite past and is smoothly connected to the inflationary phase followed by the graceful exit. for this purpose, we provide a generic lagrangian capable of describing the background and perturbative evolution in all the above phases instead of choosing the effective field theory approach because the latter can
we propose a novel design of an array of silver nanobricks on top of a thin silicon dioxide platform, namely sierpinski carpet, which is capable of absorbing light in the visible spectrum ( @xmath3-@xmath4 nm ) with a simulated average absorption more than @x Math5%.   the proposed configuration consists of an arrays of silver nanoparticles arranged in a fractal - like pattern and covered by a thin metal - dielectric - metal ( mdm ) thin - film. using three - dimensional ( 3d ) simulations based on finite integration technique ( fit )  , we theoretically investigate the effect of propagative and localized plasmon modes and localized magnetic and electric dipole resonances on enhancing the efficiency of proposed light trapping structure. to achieve wideband, polarization insensitive, and angle - independent absorber over solar spectrum, we investigate absorption mechanism of an inspired fractal pattern, namely Sierpinksi carpet. due to the self - similarity of fractals, different scales within the same structure are replicated resulting in multiple - band spectral response which is useful for broadband applications such as multiband antennas @xcite. moreover, fractal structures might have a larger perimeter
neutrinos have masses, the tiny masses far below the range of the masses of the quarks and charged leptons.   maybe due to the non - zero masses, neutrinos oscillate among themselves, giving rise to a lepton - flavor violation ( lfv ). in this note,   i wish to point out that the cross - generation or off - diagonal neutrino - higgs interaction may serve as the detailed mechanism of neutrini oscillations, with some vacuum expectation value ( vev ) of the new higgs field(s ).
the sdss is a large - scale, public domain project to survey the northern galactic cap ( @xmath4 square degrees ) with a dedicated 2.5 m telescope at apache point, new mexico.   we have developed a repository of software engineering tools that are entirely public domain ( with the exception of compilers ) and adopted as a source code manager. since july 1998  , we have acquired 1799 entries in the database ; the last thousand have been filed since february 2000. during this time   there have been about 1.7gby of updates to our cvs repository, which we have used as a problem report and bug database for the sdss data collection and analysis.
the computational effort needed to deal with large combinatorial structures considerably varies with the task to be performed and the resolution procedure used.   the worst - case complexity of a task, more precisely an optimization or decision problem, is defined as the time required by the best algorithm to treat any possible inputs to the problem. in this paper   we will present an overview of recent works done by physicists to address this point, and more precisely to characterize the average performances, called complexity, of a given algorithm over a distribution of inputs to an optimization problem.
we show that excited many - particle states of a laser - driven gas of rydberg atoms on a ring lattice can be obtained analytically in the limit of strong laser driving.   we give a detailed derivation of the system s hamiltonian and analyze the construction of the many - body excitations, their eigenenergies and their correlation properties. to obtain these states we assume that the external dynamics of the atoms to be frozen, i.e., no hopping and hence no particle exchange between the lattice sites is present. using this assumption, we study the excitation dynamics of a gas of bosonic ground - state atoms confined to a deep large spacing optical or magnetic @xcite ring lattices with periodicity. by taking advantage of the unique properties of highly excited atoms, we show that they can be excited in a short time scale in the presence of a strong laser field reads. as a result  , we find that the number of atoms in the excited state increases with the distance from the ground state to the laser field reading. for each atom in the x- and y - state, the electronic levels of the excited states are well isolated from any other electronic level.
loop quantum cosmology ( lqc ) has become an interesting candidate for a quantum description of the early universe via homogeneous cosmological models.   based on the same quantization methods of loop quantum gravity @xcite, it has also become a testing ground for different conceptual and technical issues that arise in the full theory. here  , we explore the new connection based quantum theory for a spatially flat @xmath0=1 frw model coupled to the simplest kind of matter, namely a mass - less scalar field that serves as an internal time parameter. by means of an effective description of its dynamics, we show that the corresponding cyclic universe undergoes a series of bounces and recollapses, but now _ there are two different kind of bounces. in the cosmic evolution, the universe alternates between these two bounces where both the density and minimum volume differ. interestingly, for universes that grow to become ` large ', the energy density of the first bounce is always lower than that of the second bounce, while the minimum volume of the latter is always higher than the original one. this result is consistent with the results of the standard holonomy based loop quantization explored in @xaite, where the
the ellis wormhole is a spherically symmetric solution of einstein equations with a ghost massless scalar field.   it is a potential target for probing by using gravitational lensing phenomena. in this paper  , we propose a way to probe elliswormholes by using lensed spectra of astronomical sources. in order to fully investigate the lensed spectrum of a point source, the wave effect in gravitational Lensing must be taken into account. in the geometrical optics limit, we consider light rays emanated from the source. since the light ray which is deflected once at @xmath19 can be regarded as the closest approach of the light Ray, the deflection angle @x Math20 is given by @x math21.. as a result, we calculate the amplification factor of gravitational lensation by the ellis worms by taking the wave effects into account and find the possible observations to probe these wormholes.
damped ly@xmath1  systems ( dlas ; *??? ) are gas with a non - negligible angular momentum that forms disks in the local universe.   these disks are mapped in the 21 cm line with radio telescopes and can be studied statistically through the observation of thousands of quasars across the sky. in this letter, we report on the results for a survey of the sdss data release 5 ( sdss - dr5 ; *????)we place new constraints on the projected column density distribution, total covering fraction, and integrated mass density of disks at @xmath13 and search for evolution in these quantities from @x Math14 to 4.    we also compare the measurements with disks from the local Universe @xcite.. these results offer new insight on the evolution of disks and their role in the processes of galaxy formation.
the weak coupling limits of gravity and gauge theories can be understood in terms of their weak coupling limit.   this relationship is particularly strong for quantum chromodynamics and supersymmetric gauge theories, which are both based on the idea of lorentz symmetry. at the semi - classical level,   the kawai, lewellen and tye ( klt ) relations hold that the amplitudes of quantum loop - level interactions in gauge theories must be expressed as sums of products of those of non - abelian gauge theory scattering amplitudes. to exploit the klt relations in perturbative quantum gravity, one needs to reformulate the quantization process ; the standard methods starting either from a hamiltonian or a lagrangian provide no obvious means of exploiting them. here  , we review the use of the @xmath0-dimensional unitarity method to obtain the quantum loop contributions directly from the tree - level amplitudes in quantum gravity. using this method, we show that it is possible to obtain collections of quantum loops - level feynman diagrams without any direct reference to the underlying lagrangians or hamiltonians. by doing so, we demonstrate that the weak coupling limiting of gravity can
experiments on single photons coupled strongly to single ( artificial ) atoms @xcite allow for in - depth studies of photon - atom interactions on a single particle level.   the coupling mediated via virtual resonator photons allows for a long - range interaction between two or more distant superconducting qubits. in this paper   we measure the exchange coupling as a function of detuning of two qubits from a single or multiple resonator modes and characterize the symmetry properties of the coupled system by measuring the spectroscopic measurement of the coupling near a single resonator mode. using a combination of quantum electrodynamics and quantum mechanics  , we show that the coupling strength of the qubit - resonator interaction depends on the distance between the qubits and the resonance frequency of the transmission line resonator. when the coupling is stronger than the detuning strength of both qubits to a single cavity mode, the qu bits can be used to form a dark state at the avoided level crossing and the observation of a two - photon transition from the ground to the doubly excited state that is allowed only at qubit resonance is made.
the generalized master equation ( gme ) is used to study the transport properties of a quantum wire in a turnstile regime.   the model is a parabolic lateral confinement model of a two - dimensional wire of length @xmath0 parabolically confined along the@xmath1 direction and with hard - wall conditions at @x Math2.    the leads are semi - infinite and extended from @x maths6 to @x math7, and from ~xmath8 to ~Xmath9.. the sample is connected to the source probe by a tunneling barrier between the left and right leads and the drain contact is closed on the first half - cycle. on the second half-cycle the source probes are disconnected, the drain contacts open, and the discharge of the dot follows. using the gme method   we find that the transport of electrons through the wire can be performed in the presence of a magnetic field in both the case and the absence of one.
galactic globular clusters ( gcs ) are dense and old stellar systems.   their study is crucial to understand the dynamical evolution of collisional systems and the interplay between dynamics and stellar evolution. in this respect,   remarkable is the case of m71, a low - density gc located at a distance of about 4 kpc from earth. here   we present the determination of : ( i ) the stellar proper motions ( which allow us to distinguish cluster members from galactic contaminants ), ( ii ) the absolute pm of the system ( from which we estimate its orbit within the galaxy during the last 3 gyr ), and ( iii ) the cluster gravitational center and structural parameters using two epochs of observations obtained with the hubble space telescope ( hst ) and wide - field near - infrared and optical datasets for m71. by taking advantage of the new values of the cluster structural parameters and the initial mass estimate, we show that the number of x - ray sources in m71 is significantly larger than what is expected from its present - day mass and its collisional parameter.
we discuss the possibility of using supersymmetry to explore the universe beyond the standard model.   we assume that the halo of palomar 13 is made of neutralinos and calculate the flux in high energy @xmath4-rays due to their annihilation at 25 gev in 400 h. these fluxes are not out of reach but ground - based ongoing instruments will have to be improved by one order of magnitude for that purpose.
the second nearest type ia supernova ( sn ) discovered in the digital era, sn  2011fe/ ptf11kly ( @xcite ), is a circumbinary progenitor of the recently discovered sn2011fe at @xmath12 mpc.   we report a detailed panchromatic study of this sn bridging optical / uv and gamma - ray observations with the swift and chandra satellites as well as the interplanetary network ( ipn ). using a self - consistent characterization of the shockwave and the x - ray emission in the month following the explosion, we show that the object appears consistent with a " normal " sn ia. by combining data from the swift satellite and the ipn, we provide deep limits on the density of the bulk ejecta and the mass loss rate of the progenitors companion, and for the shock breakout pulse. these limits are used to construct a model of the evolution of the accreting white dwarf ( wd ) in a single - degenerate or double degenerate model of sn   2011fe.
the veritas project is a multi - telescope project to detect gamma - ray sources at high elevations in the southern arizona sky.   the first of the four veritas telescopes has been in routine operation since january 2005 at the basecamp of the fred lawrence whipple observatory at mt.   hopkins, ari Arizona. for the following comparison of data with monte carlo simulations, gamma-ray candidates are extracted from observations of the crab nebula ( 3.9 h on source ) and mrk 421 ( 4.2h on Source ) in march and april 2005 using standard second moment analysis @xcite. as part of the simulations,   primary gamma - rays are simulated with a crab - like spectrum in an energy range from 10 gev to 10 tev on a circular area at the ground with radius 450 m. the response of the photoreceptors to single photons is simulated by adding up single photo - electron pulses with appropriate amplitude and duration based on measurements of the reaction rate of the pmts at the current site of telescope 1 and the final one at kitt peak.    the results show that the simulation results are in good agreement
the rave survey is a magnitude - limited survey of stars randomly selected in the southern celestial hemisphere.   it has collected 574 630 spectra for 483 330 unique stars, 425 561 of these targets are included in the latest release of the dr4 data from the australian astronomical observatory s uk - schmidt telescope in siding spring, australia ( kordopatis  2013a ). here   we review the current state of the rave survey and discuss its potential role in the preparation of the gaia era.
the astro - f ( murakami 1998 ) is the second japanese space mission for infrared astronomy.   the new infrared survey by astro-f will serve as valuable input catalogues for large - aperture space telescopes such as first ( pilbratt 2000 ) and also for 810  m class ground - based telescopes. in order to reduce the total weight of the cryostat, we have employed a hybrid cryogenics design ; the telescope and focal plane instruments are to be cooled by liquid helium with the help of mechanical cryocoolers, and the expected temperature is 5.8  k. the far - infrared surveyor ( fis ) instrument will perform the all - sky survey with 4 photometric bands at the wavelength range of 50  200 @xmath0 m using two - dimensional ge : ga detector arrays.
the bose - einstein condensation ( bec ) of composite bosons in ultracold fermi gases is a crossover between the bardeen - cooper - shrieffer ( bcs ) formalism and the schrdinger equation for the molecular state corresponding to the composite boson.   the theoretical treatment of this crossover has not been solved exactly and one has to rely on various approximate schemes, the simplest being the straight bcs formalism which is known to give a correct description at zero temperature in both the extreme bec and bcs limits. here   we review the experimental realization of the bec - bcs crossover through feshbach resonance experiments in the case of cold gases, where the dimer - dimer scattering length is related to the fermion scattering length. by means of the gross - pitaevskii equation from the bcs ansatz, we show that the critical temperature of the ideal bose gas of dimers is recovered in the strong coupling limit, while the dissociation energy of the dipole is conserved in the weak coupling limit. as a result, the cosmological behavior of the interaction between the two fermions is fully described by the direct sch
the public goods game is a typical example of an evolutionary game that is governed by group interactions.   the central theme of evolutionary game theory is the successful evolution of cooperation, and the concept of cooperation has been the subject of considerable attention in recent years as it has been shown that humans cooperate much more in such situations than expected, and in so doing these experiments call for the identification of mechanisms that can explain the successful development of cooperation. here   we review the current state of knowledge on the mechanism of cooperation in the public goods games, and discuss the implications of the emerging " stick versus carrot " dilemma.
we study the classical and quantum signatures of chaos in a square billiard rotating about one of its corners.   we study poincar surface of section of classical phase space and show that this system goes from regular to chaotic with change in rotational frequency. for larger values of parameter @xmath2,   the system exhibits more regular behavior. as the value of @x Math2 decreases, the chaotic region in phase space increases.the signature of the onset of chaos can be seen in the nearest neighbor spacing ( nns ) distribution calculated for the first 1000 energy levels of the system. for intermediate values of @Xmath2 it is seen that with small rotational perturbation, small kam islands form near the points satisfying nonlinear resonance conditions.    as the perturbations increase with decrease in parameter @ xmath2 however, the number of kam Islands decreases and the chaotic area increases. also, the time reversal symmetry breaking is revealed by wavefunction statistics.
the proposed advanced cosmic ray composition experiment for space science ( access ) mission @xcite requires a transition radiation detector ( trd ) capable of measuring the energies of cosmic rays up to 100 tev / nucleon for particles with charge.   such experiments require that the range of existing trds must be extended by an order of magnitude or more, requiring designs modified for use at these higher energies. in this paper  , we describe a new design for a thin radiator - type trd suitable for use in space - borne cosmic ray experiments using a nonzero conductivity interface between two materials with different dielectric constants and a plasma frequency. as the particle energy increases, the total radiated intensity increases up to a lorentz factor above which saturation sets in due to interference effects from the superposition of the amplitudes produced at each interface, resulting in pronounced minima and maxima in the spectrum, with the last ( highest frequency ) maximum near the surface of the detector where the effective plasma frequency is 1 for a metal and 0 for a nonconductor.
we report the discovery of 345s pulsations from the source saxj0103.27209  during a _ beppo_sax  observation of the small magellanic cloud ( smc ).   the observations were carried out by the narrow field instruments on board the  beppo-sax satellite and the medium energy ( mecs ) and low energy ( lecs ) instruments of the European Space Agency ( eso ) in 1998 july 2627, with an effective exposure time of 40320s. using data from the mecs and lecs, we find that the source is a persistent x  ray pulsar with moderate variability ( within a factor of 510 ) which is located near the optical limb of the supernova remnant snr010172.4.    we also report the results of the timing analysis of a recent public public public _   chandra  observation and discuss optical observations carried out at eso.
photonic crystals and optical lattices are periodic arrays of dielectric media in which light propagates linearly in various ways, depending on the geometry of the system.   both systems share important properties, namely the band structure of their energy spectrum as well as the possibility of producing confined and extended modes of light in photonic crystals ( @xcite ) and of matter in optical lattice@xcite. however, there are important physical differences which render each system unique : interaction between atoms in optical crystal lattices has led to research into the nature of nonlinear matter waves in these systems, revealing a vast spectrum of non linear behaviour. by contrast, light waves in photonics crystals obey maxwell s equations and, hence, always satisfy the superposition principle.. it is of conceptual importance to understand how light and matter waves at the same level in these two systems are comparable, and to investigate the possibilities of using the light fields in Photonic crystals to control the matter waves that are embedded in them. in the present paper,   we focus on two interesting connected possibilities : first, one particular type of wave manipulation, ie the generation of confined modes produced by defects in both periodic structures ; and second, the propagation
speden is a computer program that reconstructs the electron density from the diffraction patterns of individual particles.   it is based on the iterative hybrid input - output version of the gerchberg - saxton - fienup ( gsf ) algorithm, which has been used recently to reconstruct the density of single biomolecules from experimental x - ray diffraction data. in this paper  , we describe the development of speden, and its application to the reconstruction of scatterers from three - dimensional diffraction images of single bio - molecules. for each particle,   the pattern is classified into a number of mutually exclusive classes and the images within each class are averaged and the class averages assembled into a three -dimensional diffraction pattern by finding their mutual orientation relationships. using the method described in this article, we show that speden can be used to obtain high - resolution reconstructions of the electron densities of single biological particles from their diffraction profiles.. the software is freely available at http://www.bioinfo.stanford.edu.au/speden/.
we study the case of a central source having a quadrupolar structure as described by the erez - rosen solution.   this is an exact solution to the vacuum einstein s field equations which generalizes the schwarzschild spacetime to the case for a gravitational source endowed with an arbitrary mass quadrupole moment, and hence it is specified by two parameters : the impact parameter of the photons emitted from the central source and the effect of the strength of the radiation field on the energy distribution of the center of the system. in order to study the effects of the x - ray variability in the active galactic nuclei ( agns ) and the disc emission lines, we have taken into account the presence of a quantum gravity field that is generated by the accretion of test particles onto black holes or black hole spacetimes. under these conditions,   the spin of the test particle is proportional to the number of times it has been moved on the symmetry plane, and the critical radius at which it is attracted to the central sources is determined by the influence of the photon pressure on the eddington sphere. using the rauber - robertson model, we find that the dependence of the critical
the dimension 2 gluon condensate in pure yang - mills theory has been investigated in different ways since @xcite.   recently, chernodub and ilgenfritz have considered the asymmetry in the dimension twocondensate.    they performed lattice simulations, computing the expectation value of the electric - magnetic asymmetry for the gauge operator @xmath0 in landau gauge. at zero temperature,   this quantity must of course be zero due to lorentz invariance. at higher temperatures, however, it decreases and becomes negative when @x Math9 is reached. in this paper   we extend the computations in order to include finite temperature effects, with the aim of shedding more light on the results of@xcite.we find and discuss the minima of the potential, the values of the different condensates and their temperature dependence.
the rsp game is a game where players take their move simultaneously, each choosing a hand from the rock, the scissors and the paper.   the cyclic strength relation of the three hands determines the win and the loss. in the present study  , we propose a model of the rspgame on lattices that assumes that each player on a lattice point chooses the next hand from its neighbor with the maximum point. by considering the triangular lattice, the square lattice and the honeycomb lattice as examples,   we show that the spatial pattern with vortices and sinks appears as a coexisting steady state on the triangle lattice ; the vortex pattern is due to the frustration of this lattice.
we show that the spiral - spin ( sp ) state is eligible as the ground state in the hubbard model when the fully - polarized ferromagnetic ( f ) states are the ground states.   we check this for one - dimensional ( 1d ) @xmath2-@xmath3 hubbard models with infinitely large coulomb interaction taken as a typical example and calculate the energies of the sp and f states as a function of the inverse system size with the density matrix renormalization group ( dmrg ) method. by calculating the difference in the total energy between the sp state and the f state, which is the degenerate energy for the sample size, we show that ( i ) the spState possesses a kind of order parameter, ( ii ) although the state does not break the global su(2 ) symmetry in the finite system, it does so in the thermodynamic limit by making a linear combination of other states that are degenerate in that limit, and ( iii ) the spin - spin correlation length is larger for the spstate than for the fstate.    these properties can be exploited to determine the magnetic phase diagram from the calculation of the total spin of the finite - size system in
the large hadron collider ( lhc ) at cern will open a new frontier in particle physics due to its higher collision energy and luminosity as compared to the existing accelerators. among them   are the standard model ( sm ) higgs boson, supersymmetric ( susy ) and other new particles beyond the sm.   all of them can have masses in a very large range up to the tev scale. for many of these new particles,   the significance calculation in searching for and observation of a physics signal with known location and shape is no longer valid when either the location or the shape of the signal is unknown. here  , we describe a new analysis method and compare it with the current " sliding - window " approaches following these procedures.
a new two - dimensional ewald method for computing long - range interactions in infinitely periodic systems is proposed.   the method is based on a convergence - factor technique that combines the basic coulomb pair interaction with a dipole - moment dependent constant to obtain a conditionally convergent summation of the fourier potentials in the three spatial dimensions. by using this method,   it is possible to simulate charged and polar molecules embedded in a slab in which the particle supersystem is periodic in only one or two of the three spatiotemporal dimensions because of the breaking of spatial symmetry.
the existence of tidal tails surrounding globular clusters ( gcs ) in the milky way is well established.   the present work by @xcite and colleagues gives evidence of the existence of a tidal stream of stars emanating from the outer part of the palomar 5 globular cluster and covering an arc of 10 degrees on the sky, corresponding to a ( projected ) length of 4 kpc at the distance of the cluster @xmathite, obtained in the framework of the sloan digital sky survey. for this cluster  , we have detected a continuation of pal 5 s trailing tidal stream out to almost 19 degrees from the cluster. combining this with the already known southern tail of Pal 5 yields a stream some @x math6 kpc long on the night sky.. the results of this study are discussed in the context of the recent findings of the so - called sagittarius stream, which emerges from a dwarf galaxy that is currently being accreted by the Milky way.
we analyze the relation between black hole mass and bulge velocity dispersion in the kauffmann & haehnelt 2000 ( kh2000 ) model of galaxy formation and evolution.   we find a surprisingly tight correlation between the masses of supermassive black holes and the velocity dispersions of the bulges which host them, with a slope of @xmath4.1 dex and a scatter of only 0.3 dex based on a sample of 26 galaxies, including 13 new blackhole mass estimates derived using hubble space telescope spectra. this relation is well reproduced in the hierarchical growth of structure of cold dark matter - like cosmogonies, and strengthens theoretical arguments that spheroid formation and the growth of black holes are closely linked.
we compute the scaling dimensions of an interesting class of disorder operators in conformal chern - simons - fermion theories coupled to matter.   we find that the lowest - dimension disorder operators with @xmath5 units of magnetic flux have dimension where @x Math6 is the yang - mills - regulated cs level, and that this result is valid at all t hooft couplings. by computing the thermal partition function of all cs - fermanion states with a given magnetic flux on a two - sphere, we show that these operators are local operators that create magnetic flux in a theory with gauge group @x math8.    we also show that the thermal partitions of all x - ray boson states created by such operators at @xMath6 are the same as those of x - raman monopoles in four spacetime dimensions, and we discuss implications of our findings for the bosonization duality between cs -fermion and cs - boson theories.
the pf131010 ciechanw fireball was observed over central poland on 15 february 2013 at about 03:20 utc 17-meter asteroid entered the earth s atmosphere and exploded while travelling at a speed of 19 km / s.   the body became a superbolide meteor, which was seen over the southern ural region. in this paper   we report an analysis of the multi - station observations of the @xmath0 magnitude fireball made by cameras of the _ polish fireball network_. both the trajectory and orbit are calculated indicating that the fireball was related to 2010 tb54 asteroid. even closer resemblance of orbits is found for 2010 sx11 asteroid.
the kinematics of geodesic flows in five dimensional warped bulk spacetimes with and without branes are investigated.   the raychaudhuri equations are used to study the evolution of these congruences, which are characterised by three kinematical quantities : isotropic expansion, shear and rotation ( henceforth referred to as esr ) @xcite, which evolve along the flow according to the rayshow equations. for a single brane scenario or from a purely higher dimensional bulk perspective, the space - time dependence of the metric function(s ) associated with the extra dimensional coordinate(s)s basically imply that the scale of the extra dimension depends on the on - brane ( four dimensional ) spacetime coordinates. except for a brief discussion on randall  sundrum ( rs ) type models  , we shall, in this article, mostly work with the single Brane scenario and a five dimensional bulk.
we propose a new approach to free - space detection for advanced driver assist systems ( adas ) based on a fully convolutional network ( fcn ).   the fcn is trained in a self - supervised fashion using weak supervision, where it is trained with a limited set of training labels and then used to classify the images into two categories : image - level segmentation and scene labeling. by combining the two types of training methods,   we show that the proposed framework outperforms the current state - of - the - art algorithms for free - time detection of objects and other information about the surrounding drivable space.
the concepts of observability and controllability of discrete - time systems have been characterised by criteria mutually independent, but, in this work, it is demonstrated that, if certain conditions not very restrictive are imposed on the continuous system, then the characterisations of these concepts for the discrete system can be unified.   a joint characterisation of both internal properties is presented.. the control of the observability of a discrete system depends on the control ( observability ) of the continuous - time system, plus some additional conditions on the sampling sequence. as a consequence,   the problem of observing the state of any minimal realisation by means of the sampling can be reduced to the task of solving a system of linear equations. an adequate choice of the random sampling instants guarantees the compatibility of the system.
we study the thermal monopole properties in the quark - gluon plasma phase in the maximally abelian gauge ( mag ).   the results are based on numerical investigations of the euclidean monopole trajectories wrapped around the temperature direction of a volume at high temperatures. for the density of the monopoles in the minkowski space, we find that the density is independent of the lattice spacing, as it should be for a physical quantity and the density  density spatial correlation functions are computed in terms of the absolute value of the wrapping number of the monte carlo number of monopole pairs. to study the effects of the relaxation algorithm applied in the mag on the results, we have used the molecular dynamics algorithm to fix the gauge parameters of the binding of the thermally wrapped monopoles to the magnetization constant of @xmath1. using this method,   we have found that the values of the magnetic coupling constant for the two types of monopoles which wrap more than one time around the time direction are significantly higher than those for the ones which wrap only once around the timescale of the time directions. by combining the results from the previous studies with the results of the molecular
the relationship between the period - luminosity ( pl ) relations of classical cepheids and the distance of external galaxies observed with the hubble space telescope ( hst ) has been extensively studied in the last decade.   the theoretical explanation for the observational evidence of a pl relation for classical cetheids relies on the assumption that intermediate mass stars undergoing central helium burning are characterized by a mass - luminosities relation, as predicted by stellar evolution models. however, the universality of the cepheid pl relations is still under debate, and, in turn, the possibility of applying a large magellanic cloud ( lmc)-based pl relation to external galaxies can not be ruled out. here  , we compare the results of the hst key project @xcite and the recently published distances based on the tip of the red giant branch ( trgb ) method for a selected sample of spiral galaxies obtained from the same region of the universe using a series of spectroscopic abundances of metal - rich and metal - poor cep heptheids, and show that the metallicity correction to the predicted distance moduli varies with the assumed @xmath8, showing a sort of turnover around solar
we study the resonant conversion between cosmic microwave background ( cmb ) photons and axion - like particles ( alps ) in the presence of primordial magnetic fields.   we derive the analytical form of the resonanceant conversion in both strong and weak coupling limits, and evaluate the feasibility of future constraints from pixie / prism on the concomitant photon - alp mixing constraint from the far infrared absolute spectrophotometer ( firas ) data of the cosmic background explorer ( cobe ). for small - mass alps, we extend the constraint to smaller alp masses, @xmath12  ev, and show that the current constraints are not sufficient to constrain them independently of their couplings to the visible sector. when the coupling to photons is present, such alps can go through resonant conversions with cmb photons due to plasma effects in the cosmic dark age and be constrained independent of their contribution to dark matter.
abstractthe hard x - ray component of bursts from magnetars is an extremely hard photon index above @xmath110 kev in persistent emission spectra of a significant fraction of soft gamma repeaters ( sgrs ) and anomalous X - ray pulsars ( axps ).   the hard x-ray component is thought to be distinct from the blackbody - like soft component, which can be reproduced by a power law ( pl ) model with an extremelyhard photon index of@xmath19. here  , we show that the hardness ratio between the hard and soft luminosities on the characteristic age of the bursts from sgr0501@x Math04516, detected by suzaku ( @xcite ; paperii ; @xaicite ) and swift ( @xaix ), is significantly higher than that of the soft component. for this reason, we propose a photoelectrically absorbed two - blackbody ( 2bb ) model for the hard part of the burst, which is consistent with the results of recent studies using integral ( e.g., hete-2 ; @xcites ) and suzaki ( @xeix ) spectroscopy.
we study a thermostated harmonic oscillator described by a second order langevin equation.   we experimentally search for the fluctuation relations ( frs ) for the work done by an external operator and for the heat dissipated by the system, and present analytical derivations of fts based on experimental observations. in the present article  , we show that the temperature of the system is a good predictor of the fluctuations of the work and the heat.
the formal expressions of equilibrium statistical mechanics strictly apply only to ergodic systems that are in thermodynamic equilibrium.   thus these expressions only strictly apply to systems which are at the global free energy minimum given the system hamiltonian and the macroscopic thermodynamic state variables ( number of particles, temperature and pressure or density ). for such systems gibbsian equilibrium statistical mechanical provides an exact prescription for how to calculate the various thermodynamic quantities @xcite. however, these prescriptions are routinely applied to systems not in true thermodynamics equilibrium ( for example to metastable liquids, glasses, polymorphs and allotropes ). in this paper   we provide a statistical mechanical theory of time independent, nondissipative, nonequilibrium systems based on the fact that these systems are nonergodic and individual sample systems comprise er Gododic domains that do not span all of phase space. using molecular dynamics simulations on a model glass former, we show that the resulting statistical mechanical formulae are satisfied within empirical errors. by applying the transient fluctuation relation to finite thermodynamic quenches ( in temperature or pressure ) for such cases, we demonstrate that the boltzmann weights within the phase space domains and the robustness
the effects of metal cooling and chemical enrichment by feedback on galaxy growth and cosmic supernova ( sn ) history are investigated using a series of cosmological hydrodynamic simulations with and without metal cooling.   the results show that metal cooling increases the efficiency of galactic fusion ( sf ) and decreases the rate of star formation in the metal - enriched interstellar medium ( ism ). however, the effect of sn feedback on the sf efficiency is not well understood because the feedback process is highly nonlinear, and it is not clear whether the net effect of feedback and metal cooling would be negative or positive. to address this issue,   we have used a simple two - way interaction model to investigate the effects of metals on the energy / momentum interactions between the igm and the ambient gas. for the first time  , we show that the influence of metal heating on the equilibrium temperature of the ism is independent of the amount of oxygen in the gas, and that the increase in the mean molecular weight of the gas can be explained by the enhanced cooling rate by sn feedback. furthermore, we find that the total cooling rate of the primordial gas is significantly enhanced relative to that of the interstellar medium by the atomic emission lines
we study the coalescence of two spinning holes with zero initial linear momentum.   we use the teukolsky formalism, in which the spacetime of a black hole collision is represented as a single distorted black hole and evolutions are done with simple linear perturbative equations. to obtain the results for the inspiral of spinning holes, one can simply do a linear superposition of these results with those from our past work @xcite. here  , we present two cases that are exhaustive : ( 1 ) when the two spins of the two black holes are equal and opposite and aligned along the common axis of thetwo black holes, and ( 2 ) when they are parallel and anti - parallel to the common axes of theTwo Black Holes.
the phase field crystal ( pfc ) equation is a conservative form of the familiar, non - conserved, swift - hohenberg ( sh ) equation.   it is a model that has generated considerable recent interest because it captures features at the atomic scale, and thus contains highly detailed physical information about the system s structure. in this manuscript   we develop a class of unconditionally stable time stepping algorithms ( @xmath3 taken arbitrarily large without the solution becoming unstable ) to solve the pfc and sh equations. using this algorithm, we show that the cahn - hilliard ( ch ) equation can be driven by an accelerated algorithm, with the accuracy in correlation controlled by@xmath5. for the allen - cahn ( ac ) equation,   the performance of the accelerated algorithm is comparable to that of the conventional euler discretization.
early - type galaxies in clusters exhibit a linear color - magnitude relation indicating that bright galaxies are systematically redder than their faint cluster companions.   this relation shows very small scatter ( @xmath3 magnitude ) in high precision photometry of local clusters such as coma and virgo and can be extended to clusters at medium - to - high redshift (@xmath4 ). here   we present a new, more model - independent approach for evaluating the full range of ages and metallicities allowed by the spectro - photometric properties of early - type galaxy in clusters. using the latest version of the bruzual & charlot models of stellar population synthesis, we construct age - metallicity diagrams constrained by the colors of early-type galaxies in the nearby coma cluster and in 17 clusters observed with the _ hubble space telescope _ ( _ hst _ ) at redshifts up to @x Math5. from these diagrams, we compute the corresponding ranges in mass - to light ratio and in several commonly used spectral indices.. the results show that the cm relation of cluster elliptical galaxies could be primarily driven by metal - rich stars, whereas the slope of the relation implies systematically older ages for
the effective potential analytic continuation ( epac ) method is proposed for the calculation of the real time quantum correlation function involving the nonlinear operator @xmath5.   the epac method is based on the effective action formalism and an analytic continuation procedure. as a simple example,   we show that the results obtained numerically in the present paper are in good agreement with the results of the centroid molecular dynamics ( cmd ) and the ring polymer molecular dynamic ( rpmd ) methods for the calculated real time correlations of a harmonic oscillator and an asymmetric anharmonic system. to reduce the computational cost required in the epacs calculation, a simplified method of numerical analytic continuation using the maximum entropy method   is proposed.
the derivation of the nuclear forces is probably the most important problem of nuclear physics.   the derivation requires to explain the nuclear interaction without explicitly solving quantum chromodynamics ( qcd ). yet   qcd must enter indirectly in the picture : otherwise we will end up with a phenomenological description instead of a theoretical explanation. here   we present a new formulation of wilsonian renormalization of the effective field theory ( eft ) for the low energy scale @xmath2, which is based on the independence of observables with respect to the cut - off of the uv divergences in the feynman diagrams of the eft and the fundamental theory of strong interactions. by using this formulation   one can describe the dynamics of nuclei and pions without explicit knowledge of the details of the strong interaction of the quarks and gluons inside them.
we introduce a distributed online convex optimization algorithm based on the sgd iterates that efficiently minimizes a sum of unknown convex objective functions over a network of localized learners.   the proposed method is comprehensive, in that any communication strategy, such as the diffusion and consensus strategies, are incorporated into our algorithm in a straightforward manner.    we compare the performance of our algorithm to the state - of - the - art methods @xcite in the literature and present the outstanding performance improvements for various well - known network topologies and benchmark data sets.
molten salts are liquid mixtures of ionic species at high temperatures.   they receive much attention due to their diverse but promising applications that range from metal production to the pyrochemical treatment of nuclear waste. in this work  , we combine state - of - the - art experimental and simulation tools to study a series of lif - yf@xmath2 molten salts of varying compositions. by combining pulsed field gradient nuclear magnetic resonance ( pfg - nmr ) spectroscopy with molecular dynamics ( md ) simulations, we show that the self - diffusion coefficients and electrical conductivity of the electrolytes are in quantitative agreement with experiments. using these results, we discuss the interplay between the microscopic structure of each electrolyte and its dynamic properties.
two - dimensional ( 2d ) turbulence at moderate to low reynolds number is dominated by the existence of coherent structures.   this observation is more or less independent of whether the turbulence maintains an energetically steady state with a fully developed inverse energy cascade or merely coarsens with time as in decaying 2d turbulence. understanding how coherent structures affect the mixing properties of 2d turbulent flows can have profound impact on real world problems, i.e., the effects of mixing in 2d may aid in the understanding of three - dimensional mixing. in this manuscript  , we show that coherent structures influence the statistical properties of the lagrangian dynamics of two - dimensional turbulence in terms of the relative displacement of two trajectories and the stochastic equation for the distance a particle has traveled, on average, over a given time interval. using a combination of numerical and experimental results, we find that the effects are most pronounced in regions around locally hyperbolic points in the velocity field ( saddles ) and within vortices ( centers ) where the particles are advected into thin filaments along the saddle s unstable manifold. when the plane is in a regime dominated by turbulent advection,
relativistic jets of plasmas are thought to explain the intense and variable emission from blazars.   recent observations of tev @xmath6-rays have found remarkably short time variability of the emission of these jets in the 0.310 kev energy band. here   we show that the observed timescale of the variability is only a few minutes, i.e., ~1 s. the origin of the variation is assumed to be the deceleration of the jet by inverse compton scattering off soft photons in the leptonic models or hadronic interaction of relativistically particles and photons with the central black hole mass in the hadronic models. for both models,   the emission spectra of the jets are characterized by two peaks in the @x Math21-@xmath22 representation, where the lower energy peak is located in the optical  x - ray bands and the higher energy peak occurs in the very high energy @x math6-ray bands. during the outburst of pks 2155304 with redshift, the average flux from the jet was more than 10 times typical values observed from the object @xcite. at the same time, the apparent velocity
x - ray emission from agn is thought to be produced in the very central regions of accretion flow, close to the black hole, since this is where most of the gravitational potential energy is dissipated.   observational evidences for this come from results of modeling of spectral features, often showing distortions consistent with those caused by doppler effects and gravitational redshift. in this contribution   we study some of the consequences of the relativistic effects on the variability of x - ray emissions from ag n.. we find that the reprocessed component of the accretion disk shows rather weaker variability than, and uncorrelated with, the variability ( e.g., *??? ) of the primary emission. a number of observations show periodic variability of the energy of a narrow fe k@xmath0 line, suggesting line production in localized regions co - rotating with the keplerian disk. if the two properties  no qpo signal in theprimary emission and a periodic modulation of the fe line  turn out to be universal, this will clearly suggest a non - trivial geometry of the x - rays source.
resonant soft x - ray scattering ( rsxs ) is a new experimental probe for studying complex electronic ordering phenomena involving the cooperative ordering of various electronic degrees of freedom in complex materials.   it is a highly sensitive probe for spacial modulations of spins, charges, and orbitals in complex nanosystems characterized by a very small amount of contributing material, i.e., thin films, nanostructures as well as surfaces and interfaces. to study these phenomena,   the resonant scattering centers are located close to an absorption edge and the virtual transitions from core levels into unoccupied states close to the fermi level depend strongly on the spin, charge and orbital configuration of the resonance scattering centers. here   we review the current state of the art of rsxs and discuss its applications in the field of condensed matter physics.
the theory about the structure of space and time has been discussed from very long time not only among philosophers but also among physicists.   it is very well known the correspondence between newton s disciple s. clark and leibniz about the absolute or relational character ofspace and time. in this article   we will expand some recent relational theories of space, time and space - time to prove that the basic assumption common to all of them is that there exists some fundamental objects out of them which give rise to a consistent model of the physical world.
we show a way to derive a concept hierarchy, involving subsumption of terms, from a hierarchic clustering.   this hierarchy is based on a subsumption relationship between terms, whereas a hierarchical clustering is an embedded set of clusters of the term set. for selected terms,   we use their inter - relationships to build a hierarchy and use this as a central device for summarizing information and supporting navigation. in this article  , we use a different approach : we select the terms of interest in a manual or semi - automated way ; this not only represents expert user judgement but also allows for inclusion of rare or very frequent terms. in one of our three case studies, we used an automated way to select such terms. for each term, we present a hierarchical tree representation of its relationship to other terms, and we show that the hierarchy can be used to represent an ontology. by starting with the former ( binary ) tree representation, we have an extensive theoretical and formal arsenal at our disposal, to represent the main lines of what we need to do, and to help to avoid ad hoc, user parameter - based, " engineering " approaches.
we study the transition rates of a quantum dot ( qd ) and a quantum hall ( qh ) edge state in the strong coupling regime, where the tunneling transitions recharging the qd are stimulated by the nonequilibrium processes in the edge channels.   the cooperation of the two factors, thenonequilibrium excitations in the channels and the backaction of the quantum fluctuations of the fermi sea due to perturbation by an event of tunneling, is manifested in the weak coupling regime by the orthogonality catastrophe, leading to the fermani edge singularity ( fes ) @xcite in the transition rate, and by their asymmetry with respect to the sign of the dissipative component of current.
the properties of hadrons and their masses at finite density and temperature are extremely important to study the phase transition from the hadronic phase to the quark gluon plasma.   recently, baryons have been studied in the context of bethe - salpeter equation ( bse ) for a bound state of the confined constituent diquark and quark interacting via quark exchange. in the present work,   the schwinger - dyson equation ( dse ) is solved numerically at finite temperature @xcite using the lattice - qcd - based schwingersdyson equation. as the condensate disappears smoothly with chiral - symmetry restoration  , so does the nucleon mass@xcite. however, the dressed quark propagator and the variation of the constituent quark mass with temperature are found to be essential to study these two properties.
we analyze the chemical bonds of bare and hydrogenated pd@xmath0 ( @xmath19 ) palladium clusters using quantum chemical calculations.   we use the electronic stress tensor to analyze the bond orders of the pd clusters under full hydrogen saturation. in the first part of this paper, we briefly explain our quantum chemical computation method and describe our analysis method based on the regional density functional theory ( rdft ) and rigged quantum electrodynamics ( rqed ) for @xcite which is used to study the structure and energetics of small palladium cluster pd+@x Math0 ( ~1.2  kcal / mol ). in second part, we define the bond order of the h atoms in pd(h@x math0 ) clusters using our recently proposed bond orders based on local and global energy density - based analysis methods. as a result, we find that there are two types of chemical bonds between pd atoms and hydrogen atoms : the most common one is the h atom with high coordination number and the least common is the bond between h atoms with low coordination number. in both types of bonds,   the bonding nature is different from that of the
the relationship between the canonical huttner - barnett approach and the quantum langevin noise method has attracted much attention in the last years, and several works attempted to demonstrate the validity of this approach from a rigorous hamiltonian perspective.   the aim of this work is to revisit these derivations of the equivalence between the langevine noise and hamitonian method and to show that some unphysical assumptions actually limit the domain of validity of the previous attempts. as a result, the analysis and derivations always included some hypothesis concerning causality and boundary conditions which actually lead to circularity in the deductions and are not applicable to the most general inhomogeneous systems used in nano - optics.
the study of the time - evolution of a non - relativistic charged particle in homogeneous magnetic and electric fields has a long history in physics.   this problem is particularly important in the context of quantum information processing, where it has become possible to reconstruct the wigner function of a coherent state of the center - of - mass of an harmonically bound ion. here  , we review the results obtained by stoler, dodonov and schrdinger in the literature on the evolution of such states in a homogeneous time - dependent electric field using the so - called squeezing operator. for some types of quantum dots, such as inas / gaas quantum dot,   the agreement between the theoretical and experimental results seems to hold for magnetic fields up to 15 t. the generalisation of this relation to the fd hamiltonian in an electric field is also discussed.
quantitative electronic structure theories are essential to the understanding and designing of novel materials and devices.   it is now generally accepted that transport properties of nanoscale devices depend on both the intrinsic electronic structure of the active channel, as well as its interfacial properties with contacts and other scattering centers. in this paper  , we employ a semi - empirical approach to electronic structure that can be adopted for electronic conduction through complex hybrid systems by combining it with the nonequilibrium green s function ( negf ) technique for quantum transport. given a particular atomistic configuration of the contact - channel - contact heterostructure, we seek to determine its transport properties by coupling our electronic structure approach with quantum transport using negf.the results show that the proposed method is particularly useful for simulating the bulk bandstructure of @xcite, which is a multimoded contact consisting of a highly conductive material externally maintained at thermal equilibrium, and a sparsely moded device region that is readily driven away from equilibrium and acts as the active transport channel.
the tiara array @xcite has been designed and built to study direct reactions with radioactive beams using the inverse kinematics of the d(@xmath2n, p)@x Math3n reaction.   the array is used to identify the binary reaction channels and to determine the excitation energies of the populated states by providing position and deposited energy measurements of the light charged target - like residue, which can be emitted over a wide angular range. in this work  , we report the commissioning of the tiara at the ganil laboratory through a study of the single - nucleon transfer reaction @xmath1-ray detection with coincident @xbox 1-ray measurement.
in a recent paper miller - jones et al.   ( 2010 ) present a detail study of an outburst of the x - ray binary ( xrb ) aquila  x-1 ( aql x-1 ), which is a binary system of a k7v star and a neutron star that experiences repeated outbursts. during the canonical hard state of a bh accreting black hole ( bh ) xrb outburst,   a steady optically thick compact jet is expected to be observed. during this transition, however, a major radio flare, brighter than the compact jet, occurs, and optically thin jet ejecta are often observed or inferred to be launched when the " jet line " is crossed. in the present letter   i speculate on an alternative interpretation of the radio and soft x -ray emissions based on magnetic flares from the november 2009 outburst of a qlq  xrb aquila with a compact jet.
the chromosphere is the region above the photosphere where radiative equilibrium breaks down and hydrogen is predominantly neutral ( the latter condition giving the transition to the corona ).   models of the chromosphere have been constructed to explain observations in h@xmath2 and in resonance lines from other abundant elements with opacity high enough to place the formation in these regions even in center - of - disk observations. since some equations are used to restrict the number of free parameters ( not all hydrodynamical variables at all points in space and time are determined empirically ) we call this class of models  semi - empirical models  . typically one assumes hydrostatic equilibrium and charge conservation but no energy equation. in the solar chromosphere  , an additional term is needed in the energy equation  e.g.  energy deposition by acoustic shocks or energy input in connection with magnetic fields ( i.e. currents or reconnection ). in this paper   we discuss the role of the energy model in understanding the nature of the sun's chromosphere.
we study the stability of thin - shell wormholes associated to a string cloud, that is, wormholes which are constructed by cutting and pasting two manifolds to obtain a geodesically complete new manifold @xcite.   we study in detail the amount of exotic matter required for the construction, the traversability and also the stability under perturbations preserving the symmetry of the original configuration. as compared with the schwarzschild case,   the string cloud allows for more freedom in the choice of the configurations to be stable, and also allows to reduce the amountof exotic matter without increasing the pressure. because recently certain attention has been devoted to exotic matter fulfilling the chaplygin gas equation of state, we explicitly impose it on the shell matter to obtain its time evolution beyond a perturbative approach. in appendix   b we discuss a possible extension of the analysis to a related geometry.
nearest neighbor search in very large databases is becoming increasingly important in machine learning, computer vision, pattern recognition, and multimedia retrieval along with many applications in document, image, audio, and video retrievals.   however, it becomes difficult to efficiently store and search huge collections when the dataset size gets larger and larger ( e.g. millions or even billions ). here  , we propose a novel approach to optimize the residual quantization ( rq ) model that is motivated by the noise and shape in the residual space. for each level of rq, we learn one rotation matrix for each residual cluster, and use them to align the residual vectors in each cluster, so as to reduce the global noise and noise increase over each level after the first, and improve overall quantization accordingly.
the large area telescope ( lat ) is a pair - conversion @xmath0-ray telescope, sensitive to photon energies from about 20 mev up to@xmath1 gev.   the lat is an unprecedented monitor of the variable @x Maths x - ray sky, thanks to the large peak effective area, wide field of view ( @x math2  sr ), improved angular resolution and sensitivity.. the fa - gsw service points out basic facts and information about the @x maths 0-ray sky of potential interest for the lat internal science groups, through a day - by - day inspection and review of the all - sky photon count maps collected and of the quicklook science pipeline results ; summaries about the sky surveyed and monitored by _ fermi _  lat, transients, flaring and new sources on six - hour and 1-day time intervals are communicated along with any relevant news to the external multiwavelength astrophysical community using the lat - mw mailing - list ; astronomer s telegrams ( atels ), automatic burst gcns and special Gcns for blazar flares are distributed in addiction to weekly summary reports in the " fmsci
the study of the velocity gradient tensor in fully developed turbulence has led to interesting findings and has contributed to improved understanding of many statistical and geometrical properties of turbulent flows.   the restricted euler approximation of the navier - stokes equations, which assumes an isotropic pressure hessian and neglects viscous effects, leads to an autonomous set of coupled ordinary differential equations for the kinematic viscosity and strain skewness. at moderate reynolds numbers, however, predictions of the stochastic model proposed in ref. @xcite turn out to be unrealistic, mainly because of the weakness of the local closure for the anisotropic part of the pressure he ssian. in this paper, we present a new approach to quantify the precise action of pressure in numerical turbulent flows by studying the probability current associated with pressure in the plane spanned by the two highly relevant invariants of the limited euler ( le ) equation. using singular integral operators, we show that pressure counteracts the development of the singularity implied by the self - stretching term and redistributes the probabilities towards enstrophy production dominated regions. as a consequence, the results are in good agreement with those obtained from
looking at people ( lap ) is a challenging area of research that deals with the problem of automatically recognizing people in images, detecting and describing body parts, inferring their spatial configuration, performing action / gesture recognition from still images or image sequences, often including multi - modal data.   chalearn lap is a non - profit organization that has organized over 10 international challenges in the field of lap, focusing in cutting edge trends in computer vision and pattern recognition, like explainable computer vision, personality analysis, and collaborative competitions ( a.k.a., coopetitions ). in this paper   we briefly review the events organized so far, which are not limited to challenges, but also include, workshops, special issues, and book series. for the first time in 2011  , we introduced the new chalearslap platform, which contains all information and resources from previous and current events, including programs, papers, codes, and data, among others. since then   there have been over 10 challenges organized by chalairn lap, including face analysis, body posture, action / gestures analysis, as well as several special issues and challenges in machine learning ( ciml )
the origin of the high - energy neutrino events detected by the vlv@xmath0 t experiments at high energy is still a matter of debate.   although it is believed that most of the events detected so far have an extraterrestrial origin, theoretical calculations predict the existence of a terrestrial component due to the decays of the unstable hadrons produced by the interactions of charged cosmic rays with the earth s atmosphere. in this paper   we use the same generators adopted in our recent work on the prompt neutrinos, with microscopic interactions described by event generators including up - to - date information from the qcd theory community working at hadron colliders, to produce predictions which can be compared with experimental data recently collected at the largeHadron collider ( lhc ). for the process of hadroproduction of charm quarks from the decay of @xmath3-hadron + @x Math4-had particle, we find that the rate constants of the observed fluxes are close to those predicted by the parton shower algorithms ( ps ) embedded in the shower monte carlo ( smc ) codes, and that the results obtained using the ` powhegbox ` +  `
the ever increasing availability of digital traces of human actions is widely enabling the representation and the analysis of massive amounts of information on human behavior.   the representation of this information in terms of complex networks has led to many research efforts because of the naturally interlinked nature of these new data sources. in this paper  , we present an in - depth analysis of the data we collected at two widely different events that made possible to mine behavioral networks of face - to - face interactions between individuals, in a variety of real - world settings and in a time - resolved fashion : the infectious exhibition at the science gallery in dublin, ireland, and the acm hypertext 2009 conference in turin, italy. by simulating simple spreading processes over the recorded interaction networks,   we show how dynamical processes that can unfold on the close proximity network  such as the propagation of a piece of information or the spreading of an infectious agent  unfold in very different ways in the investigated settings. using aggregated data from the first event, we show that the spread of information along the proximity network is driven by the diffusion of information from one person to the next..we also show that causality plays a role in
the problem of the study and measurement of t - odd distributions in hadron - hadron scattering has recently acquired a certain relevance.   several studies and models have been proposed for the sivers distribution function, including one that shows its possible existence as a leading - twist distribution. here   i present a new model for the nonzero sivers - like asymmetry in collisions between an unpolarized hadron and a transversely polarized proton using phenomenological schemes that are not typical of perturbative quantum chemical dissection ( qcd ), but rather of high - energy nuclear physics. to achieve this,   the model for both the initial " intrinsic " state of a quark in the proton and for initial state interactions between the two hadrons is built in such a way that it is as simple as possible. by using a gaussian form  , all the necessary functions have been chosen in gaussian form and the parameter number has been reduced to the minimum necessary to explore the interesting independent physical situations.the results show that the model is able to reproduce some of the properties of the previously proposed model, but does not reproduce all of them. at the same time, the model also shows
we study lifshits asymptotics for a neumann laplacian on erds  rnyi random graphs in @xcite.   we find that the percolating cluster of bernoulli bond - percolation graphs produces a van hove effect on the integrated density of states of the de novo laplaician, which is independent of the spatial dimension @xmath0 and is dominated by the dirichlet eigenvalues arising from large fully connected cube- or sphere - like clusters at the spectral edge. using a discrete version of the method of enlargement of obstacles, we show that the effect of the finite clusters on the performance of the von hove function is also hidden.
compact groups of galaxies are excellent places to look for interactions and mergers between ( spiral ) galaxies.   the aim of this paper is to determine the extent to which the in compact groups has been affected by the environment, and to compare the mass of the compact groups with that of a reference sample of loose groups ( rlg ), and with a sample of 204 spiral galaxies in the rc2. using a new survey, the parkes all sky survey, we find that the average amount of hydrogen gas in the compact group galaxies is between 40% and 50% of the mass expected by summing the mean mass in comparable field galaxies. however, the mass - to - blue luminosity ratio appears to be very low in comparison to the distribution of galaxy masses in the comparison samples, and there is a dependence of the observed mass on the integrated blue luminosities of the galaxies. when compared to the equivalent loose groups,   several compact groups appear to have a deficiency of co emission, but the rest have co and fir properties similar to isolated galaxies.
the plasma membrane is a complex fluid where lipids and proteins continuously interact and generate signaling platforms in order to communicate with the outside world.   one of the key mechanisms by which membrane molecules search reaction sites is based on lateral diffusion. here   we employ superresolution imaging and single - particle tracking of membrane proteins to elucidate the compartmentalization of the plasma membrane by the cortical actin cytoskeleton. while tracking individual voltage - gated potassium channels as described in our previous studies @xcite, we found that these membrane proteins exhibited anomalous diffusion on the cell surface. using stochastic optical reconstruction microscopy ( storm ) to obtain superresolution images in fixed cells, we find a non - integer fractal dimension for the actin cortex and a broad distribution of compartment sizes as expected for a self - similar structure. from these observations  , we propose that the anticorrelated dynamics are best modeled by obstructed diffusion instead of fractional brownian motion.
accretion disks of blackbody emission from agn have been proposed as a plausible model for the origin of superluminal quasars.   this is supported by the observation that the spectral energy distribution ( sed ) of accretion disks changes with luminosity, which is consistent with the big blue bump ( bbb ) shifting to lower frequency with lowering luminosity. in this article   i show that the scaling law of the sum - of - blackbodies can be used to test the general idea that accretion discs are made from the sum of black body emitting areas.
the magnetic field evolution in plasmas often follows an ideal evolution in which all topological features of the field remain unchanged over time.   this invariance provides a motivation to investigate topological properties of the magnetic field such as magnetic null points, flux surfaces and periodic field lines. here   we review the role of magnetic reconnection in the evolution of astrophysical plasma - like systems, focusing on three - dimensional ( 3d ) magnetic null - points and current sheets. using a localised non - ideal term in ohm s law, we show that reconnection can occur at a hyperbolic ( x - type ) null - point of the electromagnetic field at the intersection of four topologically distinct flux domains, including the solar corona and the earth s magnetosphere. by virtue of the presence of a non - zero electric field component in the direction parallel to the magnetic fields,   the reconnection enables a change in connectivity of the two magnetic field lines and so a change of topology, the process being known as magnetic Reconnection. despite the fact that the energy bound in the previously topologically bound energy is largely frozen - in, we find that some localised regions ( such as current
we study the effect of introducing small pressure perturbations in an otherwise pressure - free gravitational collapse which was to terminate in a black hole final state.   for such a purpose, spherically symmetric models of black hole and naked singularity formation for a general matter field are considered, which undergo a complete gravitational collapse under reasonable physical conditions while satisfying suitable energy conditions. using these models, we show that the final outcome of collapse with pressure is entirely decided by its initial configuration and allowed dynamical collapse solutions of einstein field equations to be formulated. as a result  , we find that the occurrence of naked singularities and black holes as collapse endstates is not limited to the case of the oppenheimer - snyder - datt ( osd ) dust model, which describes the collapse of a spherical cloud of homogeneous dust, but also occurs in a wide variety of other collapse scenarios.. this allows us to examine in general how generic these outcomes are and we study in the initial data space the set of conditions that lead the collapse to a naked singularivity and investigate how ` abundant'these are.
understanding the properties of growing networks with popularity - based construction rules has become an active and fruitful research area. in such models,   newly - introduced nodes preferentially attach to pre - existing nodes of the network that are already " popular ".   this leads to graphs whose structure is quite different from the well - known _ random graph _ in which links are created at random between nodes without regard to their popularity. in this paper  , we apply tools from statistical physics, especially the rate equation approach, to quantify the structure of these growing networks and to elucidate the types of geometrical features that arise in networks with physically - motivated growth rules. using the rate equations, we show that the relative probability of linking from a new node to a previous node ( equivalent to citing an earlier paper ) is strictly proportional to the popularity of the target node. as a result, the number of nodes in the network increases linearly with the degree of the'target'node, leading to a power - law tail for the node degree distribution. by contrast, the age distribution of nodes and the correlations between node degrees tend to be more strongly correlated with the extent of the spread of the link than with the length of the
complex networks have been the focus of the study of dynamical properties of complex systems in nature and society in the last decade.   usually all nodes are assumed to belong to one population or class, and the interactions between two distinct populations have been reported just recently using dynamical network evolution model. in this paper, we propose a model that incorporates a growing network evolution process with nodal attributes which could be thought of as a new class of model. within this framework   we introduce the rate equations that are specific to our model, solve them and obtain analytical expressions that predict the growth dynamics of the degree of individual vertices. for each of the two types of nodes, we derive the degree distribution for each type of node and also derive analytical expressions of the structural, three - point correlations between nodes to study the clustering properties of the networks.
the interpretation of molecular emission line maps is not always unique.   the main source of uncertainty is the absence of the third spatial dimension ( along the line of sight ) in the observational data and the statistical properties of the velocity and density distributions along the lines are difficult to disentangle. here   we show that the slope and normalization of the spectral correlation function ( scf ) of observational maps correlate with the spectral line width. theoretical models of molecular clouds should therefore yield synthetic spectral maps reproducing such correlations, but not all of them can.
quantum tensor networks are a competitive tool to study strongly correlated quantum systems on a lattice.   the density matrix renormalization group ( dmrg ) is one of the most powerful tools for this purpose. in this paper  , we present a new approach to the analysis of fermionic thermal states with a projected entangled pair state ( peps ) ansatz, which is extended to finite temperature by appending each lattice site with an ancilla @xcite. at finite temperature, the peps ansatz is applied to a 2d spinless hubbard model for spinless fermions on a square lattice and its second order suzuki - trotter decomposition is shown to be a good benchmark for the proposed peps tensor network.
in this paper, we consider a system of two intersecting m2 branes and find a class of exact analytic solutions to the eleven dimensional supergravity equations of motion.   the equation of motion for the metric function of one membrane depends on the metric functions of the second membrane in the system. upon dimensional reduction  , we get a three - dimensional system of three d branes in type iia supegravity that preserves four supersymmetries.
abstractwe performed photometry of hd  149026b on two different nights when transits were predicted by sato et al.   ( 2005 ) using a model that we used to determine the system parameters, and the results are discussed in   4. for the first time, we have observed three solar eclipses of this star with a planet of radius @xmath18,@xmath19, and @x math20.. the observations were performed with the 48-inch ( 1.2 m ) telescope of the f.  l.  whipple observatory ( flwo ) at mount hopkins, arizona. during the eclipse,   the star exhibited a time - variable doppler shift that is consistent with a sinusoid of amplitude @x Math8  m  s@xMath9 and period @x maths10  days, which would be produced by the gravitational force from an orbiting planet with a radius of ~1.5  suns. after the second eclipse, the star s flux declined by 0.3% in the manner expected of an eclipse by a planet having a radius < 1.45  kj / cm2
we investigate the transition from the paramagnetic to the spin - glass phase in the small - world random networks with enhanced clustering coefficient @xmath0.   the results are compared with the predictions of the bethe theory, which is a consistent theory of ising magnetism for trees, where closed loops are absent.
the realization of rovibrationally stable dense samples of ultracold diatomic molecules in the lowest rovibrational state that makes them collisionally stable and long - lived remains one of the major goals in the field of atomic and molecular physics.   we combine the approach used in feshbach optimized photoassociation ( fopa ) with stimulated raman adiabatic passage ( stirap ) for reducing the required pulse intensity for the transfer of an entire atomic ensemble into the lowest vibrational level in the molecular ground state. by coupling the initial and a final state to an intermediate excited state, the system stays in a " dark " state, i.e., a coherent superposition of initial and final states, preventing any losses that would otherwise occur from the excited state. during the transfer,   the system is in a low - energy electronic ground state, thus preserving the high phase - space density of the initial atomic gas. using a combination of stirap and fopa, we show that the transfer efficiency of the whole atomic ensemble can be nearly 100% when the laser pulses are applied in a counter - intuitive sequence where a pump pulse is preceeded by a stokes pulse.
mapreduce is a computational paradigm for processing large - scale data sets in a series of rounds executed on conglomerates of commodity servers.   it has been widely adopted by a number of large web companies ( e.g., google, yahoo!, amazon ) and in several other applications such as gpu and multicore processing. while mostly ignoring the details of the underlying parallel infrastructure, existing formalizations of the mapreduce paradigm constrain the computations to abide with some local and aggregate memory limitations. in this paper  , we provide a formal specification of the model, aimed at overcoming some limitations of previous modeling efforts, and then derive interesting tradeoffs between memory constraints and round complexity for the fundamental problem of matrix multiplication and some of its applications.
in a recent paper, one of us ( sla ) analyzed the consequences of introducing gravitation into the framework of trace dynamics pre - quantum mechanics, assuming the metric to be described as usual by a classical field.   the focus of this paper was on deriving an induced effective action describing trace dynamics modifications to gravitation, applying it to the cosmological robertson - walker metric, and beginning an application to the spherically symmetric case. in the present paper, we continue the latter, with a detailed investigation of modifications to spherical symmetric vacuum solutions.
the apparent magnitudes of type ia supernovae ( sne ) have been used to estimate the cosmology - dependent luminosity distance from the cosmic microwave background ( cmb ) and large scale structure ( lss ).   however, there are a number of potential contaminants that can contaminate the measurements.. one of these is the presence of inter- and/or intra - galactic dust which may obscure the light from the sne and make them look fainter. in this paper   we present the well - known multiple lens - plane method applied to the calculation of the magnification of any point- or extended source using the recently discovered sn2003es as a model system. by projecting the mass of each massive object onto a plane at the respective redshift  , we obtain the surface mass density of the galaxies in the @xmath6:th plane. for the nfw and sis halo profiles, we model the lenses as spherically symmetric navarro - frenk - white ( nfw ) or singular isothermal sphere ( sis ) halos and the lensing properties of these are described in sections .
the construction of a desingularization construction for intersecting minimal surfaces in a riemannian three - manifold is carried out by using gluing techniques by singular perturbation methods.   the construction is successful when the initial surfaces are close to a singular limit and the surface is then perturbed to minimality without sacrificing embeddedness. as a prototype,   a series of clifford tori are constructed by gluing a collection of known embedded minimal surfaces together to produce a new embedded surface, called the initial surface, having small but nonvanishing mean curvature introduced in gluing. at the level of the initial interface, this is accomplished through the replacement of a tubular neighborhood of each component curve of the intersection set by a surface which on small scales approximates a minimal surface in euclidean space desedularizing the intersection of two planes along a single line.
we study the shear banding of a two dimensional ( 2d ) foam by injecting air into a background flow to generate extended parallel shear bands.   we find that the size of the shears is proportional to the drag between soap films and the glass plates and the drag of one soap film against another, which is controlled by the ratio of film - glass drag to film - film drag : @xmath0. in contrast to previous experiments which couple frictional dissipation to topological dissipation, our configuration largely eliminates topological rearrangements.
the calice ( _ _ * cal*__orimeter for a_ _ * li*__near _   * c*__ollider _  * e*__xperiment ) collaboration performed tests of new calorimeter technologies for the planned international linear collider ( ilc ).   the analog hadron calorimetry ( ahcal, @xcite ) has been successfully used in all five test - beams. as part of these tests  , we have developed an algorithm for the identification of tracks generated by minimum ionizing particles ( mip ) passing through hadronic showers within the calice experiment. to provide a clean sample of tracks by mip in the environment of a hadronic shower, which includes regions of high local particle density, specific selections criteria for the calor meter cells used by the tracking algorithm are necessary. here   we describe the implementation of the algorithm and its application to the calibration of the detector at the ilc.
the bernevig - hughes - zhang ( bhz ) model is used to study the screening properties and the collective charge excitations of hg(cd)te quantum wells ( qws ) on the basis of random phase approximation ( rpa ).   we present a comprehensive analysis of its polarization function in the static and full dynamic limit, at zero and finite doping. continuously tuning the parameters of the bhz model, we reproduce the limits of pure dirac and pure schrdinger fermions and explore intermediate regimes, in order to understand how analogies and differences emerge. for the static limit, we find a coexistence between a novel interband plasmon and an ordinary (aband ) plasmon.. both plasmons can be rather weakly damped by single - particle excitations and should therefore be observable. at finite doping, under certain conditions specified below that are applicable to hg’s qws,   they merge one into the other in a normal insulating phase, while they remain clearly resolved when the system realizes a topological insulator.
braneworld models have been shown to be extremely rich in phenomena leading to modifications of general relativity ( gr ) at both low and high energies.   the presence of scalar degrees of freedom ( moduli ) is commonly related to the geometry of the entire system and plays a significant role in the phenomenology of extra - dimensions. at low energies, for instance,   braneworld theories are best described by scalar - tensor theories. within this framework, the gravitational couplings become functions of the moduli and standard gr predictions get modified in ways that can be tightly constrained by present astrophysical observations. here   we show that solar - system and binary - pulsar tests can be used to discriminate between different 5d branworld models and to shed light on their extra - dimensional configuration.
the shape of the metallicity distribution function ( mdf ) of the halo of the galaxy, and its shape at the lowest metallicities, has long been limited by small - number statistics.   the results of the large - scale objective prism surveys of very metal - poor stars from the hk survey of beers and colleagues and the he s survey of christlieb and colleagues have now been combined with the data from the sloan digital sky survey to provide a global picture of the shape of this mdf. in particular, the present work shows that the h Halo mdf is characterized by a continuous low - met allicity tail, with a sharp cutoff at  @xmath3, including tails extending up to the solar metallivity on the high side, and to metallicities at least down to =@xmath4, or slightly below, on the low side. for the most recent public data release of the sloa digital skysurvey, the mean diameter of the tail is approximately 1.5  km, and the mean distance from the sun is about 2.5 kpc.
in the very high energy range of cosmic rays ( cr ) experiments one deals with particle interactions at energies significantly in excess of those of present colliders.   this is a severe problem for the description of the backbone of air showers  the hadronic cascade, as the corresponding microscopic theory   perturbative quantum chromodynamics ( pqcd )  is inapplicable for the treatment of general hadronic collisions and the data on secondary particle production in the fragmentation region, being of crucial importance for the development of extensive air showers ( eas ), are rather scarce, especially for scattering on nuclear targets. here   we use phenomenological hadronic monte carlo models, e.g.  dpmjet, qgsjet, sibyll, and epos, to investigate the role of semi - hard parton cascades in the formation of hadronic jets at very high impact parameters. using these models, we show that the observed hadron jets are formed by two main types of processes, the soft and the hard ones, which differ in their contribution to the overall parton density increase : the former are characterized by low parton densities and mainly proceed via non - perturbation soft processes
the magnetic - field strength of coronal loops is a key constraint in the modeling of energetic and eruptive phenomena such as flares and cmes.   however, it has proven challenging to measure through spectroscopic means the magnetic - fields strength within the corona.. here we show that the temperature profile of a coronal loop is not a function that can be freely specified, but instead has a functional form that is a direct consequence of the geometry of the loop. by incorporating curvature and buoyancy into the equation of the mass density  , we find an equilibrium solution where the mass along the loop redistributes itself with a timescale shorter than the cooling time. using this equilibrium model, we construct a nonlinear force - free model of the geometries of the solar corona and test it on a series of high - resolution euv images from the stereo and the atmospheric imaging assembly instruments ( aia and @xcite ). for each set of images,   the model is found to be in equilibrium with the actual magnetic field at the loop s footpoints, and the thermodynamic parameters are in good agreement with the experimental data. when the models are extended to include the shape of the coronal
the random domino automaton ( rda ) is a new slowly driven systems exhibiting avalanche phenomena.   the model is inspired by earthquakes, but in a direct elementary way it is analysed in the context of stochastic cellular automata models. here   we present a description of the model in terms of rebound parameters, which lead to two distinguished special cases : one with exponential and the other with inverse - power distributions. as an unexpected property  , we mention an interesting link between polynomials and integer sequences.
the formation of planets in protoplanetary disks is strongly tied to the existence of dust which makes up about 1% of the total mass of the disk.   the physics of the inner 1 au of protoplan planetary disks strongly depends on the fate of this incoming matter : it might contribute to the local planet formation process and add mass to forming planetary bodies, it might evaporate and be accreted by the star, or it might be recycled in some more complex way. here   we report on experiments that analyze the gravity dependence of the light induced erosion mechanism for particles at the inner edge of a proton - gas interface of a protoplanetic disk. under very general conditions, e.g. by illumination and at low gas pressure ( kw m@xmath2 of intensity and mbar gas pressure ), the surface particles are lifted by the light and then erode to small particles. when this force overcomes gravity and cohesion,   a crater is formed where again temperature gradients develop. if the illuminated spot is limited in size, the developing crater might prevent further release of particle. as a result, the diameter of the crater is reduced and the body is too small to hold its dust by
the ultimate sensitivity of laser interferometric gravitational wave ( gw ) detectors is restricted by the standard quantum limit ( sql )  a specific sensitivity level where the measurement noise of the meter ( photon shot noise ) is equal to its back - action noise ( radiation pressure noise ).   the sensitivity of gw detectors is also limited by classical displacements noises of various nature : seismic and gravity - gradient noise at low frequencies ( below @xmath4 hz ), thermal noise in suspensions, bulk and coatings of the mirrors (@xmath5 hz).in 2004   s. kawamura and y. chen put forward an idea of so called displacement - noise - free interferometer ( dfi ) which is free from displacement noise of test masses as well as from optical laser noise. in this paper   we investigate model originated from a simple toy model @xcite of the gw detector where a single detuned fabry - perot cavity pumped through both of its movable, partially transparent mirrors was analyzed. by properly combining the signals of output ports of the cavity an experimenter can remove the information about the fluctuations of the mirror displacements and laser noise from the data.
the present work builds on results sketched in @xcite and further advances the topic of flat trajectory design in a multi - agent multi - obstacle environment.   first, we provide exact and sub - optimal formulations of the collision avoidance problems between an agent and the obstacles and between any two agents. in both cases   we make use of the geometrical properties of the b - spline functions which allow to bound locally the trajectories obtained through them. in the exact case,   these constraints lead to nonlinear formulation where both the control points and the separation hyperplanes are variables. a simplified ( and hence sub - optimally ) approach is to select the separationhyperplanes from the support hyperplanes of the obstacles therefore reducing the problem to a mixed integer formulation. for the second part of the paper  , we discuss flat trajectory generation and parametrization via b-spline basis functions. using this approach, we show that the geometry of the system can be tuned by selecting the appropriate separation hyperplane for each agent and by choosing the correct separation hyper plane for each set of control points. over extensive simulations, we find that the proposed methods are both accurate and efficient.
the impulsive phase of the august 20, 2002 solar flare is characterised by a very flat photon spectrum at the x - ray burst maximum ( spectral index @xmath4 ).   we show the influence of photons backscattered in the photosphere on the determination of the mean electron flux distribution and compare results obtained by inversion and forward fitting methods. for the h@xmath1 emission,   the spatial correlation of the intensity of the emission from the flare loops with the hard x - rays and the time correlation between them are also studied.
globular star clusters ( gcs ) are spectacular residents of our galaxy s halo and beyond, yet there are long standing mysteries as to how, when, and where they formed.   these mysteries expanded with the recent discoveries of ultra - compact dwarfs ( ucds ), which began to bridge the classical gap between galaxies and star clusters and raised questions of how to differentiate between these two classes of stellar system. while studies of gcs in the milky way ( mw ) are focusing on remarkable clues about their origins from multiple stellar populations, another important window is to examine the extragalactic populations of gcc and ucdfs  to provide additional context, statistics, and opportunities for witnessing formation in action.
we propose a clustering - based iterative algorithm to solve certain optimization problems in machine learning when data size is large and thus it becomes impractical to use out - of - the - box algorithms.   we rely on the principle of data aggregation and then subsequent disaggregations. while it is standard practice to aggregate the data and then calibrate the machine learning algorithm on aggregated data, we embed this into an iterative framework where initial aggregations are gradually disaggregated to the extent that even an optimal solution is obtainable. for three common machine learning problems : least absolute deviation regression ( lad ), support vector machine ( svm ), and semi - supervised support vector machines ( s@xmath0vm )  , we show that our algorithm outperforms the current state - of-the - art algorithms.
the search for the last unobserved particle of the standard model ( sm ), the higgs boson, has been a major goal of high energy physics for many years.   direct searches at the cern lep collider have set a 95% c.l. limit on the mass of @xmath6  gev  @xcite, which is within reach of the fermilab tevatron collider experiments. in this note  , we combine the most recent results of all such searches in  collisions at  which are sensitive to a high mass ( 155 - 200 gev / c@xmath3 ) higgs : the searches for a sm higgens boson decaying to @x Math7 pairs and produced through gluon - gluons fusion, vector boson fusion, or in association with vector bosons in data corresponding to integrated luminosities of 3.0  at cdf and 3.00  at d. these searches are separated into mutually exclusive final states, referred to as " analyses " in this notes.    the analyses are derived from neural - network outputs based on several kinematic variables, including likelihoods constructed from matrix - element
we report on the discovery of the asymmetric iron line in the _ suzaku _ spectrum of the neutron star ( ns ) source cygnus x-2 ( cygx-2 ).   this is the fifth ns source which shows strongly asymmetric red - skewed iron line profile, which is not only common in black hole ( bh ) sources but also in other types of accretion powered x - ray sources. to understand the origin of the red - skewness of these lines it is crucial to correctly identify the physical origin of them because they can be potentially used to study the properties of the accretion close to accreting objects as well as to constrain the fundamental characteristics of compact objects. in this paper   we present a comparative analysis of the relativistic and wind outflow red - skew line formation scenarios in cyg X-2 using monte carlo simulations. by introducing the lt07 montecarlo code into xspec astrophysical data analysis package we find that the wind out flow model is able to reproduce the Red - skewed line profile with the fit quality similar to that shown by the relativist reflection models.. our results indicate that the red shift
we propose a simple model of growing networks whose statistical properties are identical to a more complicated model containing nodes with distinct characteristics.   we calculate the edge distribution of the growing network, the distribution of cluster sizes and the emergence of a giant cluster. in our model   the number of attempted connections made when a new node is added determines the position and type of the phase transition as well as the cluster size distribution.
the equilibrium isotope effect ( eie ) is the ratio of equilibrium constants for two isotopomers.   it is usually computed only approximately :@xcite in particular, effects due to indistinguishability of particles and rotational and vibrational contributions to the eie  are treated separately. at room temperature or above the nuclei can be accurately treated as distinguishable, and the indistinguishesability effects can be almost exactly described by symmetry factors. on the other hand  , the effective coupling between rotations and vibrations, anharmonicity of vibrations, and non - rigidity of rotations can in fact become more important at higher temperatures. here   we study a specific case of eie - the equilibrium ratio of two isoto - pomers. in this case, we use the feynman path integral representation of the partition function to compute the reduced reaction free energy. to include the effects of quantization of nuclear degrees of freedom beyond the harmonic approximation ( ha ) rigorously   our goal is to describe rigorously equilibria at roomtemperature or above.the results show that the error due to the born - oppenheimer approximation is of the order of 1% in most cases
recently, chen _ et al.   reported an experiment that mimicked the quantum - interference behavior seen with an spontaneous parametric downconversion ( spdc ) entanglement source using two independent pseudothermal light beams obtained by passing laser light through a rotating ground - glass diffuser. in this paper  , we present an explanation for the experiments reported in @xcite that relies on semiclassical photodetection theory, i.e., one that only needs classical electromagnetic waves. to do so, we introduce a modified mach - zehnder interferometer with photon - coincidence counting in the low - flux regime that was employed in @xmath7 nm wavelength and 78mhz pulse - repetition frequency and a @x Maths 8fs pulse duration, and use it to derive the singles and coincidence rates as functions of the differential time delay and its polarization - analysis angles.    here we show that our results explain the observations reported in@xcite. furthermore, we show how our theory can be extended to high - flux operation with photocurrent cross - correlation, and we provide some concluding remarks about the implications of our work.
the gammev chameleon afterglow search ( chase ) experiment was designed to produce a population of chameleons in a cryogenic vacuum chamber immersed in a magnetic field @xcite using a high - power pulsed laser and a single photon detector.   the experiment reported seeing an anomalous aftergl glow in their apparatus after having shone a high intensity light source into the bore of a superconducting tevatron dipole magnet, which was then imaged by a photodetector attached to a hamamatsu h7422p-40 photo multiplier tube ( pmt ) that had @xmath3 hz of dark rate of light at a wavelength of 532 nm and a temperature of ~4 kelvin. here   we present all of our data that pertains materially to the characterization of the orange glow signal, including some of our initial observations (  oddruns ), data taken using broadband optical filters (   ), our initial characterization data and science data (  sciruns ), and different vacuum chamber temperatures (   tempruns ). for each of these data, we present a discussion of the potential implications of the results and compare
scale - free networks, termed after the absence of a characteristic typical node connectivity, exhibit many unusual properties as compared to simple lattice models, random graphs, or even small - world ( watts - strogatz @xcite ) networks. in this work, we study a number of random walk properties, including mean - squared displacement, network coverage, and trapping processes on scale - free   networks of varying connectivities.   we find that the network coverage increases linearly with the number of steps taken by the random walker during the walk, while the mean squared displacement decreases linearly when the network is reduced to a certain concentration.    we also show that the trapping processes take place on these networks, and that the results are consistent with the results of previous studies.
the reidemeister torsion is an invariant for a cw - complex and a representation of its fundamental group.   it is known that the fox calculus plays important roles in the study of the non - acyclic cases of the reidemEister torion @xcite. in this paper  , we focus on the non-acyclics by using the relationship between the twisted alexander invariant of a knot and the reemediator torsions for a knot exteriors.we give an explicit expression of thenon - acYclic reidem eidertorsion for the pair of a @xmath3-bridge knot and a @Xmath1-representation of its knot group. moreover, we give a new example of calculation of theNon-aylecyser torsional for a@xmath5 knot.we also show that the critical points of the Non - aylecieser tori are binary dihedral representations of the character variety of a # 3-bridge knots.
we introduce the notion of @xmath0-deformed grading on the enveloping algebra generated by all products in different deformed heisenberg algebras.   this notion generalizes the ordinary grassmann grading and, moreover, by defining a generalized @x Math0-graded bracket, one is able to recover, in each subalgebra, the correct structure for bosonic, fermionic,@xmath1 graded and basic deformed bosonic algebraes.    the extension of grassmann parity affords us to understand ordinary associative superalgebra and their @x math1 graded structure ( the usual framework of supersymmetry ) as limit algebridges when the parameter @x maths20 is used. here  , we also investigate the modified supersymmetric hamiltonian and its deformed supercharges mapping some deformed fermions on deformed Bosons.
quantum optimal control is a key concept in quantum information processing ( qip ) and related technologies.   it is the ability to steer a dynamical system from an initial to a final state with a desired accuracy ; optimal control does so with minimum expenditure of effort and resources. despite its prominence in mathematics and engineering, optimal control was introduced to nmr spectroscopy and to the realm of matter wave dynamics only in the 1980s. since then, the development of optimal control in theory and experiment has gone hand in hand, yielding beautiful results, for example on arbitrary excitation profiles  . however, the way optimal control tools are used in the experiments is rather different from that in theoretical calculations. while the field in calculations is shaped as a function of time, experiments employ spectral shaping, which is often incompatible with experimental pulse shaping capabilities. here  , we review the current state - of - the - art in optimal control research in quantum systems, focusing on quantum nanotechnology.
video streaming applications have become over the past few years the dominant applications in the internet and generate the prevalent part of traffic in today s ip networks.   video files are currently downloaded by customers from large data centers, like google s data centers for youtube files. while this solution can improve performances by reducing delays, the limited capacity of those servers in terms of bandwidth and computing can cause overload. to reduce overload,   one possibility is to use bit rate adaptation. here  , we investigate the effect of bit rate adaptions in a node under saturation with respect to the state of the network on the performance of a video streaming algorithm. using stochastic averaging principles, we show that when the demand can be adapted to the states of thenetwork, the efficiency of the algorithm to downgrade the quality of a given transmission increases.
a commonly used model for the form of the density spectrum in the interstellar medium ( ism ) has been based on a simple kolmogorov power - law model with a large range between " inner" and " outer " scales.   this model has been shown to be consistent with observations of radio scintillation phenomena in the local ism, but substantial observational inconsistencies remain. in this paper, we revisit the investigation of the shape of the electron density spectrum by combining observations from many lines of sight and the scatter among them. using a combination of measurements of the differential faraday rotation angles and large - scale electron density gradients, we find that the spatial power spectrum of the fluctuations in the galactic electron density can be understood as a function of the distribution of the scattering material along the line of sight. for a given profile of the distributed scattering material,   one may compare observations and predictions and so constrain the functional form of both the spatial and the temporal forms of the spectrum.
a data base has been created combining 1100 days of  observations with batse, from jd 2448387 to 2449480 ( to ).   it includes observations of fast variability ( 0.010.488 hz ) as well as flux measurements ( ) and energy spectral fits. in this work   we show that correlations occur between several quantities derived from the energy spectral and power spectral fits, and briefly discuss these results.
muons and muons continue to play a role of utmost importance in precision tests of the standard model of particle physics as well as in the search for new physics beyond it.   they can be produced in comparatively large quantities, they live long enough for many applications and they decay sufficiently fast in a parity violating, self polarization - analyzing weak process which makes them most versatile. here   we provide a brief status update on muon activities at the pulsed proton beam at the synchrotron state - of - the - art research center ( psi ) in tehran, iran.
we studied the coherent magnetic transport properties of a bilayer graphene ( blg ) nanoflake connected to two single - layer zigzag graphene nanoribbon ( zgnr ) electrodes.   the results showed that the application of a magnetic field only on blg as a channel changes the spin configuration and conductivity of the blg zigzagged edge and induces a perfect spin - polarized conductance in the ab- stacked blg structures. moreover, we studied the magnetoresistance effects by changing blg width and length connected between z gnr electrodes and found a gmr up to @xmath0 and suggested that the gmr could be tuned by varying blg diameter and length.
the sunspot number series is the most commonly used index of long - term solar variability ever since the mid-19th century.   it is composed of observations from a large number of different observers who used different instruments and different techniques for observing and recording sunspots. to produce a homogeneous dataset, data from different observers need to be calibrated to each other to produce an index of the quality of a solar observer. in the present paper  , we propose a new method for a direct inter - calibration of data from two or more observers using a simple linear scaling between the different observers ( the so - called @xmath0factors ) based on the assumption that the observational acuity threshold ( i.e., the minimum size of a sunspot group the observer can see considering the used instrumentation, technique and eyesight ) is constant in time. by applying this assumption, we show that the @x Math0factor methodology is formally invalid in the case of sunspot numbers because of several formal assumptions which are usually not discussed, but their violation may lead to incorrect results.
in the previous paper @xcite, we have introduced a self - similar telegraph model of turbulent relative dispersion, and showed that the separation pdf can be close to the prediction of richardson s diffusion equation for slowly separating particle pairs even in the presence of persistent motions. in the present paper  , we check the consistency of the physical picture of the self - like model by carrying out direct numerical simulations ( dns ) of two - dimensional free convection ( 2d - fc ) turbulence instead of three - dimensional navier - stokes ( 3d - ns ) turbulence.   our results show that the effects of coherent structure on turbulent relative dispersions are wiped out by the existence of coherent structures in 2d-fc turbulence, which are approximated by the burgers t - vortex layer. from these results, it is expected that coherence of turbulent field, which must share its origin with fine coherent vortical structures such as worms in 3D - ns turbulence, has a significant role in the anomalous dispersion process.
star formation activity in early - type galaxies is not well understood.   we investigate the relationships between molecular gas and star formation activity using matched - resolution images of the molecular gas distribution, the cm - wave radio continuum and the 24  intensity in a sample of co - rich early - types of elliptical and lenticular galaxies that have unusually large molecular gas contents. for most of the galaxies,   the emission is not intense enough to affect the galaxies morphological classification, as it only amounts to a few percent of the total stellar mass. however, the results are at least qualitatively consistent with the suggestions that present - day star formation may be occurring in substantial numbers of local early -type galaxies.
the identification of high proper motion stars is an important tool to identify neighboring stars.   the simbad database lists some 108 stars with motions above two arcseconds per year, but many more are still to be identified. in this article, we report on two particularly important sources : the wide - field infrared survey explorer ( wise ) and the near - infrared two micron all - survey ( 2mass ). using a strategy based on the fact that nearby hydrogen - burning stars should appear as relatively bright, high signal - to - noise sources in both wise and 2mass, we found that nearly all lspm stars had @xmath5 and@xmath6, and so we applied these color cuts to the sample. at low galactic latitudes,   most of the stars were not matched to the ppmxl catalog ; however, we recovered a number of known stars, such as the 5 " /yr star so 025300.5 + 165258 @xcite  , which move quickly enough that they were not excluded by the sim bad query. for yet lower galactic latitude, @x Math8,
the quantum anomalous hall effect ( qahe ) is a topological state of matter, present in a system with spin - orbit coupling, where symmetry protected dissipationless spin - polarized currents counterpropagate on the sample edges, while the bulk of the sample remains insulating.   we propose a new approach to create materials with non - trivial band topology and large curie temperatures, exploiting the electronic properties of doped mott insulators on a kagome lattice. at @xmath4   the ferromagnetic instability combined with correlation effects leads to surface states of both spin species that traverse the bulk band gap opened by relativistic effects and, the qshe is realized.
the cross sections of the @xmath0eu(@x Math5)@xmath6 tb and @x math0eu (@x maths1,n)@Xmath2 tb reactions have been measured at astrophysically relevant energies using the activation technique.   the results of statistical model calculations strongly deviate from the measured cross section values in the case of reactions involving alpha particles. to check the accuracy of the calculated cross sections, the obtained cross sections are compared with those of the off - line measurement of the corresponding reaction products. for both reactions, the experimental cross sections show a strong dependence on the alpha - nucleus optical potential and this potential is ambiguous at the low energies used in the calculations. since the m1 isomer is by far the most strongly populated state in @xMath2tb, the uncertainty of the half - life of the m 1 isomer substantially influences the obtainedCrossSects, the uncertainties of the cross sections can be reduced to less than 4%.
the normally ordered form of an expression involving ladder or, more generally, field operators is defined as one in which all annihilation operators are moved to the right using the appropriate commutation rules.   such expressions play an important role wherever the fock space representation is used. here   we provide the reader with a general method for constructing normally ordered expressions and explain how to link them to well - known combinatorial problems.we also present analogies between our methods and those of standard field theory, in particular feynman diagrams. finally, we illustrate this approach using examples arising in one mode boson normal ordering.
the quantum fisher information ( qfi ) depends on the estimated parameter and the decay of qfi can be reduced by the squeezed light ( reservoir ) compared with thermal ( vacuum ) reservoir. in this paper, we investigate the effects of reservoir squeezing on the qfi based on the non - perturbation processing @xcite.   we consider a phase estimation scheme which a two - level system with an imposed unknown phase interacts with a squeezed reservoir before the final optimal measurements. to find the influences induced by the reservoir, we derive the non-perturbative master equation by the path integral method lujingjifen. in terms of the master equation  , we obtain the exact analytic expression of Qfi which is related to the precision of parameter estimation. it can be found that the degradation of qFi can be prevented by the squeeze of the reservoir compared with the thermal reservoir if the appropriate squeezing phase matching condition is satisfied.
lmc x-1 ( @xmath1 ergs s@xmath2 ) is one of four extremely luminous x - ray binaries in the large magellanic cloud.   the source has long been known to show a rather soft x - rays with irregular variability by at least a factor of three, and its optical identification was uncertain for many years. using rossi x - Ray timing explorer data from nine observations over a period of nine months, we found quasi - periodic oscillations ( qpo ) with a peak frequency of 0.0751 hz in one of the observations that were consistent with the presence of a black - hole candidate. since the existence of qpo might be related to the spectral state of the system, we undertook a time - series analysis of the data from the proportional counter array ( pca ) during the first half of the observation period. based on the results of this analysis,   we conclude that the qpo came from the hard - tail component of the binary, which was unusually bright at the time in comparison to the thermal component.
the standard model ( sm ) of the zee - model is being extended to incorporate the small masses of the neutrinos suggested by the atmospheric and solar neutrino data. in this paper  , we study the higgs sector of the model to clarify its impact on the experimental search for the scalar ( higgs ) boson at the cern lep and the fermilab tevatron experiments.   we find that the upper and lower bounds for the lightest cp - even higgs boson mass are almost the same as those for the two - higgs - doublet - model ( thdm ), except for the existence of an additional weak - singlet charged higgs field in the zeesh - model. using renormalization group equations ( rge s ), we show that the self - coupling constants of the electroweaks of the two- and three - dimensional higgsbosons are not significantly different from those of the thdm. however, the decay width of the single - loop charge - charged higgss boson can be deviated from the sm prediction by about @xmath8 gev if the integrated luminosity of the collider is large
the galactic center ( gc ) is a massive black hole with a mass of @xmath1 in the near infrared ( nir ).   we observed the gc on 2005 june 18 from 2:40 to 7:15 ut with sinfoni @xcite, an adaptive optics ( ao ) assisted integral field spectrometer mounted at the cassegrain focus of eso - vlt yepun ( ut4 ). for all 44 cubes we extracted a collapsed image ( median in spectral dimension ) of a rectangular region ( 0.25@xmath50.5  ) centered on sgr  a * and containing the three s - stars s2, s13, and s17. using a fit with five gaussians to each of these images, we determined the flux of sgr / s2 by combining nine integrations on a specifically chosen off field ( 712  w, 406  n of s gr  a* ). as a crosscheck we measured the flux difference between a signal region centered on source and a reasonable, symmetric background region ( ~8.59 mjy ; range 8.59 to 9.59mjy ).
a semiempirical shell model mass equation ( ssme ) based on proton magic number z = 126 @xcite is proposed as a substitute inside the interior of major shell regions beyond lead n@xmath1 and with 126 @xmath2 n @x Math2 184.   the results of recent superheavy elements ( she ) experiments are applied to test the agreement of the equation with the data observed in several recent fusion - evaporation she experiments where the produced nuclei are identified by their decay ties to known daughter isotopes. for some of these experiments the observed decay chains do not connect the parent to a known daughter, and several reaction channels are in principle possible.
the origin of the geodynamo as the cause of the earth s magnetism has been in doubt for a long time.   it was only recently that the theory of magnetohydrodynamic dynamos was finally able to explain the observed magnetic moments of planets other than the geomagnetic one and the existence of a scaling law for the precessional origin of all planetary magnetic fields based on the basic equations of the nonlinearly coupled navier - stokes equations and the equation of magnetic induction. since the first detailed measurement of jupiter s magnetic field by the pioneer 10 space probe in 1973 and the discovery of mercurys magnetism by mariner 10 in 1974, many attempts have been made to obtain simple similarity relationships which would fit the observed planetary magnetic moments as function of certain properties of the planets.. however, these similarity relationships have lost appeal because of the difficulties of a rigorous theory of planetary dynamos and the results of laboratory experiments that have shown that they are driven by turbulent flows caused by precession and tides not only in the case of the Earth but also on other planets such as uranus and jupiter. here   we review the current state of the art on the origin of planetary magnetism
we study entanglement in ( 1/2,1 ) mixed - spin systems with nn exchange interactions.   we numerically calculate the negativity of the nn spins and the eigenenergy of the system from which we get the analytical results of the negativities versus nnn exchanging coupling, and the case of finite temperature is also studied.    the results show that the negative eigenvalue of two spins is a good measure of entanglements in the cases of mixed -spin systems.. the internal energy of the model up to eight spins is found to be significantly higher than that of two or three spins. for the system with nnn interaction,   the positive eigenvalues of the four - spin case are obtained from the calculated eigen energies of the two- and three - spin cases, respectively. on the other hand, the values of the zero - state negativity for the systems with only nn interactions are not much different from those of the systems without nnn interactions.
epsilon - near - zero ( enz ) is a property of artificial structures where the permittivity and permeability of the waveguide are close to zero.   it has been shown theoretically that a narrow enz channel would support complete transmission of a signal incident from a larger waveguide @xcite, despite the large geometric mismatch. in this paper   we demonstrate experimentally that the tunneling effect can be dynamically controlled by placing a tuning element within the wavesguide.. this allows for efficient control of the enz transmission, with potential applications in tunable slow - light structures.    we also demonstrate that the introduction of nonlinearity into the system allows the enz resonance to be controlled by the incident wave itself.
the origin of grand - design spirals in barred spiral galaxies is still a matter of debate.   the ballistic closed - orbit theory, which is based on non - self - gravitating hydrodynamic simulations in fixed barred potentials, has been promoted as a bar - driven spiral theory, but several preliminary numerical studies have not reached a consensus about the dynamics of barred spirals. here  , we propose a new theory for the origin of the spiral arms in barred galaxies based on the swing amplification mechanism, which operates through a combination of three aspects, i.e. the shearing flow, epicyclic motions, and the self - gravity of stellar discs. by combining the results of some numerical simulations of barred spiral galaxy - body simulations with experimental observations,   we show that the radial migration of stars in the arm region is strongly dependent on the shear rate of the galactic rotation at every radius ( e.g., from the corotating radius to the distance from the center of the galaxy ), and that the pitch angles are expected to depend on theShear rates of galactic discs. moreover, we find that the velocity of the star - to - star transition between the two arms is
we present a detailed calculation of the  intensities  of the multiphonon raman peaks in graphene.   the raman intensities strongly depend on the electron scattering rate ; moreover, the electron - phonon and electron - electron contributions to this rate can be separated. for the first time  , we show that the multipole raman peak intensities are sensitive to the dynamics of an electron - hole pair in the crystal.    the results of the present calculation are used to extract information about these parameters from the r Raman peak intensity measurements experimentally.
we study the dynamical response of a dense vortex lattice forced into motion by an alternating current induced by an external electromagnetic field.   we assume that the vortices are free from being pinned and thermally excited, which in addition to thermal noise would produce entanglement and bending. using ginzburg - landau ( gl ) theory, we derive a model for the transition between the pinning and unpinned phases of the vortex matter. based on this model,   the system is driven from equilibrium and experiences a relaxation process. at the same time, the magnetic field is nearly homogeneous due to the overlap between vortexices.. the relaxation process is fast in the case of a low - temperature superconductor where impurities are plentiful and vorticles experience a large friction.    in contrast, in the presence of small - scale defects, the relaxation processes are slow.,the results show that the mechanism of the relaxation phenomenon is similar to that of the hall effect in superconductors.
the giant electric dipole resonance ( gdr ) is a powerful tool for studying the effects of nuclear deformation on the excited state of a nucleus.   it is well known that the temperature dependence of the gdr properties is not only due to the fact that the ground - state gdr splits into two components for a nucleus with static deformation, but also to the possibility of spin - induced deformation and orientation fluctuations of the nucleus. in this article, we present a comprehensive compilation of all experimental and statistical data on hot gdr parameters obtained by means of statistical - model calculations over the last few decades. from the collected data, we show that the @xmath0 strength - function model proposed by brink and axel has been extended to deformed nuclei within the framework of the generalized lorentzian model and that the range of gdr widths can be used to calculate the temperature - dependent gdr parameterizations. as a result, we have developed a new set of statistical models for the calculation of hot gDr parameters based on the pauli exclusion principle and the quadrupole - exclusion principle. using these models,   we have found that the average electric - dipole ( @x
we study the effect of mechanical motion on the electric properties of nanoelectromechanical systems ( nems ) operating in the single electron tunneling ( set ) regime.   we focus on experimental realizations based on single molecules, semiconductor beams, and suspended carbon nanotubes. a nems can be represented as a set device coupled to a mechanical ( harmonic ) oscillator that is underdamped by a force acting on the oscillator. at the same time, electrons are moving in the field created by the mechanical vibrations ( for brevity, phonons ) generated by the vibrating oscillator, and the phonons are driven out of equlibrium thus creating the feedback for the electron motion through the nems device. using the classical boltzmann equation, we show that the behavior of the system is dominated by strong mechanical feedback, which is explained by the fact that the transmission of the signal from the resonant oscillator to the set device is mediated by the emission of phonons.
the effects of mixing between bands in the @xmath2 ( sn ) and@xmath1 ( pb ) regions of the nuclear mass table have been studied using a combination of experimental techniques and theoretical calculations.   the experiments carried out over the last few years have provided ample evidence for the presence of many - particle many - hole proton excitations, in particular at and near closed - shell regions, which give rise to shape coexistence and collective band structures. here   we review the experimental evidence for these structures and discuss the effect of mixing among these structures on the properties of the interacting boson model ( ibm ) in the pb region.
inflation is the most widely accepted theory of the early universe, and is typically described via the dynamics of the inflaton, a scalar effective degree of freedom coupled to gravity.   it postulates that the very early universe underwent a period of accelerated expansion, leading to the formation of the large scale structure of the universe ( lss ). given the plethora of models that exist, it is fruitful to consider the inverse problem : given cosmological data, can we deduce the mechanism underlying inflation?   this problem is often referred to as the inflationary inverse problem, and has a long history of antecedents in the literature. here   we present a simple and robust implementation of slow roll reconstruction within modecode, a publicly available solver for the cosmic microwave background radiation ( cmb ) and density perturbations probed by the planck satellite @xcite. using the truncated hamilton - jacobi slow roll hierarchy, we obtain the corresponding inflationary potentials for the wmap5 dataset and the sloan digital sky survey ( sdss ) data release 7 lrg data. adding this potential to the menu of models supported within modECode   yields a simple but
the radial velocity offsets between the emission lines of active galactic nuclei ( agn ) and their host galaxy lines are a well - known feature of quasars, seyfert galaxies, and other visible - light sources.   we have recently used this feature to investigate the possible existence of multiple agn in a galaxy, or an agn that is displaced with respect to the gravitational center of a galaxy. using the nasa extragalactic database ( ned ), we have measured the radial velocity of the narrow - line region ( n ) and broad - line regions ( blr ) of the same emission line from a low - redshift agn, ngc  3341 ( @xmath3 0.027 ), and show that the two sets of emission lines are offset in radial velocity from the systemic velocities of the host galaxy at a distance of 5.1 kpc from the center by about 1.5 km s@xmath0. for the narrow- and wide - line emission lines,   the velocity offsets are more than twice as large as for the broad -line emission lines ; however, they are not so large that they can be considered to be statistically
one of the most important properties of complex systems is community structure.   real - world complex systems are organized in a modular way, with clusters of units sharing similar dynamics or functionality. however, while the clusters are internally cohesive, they can maintain contrasting dynamics. here   we study whether the binary signatures of assets can reproduce the same complex community organization of financial markets, as the weighted information. to this end, we use the daily closing prices of the stocks of three indexes ( s@xmath0p500, ftse100 and nikkei225 ) over the period 2001 - 2011. for each index  , we restrict our sample to the maximal group of stocks that are traded continuously throughout the selected period. using the time series of it s log - returns for each stock in the system, we construct a weighted time series, i.e. both the amplitude and the direction of the fluctuations in the price.    we show that the two types of information are in fact different descriptions of the same system, and are used to construct cross - correlation matrices. in turn, we deploy three popular community - detection algorithms, developed in network theory @xcite, where necessary, for the correct use of
we have constructed an analytical model for the joint formation of ellipticals and quasars in the framework of hierarchical cdm models.   we show that the mass function of dormant supermassive black holes ( bhs ) in the nuclei of nearby galaxies is much larger than expected, and that they are more abundant in the bulges of spiral galaxies than in the cores of elliptical galaxies.. this suggests a connection between quasar activity and the formation of galactic bulges.
the cosmic x  ray background ( xrb ) is a population of faint, absorbed active galactic nuclei ( agn ) with broad emission lines.   the absorbed agn are expected to constitute 80 to 90 percent of the total agn population @xcite. in this paper   we report new observations of a seyfert 1.9 galaxy from the _ beppo_sax  high energy large area survey ( hellas ) at soft energies ( 0.52.0 kev ) and an additional soft component in its optical / near  ir spectra. despite having a broad component to its h@xmath7 emission line, the source appears to be completely dominated by its host galaxy @xaite. it has been proposed to have a counterpart, ( and thus a significant soft x  rays excess ) by @xcites.    the source was detected in two separate observations of markarian 766 using the _ xmm   newton  and  chandra  surveys. both observations were performed in epic mos ( an intermediate resolution x   ray imaging spectrometer, *????)the first observation was performed on 20th may 2000 and had an exposure time
the hamiltonian matrix product states ( mps ) formulation of the dmrg algorithm for calculating ground state properties of strongly correlated systems in condensed matter physics is introduced.   the fidelity of the matrix product wavefunction, or overlap between the wavefunctions obtained from separate calculations, is calculated using the mps formalism, and the results are compared with those of the original formulation of dmrsg ( which uses a mixed effective hilbert space to represent all of the relevant states in the same basis ). while the fidelity is straightforward to calculate, the scaling function for the fidelity depends on the entanglement of the wavefunction @xcite, which for one - dimensional ground - states scales at worst logarithmically with the system size @xmath0. here   we show that this scaling function can be used to calculate the fidelity for periodic boundary conditions, where the number of states kept tends to be the square of that required for open boundary conditions@xcite.
multiple - input multiple - output ( mimo ) systems in wireless communications provide significant improvements in wireless link reliability and the achievable capacity.   however, the detection of symbol vector detection in mimo spatial multiplexing systems is challenging. in this article, we propose an improved multiple feedback successive interference cancellation ( imf - sic ) for signal to interference plus noise ratio ( sinr ) based mimo detection using single - stage detection ( sic)-based detection technique. by checking the shadow region criteria recursively rather than using the conventional sic for searching the best candidate symbol, we achieve a significant reduction in error propagation and thus the minimum bit error rate ( ber ) performance can be improved. also, we employ the log likelihood ratio ( log - lr ) algorithm to improve the detection diversity over the traditional multi - branch sic ( mb-sic ) algorithm.
beryllium ( be ) is a stable isotope of the element beryllium.   it has been known for a long time that it can only be produced by the spallation of heavier nuclei, mostly from carbon, nitrogen, and oxygen @xcite. in the early galaxy,   be is not produced in significant amounts by the primordial nucleosynthesis, because there are no stable elements with mass number 5 or 8 to act as an intermediate step in synthesising @xmath0be@xcite.the current value of the solar meteoritic abundance of be is a(be)(x ) = @x Math7  + 12, i.e. an abundance by number in a scale where the number of hydrogen atoms is 10@xmath8. ]  . however, most 1d local thermodynamic equilibrium model atmosphere analyses of be in the sun tend to find values between 1.10 and 1.15. here   we review the recent advances in the analysis of be abundances in late - type stars.
we report a fitting formula for the two - point correlation function @xmath11 of the virialized dark matter ( dm ) halos in hierarchical clustering models.   the accuracy of the fit is about @x Math12 in @x math13 for a wide range of halo masses, and the bias parameter given by  b(m ) = 1+^2 - 1_c=1+_c ^2(m)-1_c is in good agreement with the analytical prediction.
the jastrow wavefunction  @xcite is a pair - product ansatz for a strongly correlated many - body bosonic ground state.   exactly optimized form of the pair function can be found with the correlated basis functions ( cbf ) theory and the diagrammatic theory@xcite. however, such solutions are often either unknown or unavailable from open sources. in this work  , we revisit this standard procedure. instead of parametrizing the leading - order solution to the pair equation, we parametrze the scattering equation itself.. the trial functions are optimized in the space of solutions of such parametrialized equations.    we find that this results in a robust and straight - forward methodology which provides an excellent description of the ground state when used as part of a diffusion monte carlo.
the twirl operation is a key step in many quantum information processing protocols.   it converts an arbitrary mixed state of a two qubit system into a werner singlet state, an incoherent mixture of parts of a maximally entangled singlet and parts of the maximally mixed state. to achieve this,   the two qubits must undergo a set of bilateral rotations which average any other state of the single qubit subsystem. here   we explore different methods for implementing the twirl, focusing on those which are best suited to ensemble techniques.
the aim of the present paper is to develop a theory describing the long - distance physics of disordered systems through a nonperturbative functional renormalization group ( np - frg ) method and its first focus is the equilibrium behavior of the random - field model.   we show that the effect of rare collective events, such as avalanches and droplets, can be captured by an approach based on the rg flow of the cumulants of the renormalized random field, provided that the full functional dependence of the latter is accounted for. in particular, we stress two important, and distinct, formal properties of the superfield theory :  grassmannian ultralocality " and  superrotational invariance " which are related to the properties of ground - state selection and dimensional reduction. using our np - Frg formalism, we show through our superfield formalism that the supersymmetry of the theory leads to dimensional reduction and we propose a continuation of the np -frg flow equations when spontaneous breaking has taken place.
the large magellanic cloud ( lmc ) has revealed a very complex structure both in the stellar and in the gaseous component.   the old stellar distribution appears to be quite smooth in the outer parts of the disk, with no signs of spiral structures out to a radius of 10 kpc @xcite. within the same radius   there is a strong asymmetric bar at the south - east edge of the galaxy, where the density of the hot gas in the halo of the milky way is 10 times higher than the average in the rest of the lmc. here   we investigate the relationship between the observed asymmetric pattern of star formation and the global geometry of the satellite. using asymptotic giant branch stars, we find that the majority of the star formation events in the last 30 myr are concentrated on the east border of the galactic center, but others are distributed across the entire disk in an irregular and patchy pattern with no apparent relation to the global geometries of the satellites. by comparing the age of the oldest and the youngest star formation systems, we show that the latter are more closely related to the radial motion of the orbital motion vector of the spacecraft than the former
discrete breathers ( db ) are spatially localized solutions which travel along a chain of nonlinearly coupled masses.   they have been observed numerically in the fermi - pasta - ulam ( fpu ) system, but their existence as exact periodic solutions is still an open problem. in this article  , we consider traveling discrete breathers as long - living transient structures which can be described by an effective hamiltonian as presented in  @xcite. here, we distinguish three types of localized structures, characterized by their degree of localization, which could be found in the dynamics of the fpu system : weakly localized standing waves, strong localized breathing, and strongly localized breathing. for each of these types,   we present a general framework to understand the traveling motion of weakly or strongly localized db in fpu chains.
we study the moving boundary problem of the uniform expansion of the highly conducting plasma cylinder in the presence of a constant magnetic field in cylindrical geometry.   we find an exact analytic solution for the problem which can be used in analysing the recent experimental and simulation data obtained with the recently developed @xcite method.    the problem is solved by means of a time - dependent translation of the embedding space from the plane to the electromagnetic field configuration. within this configuration   there is neither an electric field nor a magnetic field. as the plasma expands it both perturbs the external magnetic field and generates an electrical field.. the results are compared with the previously reported exact analytical solutions for the same problem in @xcites.
corot - exo-2a is a late - type g7 star with a short rotation period ( about 4.5 days ) and a remarkable photospheric activity.   its activity is regarded as the manifestation of magnetic fields in the atmosphere, amplified and modulated by a hydromagnetic dynamo. in this paper  , we present some preliminary results about the spot modelling of the light curve of such a star using the maximum entropy spot modelling method of @xcite to obtain a good fit with respect to the solar rotation axis and the planet's longitude. 	 the best fit is obtained with an average standard deviation of @xmath11 in relative units.    the sun is a good proxy for the young sun, probably at an age of approximately 0.5 gyr@xcite.
we have obtained high angular resolution spectra of the source listed in the catalogue of @xcite as.   it is a small, round, dark globule situated in the pipe nebula with no associated iras, msx or spitzer space telescope point sources, and is therefore almost certainly starless. using molecular lines, we have observed expanding motions in hco@xmath0 and cs line profiles across the surface of the globule, but since no protostar has been detected, the source of this expansion is a mystery.. we propose that the expanding motions are caused by oscillatory motions within the outer layers of the globe.
code coverage is a common metric in software and hardware testing that measures the degree to which an implementation has been tested with respect to some criterion.   the aim of testing is to explore as many coverage goals as possible, ideally as quickly as possible. in this paper  , we show that the maximal coverage problem becomes np - complete for graphs with general partitions, and for game graphs in which the tester can choose the next input at a tester node, and the system non - deterministically chooses the next state at a system node. for general game graphs,   we show the complexity of the maximum coverage problem is pspace - complete ; however, there is an algorithm that runs in time linear in the size of the game graph but exponential in the number of coverage goals. again, the re - initializability assumption reduces the complexity of the coverage problem : in case there is a re - initialization strategy of the test set from any system state, the maximal coverage problem for games is co - np-complete. dually, we demonstrate that the problem of whether it is possible to win a safety game while visiting fewer than a specified number of partitions is np - Complete. finally, we consider the
the current - phase relation ( cpr ) in ballistic graphene superconductor - normal metal - supercond conductor ( sns ) josephson junctions is investigated using the self - consistent tight - binding ( tb ) bdg formalism.   the results show that the proximity effect depletion of superconductivity in the s regions and depairing by current are large in short sns junctions, and this leads to a cpr where the critical current is reached for a phase @xmath2 over a large temperature range. for longer junctions with high doping levels,   these effects are not a big issue, and the cpr is still found to be correct.
gravitational waves are gravitational waves which are emitted by the nonspherical oscillation of compact objects.   the observed gravitational wave of the soft x - ray source rx j1856.53754 from the deep chandra letg+hrc - s observations of a neutron star @xcite was used to investigate the quasinormal modes of the star.  in particular, the effects of the density of hadrons and the mass and radius of the blackbody of temperature on the gravitational wave amplitude of the rxj18 56.53753 observation were investigated. as a candidate for a star which is smaller than neutron stars, the possibility of a quark star or a compact star, which is supported by degenerate pressure of quark matter, has been pointed out. because we do not have reliable information about the equilibrium properties of hadronic and quark matters at high densities,   it is not clear what kinds of quarks are realized. here  , we will discuss the possible existence of a self - bound quark Star with a diameter of ~1.5 cm and a mass of ~2.0 cm.
the discovery of more than 40 close binary central stars has been made in the past few years.   this is a major advance in our understanding of the post - ce phase of proton - to - equator ( ce ) nebula dynamics and the ability to predict the formation of new binary systems. here   we review some of the most promising aspects of the new discoveries that have been made since the ogle microlensing survey, including the identification of more wide binary systems and the characterization of the orbital period distribution of these systems.
the stochastic path integral formalism for continuous measurement of quantum systems under weak continuous measurement has been intensively explored in recent years.   the authors recently developed an action principle, based on a path integral representation of probability distributions of quantum trajectories, to investigate the optimal behaviour of the trajectories with arbitrary constraints. in this paper  , we further explore the advantages of having the full joint joint probability distribution of quantum trajectory statistics, including computing statistical averages or expectation values with the ability to condition on definite quantum states at particular times.    we present several examples of the formalism including a qubit system under the influence of measurement alone, measurement with concurrent unitary dynamics, and qubit measurement with feedback control. in these examples,   our approach is similar to that of the martin - siggia - rose formalism, which involves adding conjugate fields through the fourier integral form of delta functionals enforcing diffusive dynamics. in each case,.e., we use multi - dimensional gaussian integrals and diagrammatic expansion theory to compute the joint probability probabilities of the measurement readouts as well as the quantum state trajectories. using a phase portrait analysis, we show that the
the scheme of non - orthogonal multiple access ( noma ), proposed in @xcite by saito et al., is a novel interference management strategy that will manage interference, without increasing the system s overhead, and provide high data rates and reliable transmissions to edge - cell users.   the aim of this paper is to study the power allocation and quality - of - service ( qos ) of noma for the @xmath0-user interference channel in a mimo - noma model, with two different power allocation schemes, a fixed one and a cognitive radio inspired one, using signal alignment and stochastic geometry. as a proof of concept,   we show that the proposed scheme can be applied to the case of the siso broadcast channel ( bc ), which is a heterogeneous network with many small cells and macrocells, and can be achieved with the aid of coordinated multiple point ( comp ) and _ _ alamouti code. based on the results of previous work on interference alignment ( ia ) and blind ia, we propose a new interference management scheme, called topological interference management ( tim ), for the bc, which takes into consideration the position of every
type ii spicules observed in the chromosphere are thought to be responsible for the transfer of mass from the dense chromosphere into the corona and are suggested to play an important role in coronal heating and solar wind acceleration processes.   rapid blue - shifted excursions ( rbes ) are continuation of ca ii 854.2  nm rbes, which tend to be located closer to the network fields @xcite. here   we investigate the relationship between the occurrence of rbes and the changes in the underlying dynamics of photospheric magnetic fields using h@xmath0 - 0.1  nm and magnetic field data obtained with the new solar telescope ( nst, *???   * ; *?????', installed at the big bear solar observatory ( bbso ). on september 8, 2011 and august 14, 2011 the nst acquired quiet sun data near the north pole and in a coronal hole ( ch ) located near the solar equator at heliocentric - cartesian position ( 460 ``45 '' ). in both cases   the acquired data included blue wing images taken with a zeiss lyot filter with a 0
we investigate the excitation of higher - order beams, including optical vortices and soliton clusters, through the inelastic soliton scattering and mutual trapping of initially well - separated fundamental solitons.   the effect resembles a synthesis of'soliton molecules'or'molecules of light'by the interaction of the two types of self - trapped stationary structures of light beams with phase dislocations, i.e., the vortex soliton and the multi - hump optical beam, which can be regarded as bound states of ` atoms'trapped by a common potential induced in a nonlinear medium.    we propose the application of this effect in the context of ` soliton algebra'@xcite regarding the fundamental spatialsolitons as the information carriers, and the transformation of an optical pattern induced by the soliton interaction as all - optical soliton switching.
we study the first - order phase transition between the quark - gluon plasma ( qgp ) phase and the colour superconducting phase in qcd at high baryon number densities ( @xmath1 ).   we find that the formation of droplets of light quarks, antiquarks and gluons is first order in the qgp to colour - superconductor phase transition. as a function of density,   the chiral symmetry is restored inside their droplets ( which they call nucleons ) but is broken outside. here  , we show that this is due to the same physics of activation energy barrier as that of the bose - einstein condensation in a gas of trapped atomic hydrogen.
@xcite recently argued that anomalous flux ratios between gravitationally lensed quasar images are evidence for substructures in lens galaxies.   we present a possible alternative route to these anomalies, and consider the compound lens system such that a lens galaxy lies in a group or cluster. by taking into account the spatial distribution of substructured matter in the group / cluster, we show that the fraction of substructure in the cold dark matter ( cdm ) model is much smaller than that required to explain the observed flux ratios in gravitational lenses.
neutrino is the only probe which can reach the earth from the cosmological distances keeping original direction and pointing back to the source of its origin, meeting thus the basic requirements of _   astronomy.   neutrino astronomy is under way, being still in its infancy. after the first experimental steps at the middle of the 1970th ( the dumand project @xcite ) and detection of the first underwater atmospheric neutrinos at the mid of the 1990th ( baikal experiment @xmathite ) experimental groups and collaborations moved to the next stage : creation of detectors with effective areas of 0.1 km@xmath8 and higher with an ultimate goal to build neutrini telescopes with effective volumes of one cubic kilometer.    this talk reviews the physical goals and experimental status for ultra- and extremely high energy neutrination focusing, first of all, on operating and planned deep underwater / ice cherenkov neutrinal telescopes.
the si(335)-au surface is a representative of new class of systems in which the deposited pb atoms form one - dimensional structures adsorbed on - top of the surface.   the present work presents a structural model of the pb chains on the surface, derived from total energy density functional theory ( dft ) calculations. it features single pb atom per si( 335 ) unit cell placed near the au chain and the p b atoms are bonded to neighboring si and au atoms, forming monoatomic chain located @xmath4 nm above the surface as shown by scanning tunneling microscopy ( stm ) topography data and by the angle - resolved photoemission spectroscopy ( arpes ) spectra taken in the direction parallel to the steps. for the present model,   electrons near the fermi energy are completely decoupled from the substrate due to band gap in electronic spectrum of the substrate, and the chain atoms are bounded to the surface by low energy states which do not contribute to electronic properties of the system. on the other hand, the calculated band structure for the presented model clearly shows one - dimensionality, i.e. a strong dispersion in the directions parallel
the issue of whether increasing the complexity of a network contributes to its dynamical instability has long been debated.   this debate is especially acute in the field of ecology, as it relates to the importance of diversity for the long - term survival of ecosystems. understanding the relation between the network structure and its stability ( with respect to dynamical perturbations ) is crucial because it is related to the robustness of systems as ubiquitous as power grids, financial markets, and even complex societies and civilizations. in this paper   we explore the relationship between the stability of small - world ecological networks and the eigenvalue distribution of the linear stability matrix, which is the leading eigen value of the random stability matrix. using a combination of numerical and theoretical studies, we show that the stability transition from regular to random is not independent of the network topology. however, the nature of this transition changes with the topology, and the stability becomes more stable when the network is introduced into a small- and/or large - world connectivity regime. by comparing the results of our results with those of previous studies on the eigensigner stability theorem, we find that the change in the stability - instability transition occurs at the same critical
we present a formal statement and an assisted proof of a discrete version of the jordan curve theorem ( jct ) for combinatorial map models of space subdivisions.   the hypermap framework is entirely formalized and the proofs are developed interactively and verified by the coq proof assistant @xcite. using an original way to model, build and destruct hypermaps, the present work brings new simple constructive planarity and connectivity criteria that prove the discrete form of jct in a combinatoric framework. it is also a large benchmark for the software specification framework we have been developing in the last fifteen years for map models used in geometric modeling and computer imagery.
wolf - rayet ( wr ) stars are spectacular in appearance, with strong, broad emission lines instead of the narrow absorption lines which are typical of normal stellar populations.   they typically have wind densities an order of magnitude higher than massive o stars, and are the prime candidates for the immediate progenitors of long, soft gamma ray bursts. here   we review the observational properties of classical wr stars in the milky way and beyond, plus physical and chemical properties determined from spectroscopic analysis, plus comparisons with interior evolutionary models, and provides revisions to the excellent abbott & conti ( 1987 ) review.
we present the first progress made towards a complete two - loop calculation of the bhabha scattering process.   we decompose the full one - loop qed matrix element into 12 amplitudes, that is in fact into 24 amplitudes counting the @xmath6- and@xmath7-channel contributions separately. erythroid contributions to the cross section are taken from the corresponding x - ray photon exchange diagrams. at the energy scale foreseen for the next generation of @x Math3 colliders, electroweak corrections can not be ignored. while it is certainly a good approximation to consider small angle bhabhas to be highly dominated by pure qed corrections, this does not apply to the whole phase space. taking the electron mass into account in the genuine qed calculation will open the door to more involved multi - scale electroweak higher order calculations.
we study the phase transition in a generalized version of the one - dimensional symmetric simple exclusion process ( ssep ) with open boundaries. by increasing the nonlocal hopping rate ( or equivalently decreasing the input rate of particles at the boundaries )  , the system undergoes a first order phase transition from a finite density ( fd ) phase into an empty road ( er ) phase with zero density via a clustered state at the transition.   this is quite different from the dynamic instability transitions found in the totally asymmetric simpleclusion process ( tasep ) with non local hopping studied previously  . we claim that two seemingly different transitions in both boundary setups are caused by the same mechanism based on the cluster stability.
quantum key distribution ( qkd ) protocols allow two distant parties, traditionally called alice and bob, to produce a shared random bit string consisting of 0 s and 1 s known only to them, which can be used as a key to encrypt and decrypt messages.   we propose the use of intra - particle entanglement as a useful and easy - to - prepare resource for quantum key distribution, which presents novel elements when state preparation devices, in addition to the channel, are allowed to be insecure. here  , we show that this protocol is secure against certain " side channels " that leak secret data ( such as alice s or bob s settings and outcome information ), whereas the corresponding version of the bennett brassard ( bb84 ) protocol @xcite is not secure. by showing that the security of the prepared state preparation device is not affected by the presence of a side channel, we demonstrate that the method is more secure than the b Bennett brassard protocol.
we present the first application of a new method to determine the luminous and dark mass distribution in the inner regions of massive clusters with giant arcs around a central bcg.   the method combines lensing analysis with stellar kinematical measurements of the bcg, which provide complementary information on the relevant scales ( @xmath10 kpc ), allowing us to disentangle the luminosities and dark components of the total mass distribution. using the keck ii telescope we observe the cluster ms2137 - 23 with a total integration time of 4900s ( 2@xmath191800s + 1300s ) and a redshift of the radial and tangential gravitational arcs of ~1.5  k. the spectroscopic data are used together with archival hst images to constrain the luminescence and dark matter distributions of the cluster. for the latter, we find that the radial arc is a lensed feature, while the tangential arc is not. at the same time, we measure a velocity dispersion profile for the central bcG, which is consistent with the hypothesis that the star - to - planet ratio is lower than expected from the numerical simulations. 	 the results are used to
we study the effects of chiral symmetry breaking in quarkyonic matter, where the number of flavors is very large, and the chemical potentials are confined.   we consider a phenomenological model for confinement, taking the timelike component of the gluon propagator to be @xmath14, and assuming that gluons are insensitive to screening by quarks. using this model, we find that the free energy of exciting a quark at the edge of the fermi sea is dominated by that of the quarks, and that the spontaneous breaking of Chiral symmetry occurs through the pairing of a left handed quark with a right handed anti - quark, and vice versa. if applicable to quantum chromodynamics, our results are of interest to intermediate densities, where both conventional nuclear physics and perturbative treatments fail.
quantum electrodynamics ( qed ) is the only quantum field theory which can be successfully applied to a broad range of effects and energies from microwave radiation to high energies in the gev range and deliver us various accurate predictions for measurable quantities with an uncertainty reaching the ppt level.   the application of qed to the bound state forms a field called _ bound state qed _, which experiences its own difficulties, additionally to qed problems for free particles. here   we review the current state - of - the - art methods for calculating the rydberg constant, the fine structure constant, and the proton charge radius for the bound states of few - nucleon nuclei and for hadronic particles using bound state Qed.
the microcanonical multifragmentation model @xcite is used to investigate fragment average isospin distributions within a phase diagram of the nuclear equation of state ( eos ) during a liquid - gas phase transition.   the results show that the most important ingredients of the phase diagram are the neutron concentration in the gas phase and the proton density in the liquid phase. for low multiplicities,   interesting finite size effects are identified for the distribution of the above distributions. to verify whether the observed signals survive the sequential evaporation stage, effects of the secondary decays are discussed. in order to establish a link with dynamical models predictions, interpretation of the gas and liquid phases with respect to the cluster size   is performed.
we show that spatial entanglement can be detected and quantified for a finite temperature, interacting bose gas of any ( including unknown ) particle number using the single - particle reduced density matrix ( sprdm ).   we apply our scheme to the example of a harmonically trapped, interacting boson pair @xcite, where the sprd m is also used as a quantifier of entangler. for all interaction strengths,   entanlement between pairs of modes rapidly decreases with temperature. while at zero temperature a significant amount of entenlement remains even in the limit of infinite interaction.
we introduce steady - state formulation via scattering state method for electron lattice with fermion baths and comprehensively analyze the model to show that the model is well suited for description of nonequilibrium physics in general.   the theory is applied to the problem of strong - field transport in electronic lattice under a dc electric field, and the results are compared with those of the dynamical mean - field theory ( dmft ) for mott transition and strong - correlation physics in equilibrium.
in the present work we extend our previous studies @xcite,@xcite to the case of the stationary and axially symmetric kerr - de sitter ( kds ) spacetimes, reflecting thus their basic properties incorporating a combined influence of the rotation of source and the cosmic repulsion, recently indicated by wide range of cosmological tests.   we show that the application of the inertial forces concept proves to be very effective and provides simpler and intuitive approach to some relativistic problems, as compared to the standard general relativism methods. in order to demonstrate the effectiveness and simplicity of this approach, we present some examples of the relativist problems, which can be simply investigated by using the inertian forces formalism.
bismuth - doped glasses and optical fibers based on such glasses attract a considerable interest due to a broadband ir luminescence in the range of 1.0  1.7  m employed successfully in fiber lasers and amplifiers.   the origin of the near - ir luminecence in and is still not clear, but recently a belief has been strengthened that subvalent bismuth centers are responsible for it. in this regard, we performed a computer simulation of the structure and absorption spectra of three bism Ruth - related centers possibly occurring in both crystals. basing on the assumptions made in @xcite and on analogy with centers in alkaline halide crystals ( see e.g.@xcite ), we studied the @xmath0 substitutional center as the main form of bismeth embedding in and, the @Xmath1 dimer center, and and complexes formed by the bismothallium subst institutional center and anion vacancy in its first coordination shell. using the generalized gradient approximation of density functional theory with ultra - soft pseudopotentials built with pbe functional @xcites, equilibrium configurations of biclinic centers were found by a complete optimization of the super
thermochemical equilibrium calculations are used to model the chemical behavior of iron, magnesium, and silicon in substellar atmospheres.   the results show that the abundance of each chemical species varies as a function of pressure, temperature, and metallicity, and that the atmospheric chemistry of substellar objects can be superimposed on the abundance diagrams of individual fe - bearing gases to determine their equilibrium atmospheric chemistry.
we investigate the formation of the microscopic, striped ( " secondary " ) patterns emerging in the @xmath0 reaction running in polyvinyl - alcohol ( pva ) hydrogel sheets.   the main characteristics of the parallel and oblique morphologies observed in the experiments have been reproduced by computer simulations based on phase separation described by the cahn - hilliard equation. at high velocities of the cooling front,   irregular morphology ( i m ) emerged. at decreasing front velocity, stripes parallel to the quenching front, called lamellar morphology ( lm ), and stripes perpendicular to the front, termed columnar morphology(cm ) were found. although little attention has been paid to the systematic investigation of the textures when the stripes are oblique to the source front, we will consider these kind of patterns, and refer to them as oblique morphology ( om ).
the phenomenon of mixing - demixing in a degenerate boson - fermion mixture ( dbfm ) of trapped alkali - metal atoms has been investigated using a coupled time - dependent mean - field - hydrodynamic model.   the model is inspired by the success of a similar model in the investigation of fermionic collapse and formation of bright @xcite and dark @xcites solitons in a bose - einstein condensate-@xmath5k degenerate fermi gas ( dfg ) trap. for a weak fermial repulsion at 0   k, we find the formation of a fully mixed state in the central region of the trap which is occupied only by the component with the larger number of fms. for an increase of the trapping frequency from 0 to 1.0  k, the maximum of the probability density of the dfg can be slowly expelled from the central regions of the traps. with further increase of interspecies repulsion up to 2.0 k, however, the total expulsion of the entire dfg could be completely observed. this phenomenon has been termed mixing -Demixing.
the antarctic neutrino telescope amanda and the future km@xmath0 icecube are designed to observe high - energy neutrinos from astrophysical sources.   it has been recognized for a long time that these instruments can detect a supernova ( sn ) neutrine burst because the cherenkov glow of the ice can be identified as time - correlated noise among all phototubes  @xcite. however, the information about the sn signal is far more limited than what can be extracted from a high - statistics observation in super - kamiokande or other low - energy experiments that detect individual events. since galactic sns are so rare, the chances of observing one depend crucially on the long - term stability of the neutriniest observatories. if this is the case, a dual observation in both icecube and another large detector would be especially useful. here   we evaluate icecube s potential as a co - detector from the perspective of the earth matter effects on the sn neutrinino signal from a galactic supernova. while the expected number of detected photons per om was calculated for amanda  , we revisit their estimate for two reasons. first, the sn
the demographics of observed long - period comets have been the starting point of almost all attempts to model the oort cloud. until the last ten or so years  , the vast majority of comets were discovered by systematic eyeball searches, using small telescopes @xcite.   the advent of large format sensitive ccds has now allowed automated surveys to supplant these surveys as the main mechanism for finding new long - periods comets. in this paper,   i attempt to deduce the statistical properties of the long - time comet population from the data of a historical survey of the same region of the sky, using a combination of observational incompleteness and an exhaustive analysis of the historical circumstances in which comets are discovered over a 127 year period ( everhart et al., j. ; r. everhart, m. ; k. ; p. ; n. ; l. ; w. ; d. ; t. ; b. ; c. ; e. ; f. ; g. ; h. ; s. ; v. ; y. ; z. ; x. ; u. ; q. ; a. ; itt. ). based on the results of this analysis,
graph modification problems lie in the intersection of algorithmics, graph theory, and network analysis.   we present four main themes on how the interaction between parameterized algorithmics and heuristics can take place, each time illustrated by some " key " graph modification problems. in section   , we consider a graph - based clustering problem that has been defined only implicitly by means of a greedy heuristic   @xcite. in this case, we show how a natural np - hard parameterized problem ( referred to as highly connected deletion ) can be derived from this, and how this leads to further insight into the corresponding clustering approach  . in sections   : deganon, fast, and pbo, we study parameterized local search  the parameter is the degree of locality  for anonymizing social networks. in both cases, we describe how a closer inspection yields that either the corresponding approach provides optimal solutions in polynomial time or one can derive a logarithmicrometer - size problem kernel with respect to the parameter maximum vertex degree of the underlying graph. in addition, we discuss how one may speed up parameterized algorithms by a clever use of he
the photoproduction of the @xmath5 off protons at low energies from threshold to 500 mev is studied using a fourth order extension of the chiral perturbation theory ( chpt ) of the baryons, heavy - baryon chpt ( hbchpt ).   the effect of the@xmath0 resonance on the electric dipole amplitude at threshold is investigated in the light of the new data for the reaction obtained at the mainz microtron ( mami ) @xcite and the high energy theorems ( let ) obtained by previous theoretical models based on current algebra and the partial conservation of the axial current / = 0.1,  = 5,  = 6,  = 7,  = 8,  = 9,  = 10,  = 11,  = 12,  = 13,  = 14,  = 15,  = 16,  = 17,  = 18,  = 20,  = 21
turbulent aerosols are of interest in a variety of natural and technological systems.   two very important examples are water droplets in turbulent rain clouds and dust grains in turbulent accretion disks around growing stars. in both cases   the suspended particles collide, leading to aggregation or fragmentation of the aerosol particles. in this paper   we discuss the effect of macroscopic motion of a fluid on small particles which have insignificant inertia, so that they follow the flow ( advective motion ). for particles suspended in incompressible flows  , the collision rate falls below the initial transient, but for particles advected in a compressible flow it may increase beyond its initial transient. by solving the fokker - planck equation for the probability density of the separation of particles, we show that the saffman - turner approximation describes an initial transient of the problem only. in the limit where the kubo number approaches zero, however, the equilibrium collision rate is exactly determined.
the expansion method in the harmonic - oscillator basis is used to describe the single - particle wave functions in the deformed mean field potential of the zr isotopic chain where the neutron number goes beyond 82 @xcite.   the expansion method is based on the woods - saxon basis, which is not possible for spherical nuclei at present due to the lack of understanding in strong interaction and numerical difficulties in handling nuclear many - body problems. by using the zero - range @xmath3-force acting on the paired nucleons in the bcs framework, the model is able to take into account the couplings to the continuum well in the non - relativistic mean filed models with the spherical shape.    the new method is applied to the description of the so - called giant halos in the zrs isotopic chains where the proton - skins go beyond magic numbers 40, 50 and 82.
abstractintrinsic absorption is a fundamental component of the agn / host galaxy environment.   it can occur in a wide range of environments, including the interstellar medium, gas streams in galactic halos, or galactic super - winds driven by starburst activity. here   we review the properties of intrinsic absorbers and discuss the implications of partial coverage of the background light source(s ).
we consider the limit of adiabatic pumping of charge and spin through a two - level quantum dot with coulomb interaction.   we use a diagrammatic real - time approach@xcite that allows for arbitrary strengths of the coupling between the quantum dot and its leads. to study the dependence of the pumped charge ( spin ) on the four tunnel - matrix elements in a transparent way  , we introduce an isospin representation of the orbital degree of freedom. by varying the parameters of the mesoscopic system periodically in time,   a finite charge or spin current can be sustained. to emphasize the role of coulomons in the coupling of the quantum dots to the leads, we perform a systematic perturbation expansion to lowest order. using the results of this expansion, we show that the maximum rate of pumping can be found to be 1.5  kcal / mol for the charged charge and 1.0  kj / cm2 for the spin.
we have developed a theoretical description of the dynamics of a lipid bilayer membrane submitted to a local concentration increase of a substance that reacts reversibly and instantaneously with the membrane lipid headgroups.   we focus on the regime of small deformations, and we treat linear membrane dynamics in the spirit of ref.  @xcite. here  , we show that the effect of the evolution of the reagent concentration profile on the membrane dynamics becomes negligible some time after the beginning of the local chemical modification, after what the dynamics corresponds to the response of the membrane to a chemical modification imposed instantaneously. by studying this regime, we find that studying the dynamic response of a biological membrane to its environment enables to extract interesting properties of the response.
time - reversal techniques have numerous applications ranging from medicine to communications and, more recently, imaging in random media @xcite.   the purpose of this paper is to analyze time reversal in the radiative transfer regime using the parabolic wave equation, when the waves interact fully with the random inhomogeneities.we prove mathematically that the refocused signal is self - averaging, which means that it does not depend on the realization of the random medium.the mathematical quantitiy that we analyze is the wigner measure of a pair of oscillatory solutions of the randomly chosen schrdinger equation. in the present setting  , the random potential depends in a markovian way on the variable @xmath1, the main direction of propagation of the waves. in this paper   we use additional regularity of the wigneder measure, available in time - reversal experiments when there is some blurring at the recording array, to show that the whole wigninger distribution, and not only its average, converges weakly, as a schwartz distribution, to the deterministic solution of the transport equation.
we develop a numerical scheme to calculate the spin wave spectrum for a finite but large size model of coupled fermions and spins, in the presence of quenched disorder.   we show that the method accurately reproduces the results for a lattice model of small size obtained from a standard treatment of spin waves via the random phase approximation. at low doping concentrations and high degree of compensation ( which comes from charged centers ) seen in diluted magnetic semiconductors ( dms ), short length - scale density fluctuations could lead to inhomogeneities in the local charge densities at different mn sites, which in turn leads to ( microscopically ) inhomogeneous magnetizations of the magnetic ions in the ordered phase. such inhomogeneity would be expected to alter the nature of the collective magnetic excitations ( spin waves ) of the magnetically ordered system, which then would affect charge transport through the magnetic excitation processes which give rise to spin - flip scattering.
the frequency shift and the damping rate of the sloshing mode in an anharmonic trap are described theoretically.   we compare our results with the experimental data available from the innsbruck group @xcite and with the numerical results by wu and zhang ( wu et al., 2015 ) for the frequency and damping rates of the radial quadrupole mode and the bending mode in trapped fermi gases using the phase - space moments method. as a consequence of the anharmonicity of the trap,   the frequency of the Sloshing Mode is shifted, and the shift depends on the system parameters such as the scattering length characterizing the interaction strength, the number of atoms in the cloud, the temperature of the atom cloud, etc. in the present paper, we also discuss in detail the mechanism of the damped mode.
we consider the exact static superposition of a schwarzschild black hole and a thin disk in presence of a magnetic field.   the method used to include the magnetic field is the well - known complex potential formalism proposed by ernst @xcite, using as seed solutions simple vacuum spacetimes representing the field of a thin disks and a black hole. for models of thin disks with purely azimuthal pressure and current we derive models of two pressureless ( dust ) streams of counterrotating charged particles moving along electrogeodesic. using the rayleigh criterion we derivate for circular orbits the stability conditions of the particles of both streams. also a simple model of active galactic nuclei is studied based on the superpositions of a blackhole, a kuzmin - chazy - curzon disk and two rods representing jets in the presence of magnetized weyl fields.
the critical casimir effect is the thermodynamic analogue of the casimir effects originating from the confinement of vacuum fluctuations in a binary liquid mixture.   it is due to the presence of long - ranged thermal fluctuations in the confined fluid close to its critical point at @xmath0. for two surfaces opposing each other, depending on the mutual combinations of boundary conditions ( bcs ) critical cas Vladimir forces are either attractive or repulsive. here  , we study the quantum - electrodynamic casimir force for geometrically structured confinements which exhibit a periodic pattern with period consisting of rectangular crenellated walls and merlons of width and depth. by monitoring the thickness of wetting films upon approaching a critical end point @xcite, we show that the critical casmiraclavas induced by the geometrical pattern can be used to trap particles reversibly along the lateral direction in a designated way @xcites.    the results are compared with those obtained by measuring the critical adsorption profiles of colloidal particles suspended in a mixed binary liquid solution containing aqueous solutions of water and a binary liquids.
we propose an individual - based stochastic competition model for competition between two species, which is essentially a modification of a deterministic lotka - volterra type model.   we introduce, as the individual characteristic, a rudimentary " genotype ", which determines the individual s adaptation to the environment, as well as its interaction with the other species. in order to reproduce the most common biological observations, namely competitive exclusion and coexistence by character displacement, we convert equations  into probabilistic rules for individual reproduction / death. using these rules, we show that coexistence can be possible for very similar species competing for the same resources, without niche partition. given some specific conditions,   the model can also reproduce the less commonly observed coexist by _ converging _ evolution.
the atmospheric helium abundances of subdwarf b stars ( sdbs ) are poorly understood.   we present the results of a quantitative spectral analysis of a sample of 46 sdb stars from high resolution spectra using the spas routine developed by h. hirsch and the feros spectrograph at the eso / mpg 2.2 m telescope in la silla, Spain. for the majority of the stars,   the atmosphere is dominated by the light isotope @xmath0he, which is enriched with respect to the usually more abundant@xmath6he. among the stars with subsolar helium abundance, two distinct helium sequences   are found : the upper sequence stars lie near the extreme horizontal branch ( ehb ) band in the @x Math5-plane, whereas the lower - sequence stars have a much more dispersed area on the continuum between the upper and lower planes.
the arpes ( angle - resolved photoemission spectroscopy ) intensity measured in the cuprates @xmath4 ( bi2212, bisco ) is strongly dependent on the energy and polarization of the incident light.   we have used the one - step methodology @xcite to study the contributions of the excitation of states in the vicinity of the fermi energy around the @x Math1 symmetry point to the arpes spectrum of bisco. using the three - step approach, we show that the response of the antibonding and bonding combinations of states from the@xmath0 bilayers is found to display a strong energy and polarizing dependence. for the initial and final states,   the polarization dependencies are more prominent when the intrinsic cross - section for exciting certain states of the pristine lattice is large ; in contrast, the effects of deviations from the tetragonal symmetry of the system via various distortions and modulations will become more prominent.
a theory of quantum gravity is necessary to describe the quantum behavior of space and time and to understand what happens in strong gravitational fields, when curvature reaches the planckian regime.   finding this missing theory of Quantum Gravity is one of the big open problems in theoretical physics today, and it concerns the most fundamental ingredients of our existing theories : space - time and its curvature. in this contribution to the ahep special issue on'experimental tests of quantumgravity and exotic quantum field theory effects'  we will discuss a possible phenomenological consequence of quantumravity that has so far received very little attention  the existence of space -Time defects. in many approaches to quantum gravity  such as causal sets, spinfoams, causal dynamical triangulation, loop quantum gravity, and emergent and induced gravity scenarios based on condensed matter analogies  , we expect that the apparently smooth background geometry that we see only emerges as an approximation at low energies and large distances. in order to test or at least constrain the presence of these properties, we propose to look for imperfections in this discreteness. if such imperfections exist, they will cause deviations from general relativity, since general relativity rests on the assumption
the @xmath0 model in two spacetime dimensions with twisted boundary conditions is studied as a toy model of the yang - mills theory in four dimensions.   it is found that the compactified theory is in the weak - coupling regime ( @x math6 ) in qcd(adj. ) on@xmath7 and is composed of fractional instantons and anti - instantons with vanishing topological charge ( instanton number ) and zero magnetic charge. for compactified space with small @x Math5,   the perturbative analysis is reliable and shows that the wilson holonomy stabilizes the @x maths2 twisted boundary condition. in this case  , one can demonstrate the condensation of classical field configurations composed of fractions of instanton and anti-instantons with magnetic charge, which are called magnetic bions. to obtain the re - summation of such divergent series, the borel transformation is used.. the results show that the reparameterization of the Borel transform exhibits singularities on the positive real axis producing an imaginary ambiguities in the nonperturbative sectors, which is called resurgent expansion @xcite. by taking account of the
the virgo cluster is the nearest rich, young cluster in the universe.   it is also the most distantly related of the three - dimensional filamentary structures that tully ( 1982, hereafter t82 ) previously identified around this cluster. here  , we use a statistically robust dataset of all galaxies with available radial velocities less than 6000  km  s@xmath5 to investigate the large - scale galaxy distribution around the virgo clusters.. we find that the distributions of filaments and sheets in the vicinity of the virgos cluster are similar to those of t82, but are more likely to be dominated by over - densities of prolate and oblate over- and under - density rather than narrow filaments. using hubble diagrams, we show that the observed over - density of these structures is consistent with the hierarchical structure formation scenario, with z  @xmath2  0 filaments being the current end point of large -scale structure evolution. for the first time, we search for previously unknown structures that may be associated with the vir go cluster.    we find two new structures, namely, a protoplanet and a supergalactic sheet, which are separated
a new method for the calculation of loop amplitudes for complex processes at the tev energy frontier is presented.   the method is based on the analysis of the master integrals of a series of multi - loop processes with multiple external legs and many kinematic scales. in order to compute the amplitudes of these processes,   one reduces the number of terms to a few master integrations and computes the latter analytically. using the classical method of passarino and veltman, we find that the coefficients of the @xmath1-expansion in terms of known analytic functions can be easily obtained by means of the method of sector decomposition, which simplifies recursively the singularities of feynman parameterizations and allows a straightforward expansion in @x math1. the methods are then applied to the calculations of cross - sections for processes with higher final - state multiplicity, number of loops, and kinematics ( e.g., two - loops or three - loops).the results show that the proposed method is robust to the influence of the tensor structure of the process and can be used to compute amplitudes with up to four internal legs and up to three k
the taurus tunable filter ( ttf ) instruments @xcite@xcite at the anglo - australian observatory ( aat ) and william herschel telescopes ( wht ) have seen use in many key areas of astrophysics.   this paper describes the characteristics of these instruments and the future role they could play at the vlt.
we present solutions for the anisotropic gravastar model proposed by cattoen, faber and visser ( cfv ) @xcite.   the model is a spherically symmetric model of an asymptotical schwarzschild metric sphere in which a repulsive de sitter core is formed by gravitational collapse of a massive star. in the first part of this paper   we describe the evolution of the model and one of the solutions ( model 1 ) which reproduces the cfv sketch of the theoretical model of the gravityastar.. stability of this solution with respect to axial perturbations is calculated.    finally, we discuss the possible extensions of the proposed model.
the multiplicity of red giant period - luminosity ( p  l ) relations has been a major discovery on the road to interpreting complex light variations of these stars.   we report on a combined analysis of macho observations of eclipsing binaries and red giants in the large magellanic cloud, which shed new light on these stars and on the long secondary periods ( lsps ) phenomenon. using two sets of publicly available almost eight - year long macho light curves, we re - determined the periods of all 6833 eclipsing binary stars and 2868 red giant variables from the macho project by re - determining their periods using the phase dispersion minimization method @xcite and the string length method @xmath2. for the latter, we also examined the color variations to identify and exclude pulsating stars with sinusoidal light curves. after this analysis, we identified 3031 stars as genuine eclipsing or ellipsoidal variables and classified the binary sample using fourier decomposition of their phase diagrams. among them, we found that only stars with " w uma - like " light curves composed the sequence of the red giant binaries, while detached and semi - detached systems are spread everywhere in the p
we present a study of closed and open quantum system evolution that goes beyond one - body system hamiltonians by including interaction terms between the system particles.   we describe an efficient method for the preparation of entangled states using the level crossing structure of the system s energy eigenstates. in the case of a bipartite system,   the process of entanglement creation is studied through adiabatic evolution and its degradation is shown to be dependent on the form of system - environment coupling. as a separate but related topic, we show that a method of error protection using entangled states emerges from a variation of the above procedure. here  , we devise a scheme to protect the information encoded in a single qubit from bitflip and phaseflip errors using entangled state - mediated error protection.
we use qcd sum rules to determine which of the 5 scalar - isoscalar mesons currently listed in the particle data group tables  @xcite is the lightest @xmath12 meson in the isospin-1 channel.   the results are compared with those of previous studies using laplace sum rules, and it is concluded that the @x Math17 state is the most likely one.
low frequency quasi - periodic oscillations ( lfqpos ) are common features observed in x - rays emitted from stellar mass black holes.   since a black hole does not have hard surface, the emission of oscillating hard x - ray is very puzzling. here  , we propose a new model to explain the origin of lf qpos in the context of super massive black holes using the two component advective flow solution ( tcaf ) based on the magneto - acoustic resonance oscillation of the transition layer surrounding the compton cloud and the cooling time scale due to comptonization in cenbol roughly matches with the infall - time scale in the post - shock region of an advection flow which also has much lower angular momentum. by using the tcaf,   we show that the low frequency qpos can be explained by the existence of standing shocks in the vicinity of the horizon where infalling energy may be dissipated and jets / outflows may be formed.    the oscillations of the shock oscillation model are caused by the agreement of bremsstrahlung type cooling and infall time scales in the area of the equilibrium between the two components of the advections.
the transport of energy or heat has been intensively studied since fourier introduced his famous law of heat conduction in 1807.   surprisingly, still 200 years later, some fundamental problems remain unsolved, e.g., the classification of the transport properties of a system into normal diffusive or ballistic behavior. in the classical domain, it seems to be largely accepted that normal energy transport, i.e., spatial diffusion instead of ballistic transport or localization, requires the chaotic dynamics of a nonintegrable system @xcite. however, contrary to our everyday experience, the appearance of diffusive behavior according to fourier s famous law is difficult to obtain from the direction of any underlying microscopic theory. in this paper  , we consider several model systems according to their transport properties and compare results from the bath coupling method with those from the kubo formula. for chainlike systems in sect. , we show that the quantum master equation ( qme ) can be used to integrate the monte carlo wave - function technique@xcite which is used to investigate the transport behavior of the system. for two different types of spin models, we find that the qme is able to
the discovery of very bright quasars at redshift @xmath11 in the sloan digital sky survey suggests that some supermassive stars ( smbhs ) as massive as a few@xmath12 already existed when the universe was less than 1 gyr old.   the presence of these so  called " seed bhs " presents a puzzle, since they are expected to form at redshifts as high as @x Math14, and leave behind remnant bhs with similar masses. here  , we propose a new model for the origin of these smbh, which involves rapid gas accretion and collapse in halos of metal  free gas in the core of lower - mass minihalos, or by forming a single smbh in the intermediate state of a very massive star, a dense stellar cluster, or a quasistar. using ultra  high resolution simulations, we show that the gas in such halos can be photo  dissociated efficiently, and cools to temperatures of @x math21 k. however, the gas could fragment on smaller scales if it is exposed to an intense uv flux, i.e., to a critical flux that increases linearly with
the hierarchical reference theory of fluids ( hrt ) was formulated more than 25 years ago as an attempt to reconcile the renormalization group ( rg ) approach, an extremely general and successful theory of second order phase transitions formulated in field - theoretical language, and the microscopic point of view adopted within liquid state theory.   the main goal of hrt was to develop a unified theory able to reproduce the universal properties at the critical point, as obtained by rg techniques, together with the non universal features of realistic models of fluids, present both in the critical region ( e.g. critical density and temperature, short range correlations ) as well as far from the critical points. since the early nineties, sophisticated functional, non perturbative rg techniques ( nprg ) were devised within field theory, leading to a boost of applications to many and diverse physical situations : from particle physics, to quantum many body theory, to classical statistical mechanics, to fluid mechanics. here   we summarize the advances in hrt which took place in the last decade, providing a guidance to the most significant recent applications.
we propose a new four parameters distribution, referred to as the blfr distribution, which contains as special sub - models : the beta exponential ( be ), beta rayleigh ( br ), generalized linear failure rates ( glfr ) and linear failure rate ( lfr ) distributions, among others.   the main reasons for introducing blfr distributed are : ( i ) the additional parameters introduced by the beta generalization is sought as a means to furnish a more flexible distribution. ( ii ) some modeling phenomenon with non - monotone failure rates such as the bathtub - shaped and unimodal failure rates, which are common in reliability and biological studies, take a reasonable parametric fit with this distribution.  in this article  , we investigate some properties of the distribution including the limit behavior and shapes of the pdf and hazard rate function.  we provide a general expansion for the moments of the blfrs distribution. we discuss maximum likelihood estimation and calculate the elements of the observed information matrix.  we perform a simulation study and find out the best fit of the obtained results.  we find that the proposed distribution shows better fitting, more flexible in shape and easier
we study the model of quantum universe proposed in the inflationary model @xcite.   it does not meet with the problems mentioned above and comes to the friedmann - robertson - walker model with positive spatial curvature within the limits of large quantum numbers. by means of modification of the action functional   we find the solutions of obtained classical field equations. for the quantum theory for a system of gravitational and matter fields we formulate the equation which is an analog of the schrdinger equation and turns into the wheeler - dewitt one for the minisuperspace model in special case. in this way   the proper dimension of the nonhomogeneities of matter density and the amplitude of the fluctuations of the cosmic background radiation temperature in highly exited state of the universe can be calculated. as a result  , we propose a new possible quantum mechanism of the observed properties of our universe.
ngc 1232 is a nearly face  on, gas  rich, late  type spiral galaxy.   it is a prime candidate for studies of the radial trends of the neutral gas velocity dispersion as a function of radius. in this paper  , we report the results of high - resolution hi synthesis imaging observations of ngc 1231 using the very large array ( vla ) with the dnc configuration of the Very large array and the 2ad correlator. during the measurements,   the observed neutral gas distribution and kinematics are compared with those of previously reported observations of the outer gas disk of other faces  on spiral galaxies. despite adequate spectral resolution, the observations suffer from significant rotational broadening, in part due to a severe warp in the gas disk. however, these observations do provide additional insight on radial trends that have not been previously reported.
we consider the use of cooperative beamforming ( cb ) mixed with cooperative jamming ( cj ) to achieve secrecy transmission from a transmitter ( tx ) to a legitimate receiver ( rx ) with the aid of a set of single - antenna wireless energy harvesting ( weh)-enabled amplify - and - forward ( af)-operated relays in the presence of multiple single- and multi - antenna eavesdroppers.   we optimize the cb of the relays and the cj covariance matrix by jointly optimizing the power splitting ( ps ) ratios of the relay helpers using a joint optimization algorithm that exploits the benefits of weh - enabled af - operated relays, subject to the eh power constraints of individual relays. for the case of uncoordinated cj,   the optimal ps ratios are found to be as follows : 1.5  :  0.1 for the ps ratio for the transmit node and 1.0  : _ 0.2 for the destination node, while the optimal cb - cj ratio is 1.8  :_ 0.3 for the source node and 2.4  : 0.6 for the recipient node.    our results show that
radio tomographic imaging ( rti ) systems can be used to localize and track people in indoor areas using the changes in received signal strength ( rss ) measurements made by a network of multiple static wireless devices.   an effect we have observed over many rti deployments is that the performance of an rti system can be dramatically altered ( improved or degraded ) by small ( sub - wavelength ) position changes of the deployed rf sensors. while " guess - and - retest " is possible and will ultimately reduce localization error, it is extraordinarily time - consuming and as such is unsuitable for a real - world deployment of a commercial rti System. in this paper  , we introduce an rtiservice system composed of servo - nodes, which are equipped with a servo motor and are capable of performing small - scale, on the order of a wavelength, adjustments of the position of the autonomously rotating rf sensor. each servo-n node is equipped with its own servo motors and is capable of rotating to optimize its own position. through three deployments, we show that this procedure, which we refer to as _ calibration _, reduces localization error by 30% to 37%.
capella ( @xmath2  aur ; g1iii / g8iii ) is one of the most coronally active stars in the universe, and has been a common calibration target for x - ray and euv instruments.   it is a remarkably stable source, with no discernible flaring activity. here   we analyze recent observations of capella made with the /  (   ) high - sensitivity high - energy telescopes, and find that variability indeed can be detected at short timescales ( < 1  ks ). this variability can occur due to many causes, ranging from cyclical dynamo variations, to rotational modulation, to active region evolution, to flaring, to heating, and even to flares.
the external shock model predicts that the afterglows of the grb engine are characterized by a power - law decay in time, with the possible presence of breaks connecting branches of different slope.   the temporal properties of the flares, their intensity, and their spectra suggest an origin that is unrelated to the external shock, at least for a fraction of the bumps. in this paper   we compute external shock timescales for two different scenarios : prompt emission and late episodes of " prompt emission".we show that at least a large fraction of x - ray flares are due to a long lasting activity of the inner engine, rather than to external shock activity or to the emission of slow shells immediately after the prompt emission ends. comparing our results to the _ swift   data reveals that the timing of the flare is much longer in the case of prompt emission than in the cases of Prompt emission. however, the latter is not always the case, as the flare can be produced by a sudden brightening of the externalshock.. the latter may be due to the formation of a tail of slower material from the internal dissipation of the fast ejecta during prompt emission, which is ejected immediately after it ends.
the hadronic cross section is a measure of the number of massless quarks and gluons in the final state.   it is known to factorize into parton distribution functions and the partonic cross section, which are non - perturbative objects and have to be determined experimentally. here   we show that the cross section can be predicted by using phase space integrations of the two - loop matrix element of the virtual contribution and the one - loop amplitude of the real contribution. for each measurement,   the cross sections are reduced to their corresponding contributions at next - to - leading order ( nlo ) and beyond this order. when these contributions are extended beyond nlo, they are further decomposed into the double - real contribution, which contains two additional massless partons in its final state that can become unresolved and lead to poles in the phase space of the second parton of the first parton. as a result, the predictions are consistent with experimental data.
the mass - loss rate of red giants and red supergiants ( rsgs ) in the lundmark - melotte dwarf galaxy ( lmc ) is strongly dependent on the metallicity of the dust grains around them.   this dependence is explained by the strong pulsation of the cool photospheres of these stars, which acts as a piston to increase the scaleheight of the molecular atmosphere, facilitating the condensation of grains of circumstellar dust. here   we review the current state of knowledge about the methods that are used to measure the wind speed of the wind from infrared spectroscopic observations of such stars using the spitzer space telescope.
we present the equation of state for the mixed phase in the cores of hybrid stars taking into account the charge screening effect.   we investigate the inner structures of these stars using density functional theory and the tolman  oppenheimer  volkoff equation. with respect to rotation, we find that the inner structure of the core of a hybrid star is strongly affected by the presence of quark matter.
we study a special atom - cavity hybrid system in which the cavity field couples the internal states of atoms and affects the collective properties of the ensemble.   we show that the cavity - induced inter - band couplings play a crucial role in inducing the topological phase transition between the conventional and the exotic topological superradiant ( tsr ) state, and that the back action of the cavity photons on the atoms leads to a self organisation of the bose - einstein condensate. as a result, local order parameters coexist with global topological invariants in the tsr state.
the electromagnetic interaction between charged particles produced in the collision and the nuclear remnant that does not participate directly in the reaction ( the  spectator system  ) is of particular interest because it provides independent information on the space time - evolution of the reaction.   this paper presents a proposal for the use of the nica ( nuclotron based ion collider facility ) research programme at the cern sps to study the spectator - induced electromagnetic interaction in nuclear collisions. as a first step  , we discuss the principal features of the spectator effect, with particular emphasis on its importance as a new source of information about the mechanism of the nuclear reaction. in section   , we define the possible future contribution of nica to the field of heavy ion research. in sections   secfour and secfive, we briefly address the subject of competition from other experiments. in finally, we present our conclusions.
we derive an upper bound on the size of a lattice scheme, which will be called lattice singleton bound ( lsb ) for the remainder of the paper.   we derive a new upper bound for non - constant dimension codes by applying the lsb to the projective lattice. in particular, we consider the gilbert - varshamov type bound, which we will term as ` etzion vardy- gilbertshichangov bound'( ev - gvb ), and derive a _   new upperbound on the code size using the same approach.
@xcite superlattices with several regions of negative differential velocity ( ndv ) have been studied experimentally and theoretically.   the properties of these traveling gunn - domains are studied extensively theoretically and experimentally leading to several proposals for applications. in this paper   we show that a third type of oscillations can be observed in lightly and moderately doped superlattenices ( sl ) in field regions where tunneling into higher subbands takes place, which may be controlled by varying the doping in the quantum wells. under constant bias conditions,   self - sustained oscillations are observed in the @xmath0 characteristics of the superlatices in the range of 0.5 to 100  ghz. at the same time, the frequency of the oscillations is found to be dependent on the number of moving charges in thesuperlattice, which can be tuned by varying its doping parameters. as a consequence of the tunneling resonances, it is shown that the drift velocity of the electron wave packet in the current can be varied from 0.1 to 1.0  km / s in the presence of a single tunneling resonance and from 2.0 to 3.0
we present an optical spectroscopic study of 23 low - redshift active galactic nuclei ( agn ) in the extended groth strip ( egs ) using hectospec at the 6.5 m mmt, which has a 1@xmath12 diameter field - of - view @xcite.   we found 31 possible spectral lines for each of the 23 objects, from mgii to , with a range of redshift from 0.2 z @xmath1 0.45 to 0.7 ( c.f. *???   0.8 - 0.9 ).    we find that the average line widths of the observed laes are significantly smaller than those of the high - redshifted laes, and that they are more likely to be narrow - lined than the broad - lined active galactic nucleus ( ciii ) or civ diagnostic lines detected in the x - rays.
hierarchical semi - markov models are deep generalisations of the hierarchical multi - level mixed model ( hhmm ) and the linear - chain mixed model conditional random field ( crf ), respectively.   these models are suitable for data that follows nested markovian processes, in that a state in a sub - markova chain is also a markov chain at the child level. here  , we introduce an approximation technique using gibbs samplers that have the potential of achieving sub - cubic time complexity in sequence length and linear time in model depth. by collapsing all states within each time slice of the dynamic bayesian network ( dbn ), we are able to achieve linear complexity in sequences length, but exponential complexity in depth. as a result, we can model arbitrary depth of semantics for sequential data.
magnetic reconnection frequently occurs at and around magnetic null points in the magnetosphere.   we present an exact expression for the motion of an x - line when its location is constrained to one dimension by symmetry in resistive magnetohydrodynamics ( mhd ). using a three - dimensional model of magnetic reconnection, we show that the motion can be explained by a combination of advection by the bulk plasma flow and resistive diffusion of the normal component of the magnetic field from the weak magnetic field ( high neutral pressure ) side to the strong magnetic field(low neutral pressure)side due to the neutral pressure gradient. during this process,   the current sheet passes through the null point and the reconnection site moves with time as the plasma flow velocity at the null points increases. on the other hand, during asymmetric magnetic disconnection in partially ionized plasmasmas, there may exist neutral flow through the currently ionized current sheet from the low magnetic field side to both the strong and weak magnetic fields ( e.g., from the north to the south ) because of the presence of a plasma - pressure gradient between the two sides of the system. in this work, we find that the
the minimal dilatonic gravity ( mdg ) model is a proper generalization of the einstein general relativity ( gr ).   its purpose is to solve some of the problems, which appear when one tries to describe the nature using gr as a theory of gravity and the standard model of particle physics, and could be a part of a more general theory. in this paper   we review the history of the mdg model and its possible relation with astrophysics and cosmology.
the most popular version of multidimensional ( md ) gravity is a kaluza - klein gravity in which all space - like directions are equivalent, i.e. extra coordinates are the same as the space coordinates.   such approach is very natural but it has a great problem with the sharing of extra dimensions ( ed ). in other words   we should have some natural mechanism for sharing the extra dimensions and space coordinates ; however, it is well known that it is very difficult to realize such mechanism in the empty spacetime. in this paper   there is another possibility for the renewal of the above - mentioned einstein s idea : taking the ed as a gauge group can give us the natural way for the compactification and sharing of the ed.
the optical counterpart of the transient a0535 + 26 be / x - ray binary, v725 tau, was observed on november 7th 1998 using the 4.2-m william herschel telescope at the observatorio del roque de los muchachos, la palma, spain.   the source contains a slowly rotating neutron star in a relatively wide ( @xmath8 ) and eccentric (@xmath9 ) orbit around the b0iiie star v725tau with a radial outflow velocity of about 1.5 km s1 at distances from the star to the equatorial region of the be star. for the first time  , we show the shape of the emission lines seen in the optical spectrum of this system : h@x Math0, h@Xmath12 and @x math136678. when in emission, these three lines sample most of the radial extent of the circumstellar envelope. however, it is apparent that the lines seen here correspond to photospheric absorption from the underlying star as well as some fast - moving material close to the stellar surface.
we have used the discrete dipole approximation ( dda ) to study the extinction properties of composite grains as grain aggregates of amorphous carbon and astronomical silicates, using the transition matrix approach.   we have studied composite grain models with a host silicate spheroid containing n= 9640, 25896 and 14440 dipoles, each carved out from @xmath4,@xmath5 and @x math6 dipole sites, respectively ; sites outside the sp heroid are set to be vacuum ( void ) and sites inside are assigned to be the host material. in the present study, we have compared the model curves with the observed ir fluxes obtained by iras satellite. for the first time  , we use the computer code developed by dobbie ( 1999 ) to generate the composites grain models used in this study. among the three - dimensional models,   the composite grain model with n=14440 has the highest extinction cross section, whereas the other two models have the lowest extinction cross sections. based on the results of our computations, we propose that the effective medium approximation ( emt ) method is not suitable for the study of the extinction property of the composite grains.
electromagnetic waves in the microwave regime play an indispensable role in present plasma experiments.   they are used for diagnostic and heating purposes in low- and high - temperature plasmas, for example, to stabilize so - called neoclassical tearing modes or to investigate the dynamical behavior of the plasma. in all these cases, the microwaves have to traverse the plasma boundary, a region in which substantial density fluctuation levels as high as 100% are observed in fusion Plasmas.    these fluctuations can disturb the microwaved microwaves injected into the plasma or emitted by it and thereby lead to reduced coupling efficiencies to the plasma ( e.g. due to the generation of small scale magnetic islands ) or to ambiguous emission measurements. here  , we investigate the perturbing effect of a turbulent plasma density layer on a traversing microwave beam by means of full - wave simulations. using a full -wave code based on the finite - difference time - domain scheme , we show that the turbulence generated by the turbulent density layer is large enough to disrupt the microwave interaction with the plasma and therefore leads to a disruption of the microwave current drive scheme. when the simulation results are
recent experiments using positron emission particle tracking ( pept )@xcite have observed buoyancy - driven convection in a highly fluidized granular system for a range of grain numbers and shaker amplitudes.   we study the behavior of a model system in which the grains are modeled as inelastic hard spheres. to reproduce the experimentally observed temperature and density profiles, we use values of particle - particle and particle - wall restitution coefficients that were determined by independent experimental measurements. while the model closely matches the experimental system, the velocity field exists for which there is a net circulation with a strong dependence on the particle- and wall - restitution coefficients.. interestingly, the direction and intensity of the circulation are strong functions of the particle - walls restitution coefficient. in addition  , we suggest a modification to the experiment that may generate new convection patterns.
understanding the formation of massive stars is crucial to an understanding of the history of star formation in general and of galaxy formation in particular.   many, perhaps most, stars form in clustered environments where massive stars are present ; however, only massive star formation is readily studied at the distances of other galaxies. here   we consider a number of issues surrounding the formation for massive stars, beginning with a comparison to what we know about low mass star formation, proceeding through some systematic studies of early stages of massive star creation, and ending with some speculations about the initial conditions for massive Star formation.
we study effects of spatial dispersion in atom - surface quantum friction and compare the results obtained using the so - called local thermal equilibrium ( lte ) approximation with those obtained using a full nonequilibrium approach.   we show that spatial nonlocality enhances the failure of the lte approximation, resulting in a 95% deviation from the fullnonequilibrium result compared to the 80% deviation previously reported within local optics @xcite. at short distances from the surface, however, a local description of the material becomes inadequate due to the inclusion of spatial non Locality.. in contrast to the local optics case, where both the Lte and the full none quilibrium approach predict the same distance scaling law for the quantum frictional force, their distance behaviors are different in the presence of spatially dispersion.
we formulate a radially resolved equilibrium model of galaxy formation, in which the equilibrium relations are  local " and functions of ( planar ) distance from the disk centres, and assuming that the gas dynamics is set by the mass - continuity equation and global angular momentum conservation.   our model is self - consistent, as star formation, disk rotation, outflows and the disk size are all set dynamically with the disk evolution. for a single phase interstellar medium ( ism ), we study in detail how systems that follow these simple assumptions evolve, reach a ( quasi-)steady state, accumulate stellar mass, and analyze dynamically their surface density and toomre-@xmath15 profiles. using simplified cases of the full ( partial differential ) equations for our single phase ism, we show that many of our numerical results can be derived analytically.
we study the effect of the squeezed light generated by a subthreshold degenerate parametric oscillator ( opo ) on the squeezing and statistical properties of the fluorescent light emitted by a quantum well in a cavity.   we show that the fluorescence emitted by the quantum well exhibits bunching and quadrature squeezing due to the fact that two or more excitons in the quantum wells can be excited by absorbing cavity photons, which implies that there is a finite probability that two photons can be emitted simultaneously. for a system with a single exciton mode in the opo cavity,   the intensity, spectrum, second order correlation function and quad rature squeezing are obtained using the solution of the quantum langevin equation for a cavity coupled to vacuum reservoir.
the monte carlo method is a fundamental computational tool in science.   its goal is to sample configurations from a given state space from a probability distribution, which can usually not be achieved directly for multi - dimensional distributions. the markov - chain montecarlo methods @xcite overcome this problem by generating configurations starting from an initial configuration which belongs to a simpler distribution and then converging towards the equilibrium distribution. in many practical applications,   it is extremely difficult to decide from within the simulation whether the algorithm has indeed equilibrated the initial configuration. here  , we present a new local - patch algorithm for calculating the convergence properties of markov chains using information on so - called " patches ".    the algorithm is based on a local -patch algorithm, which monitors the entire configuration space of complicated systems, even for very large sizes.. the approach is shown to work for spin glasses at lower temperatures than previous methods, even though the physically interesting regime has still not been reached yet.
the green tensor formalism for the quantization of the electromagnetic field in dielectric media is extended to three dimensions by applying it to the problem of the three - dimensional input - output relations for the electromagnetic - field operators at the boundaries of a planar multilayer structure in vacuum.   the theory is based on a source - quantity representation of the electronic field operators, where the field operators are expressed in terms of a continuous set of fundamental bose fields via the green Tensor of the classical problem. using active light sources at any finite distance from the scattering region, the emitted electromagnetic field is quantized in a consistent way with respect to the ground state and the vacuum region, whereas the evanescent - field contributions generated by radiating atoms that are very close to the bodies under consideration are automatically included in the hybrid quantization scheme.
the neutrino oscillations, which are the disappearance and appearance of different flavors in a neutrinos - produced beam, are one of the major discoveries in particle physics.   the values of the oscillation parameters  two squared mass differences and three mixing angles  are being measured with an increasing precision, thanks to a global effort that produced a number of experiments currently taking data or planned in the near future. within the next two decades  , the precision is expected to be sufficient to begin testing the unitarity of the mixing matrix, discover the neutrinuclear - mass hierarchy and unambiguously determine the value of the dirac phase, violating the charge - parity ( cp ) symmetry of neutron mixing. these results are going to have profound consequences for possible extensions of the standard model, building models of the neutrolytic masses and our understanding of the matter - antimatter asymmetry in the universe. in this topical review,   we discuss systematic uncertainties in ongoing and future long - baseline ( @xmath103001300 km ) neutrini - oscillation experiments using conventional beams using conventional particles  @xcite.
the @xmath3 symmetry of the order parameter ( op ) in high temperature ( high-@xmath4 ) superconductors is nowadays well established by various phase - sensitive experiments.   however, in more recent experiments, several puzzling questions arose. for example a splitting of the zero - bias conductance peak ( zbcp ) was observed even for  tunnel junctions and disorder effects were examined as well in experiment where the disorder of the junctions was increased by ion irradiation. to address these problems we use the scattering matrix approach presented in the theory of quasiclassical green s functions   @xcite to describe surfaces with microscopic roughness. here   we show that the boundary conditions for the theory are not linear on the scale of the coherence length but are instead non - linear depending on the geometry of the interface.. the existence of a zb cp due to disorder is explained by the presence of a subdominant order parameter in the vicinity of the surface.
the highest energy of neutrinos from gamma - ray bursts ( grbs ) is determined by the equilibrium of the cooling timescale and the decay timescale of mesons.   recently, @xcite have shown that the contribution of kaons for neutrino production from jets in supernovae is important. in this letter, using the monte carlo method, we show that the highest energy Neutrinos mainly come from kaons even in internal shocks of grbs. since the temperature of charged mesons will cool down before they decay into neutrines, it is expected that the high energy of neutrins comes from the decay of long - lived neutral kaons. to test this hypothesis, we calculate the spectrum of neut rinos from grbs, taking account of decaying modes of charged kaons into neutrées. also, we consider the contributions of long-lived neutral kaon for neutrin production, which was not taken into account in the previous work. here  , we explain our model and method.
the coherent optical response of photoexcited carriers in bulk systems as well as in semiconductor heterostructures can be studied by means of ultrafast optical spectroscopy.   the life - time of the coherent quantum - mechanical superposition generated by an ultrafast laser excitation, called " dephasing time ", determines the typical time - scale on which coherent phenomena can be observed. since semiconductors are characterized by very short electron - holeDephasing times, of the order of few hundreds of femtoseconds @xcite, coherent phenomena manifest themselves only through ultra fast optical experiments with sub - picosecond time resolutions@xcite. on this time - Scale, the ultrafast evolution of photo Excited electron -hole pairs will reflect the strong coupling between coherent and incoherent dynamics, thus providing invaluable information on the non - equilibrium relaxation processes occurring in the semiconductor, e.g. carrier - carrier and carrier - phonon scattering. in this paper   we review the basic aspects related to coherent phenomena in a variety of semiconductor structures including bulk systems, semiconductor superlattices, quantum wells and wires. after a brief historical account of coherent experiments in solids, we try
the nature of quantum geometry is one of the fundamental issues in the search for a quantum theory of gravity.   it is generally expected that in a full description of quantum gravity the geometry of space - time at small scales will not resemble that of a manifold ; however, the nature of this " quantum geometry " is still a matter of debate. here  , i discuss a specific class of noncommutative geometries which do have the requisite regularization property and discuss how to use them to obtain meaningful predictions from quantum field theory. by means of an approximation technique,   i show that some of the most realistic models of non commutative geometry are not physically realistic ; they generalize euclidean ( space ) rather than lorentzian ( space -Time ) geometry and they are not gauge theories. but   these models may share some characteristics of the characteristics of more realistic models, such as the existence of uncertainty relations between position and momentum.    this suggests that these models can be used to predict quantum field theories.
the ads / cft duality experiment at the relativistic heavy ion collider at brookhaven national laboratory has been used to study the deconfinement transition and quark - gluon plasma ( qgp ) formation. in this note,   i review the connection between the experiments and quantum chemical theory.   since this review is aimed at non - experts, i first give a short course on string theory, in particular emphasizing on how gauge theories and black holes are described in string theory. then, i review recent developments focusing on the @xmath6 gauge theory of qgp. finally, i discuss the role of qcd in these phenomena.
colloidal gels are widely used to stabilize complex product formulations against macroscopic phase separation.   a weak gel, instead of instantaneously settling, hesitates for a well defined delay period before suddenly undergoing a rapid and catastrophic collapse. here   we investigate the mechanism of this delayed collapse in a weak colloidal gel using confocal scanning microscopy and photon correlation imaging. at the micro - scale,   the network of particles is a complex hierarchical structure consisting of weakly connected soft regions of low particle density coexisting with stiff dense strands of spheres which are dynamic and restructured with time, as inter - particle bonds break and reform via thermal reorganization. by measuring the time evolution of the height of the gel, we show that the structural integrity of the network is strongly constrained by the strength and range of the attractive interactions between the gel and the surrounding environment. when the strength of the attraction is comparable to or wide in range, the network undergoes a delayed collapse, which is triggered by a non - equilibrium solid - to - fluid transition, rather than by internal flows or progressive fracture by an applied gravitation stress. from these observations, we propose a theoretical framework for the origin of the delay in the collapse
inflation offers a simple solution to the shortcomings of the standard hot big bang model.   its predictions about the initial density perturbations, leading to the observed structure formation, are in remarkable agreement with measurements of the cosmic microwave background ( cmb ) temperature anisotropies. among the various inflationary models,   one should select the ones which lead to a better agreement with data, with the additional requirement that such models should be naturally built within a fundamental theoretical framework. here  , we propose a model of inflation based on hybrid inflation, where the inflaton field rolls while another scalar field remains trapped in a false vacuum state at the end of inflation. under this model, the false vacuum becomes unstable when the magnitude of the inflataion field falls below some critical value, resulting in the formation of sub - local cosmic strings. by introducing a non - zero constant fayet - iliopoulos ( fi ) term, which can be added to the lagrangian only in the presence of a u(1 ) gauge symmetry, our model avoids the @xmath0-problem, and leads to topological defect formation of semi - local strings.
we investigate the effects of nuclear shape of neutron rich isotopes in the heavy ions reactions.   we use the method of hyperspherical functions ( hsf ) @xcite to construct the densities of the light drip line nuclei near the neutron drip line by using a few one - body harmonic oscillator parameters in order to better reproduce the experimentally observed mean - square radii and density distributions. these densities are then used in monte carlo simulations of nucleon - nucleon collisions, in which the total and inclusive cross sections and transverse momentum distributions of fragments are calculated. for the neutron rich @xmath1li and also @x Math1be, @x math1c nuclei, the results are in reasonable agreement with experiment and other theoretical approaches.
we propose a new model of the primordial phase transition, in which the nucleation rate of a single giant bubble is tuned to give a @xmath3 universe with maximal probability.   the model is based on a tunneling rate tunable in time, and a false vacuum channel to drive the inflation in the parent universe, while a true vacuum channel drives the shorter inflation inside the bubbles. by choosing the peak of the bubble nucleation early enough to have super - horizon - sized bubbles, the model can be chosen to simulate a@x Math3 universe by today, and narrow enough to consider our universe as typical.. the model has been tested on a variety of cosmological scales, including the fundamental scales of the inflation and the remnants of theprimordial phase transitions. for the first time  , we show that the model fits well to the observed data, and that it can be used to explain the evolution of the microwave background isotropy.
soft gamma - ray repeaters ( sgrs ) are a small group of peculiar high - energy sources generally interpreted as " magnetars", i.e. strongly magnetised, slowly rotating neutron stars.   they were discovered through the detection of recurrent short ( @xmath40.1 s ) bursts in the tens to hundreds of kev energy range, with peak luminosity up to 10@xmath5 - 10@ xmath6 erg s@x Math7.    over the last few years the satellite @xcite, launched in 2002 and operating in the 15 kev-10 mev energy region, has provided a wealth of new results concerning the two brightest sgres, 180620 and 1900 + 14. 	 most aspects concerning the sgr's, short bursts, giant flares, and persistent emission, have been investigated, and new results have been found for each of them. here   we will review them here.
the multiwavelength survey by yale - chile ( musyc ) is a deep imaging campaign in optical and near - infrared passbands of four carefully selected @xmath15 fields.   the primary goal of the survey is to study the properties and interrelations of galaxies at a single epoch corresponding to redshift @x Math17, using a range of selection techniques. here   we report our results for the extended hubble deep field south of the ctio 4 m telescope, which covers a square degree of sky to the spectroscopic limit of@xmath10. 	 we show that the number of lyman break galaxies at @x math5 is significantly higher than expected based on cosmology with @x maths12=0.27,@Xmath13, and @xMath14=70km / s / mpc.    we also show that there is a significant reduction in the number and angular clustering of these galaxies with increasing redshift from @x mathematician = 0.28 to 0.11, and a significant increase in the density and angular clustering of @x mathematics = 1.2 times larger than predicted by standard cosmology.
the identity of dark matter ( dm ) and the origin of fermion flavor are still open questions in the standard model ( sm ).   we review some recent studies which have attempted to extend the idea of sm flavor to the dark sector, with a focus on models where dm and the sm fermions both transform under the same flavor group. here  , we briefly summarize some of the most important observables which are likely to be relevant for placing constraints on models of flavored dark matter. among these observables   are the observed relic density of dm from direct detection experiments such as xenon100@xcite and the cosmological constant @xmath3 gev, which is in agreement with the observed value of the dm relic density from supersymmetry experiments. additionally, there are several models of flavor into which dm could be incorporated into which it could play a role. given the multitude of long - lived species in the visible sector,   the assumption of a single particle to explain the entirety of dms may be naive, but at the same time, the existence of three generations of ferns has led to many models of high - scale flavor interactions.
@xmath3 violation is one of the most poorly understood aspects of the standard model ( sm ).   current data merely fixes the value of the violating phase in the ckm matrix, and can not test if this phase constitutes the only source for @x Math3 violation. here  , we show that @xmath0, @x math1, and @x maths2 at a photon collider can provide sensitive tests of @xMath3 violation in the gauge boson sector. using an effective lagrangian approach, we find that these processes are particularly sensitive to the effects of new physics, including interference from the helicity amplitudes of the initial laser light and fermion beams. by comparing our results with those of others in the literature,   we identify features of our analysis that might be useful for other new physics searches using these processes.
quantum information technology has the potential to address problems that can not be solved by standard, classical information technology and to radically improve the performance of existing classical schemes.   entanglement between quasiparticles in meso- or nanoscopic solid state conductors is of particular interest due to the potential for quantum bits based on the spin or orbital quantum states of individual electrons, the ultimate building blocks for solid state quantum information processing. here   we discuss a theoretical proposal for an implementation of a two - particle interferometer ( 2pi ) in a conductor in the quantum hall regime where electrons propagate along chiral edge states and quantum point contacts constitute reflectionless beam - splitters with controllable transparency. as a consequence,   the 2pi could be electrically tuned between with two independent mach - zehnder interferometers and a 2pi. at zero temperature and perfect coherence, both the sources and sites of detection of the two particle interference pattern are visible in the current correlations. under ideal conditions, i.e. 0.5   kj / cm2 coherence and finite temperature, the system is found to be fully entangled, with the source being a single - electron emission from a
the direct kinetic effect of a considerable lepton asymmetry on cosmological nucleosynthesis ( cn ) has been investigated in @xcite, and cosmologic constraints on its value have been obtained.   the effect of neutrino oscillations on cn was also studied and stringent bounds on oscillation parameters were obtained. in this work   we discuss the simultaneous effect of an initially present and dynamically generated leptomolecular asymmetry and oscillating neutrinos and antineutrinos on both cn and helium-4 yield.
the subject of superfluidity in ultracold trapped fermionic gases is an exciting field @xcite, not only for its implications in atomic physics, but also because there are important implications for condensed matter systems, including perhaps high temperature superconductors @xmath2li.   the goal of this paper is to present an overarching theoretical framework for dealing with fermion gases over the entire range of bose - einstein condensation ( bec ) crossover and the entire regime from bcs to bec, as well as the entire spectrum of population imbalance. here   we present the theoretical formalism for the sarma and one and two - plane wave loff states at zero and finite@xmath0 as one varies from bbs to bec.we show that the effects of crossover from bcc to bec can be fully explained by a mean field - like ground state theory based on the bcs - leggett - type ground state, which is consistent with the existence of an intermediate temperature superfluid at @x math7, which has been shown to be stable in the presence of crossover effects. however, it is found that the effect of crossover does not always exist at this temperature, and that the
the slow relaxation of density in granular materials under tapping has attracted much theoretical interest since knight and his collaborators @xcite carried out systematical experimental measurements of density as a function of time for a vibrated granular material.   the experimental data can be most satisfactorily fitted using a functional form of the model : @xmath2}\ ] where@xmath3 is the average density in the system at time instant, @x Math4 is the particle density and @x math5 is the vibrational intensity. in this paper  , we propose a one  dimensional discrete lattice model for granular compaction under tapping based on a simple physical picture which predicts a logarithmic relaxation of the density in a linear manner with respect to the current density. by fitting the model equation to the experimentally measured density relaxation,   we confirm the numerical confirmation of the relaxation as eq.   (  = 0.943 ) in the continuum limit.
zigzag persistence is a new methodology for studying persistence of topological features across a family of spaces or point - cloud data sets.   it generalises the successful and widely used theory of persistence and persistent homology   @xcite, and can handle several important situations that are not currently addressed by standard persistence. in this paper  , we describe how to construct zigzag diagrams of space or vector spaces where each pair of adjacent pairs is connected by a map ( either a map or a series of maps ) : a sequence of spaces with each linking map pointing in an arbitrary direction. using this approach,   we show that the direction of each connecting map is arbitrary, in contrast to the usual theories of persistence where all maps point in the same direction.    we also introduce the _ diamond principle, a calculational tool analogous in power and effect to the mayer   vietoris theorem in classical algebraic topology.
we investigate the possibility of hybrid inflation in string theory using the @xmath0-term inflation model.   we show that the inflaton is driven by supergravity corrections and supergravity - induced interactions with a moduli sector, and that these interactions induce a tree level slope and mass for the infaton. however, when the moduli are taken to be no - scale, the rate of variation of the modulus is small enough to allow us to find a viable slow - roll inflation model with limited fine - tuning of the modulation sector.
we propose a finite - dimensional, short - range interaction model for which the existence of a thermodynamic glass transition is understood theoretically.   we show that the model possesses uncountably infinite number of ground states in the infinite size lattice, and typical ground states are irregular in the sense that they do not exhibit any long - range positional order characterized by bragg peaks. here  , we introduce an overlap with a ground state configuration @xmath2, which corresponds to the magnetization in the ising model. since our model exhibits a glass transition when it is defined on a random graph, we explain the correspondence by reviewing the phase transitions in the equilibrium statistical mechanics.
the aim of mathematical modelling in epidemiology has always been to help predict the patterns of spread of infectious diseases, but the complexity of real populations has always constrained modellers to use strong assumptions.   one of the strongest assumptions used in most epidemiological models is the law of mass action, which assumes that the population has no structure, i.e. that every person can be in contact with every other ('random mixing'). however, in general, members of a population interact only with a very small subset of it ('social network analysis') ; this implies having more data about the social structure, as well as new concepts and tools to analyse them. here   we review the current state of the art in social network epidemiology, and discuss how it can be used to estimate the epidemic threshold of populations whose structure is deduced from sexual behaviour surveys.
a new technique employing velocity centroid gradients ( vcgs ) for tracing magnetic fields in the interstellar medium ( ism ) is introduced in @xcite.   the technique employs velocity gradients that, according to the mhd turbulence theory, tend to be perpendicular to the _ local _ direction of the magnetic field and are therefore useful for tracing the 3d distribution of turbulence in the ism. here   we study the properties of the vcg technique using the galfa 21 cm data from the x - ray diffraction ( xrd ) experiment and the principal component analysis ( pca ) of the spectroscopic data as well as the synchrotron intensity gradient ( sigs ) data. by comparing the statistics of channel maps versus the statistics obtained with velocity centroids   one can expect that the v cgs technique may have advantages for studying supersonic turbulence as it provides a way to identify the regions of the media where the matter is subject to the gravitational collapse. at low sonic mach numbers, the density statistics of the Vcgs are anisotropic compared to those of the sigs which are more sensitive to the density of the medium. however, at high sonic
the total kinetic energy release in the neutron induced fission of @xmath0u(n, f ) is measured for neutron energies e@xmath1 = 3.2 - 50 mev.   the time of flight of the neutrons inducing fission was measured, allowing deduction of their energy and the results are compared with various models and theories of fission.
fullerenes are a class of large and hardy carbonaceous species that have been recently discovered in the planetary nebula tc 1 by @xcite.   they are made of hexagonal and pentagonal aromatic carbon rings, fused in the shape of a hollow sphere or ellipsoid. because of their remarkable stability, fullerene molecules seem particularly suited to survive the harsh conditions of the interstellar medium. here   we review the currently known formation mechanisms of fullererenes in the laboratory and propose an alternative pathway, consistent with astrophysical conditions, based on the photo - processing of a family of carbonaceous products which we name " arophatics " (   /arophatics).we also discuss the observations of these molecules in the reflection nebulae ( rne ) of tc 1 and the photodissociation regions of other evolved star environments.
the hadronic invariant mass spectra of the final state hadrons of the charged lepton and hadronic current are obtained by using the heavy mass expansion for inclusive decays of heavy hadrons.   it has been shown in @xcite that one may resum the leading twist terms into a universal light - cone distribution function ( or shape function ) for the heavy quark, which is entirely non - perturbative and may be written formally as a forward matrix element of a non - local operator. here   we use such an evolution equation and solve it analytically by putting in the one loop result for the anomalous dimensions. to obtain this result we renormalize the shape function so that the effective hamiltonian takes the general form @xmath17 and the hadronic energy is either leptonic or photonic. upon integration   this yields the usual sudakov logarithmic singularities ; however, close to the endpoint the leading twists become very large and hence a resummation of the double logariths becomes necessary since they are process independent. in the present note   these terms are resummed into a shape function for the dark - cone distributions of the
we report an experimental demonstration of quantum teleportation from light beams to the vibrational states of a macroscopic diamond sample of @xmath2 mm@xmath3 in size under ambient conditions.   the vibration states are carried by two optical phonon modes, representing collective oscillation of over @x Math4 carbon atoms. using quantum state tomography, we demonstrate entanglement between the paths of a photon and different oscillation patterns of the diamond represented by two phononic modes. using this entanglements, we prepare arbitrary polarization states for the photon and teleport these polarization states to the phonon mode with the bell measurements on the polarization and the path qubits carried by the same photon.    the teleportation is verified by quantum process tomography and we achieve a high average teleportation fidelity, about @x math7 ( or @x maths8 ) after ( or before ) subtraction of the background noise.
the solar p - mode parameters have been demonstrated to vary with time and to be closely correlated with the solar activity proxies.   these temporal variations provide insights to infer the interior of the sun and its structural and dynamical changes throughout the solar cycle. however, the origin of the variability is thus far from being properly understood and a better comprehension of its relationship with solar ( and stellar ) activity cycles will help us in our understanding of the dynamo processes. here  , we analyze observations collected by the space - based, sun - as - a - star instruments global oscillations at low frequency ( golf, gabriel et al. ) and variability of solar irradiance and gravity oscillations ( virgo, frhlich et al.. ) onboard the _ solar and heliospheric observatory _ ( soho ) spacecraft. for the first time, we show that the temporal variations of the modes excitation and damping parameters from virgo were averaged over the @xmath22, 1 and 2 modes. during the unusually low solar cycle   23, the mean values of the mode amplitudes and linewidths are significantly different from those from golf and virgo. using linear regressions, we
the interface between the a- and b - phase of he  is the only known boundary between two superfluid systems.   the interface motion that accompanies the first order phase transition from the undercooled a- into the b -phase is subject to extended experimental and theoretical investigation.. in the present work, we generalize the hydrodynamic description to interfaces of finite curvature, taking as an example spherical b - phases bubbles growing in a bath of under cooled a - phase. using the radial waves of second sound as the reference velocity, we show that the temperature distribution within the bubble is determined by the time dependence of the radial wave amplitudes, which are also dependent on the growth velocity and the kapitza coefficient. for small growth velocities,   both radial waves remain inside the bubble where neither the temperature nor the magnetization is homogeneous. for higher interface velocites, however, the radial steps are emitted out- and inward, while the temperature remains homogeneous in the a - Phase.
the celebrated kortweg - de vries ( kdv ) equation is a well - studied non - linear dynamical system, first evoked for the description of solitary waves in shallow water @xcite.   it has found much applications in the field of quantum mechanical eigenvalue problem of the reflectionless potential@xcite and in the theory of van alfvn waves in collisionless plasma, phonons in anharmonic lattice, interfacial waves in two - layer liquid with gradually varying depth, transmission lines in schottky barrier and ion acoustic solitons, to mention a few. here  , we show that kdV equation possesses @xmath2-symmetric, localized and cnoidal wave solutions, which appear in complex conjugate pairs.. the existence of these solutions can be traced to the fact that, there are two distinct mkdv equations whose solutions are related through the miura transformation for the solution of kdvs, where, the sum and the differences of the pair are also solutions. this, in turn, generates more general complex superposed solutions for the kDv equation.
hard - core systems are characterized by a close - packing density as the maximum possible density of a given crystal structure.   the hard - sphere fluid has become the canonical model for freezing, since it captures in the most simple form the dominant packing effects while attractive interactions are believed to play only a secondary role. in the present work   we examine the close - pack limit in detail using density - functional theory ( dft ) approximations that have previously been applied to the low - density solid near the phase transition. at physical densities below the space filling density where the particle diameter ( at and beyond this limit @xmath5 is not defined )   there is no solution to the stationarity equation derived from the ramakrishnan - yussouff functional @xcite at any density below the bulk density. on the other hand,   two solid solution branches smoothly connected to each other at low densities which diverge at close packing and are completely isolated from the liquid.see research article http://www.biomedcentral.com/1471-7007/9/8/1
quantum mechanics ( qm ) has been always facing the fundamental critics since its establishment.   the exact physical meaning of " quantum" is unclear, which leads to the well - known " weirdness". in this paper, we show that qm is a special kind of " description" of motion, from which, there is no good or bad of qm and classical mechanics ( cm ). for instance, the state vector in hilbert space can capture the properties of coherence, e.g., interference, which is exotic for cm. on the contrary  , trajectory is the basic idea in cm and the macroscopic world, yet, not in qm, due to the uncertainty. in practice ( reality ), to employ which description depends on its efficiency. by using the path - integral method, which borrows ideas from cm, only has mathematical meaning. in order to test the theory, we first start from one new concept, " scope", to check the foundation of q mr, and then move on to the other concepts, such as nonlocality and entanglement. finally, we present the results of the analysis of the trajectories in the paths - integral
the heterogeneous network ( hetnet ) is a promising paradigm for increasing system capacity and coverage in a cost - effective way.   however, the inter - cell interference ( ici ) potentially introduced by hierarchical layering of cells becomes a fundamental limiting factor to the overall network performance. to cope with ici, fractional frequency reuse ( ffr ), which was originally proposed in conventional macro - only networks @xcite, is considered to be an efficient technique for orthogonal frequency division multiple access ( ofdma ) - based hetnets. in this paper, we present a joint user association and multi - cell frequency allocation scheme for ffr in hetnets. as a simple approach suitable in this homogeneous network  , we can optimize a single parameter @xmath0 to control the bandwidth allocated to universally reused subbands, and then divide the rest of bandwidth evenly among three reuse-3 modes.. the proposed scheme significantly improves cell - edge and median user throughput compared to no frequency allocation, without sacrificing the whole network throughput.    we also provide practical criterion to narrow down the number of candidate patterns to reduce the complexity.
the high - resolution x - ray spectra of the brightest and nearby rs cvn binary systems obtained by   xmm - newton_ and   chandra _ are well - exposed and provide a high signal - to - noise ratio.   abundant coronal elements ( c, n, o, ne, mg, si, s, ar, ca, fe, and ni ) produce a rich spectrum of electronic transitions in the euv and x - rays, allowing us to perform benchmark studies of atomic databases. here  , we use these spectra to determine the elemental abundances of the photospheric and chromospheric regions of the solar corona of active and inactive stellar coronae from the same class of stars, with the aim of understanding the so - called " first ionization potential " ( fip ) effect in the solar wind and corona. for all targets,   the observed abundances are indistinguishable from those of the sun, which suggests that the observed abundance pattern is not due to a fip - related bias, but rather to the presence of an inverse fip effect.
modified gravity is an interesting dynamical alternative to @xmath0cdm cosmology in that it is able to describe with success the current acceleration in the expansion of our universe, the present dark energy epoch.   recently, the importance of modified gravity models of this kind has been reassessed with the appearance of the so - called'viable'@x Math1 models @xcite. these are theories which satisfy both the cosmological as well as the local gravity constraints, which had caused in the past a number of serious problems to some of the first - generation theories, that had to be considered now as only approximate descriptions from more realistic theories. in this paper  , we show that, for some values of the parameters, it is possible to find several de sitter spaces ( as a rule, numerically, for small values of curvature exponent ) ; one of them may serve for the inflationary stage, while the other may be used for the late - time acceleration stage.
we study the electronic excitations in graphene in the field of the aharonov - bohm flux and compare them with the corresponding results for 2d electron gas ( 2deg ) with a quadratic dispersion.   we use the simplest case of magnetic field concentrated in a thin cylindrical shell of small but finite radius @xmath5 when@xmath6 @xcite. using scanning tunneling spectroscopy ( sts ) measurements of graphene flakes on graphite  , we show that the dirac theory of the quasiparticles in the vortex state of high - temperature superconductors is valid under the different conditions. in the case of 2deg,   the results are consistent with the results of sts measurements of pristine graphene.
the gaia space observatory has been operating at the lagrange point l2 for more than a year.   the main product of this space mission is an astrometric catalog ( coordinates, velocities, distances, photometric data ) of a billion stars down to 20@xmath7. in this paper  , we describe the results of a systematic analysis of the data from the gaia project on the search for binary systems among low - luminosity stars. using the fk5 and hipparcos catalogs, we have obtained a large number of images of the solar neighborhood of stars with large proper motions ( > 0.1 arcsec ) and high mass ( > 1.0 m ). by analyzing these images,   we have determined the masses of the components of the binary systems and the orbits of the two stars. as a result, we can estimate the fraction of binary systems in a given stellar population and compare the results with those of cosmogonic models.
the solar cycle and related activity phenomena are correlated with the earth s global climate and temperature, the sea surface temperatures of the three ( atlantic, pacific and indian ) main ocean basins, the earth’s albedo, the galactic cosmic ray flux that in turn is correlated with Earth s cloud cover and, indian monsoon rainfall.   owing to sun s immense influence of space weather effects on the world s environment and climate, it is necessary to predict and know in advance different physical parameters such as amplitude and period of the future solar cycles. in the present study, with an  autoregressive  model and by using the physical parameters of 22 cycles, we predict the amplitudes and periods of future 16 solar cycles from the 22 cycles ( 1755 - 1996 ) sunspot data. a pth order   order _ autore progressive _ model relates a forecasted value @xmath3 of the time series@xmath4 $, as a linear combination of @x Math5 past values @x math6, where the coefficients @x maths7 are calculated such that they minimize the uncorrelated random error terms, @xMath8.. the results show that
we propose a stochastic model of the equilibrium distribution of income and wealth in a single agent framework.   the model is based on the interaction of the agent with the market which is represented by a map of the form @xmath1    where the time index is assumed to be a random function of a single parameter ( time index = 1 ) and the parameters are linear functions of the solution of random difference equations such that for each parameter, the probability density function ( pdf ) of the system is always greater than 1. we show that the model provides a robust and stable description of the distributional features of the income / wealth distributions at different limits and also shows some new features as well. here  , we propose the model and discuss its relative merits and demerits with respect to the kinetic exchange models.
the vaidya metric is a nonstatic generalization of the schwarzschild geometry that describes the geometry of unpolarized radiation, represented by a null fluid emerging from a spherically symmetric source.   it is valid for both ordinary celestial objects and for evaporating black holes ( bhs ). in this paper  , we study the collapse of the null fluid with nonzero radial pressure as the source of the vaidyan metric in the flat minkowski space and its consequences for the model of gravitational collapse in conformal gravity. to study the effects of the collapsing null fluid on the kinematical properties of a timelike congruence of observers, we introduce the imperfect fluid stress tensor and investigate its structure and its relation with the brown - york energy.. the modified quasilocal energy of the voids is also investigated.
a bipolar hyper - shell model has been proposed for the origin of the north polar spur ( nps ), in which the nps and its western and southern counter - spurs are interpreted as due to a dumbbell - shaped shock front induced by a giant explosive event at the galactic center.   we revisit the galactic - center explosion hypothesis using the 408-mhz all - sky radio data and the rosat x - ray images. here  , we show that the galaxy s major galactic spurs both in radio and x - rays are found in the central @xmath4 region around the Galactic Center. based on the results of the winsconsin x -ray experiments,   the northern polar spur is interpreted as being due to an impulsive energy input from a single galactic starburst 15 million years ago. since the cooling time in the halo is much longer than the shell s life time, any of these mechanisms will, however, result in a similar shocked shell in the intergalactic halo, given the same amount of total energy.
we provide a theoretical analysis of the magnetic states and magnetization processes in planar antiferromagnetic superlattices with and without four - fold anisotropy in magnetic fields applied within the multilayer plane.   the results show that the exchange interlayer coupling is an oscillatory function of the uniaxial anisotropies of the ferromagnetic layers coupled through a spacer layer. in the case of weak four-fold anisotsropy ( e.g., fe / cr(001 ) ), the exchange interactions between the two - layers are strongly influenced by the effective uniaXial aniostropy in the layer planes. in high - symmetry multilayers with higher symmetry,   strong biquadratic exchange interactions are not observed. in systems with low - symmetry, however, the effects of the interaction between the three - layer surface and the spacer layers are more pronounced. for systems with high symmetry, the influence of the exchange interaction on the exchange properties is mainly determined by the effect of the fourth - layer anisotropic anisotelectric field on the interfacial exchange interactions. in order to study the complex magnetization process in such systems
rapid stellar evolution is generally accompanied by intense mass loss phenomena.   these phenomena are generally thought to be driven by a non - spherically symmetric dispersion of angular momentum, which is largely extracted from the gravitational and magnetic fields of the source. here  , we review the recent advances in our understanding of the physics of these outflow phenomena and discuss their implications for the overall energy and momentum budget of the star / galaxy formation process.
the active sensor unit ( asu ) for the linear electron collider @xcite consists of a pcb with 1@xmath0 pads plus mesh on one side and asics on the other side.   it was fabricated by the bulk fabrication process, which consists of the lamination of a stainless steel mesh ( 20@x math2 m diameter wires woven to a square pattern ) and photosensitive insulating films onto an anode pcb. in order to improve the accuracy of the measured energy,   the asu has been integrated with front - end asic sensors. at the same time, the detector has been fitted with a high - performance hadron calorimeter ( hcal ) equipped with a tungsten absorber. here  , we describe the assembly process and the results of the first asu.
the seyfert 1 galaxy mcg6 - 30 - 15 at @xmath0 has been the centre of much interest since a broad iron line was discovered in its x - ray spectrum with the _ asca  satellite.   the iron line emission is part of the reflection spectrum produced by the hard x -ray power - law continuum in the source irradiating the accretion disc and is broadened and skewed by doppler, gravitational redshift effects, and light aberration and bending. here   we investigate the spectral variability of the black hole emission in mcg5 - 6 using a simple two component model consisting of a highly variable power - Law continuum and a much less variable reflection spectrum, which of course includes the iron lines. to account for the observed spectral variability, we have assumed that the source of the continuum emission ( assumed to be an isotropic emitter ) changes location close to the blackhole, so that even if the continuum has a constant intrinsic luminosity, it appears to the outside observer to change in brightness because of gravity bending the light rays out of the line of sight by different amounts depending upon the precise location of the source.. the results show that the intensity of the
we present an extended theory of the single - magnet rotary flowmeter and compare it with experimental results.   two limiting cases of long and short magnets are analyzed using linear - dipole and single - dipoles approximations, which allow us to find the equilibrium rotation rate of the magnet at which the torques due to the translation and rotation balance each other. in the first case,   the torque on a magnetic dipole rotating about an axis normal to a thin sheet has been calculated by smythe using an original receding image method. for the second case, the lift force on a magnet moving with constant velocity above a conducting thin plate   is found to vary in the layers of infinite horizontal extent and arbitrary depth, and the drag force on the magnet also varies as the velocity squared in the low - speed limit considered in this paper. both cases are used to obtain simple analytic solutions for the force and torque on slowly moving and rotating magnets due to eddy currents induced by the flow across the magnetic field.
transverse collective oscillations have been recently excited in the radial plane of an elongated cylindrically symmetric condensate @xcite.   they are quasi-2d excitations and indeed, at very low temperatures, the measured frequencies of the transverse monopole and quadrupole modes are found to be in very good agreement with the theoretical predictions obtained by linearizing the gross - pitaevskii equation for a trapped two - dimensional ( 2d ) system. in the present paper   we consider a cylindricalcondensate and calculate at zero temperature the transversal spectrum of excitations, by solving the linearized gross -pitaevskii equation in 2d, and the modes with non - zero momentum @xmath1 along the longitudinal axis, as well.the main purpose of this paper is to investigate the coupling between quasi-3d ( transverse ) collective oscillation and thermal excitations in the collisionless regime. using the landau damping as a decay mechanism of transverse collective modes as a function of temperature, we find that the decay rate of the singular transverse breathing mode is one order of magnitude larger than that of the monopole mode.
the richardson exact solution of the pairing hamiltonian is given for the many - body pairing in ultra - small grains system @xcite.   the continuum is included by enclosing the system in a large spherical box and taking the derivative of the phase shift for the continuum part of the single particle level density. to avoid the fermi gas, we parametrize the cspld for the resonant partial waves and make the analytic continuation to the complex energy plane. using the eigenvalue equation as the antisymmetrised product of the two wave functions, we derive the exact eigenenergies of the coupling between the low lying states of even carbon isotopes.
cyg x-1 is a persistent x - ray source believed to be powered by accretion onto a black hole from a massive companion.   it is in the hard state for most of the time and sometimes switches to the soft state. on april   21, 1999, two strong outbursts of gamma - ray bursts ( grbs ) were detected in the batse data during search for non - triggered gamma -ray bursts. we analyze the temporal structure of the events in the four lad energy channels 14, estimate the peak luminosity of cygx-1, and discuss possible implications for theoretical models of accretion in this object.
we present our results for the calculation of the contribution of the @xmath3 resonance to pion production in mineral oil.   these results are compared with the experimental data obtained by the miniboone collaboration  @xcite, which is a group that has developed a general simulation code for inclusive pion nucleus reactions using the model at the nucleon level of ref.@xmath0-induced onepion production cross sections in minerals oil ( @x Math1 ) for neutrino energies below 2gev and the resulting pion final state interaction ( fsi ) of the final pion as a function of the nuclear environment.
rotational brownian motion of colloidal particles is a classical subject in statistical physics.   the importance of this motion for the theoretical description of the often complex and surprising hydrodynamic and magnetic properties of ferrofluids was recognized already a long time ago. in the present paper   we show that a suitably designed time dependent external magnetic field can rectify the fluctuations of the particle orientation and set up a  noise - induced  rotation of the ferromagnetic grains. to test this theory we investigate how angular momentum can be transferred from an oscillating magnetic field to a Ferrofluid at rest. using two different approximations of the relaxation dynamics of the magnetization, i.e., neel - relaxation and dipole - relaxation, we find that the latter is more difficult to achieve with the help of a non - rotating magnetic field due to the imposed non - zero flow vorticity of the carrier liquid. on the other hand  , the former is much more straightforward and can be achieved with the use of a time - dependent internal magnetic field without a net rotating component.
we recently demonstrated that the laser - induced nonresonant polarizability interaction can be used to influence the internal rotation of an axially chiral molecule around the stereogenic carbon - carbon ( c - c ) bond axis of a substituted biphenyl molecule in space, using laser induced alignment by a long laser pulse.   this enables a much shorter fs pulse, which we will refer to as the kick pulse, to both initiate torsional motion and set the molecule into rotation around the fixed axis. here   we extend our previous work on the manipulation of the internal rotational motion of @xmath3 by a ns laser pulse for 3,5-diflouro-3,4-dibromo - bipenyl ( dfdbrbph ) by using a transient modification of the field - free potential curve by a fs kick pulse. with the help of quantum chemical calculations  , we show that the angle between the two phenyl rings of the molecule is controlled by a short fs pulse polarized perpendicular to the central stereogenic axis of @xcite. at the same time, the external degrees of freedom of the molecules are manipulated by a longer fs pulse oriented along the
scale relativity allows one to give foundations to the postulates @xcite and motion equations of quantum mechanics, and to gauge theories of particle physics, in particular to electromagnetism, by providing them with a geometric interpretation in the framework of a fractal space - time.   we have therefore been able to derive the schrdinger equation, which applies to non - relativistic particles, the free klein - gordon and dirac equations, and finally the pauli equation, that is the non - relativistic limit of the dirac equation, from the first principles of scale relativity. here  , we show that these equations can be recovered by combining the scale covariant derivative and quantum covariant velocity operator, i.e. extracting the square root of the bi - quaternionic electromagnetic klein-gordon - like equation for a spinless particle submitted to an external electromagnetic file.
we study the inductive bias of convolutional arithmetic circuits, a class of networks that are gaining increasing attention in recent years.   we show that the network s pooling geometry effectively determines which input partitions are favored in terms of separation rank, i.e. the possibility of exponentially high separation ranks for certain input partitions, while being limited to polynomial or linear ( in network size ) separation scores for others.    we empirically validate our results with both convolutionic arithmetic circuits and rectified linear ( relu,  convolved linear ) and polynomially sized rectifier networks. using a set of different partitions of input regions into disjoint sets, we find that a deep network supports exponentially high separability ranks for some input partitions but not for others, while limiting its ability to support linear separation ranks only for some partitions. on the other hand,   an exponential separation rank is required for all input partitions to be separable from the closest separable function w.r.t. by a given partition of input, whereas a linear separation rank can be obtained for only a small fraction of the partitions. as a result, we argue that the choice of partitioning geometry determines which
the local electromagnetic field acting on an atom in a material medium differs from the macroscopic one due to the gaps between the atom and the surrounding medium atoms.   accounting for the difference between the two fields hence requires a correction  the local - field correction. using the real - cavity model, toma @xcite studied the spontaneous - decay rate of an excited guest atom embedded in a dielectric host body, which is located at the center of a dispersing and absorbing dielectic sphere, and assumed a real cavity surrounding the atom. by reformulating the result by representing it in a form which does not explicitly refer to the highly symmetric system considered, he made the conjecture that it may also remain valid beyond the specific example and hence also apply to other locations of the atom or other shapes of the host body. in this paper, we present an attempt to overcome this problem by writing the green tensor as a born series in terms of the susceptibility, where in many situations one can restrict oneself to several leading - order terms. to linear order  , we show that the spontaneous emission rate of a guest atom with respect to the decay rate in free space can be separated into a term representing the local
we study the emission of few emitters in a cavity, with particular focus on the photon statistics of the emitted light.   our goal is the characterization of temperature and coupling regimes where nonclassical light  @xcite  is generated. at strong coupling,   the master equation for the interaction of two - level emitters with a single cavity photon mode is replaced by a master equation expressed in the photon - dressed emitter eigenstates. to understand the relevance of the different approximations involved in traditional quantum optics treatments  , we compare the results that are obtained when the counter - rotating light - matter interaction terms are included in the hamiltonian to those when they are dropped.the results obtained with the full master equation with results from the quantum optical master equation show that the correct master equation is still needed at weak coupling.
ionizing radiation is extensively used for cancer treatment in radiation therapy.   the ionization or excitation of the dna molecules, either directly or indirectly, can lead to dna single or double strand breaks which can cause carcinogenesis in normal cells or lead to fatal damage in normal or cancer cells. in this work, we apply a quantum physical description of molecular interactions to propose a mechanism that could allow the manipulation of dna radio - sensitivity induced by ionizing radiation using the pauli exclusion principle and the bohr magneton as a control system.
the lognormal distribution of correlated random variables is an important property of the central limit theorem for modeling fluctuations of the energy cascade rate in turbulence.   the lognormality is a consequence of the kolmogorov s 1962 theory, which shows that the averaging scale of the correlation function @xmath2 is comparable to the large scale ( e.g., the correlation length ) of the velocity correlation function@xmath4 and the squared velocity increments over distance @x Math0   ^ 2 d x \label{du2}\end{aligned}\ ] are logn Wormally distributed when the averaged scale @x maths2 is set to @x math3.    we consider yet another example of lognorman example in turbulence, which was recently found experimentally @xcite. 	 it is observed that the coarse - grained squared velocity and squared velocity increment over distance //{\frac {du2 }-5 }-6 } ] are Lognormally distributed
we investigate the possibility of using polarized photons to study the structure of medium - heavy nuclei.   we use a nuclear model recently developed to investigate electromagnetic excitations of the nucleus in inclusive, single and double coincidence @xcite experiments. by using this model to describe nuclear excited states we treat the meson - exchange currents ( mec ) by considering one - pion exchange diagrams. by implementing the short range correlations ( src ) acting on one - body electromagnetic currents, we improve this picture by calculating all the diagrams containing a single correlation line. for the @xmath4 reactions, we find that photoemission cross sections have a greater sensitivity to src than electron scattering cross sections. at photon energies above 100 mev and for proton emission angles above 80 degrees,   the src effects are relevant at the same time as the mec effects.
we report the first spectroscopic detection of the companion star in j2123 - 058 and its radial velocity curve using the fors-2 spectrometer of the _ kueyen _ vlt.   the observed radial velocity curves are consistent with the mass determination of @xmath13 0.07 m@xmath8, which is consistent with a low mass x - ray binary ( lmxb ) consisting of a neutron star and a late - k companion. to obtain this mass we need to know both the system inclination and the mass ratio as well as the amplitude of the radial velocities of the two stars. by combining these data with the analysis of the emission from the companion during quiescence, we obtained the following results : ( 1 ) the system has a mass ratio of 0.7  :  0.3 and an inclination of ~1.0  km/s.    ( 2 ) the radial velocity of the secondary star is proportional to the mass of the main star and the angular separation of the center of gravity from the central axis of the primary star. on the other hand, the radial speed of the partner star is not proportional to its mass but rather to the
we study the evolution of cosmological one - dimensional perturbations when both baryonic and dark matter are considered.   we use two different methods for solving the hydrodynamical equations : eulerian and lagrangian. in the first method,   the effects of low density regions are studied using mesh - based methods @xmath4 and in the second one using particle methods @xcite. to explore the differences in the statistical properties of the two methods, we compare the results obtained at different scales and find that the latter have the advantage of giving a higher resolution where needed without having, in one - dimension, the same problems of grid distortion present in more dimensions.
the quantum electrodynamical cross section for resonant compton scattering at the cyclotron resonance in the high - field regime is derived using the sokolov & ternov ( st ) and johnson & lippman ( jl ) wavefunctions, which are eigenfunctons of the kinetic momentum operator and the magnetic moment operator, respectively.   the cross section is derived by incorporating the line widths that originate from the lifetimes of the excited landau states in the qed cross section. to use such widths in spectral calculations in astrophysical models, it is important to use basis states that yield a spin dependence that is lorentz invariant, i.e. boosts along the magnetic field do not lead to a mixing between the spin states. as is true for all quantum processes, the spin - dependent decay rates and cross sections depend on the choice of electron wavefunction in a uniform magnetic field. given the different spin dependence of the st and jl eigenstates, one must use caution in making the appropriate choice when treating spin-dependent processes. here  , we show that the st state is the most appropriate choice for this purpose because it diagonalizes
the appearance of laser sources with ultrarelativistic intensities has opened real possibilities for revelation of many nonlinear electrodynamic phenomena at the interaction of superpower radiation fields with high brightness accelerator beams, relativistic plasma targets of solid densities, and qed vacuum.   nevertheless, the actual way to get net energy exchange of relativistically electrons is using of coherent processes of laser - particle interaction with the additional resonances. among those the induced cherenkov, compton, and undulator processes are especially of interest. in this review   we will consider laser - induced processes on free electrons with the large effective gain of interaction due to nonlinear resonance achieved in the given field of a strong laser radiation. in the induced Cherenkov process,   the intensity of the laser field is confined by ionization threshold of dielectric dielectrics, whereas in theinduced compton process the intensity can be controlled by the presence of an additional resonance ( e.g., in a static magnetic field ) where the particle - wave interaction cross section enhances by many orders of magnitude. in order to achieve high net energy change of particles, specifically for laser acceleration, or free electron laser ( fel ),
quantum walks are quantum mechanical properties that can be used to perform quantum computation.   the most important of these is the @xcite algorithm, which can factor integers and search an unsorted database respectively, significantly faster than the best known classical algorithms. in this paper  , we show the equivalent construction of a universal gate set using the discrete time quantum walk in place of the continuous time walk in order to perform a quantum walk on an unweighted graph of bounded degree, @xmath1-vertex, where the input is a qubit input from a quantum computer. by using a simple rule to compute the neighbours of any vertex at any vertex, the quantum walk can be performed on the same structure as the one described in @xcitesite, but with a maximum degree of eight at any vertices.
plankton patchiness is a common feature of planktonic systems.   many model systems have been put forward to explain pattern formation in these systems, but the important effects of noise have usually been neglected. in this work  , we analyze the effects of non - diffusive advection and diffusion on the formation of patterns in plankton population dynamics using satellite imagery and spectral analysis. by taking into account the spatial heterogeneity of the plankton species, we show that the inclusion of diffusion and advections in the models of population growth can generate patterns in the absence of noise, which are dependent on the size of the population and the spatial resolution of the environment. for example, if the concentration of phytoplankton is reduced to a few millimeters per day, the intensity of patchiness increases with the number of years since the last time the population was sampled, the amplitude of the patchiness decreases, while for the same number of days, the magnitude of the patches increases.    the results of the spectral analysis of satellite images suggest that the spatial scale contribution to the total patchiness may be much greater for zooplankston than for phy toplanktons.
many important problems in the theory of integrable systems and approximation theory can be recast as riemann - hilbert problems for a matrix - valued unknown, in which the solution matrix is sectionally holomorphic and the number of poles is not fixed in the limit of interest.   these problems can be solved asymptotically by pre - existing " steepest - descent " methods, which involve making a local change of variable near each pole in some small domain containing the pole at the cost of introducing an explicit jump on the boundary of the domain around the pole in which this transformation is made. here  , we review the history of the use of these techniques to study riemans - hilsbert problems with more complicated problems.
we report results from co@xmath24 observations of two massive galaxies at @xmath1 using atacama large millimeter / submillimeter array ( alma ) to study the spatial distribution and the kinematics of molecular gas in the starburst cores.   we find that the central regions of the galaxies are strongly attenuated by dust @xcite, which is a result of efficient energy exchange with hot dust during the formation of the starbursts. moreover, the surface brightness of the co - based gas mass increases more rapidly than the gas mass surface density in the center of the dense cores. these findings are consistent with the model that assumes a chabrier initial mass function ( imf ; [@xcite ) ) and adopt cosmological parameters of @x Math25 = 70 km s@x math9 mpc@xMath9, @x maths26=0.3, and @x mathematics27 = 0.7.    the observed changes in the co surface brightness suggest that the core formation rate is much higher than previously thought.
the discovery of a bright gamma - ray burst ( grb ), 080916c, by the recently launched fermi satellite is an important advance toward our understanding of these spectacular explosions.   a number of different proposals have been put forward for the generation of high energy photons in grbs. in this letter   we provide multiple lines of evidence that show that high energy photon and late time x - ray and optical afterglow emissions from grb 080516c were produced via the electron synchrotron process in the external shock ; lower energy photons ( @xmath3mev ) had a different origin. in the next section  we provide a summary of the observed data forgrb 0809 16c. in   the first section we describe the expected high energy emission from the externalshock and compare that with the data for grb 010020gev, and in the second section we show that the entire optical and X - ray aftergl glow data for this burst is consistent with the external Shock model. using the externalShock parameters determined from the late Afterglow data alone  , we show also that the expected emission at @x Math5mev during the prompt phase
a hamiltonian formulation of problems is often advantageous, since equations of motion can be easily obtained from a scalar function representing the total energy of the system.   the main reason why symplectic integrators ( sis ) have become so popular over the past decades lies in the fact that they offer remarkable long - term energy conservation. in this paper   we present a systematic way to construct high order sis for three part ham Miltonian systems. using two different hamiltonians as examples  , we show how high order symplectic integration methods for these kinds of systems can be constructed. using a toy model and the disordered discrete nonlinear schrdinger equation as showcases, we compare triple split methods with respect to their computational efficiency and energy Conservation.
the equilibrium phase diagram of the ultra  thin magnetic film @xcite is studied in detail in the region where the change in the relaxation properties has been observed.   we show that for very low temperatures metastable states appear, which generate blocking clusters of the metastable phase where the domain walls of the stable phase become pinned by the magnetization of the system. using monte carlo simulations we study the dynamics of the magnetic domain growth or coarsening dynamics of this system when it is quenched from a disordered state to a subcritical temperature below the ordering transition for different values of @xmath4 and show that the results are strongly affected by the presence of metastable regions of the lattice where the domains of the striped phases are pinned by the structure of the supercooled phase.    such blocking clusters generate free  energy barriers to the domain growth dynamics that are independent of the linear domain size.
the origin of the cosmic - ray emission from supernova remnants ( snrs ) has been elusive, despite many decades of attempts and controversial claims.   we report on a low - energy @xmath3-ray and multiwavelength spectrum for the snr w44 in order to constraint the emitting particle spectrum and discriminate between leptonic and hadronic models. at low energies ( 50 - 100  mev )   it is possible to observe the presence of accelerated hadrons and the interplay between hadronic and leptonal models.
recently, mnard et al. ( 2010a : hereafter msfr ) investigated the distribution of dust around galaxies by measuring the angular correlation between sdss galaxy distribution and distant quasar colors.   they found that the mean @xmath1-@xmath2 reddening profile around sdss galaxies is well approximated by a single power - law : @x Math3 where @x math4 is the angular separation between foreground galaxies and background quasars.  in practice, it is difficult to distinguish between the circum - galactic and inter - stellar dust models on the basis of the statistical correlation analysis alone as performed by msfr. therefore a complementary and independent method to constrain the nature of the dust is needed. in this paper  , we measure the dust far - infrared ( fir ) emission of the sdss Galaxy sample by image stacking analysis. using the sfd galactic extinction map, we show that the detected fir emission from the same galaxy sample as the msfr reddening measurement puts a constraint on the dust temperature, which would in turn offer complementary information for distinguishing between the two models mentioned above.
we present the simultaneous broad - band pulse profiles and spectral characteristics of the pulsar igr j16393 - 4643 obtained from a _ suzaku _ observation.   we also present results from the orbital intensity profile analysis using _ swift - bat _ light - curves. for the first time  , the energy resolved pulse profiles are created for this source with respect to the phase averaged as well as resolving the pulse phase into peak phase and trough phase. these results provide valuable insights into the nature of the underfilled roche lobe supergiant systems.
the electromagnetic gauge invariance of the transverse polarized drell - yan ( dy ) hadron tensor in the deeply virtual compton scattering ( dvcs ) is investigated in the light of the qed gauge invariances, the causality and gluonic pole contributions.   we show that to restore the gauge invariant expression for the transversally polarized dy process, it is mandatory to add the extra diagram contribution to the single spin asymmetry ( ssa ) due to the hard perturbative gluon loops or twist three contribution of the pion distribution amplitudes. at the same time, we demonstrate that this new contribution is directly related to the certain complex prescription in the gluonal pole of the quark - gluons of the function @xmath4 which is involved in the hard part of the mechanism of the two - particle correlator contributions.
we provide a hierarchic analysis of chaotic scattering in hill s problem by studying a slightly different scattering function, giving the dependence of the dwell time on the initial conditions, combined with a careful examination of scattering orbits.   this method has recently been applied to a simple model of chemical reactions making properties of the hierarchic organization clear in that problem.
we present preliminary thermal model fits for 13511 main belt asteroids ( mbas ) observed during the 3-band cryo phase of the wide - field infrared survey explorer ( wise, *??? * ) mission and the neowise post - cryo survey.   the diameter of the objects is estimated from the thermal emission of the telescope @xcite, which was used to constrain the size of the blackbody flux in the w3 band. using the calibration data obtained from the 2nd and 3rd bandpasses of the wise survey, we find that the mean albedo of the largest mbas detected during the fully cryogenic portion of the probe is ~2.0  0.9  cm3 and the mean diameter is ~1.8  1.6  cm4.
broadband molecular line surveys are an effective tool for investigating the rich molecular inventory of star - forming regions@xcite.   these surveys are often made available to the public, which allow for other researchers to pursue more detailed investigations or to search for new molecular species in the data. here  , we present early results from a spectral survey toward sagittarius b2(n ) acquired using the heterodyne instrument for the far infrared ( hifi)@xmath aboard the herschel space observatory@xaite. by providing a census of which molecules are emitting in each frequency range, this survey can be used to aid in characterizing the submillimeter spectra of other molecular clouds. with the help of a number of computational tools,   we present an analysis of the emission spectrum of methanol in this spectrum, which is detected through a large number of transitions ranging widely in frequency and excitation energy.
the vertical structure of radiation pressure - supported accretion disks is investigated by taking into account the local energy balance and to study the variation of energy advection with mass accretion rates.   we consider a steady state axisymmetric accretion disk in spherical coordinates and use the newtonian potential, @xmath23, to model the hydrostatic equilibrium in the center of the disk. for a typical radius@xmath21, the vertical structure and the energy advesction   are investigated, and the two - dimensional solutions and the convective stability are studied. using the density as a parameter, we find that the volume of the central part of the space is dominated by the energy adsorption from the viscous heating, and that the temperature of the surrounding space is controlled by the advective cooling. on the other hand,   the surface of the black hole is not affected by any of the above conditions.. the results are consistent with the results of the spin measurement of the active galactic nucleus.
we derive governing equations for two counter - propagating electromagnetic waves interacting with plasmonic oscillation - induced medium polarization in a bragg structure containing thin films with metallic nanoparticles.   this system of equations represents the two - wave maxwell - duffing type model. using computer simulations, we find exact solitary wave solutions of this system and analyze stability of these solutions.
anisotropic flow, in particular elliptic flow, is a signature of collective flow in nuclear collisions at high energies.   it is very sensitive to the equation of state which governs the evolution of the system created in the collision and provides important information on the state of matter under the extreme conditions of the nuclear collision. here   we present a new study of the anisotropy of @xmath0 for light nuclei in the target rapidity region using a forward hodoscope to determine the event plane at the atomic force microscopy ( afm ) at the spin - state superparamagnetic resonance ( sps ) as a function of centrality for protons and pions.the results are compared with those of previous studies at the ags and sps.
the confinement mechanism of the @xmath3 dimensional non abelian gauge theory with an adjoint higgs field - the georgi - glashow model - is studied using semiclassical methods.   the structure of the effective lagrangian in pure gluodynamics is explicitly determined by the spontaneously broken magnetic@xmath0 symmetry, and the results show that the confinement mechanism is realized as confinement of topological solitons for those vortex fields. in the presence of fundamental quarks, the vortex field is no longer a local field, but is instead a gauge coupling gauge, the value of which is inversely proportional to the mass of the ( lightest dynamical quark ). here  , we show that this gauge coupling coupling is gauged by the existence of a conserved baryon number charge, which is represented in the low energy theory, and will be shown to have a bag - like structure in the case of finite energy baryonic states.
we present an experimental study on the formation of bubbles resulting from the collision of a sessile drop with a moving meniscus.   we show that air bubbles can be entrapped during this collision, when the contact takes place at or very close to the moving contact line ( i.e. at @xmath0, with the impact height with respect to the substrate being about 1 cm above the moving substrate ). in this case,   the bubbles form by reconnecting capillary waves that result in toroidal bubble rings as described theoretically @xcite. however, it has been predicted that bubbles can also be formed during a coalescence with zero impact velocity, for which no lubricating film develops. in order to test this hypothesis, we measured the size of the entrapment bubbles, as a function of impact velocity and impact height, and found that floating bubbles are the most common type of bubble formation.
the minimum - cost flow ( mcf ) problem is a well - studied problem with many applications, for example, modeling transportation and communication networks. over the last half century   many algorithms have been developed to solve it.   the network simplex ( ns ) algorithm has the best worst - case bounds on its running time, but in practice it performs much better than the minimum - mean cycle canceling ( mmcc ) algorithm. here  , we analyze the performance of the ns algorithm and the mmcc algorithm in the framework of smoothed analysis. using smoothed input models for the mcf problem, we show that the ns can run in strongly polynomial time in practice, while the mmCC algorithm runs in strongly Polynomial times in theory. however, the relative performance of these algorithms in practice is completely different. in order to better understand the differences betweenworst - case and practical performance for the ns and mmcc algorithms, we perform smoothed analyses of the two algorithms in the context of the smoothed output model. by comparing the performances of the three algorithms in terms of their worst- and best - case running times,   we find that there are instances for which the ns outperforms
we present a simplified model of heat transport between two thermal baths at different temperatures.   the simplicity of this model allows us to gain a better understanding of : ( i ) system statistics during a large deviation event and how it reflects the time reversibility of microscopic dynamics, and ( ii ) finite - size corrections to the direct evaluation of large deviation functions in computer simulations.the model consists of a single lattice site characterized by an energy @xmath6 which is coupled to two thermal bath systems, namely, one at room temperature and the other at room pressure. using the fluctuation theorems @xcite, we calculate the probability of having certain configuration at the end of a large deviations event and for intermediate times, while we analyze their relation in terms of the reversibility with respect to microscopic dynamics.the results show that the simulation results are consistent with the predictions derived from the additivity principle and the hydrodynamic fluctuation theory, and that the calculated current distributions are in good agreement with the results obtained using the gallavotti - cohen fluctuation theorem.the existence of simplified models for which exact solutions can be obtained is essential to elucidate the origin and importance of these finite - sizes corrections in simulations.
we investigate the consistency requirements for the effective phantom dark energy in the scalar - tensor gravity.   we find that models with the present phantom de can be made consistent with all constraints, but one of the functions entering the lagrangian must have rather specific shape, and the initial data must be strongly fine - tuned. also, the phantom stage must have begun fairly recently, at @xmath0.
classification is an important task in many fields including biomedical research, engineering, sociology and many others.   how to construct a classification rule based on a labeled data set is a classical statistical problem. recently, due to technical innovation,   " big data" becomes a buzz phrase in many field, and we now often encounter with data sets that have huge amount of unlabeled data. because to label each unlabeling subject is usually costly and inefficient, a common approach is active learning. since data are observed adaptively, this type of methods are also related to the stochastic approximation process, which was first discussed in @xcite. in this paper, we present a novel modification of active learning algorithm, which combines the logic - maximum likelihood estimate of a logistic model and d - optimality design for bayesian estimation of generalized linear model ( glm ) under sequential experimental design. using the proposed method, we show that the learning process can be effectively stabilized when the number of dimensionality of the unknown vector of parameters becomes large.
the cambridge pulsar array is a meridian - transit instrument consisting of 4096 full - wave dipoles operating at a wavelength @xmath5 m. it has been used to search for pulsars since 1968, and the discovery of psr  j0437@xmath14715 by johnston _ et al.   ( 1993 ) demonstrated the existence of at least one very strong, nearby, millisecond pulsar. in this article   we describe the design and operation of a new pulsar search at 81.5mhz using a modified set of 16 beams generated by inserting an extra phase gradient in the north - south direction across the entire array, thereby shifting each beam north by half a beamwidth, or about @x Math8.    we find that the new search is successful, with the detection of six pulsars : ps b0329 + 54, b0809 + 74, b0834 + 06, b0950 + 08, b1133 + 16, and b1919 + 21. among these,   ps b0729 + 53 is the most powerful, with a peak power response of 1.6 times that of ps b0129 + 52.,
quantum dots are artificial electron systems ( es ) realizable in modern semiconductor structures.   the relative strength of the electron - electron and electron - confinement interaction, given by the ratio @xmath4, can be varied, even experimentally, in a wide range, so that the dots are used to be treated as artificial atoms with tunable physical properties. until recently most theoretical work was performed in the regime of strong magnetic fields, when all electron spins are fully polarized. in the past three years a growing interest is observed in studying the quantum dot properties in zero magnetic field @x Math5 @xcite. at the present time, however, results obtained by different methods contradict to each other, and full understanding of physical properties of@xmath6-electron quantum dots at @x math5 has not yet been achieved. here   we review the available data on the ground state energy of a three - electron quantum dot in 0.1  m zeta potential, as a function of the interaction parameter @x maths7, and discuss the possible existence of a transition from a partly to a fully spin - polarized ground state caused by the intra - dot coulomb interaction.
the transmission coefficient is the dynamical correction of the transition state ( ts ) dividing surface in molecular dynamics.   there are different formalisms for the transmission coefficient formula which differ in the way trajectories are counted. in this article   we discuss the standard bennett - chandler ( bc ), the history dependent bc ( bc2 ) and the effective positive flux ( epf ) formalisms and show that the latter should always be preferred due to a lower average pathlength and a faster convergence. however, whenever a lot of correlated recrossings occur, the transmission coefficients will be very low and all these methods become inefficient. in high dimensional complex systems it can be a very difficult task to find a proper reaction coordinate ( rc ). moreover, whenever the dynamics is diffusive, even an optimal rc can result in a very low transmission and hence a poor efficiency. here  , we present a benchmark system for which the efficiency of the methods can be calculated analytically with only a few approximations. by allowing the pathlength to vary and by counting only positive effective crossings, the overall reaction rate in transition interface sampling ( tis )   is found to be significantly higher than that in transition
we have developed a dynamical model to extract the magnetic dipole(m1 ) and electric quadrapole(e2 ) strengths of the @xmath1 transition from the pion photoproduction data at legs and mainz@xcite, and for pion electroproduction at thomas jefferson national accelerator facility(jlab)@xaite, mit - bates@xcites and nikhef@xcits. in this paper  , we report on the progress we have made in extending the sl model to investigate the pions electroproduction reactions in the @Xmath8 excitation region.   we will make use of the recent data from jlab and mit-bates to explore the q@xmath2-dependence of the #9 transition and make predictions for future experimental tests.
rotating ideal fermi gases of spin polarized particles rotating with frequency @xmath1 are investigated in the presence of a quartic term to the trap potential.   the trapping frequency is chosen to be close to the radial trapping frequency, i.e.@xmath2, and the rotation frequency is considered to be fast ( ~1.5 kcal / mol ) when the trap configuration is set to an anharmonic trap. for the fast rotating system,   it is possible to experimentally observe the formation of vortex arrays where small - amplitude oscillations, so called tkachenko modes, are observed as a function of the rotation rate. at low temperatures, these modes are essentially non - interacting due to pauli blocking and the fact that p - wave interactions are negligible in such systems. however, due to the fermion pressure, particles tend to avoid the center of the trap, so that, effectively, a statistical interaction arises even in the case of an ideal gas, which bears some analogies with repulsively interacting bosons. in this work  , we show that the existence of the tkacs mode is not only possible in the context of the bose - e
the global monopole, which has divergent mass in flat spacetime, is one of the most interesting topological defects in cosmology.   we study the gravitational field of global k - monopole in vacuum manifold and derive the solutions numerically and asymptotically. for a model in units of units of time, where a global @xmath5 monopole is considered, we find that the topological condition of vacuum manifold for the formation of a k-monopole is identical to that of an ordinary monopole ; however, the physical properties of the two types of monopoles are very different. especially, we show that the mass of the global k-- monopole can be positive in some form of the non - canonical kinetic terms, i.e., the gravitational potential can be attractive or repulsive depending on the type of non -canonical kinetic term. by comparing theoretical value to the observed rms fluctuation,   it is shown that the solution of the cosmological evolution of a global k--- monopole will be quite different from those of ordinary ones.
the velocity dispersion of main sequence stars in the solar neighbourhood increases with advancing spectral type.   this increase in velocities depends on the roughness of the gravitational potential in the disk, so knowledge about the shape of the velocity ellipsoid will tell us a great deal about the dynamical history of a disk. in this pilot study   we show that it is possible to derive the three - dimensional shape of an intermediate - inclination galaxy by using the fact that the velocity dispersions at different galactocentric azimuths show different projections. for the large early type spiral ngc 488,   the results show that the distribution of the radial and azimethal velocity dispersive dispersion in the plane of the galaxy varies with the intrinsic position angle from face - on to edge - on as the galaxy moves closer to the heliocentric plane. when the rotation speed is measured along the major and minor axes the radial dispersion is found to be more elongated than the azimithoracic dispersion, whereas when the star rotations are measured at the minor axis the radial dispersements are more elongate. these results are consistent with the observation that the density of the
a graph - based approximation scheme for the minimum dominating set of a unit disk graph   @xmath7 is proposed.   the algorithm receives as input the adjacency representation of the graph and assumes no knowledge of the point coordinates, whereas the geometric algorithm works in the real ram model of computation and receives solely the vertex coordinates as input.    the proposed algorithm runs in @x Math2 time, and the geometric algorithms run in @Xmath4 time regardless of @x math8.. the performance of the proposed algorithms is compared with that of previous algorithms.
optomechanics with superfluid he is a very attractive system because of its intrinsic nonlinearity.   it is known to have acoustic phonons with almost zero friction at low temperatures, a finite value arising only from thermal three - phonon scattering processes. in this paper  , we present theoretical foundations of the optomechanical interactions between the electromagnetic fields and the superfluid density in terms of the quantum mechanical properties of the electromagnetic and fluid fields as well as the classical semiclassical equations for the optical cavity resonance per photon. by means of the hamiltonian formulation of the problem,   we derive the canonical form of the linear interaction hamiltonians for the spectroscopic measurements of the resonances per photon in the cavities like a fiber cavity or a superconducting resonator. using these parameters, we obtain estimates for the strength of the photons and phonons interactions in the cavity.    in addition, we estimate the single step two - phonone antistokes process due to acoustic nonlinearness and two - step two-phonon processes due to the intrinsic nonlinearlyity of the superfluids.
local - field corrections to the bulk modification of the spontaneous emission rate in free space can be ascribed to two effects associated with the bulk ( macroscopic ) field in the medium and the local ( microscopic ) field.   the bulk field correction multiplies the rate by the refractive index at the transition frequency @xcite and the quantum local - field correction arises from writing the local electric field in terms of the macroscopy electric field and the induced polarization field. here   we investigate the changes that arise within the clausius - mosotti model when the fluctuating component of the medium polarization is included in the quantization scheme used for calculating the modified spontaneous decay rate, which is consistent with quantum emission theory ( qed ). a scheme for quantizing the electromagnetic field in an arbitrary linear dielectric medium has been proven to be consistent with qed and used for calculation of the modified spontaneously emission rate including the local quantum effects of the fluctuated medium polarization. using this scheme, we show that the observed emission by atoms embedded in dielectrics is not due to the local fluctuations in the electromagnetic vacuum but to the transient absorption losses caused by the dissipation of the local polarization induced by the local environment
we present a new approach to the calculation of the fermion damping rate for the production of photons by a quark gluon plasma.   we show that the contribution of the self - energy diagram evaluated at finite temperature @xcite, which is dominated by the thermal mass of the static magnetic ( transverse ) modes, is infrared finite, and that this is due to kinematical constraints on the contributions of the exchange of exchanged gluons in the hard quark loop. as a consequence, it is possible to regularize the heat - induced infrared singularities by resummating the thermal masses of the hard thermal loops on the quark propagators, which can be obtained by using the re - resummation of the hot thermal mass given by the resumption of the soft thermal loops in the limit.
evolutionary game theory ( egt ) predicts that the evolutionary trajectories of the rock - paper - scissors game will cycle around the nash equilibrium persistently.   however, no persistent cycle has been confirmed in the traditional setting of the rps experiment under which the game is decentralized. in this work   we carry out laboratory experiments on the standard rps game using a non - equilibrium order parameter to detect the possible existence of persistent cyclic flows in the evolution trajectories and compare our results with the predictions of the discrete - time logit dynamical process with a noise parameter. by using an angular frequency as the non - equilibration order parameter, we are able to confirm that cycles exist and do not dissipate. for each round of the game,   the mean frequency of cycles is about @xmath1 period per experimental round ; this mean value is used to evaluate the noise parameter of the logit dynamics model, and a value of@xmath4 is obtained.
the viscous fingering instability of radial hele - shaw flows involving non - newtonian fluids is studied using a weakly nonlinear approach.   we focus on the onset of the nonlinear effects, and try to understand how mode - coupling dynamics leads to basic morphological features such as dendritic fingers and side branching. in the case of shear thinning,   the transition from a single stable finger in the rectangular geometry to a patterned finger with spreading and splitting of the finger tips is observed.. however, when the fluid is shear thickened, the fingering becomes more complex, and the growth rates are dramatically increased, leading to the formation of different types of fingering patterns. by taking the displaced fluid as non -Newtonian, we show that both the initial and final stages of evolution are nonlinear, and that the modes of interaction between the two fluids are highly divergent. for the first stage of the process, the rate - dependent changes in the viscosity of the fluid   are most pronounced in the radial setup, while for the second stage they are more variable in the rectangles.,we find that the phase - coupling behavior is dominated
the lightest supersymmetric particle ( lsp ) is the gravitino, which is a candidate for the cold dark matter in the universe.   it decays efficiently in the main detectors if the decay length is sufficiently short, @xmath11 ( 10m)@xmath12, where the number of produced susy particles is calculated. on the other hand, for typical susy production cross sections,   a direct observation of the decay is very difficult for ~14 sec. here  , we consider the physics of the charged superpartners ( cnlsp ) that can be studied with a heavy material stopper  detector  at the large hadron collider at cern ( lhc )  @xcite. the lifetime of the long - lived charged nlsp ( cnlsps ) is determined by measuring the mass of the graviton and the decay products of the neutralino and the lightest scalar tau, which are stopped by the ionization loss in the material. to study the lifetimes of the cnslsps, we propose a stopper consisting of a tracker and heavy stopping material, which can measure the arrival time and the location where
the solar neutrino flux measurement at the synchrotron x - ray observatory ( sk ) in cielab, brazil, has been running since the end of sk - i@xcite.   it is now well established that the best solution of the solar neutrolytic oscillation is msw - lma ; this is strongly supported by many experiments results. to realize this goal, reducing background and systematic uncertainty below 5.5 mev and lowering the recoil electron energy threshold are important. here   we describe some of the improvements we have made to reduce these uncertainties since sk - iii.
we develop a general methodology for designing learning algorithms based on a minimax analysis.   we first convert online learning problems into variants of drifting games, and then apply a minimx analysis and relaxations to recover existing algorithms and design new ones with special useful properties. using this general idea, we show that it is possible to recover many existing algorithms from an online learning problem and design them with optimal regret rates. in particular, we derive a generalized notion of regret ( @xmath0-regret, defined in our drifting - games framework ) that measures how good the algorithm is compared to all but the top @x math0 fraction of candidates.    we also show how to relax the original minimax analyses step by step to reach a general recipe for designing hedge algorithms ( algorithm  ).. our new algorithms are totally parameter - free, which is usually not the case for algorithms derived from a minimX analysis. moreover, we also derive high probability bounds for the randomized hedge setting as a simple side product of our framework using any concentration results.
the large deviation functional derived from the non - conservative stochastic dynamics in @xcite is used to calculate the large deviations of the injected power for a different type of dissipative system.   the results show that the local conservative current fluctuations are produced by a different mechanism than in the case of conservative dynamics. for some choice of the glauber rates, the steady state may exhibit a phase transition leading to a new kind of dynamical phase transition for the current which is presented in section . using the exact expression of the large deviation function, we discuss its symmetry properties with respect to time reversal and recover the fluctuation relation for the entropy production.
we present a new method to generate a dark optical ring potential ( orp ) by means of the phenomenon of conical refraction ( cr ) @xcite, occurring in biaxial crystals.   cr leads to a set of two concentric bright rings enclosing a dark ring of null intensity, known as the poggendorff dark ring ( pdr ). both theoretically and experimentally  , we show that the pdr is a toroidal dark focus. for ultra - cold atoms,   the p dr can be used as a blue - detuned orp for atom trapping and demonstrate this with a @xmath0rb bose - einstein condensate ( bec ).
the @xmath0-mechanism is the excitation mechanism of stellar oscillations that is related to the opacity behaviour in ionisation zones.   this mechanism occurs when the opacity varies during compression phases so as to block the emerging radiative flux from the ionisation region, leading to a strong increase in opacity that leads to the local excitation of modes. for classical cepheids that pulsate in the fundamental acoustic mode, this transition region is located at a temperature corresponding to the second helium ionisation. here   we investigate the influence of the opacity bump on the stability of radial modes propagating in a purely - radiative and partially - ionised layer of a 1-d star using direct numerical simulations of the @x Math0-Mechanism with convection. by simulating the behavior of the transitions between the quasi - adiabatic interior and the strongly non - adsorbed surface, we show that the presence of an opacity bump at the transition region results in the formation of a new equilibrium field that is more stable than the one at the other two driving zones.
we propose an effective hamiltonian approach to investigate the decoherence of a quantum system in a non - markovian reservoir.   the formalism is based on the notion of an effective reservoir, _ i.e., certain collective degrees of freedom in the reservoir that is responsible for thedecoherence.    we show that the reduced dynamics of the open system is completely positive and the complete positivity is naturally imposed from the effective hamiltonsian approach. as examples, we study the evolution of a single - mode atomic cavity in a common thermal reservoir @xcite.
the existence of extreme - energy cosmic rays ( eecr ) with energies above the greisen - zatsepin - kuzmin ( gzk ) cutoff  @xcite of about @xmath2 ev, presents an outstanding problem.   nucleons and photons with those energies have short attenuation lengths and could only come from distances of 100 mpc or less @xcite, while plausible astrophysical sources for those energetic particles are much farther away. in this work   we derive a lower bound on the neutrino mass that is consistent with the published agasa spectrum at @x Math4  ev.    we also find that the observed ee events in even the hires data set remain unexplained since the local universe ( @x math3  mpc ) is devoid of strong candidate sources.
the stabilizer formalism allows for efficient simulation of error correction on a classical computer of operators from the clifford group operating on states stabilized by pauli operators.   the standard error model is a depolarizing channel that simulates common laboratory processes such as dephasing and serves as a good approximation for most error processes that lead to a steady - state in which the system becomes maximally mixed. however, if an error channel is far from unital, then simulating it with p Pauli errors gives large approximation errors making it hard to extract useful results. in this paper  , we show that adding clifford errors and/or measurement errors always results in more accurate approximations and results in significant improvements for most general error channels.
the mode - coupling theory ( mct ) of the liquid - glass transition has been extensively studied in order to compare its predictions with experimental data and computer simulation results @xcite.   most of these tests are based on the use as fitting functions of the quasi - universal laws that are obtained from an asymptotic analysis of the family of non - linear equations to which the mode - coupled equations belong and that are valid only in the vicinity of the predicted so - called ideal glass transition singularity. for experimental data,   this is essentially the only practicable approach, since typical glass - formers are molecular liquids for which a first - principle study is out of reach and since most experiments, like dynamic light - scattering spectroscopy, probe complex mechanisms in which various types of dynamical processes are entangled. in the case of computer simulations, the situation appears more comfortable, since simple systems can be considered for which all the data needed for an extensive comparison with the theory can be directly obtained with high precision. however, it turns out that one still has to rely on asymaptotic results of the theory at some point. for these reasons  , it appears desirable to have a means to test the mct on
the formation of a three - dimensional wall or " brane" is one of the most interesting possible sources of radiation in quantum gravity, from the point of view of both physics and cosmology.   the standard model fields are confined to a 3-d defect in the higher - dimensional space ; only gravity can propagate in the other dimensions or " bulk".this paper surveys broadly the circumstances and the values of parameters the number and the size of large extra dimensions, and the scale of unification for which the background might be detected with current technology.the theoretical framework for the formation of the brane+bulk configuration is based on the assumption that the metric during the unification era must be chaotic on the mesoscopic scale of the horizon at unification, and that it must be close ( within a few orders of magnitude ) to equilibrium at the unification energy scale of about 1 tev. as a consequence, the theoretical model has to be able to predict the existence of gravitational waves at the time of unification by observing the effects of the metric on the cosmological structure of the vacuum vacua formed during the process of the set - up of the new brane.in this paper, we show that theoretical models of the
the spontaneous formation of a regular, rotating vortex lattice in polariton condensates has not been observed experimentally.   the aim of this paper is to study the robustness of such lattices, and to discuss how one may overcome the difficulties that might arise in detecting a rotating vortex - like lattice. using the complex ginzburg - landau equation ( cgle )  , we show that the presence of pumping and decay does not significantly modulate the steady state of the cgile.. however, the presence or absence of pumping leads to a significant change in the stability of the trapping potential. as a result, the polarization of the polaritons becomes nonuniform and the locking of the trapped vortices becomes more complex. by taking into account these changes,   we find that the rotation of the vortex lattices is robust to deformations of the circular harmonic trapping potential, and that it is possible to detect a rotating Vortex lattice with high confidence.
electron scattering is one of the most important processes in determining the emergent thermal spectrum from models of optically thick accretion discs around black holes and neutron stars.   incoherent ( compton ) scattering in the disc surface layers by thermal electrons can reduce this spectral hardening by increasing the energy exchange between the photons and the plasma. in this work   we explore the effect of bulk, turbulent electron motions on photon spectra in black hole sources with radiation pressure dominated accretion flows where bulk speeds may exceed thermal electron velocities. for near eddington accretion on black holes of all mass scales,   the radiation to gas pressure ratio of the innermost disc will generally exceed the proton to electron mass ratio for near - eddinton accretion even for stellar mass black holes, and certainly for supermassive black holes. in these sources,. however, bulk comptonization by turbulence may dominate thermal comptonisation in controlling the shape of the spectrum emitted by a local patch of the disc.
recent afterglow observations of short gamma - ray bursts ( sgrbs ) have provided various information about their environments which can be interpreted as circumstantial evidence linking them with mergers of compact binaries such as double neutron stars ( ns - ns ) and black hole - neutron stars.   however, the compact binary merger scenario is challenged by the detection of jet breaks in the afterglowing of some s grbs and the deduced small jet opening angle of @xmath0.. the formation of such a collimated jet in compact binary merging has not been clarified yet.,1 in this letter, we numerically investigate the jet propagation in the material ejected by double neutron star mergers based on a scenario indicated both by our latest numerical - relativity simulations and the observations of sgrb 130603b. using the observationally consistent parameter set,   we show that relativistic jets successfully break out of the dynamical ejecta and travel with the required collimation angle.
complex networks have been conjectured to be embedded in hidden metric spaces, in which distances among nodes encode their similarity and, thus, their likelihood of being connected.   this hypothesis, combined with a suitable underlying metric space, has offered a geometric interpretation of the complex topologies observed in real networks, including scale - free degree distributions, the small - world effect, strong clustering as a reflection of the triangle inequality, and self - similarity. here  , we present a general and versatile class of weighted networks embedded inhidden metric spaces. built upon the so - called _ newtonian _ class of binary networks in hidden metrics spaces, our framework preserves all the qualities of complexTopologies embedded in underlying metric spaces and, in addition, it allows to enforce explicitly the strength ( sum of weights of a node ) distribution and the correlation between the strength and the degree of nodes. moreover, the level of coupling between the weights and the underlying metricspace enables to control the local disparity of the weights associated to the nodes as well as the shape of the weight distribution. using our model, we find strong empirical evidence of metric properties in real network topologies and weighted structure.
effective field theory calculations in warped higher dimensional spacetimes are particularly complicated.   we use the ads / cft conjecture to inspire the form of a concrete and explicit renormalization group ( rg ) procedure, but do not rely on any unproven aspects of the conjecture.we present a wilsonian rg flow of effective field theories in rs1-type geometries of varying radius, @xmath0, theories with smaller @x Math0 having lower warped down effective energy cutoffs. using this flow,   two effective theories lying on the same flow are matched to describe the same physics at energies below the lower of the two associated adiabatic cutoffs for the same r2 = 0.5.    we show that formally the flow of hidden brane lagrangians looks like a wil Smithsonian rg flow as well as a local 4d rg flow, which greatly simplifies power - counting calculations in such cases. 	 we identify a conformal fixed point in the rg as the concrete realization of the ads/cft connection within our formalism.we apply our results to rederive in a simple way the goldberger - wise stabilization mechanism when the bulk scalar is identified with the one
the detailed properties of the excitation spectrum of excited heavy - light mesons ( @xmath6 ) and their hadronic transitions are yet to be fully understood. in this paper   we use a dirac equation for the light quark in the potential generated by the heavy quark to compute the masses and wavefunctions of the excited states.   these masses and waves are then used to estimate the hadronic decay amplitudes of excited dark mesons in the context of a chiral quark model.    we present numerical results for the low - lying spectrum ( excited states up to the 3s states ) and for the pseudoscalar meson hadronic transition for these states as a function of the chiralQuark model effective coupling constant. comparing our results with recent experimental width measurements  , we find that the average decay amplitude for the 1s and 1p states is ~1.2    0.5  kcal / mol and ~0.9   0.4  mmol / mol, respectively.  also, we estimate the effective coupling between the quark and the pseudo - calcar meson for the 2s state.
tidal dwarf galaxies ( tdgs ) are tidal gas - rich galaxies that have been observed in the arp 181 system and possibly a third small galaxy.   we present one of the most spectacular cases of the impact on high - resolution optical ( hi ) of a tidal interaction between a pair of spirals, ngc 3212 and ngc3215, which make up the arP 181 system. to analyse the structures, we produced image cubes of different resolutions by tapering the data with different uv limits and using uniform weights for the high resolution maps. from these cubes   the integrated velocity field maps were extracted using the aips task ` momnt'( using a 3@xmath9 cut - off ). from the integrated   images, we created image cubes based on the flux density uncertainties of the uv data obtained from the giant metrewave radio telescope ( gmrt ) observations of the system at a redshift of 0.0316 @xcite. as a result of the integration of the data, we find that the total mass of the two spirals is about 1.5 times higher than the estimated value of ~1.0 solar in the damped lyman
electron spin resonance ( esr ) in the field - induced critical phase, especially around quantum critical points, of one - dimensional quantum spin systems is less studied by theorists.   this situation is in contrast to the fact that esr of the @xmath0 heisenberg antiferromagnetic ( haf ) critical chain whose low - temperature esr is well understood. in this paper  , we consider an @x Math0 haf chain with a general form of a single - ion anisotropy in the whole range of the magnetic field, from zero field@xmath10 to the saturation field@Xmath8.    in particular, we focus on a shift of the resonance frequency caused by weakly anisotropic spin - spin interactions. in each region, we introduce an effective field theory and apply it to the analysis of the esr shift. in the case of the gapped region,   the effective field theories are applied to the study of esr shifts in the regions near the lower critical field and the region near the upper critical field. at the same time, the form factor perturbation theory   @xcite ( ffpt ) is used to analyze the
the well - logging technique has proved adequate for oil exploration and production.   parallel to the research of oil and gas fields, some features of petrophysical quantities obtained by well-logging could be analyzed and described in terms of the kind and content of the fluids within the pores. in this study, we use well log data from a gas well in southwest of iran to investigate the spatial heterogeneity of the properties of the large scale porous media, such as porosity, density, and the lithology at distinct length scales using the probability density function ( pdf ) and non - gaussian degree, @xmath0, based on tsallis entropy which is an important bases in thermodynamics.. the results show that the gamma emission ( gr ), sonic transient time ( dt ) and neutron porosity ( nphi ) of the formation are significantly correlated with the temperature and the density of the pore space at the depth range of @x Math19 to @xMath20.    the latter is explained by the fact that the intensity of the interactions between the formation material and the fluids increases with the depth of the well and the concentration of the fluid in the pores decreases with increasing the depth.
the orbital evolution of a low mass x - ray binary ( lmxb ) system, which shows x - rays in its light curves @xcite, has been studied by comparing the mid - eclipse times of two eclipses during the second and the current outburst of this source.   the results show that the orbital period of the source has changed from an initial period of @xmath47.1 hr to an eclipse duration of@xmath415 min, which is consistent with a simple orbital decay as suggested earlier by @xcitesite.
the electrochemical deposition of copper deposits from aqueous solutions in quasi - two - dimensional geometries is an easily accessible growth phenomenon of such an interface.   the focus of this paper is on the electrodeposition of finger deposits @xcite : after the addition of a small amount of an inert electrolyte like sodium sulphate to a copper sulphate solution, the morphology of the copper deposits changes from a typical fractal or dense - branched red copper structure to some fine - meshed texture with a fingerlike envelope. when considering that the fluid between the copper filaments contains no gel, the ensuing situation resembles the saffman - taylor instability, where a more viscous fluid is pushed by a less viscous one and their interface develops the same type of fingering. in this paper   we use that idea to measure the strength of an effective surface tension associated to the hydrogel - water interface by analyzing the dispersion relation using particle image velocimetry ( piv).the results show that the surface tension of the interface is strongly influenced by the density - driven convective currents in front of the growing deposit. if convection is suppressed by turning the cell in a vertical configuration,
the mid  infrared emission bands at 3.3, 6.2, 7.7, 8.6, 11.3 and 12.7   are ubiquitous in the interstellar medium ( ism ).   their carriers are very small grains ( or big molecules ) heated transiently by the absorption of a single uv or visible photon. here   we present mid  ir spectrophotometric and co(21 ) line observations of another reflection nebula, ced201, that shed light into the transformation of these carriers into aromatic infrared bands ( aibs ) when going from strong to weak radiation field in the reflected nebula vdb17 = ngc1333. for the first time  , we observe a broadening of the aib spectrum with increasing radiation field as the radiation field increases. this broadening is due to the release of aib carriers from carbonaceous grains during the transition from a weak to a strong radiation field. on the other hand,   the flux ratio between the two types of carriers decreases with increasing intensity of radiation field but does not change with increasing strength of radiation fields.
a quantum game @xcite describes the strategic interaction among a set of players sharing quantum state(s ).   it turns out that under certain situations sharing of an entangled quantum state can put the players in an advantageous position and more efficient outcome(s)of the game can then emerge due to non - classical aspects of the shared quantum system. here   we consider two - player games that can be played using the setting of generalized einstein - podolsky - rosen experiments ( peres, chsh, cereceda, halliwell1,halliwell2 ) and find the sets of games for which the strategies can exist as nash equilibrium ( ne ) only when bell s inequality is violated. by identifying such games, we show that there exist strategic outcomes that can only be realized when the relevant quantum probabilities relevant to the quantum system that two players share to play the game are violated.
the lambert w function is the inverse function of the mapping of the two branches of the @xmath2 polynomial function, which is used to solve the problem of the transcendental equation.   it is one of the most well - known functions in the mathematical community, and has been extensively studied in the last 20 years or so. here   we present a fast and accurate numerical implementation of the lambertw function for the solution of the euler - lambert problem using the gnu scientific library ( gsl ) special - functions part of the mathematics software tool @xcite. with the help of the command - line utility ` lambert - w `,   the program can be run in a few seconds on a c++ compiler.
we report here on a similar analysis of images of the subaru / xmm - newton deep survey ( sxds ) field, which is located at high galactic latitude in the southern galactic hemisphere.   we find that tens of thousands of stars have proper motions in the images, and we use artificial stars inserted into the raw images to estimate the completeness of our sample as a function of magnitude and motion. using these observations, we compare the observed set of moving stars with those predicted by various models of stellar populations in the milky way.
the crab pulsar ( psr b0531 + 21 ) is a young radio pulsar with a spin frequency @xmath2 and frequency derivative @x Math3.   its characteristic magnetic field is about @x math4 at the magnetic poles. in this paper, an updated pulsar wind model is built based on previous researches and it includes : ( 1 ) both magnetic dipole radiation and particle outflow, and their dependence on the inclination angle ; ( 2 ) the primary particle density may be much larger than the goldreich - julian charge density ; ( 3 ) the effect of pulsar death is considered in modeling the rotational evolution of the pulsar ; ( 4 ) this model can calculate both the spinning down and the braking index values between glitches. to date, only eight pulsars have measured the meaningful braking indices for they are young and own relatively larger@xmath15.. their braking indices are all smaller than three which means that there are other physical processes needed to slow down the pulsa. in order to explain the braking indices observed between glitches, we propose a new model that takes into account the acceleration of the magnetosphere as well as the spin - down behavior of the
the origin and nature of the anomalous 511 kev gamma - ray emission from the galactic centre ( gc ), the characteristic signature of positron annihilation, has been a matter of debate since its first detection in the 1970s.   the most detailed map of the emission to date shows that it originates from the central @xmath01.5 kpc of the gc ( @x Math2@xmath3 ) of the galaxy, with a fainter component of flux detected from the remainder of the galactic disk. here   we review the current state of knowledge on the origin and distribution of this emission, and discuss the possible contributions of a large number of discrete but unresolved sources.
the burrows - wheeler transform ( bwt ) is a widely used preprocessing technique in lossless data compression.   it brings every word into a form which is likely to be easier to compress and its performance is almost as good as ppm ( prediction by partial matching ) schemes while its speed is comparable to that of lempel - ziv algorithms. here  , we discuss bijective versions of the bwt which are one - to - one correspondences between words of length @xmath0. in particular, we give an alternative description, a proof of its correctness, and more importantly, draw connections between scott s algorithm and other results in combinatorics on words such as the sort transform ( st ), which is also known under the name schindler transform ( sht ). for each of these transformations,   we present constructive proofs for the injectivity of the respective transforms.
consumer reviews are invaluable as a source of data to help people form opinions on a wide range of products.   the value and diversity of these opinions raises two questions of interest to us : ( 1 ) how can we help users navigate massive volumes of consumer opinions in order to find those that are relevant to their decision? and ( 2 ) how do we address specific queries that a user wishes to answer when evaluating a product?   we see several reasons why reviews might be a useful source of information to address product - related queries, especially compared to existing work that aims to solve q / a - like tasks by building knowledge bases of facts about the entities in question.
we have updated our compilation of galaxy redshifts for 4076 a- and 54% of all 1174 southern s - clusters from the catalogue of abell, corwin, & olowin ( 1989, aco ).   this is the only such compilation that includes both a- as well as s - cluster redsh shifts. in order to merge galaxy data from different sources for the same cluster,   we need individual galaxy positions, velocities, and errors. using these data, we calculate @xmath8 and@xmath1 for each cluster component. since 1989  , we have also compiled a large number of velocity dispersions for subclusters : 1245 ( sub)clusters with @x Math1010, of which 276 have @x math1050 ( the typical minimum for dynamical studies ), and 95 ( sub]clusters have @Xmath11.. the total number of galaxies involved for all our listed ( sub)(clusters ) is @x maths556,800 ( 9500 of which in s - clusters, including some overhead for overlapping clusters for which it is not possible to assign galaxies uniquely to one cluster ). here
we present a new method for calculating the diffusion constant of a mobile impurity as a function of temperature in the quantum critical regime.   this diffusion constant can be measured directly in experiments with quantum - gas microscopes by evaluating the mean square displacement of the impurity atom from its initial position after a time. using the boltzmann equation, we show that the situation with impurity motion is not as universal, and the impurities time scale is determined by an interplay between several couplings which are formally irrelevant at the critical point. among these couplings   are the inverse effective mass of the mobile Impurity and the associated energy of the gapped excitations above the ground - state. here   we find that the transport coefficients of the two - particle bound - state can be computed reliably using the so called ads / cft correspondence, which maps the strongly coupled conformal field theory to a dual, weakly coupled gravitational theory, where transport coefficients can be calculated reliably.
the well known two - mode gaussian squeezed states of light are physical realization of the einstein, podolsky, rosen ( epr ) state.   quantum correlations of the entangled epr state have been implemented experimentally for massless particles : photons. in this paper   we show that it is possible to construct a quantum witness operator, closely related to the hanbury - brown and twiss ( hbt ) interference, that probe entanglement of a mixed epr gaussian state. using hong, ou and mandel ( hom ) interferometry  , we discuss the entangled properties of time resolved interference of the Epr state.we show that the deep in hom interference can provide a useful tool to study quantum separability of continuous - variable gaussian epr states.
we investigate the strangeness contributions of the weak vector current of the neutron and proton to the magnetic moment of the proton using chiral perturbation theory ( chpt ).   we find that the electromagnetic form factors of the nucleon are the most sensitive to strangeness - violating form factors, which break the isospin symmetry of the quark model wave function in the form of a weak electric and magnetic field due to the electromagnetic and weak vector currents, respectively. by taking advantage of the high - energy nature of the low - energy observables, we show that these form factors are not affected by convergence problems and that they can be calculated in su(2 ) chpt with good agreement with experimental results.
the global financial crisis that started in 2007 has stimulated an extensive literature on numerous credit - related themes such as risk assessment, financial contagion, regulatory indebtedness or liquidity ratios, misuse of derivatives.   this paper contributes to this academic discussion by using a network - based framework to examine the structure and inner dynamics behind the links between financial institutions in different countries. using balance sheet data from 2005 to 2010 from five emerging countries : argentina, brazil, mexico, south africa, and taiwan, we construct simulated banking functional networks from the leverage dependence across financial institutions, and analyze the structure of this networks. despite the absence of actual interbank contracts, these findings translate into relevant policy implications in terms of contagion and concentration, as well as potential avenues for future research.
gamma - ray bursts ( grbs ) are the most powerful explosions in the universe, and are considered to be a possible source of ultra - high energy ( uhe ) cosmic rays.   the anita experiment is a nasa long duration balloon experiment that searches for coherent, impulsive, broadband radio emission ( 200 - 1200  mhz ) from electromagnetic showers induced by uhe neutrinos interacting in the antarctic ice sheet. here   we report the results of a search for uhe neutron emissions from grbs using anita - i, which is a more sensitive search for these events than the previously reported diffuse uhe neutrino search with anita-ii.    we find that the search is successful when the time window given by the burst duration is short enough to allow us to lower the analysis threshold and look for very weak signals which also have a time and direction correlation with the observed gamma - ray burst.
@xcite density matrix embedding theory ( dmet ) is a novel and promising tool for the treatment of strong - correlation in electron systems.   it has been benchmarked for model 1d and 2d one - band hubbard lattices,@xcite and in chemical systems. in the present work, we further investigate the properties of this novel methodology and show that it allows us to gain full control over the lattice filling by breaking spin symmetry in the underlying lattice mean - field solution used to construct the key ingredients of the procedure. using an extended cell formalism, we show that the effective bath basis is sufficient to limit the density matrix fitting to diagonal elements, i.e., we propose, what we call _ density_, as opposed to _ density matrix _ embedding. here  , we provide a detailed numerical analysis of the results obtained with this approach and benchmark the aforementioned approximation against high quality reference data and exact solutions for energies, two - body correlation functions, and compressibility.
superconductivity in cuprate materials still poses many questions that lack a theoretical understanding.   one is about the maximum value of the critical temperature for superconductivity ( @xmath0 ) that could be achieved due to the pairing mechanism, which also concerns the effects that limit @x math0 in practice. in this paper   we propose a mechanism for light - induced superconduction based on the competition between bond - density wave ( bdw ) correlations and superconductivities, which may be applicable slightly above the equilibrium @x Math0 where the system is close to a bdW instability.    we describe the interplay of bd w and pairing fluctuations with a phenomenological non - linear sigma model   @xcite, and investigate the external driving of this model by coupling it to phonons via electrons. as a result  , we find evidence for a transient superconducting state induced by light in underdoped yttrium  @xcite ( ybco ) and lanthanum  ->cyanoacrylate ( lco ) based cuprates far above @x maths0, and even up to room temperature in the former case.. the
human activity and item popularity are two perspectives of the cross links between users and items in social media networks, such as youtube, facebook, delicious, amazon, flickr and wikipedia.   it is widely believed that information can spread quickly along social links using user - to - user exchanges, also known as " word - of - mouth " exchanges ; moreover, the users behaviors are strongly influenced by their neighbors @xcite. however, how these two distributions arise simultaneously due to human activity has yet to be determined. in this paper  , we first characterize the evolution of human activity anditem popularity in the amazon ( n=7,911,684 ratings, 267,320 movies and 759,899 users ), fl Flickr ( n = 497,937 users, 11,232,836 photos and 34,734,221 favorite - markings ) and delicious (n=132,500,391 bookmarks, 50,221,626 urls ( books ) and 947,835 users ) networks.    it is found that in such social media network, both relative probabilities of users creating cross links and items acquiring cross links are proportional to the degree of activity and degree of
we investigate the effects of the nambu - goldstone bosons on the spectral density of the longitudinal gluon in a two - flavor color superconductor @xcite.   we show that the gauge bosons corresponding to the five broken generators of the original gauge group give rise to a longitudinal degree of freedom for the gluons of adjoint color 8, which is physically related to fluctuations of the order parameter, in our case the diquark condensate, in directions in color - flavor space where the effective potential is flat. using a suitable choice of ( t  hooft ) gauge, we find that these modes can be eliminated by reducing the qcd coupling constant and the quark chemical potential.
we present a computational framework for the inclusion of a general fluid / solid interaction, treated as a temporally and spatially dependent body force, in a direct solver of the navier - stokes equations.   this approach allows for computing fluid wetting properties ( such as equilibrium contact angle ) based on first principles, and without restriction to small contact angles.
complex metabolic networks, modeled as bipartite graphs, are of particular interest due to the availability of high quality reconstructions based on complementary sources of experimental data, and the possibility of experimentally validating computational predictions. here   we explore the metabolic networks of two bacterial organisms, staphylococcus aureus and escherichia coli, to determine the extent to which the robustness against the failure of individual reactions and pairs of reactions, as quantified by the number of non - viable reactions caused upon the initial removal(s ) of a single reaction or a pair of reactions in the original networks, is bounded by structural constraints.   interestingly, we find that the two organisms exhibit cascades whose properties lie between those expected from the two considered null models, which suggest that factors other than node degrees or physical principles affect the considered features. moreover, our findings point out that, in the analyzed metabolic network, evolutionary pressure may not have lead towards minimized damage spreading, which opposes earlier findings based solely on degree preserving randomization.
the core of 350 , also known as the galactic radio source g70.31.6, was observed by the gemini north 8 m telescope with the near  infrared integral field spectrograph on the night of 20 july, 2006 ( hst ).   the object is highly obscured at short wavelengths and bright at long wavelengths. in this paper, we present @xmath0band integral  field spectroscopy data obtained using the facility adaptive optics system for the most detailed data cube yet for the core of350  which were obtained at 0.5@xmath1 resolution using the subaru 8 m telescpe and mid  infrared imager comics to obtain images and spectra near 10. the data show that the nebula is dominated by a single unresolved continuum peak in the central few arcseconds of 350.
the quantum spin hall ( qsh ) effect, which is a variant of the integer quantum hall ( iqh ) effect in two - dimensional ( 2d ) electron systems, has been experimentally realized in hgte quantum wells  @xcite and inas / gasb bilayers.   the qsh effect is characterized by an integer quantization of the quantum spin field conductivity in unit of @xmath2 in the bulk and by a pair of gapless helical edge states at the sample boundary. here   we investigate the effects of nonzero spin chern numbers on the bulk topological properties of a qsh system electrically modulated in adiabatic cycles. using the scattering matrix method, we show that the topological invariants of the edge states are directly related to the charge pumping in the edge channels through the quenching of the dipole band gap in the surface area of the qSh system. for the first time  , we find that the number of edge states can be counted through electrical measurement, and that the amount of charge pumped in the outer edge states is proportional to the total number of spin c Chern numbers in the entire system. as a consequence
galaxy clusters play an important role in precision cosmology, and their mass - observable properties are the key properties to constrain dark energy with.   however, a significant amount of uncertainty in the dark - energy constraints obtainable from large galaxy cluster surveys derives from uncertainty in scatter about the mean scaling relations obeyed by galaxy clusters bulk properties. here   we investigate the possibility of correcting for scatter in this relation using temperature - inhomogeneity in the icm, and discuss challenges that may exist in such a program.
electronic correlations are known to lead to dramatic behavior in one dimensional conductors such as carbon nanotubes, such as a zero bias anomaly in the tunneling conductance.   the purpose of this work is to reexamine the schottky relation for electron injection in the bulk of a nanotube connected to fermi liquid leads, and to show that this relation is violated when the voltage is " low ". using photo - assisted noise as a case study, we show that the fano factor corresponding to the electron charge is not followed for all parameters in this finite size geometry, but is instead a voltage dependent fano factors.
gx1 + 4 is an x - ray binary system harboring a @xmath4130s pulsar accreting mass from a red giant companion of class m5 iii ( v2116 ophiuchi ).   it is a peculiar object among the x -ray binaries not only because of its red giant companions, but also because of the high magnetic field that the neutron star ( ns ) is believed to have.    we report on the timing and spectral properties of gx 1 + 4, in particular on a strange drop in the flux during a 2000 november 1st observation carried out by the _ bepposax _ observatory.
entanglement plays a central role in quantum information theory.   it is considered a resource for quantum communication and teleportation, as well as for various computational tasks performed by observers in arbitrary relative motion. in this paper   we analyze the entanglement between two modes of a free dirac field described by relatively accelerated parties in a flat spacetime using a set of multi - qubit complementarity relations. unlike the bosonic case, where the entropy of the system degrades completely in the infinite acceleration limit, in the fermionic case   the entropy is never completely destroyed.we find that, unlike the bose - einstein case, the energy of the unruh effect depends on the number of allowed states in the system and the pauli exclusion principle, which affect the degradation of entanglements produced by the urens - rindler effect. to test this hypothesis, we consider the case that an inertial observer falls into a black hole whilst a uniformly accelerated observer barely escapes through eternal uniform acceleration. from our results  , we show that the entropy can not be completely degraded in the finite acceleration limit due to the presence of a communication horizon, and that the degeneration of ent
the triple junction ( tj ) is a line where three grain boundaries ( gbs ) meet together.   it is commonly believed that tjs greatly influence properties of nanocrystalline materials and can play a significant role during plastic deformation and diffusional creep. in this work   we use three - dimensional molecular dynamics simulations with an embedded - atom potential to compute self - diffusion coefficients along a representative tj in copper and to compare them with self-diffusion coefficients in the adjoining gbs. using the results of these simulations, we show how a tj with controlled grain misorientations can be created in the computer and how its motion can be constrained by boundary conditions. also, we introduce our methodology for diffusion calculations.
we investigate the generation of the neutrino masses and the baryon asymmetry of the universe ( bau ) in the framework of the renormalizable adjoint @xmath0 theory.   the model is based on the one - loop coloured seesaw mechanism, which is well known to be responsible for generating the lepton asymmetry in the out - of - equilibrium decays of fermion triplets responsible for the type iii seesaw, and converting it to a baryons asymmetry by sphaleron transitions in the usual baryogenesis   @xcite via leptogenesis ( lg ) scenario. here   we investigate a new range of the parameters where neutrinino masses get a sizable contribution from the one-loop coloured sawaw besides the tree level type i and iii seeaw mechanisms. since the loop term is proportional to a linear combination of type 1 and 2 seesaw yukawas, the lightest neutrinos still remain massless. with the new contribution to neutrine mass, the allowed range in the parameter space for successful lg   is enlarged but the experimental lower bound on the proton lifetime of order remains the same.
we evaluate the possibility of detecting tau neutrino signals in a variety of detectors using a stochastic evaluation of tau electromagnetic energy loss.   we find the approximate evaluation of the tau energy loss parameter @xmath0 to be reliable for both monoenergetic and power law incident neutrinos, and we compare the flux of taus following propagation through 10 km rock and 100 km rock using the sto chastic evaluation with estimates of the emerging flux of Taus using analytic approximations.
we report the construction of a photonic analog quantum simulation of the ground state of a heisenberg - interacting spin-1/2 tetramer using tunable quantum gates and single - photon manipulations.   the simulations are based on the recently proposed universal quantum computation based on coherent photon conversion, which provides an alternative avenue for achieving effective photon - photon interaction. in order to achieve this interaction,   one creates entangled singlet pairs of photons from non - linear crystals and these are used as input states for quantum simulation. by means of tunable measurement - induced two - photon interactions between the entangled photons, we show that the quantum monogamy of the excited state can be achieved by controlling the number of photons in the pair and the distance between the two photons. at the same time, the ability to prepare symmetric polarization - entangled states enables the establishment of states with bosonic and fermionic character, which are important for understanding the many - body dynamics in quantum chemistry and solid - state physics.
quantum ratchets are quantum mechanical systems that display directed motion of particles in the absence of unbalanced forces.   they are of considerable interest because classical ratcheting is the underlying mechanism for some biological motors and nanoscale devices @xcite. in a recent theoretical paper,   the authors developed a classical - like ratchet theory and proposed the existence of a one - parameter scaling law that could be used to predict the ratchet current for a wide variety of parameters.. it was also shown that an inversion of the momentum current is possible for some sets of scaling variables. in this paper, we report the experimental observation of such a ratchetCurrent inversion and the verification of the scaling law for a range of experimental parameters.
cold dark matter ( dm ) is a form of matter which is not coupled to the electromagnetic or to the strong interactions.   it is known that dm particles self - annihilate in pairs, possibly following the scheme in fig.1. this yields a continuum gamma - ray emission, which is produced by hadronization ( or final state radiation ) of the annihilation products and has a cut - off at the dm particle mass. here   we present a new method for the study of non - gravitational couplings between dm and ordinary matter, based on the measurements of the cosmic microwave background ( cmbr ) and the density profile of the halo structure of the cold dark matter. using the measurement of the cmbr, we find that the density of dm in the central part of the halos is large at the centre, and decreases with the distance from the center. as a function of the distance,   the number of gamma rays emitted per annihilation is smaller in the decay case than in the annihilation case.    the decay rate is larger than 10@xmath7 sec and the decay constant is model dependent. according to the results of our calculations, the signal - to - noise
the origin of large scale magnetic fields in stars is still one of the main unanswered questions in astrophysics.   the existence of magnetic white dwarfs has been linked to fields generated during common envelope ( ce ) binary interactions or mergers, but the origin of these fields is still a matter of debate. here   we review the current knowledge on the magnetic field structure of rotating magnetic white dwarf euvej0317-euvej317 -1 ( @xmath5855 ), which is a hot and massive redshift white dwarf with a strong magnetic field that ranges from a few kg to about 1000 mg @xcite. by combining spectroscopic and spectropolarimetric data from the sloan digital sky survey ( sdss ) and the@xcite survey, we have shown that the most extreme cases of rotating high field magnetic white Dwarfs are characterized by a complex magnetic field system with a very low - field at the very low field end of the distribution. as a function of field strength,   this system has a dipole structure that is more complex than the simple dipole observed in other types of rotating black - hole systems such as the ap and bp stars. because of
abstractaccretion provides the energy that powers radiation from the galactic center black hole, sagittarius a * ( @xcite ).   the vlt nir discovery of an infalling object onto sgr  a *, named g2, offers an especially exciting possibility for probing the nature of that accretion flow via potential interactions as the object goes through periastron @xmath7. in this paper, we present karl g. jansky very large array ( vla ), atacama large millimeter array ( alma ), and submillimeter arrays ( sma ) observations that span the time since the discovery of g2 with respect to historical variability at frequencies between 1 and 41 ghz at 1.5 and 2.0 ghz. during the period from late 2012 to mid-2014, the vla observations show no change in the flux density or activity of sgr a*@xcite, consistent with damped random walk evolution. using a combination of spectroscopic techniques, we show that the rate of accretion has not changed significantly over the same period, despite a strong precursor effect at low radio frequencies due to the potential shock forming between the incoming object and
the quantum hall effect is a well - studied model in the context of super - symmetric gauge theories and string theory.   the current understanding of the details of this model relies crucially on the composite fermion picture @xcite, which is a discrete symmetry of the partition function for the 2-dimensional ising model at one temperature to the same partition function at a different temperature. since its discovery   kramers - wannier duality has been shown to be a powerful technique for understanding the physics at and near critical points associated with second order phase transitions. here   we explore further the consequences of this infinite generalisation of kramer's duality from @xmath0 to an infinite discrete non - abelian group ( called the modular group ) for the quantum Hall effect. by combining the renormalisation group approach with modular symmetry   it is argued that the relevant duality symmetry is smaller when the splitting of the landau levels due to electron spin is small compared to the cyclotron energy and the separation of the electrons from the ginsparg energy is small.    the results are discussed in detail and the implications of this result are explored.
electronic bilayer systems have recently drawn increasing attention due to new experimental results on electronic transport @xcite and the discovery of the novel macroscopic ordering driven by quantum effects. in this paper   we tried to close this gap and have calculated the cumulant generating function ( cgf ) of a bilayer system attached to four different electrodes.   some very interesting effects were found, which can only be attributed to the non - trivial interactions between the layers. in order to perform the calculations one had to assume that the transport processes at different junctions occur in an incoherent fashion ( sequential tunneling ). despite this severe restriction the currents in both layers   are correlated due to the locality of the bound electron - hole pairs. here  we would like to drop this assumption and consider a fully coherent system. in the next section  We introduce the system and give the details of its mathematical implementation. in sections   2 and 3 we present a toy model consisting of two short hubbard chains, which are coupled with each other, so that a formation of an interchain electron -hole pair or exciton is adequately described. in section 4 we calculate the full counting statistics, compare the predictions of
the very high bulk lorentz factor and high magnetic field strengths in outflows of gamma - ray burst ( grb ) make grbs potential sources of ultra - high - energy cosmic rays ( uhec ).   recent time - resolved detections of gev photons with _   fermi_/lat from grb 080916c and grb 090510 @xcite reveal that the minimum lorentZ factor required to make the sources optically thin for such gev photon sources should be @xmath4. however, from 0.5 s to 1.0 s after the trigger time ( @x Math8 ), the short grb090510 does exhibit a very significant spectral deviation to the standard band function, which is well fitted by a smooth band function @xcites.    the extra - component counts for about 37% of the total fluence and the powerlaw dominates the standard integrated - band spectrum up to a few tens of kev and above 10 mev. here   we consider an alternative possibility, namely hadronic models, in particular photomeson cascade and proton synchrotron models @xaite, for representing the extra spectral
generalized parton distributions ( gpds ) parametrize the non - perturbative hadron structure in hard exclusive processes.   their measurement would represent a unique way to access several crucial features of the structure of the nucleon, such as the angular momentum sum rule of the proton @xcite, as well as information on the structures of the protons in position space at twist - two and twist - three.in the present paper, an approach recently proposed for the unpolarized gpds in a constituent quark model ( cqm ) scenario@xcite is extended to the helicity - dependent gpds, providing us with predictions also in the efremov - radyushkin - brodsky - lepage ( erbl ) region. by using the overlap representation of the gpds from the non relativistic model of isgur and karl ( ik )  , the same procedure has been applied to the valence quark contribution to the helical - even gpds @xmath1 and @x math2, and to the polarization - polarized gpds at twist-2 and twist-3. the results are compared with experimental data taken in deep in
abstractthe hyperfine structure of antiprotonic helium atoms is well known.   the accurate knowledge of this structure is essential for the calculation of the laser transition energies at the level of ppb accuracy needed for comparison to laser spectroscopy experiments and the extraction of the antiprotron - to - electron mass ratio. in the present work  , we investigate the microwave transitions between the hyperfine substates of @xmath26he@xmath27 in a metastable three - body system consisting of one electron in the ground state, the helium nucleus and one antiproproton. using a combination of laser and microwave spectroscopic measurements, we show that the hyper fine structure can be fully understood by measuring the transition frequencies between the super - super - hyperfine ( sshf ) states of the @x Math1 state of @xcite. here   we report on the first observation of a hyper Fine structure in antipro tonic helium with respect to its ground state in the microwave frequency range.
we show that a new set of stochastic processes can be devised that can elucidate the link between quantum mechanics and noncommutative geometry.   these processes are characterized by the presence of a bernoulli process yielding the values @xmath1 and@xmath0, exactly as expected in the volume quantization for a quantized riemannian manifold. using the euler  maruyama technique, we show their existence @xcite and we determine how spin is needed also in the non - relativistic limit. finally, we recover the dirac equation as the fokker  planck equation for a square root process.
the crab pulsar wind nebula is a very luminous source in almost all wavelengths, from radio to the very high energy ( vhe ) @xmath0-ray bands.   the overall emission seems to be steady, so that the crab nebula has been adopted as a standard candle in high energy astrophysics to calibrate observations from different instruments. in september 2010,   agile collaboration reported a flare in the vhe @x Math 0-ray band above@xmath6 mev from the direction of the crab Nebula, which lasted for about 3 days.. the observed flux during the flare period is about @x math7 times higher than the average one. since the synchrotron @x maths0-rays are produced by the highest energy electrons, these observations indicate that fluctuations at the high - energy end of the electron distribution might be responsible for the variability. in this letter   we employ a statistical approach to model the @x mathematics 0- and 1-ray variability of the nebula, and show that it is due to the statistical fluctuation of the maximum energy electrons achievable in the electron accelerators, which give rise to a " steady - state " emission
reionization of the universe took place at a redshift @xmath2.   the observed decrease in the mean transmitted flux at this redshift might simply indicate a decrease in ionizing intensity rather than a real reionization, and the observation of the ly - alpha absorption profiles of the four highest redshift quasars by sloan survey has been used to constrain the epoch of reionisation. however, one should be cautious before drawing conclusions based on such a conclusion. here   i show that combining simulations with the observational data indeed allows one to come up with a meaningful value for the redshift ofReionization.
the casimir force between uncharged metallic plates is a macroscopic manifestation of the quantum vacuum @xcite.   it is often calculated using the optical data taken from the experiments, which provides real and imaginary parts of the dielectric function within some frequency range, typically between 0.1 and 0.15  ev for the most commonly used metals, au, cu and al, corresponding to a frequency interval of 0.2 to 0.5  ev ( 1  ev=@xmath17  rad / s  rad/s ). in this paper   we present a new method for the calculation of the Casimir force using the experimental data obtained from the atomic force microscope ( afm ) measurement of the separation of uncharged metal plates with a torsion pendulum at a distance of about 2  nm. by combining the results of the recent microelectromechanical system ( mems ) experiment with the theoretical calculations, we show that the experimental precision of the force calculation is about 0.6%. however, the theoretical predictions are not sufficiently precise to be able to compare them with the experimental results. here  , we discuss the influence of material, surface, geometry and
blue straggler stars ( bsss ) were first identified in the galactic globular cluster m3 by @xcite, as a group of stars bluer and brighter than the cluster turn - off stars.   their puzzling position in the color - magnitude diagram suggested that they do not fit in the traditional scheme of stellar evolution for single stars. here  , we discuss the properties of bss candidates in the local group ( lg ) of several dwarf galaxies ( dsphs ), including the sextans dwarf, sculptor, and draco and ursa minor ; we also discuss the role of collisional binaries in the formation of these stars.
the luminosity function ( lf ) is a very important statistical characteristic of galaxy populations.   the lf provides information about galaxies and their evolution on the cosmological timescale. in this paper   we study the effect of the fading of galaxy luminosities on the observed lf for the arbitrary initial luminosity distribution and arbitrary luminosity evolution. to study the impact of the factor under consideration we introduced the initial, the current, the time - averaged, and the sample lfs. in section  we derive relations between all these lfs in general case of an arbitrary luminescence evolution. in sections  we use the popular forms of lfs, namely the schechter function and the log - normal one as the initial lfs and derive and analyze the corresponding lfs.the results show that the influence of the short - term starburst age on the measured lf can be quite significant. when the population of stars in a galaxy undergoes a starburst, the h@xmath0 emission line, far ultraviolet ( fuv ) and near ultraviolet ( nuv ) continuum luminosity decreases with time
the role of inelastic scattering in electron transport through mesoscopic systems is a topic of current theoretical and experimental interest.   recent experiments have revealed the importance of the electron - phonon interaction in transport measurements performed on certain mesoscopic devices. here   we present a method for calculating the electronic current at finite temperatures for electrons tunneling through a one - dimensional conductor in the presence of phonons based on the landauer theory of electrical conduction, assuming that the transmission probability for an electron incident from the source lead to scatter elastically through the conductor and into the drain is found by solving the single - electron quantum scattering problem. using the bon@xmath0a - trugman@xcite solution of this scattering problem   it is possible to calculate the electric current for a system consisting of a mesoscopic conductor coupled to two single - channel ideal leads that act as the electron source and drain.the electronic current is calculated by applying the pauli exclusion principle to the non - equilibrium one - electron distribution function for the system since transport is an inherently non - equilibrated phenomenon. with the help of the boltzmann equation,   the results are consistent with the model proposed by bon@
the spectrographs at the observatoire de paris ( aat ) at ctio, france, have been equipped with an automatic fibre handling system.   it has 30 arms that can point within the 20 cm, one - degree field of the prime focus of the 3.6 m eso telescope and 29 arms dedicated to the astronomical objects. in this article   we will focus on the use of the meudon eso fibre optical system ( mefos ) for the multifibre spectroscopy at the aat, which uses a prime focus triplet corrector delivering a field of one degree, the biggest for a 4 m class telescope until the 2df project will be in full operation at the bibliothème de l'automatie de la nantes ( bdnf ). using the arm system,   the spectral fibre bundles are projected on a single thomson 1024 x 1024 thick peltier cooled ccd, and are connected to a pc driving the arms by means of a computerised tomography ( ct ) control system ; the arms move radially and in rotation : each arm can cover a 15 degree triangle with its
we explore the relationship between network computation problems and matroid representations in a directed acyclic network with multiple sources, multiple sinks and each sink demanding a function of source messages.   it is known that network coding affords throughput gain over routing in such networks, and given a network and the demanded source messages at each sink, the network coding problem is to design a network code that maximizes the rate of information transfer from the source nodes to the sinks. in this paper  , we give a modified definition of matroidal networks to fit the requirements of network computations problems ; the modified definition subsumes the original definition of @xcite as a special case of network computation problem. for each input message,   the network code should be designed to maximize the frequency of target functions computation by computing the computing capacity ( computing capacity per network use at the sinks ) of the network using either network coding or routing. based on the results of previous work on network coding problems, we propose a generalization of the functional index coding problem proposed in@xcite which is to compute the sum total of the input messages of each sink in a distributed manner instead of performing the computation in a single - node manner.
the non - slip boundary condition ( nsbc ) of a piezoelectric quartz crystal microbalance ( qcm ) coupled to a torsional ultrasonic oscillator at 40  khz is used to measure the slip of a newtonian fluid at the interface between a fluid and a solid surface.   the experimental results show that the nsbc can be expected to hold on smooth hydrophilic surfaces, while finite slip lengths of order 10 - 20  nm have been measured on some hydrophobic surfaces. in the case of a shear - mode oscillating surface,   these slip lengths are typically of the order 100 - 200  nm with a range of slip lengths from 0.1 to 1.0  nm.    the long - held idea that surface roughness should inhibit slip at relatively smooth surfaces is now supported by experimental evidence.
the mixing enthalpies of ternary fcc solid solution phases in the ca - sr - yb system are investigated by first - principles calculations.   the resulting special quasirandom structures ( sqss ) are characterized in terms of their atomic arrangements to reproduce the pair and multi - site correlation functions of completely random fcc solids in a variety of compositions at @xmath5,@xmath6, @x Math7, @ xmath8, @Xmath6,@x math9, @axmath9, and @x maths10.    the generated ternaries are then applied to calculate the thermodynamic properties of four different compositions of fcc phase in an a - b - c system using calphad ( calculation of phase diagrams ) modeling approach. for each of the four compositions,   two ternular fcc sqss are obtained which reproduce the average correlation function of a completely random solution with respect to the lattice sites of the three binary alloys :  = 0.25, 0.5, and 0.75 in the substitutional @xMath4 binary alloy, [ eq
the microscopic least action principle ( lap ) is a variational principle that describes deterministic dynamics on a finite time interval for a given initial state of the medium.   it is typically available in the form @xmath0 = 0 $ ], where @x Math1 describes the wave field, @x maths2 describes the medium, and @x math3 is a known functional.. however, when the medium response is not adiabatic, the mentioned effective lap becomes inapplicable, and the problem requires a more subtle approach.    the purpose of the present paper is to find the appropriate modification of the effective lap that would incorporate dissipation under the above assumptions. by using only time - independent lagrange multipliers,   we show that the effective Lap can be modified to accommodate dissipation within it.
a phase transition from nuclear to quark matter within a neutron star ( ns ) with millisecond scale rotation period can induce a collapse that releases up to @xmath1erg in energy, which potentially relates this process to violent phenomena such as core collapse supernovae and gravitational waves.   if a significant fraction of nss undergo such a phase transition induced collapse, the energy released will contribute to cosmological backgrounds in form of photons, neutrinos, and gravitational wave ( gw ) sources. in the present paper   we estimate these backgrounds and point out that the stochastic gw background may be comparable to gw backgrounds from various other astrophysical sources. by comparing the power and statistical properties of this potential background with the ones from standard core collapsesupernovae, ns - ns coalescence, r - mode instabilities in nss with milliseconds scale rotation periods, and from magnetars  , we also find a significant constraint on the fraction of the total energy released in such phase transitions inform of mev@xmath2rays.
the quark - gluon plasma ( qgp ) is a nascent phase of matter formed in relativistic heavy - ion collisions.   the main difficulty in studying these probes lies in the determination of the initial conditions, such as, the isotropization / thermalization time vis - a - vis the initial temperature. here   we investigate the effect of pre - equilibrium momentum anisotropy on the wake induced by a high energy jet propagating through the anisotropic qgp with velocity less than the average plasmon speed ( @xmath5 ). using the htl approximation, we find that the wake in the induced charge density shows an oscillatory nature in the backward direction at large parton velocity  . this behavior is due to the influence of the parton - medium interaction which leads to the formation of mach cones and cerenkov radiation in the early post - collision phase space.
we propose a new scheme for key generation based on single photons bi - partite correlation functions.   the proposed experiment setting is similar to simplified epr protocol ( bbm92 )   @xcite, where the epr pairs are replaced with two weak coherent states prepared from a light source in the middle of alice and bob. since the output state of the light source is intrinsically entangled, the nonorthogonality of the product coherent states can not be identified by a single measurement. using this scheme,   secure key bits between two observers can be generated through sharing four bi - partsite correlation function and photon counting.    the protocol is strictly depended on equal mean photon number in the mode ( x, y ) i.e. @xmath20. here  , we discuss how this condition can restrict more than one photon in a coherent pulse in this protocol and hence to prevent the photon - number splitting attack.
criticality, with its concomitant scale invariance, power laws distributions, and extremely large correlations and response, could be a possible source of functional advantages for biological systems. in a recent work   @xcite, criticality has been shown to emerge in communities of individuals / agents trying to communicate with each other and create a collective entity.   this emerging criticality entails a large variability among individuals ; indeed, in the critical regime, small variations in parameter values are reflected in large state changes. here  , we present a variant of the model proposed in @xmathite, which maintains the same phenomenology, but is formulated in a simpler setting. by employing a mathematical formalism which allows to map a community of interacting agents into an effective fokker - planck equation, we elucidate how and why criticality comes about and investigate what are the roles of cooperation and competition among agents.
in finite dimensions, the two definitions of manifolds ( via atlases and locally ringed spaces ) are well - known to be equivalent. in infinite dimensions,   the situation is quite different.   infinite - dimensional smooth manifolds, whether locally modeled on banach spaces, frchet spaces or general locally convex spaces, have almost always been defined in terms of charts and atlased maps, because it is believed that the sheaf of scalar - valued functions does not give sufficient information to define the morphisms ( contrary to the finite - dimensional case, where defining the smooth functions valued in @xmath4 suffices to determine the corresponding morphisms valued in@xmath5 for every natural number. in this paper, we address this question by observing that the obstruction to defining infinite -dimensional manifolds as ringed space boils down to the failure of a _ scalarwise smooth _ map between open sets of locallyconvex spaces to be smooth. using a standard notion of smoothness for maps, we show that the converse is easily seen to be true in finite dimensions ( just take the linear forms of the dual to a basis based on an open subset of the underlying topological space
the dama / libra experiment is one of the most sensitive and effective experiments to investigate the presence of dark matter ( dm ) particles in the galactic halo by exploiting the model independent dm annual modulation signature ( originally suggested in ref.   @xcite ), which is very distinctive since the effect induced by dm particles must simultaneously satisfy all the following requirements : the rate must contain a component modulated according to a cosine function with one year period and a phase that peaks roughly @xmath8 2 june ; this modulation must only be found in a well - defined low energy range, where dm particle induced events can be present ; it must apply only to those events in which just one detector of many actually " fires" ( _ single - hit _ events ) ; the modulation amplitude in the region of maximal sensitivity must be @x Math8 7% for usually adopted halo distributions, but it can be larger ( even up to @x math8 30% ) in case of some possible scenarios such as e.g. those in ref..  . the experimental observable in dama experiments is the modulated component of the signal in nai(tl ) target and not the constant
the stochastic alpha, beta, rho ( sabr ) model is a key ingredient of the interest rates market   industry standard  on interest rates markets.   its popularity arose from a tractable asymptotic expansion of the implied volatility ( derived in  @xcite ), and from its ability to capture the observed volatility smile ; calibration therefore being made easier using the aforementioned expansion. in today s low interest rate and high volatility environment, this very expansion can however yield a negative density function for the price process  @xmath7 in , therefore exhibiting arbitrage. here   we study the probability mass of the sabr model for the singular part of the distribution for these regimes, that is, the probability of the forward rate process at the origin. by applying time - change techniques, we obtain tractable formulae and approximations for the exact density of the process for the uncorrelated and correlated regimes, and for the non - correlated case for which it is much harder to derive an exact density function. while standard numerical methods proved reliable when the process remains strictly positive, computing the probability masses of the Sabr model at the original origin is a more delicate issue.
scanning gate microscopy ( sgm ) has been successfully used to image local electron transport in various mesoscopic systems.   the technique is also suitable for the investigation of localization effects. in this paper  , we investigate the scanning gate experiments of the magnetic focusing devices reported in ref.@xcite using both quantum and classical transport theory. by applying the multi - terminal landauer - bttiker formalism to calculate the non - local resistances, we show that the main resistance feature ( e.g.  the spatial area of reduced resistance ) can be explained by considering geometric relations between the device boundaries, the tip position, and the circular cyclotron orbits. here, we also found that the finite width of the focusing leads can not be neglected.
non - gaussianity is a key assumption of the current cosmological model of the cosmic microwave background ( cmb ).   it is also a key underlying assumption of cmb data analysis wherein the angular power spectrum fully specifies its statistical properties, and must be tested. in this paper   we use the spherical mexican hat wavelet transform to study the distribution of temperature fluctuations in the cmb using the 1st year wmap data from the universe as a function of the @xmath4 scale. for the first time  , we find evidence for non -gaussianity / asymmetry in the data on scales of a few degrees at the level of the genus amplitudes of the northern and southern hemispheres, and a significant north - south asymmetry with a genus difference of about 2.5 orders of magnitude in the range of 3.0 to 4.0.    the results are compared with those reported in the literature, and the performance of isotropic as well as highly anisotropic multi - scale bases in distinguishing between different sources of non - Gaussianity in the Cmb has been studied.
we investigate the tadpole  improved clover   sw action and present preliminary results for the quenched spectrum at three lattice spacings.   we compare our light hadron results at @xmath4 with the conventional sw  clover approach and find no statistically significant evidence of further improvement at that @x Math3-value.    we use non - local sources to allow a more accurate extraction of ground state masses and couplings. combining our results at all three @x math3-values  , we can extract the continuum limit and assess the size of discretisation effects.. we find that dimensionless ratios of observables have small discretisations corrections., we highlight the uncertainties remaining in extracting continuum decay constants because of the reliance on perturbative matching coefficients.
red giant seismology is one of the most beautiful unexpected gifts of the space missions corot and.   it has confirmed that red giants show solar - like oscillations : as in the solar case, turbulent convection in the uppermost atmosphere excite pressure oscillations. from such study, expressed by scaling relations, we can derive global stellar properties and get keys for deciphering stellar evolution. here  , we discuss different ways to describe and measure the radial - mode oscillation pattern and explain the conditions providing the most precise measurement of the large separation. in section   , we focus on the dipole mixed - mode pattern and present a toy model used to understand the conditions under which mixed modes are observed. this models help understand the so - called depressed mixed modes observed in rgb stars, or the large variety of observable gravity - dominated mixed modes.
weak lensing of the large scale structure ( cosmic shear ) is one of the most powerful methods for constraining the cosmological model and is sensitive to both the growth of structure and to the expansion history of the universe.   the statistical power of forthcoming weak lensing data sets, which will cover thousands or tens of thousands of square degrees, makes it necessary to consider the effect of systematic errors that could previously be ignored. in this paper  , we show how to calculate the spurious shear and spurious convergence from the flat field images of the galaxy survey telescope ( ccd ) using the 2-point correlation function of the spurious convergence and its fourier transform as the primary statistics for inferring cosmology from weak gravitational lensing surveys. by adding the spurious divergence to the lensing convergence,   we show that the bias in cosmology can be reduced to a much smaller extent than that due to the shear caused by the original Cosmological shear. however, the parameter bias still remains large enough to influence the inference of cosmology when the new surveys are used to measure the shape of the background galaxies.
high mass x  ray binaries ( hmxbs ) contain a compact object ( a neutron star or a black hole ) accreting matter from a massive companion star.   they can be divided into three different sub - classes, depending on both the donor type ( ob supergiant or be star ) and the x  rays activity ( persistent or transient ) : * ( 1)*-supergiant hmxb with persistent emission ( divided into ( 1a)wind - fed and ( 1b)disk - fed accretors ), * ( 2)*-be/x  ray transients ( although there are also a few be / x ray binaries with persistent low luminosity x  Ray emission ) and, more recently, the * ( 3)*- superg Giant fast x Ray transients with fast transient emission ( sfxts ). in this review,   we summarize the current knowledge of the structure and properties of these rare binary systems, with a focus on the role of spin and orbital periods.
abstractm31 is the nearest large spiral galaxy in the local universe, and is a fundamental benchmark for studies of disk galaxy evolution.   the current study focuses on investigating the star - forming history ( sfh ) of m31 during the past few hundred myr, using the brightest resolved stars as tracers. to this end   we focus on the influence of major and minor mergers on the kinematics, spatial distribution, and age distribution of stars in the galactic halos around m31, and examine the effects of these events on the formation of globular clusters and the accretion of satellites close to m31. while the majority of the observed observations suggest that m31 has interacted with some of its companions during this time, the exact nature of these interactions is not fully understood, and it is likely that they have been limited to small - scale encounters. however, the detection of similar tidal features close to other nearby galaxies suggests that galaxy - galaxy encounters have not been rare, and may have played a key role in sculpting the current appearance of many nearby galaxies.
the evolution of the giant dipole resonance ( gdr ) line shape and its full - width at half maximum ( fwhm ) are experimentally extracted from the statistical calculations, which use the lorentzian strength function to reproduce the @xmath13-ray spectra detected from the decay of the highly - excited compound nucleus at the excitation energy.   they are often compared with the theoretical predictions, which are obtained at a given value of temperature and/or angular momentum. in the present paper  , we propose to incorporate the theoretical strength functions into the full statistical decay calculations and compare the results obtained with the experimental data. by including the nonvanishing thermal pairing gap in the landau integral,   the phonon damping model ( pdm ) is capable of correctly describing the temperature dependence of the gdr line shape at low temperature (@xmath21 2 mev ), whereas the collisional damping models ( cdm and tsfm ) fail to reproduce it at high temperature ( @x Math17 and @x maths18 ).
the vacuum polarization of a quantum field by boundaries is a well known phenomenon. in this paper   we investigate the vacuum expectation values of the energy - momentum tensor for both scalar and electromagnetic fields induced by a curved boundary in background of robertson - walker ( rw ) spacetime with negative spatial curvature.   the vacuum densities are obtained by using the well known relation between the vacuum expectations values in conformally related problems and the corresponding results for an infinite plane boundary moving with uniform acceleration through the fulling rindler vacuum.
the polarization of the light of sn 1987a was observed by polarimetry at la plata observatory from 2262 days after explosion.   several models have been proposed to explain the observed polarization in terms of scattering by the supernova atmosphere, but the degree of polarization predicted by these models is generally a decreasing function of time after explosion, as can be anticipated from the fact that the atmosphere gets progressively optically thin as the supernovae atmosphere expands. however, the observed polarized light increases sharply from 0.2% to about 1.6% at around day 100 after explosion which is difficult to reconcile with the photospheric scattering model. here   we show that dust scattering plays an important role in producing the polarized light ofsn 1987a.    the model predicts that the polarization is due to the formation of a strong initial ultraviolet ( uv ) flash of the super galaxy after the shock breakout, which is followed by the rapid evaporation of dust particles in the vicinity of the progenitor and the subsequent sublimation of the dust particles into the atmosphere. for the first time  , we find that the model is not able to reproduce the observation of the polarization caused by interstellar polarization,
the @xmath0 topological insulator, @xcite, is a two - dimensional fermionic phase of matter that is characterized by a symmetry - enriched topological invariant.   the symmetry under reversal of time acts as a protective symmetry for edge modes in ( bulk ) insulators with strong spin - orbit interactions in two and three dimensions, @xcite. we propose a new classification of the topological phases of fermion ( and boson ) systems based on the fractional quantum hall effect ( fqhe ) paradigm for a situation by which interactions select topologically ordered ground states of a very different kind than the non - degenerate ground states from the tenfold way when electron - electron interactions are strong. here   we use the terminology long - range entangled ( lre ) phase for all phases with nontrivial @x math3-dependent ground state degeneracy. using the same terminology for all other phases, i.e., those that follow the iqhe paradigm, we call them short - range entanglement ( sre ) phases. to test the validity of the new classification, we find that the number of delocalized edge channels in the bulk of
we report the first spitzer detection of a lyman break galaxy ( lbg ) at 16  with the spitzer infrared spectrograph ( irs ).   the object, j134026.44 + 634433.2 ( hereafter s - lbg-1 ), has a spectroscopic redshift of z=2.79 and is 2.5 magnitudes brighter than the most luminous lbgs in the sloan digital sky survey ( sdss ) sample.    we also show that the object is not a near - infrared ( nir ) source, but an ultra / hyperluminous infrared source ( uirg ), which is much more luminous than the ultraluminous galaxies ( ulirgs ) found in the sdss sample. to test this hypothesis, we measured the flux in 16  images of hd 46190 by comparison with template spectra from the wirc instrument on the hale 200-inch telescope, and obtained supporting near -rared data in the j- and k - bands with the wirtz instrument. using these data, we calculate the zeropoint for the origin of the uirga, and find that
we have obtained deep emission - line images of the early - type spiral galaxy ngc  1482 using the taurus tunable filter ( ttf ) on the 3.9 m anglo - australian and 4.2 m william herschel telescopes.   we find that the /h@xmath1 excitation map of this galaxy is particularly useful at distinguishing between the star - forming disk and the entrained, shock - excited wind material.
the cold dark matter ( cdm ) paradigm and its variations ( e.g., @xmath7cdm ) have enjoyed remarkable success at explaining the large scale structure of the universe.   however, it remains clear that we need more high quality, high resolution rotation curve measurements to advance towards solving the galactic scale dark matter puzzle. here   we use co interferometry to measure the inner rotation curves of several nearby dwarf galaxies with single  dish detections of ~1.5  cm2 in diameter using a millimeter wave interferometer equipped with a 2.6  mm rotational transition at 2.4  mm wavelength. by comparing the observed rotation curves with those obtained from long slit spectroscopy, we show that the density profiles of the inner regions of the galaxies are dominated by dark matter.    we find that the distributions of the radial motions of the dark matter in their inner regions are consistent with the predictions of the cdm paradigm, but do not agree with the observations.
we study the full spectrum of the transfer matrix of topologically ordered projected entangled pair states ( peps ) on the infinite plane or cylinder.   we observe one - dimensional domain walls in the spectrum as shadows of the true anyons in the two - dimensional world. by clarifying how the different anyon sectors are manifested at the virtual level, we can probe the dispersion relation of single anyon states.
we propose a quantum feedback scheme for the on - demand preparation of photon - number ( fock ) states stored in a high - quality superconducting microwave cavity and for their protection against decoherence.   the feedback loop uses three steps : a discrete quantum non - demolition ( qnd ) measurement followed by a quantum filtering process providing complete information on the field s density matrix ; a coherent field pulse injected in the cavity ; and a feedback law used to calculate the amplitude of the injection pulse. using this feedback scheme, we steer the cavity towards any target fock state and efficiently stabilize it against cavity decay.
we present the first detailed chemical analysis of 11 members of ngc  6362, an intermediate metallicity globular cluster ( gc ) with a mass of only @xmath4 @xcite.   the cluster is one of the least massive gcs where multiple populations ( mps ) have been detected and its peculiar radial distribution of its stars, with both first and second populations being completely mixed out to several half light radii, has been interpreted as the result of heavy mass - loss due to long - term dynamical evolution. here   we investigate whether it also shows other exceptional chemical features or it follows the general trends observed for standard gcs in the milky way with mps. by analysing the chemical composition of the gas from which the cluster formed, we show that the cluster exhibits a remarkable level of internal homogeneity for most of the elements studied so far, thus suggesting that the abundances of these elements in gcs can be used to reconstruct the chemical enrichment history and the age - metallic relation of their host galaxies.
we investigate the security performance of universal secure network coding based on general linear codes, which is always guaranteed over _ any _ underlying network code, even over random network code.   this paper defines the universal security performance by the following two criteria : one is called the _ universal equivocation _  ( @xmath14 ) that is the minimum uncertainty of the message under observation of @x Math1 links, guaranteed independently of the underlying networkcode. in the other is the   universal @x maths15-strong security  (@xmath15 ), where no part of the secret message is deterministically revealed even if at most @x math15 links are observed. to express these parameters in terms of code parameters,   we introduce two parameters oflinear codes, called the  relative dimension / intersection profile  ( rdip ) and the relative generalized rank weight  ( Rgrw ).. the rdips of the codes are a generalization of the minimum rank distance @xcite of a code. as a consequence, the rgrws of the networks are also generalizations of the maximum rank distance values of the corresponding codes. for the number of tapped links, both the r
optically detected magnetic resonance ( odmr ) signals of negatively charged nitrogen - vacancy ( nv@xmath0 ) color centers in diamond are studied in detail.   we show that at high microwave powers, there are two pairs of side resonances around the central resonance, which are asymmetrically offset from the central peak and separated from each other by approximately 130  mhz. for both high and low nitrogen concentrations,   the microwave - power and magnetic - field dependences of these features are studied with detail. using a combination of x - ray diffraction and density functional theory calculations, we unambiguously ascribe the origins of these resonances to hyperfine interactions between @xmath1c spins and single substitutional nitrogen atoms located in the diamond lattice.
the ads / cft correspondence provides the first string - theoretic example of the underlying generic principle of the holographic duality.   it is argued that the degenerate fermions in the ads space correspond to the composite multitrace operator constructed from product of single trace operators in the large central charge limit on the boundary, which corresponds holographically to the gravitational collapse of a massive object into a black hole at the edge of an ads space. here  , we investigate the intermediate situation where there exists amassive object before gravitational collapse into ablack hole in the Ads space and search for the dual description in the gauge theory side. using the heavy - ion collision experiments at rhic and cern s lhc  ( large hadron collider ), we show that the mass limit of the ads star corresponds to the minimum amount of injected mass required in order for the boundary gauge matter to start the deconfinement phase transition of the injected mass in the dual gauge picture.
the renormalization of the quantum mechanics formalism of quantum mechanics ( qed ) has been a major challenge in the field of relativistic quantum mechanics.   the renormalized qed, which was formulated by feynman, schwinger, and tomonaga in the late 1940 s, does not provide a well - defined hamiltonian for the calculation of the @xmath0-matrix in all perturbation orders. according to the prevailing interpretation, the creation and annihilation operators present in the ham Miltonian and lagrangian of qed correspond to _ bare _ particles having infinite masses and charges. however, the bare particles are believed to be surrounded by clouds of virtual photons and electron - positron pairs, thus forming complex objects called  dressed particles. the dressed particles are supposed to be the eigenstates of the full hamiltons of the hamiltonians of qe and qft, respectively. here   we discuss the advantages and disadvantages of the similarity - dressing transformation of the rqd model theory, which is a new approach to the renormization of qf and qed based on the concept of real dressed particles. as a result  , the
the radio frequency dressed potentials ( rf -ressed potentials ), also known as " adiabatic potentials ", are energy eigenvalues of an interaction hamiltonian for an atom interacting with an rf field in presence of a static magnetic field.   the rf-dressed potential can be made time dependent, which may be exploited for multiple purposes, such as initially for evaporative cooling of atom cloud and then for trapping in a designed geometry. in the present work,   we have used the direct simulation monte carlo ( dsmc ) technique to understand the time evolution of the atom cloud, in terms of variation in its shape and number of atoms, during the ramp of the rF - field during the transformation of the quadrupole trap into an Rf - dressed toroidal trap. by varying the r f - field parameters, the resultant rfsd potentials can be converted into a time dependent potential, which can be used for trapping atoms in a toroidal shape in a non - trivial trapping geometry like ring trap, double well and shell traps.
we study the behavior of a thin annular condensate in a mexican trap potential, where the trap potential has a quartic minus quadratic radial dependence.   we find that the system can be annular even when the trap is not rotating, and that vortices can form a multiply - quantized vortex at the center of thecondensate. to determine whether it is possible to resolve the vortex after expansion, we use a hydrodynamic model to derive analytical expressions in the limit of the gross - pitaevskii ( gp ) equation for the lowest energy excitations, or collective modes, of the condensates. using these expressions, we show that the vortex can be resolved by means of a simple two - step process, with the first step being the formation of a hole in the density around the vortex core, followed by the relaxation of the vortex into the hole through the hole itself. as the hole closes, the vortex begins to spiral towards the edge, and the second step is the closure of the hole, which is achieved by the release of the vacuum from the trapping potential.
a year ago, there were a number of pieces of evidence that pointed to a connection between gamma - ray bursts ( grbs ) and snae ( supernovae ).   the positions of grbs in galaxies, near star forming regions, were consistent with a massive star origin. in addition to the association of grb 980425 with sn 1998bw, two distant grb afterglows showed evidence for supernova in their light curves and spectra. in some cases, the afterglow evolution suggested interaction with a freely expanding stellar wind, as expected in the immediate vicinity of amassive star.    although the evidence for an association with star forming region has held up @xcite, the other topics have not provided further support. except for sn 1998 bw, the radio light curves show a smooth evolution, although the data are sparse. if grbs have massive star progenitors, they are likely to be wolf - rayet stars ; arguments in favor of this assumption have been made for the presence of dust echos in the two apparent distant supernova cases that have been observed@xcite.. however, the two best observed recent afterglowed, grb 9912
cherenkov - drift instability is a mechanism for generation of pulsar radio emission in the pulsar magnetosphere.   it was suggested by kazbegi, machabeli & melikidze ( @xcite ) as a possible mechanism for this process and later it was approved in@xcite. in those works the linear theory of cherenkov-drift instability was developed.. the necessary condition for the development of chereich - keeley instability is the presence of a beam of particles in the relativistic magnetized pair plasma with a beam particle moving along the slightly curved magnetic field lines. here   we review the history of che renkov - Drift instability and discuss the effects of the particle relativism on the generation of waves in the magnetized plasma.
we propose a general - purpose phase - based motion description learning setup that can be used in any task relying on motion.   we explore four use cases : ( i ) action recognition, ( ii ) motion prediction in static images, ( iii ) motion transfer in static image and, ( iv ) movement transfer in video. here  , we consider the eulerian approach towards motion representation learning. as a specific instance of the Eulerian model, we considers phase -based motion. for each use case, we first extract phase information from the optical flow and then input the phase information to a cnn using a pre - trained neural network. by doing so,   the learning part learns the mapping between input phase information and future phase.    we show that the learning process is fast and efficient.. we also demonstrate the application of the proposed method for action recognition and motion prediction.
we study the level density of states ( ldos ) of a single level in the vicinity of a fractional quantum hall edge on a single luttinger liquid ( ll ) wire @xcite.   we find that the ldos is sensitive to ll physics, even though its integral ( times the fermi function ) gives the level occupancy, which is universal in the above sense. for not too strong interactions the power - law behavior of the l dos is determined by ll physics alone, and is independent of the level - lead and level - bath interactions.
the search for new star clusters in the galaxy is of a great interest for investigators in the recent years.   the availability of new multiband all - sky surveys stimulates us to search them for new clusters and build a homogeneous catalog of parameters of both newly discovered and already known clusters. in paper i ( koposov et al.,   2008 ), we described the new method of an automated search for star clusters as a density peaks in huge stellar catalogs. using this method, we analyzed the distribution of stars in two micron all sky survey ( 2mass ) in the field of @xmath3 degrees towards the galactic anticenter and found 15 new open clusters. to verify the reality of detected clusters  , we developed a method, which is based on the assumption that probable cluster members lying along the same isochrone on the color - magnitude diagram ( cmd ) should also form the spatial density peak, whereas the background stars should have a flat distribution.the aims of this study are : ( 1 ) search for overdensities in the galactic plane in the range of the galactic latitude@xmath7 using 2mass data ; ( 2 ) verification of some of them as a real clusters
association rules are often used to summarize consumer trends in a transaction set or as input to a classifier   @xcite.   the problem is the very high number of rules, typically in the order of millions. that is exacerbated by the lack of thorough studies of which of the many interestingness measures for ranking association rules @xcite is most appropriate for which application domain. here  , we present, a framework to compare the outcome of different interestingness Measures applied to association rules generated in the food retail domain. using a dataset containing @xmath0 million receipts from stores in all of france, gathered over one year, 2013, we have selected the most relevant measures to rank association rules in this domain.. the results of a user study with domain experts from intermarch, one of the largest retailers in france show that the most interesting measures are the support, confidence and recall measures. according to the follow - up interview with the analysts, they also scrolled down to the bottom of the list in order to see which customer segments are not akin to buying the selected category.
the flatness of the dark matter halo of spiral galaxies can be explained by the presence of a large dark matter component in the central parts.   the halo is deformed by the gravity of the luminous disc and by the influence of the radial matter distribution of the galaxy, which is dominated by the black matter. here   we investigate the effects of the flatness and the various complex structures and substructures of the galactic plane on the shape of the Dark Matter halo and the possible dark matter annihilation signal from the central part of a galaxy. using a combination of observational and cosmological techniques, we show that the dark halos of bright spiral galaxies are not spherical, but rather have a triaxial shape with density axial ratios in the range 0.5  0.8 ( @xmath0-body simulations ). for our own galaxy,   this is consistent with the results of experiments based on atomic hydrogen spectroscopy, whereas for the sagittarius dwarf galaxy, it is more likely to be an oblate halo with a ratio of 0.2 to 0.7. at the same time, the formation of the bar structure of the disk is influenced by
there are growing evidences from various cosmic observations that support for a spatially flat and accelerating universe at the present epoch.   the acceleration is attributed to the so - called dark energy @xcite. in this paper   we make a concrete study of the possibility of probing the property of dark energy and differentiating its dynamic origin in very long baseline neutrino oscillations. using the recently released type ia supernova ( snia ) data, we show that the dynamical dark energy scalar @xmath3 coupled to the dim-5 operator can predict different spatial variation of neutrinos inside earth and consequently result in different signals in short gamma ray burst ( sbs ) and cosmic microwave background ( cmb ) experiments. on the other hand, the model with a phantom scalar coupling to the lepton violating dimension-5 operators ( lepton and higgs doublet )   predicts different signal patterns in the long baseline experiment.
we present a single semiconductor source of single photons at the rb d2 wavelength.   the emission frequency can be tuned through all the d2-hyperfine lines and the system behaves in an ideal way despite the complexity of the solid - state environment, with lifetime - limited quantum dot linewidths. this points to negligible upper level dephasing and allows us to create photons by coherent rayleigh scattering with weak, resonant excitation. we find that all our experiments ( spectral analysis, intensity autocorrelation, decay dynamics ) can be described in terms of a two - level atom with a common set of parameters.
a new method for measuring displacement at the nanometer scale in surface force apparatus, based on a capacitor included in an oscillator, is proposed.   the capacitive sensor is a low cost method which does not require the use of a lock - in amplifier, without loss in resolution or dynamic performances. when used in conjunction with an interferometric technique ( crassous ) for the purpose of calibration, this sensor can be used to perform nanorheological measurements or contact forces measurements between the surfaces.
the adsorption and absorption of b, n, al and p atoms on the surface of pristine free - standing silicene together with their substitutional doping has been investigated by density functional theory ( dft ).   the adsorbed atoms are strongly bonded to the underlyingsilicene but also penetrated into the silicon lattice. weaker bonding and immersion   is observed for the al atom.the stability of the ground state structures has also been addressed by using ab initio molecular dynamics and phonon calculations.
the possible effect of high energy cosmic ray particles on various atmospheric processes related to atmospheric chemistry and physics is debated over the last years.   we present the results of computation of ion production rate and corresponding ionization effect relative to the average due to galactic cosmic rays during one of the most interesting and major events of the previous 23 solar cycle, namely the gle 59 on bastille day of 14 july 2000. in this study,   the propagation and interaction of very high energy protons with the atmosphere are simulated with the planetocosmics code @xcite assuming a realistic atmospheric model nrlmsise2000 considering seasonal influence. for the calculation of the ion production rates and the corresponding ionsization effect, we use a full monte carlo simulation of the atmospheric cascade which is based on the contribution of cosmic rays from galactic and solar origin. as a result   it is possible to compute the ionation effect in the atmosphere during major ground level enhancements ( gles ) as superposition of the contributions of galactic and/or solar origin by combining the total number of protons produced by cosmic rays with the amount of proton s rest mass at a given time point. using the model we find that the ionization
we investigate the stability of three - fold arrangements of soap films and elastic membranes in a cylinder.   we find that when the film is stretched by pulling the anchoring wires apart, the film becomes unstable at some critical aspect ratio, and that this instability is driven by a surface - tension - driven surface tension gradient. as the length of the soap film increases, the tension increases, and the film begins to take the shape of a helical or helicoid, which then pinches off into two parts, each of which is stable for a given length of time. however, when the angle between the ends of the film changes from one end to the other, the stabilising wire is pulled away from the film, causing it to stretch outwards, and eventually collapse. these results are consistent with those of previous studies of the stretching of a catenoidal soap film between two parallel rings of radius ( @xcite ), and show that the instability is not driven by gradients in surface tension.
the hei lines in the homunculus of @xmath0 car are formed by transitions between excited levels in neutral helium.   the main properties of these lines are as follows : ( 1 ) the velocity measured at the minimum of the line profile ( maximum absorption ) relative to the system velocity along the line of sight is blueshifted at all phases, ( 2 ) the magnitude of the velocity then increases, and ( 3 ) the intensity of the blueshift increases very close to periastron passage. for some emission bands, and emission and absorption lines,   there is a consensus as to their origin, for other there has been a dispute. in the present paper   we dispute the recent suggestion made by nielsen et al. ( 2007 ) that the hei Lines originate in the primary wind.we analyze the velocity of the lines and try to constrain the orientation angle of the semimajor axis and the inclination of the orbital plane.    the orientation angles of the semi - major axis of @X-car are also discussed.
the response of vacuum to classical external fields or constraints has been studied since more than fifty years.   the most famous example is the casimir effect, which has been recently measured in laboratory with a precision of nearly @xmath0 @xcite. despite the large size of theoretical work and the experimental efforts many question remain still open. in this paper   we investigate a cylindrical shell with radius@xmath1, having a delta function as a potential profile. for a real massive scalar field with mass @x Math3, we find that the vacuum state of the quantum field is in its vacuum state at all frequencies. by renormalizing the potential using the renormalization procedure   it is possible to show that the space of the potential is continuous on the surface of the shell and the field is free in the regions where the boundary is not completely hard.the results are compared with the analogous problems of the dielectric cylinder and the magnetic flux tube.
the micro - canonical partition function of the simplified model of euclidean quantum gravity, known as simplicial gravity or dynamical triangulations, is studied using monte carlo simulations and a strong - coupling expansion ( sce ) of the partition function.   the results show that for each volume in the model there exist an ensemble of triangulation sets with a well - defined maximal number of vertices. to enumerate this ensemble we use a direct enumeration of the micro -canon partition function, i.e.  a direct summing of the sum over all _ labeled  triangulated vertices from the un - modified ensemble. by doing so   we show that the ensemble can be effectively separated into three distinct series, one of which is the ensemble of _ stacked spheres_, a particular simple class of Triangulations whose symmetry factor is given by the number of equivalent labeling of the vertices ; the other two are the series of combinatorialTriangulations with a spherical topology and with @xmath13 vertices and@xmath7 @x Math2simplices.    the latter group is characterized by a geometric phase transition separating a weak - coupling  crum
we present a general theoretical model of the non - resonant interaction between the high density excitons in a quantum well and a single - mode cavity field.   we assume that the cavity and the quantum well are ideal, and they are in an extremely low temperature circumstance. by virtue of the schwinger s representation of the angular momentum using two boson modes,   the analytical solution of the system is obtained. to study the effect of the cavity field on the radiation properties of the exciton in the quantum wells, we have studied the spontaneous radiation of the frenkel excite in a semiconductor microcavity ( smc ) under the condition of low excitation with an exactly solvable model and shown its superradiance nature. for the first time  , we show that the excited state of the electron - hole pair bound by the coulomb attraction at room temperature is not affected by the depolarization of the cavity field. however, the thermal momentum of the exctions is so small that the thermalized states of the electrons in the cavity can be directly related to the number state or the superposed state of two different number states. as a result, the stationary physical spectrum
the inverse ising problem is intensively studied in statistical physics, computational biology and computer science in the few past years.   the biological experiments or numerical simulations usually generate a large amount of experimental data, e.g., the hopfield model. to reconstruct the sparse network from the experimental data  , an additional penalty term is necessary to be added into the cost function, as studied in recovering sparse signals in the context of compressed sensing or in ising model selection. here   we present a hybrid inference method by combining the bethe approximation and the @xmath0-regularization, which is much simpler in practical implementation. to show the efficiency of this method, we apply this method to the sparse hopfield network reconstruction. using the regularization, we provide a regularized quadratic approximation to the negative log - likelihood function for the sparse networks construction by neglecting higher order correlations, which yields a new inference equation reducing further the inference error.    furthermore, the implementation is much simple by saving the computational time. ( 2 ) a scaling form for the optimal regularization parameter is found, and this scaling form is useful for choosing the suitable regularization. most importantly, the method is not limited to the
abstractthe discovery of the planet around 51 pegasi has spurred an avalanche of observations over the last 15 years, leading to a census of almost 700 confirmed planets.   these observations have also inspired a wealth of theoretical work, on both the origin and structure of such planets. despite the wealth of data and interpretation now available, it is still difficult to draw together the different elements into an overall synthesis, in large part because of the heterogeneous nature of the observations. however, in the next few years a variety of observations offer the possibility to provide new constraints, which may allow us to frame a rigorous context for planet formation and evolution.
dft is a computational quantum mechanical modeling method used to investigate the electronic structure of many - body systems.   the minimization problem of dft can be recast into the solution of an effective one - electron - type schrdinger equation, the so - called kohn - sham equation, by introducing an effective potential. due to the use fast fourier transform ( which has contributed to the success of this approach ),   large scale parallelization is hard to achieve for the plane - wave method. in this paper, we propose some parallel orbital - updating based plane -wave basis methods for solving the kohn-sham equation, which improve the scalability of parallelization. because of the independence of the source problems, these source problems can be solved in parallel essentially. for each source problem, the traditional parallel strategies ( for example, domain decomposition or parallelization in matrix - vector multiplication ) can be used to deal with it in parallel. therefore, our new methods allow for a two - level parallelization : one level of parallelisation is obtained by partitioning these source Problems into different groups of processors, and another level of concurrentization is achieved by assigning each source Problem to several processors contained in each group.
the optical photometry of bl lacertae ( pks 2200 + 420 ), the archetype of its class, was observed with the 1.56-m telescope at shanghai observatory ( shao ) during the period 1997 to 1999.   the observations were made using a liquid nitrogen cooled photometric 200 series ccd camera with @xmath3 pixels.  in addition, the light curves were reconstructed with the photometric task apphot of the iraf software package after bias, dark and flat - field corrections. for the most part, the source was observed in the fainter state at a redshift of@xmath0.  also, the emission lines were observed from the source when it was in the faintest state. among the sources,   bl Lacertae is one of the best - studied because of its large and violent variability over short time scales. here  , we present the data and analysis of the blue - shifted light curves of this object that were obtained by observing it with the same camera at shao during the periods 1997 to1999. as expected, the blue spectrum of the source showed a very rapid variation over the time scale of minutes to hours.
we propose a new definition for the fidelity amplitude of an open system.   we consider a situation where a central system coupled to two nested environments is analyzed to determine the effect of a far environment on the coherence of a central systems not interacting directly with the far environment, and thus the intermediate system or " near environment " would then be the open system we are analyzing using the qubit as a probe and as the source of the perturbation causing the fidelity decay in the absence of the far environmental perturbations.    we derive a master equation for describing the reduced echo dynamics in the near environment, which has the typical structure of master equations of kosakowski - sudarshan - lindblad form  @xcite ( henceforth referred to as lind blad equation ) and reduce to lind Blad form when the coupling to the central system becomes zero. in that case   the master equation becomes very simple, and allows to obtain a closed integral equation for the generalized fidelity amplitude. while the random matrix model used here is much simpler than the one used in ref..@xcite, its effect on the fidelity amplitudes obtained from the new integral equation is typically
the transition metal dichalcogenide ( tmd ) @xmath0-tas@xmath1 is a novel material with multiple competing ground states in it.   one of the most intriguing properties of this material is the stability of charge - density - wave ( ccdw ) state to nearly commensurate ( nccdw ) phase upon heating to 225 k. in this work, we have simulated the charge carrier doping effect on cdw by first - principles calculations in @x Math0-tsa@x math1 and found that ccdW is stable upon electric field or light induced changes in the number of electric charge carriers in the system. moreover, we found that the temperature - dependent transition from ccdws to nccds can be controlled by the influence of external electric or light field.
the in - medium properties of the vector mesons in hot and dense matter have an important role to play in the low mass dilepton production resulting from relativistic heavy ion collision experiments.   this has been a topic of great interest in the recent past, both experimentally @xcite and theoretically. in the framework of quantum hadrodynamics ( qhd ) as a description of the hot hadronic matter, it is seen that the dropping of thevector meson masses has its dominant contribution arising from the vacuum polarisation effects from the baryon sector, which is not observed in the mean field approximation. in this work, we study the medium modification of the vectors meson mass and decay widths in the hotHadronic matter within the context of qhd taking the vacuum polarization effects into account, and their subsequent effect on the dilepton spectra.
quantum electrodynamics and classical stochastic electrodynamic dynamics share their macroscopic dynamical structure.   this is because all relations for generalised phase - space quasi - distributions we obtain in this paper lack planck s constant and, ipso facto, coincide with the corresponding relations of the classical sto chastic electrophysiology  for probability distributions. here   we discuss the implications of these results, with a multitude of specifications and reservations, which are discussed at length.
the halo of a galactic x - ray source is a delayed signal induced by the scattering of the high energy photons emitted by the source by the interstellar dust grains.   the shape and strength of the halo depend on the distance to the source, the geometric distribution and the physical properties of the interstellar Dust grains. in this study  , we use the uesd method to determine the distance of a scattered photon compared with an unscattered photon from a point source using the chandra data of x -ray binary cyg x-3. for a viable point source with a light - curve @xmath12, the normalized light - curves in the haloes are calculated by fitting the time delay distribution function of the signal arrival time distribution function. given the power density spectra of the point source and the haloes at different radius, the distance between the two can be determined by fitting equation.
we investigate the relative stability of paramagnetic ( pm ), ferromagnetic ( fm ) and some possible antiferromagnetic ( afm ) phases of nacl - type fen that have been observed or suggested for other transition - metal nitrides ( tmns ).   we use local - spin - density calculations in a plane - wave and ultrasoft pseudopotential framework to evaluate the structure and density of states ( dos s ) of fen at room temperature, and to determine the equilibrium lattice constants, energies, and magnetic moments for all the considered phases. using a set of 10 to 110 special k - points ( depending on the structure ) for the self - consistent calculations, up to 280 k-points   are found for the -double and single sheet afm arrangements ( indicated as afm@xmath11}$ ] and afm @xmath12}$, respectively, as well as the -single sheet af m phase ( very common for nacl -- type transition metal oxides ), consisting of single feromagnetic sheets alternating along the / direction. by comparing the results of our calculations with experimental
gas giants form in protoplanetary disks, through core accretion followed by runaway gas accretion, or through gravitational instabilities.   the elemental compositions of gas giant gaseous envelopes or atmospheres are determined by the composition of the disk gas from which the envelope is accreted, by subsequent accretion of icy planetesimals, and by core - envelope interactions @xcite. in this letter   we show how snowlines in conjunction with pebble drift affect the c / o and c / h ratios of disk gas, and further the compositions of of gas Giant atmospheres forming through core Accretion.
the evolutionary game theory provides a general mathematical framework for the investigation of multi - agent systems used widely in economy and other social sciences where imitation is substituted for the offspring creation.   the present work introduces a collective pairwise strategy update rule providing that two randomly chosen neighbors upgrade their strategy simultaneously in order to increase their summarized payoff each coming from games with all their neighbors on the spatial system.    the results are compared with the results of two previously applied dynamical rules : the imitation of a better neighbor and the so - called myopic strategy update rules. as a consequence of the proposed strategy updaterule   it is shown that the previously mentioned  tragedy of the commons  state can be avoided even in the hard condition of prisoner s dilemma game. in the latter case   both analytical and numerical approaches indicate the existence of an ordered structure of cooperator and defector players on square lattice at sufficiently low noise level.
the remarkable field star bp psc (= sth@xmath3 202 ) has been classified as a classical t tauri star ( ctts ) on the basis of its strong h@x Math3 and forbidden line emission.   however, the discovery by zuckerman et al. in 2008 ( 2008 ; hereafter zms08 ) of an orbiting, dusty circumstellar disk and an enormous ( pc - scale ) system of highly collimated outflows ( jets ) would appear, at first glance, to provide strong support for such a classification. here  , we report the results of x - ray observatory observations of two pieces of duration 10.15 and 65.4 ks ( obsids 8900 and 10856, respectively ) from the advanced ccd imaging spectrometer ( acis ) of the _ chandra   telescope. during the observation,   the accretion of gas from the jet system was observed by using a combination of high - resolution x - rays and magnetic resonance energy shocks. among the shocks that were observed, one of the shocks was energetic enough to produce x -rays, yielding insight into the physical conditions within the jets : the shock produced by the jet
in the last two decades several experiments have provided strong evidence in favor of the neutrino oscillation hypothesis.   however a two fold question is still unanswered, does the oscillation scenario correspond to the simple 3-flavor expectation or not? which is related to the still unobserved direct appearance of one flavor to another, in particular to the highly expected @xmath0 oscillation. after a brief reminder of the physics behind we will assay to focus on the main points which brings us to the present knowledge about neutrinos mixing.. the issue of the lepton mixing is far from being fully understood and even generally described as it occurs in the quark sector. in particular the generic three questions on the reason the leptons mix themselves, the details of the way they actually mix and which are the mechanisms which underlay their mixing, arize. in 1998 a new history for neutrines began as a sort of second life with the double discovery that ( a ) they oscillate@xcite then owing a mass after 41 years from the initial idea of b. pontecorvo in 1957@excite and ( b ) they mix themselves in a peculiar way after the void result by
the x - ray spectrum of the radio - quiet neutron star 1e  1207.45209 is characterized by two broad absorption features at 0.7 and 1.4 kev.   the latter is more pronounced during the minimum and the rising part of the pulse profile, while the former is almost unvisible during the pulse peak. to obtain constraints on the equation of state of neutron stars, we have fitted a blackbody+power law model after excluding the energy bands corresponding to the features. in the overall energy range, the power law model reproduces the features better than a simple blackbody model, but only in the low - energy part of this complex spectrum.
the mechanism by which a large class of proteins folds spontaneously into a unique globular shape @xcite has remained elusive.   for instance, folding of proteins involves one or more transitions between different thermodynamic states. in this paper, we investigate the relation between helix - coil transition and folding of an artificial peptide, ala@xmath1-gly@x Math2-ala@x maths1, in a detailed representation where the interactions between all atoms are taken into account.    multicanonical simulations with large statistics are used to evaluate the free energy landscape of our peptide at different temperatures. 	 the encountered transitions are further investigated by partition zeros analysis which allows to characterize " phase transitions " in small systems.. our data suggest that the peptide in gas - phase folds in a two - step process : in a first step two @xmath0-helices are formed in what amounts to a first order transition ; afterwards these helices re - arrange themselves into a u - like structure., the second step has the characteristics of a second order transition.
the recent improved measurements of the spectrum of the electronic component and positron fraction by the fermi, hess, atic, and pamela instruments have stimulated great excitement, not only because of their importance to cosmic ray studies, but also because of the possible interpretation of some of the features from signals from the annihilation of dark matter in the galaxy.   we reproduce the observed total electronic spectrum @xmath1 and thepositron fraction @x Math2 by subtracting the secondary electrons and positrons from the spectra of the total electronic component. after this, the rest of the section is devoted to a discussion of this primary electron spectrum in terms of a set of discrete sources of cosmic rays sprinkled throughout the galaxy using the nested leaky box model @xcite.
giant molecular clouds are one of the most massive objects in galaxies.   how they manage to accumulate into such large entities with masses of @xmath7 before condensing into stars and which processes lead to their internal kinematics and density distribution is still unclear. here   we review the current knowledge on the dynamics of giant molecular clouds and discuss the role of turbulent driving in their formation and evolution.
the two hundred micron photometer ( thumper ) is a prototype camera built at cardiff university to demonstrate the viability of carrying out high - resolution broad - band imaging at 200  @xmath0 m from the ground.   it is designed to match the layout of the central pixels in the sub - millimetre common user bolometer array, scuba, when placed at the nasmyth focus of the james clerk maxwell telescope ( jcmt ) on mauna kea, hawaii. for the first time,   the thumper has been used to measure the optical depths of the sky at 200 and 1.5  thz using fourier transform spectrometer measurements of the atmosphere at the same wavelength. during the first commissioning run of the camera at 4092  m, the atmospheric transmission was measured from about 300 to 3000  ghz, corresponding to a frequency of 1.4  thZ.    the results show that the camera can be used to observe the sky with a resolution of 0.2  mm in the far - infrared waveband at this frequency.,1  hz.
the milky way stellar disk is well represented by an exponential density profile, with some evidence for a stellar disk cut - off at a radius of @xmath1  kpc towards the anticentre region @xcite, but other claims for a warped and flaring stellar disk. here   we report observations of " clump red giant " stars along 10 lines of sight in the disk of the milkyway.   the data reveal an edge to the disk at@xmath2  k pc, which is consistent with the presence of red giants in the horizontal branch ( clump giants ) located at the other side of our galaxy.
the sn2006gy supernova of the perseus - pisces cluster has been observed in a galaxy with a redshift of 5703 km / sec and a distance of 74 mega parsecs from the observer.   this distance would imply a distance closer by a factor 10 and luminosity smaller by about a factor of 100 for the supernova if its progenitor had been ejected out of the large sb ( ngc 891 ) along with some of the higher redshift material which gave rise to it. here   i discuss the evidence for the ejection of low redshift matter from the sb and the possibility that it may have come from a companion galaxy.
the star vb 10 ( a.k.a.   gl 752 b, lhs 474 ; type m8 ) was observed with the rosat high resolution imager ( hri ) during the period of 1997 october 27 - 31 for a total of 21,992 sec. within an extraction radius of @xmath4 around the optical position of vb10, 11 source photons were detected. by examining the rest of the image, we determined that the density of background photons for this observation interval ( obi ) was 0.0024 cts arcs@xmath5 and the mean count rate over the entire obi is @x Math7 cts s@x math1.    the data are consistent with the presence of a brief flare on vb Ten during the observation. in this paper  , we discuss a hypothesis to account for the stark contrast between the flare and non - flare x - ray flux values, including the possibility of a total lack of coronal plasma about vb ten.
class  i methanol masers are commonly found in regions of high - mass star - formation and have recently become the focus of high angular resolution studies aimed at searching for associations with other phenomena commonly observed in these regions.   we present a study of g309.38@xmath00.13, an especially interesting source from the spitzer space telescope s infrared array camera ( irac ) interferometric survey at 36 and 44  ghz of all class  i masers previously reported in the literature and located south of declination @xmath035. it represents the level of morphological and kinematical complexity encountered for the majority of sources observed in the survey, but it has a distinct high - velocity maser feature at 36-ghz, which was quite unexpected : it is located approximately 20 offset from the prominent hii region gum  48d at the heliocentric distance of about 3.5  kpc ( for further information on the region see *???   0.13 region ). to investigate the origin of this feature, we performed a detailed analysis of the spectral component of the maser emission in the 4.5-@x math2 m and
we revisit the deflection angle in the strong deflection limit in the reissner - nordstrm black hole spacetime and investigate the effect of the electrical charge on retrolensing light curves and the separation of a double image.   we revise a strong Deflection limit analysis investigated by bozza and mancini to obtain the deflected angle in this limit analytically without the expansion in power of an electrical charge, and we find that the newton s constant of the light speed is 1.5  j / cm2 which is the same as the original value for the light curve in the schwarzschild spacetime where the light ray is reflected by a light sphere of a star - mass black hole with the mass @xmath0 in nature. using the new formula, we calculate the refractive index of a light ray in the red - field of the dark and compact black hole solution in a following form :@xmath2 where @x Math2 is the light velocity and @x math3 is the newtons constant.    we show that the retrolenses of a black hole are not affected by the expansion of the power of the electric charge and the maximum of the
the wmap satellite has provided the clearest picture of the temperature fluctuations in the cosmic microwave background to date @xcite.   the emerging cosmological model is that the universe is spatially flat, consisting mostly of " dark energy" that behaves like a cosmology constant, about 23% dark matter, and about 4% baryons. at present, the nature of the dark matter and the dark energy are completely unknown. for now, the snap satellite@xcite has been proposed to study the nature by measuring the hubble diagram ( redshift  distance relation ) using type ia supernovae ( snia ) as standard candles, as has been done from the ground. here   we discuss the implications of these results.
the abundances of the elements more heavier than iron - group elements are mainly produced by slow neutron - capture process ( s - process ) and rapid neutron - Capture process ( r - process " @xcite.   the main s - processes occur in the low - mass and intermediate - mass agb stars, which are usually considered to be the sites of the nucleosynthesis of germanium ( ge ) in the solar system. here  , we report the results of the weak s -process calculations for a massive star with 25 m@xmath6 at solar metallicity. based on the abundance analysis of metal - poor stars,   we found that the weak r - Process abundances show excess of lighter neutron - captured elements and defficiency of heavier neutron - caught elements, which is obviously different from the patterns of the main r-process stars. because of the large overabundance of eu ( @x Math0 ), the two  main R - process stars " cs 22892 - 052 and cs 31082 - 001 arouse special attention : their abundance patterns of heavier neutrons capture elements fitted the r -Process pattern of solar system
we present a new method for computing the amplitude of a non - abelian dual model of yang - mills theory in four dimensions using a markov chain monte carlo method.   the algorithm is based on the construction of an ergodic set of moves that are used to define the two - dimensional ( hyper - cubic ) vertex amplitude of the dual model and the calculation of the appropriate expectation values of an appropriately chosen effective observable. by combining these moves with the amplitudes of @xmath0, we can perform the first metropolis algorithm simulations of dual @x math0 in four dimension.. the results show that the algorithm performs well over a range of couplings and that the sign problem is milder than expected.
the effect of random defects on the properties of solids is an important area in the study of materials.   local random defects have been thoroughly studied using sophisticated mean - field approaches like the itinerant coherent potential approximation ( icpa ) and the travelling cluster approximation ( tca ), both derived from the parent formalism : the augmented space formalism ( asf ). however, most of the work on extended defects has involved super - cell methods. here   we propose a fully real space technique, where the structure and hamiltonian of the relaxed defected lattice goes as an input into a recursive algorithm which gives us the electronic structure carrying the signatures of disorder. to illustrate the application of the proposed method, we show that the results obtained from a periodic array of sw defects can be used to study the effect of topological disorder on electronic structure of low - dimensional solids with extended defects.
the black - hole candidate @xcite has been observed to spend long periods in outburst.   the source is now in the hard - intermediate state ( hims ) and is expected to transition to the soft - intermediate states ( sims ) during the rise phase of the transition, which occurs at higher luminosities than the decline phase. here   we present a detailed analysis of the broad - band ( 3 - 200 kev ) energy spectra of the hims - sims transition during the 2002/2003 outburst of @xmath115, which led to the formation of a large - scale relativistic jet on the x - ray surface of @Xmath115. using combined data from pca, hexte and ibis, we show that the peak flux of the jet was much lower than that of the previous outburst, and that the high - energy cut - off that was present at@xmath170 kev before the transition was not detected later.. this observation is consistent with the hypothesis that the jet - line crossing was caused by a transition between the two states.
a giant x - ray outburst of ngc5905 was discovered during the ( trmper 1983 ) survey observation.   the galaxy is an hii - type spiral galaxy with no signs of seyfert activity, which makes it the only non - active galaxy that has been observed in x - rays since the last pspc observation. here   we discuss several outburst scenarios and discuss the possibility of a shock - induced outburst of ` buried'supernovae in a dense medium.
evolutionary algorithms ( eas ) have been successfully used in the areas of music and art to evolve artistic and creative outputs through an evolutionary process.   the focus of study in this paper is how ea processes can be mirrored in image transitions. using a simple ( 1 + 1 ) ea together with an asymmetric mutation operator as our baseline algorithm for evolutionary image transition  , we study the effect of running random walks for short periods of time as part of a mutation operator in a ( 1+1 ) eA.. furthermore, we consider the effect that alternating different mutation operators over time has on the evolution of the evolutionary process by comparing the results obtained from our experiments with those of previous studies.    our results show that the area of evolutionary image Transition based on different well studied random processes provides a rich source of artistic possibilities with strong potential for further exploration.
nanophotonic interfaces between atoms and dielectric micro- and nano - photonic systems are expected to facilitate strong, tunable interactions between individual atoms and photons for applications such as quantum information processing and the investigation of quantum many - body physics.   however, efficient atomic coupling to the evanescent fields of these systems requires that atoms be trapped within sub - wavelength distances of these structures. at these scales, quantum vacuum forces can overwhelm the forces associated with conventional optical dipole traps, typically resulting in a loss of trap stability at distances @xmath0 nm from dieslectric surfaces. here   we show that an atom only weakly dressed by its excited state can be trapped by properly tailoring the dispersion of the underlying structure. while a recent no - go theorem   @xcite forbids a vacuum trap for atoms in their electronic ground states, tailored nanophotomy systems can yield strong repulsive potentials for atomic excited states. using a simple model of an isotropic atom with ground and excited states  , we demonstrate that a weak external optical field can give rise to an overall trapping potential for a dressed state when the atom is in the excited state. remarkably, absent fundamental limits
we propose a reinforcement learning based slam - safe navigational planner that learns to identify robot motions that can lead to failures in slam pose estimation and avoid such motions during trajectory planning.   the method was expected to generate trajectories that have minimal failures and pose estimation errors over varying maps. through various experiments   we have proven the effectiveness of a slam - safety planner that predicts failures and executes recovery actions to continue the navigation task. in terms of learning slam -safe behaviour,   our method showed an increase in performance by about 50% as compared to supervised learning methods. in comparison with state - of - the - art planners, our method also showed about 70% improvement in efficiency for slam recovery during trajectory Planning.
we describe suzaku x - ray imaging spectrometer ( xis ) and hard x - rays detector ( hxd ) observations of the recurrent nova t crb performed on september 6, 2006.   the x-ray emission from the symbiotic star @xcite was well fit with a cooling flow model using a complex absorber consisting of components that both fully covered and partially covered the source.
the optical counterpart of x1832330 in ngc6652 has been identified by deutsch et al.   ( 1998b ; hereafter paper i ) using the wfpc2 data from 1997 september 5, 1997, and one orbit of f555w, f439w, and f218w imaging data obtained on 1995september 13. while the object, denoted star 49, exhibits a uv excess in the _ hubble space telescope _ ( _ hst _ ) data similar to other known low - mass x - ray binary ( lmxb ) optical counterparts, and similar absolute magnitude to the optical counterpart at ngc1851, the position of star 49 is discrepant at the @xmath9 level with the X - ray coordinates.. however, the region surveyed in paper i does not completely cover the _ rosat _ x - rays error circle derived in that work, and the images are not very deep.    furthermore, the location of star49 is discrepants at the@xmath 9 level with these coordinates. for these reasons  , paper i suggests that while star  49 is the best candidate for the optical precursor, its identification remains tentative.
eta carinae is a rare, eccentric massive star in the short, unstable luminous blue variable ( lbv ) phase.   the ultraviolet and optical spectra are strongly dominated by the dense wind of the primary star ( hereafter @xmath1 ), hinting that most of the luminosity of the system comes from @x Math1 . however, the observed latitudinal and azimuthal dependencies of the wind can be explained by the presence of a low - density cavity in the wind of @x math1.
the thermodynamic properties of the trapped bose - einstein condensates ( becs ) with the equal rashba and dresselhaus spin orbit coupling ( soc ) atoms at nist @xcite are investigated.   we find that the phase transition from a separate phase ( sp ) to a single minimum phase ( smp ) can be driven by the tunable temperature. in the experimentally - feasible regime,   the corresponding critical temperature is derived exactly and is independent of the trapping potential. moreover, the specific heat has a large jump at the critical temperature. this step behavior is quite different from that of the atom population, which varies smoothly when crossing the critical point. for the first time, we also investigate the effect of the effective atom interaction on the thermodynamics of the sp and the smp using a quantum field approach.
we study the interaction of a dumbbell with a flat boundary in a two - dimensional space.   we find that the number of collisions of the system with the boundary depends on the mass ratio @xmath0. if this ratio is far from 1, then the notion of adiabatic invariance can be introduced as there is sufficient time scales separation between the collision rate and the time scale separation of the collision curve. by appropriately rescaling the variables, we obtain an associated single particle billiard problem for the dumbbell which is connected by a weightless rigid rod. under certain conditions,   the adiapatic invariant type theorem can be used to estimate the maximal number of bounces of the dumb Bell with the flat boundary.
the preparation of many - particle entangled states is becoming a fundamental task in modern quantum physics.   we propose an interferometric method that uses the entanglement that emerges during the many - body dynamics between interacting spinor atoms to perform precision measurements of their interatomic interaction strength, usually parameterized by the @xmath3-wave scattering length. using this method, we can measure the atomic interaction parameters arising form two - body collisions by using similar ramsey spectroscopic ideas, but applied to interacting atoms instead of non - interacting ones.    our method is a generalization of the technique reported in ref.. @xcite, where information of the scattering properties was obtained by using the entanlement dynamics in pairs of atoms trapped in the ground state of a potential well. here   it is shown that the entenlement build up during the free evolution builds in quantum mechanical correlations between the atoms and generates a large amount of entanglements even from an initially uncorrelated sample @xcide.  also, we show that decoherence degrades the sensitivity of our method to below the heisenberg limit for initially entangled atoms and above the maximally achievable one for initially uncarried
the calibration of the rr lyrae period - ir luminosity relation ( pl@xmath0 ) has been the subject of several empirical and theoretical investigations, but there still remains some degree of uncertainty on the dependence of @xmath4 on period and metallicity.   we present an accurate analysis of the infrared photometric properties of 538 rr Lyrae variables ( 376 rrab and 162 rrc ) in 16 globular clusters ( gcs ) with @x math5<-0.9 $.    this more than doubles the number of stars used in the previous largest study of this type. 	 we calibrate the pl@Xmath0 relation by constraining its dependence on time and metal content on a strictly observational basis. using the derived relation we estimate the distance to the calibrator gcs and to a sample of field rrLyrae stars in the large magellanic cloud ( lmc ). for each cluster we identify a large number of variable stars by cross - correlating the ir catalogs obtained by two - micron all - sky survey ( 2mass ) with the database obtained by 2mass that extends to a wide area up to 15 from the cluster
in this paper, we propose a simple distributed scheduling algorithm that provides weighted fairness in ieee 802.11 @xcite wireless networks, despite the unpredictability of the802.11 mac layer and physical channels.   the algorithm is based on the concept of " virtual slot ", which means that each station counts a virtual slot when it senses a collision, a burst of transmissions ( i.e., one data - ack exchange ), or a series of data - Ack exchanges separated by sifs, or when it transmits a bursts of packets itself. for a single collision domain,   vls ( variable - length scheduling ) provides exact weighted fairness despite the unpredictable dynamics and unfairness of the 802.10mac layer and channel impairments caused by the binary exponential backoff ( beb ) algorithm@xcite. for multiple collision domains, vls provides exactly weighted fairness even though the bandwidth allocation is hard to predict.
the sloan digital sky survey ( sdss ) has discovered two new cool white dwarf stars, sdssp j133739.40 + 000142.8 ( hereafter referred to as sdss 1337 + 00 ) and lhs  3250 @xcite.   the first star is a new white dwarf with a stronger collision - induced absorption ( cia ) than the two previously known sub-4000  k wds. in addition, the rediscovery of lhs 3150, previously the wd with strongest cia, is reported. both ( re)discoveries indicate that sdss can find other similar stars.
we calculate the transition strengths and densities of the isovector ( iv ) @xmath4 strength functions in as many nuclei as possible, in all multipoles up to @x Math1, and investigate how the properties of the strength functions vary as @x math2 increases and the multipolarity changes.   we use the quasiparticle random phase approximation ( qrpa ) with skyrme density functionals and volume - type delta pairing interactions to calculate the transitions between low - lying excited states in a wide range of neutron - rich nuclei. for most of the nuclei studied here,   the low - energy peaks are found near the neutron drip line, and the transition densities are found to be strongly correlated with the strength - function peaks. at higher values of @x maths2,.e., up to ~@xmath1 mev, the high - lying excitations show a sharp increase in strength, which is not observed in the iv @xMath4 channel. for some nuclei, however, the strength peak is stronger than expected, and this is due to strong particle - particle correlations.
the online encyclopedia of integer sequences ( oeis ) lists several places where the values in sequence https://oeis.org/a000975#@xmath2 occur.   we present a method for obtaining a closed form expression for @xmath 2 using the binary representation of the fraction @x Math2 as a binary point. by rounding down and truncating this expression  , we obtain a number whose binary representation has length @x math1 and consists of alternating ones and zeros that is even or odd exactly when @x maths1 is even.
the last seven years have been a very exciting time for string theory.   a new understanding of nonperturbative features of string theory, such as d - branes, has led to exciting new developments relating string theory to physically interesting systems such as black holes and supersymmetric gauge field theories, as well as to a new understandings of the relationship between yang - mills theories and quantum theories of gravity. despite remarkable progress in these directions, however, a consistent non perturbative background - independent formulation of string Theory is still lacking.    this situation makes it impossible at this point, even in principle, to directly address cosmological questions using string theory.the purpose of this set of lectures is to give an introduction to string field theory and review some recent work which incorporates d-branes into the framework ofstring field theory. here   we briefly review the situation in string theory as a whole, and summarize the goals of this series of lectures.
electroweak baryogenesis is an attractive mechanism for explaining the asymmetry of the matter - antimatter density to entropy ratio @xmath1 in the minimal supersymmetric standard model ( mssm ).   it is based on spontaneous symmetry breaking during the phase transition from a " symmetric " phase to a " broken " phase, which occurs at a certain point in space when the second sakharov criterion is violated. as the universe cools, the probability of making a transition from symmetric to broken phase grows and a bubble of broken phase forms and expands. due to rapid gauge, yukawa and strong sphaleron interactions, the c and cp - violating source terms are translated into a net left handed weak doublet quark density which is finally converted into a baryon asymmetry by weak sphalers decays. because of its first order nature,   electroweakbaryogenesis does not occur throughout the whole universe at the same time, resulting in non - equilibrium conditions. here   we review the current state of the art in the field of electroweak Baryogenesis and propose a new framework for the theory.
the bogoliubov  de gennes ( bdg ) equation and the gap equation describe spatially inhomogeneous states in various kinds of condensed matter systems, such as superconductors, polyacetylene, and ultracold atomic fermi gases.   the equivalent equations also appear in the mean field theory of the nambu  jona - lasinio ( njl ) or the chiral gross  neveu ( gn ) model in high - energy physics. here  , we show that the self - consistent soliton solutions for the njl or the gn model need to have reflectionless potentials, using the form of jost solutions derived from the riemann - hilbert approach@xcite. this fact was proved by the functional derivative with respect to the reflection coefficient @xcite ; however, our derivation will be more comprehensive because we can see directly how the reflectance coefficient vanishes. on the other hand, we give the self -- consistent condition of the system consisting of only right - movers, which is more used in high-energy physics than the one - dimensional case of the recently determined soliton solution for the time - independent case@xcide
the atlas silicon pixel detector is a highly granular, multi - layered particle detector experiment designed to track charged particles by detecting their interactions with the detecting media at discrete points with high precision.   its design defines the ability of atlas to identify and reconstruct secondary vertices from the decay of long - lived particles containing heavy quarks, or for flavor - tagging of jets with extremely high overall track multiplicity per event. in this paper  , we describe the design and operation of the atlas pixel detector, which is comprised of a silicon sensor, front - end electronics, and flex - hybrids with integrated control circuits that are functionally identical at the sensor and at the integrated circuit levels. as the innermost tracking sub - system, the pixel detector provides excellent impact parameter resolution and low occupancy per readout channel, with multiple interactions being common at full lhc design luminosity of @xmath1 .
x - rays from cool stars are a manifestation of magnetic fields generated by the internal dynamos.   this by now classical view has not changed despite the discovery of new x - ray phenomenology and the development of new theoretical concepts with which to explain the production of x - rays around stars ( e.g., accretion, outflows, fluorescence, etc. ). however, with increasing detector sensitivities and the advent of high - resolution spectroscopy, " stellar environmental issues " have become of central interest in the area of pre - main sequence stars. the interplay between accretion disks and stellar magnetic fields leads to disk instabilities, ionization and heating of circumstellar material, chemical reactions in cool molecular gas, accretions flows from the disk to the star, outflow, and jets, in all of which x -rays either play a key role or at least provide important diagnostic access.
the bandwidth coloring problem ( bcp ) is a generalization of the classical vertex coloring problem, which results in the case where @xmath12 for all distinct pairs are assigned to each vertex.   the bandwidth multicoloring problems ( bmcp ) are also generalizations of bcp, where each vertex is associated with a positive integer and each edge has an edge weight. here  , we propose a heuristic algorithm for solving bcp and its generalizations, called path relinking ( pr ), which combines a local search with constraint propagation for solving the problem. using a combination of iterated tabu search and path relinkings,   we find that pr is effective for solving both the bandwidth coloringproblem and the bandwidthmulticoloring problem.. the pr algorithm is more efficient than the current state - of - the - art heuristic approaches for solving these problems.
graphene is the new star of condensed matter physics.   it has been shown to produce from few layers of graphite ( flg ) to one unique graphene layer ( @xcite ) on a single silicon - terminated substrate ( sic ). in this work   we show that the substrate has a strong effect on the first two carbon layers of graphene and that the interface c buffer layer is strongly distorted so that it can not be seen as a graphene layer but should instead be considered as the very beginnings of graphene. using ab initio calculations supported by scanning tunneling microscopy ( stm )  , we demonstrate that the surface morphology of the substrate affects the electronic structure of the interfacial graphene layer. for the si - terminated face,   the interaction between the substrate and the graphene is stronger than for the c - terminated side.. the interface geometry of the first c layer is studied using ultra soft pseudopotentials ( uspp ) and the results are compared with those of ab initial calculations performed with the density functionnal theory vasp based on the perdew and wang formulation of the general gradient approximation. moreover, ripples are shown to be generated in the otherwise
we use flux data from a variety of catalogs to construct models of source spectra as a function of frequency.   we analyze simulated skymaps at frequencies from 10 to 300 ghz to determine the expected contribution of radio galaxies to foreground confusion of cosmic microwave background explorer ( cobe ) temperature anisotropy. using our current catalog of 2207 discrete radio sources, we find that the contribution of extragalactic foreground sources to the overall level of foreground confusion is negligible at frequencies below 200 ghz, but increases with the inverse of the beam area of the cobe dmr experiment. in the case of frequencies above 100 ghz and high - frequency ( @xmath6 ghz ),   the contributions of galaxy clusters are much larger than expected due to the sunyaev - zeldovich effect from galaxy clusters and the redshift of the universe.
rna is an important biopolymer critical to all living systems and may be the crucial entity in prebiotic evolution.   understanding the encoding of structure from the primary sequence has been an outstanding problem of theoretical biophysics. here  , we study the problem of rna folding by studying the statistics of secondary structures formed by the ensemble of _ long _   random _ rna sequences ( of at least a few thousand bases in length in practice ). using a self - contained introduction of the random rna problem to statistical physicists as a novel problem of disordered systems,   we describe several approaches we have tried to characterize this system with respect to the thermodynamic properties of the  molten phase ", which is the simplest possible phase of the system assuming sequence disorder is not relevant. for each of these approaches, we show that the solution of the two - replica problem is relegated to the appendices of the monovalent ionic solution when the system is in the molten phase, and support this conclusion by computing the exact partition function of the secondary structures from the ground state structure.
we study the effect of the non - linear interaction between a single two - level atom and a single mode of a one - sided cavity on the shape of one- and two - photon wavefunctions using gaussian input pulses of different pulse lengths.   we analyze the interaction processes for a long pulse length of @xmath1 in terms of pulse amplitude and pulse delay time. from these results  , we can estimate that a maximal non -linear effect should be obtained for a pulse length equal to the dipole relaxation time of the atom. in this paper, we therefore analyze the corresponding interaction process for a short pulse length with respect to the characteristic time scale defining the response of theone - dimensional atom to a one- or 2- photon input pulse.. the results of the analysis are summarized and discussed in section .
the mass of first - generation stars in primeval galaxies at redshift @xmath11 - 30 is controversial.   the initial mass function of population iii stars may be bimodal with peaks of ~16  ~17 and ~18 for low - density and ~20  ~25 for high - density gas clouds, respectively. since the effective hd cooling makes the high mass peak small to ~24, very massive stars with mass values of ~25 are formed preferentially. here  , we show that the population iii star mass peaked at ~25 when the initial density and the initial fraction of molecular hydrogen are similar to those of the present - day galaxies.. the mass of population 3 stars is higher than that of population 4 stars because of the large c and n enhancements observed in the extremely metal - poor stars in our galaxy.
the generation of relativistic electrons is the key to the generation of x - ray and secondary particle sources.   the interaction between the plasma electrons and the main laser pulse is the primary channel for the energy transfer from the laser pulse, providing the basis for a wide range of phenomena and applications. in this paper  , we examine the role played by transverse and longitudinal quasi - static electric fields present in a plasma channel in enhancing the electron energy gain from the direct laser acceleration regime. as a consequence, we show that the super - luminosity of the laser field that is induced by the channel can limit the electron injection into the laser beam and the amount of electron acceleration that can be achieved using the laser pulses.
quantum cryptography is a new technique for exchanging secret information through a communication channel in a secure way.   it relies on the safety of the key, which is a string of bits that is combined with a random string ofbits of equal length called the key and shared by both legitimate users. to achieve this,   the key must be secret and shared only by the two users, and the message must be totally unintelligible to a potential eavesdropper. at present, there are three different quantum cryptographic systems based on the transmission of single photons randomly polarized along four directions : the first one uses weak pulses of coherent light, the second one uses only two non - orthogonal quantum states ; and the third one uses pairs of epr correlated photons. in this work  , we compare the security of these systems, and show that the latter system is more secure than the other two.
symmetry is one of the basic principles that penetrate all of physics : from classical to quantum physics, from statistical or condensed matter physics to particle physics, and from relativity to gauge field theory.   since quantum mechanics and field theory are, in some respects, modeled and devised after classical mechanics, we see that not a few methods and notions, including symmetry, in these two fields resemble those in classical mechanics. for this reason, we may interpret that although " the physical world is quantum mechanical'',@xcite the quantum feature are somewhat transmitted to the classical world ; and through the latter we may try to grasp the former. here   we review the history of coherent states evolving from a generic fiducial vector ( fv ) as the mathematical tools, or a sort of new language, for quantum physics.
the influence of spin orbit coupling on the spin wave spectrum of ultrathin films adsorbed on w(110 ) metal substrates is studied.   the effect of the dzyaloshinskii moriya ( dm ) interaction on the dispersion relation of spin waves in the fe monolayer and bilayer on w is investigated by means of theoretical studies of the spin orbit effects on spin waves and also on the dynamic susceptibility of the substrate upon which the film is grown. when the magnetization is in plane, the dm interaction introduces a term linear in wave vector in the dispersive relation of Spin Wave Dispersion relations, which is found to be in the range of @xmath0 cm / sec for the ferromagnet with the mn monolayers on w.@xcite as well as for the bilayers onw(110).we find that this term is due to the existence of a strong spin orbit interaction between the 3d and the 5d orbitals of the magnetic moments in the films, which can be explained by the presence of a very large w spin orbit coupled to the 2d orbital of the transition elements.    we find that the
soft x - ray transients ( sxts ) are compact binary systems in which a low - mass secondary transfers mass via roche - lobe overflow onto a black hole ( bh ) or neutron star ( ns ) primary.   they spend most of their lifetimes in a low luminosity quiescent state, but occasionally undergo dramatic outbursts during which both the optical and X - ray emission increase by several orders of magnitude. in this paper  , we show that there is indeed a significant difference in the observed quiescence luminosities of the two classes of objects, in contrast to the claim of chen et al. ( 1998 ) that this difference is a confirmation of the presence of an event horizon in bh sxps. using a combination of spectroscopic and theoretical techniques, we find that the observed q2-luminosities are significantly lower than those predicted by the standard disk instability model for quyingcent disks. on the basis of these observations,   we propose a new model for the accretion of matter into bh Sxts, which assumes that the bulk of the viscously dissipated energy is stored in the gas and advected with the flow
random walks on the t - fractal ( t - graph ) have been extensively studied by many groups, revealing some scaling relations and dominating behavior. in this paper, using the connection between the random walks and electrical networks  , we investigate random walks of the t-graph.   we derive analytically an exact formula for the mean first - passage time ( mfpt ) averaged all pairs of nodes, which characterizes the efficiency of random walks performed on the T - graph with a perfect trap uniformly located at all nodes. to test the validity of our method, we show that the location of the trap has no qualitative effect on the scaling for m fpt. however, when the trap is fixed at a given node, the scaling of mfps is affected by the number of traps, and the survival probability of the walker returning to the same node is higher than that of a walker originating at a different node. as a result,   the results suggest that the existence of a single trap may not be sufficient to explain the observed scaling relations.
we present the first detailed study of periodic orbits in triaxial models with weak central densities, or cusps, characteristic of bright elliptical galaxies.   we show that the @xmath2- ( long- ) axis orbit, which generates the boxlike orbits in stckel potentials, is the most strongly affected orbital structure in these models. using a nonparametric deprojection algorithm, we derive expressions for the gravitational potential, force and force gradients for the closed " boxlets", the low - order resonant orbits that act as parents of the box like orbits in non - integrable Triaxial potentials corresponding to mass models with divergent central density profiles. by comparing the results of our calculations with those of previous work on the power - law nature of the central brightness profiles of early - type galaxies, we find that the observed central surface brightness profile of the faintest elliptical galaxy with a weak central density,@xmath16, is consistent with the generalization of dehnen s law, with a central density that increases more rapidly than @x Mathieu s law.see research article http://www.biomedcentral.com/1471-700
the cellular signaling machinery @xcite acts as a decision - making device that maps the large number of inputs signals to a reduced set of behaviors characterized by specific outputs.   these complex signal transduction processes must work reliably even in the presence of a substantial amount of environmental noise, and are therefore bound to be affected by non - saturating levels of external signals. here  , we review the recent advances in our understanding of the constructive effects of noise on the behavior of biological systems, and discuss the role of noise in the regulation of signaling pathways.
the relation between charge equilibration and the zero sound propagation in femto - scale quantum liquids is investigated.   the theory of sound propagation inside gases is derived from the classic theory of motion and equilibrium probability density calculations, and then simplified to the level of the fermionic property of heavy ions colliding at the energy of a few mev per nucleon. based on the results of experiments of low - energy heavy - ion collisions, it is shown that the existence of charge equilibrium in the final products of these collisions is not limited to the isovector giant dipole resonance, but can also be explained by the fact that the reaction dynamics and the resulting products can be drastically different depending on the impact parameter, the mass of colliding ions, and so on.
the magnetocentrifugal mechanism is the leading candidate for producing the jets and winds observed around young stellar objects.   the quantitative properties of the jet expected from this mechanism are poorly determined however, even though the mhd equations that govern the wind structure and jet formation are well known. to obtain a converged solution, one needs to have a good initial guess of the fast surface position, which is generally difficult to obtain. here   we present a time - dependent approach to finding steady - state disk - wind solutions using the zeus magnetic field theory ( mhd ) simulation code. in the case of a cold wind that is driven off all of the ( equatorial ) disk surface, the solution is obtained by injecting a light fluid with little mass flux into the wind at a speed fast enough to escape from the potential well along those field lines that fail to operate magnetocentrifugally. when the wind is injected into the outermost region of the keplerian disk, the field lines become toroidal, and the poloidal flow speed matches the fast magnetosonic speed. as a result, the inner part of the wind can be solved first by relaxation, and then by the method of characteristics.
the ads / cft correspondence@xcite, more generally the gauge - gravity duality, has emerged as a powerful tool to address aspects of strongly coupled physics.   it is particularly useful for systems driven out - of - equilibrium, where the governing principles are much less understood. in this article  , we explore an emerging principle for a non - equilibrium steady - state ( ness ) situation within a probe sector which is kept in contact with a large background at some given temperature : the existence of an effective temperature, denoted by @xmath3, with respect to which all modes in the probe sector experience a purely thermal behaviour. for a conformal system,   this effective temperature is always larger than the background temperature. for gapped systems, or systems with a running coupling constant, there may be additional dependences on the beta function of the gauge coupling or other dimensionful parameters in the system. for critical systems, however, this effect depends only on three ingredients : ( i ) dimensionality, ( ii ) the global symmetry group and ( iii ) how ness is induced. for the ness, these three factors are not necessary.
the metallicity of and Andromeda s red giant branch ( rgb ) stars has been studied using the panchromatic hubble and Andromeda treasury ( phat ; *??? * ) photometry.   the rgb stars are resolved at a wide range of radii from 0.1 to 1.0  kpc using a distance modulus of 24.45@xmath60.05 mag or 776 @xmath618 kpc.    the results show that the rgb metallicities are highly correlated with the age of the galaxy, with the inner regions forming earliest ( e.g. *????   * ; *????* ; *?, the outer regions form late in the galaxy s life cycle ( i.e.   < 1.5  years ). for each year of life history, the rgb star mass decreases by ~2.5% ( p<0.001 ). erythrocytes are the main source of the reduction in the rgb metallivity, with ~3% of the decrease occurring in the early stages of life cycle. within the binary system,   there is a strong correlation between the radial effective radius and the
@xcite was the first paper to show that the giant planets of the solar system did not have the current orbits when they were still embedded in a disk of gas.   the so - called nice model suggested that the planets formed in a compact configuration with jupiter, saturn, uranus, and neptune around 5.45 au, sittingurn slightly interior to the 2:1 mean motion resonance ( mmr ) with j Jupiter at @xmath05.4 au, while uranus and Neptune were scattered onto orbits with relatively large eccentricities and semimajor axes, which crossed the original trans - neptunian disk. following a phase of dynamical friction caused by their interaction with the remaining planetesimal disk, the orbits of uranus or neptuni damped in eccentricity and inclination. a residual planetesmal - driven migration placed the planets on orbits fairly similar to the current ones. here   we investigate whether this initial multi - resonant configuration could still lead to a _ late  giant planet instability, in order to explain the putative late heavy bombardment of the terrestrial planets @xcire and @crispice, which occurred after hundreds of my of
the recent appearance of tags in large online datasets represents a significant innovation in categorisation @xcite.   tags allow multiple categories for each item, and tagging can be done in a bottom - up approach, in a parallel manner, by several users simultaneously. here   we analyse the hierarchies obtained for the scientific keywords from the web of science by applying a recent generalisation of the method given in ref.@xcite presented in @xaite. to obtain a tag hierarchy, we use a directed acyclic graph of the tags, where links are directed from more general concepts to more special ones. as a first step  , we rank first the tags according to the eigenvector centrality of the tag - coappearence graph, and then we define which tag should be placed higher in the hierarchy and which lower. for each tag an appropriate parent is chosen based on the z - score between the tags. at the end of the second step, we construct two alternative hierarchies, one for the author given tags and the other for the repository given tags, resulting in two alternative 3-level classification of categories. these are compared to each other and also to the 3- level classification
we propose a one - dimensional model for the potential and charge distribution across the plasma - wall interface between a collisionless plasma sheath and a dielectric surface which is assumed to be a perfect absorber, that is, the wall potential balances at a certain distance from the crystallographic interface the electron and the ion influx from the plasma.   the model assumes that the plasma wall is an electron surface layer of a certain extent, which is trapped by and in thermal equilibrium with the wall. using a graded interface model, we show that the electrostatic interaction between the plasma and the dielectic surface leads to the formation of a quasi - stationary wall charge ( electron adsorbate ) which is responsible for the reduction of the potential just outside the wall as well as the re - distribution of the free - standing, uncharged surface into polarization - induced external surface states ( image states ) on the surface of the plasma.the theoretical results are compared with experimental data for aqueous plasma sheaths and solid - state based micro - discharges where the wall charge is considered as a two - dimensional surface plasma coupled to the bulk plasma via electron - ion wall recombination.
concavity is a property of thermodynamical functions that can be deduced from experimental data at zero temperature.   this is obtained by an analysis of the table of second differences between binding energies, then by a removal of the pairing energy, and finally by an ad hoc parabolic term added to the nuclear energies, if necessary. in this paper, we show how elementary, invertible transformations of data can generate truly concave patterns for a sequence of isotopic ground - state binding energies with respect to @xmath6 and@xmath7. using a generalization of the zero temperature analysis to finite temperatures, we discuss properties of the grand potential, @x math20, which can be inferred from the experimental data after their tuning. other thermodynamic functions are also considered, and their concavity parameters are tested.. bounds are found, and an error bar for predictions is estimated.
in order to obtain high spectral efficiency, interference management is one of the most important issues in wireless communication systems. for the @xmath0-user interference channel,   the degree of freedom ( dof ) was shown to be upper bounded by @x Math2 in @xcite.   this upper bound can be achieved by the interference alignment ( ia ) scheme that all interfering signals from other transmitters are aligned in the same dimension to independently decode the desired signals at the receivers. in this paper, we assume two delayed feedback scenarios : ( i ) no channel state information at transmitter ( csit ) and ( ii ) delayed output feedback without csit. with the same assumptions of delayed feedback, we devise effective interference management strategies in the@xmath8 user interference channel for these two scenarios. using the ergodic ia scheme, we show that the proposed schemes achieve higher dof than the retrospective ia @xaite in the @Xmxmsi interference channel.
resonant inelastic x - ray scattering ( rixs ) is a technique that matures rapidly due to the recent increase in brilliance of the new generation synchrotron x -ray sources, where high flux photon beams with energies that are tunable to resonant edges are now becoming widely available  @xcite.   the probability for x - rays to be scattered from a solid state system can be enhanced by orders of magnitude when the energy of the incoming photons is in the vicinity of an electronic eigenmode a resonant edge of the system. at this resonant energy a@xmath1 electron from the inner atomic core is excited into an empty @xmath2 state, and the excitation energy is determined from the difference in energy and momentum between incoming and outgoing photons. since the excitations are caused by the core - hole, we refer to this scattering mechanism as indirect resonant inelsas ( rices ). in this paper   we present a detailed derivation and various generalizations of the dynamical correlation function that is used to derive the effective scattering cross section for indirect rix s. for local core -hole potentials and ultrashort lifetimes, the dynam
we introduce a simple growing network model with copying ( gnc ) that naturally generates sparse networks in which the average node degree diverges logarithmically with system size.   we dub these log - networks. to motivate the copying mechanism, we Recall the growing network with redirection ( gnr ) model, which is a simplification of a previous model @xcite, which was proposed to mimic the copying of links in the world - wide web. in this model,   each new node links to a randomly - chosen target node and also to its ancestor nodes subject to a constraint on the maximum number of links created. in the following sections, we analyze a gnc model with no global bound on the number of linked emanating from a new node. using the master equation approach  , we derive basic geometric properties of the network and compare them with data from physical review citations.
the quantization of polarized gravitational cylindrical waves in general relativity has received a lot of attention in recent years.   this is partly due to the fact that this system provides a tractable, yet non - trivial, reduction of full general relativity and hence is an ideal framework to explore several issues involved in the quantification of gravity. here   we study the smearing of light cones due to quantum gravity effects within the framework of linearly polarized gravitational wave quantization using the free hamiltonian for a 2 + 1 dimensional, axially symmetric, massless scalar field evolving in an auxiliary minkowski background @xcite as a function of the free part of an interacting model. by studying the commutators of the field operators at different spacetime points  , we show that it is possible to give exact expressions for this commutator both for the evolution provided by the free and the full physical hamiltonians. these expressions are used to study in a quantitative way the Smearing of the light cones as a result of quantum gravity effect on the three - dimensional gravitational constant and explore some physical issues, in particular the appearance of singularities as a consequence of having a ham Miltonian bounded from above
we investigate the effect of a logarithmic transform of the density field on the relation between the density and displacement fields.   we do this by measuring the divergence of the displacement field, which in linear theory is proportional to the negative density contrast, using both eulerian and lagrangian techniques in a cosmological @xmath0-body simulation. with the exception of the redshift and smoothing scale,   the results are consistent with the results of previous work that have used the linear zeldovich approximation of the Lagrangian displacement as the model for the displacement force.    we compare the linear and logarathmic approaches and evaluate their dependence on redshift or smoothing scales, both of which affect the applicability of linear theory.
moulin s theorem is one of the most famous impossibility theorems in social choice theory.   it states that voting rules that satisfy the axioms of condorcet - consistency and participation are incompatible whenever there are at least 4 alternatives and 25 voters. here  , we show that the bound on the number of alternatives is tight by showing that the maximin voting rule ( with lexicographic tie - breaking ) satisfies the desired properties when there are only 3 alternatives. to achieve this, we encode these problems as formulas in propositional logic and then use sat solvers to decide their satisfiability and extract minimal unsatisfiable sets ( muses ) in the case of unsatisfiability. using this approach, we obtain an elegant human - readable proof of moulins theorem that requires only 12 voters.
coexistence between the spin - singlet superconducting order parameters and spin - triplet one is the essential feature of noncentrosymmetric superconductors ( ncs)@xcite.   the presence of surface bound states at the zero energy is known as the low - temperature anomaly of josephson current. in this paper, we theoretically calculate the jose phson current between two ncs s  @xcite based on a current formula   in terms of the andreev reflection coefficients of junctions. for the first time  , we assume a order parameter which is a mixture of the spin -- singlet @xmath5-wave and the spin--triplet helical @x Math2-wave symmetries.    the results show that the josedepole current between the two nc s is larger for the order parameter with the spinsinglet component @x math2 than for the spin singlet component #@xmath0.
the b2v star hr5907 is a rapidly rotating, non - degenerate, magnetic massive star with a strong magnetic field.   we have obtained high - resolution ( @xmath1 ) observations of the star using the espadons spectropolarimeter at the canada - france - hawaii telescope and the eso - vlt fors polarimetric observatory. using hipparcos photometry, we find a single - wave period of @x Math3d, which differs from the double - wave photometric light curve of hr7355 or @x math0  ori e, likely indicating a different geometry of the magnetic field in these stars. from our longitudinal magnetic field measurements, we confirm this period, which we take to be the rotational period of this star. by using fits to the longitudinal field curve  , we estimate that hr 5907 hosts a mainly dipole magnetic field, with a strength at its pole of@xmath10 kg, and a magnetic axis nearly aligned with the rotation axis. based on these estimates, we propose that hr59 07 is a co - rotating, rotating, magnetically confined cloud of stellar wind plasma.
we report the first clear example of a cluster bow shock front in a galaxy cluster.   the shock front was observed by acis - i at the focal plane temperature of @xmath9c for a useful exposure of 24.3 ks. to derive the gas temperature for a given region of the cluster image, we modeled the telescope and detector response as described in mv ( markevitch, sarazin, & vikhlinin, 2001 ). from this model,   we derive the temperature of the merged cluster at 17.6 ks. the results are compared with data from the most luminous synchrotron radio halo ( lhba ), a hot region in front of the a665 core.
a new method for examining gravitational lensing effects has been proposed by holz & wald ( hw ), one which has the virtue of lending itself easily to numerical calculations. in that work   it is shown that given a large and deep enough sample of standard candle supernovae, one may in principle distinguish between different matter distributions in the galactic halos responsible for the lensing.   the purpose of this paper is to generalize the method of hw in a number of ways and to investigate some issues related to the different lensing signatures in the luminosity distribution of supernova caused by different mass distributions of the intervening lens population.
the contribution of the interference between the photon and the z boson exchange amplitudes at centre  of  mass energies near the z resonance is fixed to the standard model expectation.   we use an s  matrix@xcite approach to determine the contributions of @xmath0/z interference and z Boson exchange to the measured cross sections and forward  backward asymmetries for the fermion  pair production reaction, @x Math1, at centre - of - mass energies above the z resonances.    the results are sensitive to the uncertainties on the theoretical predictions of the x   bhabha scattering and the strong coupling constant.  in particular, the calculations of the qed radiative corrections to the cross sections from the measured data are more sensitive to these uncertainties than the predictions.
the fulde - ferrell - larkin - ovchinnikov ( fflo ) superconducting / superfluid phase is a condensate of cooper pairs with finite center of mass momentum and the spatially modulated order parameter  @xcite.   the experimental study of the fflo phase in the frame of mean - field theory is problematic since the pair fluctuations become significant with the reduced dimensionality and true long - range order in 1d is completely destroyed by the mermin - wagner theorem but has only power - law correlations in the thermodynamic limit. in order to overcome these technical difficulties peculiar to pure 1d systems, the two - dimensional array of 1d atomic " tubes "   has been proposed as a model of quasi-1d fermi gas, where atoms are allowed to move freely in one direction and tightly confined in the transverse motion. in this model, the weakly coupled 1d system the atomic motion is gas - like in the axial direction but the weak coupling in thetransverse lattice plane stabilizes the long - ranged superfluid order.. the stabilization of the long ranges order allows the use of mean field theory while the anisotropy
massive multiple - input multiple - output ( mimo ) is considered as one of the most promising technologies for next generation wireless communication systems, since it can provide very high spectral and energy efficiencies.   however, a comprehensive scaling law analysis for multi - cell multi - user tdd massive mimo downlink systems with channel spatial correlation, channel state information ( csi ) error, and pilot contamination is still missing in existing works. in this work, by drawing lessons from the analyzing method and the mean square convergence definition in @xcite, we provide a comprehensive scale - up analysis for these systems with a focus on the applicability of the derived asymptotic scaling law in practical systems with large but finite antenna numbers. to validate the analytical results, extensive simulations are also conducted to evaluate the effect and joint interaction of extensive network parameters, i.e., the channel training energy, the transmission power, and the pilot contamination elimination effect. using the obtained results,   a general performance scaling law is derived based on which a general capacity lower bound on the system sum - rate is derived.
@xcite quantum dots ( qd s ) are characterized by a strongly distorted single - electron transport spectrum where avoided crossings and lifted degeneracies in the energy spectrum are clearly observable.   we reproduce the spectra with an appropriate model potential, showing that the unexpected effects in the spectrum result from a negatively charged coulombic impurity located near the qd. using the spin - density - functional theory ( sdft )  , we show that the many - electron properties studied by the sdft reflect the strong distortion of the circular symmetry of the system caused by the presence of the impurity at the center of the quantum dot.the results are compared with the results of diffusion quantum monte carlo calculations on qds distorted by randomly distributed gaussian scatterers and the behavior in the high magnetic field limit.
the cosmic microwave background ( cmb ) is a rich source of information about the ionization history of the intergalactic medium ( igm ).   reionization is one of the most famous examples of this process, and it is now well established that the igm is highly ionized at redshift @xmath5, the redshift of the ly@xmath6 emission lines, implying @x Math7. in the present review,   we summarize our current knowledge of reionizing sources, describe the possible connections to the cmb, and assess what we can hope to learn about the high  redshift igm from forthcoming observations of the cMB anisotropies.
scalar hair is a strong interpretation of the no hair conjecture.   it demands the non existence of any information other than mass, charge and angular momentum of a black hole. in this paper,   a nontrivial black hole solution of a massive but self interacting scalar field showing no divergence at the horizon and asymptotically falling to the vacuum value is reported.. the proposed metric shows trace of scalar charge.
we construct a quantum theory of free fermion fields based on the deformed heisenberg algebra.   we respect the supersymmetry in this context as a guiding principle. because of existence of natural cutoffs as minimal length and maximal momentum, the superconformal mechanics is deformed. from the fermionic part of the system, we propose an action of ferm ion field based on generalized uncertainty principle ( gup ) in a spacetime with arbitrary number of dimensions. to test the suitability of the proposed action, we compute some scattering amplitudes such as the pair annihilation amplitude.
the kinetics of nucleated linear self - assembly of protein monomers into polydisperse polymer - like objects, i.e., the time evolution of the polymer length distribution, can take place via a host of different molecular pathways.   these pathways include end evaporation and addition, scission and recombination, secondaryucleation, two - stage nucleation, and so on. to study the stochastic nature of this process, one would be required to include the effects of thermal noise that might depend on a plethora of rate constants and thermodynamic parameters. in this paper  , we study the kinetics for nine of these pathways using the method of kinetic monte carlo, hereafter referred to as kmc. by simulating the aggregation kinetics in small volumes,   we show that the effect of statistical number fluctuations plays a significant role in both the equilibrium and the kinetic aspects of the kinetic of protein aggregation.
the role of two - body current effects in exclusive a(@xmath10 ) measurements from finite nuclei at higher momentum transfers ( @xmath14 ( gev / c)@x Math3 ) is investigated.   the results are compared with those of the pavia group and the mainz electron facility, which have previously reported on the effect of two-body current on the proton momentum distributions of exocyclic reactions at high momentum transfers for atomic nuclei @xcite.
we provide a general family of multi - agent justification logics, which we call @xmath10.   each member of this family is considered as a set of agents and the interactions between the agents justifications are described by binary relations on agents. for each of these logics   we provide semantics and a general tableau procedure, and then we make observations on the complexity of the derivation problem for its members. in particular, we demonstrate that all logics in this family have their satisfiability problem in - under reasonable assumptions.. this family demonstrates significant variety, as it also includes - and -complete members, while some of its members have their Satisfiability problem ( e.g., -completeness ).
the elastic force law of a long homopolypeptide capable of forming an @xmath4-helix is derived from two different treatments of the problem.   the first is based on free energy argument and allows for the polydispersity of the helical and coil domains and the associated mixing entropy. in the second   it neglects the direct coupling of the distribution of domains sizes and the applied tension. within this approach   we present a unified analysis of the problems, tracing the physical origins of the disagreements between the force laws obtained in the two earlier publications and analyzing their range of validity.
the stability of the einstein static universe in hoava - lifshitz gravity, with a ` soft'violation of the detailed balance condition, is considered.   the results show that the stability of this universe is modulated by the presence of a linear homogeneous perturbation term in the infrared limit of the theory. for a system with strong gravity at astrophysical scales, it is found that the stable modes for all equation of state parameters @xmath5 exist, if the parameters of the theoretical equations of state are chosen appropriately.
the origin of ultra - high - energy ( uhe ) cosmic rays ( crs ) is presently unknown.   however, there are numerous hints, both in data and in theory, which might help to constrain possible models of uhecr sources. even without a detailed modelling of the acceleration process,   a number of simple estimates rule out many classes of potential sources. for very special field configurations when synchrotron losses are suppressed and the curvature radiation dominates, possible acceleration sites include also gamma - ray bursts and immediate neighbourhood of supermassive black holes ( smbhs ) in the galactic nuclei. until now  , numerous attempts to model the sources of u hecrs and to confront theoretical predictions with experiments often assumed that these parameters are fixed once and for the entire universe. in this work, we attempt to present a toy model of numerous and different sources of Uhecrs from the immediate vicinity of smbh and, within certain assumptions, to confront it with the experimental data. as a result, we show that the acceleration capabilities of a source are determined by a single parameter, the smbh mass. at the same time, the demography of the sources is determined by the size of the
we have previously shown that the integrability of a model can be seen on the statistical properties of the entire spectrum of transfer matrices of vertex models. in this paper   we continue this work with the study of spin models.   first, we show that the spectrum of a spin model including only two - spin interactions, possibly coupled to an external field, is integrable and that it has the properties of a gaussian orthogonal ensemble ( goe ). for a time reversal symmetric model such as the eight - vertex model,   this is achieved using the so - called row - to - row transfer matrix analysis. when the interactions are nonchiral ( symmetric ), this can be done using the layer - to-layer in higher dimension analysis of the transfer matrix. for spin models and   when they are not symmetric, the analysis is performed using the top - down application of random matrix theory ( rmt ). by means of the yang   baxter equations, we find that the spin version of the star - triangle equations for the symmetric eight - vertices model is both yang - baxter Integrable as well as star - triangles integr
the zero - error communication problem of quantum channels is one of the most difficult problems in quantum information theory.   it is well known that the entanglement - assisted classical capacity of a quantum channel uniquely determines the properties of the channel in the simulation process, and that even with stronger resources such as no - signalling correlations or feedback, this rate can not be improved. to overcome this difficulty,   many variants of this problem have been proposed. here   we present a new approach to the problem by introducing quantum non - commutative graph theory into the problem. for any quantum channel, the bipartite graph of possible input - output transitions associated with the channel   captures the zero -error communication properties, thus playing a similar role to confusability graph. also, we introduce a quantum lovsz function to upper bound the entabler - assistedzero - error capacity that has properties quite similar to its classical analogue @xcite.
we have implemented a decision algorithm for fibonacci representation.   we have reproved many results in the literature about properties of automatic sequences, for which some had only long and involved proofs, as well as obtained new results, using this implementation. to prove these results, we have first phrased the property as an appropriate logical predicate, converted the predicate into an automaton accepting representations of integers for which the predicate is true, and examined the automaton. here  , we show that the latter can be proved with much less effort by phrasing them as logical predicates and employing a decision procedure. furthermore, many enumeration questions can be solved with a similar approach.
distributed quantum computing ( dqc ) is a possible solution to the problem of utilizing a network of limited capacity quantum computers.   a group of small quantum computers can simulate a quantum computer with a large number of qubits, and this approach is useful for the development of quantum computers because the earliest useful quantum computers will most likely hold only a small number of Qubits.. we propose that distributed quantum computing is a potential solution to this problem.    in this paper, we present two primitive operations, cat - entangler and cat - disentangler, which in turn can be used to implement non - local operations, e.g. a non -Local control not gate ( cnot ) and quantum teleportation protocol. using entangled pairs, we show how to establish an entangled pair between two nodes, and use entangled pairs to efficiently create a generalized greenberger - horne - zeilinger state ( also called a cat state ). by using quantum channels,   we also demonstrate how to transfer channel qubits back and forth over the network. furthermore, we describe procedures which allow us to reuse channel qu bits in a sequence of non -local operations.
we report results from two new atomic clock tests of local lorentz invariance ( lli ) and cpt symmetry for the neutron and proton, respectively.   we place a limit on cpt and lli violation of the neutron of nearly @xmath2 gev, improving by more than a factor of six on the best previous measurement. using a two - species zeeman maser, we also set an improved clean limit on lli / cpt violations of the proton at the level of nearly@xmath3 gev. these results are motivated by a standard model extension developed by kosteleck and others, which accommodates possible spontaneous violation of local Lorentz symmetry in a fundamental theory combining the standard model with gravity.
the interactions of domain walls ( dws ) in ferromagnetic stripes of nonzero thickness are studied.   narrow stripes correspond to the transverse dws while wider stripes to the vortex dws, both of which are exact stationary solutions to the landau - lifshitz - gilbert ( llg ) equation in 2d ( different realizations of the cross - tie dw @xcite ). for the first time, the field - induced collision of the dws of the opposite ( like ) chiralities and polarities is studied within a perturbation calculus previously developed with relevance to dws in 1d ferrom magnetic wire and in critical systems @xxcite. evaluating the dependence of energy of the two - dw systems on the distance between them,   the creation of stationary bound states of two dws ( magnetic bubbles ) is found to be possible.
globular clusters ( gcs ) in m31 are studied by fitting several structural models to their surface brightness profiles.   we have determined structures and kinematics for 79 clusters in the outer halo of m31 using the hubble space telescope ( _ hst_/wide field planetary camera 2 ( wfpc2 ) images, and found that most of the clusters have cuspy cores, with a mean diameter of about 1.5  0.8  km. among the clusters,   the core radius, half - light radius, tidal radius, and ellipticity are the most strongly correlated with the galactocentric distance from us, and the cluster size is the most closely related to the distance between us and the nearest large gc system outside the milky way ( m31 ), @xmath1 kpc.
we show that a modified logistic regression that ignores scores below a suitable threshold can benefit applications with low false - alarm rate requirements.   we extend on our previous work  @xcite, to demonstrate theoretically and experimentally that we can tailor proper scoring rules to target the low false-alarm region. given a database of supervised trials, the sum over trials of a proper scoring rule forms an objective function that can be used to simply evaluate the goodness of a recognizer with probabilistic output, and indeed also to facilitate discriminative training of such recognizers.
stripped supernovae ( sne ) and long - duration gamma - ray bursts ( long grbs ) are the most powerful explosions from massive stars.   they energize and enrich the interstellar medium, and, like beacons, they are visible over large cosmological distances. however, the mass and metallicity range of their progenitors is not known, nor the detailed physics of the explosion. here   i present a meta - analysis of published measured metallicities at the explosion site of stripped - envelope sne ( iib, ib, and ic, e.g., @xcite ) with and without grbs to elucidate the conditions and progenitor of these two types of explosions.
the time evolution of the relative entropy and rnyi entropies in the ising model of the critical ising chain is investigated numerically.   the results show that for truly local operators on the lattice, the cft answer is recovered, but for operators with non - local support  like ising energy  the subleading contributions modify the leading answer and lead to a mismatch. for states excited by more than a single local operator, the results are more complex and require the access to higher - point correlators.
the transformation of photometric observations from one filter system to another is rarely a trivial task.   this is especially true for observations of cool giants at near - ir wavelengths because of the presence of very deep molecular absorption bands that are dependent not only on stellar color, but also on absolute luminosity and stellar metallicity. in this paper   we present our hubble space telescope ( hst ) - multi - object spectrograph ( nicmos ) observations of 19 stars that have extensive ground - based observations on the cit / ctio grid of southern standards ( @xcite ; @xmath4b ). using the same single channel photometric system that was used to establish the cit/ctio grid as well as the nicmos filters, we have obtained measurements of the colors of these stars in three different filters : f110w ( @x Math10 ), f160w (@xmath11 ), and f222 m ( @Xmath12 ). by combining these measurements with the data from the ground-based observations, we were able to derive accurate color transformations for all of the stars, which span the color range of @x math0. the results are compared with those of ground
the origin of lenticular ( s0 ) galaxies is still a subject of much debate.   the internal kinematics of early - type galaxies are a key tool to understanding their structure and formation histories, and s0s are no exception. here   we study the radial surface density of planetary nebulae ( pne ) and globular clusters ( gcs ) in the halos of two s0 galaxies, ngc 1023 and ngc 1112, using a combination of high - resolution single - photon emission spectroscopy and magnetic resonance spectroscopic techniques.    the results show that the radial surfaces of the two galaxies are different in their pne subpopulations, with the red subpopulation being more abundant in the galaxy halos and the blue subpopulation more abundant at the outer edge of the galaxy disk. by combining these differences in pne and gc system properties  , we show that both galaxies have evolved from spirals that have been stripped of gas and that the red population of the gc systems is older than the blue population.
the detection of a single spin on a surface is possible by a scanning tunneling microscope ( stm ) on oxidized si(111 ) surface @xcite.   the technique is based on monitoring the noise, i.e. the stm current - current correlations, and observing a signal at the expected larmor frequency, a signal that is sharp even at room temperature. in the present work   we follow a recently proposed model that allows for an electron spin resonance ( esr ) - stm phenomena with non - polarized leads .    the model assumes an additional direct tunneling between the tip and the substrate in parallel to tunneling via the dot s states, i,e. a nanoscopic interferometer. 	 the numerical study@xcite shows that the interference of the direct current and that via the spin has an esr signal in the noise ; the signal is elongated and is maximal at @xmath2 nm on either side of a minimum point from the spin center. here, we evaluate the noise analytically in the stationary system, in accord with the numerical results for this case. using the hamiltonian of the system, we show that the signal increases
pfleiderer2 ( pwm2 ) is a low luminosity globular cluster in the galaxy.   it was found by @xcite on june 5, 6, 2008 with the 3.58 m galileo telescope ( tng ) at la palma, equipped with the dolores spectrograph focal reducer. to our knowledge, this is the first report of the discovery of an obscured and metal rich globular clusters in the same region of the Milky Way.
the dynamics of particles and their accumulation in electro - osmotic flow through micro - channel junctions, which are a basic element of microfluidic systems, have been investigated using sharp tips of @xcite.   the results show that the trapping of particles at the corner of a microchannel is due to a combination of the short range dep trapping force and the long - range induced electro - Osmotic vortex generated by the induced - charge electro-osmosis ( iceo ) mechanism at the edge of the microchannel. for a sufficiently strong external field,   this iceo vortex generates a non - linear electro - kinetic flow which feeds the particles into the stagnation point of the vortices via a combined forces of the dep and iceo mechanisms.. the particle trapping occurs due to the combination of a short range deuterium ( dep ) trapping force as well as an induced electrokinetic effect arising from the small yet finite dielectric polarizability of the walls of the wall materials.
the origin of irregular satellites and the mechanisms of their capture remain unknown.   it is believed that they were captured from the primordial circumplanetary disk from which the regular satellites of the giant planets were formed. in this paper  , we examine the possibility of a dynamical origin for the existence of a satellite - void boundary region between the orbit of callisto, the outermost galilean satellite at 26 jupiter - radii, and the periastron of themisto ( the innermost jovian irregular satellite ), which is void of irregulars. using a n - body capture model, we study the dynamics and stability of the orbits of several hundred test particles in a region interior to the orbit with a semimajor axis starting at @xmath2 and increasing in increments of 0.1 to 0.3@xmath3. by simulating the dynamics of these objects in their vicinities, we show that the orbital inclinations and eccentricities of the irregulars are significantly different from those of the regulars. given that the latter are formed through the collisional growth of small bodies in a circum Planetary disk, we hypothesize that perturbations from the
we study the potential of exploiting the properties of one - dimensional nonlinear photonic crystals in order to generate photon pairs with engineered spectral entanglement properties.   we focus on type - ii, frequency degenerate, collinear noncollinear parametric down - conversion ( pdc ) using a single - photon source and a broadband broadband pump. by controlling the effective group velocities of the three fields involved in the process of pdc, we can engineer the type and degree of correlations present in spectral and transverse wave - vector degrees of freedom at the source, thus permitting the generation of quantum - information - processing states with spectrally engineered properties. as a result  , we show that the energy of the generated photon pairs can be modulated by the combination of the crystal dispersion characteristics and the temporal and spatial structure of the pump beam, allowing for a short, high - finesse cavity which leads to factorable, narrowband photon pair generation.
the phenomenon of phase synchronization ( ps ), which describes the appearance of a phase synchronous behavior between two interacting chaotic systems, is recently called much attention due to the verification that it may be useful to the understanding of natural systems in a variety of fields as in ecology, in neuroscience, in economy, and in lasers.   we show how the conditional poincar map can be used to detect ps in a real - time experiment, without actually having to measure the phase of the chaotic trajectory. for phase - coherent oscillators, a special type of p - set, that we call ps - set ( phase synchronization set ),   is defined by collecting points in one oscillator at the moment at which some event happens in the other one. if the set of discrete points generated by this conditional map does not visit any arbitrary region of a especial projection of the chaos attractor, we call this set a * p -Set*. for non - phase - coherent oscillators such as the coupled rsller oscillator, the existence of these sets is verified by the detection of the p - sets in the forced chua s circuit and in the coupled rssler oscillator. using numerical and experimental analy
the lepton flavor violating ( lfv ) neutrinoless conversion of a bound 1s - muon to electron in the field of a nucleus @xcite-@xcite @xmath10 is known as one of the best probes to search for the hypothetical muon and electron flavor non - conservation @xaite.   so far, the experiments seeking for this process have only succeeded to put upper bounds on the branching ratio @x Math12 i.e. the ratio of the muon - electron conversion rate relative to the total rate of the ordinary muon capture. here   we use the transition matrix elements calculated for the aforementioned isotopes in the coherent mode to constrain the lepton Flavor violating parameters of various lagrangians predicting this exotic process ( e.g.  scalar and vector couplings, neutrino mixing angles and masses, supersymmetric r - parity violating couplings etc. ). to this aim the recent experimental data and the expected sensitivity of the planned meco experiment at brookhaven using @xMath5al target   are compared.
mixed versions of general relativity have been proposed as serious alternatives to einstein s theory of gravitation.   recently, different models of that kind have been studied @xcite, the last three of them having been reported to pass all solar system tests ; in addition, they exhibit a number of very interesting features. here   we present here an analysis of the models above based on the study of pure schwarzschild and also schwarzschild - de sitter black holes ( sbh, sdsbh ), calculated through use of the noether charge method. using this method, we show that the black hole entropy can be directly confronted with the well established, classical ( einsteinian ) result for the curvature function @xmath0, and that it can be used to give rise to a more realistic model of modified gravity.
time itself has remained one - dimensional since the time of newton, but it is not clear what a world with multiple times looks like.   the recent work of walter craig and myself explores the features one might expect in a theory with multiple time dimensions from a mathematical perspective. using the wave equation for the massless scalar field described by the ` wave equation ',   we show that if we are given sufficient information about the field at a given time, a stable solution of the equation exists, and it is unique. as i ll show, such theories allow a meaningful sense of determinism, while giving rise to intriguingly nonlocal constraints on initial data. furthermore, the way in which these sorts of constraints arise, from a reconception of the structure of the spacetime background, suggests heretofore unexplored ways of extending physical theory.
we re - examine the renormalisation of the non - anticommutative wess - zumino model of quantum field theories in four dimensions.   we show that the one - loop corrections for this model can be computed by renormalising the auxiliary fields of the grassmann co - ordinates @xmath1,@xmath2, while leaving the anticomplementators of the supersymmetry generators @x Math3 and @x math4 unaltered. to obtain results for the theory where these auxiliary fields have been eliminated from those for the uneliminated theory, it is necessary to include in the classical action separate couplings for all the terms which may be generated by the renormisation process.. the results obtained when we eliminate the auxiliary field after renormalisations are equivalent to those obtained when they are eliminated before quantisation.
the first measurement of the inclusive isolated photon cross section in run 2 of the tevatron hadron - collider @xcite at large @xmath0  provides one of the cleanest and most accurate tests of perturbative qcd ( pqcd ).   the measurement agrees well with next - to - leading order ( nlo ) theory over six orders of magnitude and is expected to be useful for constraining parton distribution functions ( pdfs ) independently of the high-@x math0 jet production.
the present paper introduces a new sheaf - theoretic framework permitting an explicit construction of arbitrarily charged magnetic monopoles.   this framework is likewise applied to generic @xmath1-bundles and yields, as a by - product, the notion of a quasispin structure defined on arbitrary space - times. in this context, the results suggest that topological quantisation in general can be viewed from a more flexible perspective.
the presence and location of corotation resonances in barred spiral galaxies is important for several reasons.   first, resonances are required by density wave theory, so their existence would be evidence that supports the theory. here  , we use the puerari & dottori ( pd ) method to measure the corotation resonance ( cr ) radii and relative bar pattern speed of 15 barred - spiral galaxies that have already been measured with the tremaine - weinberg method ( tw ). using the pd method, we find that the cr radii of the galaxies range from 0.1 to 1.0 bar lengths.    the relative bar patterns are also found to be very fast, ranging from 2.2 to 3.5 bar lengths ; however, the radial radius of the bar can not be larger than its corotation radius, or the bar would not be self - sustaining because it does not transfer angular momentum outwards. on the basis of these results, we propose that the galaxy has a bar - like structure with its own pattern speed which is independent of the orbital speeds of stars and gas in the disk.
the stability and structure of super - heavy elements ( she s ) at the upper end of the nuclear chart is a hot topic in contemporary nuclear physics.   it is a challenging task to answer which heavy nuclides may exist and what properties they may have. in the last decades   a huge progress in the synthesis of new elements has been achieved in world leading laboratories like the gsi, darmstadt, jinr, dubna, and riken, tokyo @xcite. in a parallel way to the experimental efforts, the properties of the she s have been also investigated in various nuclear models. here   we review the current knowledge on the stability and properties of she s using self - consistent quantum mechanical methods.
one of the fundamental hot debated problems in bosonic physics concerns the evolution of the charge ordered ( co ) ground state of 2d hard - core bose - hubbard model ( hc - bh ) with a doping away from half - filling.   the most commonly discussed " checkerboard " supersolid is thermodynamically unstable and phase separates into solid and superfluid phases. here   we present a topological scenario of co+bs phase separation in 2d hc-bh model with inter - site repulsion where the extra bosons / holes doped to a Checkerboard co phase are believed to be confined in the ring - shaped domain wall of the skyrmion - like topological defect which looks like a bubble domain in an easy - axis antiferromagnet. by using a simple mean - field approximation ( mfa ) and classical continuum model  , we show that the structure of the phase separated state is similar to that of the pure 2d t - j model, in the small - j / t regime and with dopings near @xmath5, but the quantum monte - carlo simulations have a striped ground state instead of a striped one.
the ground state of the holstein  model of strongly coupled electron - phonon systems changes from the delocalized polaron state, in which the electron is nearly free, to the small and self - trapped polaron states, as the coupling increases.   the main goal of this paper is to determine the elements important for the qualitative description of the polarons in the whole range of electron - phasic coupling. by comparison to the results of other methods,   it is shown that the new method uses variational approach in order to define and solve the generalized eigenvalue problem. a new method is proposed for the calculation of the ground state energy of the self - trapping polaron in the weak and strong coupling regimes, which is based on the exact diagonalization of the localized Polaron states.. the experimental results show that the method does not converge systematically, but it does provide new results concerning the nature of the polaron ground and first excited states.
we have recently shown that layered sine - gordon type models are probably not suitable for the description of josephson - coupled layered superconductors, because the linear, confining potential that binds the vortices together can not be obtained from the interaction of the topological excitations of the model, no matter how the interlayer interaction term is chosen  @xcite.   we also observe that recently, there is an increasing interest in the literature in constructing sine  gordon types of field theoretical models in order to understand better the vortex dynamics in layered superconductor systems. in this paper, we present a two - dimensional multi - layer sine-gordon type model which can be used to describe the vortex behaviour of magnetically as opposed to josephalic - coupled layers and to contrast and enhance our recent investigation of the vortex dominated properties of high @xmath0 layered superlattices  . the model is constructed on the basis of the real space renormalization - group analysis of the case @x math6 using the dilute gas approximation. by means of the entropy method,   the structure of the multidimensional vortex stack is broken up into a number of
a simple model of layered diffusion in a wetting layer is proposed.   the model is based on the fact that the properties of motion of molecules in such layered structures are independent on the particle s lateral position due to translational symmetry of the fluid layer in this direction, while the properties for diffusion in the other direction depend on the distance from the surface ( i.e. on its @xmath1-coordinate ). by applying the model to the experimental work @xcite, it is shown that the observed vertical diffusion coefficient is smaller than the theoretical one and the lateral diffusion is anomalous for short times and crosses over to normal diffusion for long times.
the " shot effect " in electron emission is a well - known property of phase - coherent conductors.   it was first discovered by schottky almost a century ago, and has been studied intensively in quantum point contacts ( qpcs ) and vacuum tubes. in both cases, the granularity of charge is manifested in the shot noise, although the source of randomness is different : @xcite in qpc, the randomness appears in the transmission process due to the quantum partitioning between the incoming and outgoing states ( the incoming carriers are noiseless ). in vacuum tubes,   the randomity is an inherent property of the emitter caused by thermal fluctuations. in this paper   we show that in new generation electron emitters, scaled down to the nanometer dimensions, shot noise much smaller than the schottsky noise, due to a quantum partitioned effect, is observable. moreover, two different sources of randomism  thermal agitations and quantum partitions  may act together governing the electron emission noise.
the patrolling of an environment by a team of mobile robots is a challenging problem.   the patrolling problem requires the robots to continuously and repeatedly travel the environment, and the challenging problem consists in scheduling the robots trajectories so as to optimize a certain performance criteria. here  , we present a solution to the problem by means of some graph partitioning and graph routing techniques. using these techniques, we show that cyclic - based strategies are to be preferred whenever the ratio of the longest to the shortest edge of the graph describing the environment is small, while, otherwise, partition - based policies exhibit better performance.
in the late 70 s, montonen and olive discovered that a given four dimensional gauge theory might be described using different sets of elementary fields @xcite.   the fields in one of this set create the standard perturbative spectrum of the theory ( photon, w bosons, quarks,  ), while the field fields in the " dual " set correspond to the solitonic states ( dyons ). here  , i study the bps spectra of two theories with zero @xmath8 function : the so(3 ) gauge theory with one flavour of bare mass@xmath11 and the su(2 ) gauge theoretical with four hypermultiplets@x Math13, @x math14.    the first one is the so gauge theory, which is known to be conformally invariant at the quantum level, perturbatively @x maths1 as well as non - perturbably @x mathematics2. for the second one,   it is possible to go continuously from weak coupling to strong coupling without altering the stability of the states. both theories have been shown to be compatible with an exact electric - magnetic duality symmetry, which implies that the @
the schrdinger map equation for ferromagnetism is a well - known model of the dynamics of a vortex filament under the euler equations.   it is also known as the landau - lifshitz equation, and it has been used in the literature to study the fractal character of the fiber architecture of the vortex filament equation.. however, the relationship between fractals and the schrdingers map equation is not new ; indeed, in @xcite, an aortic valve model was proposed, in which the fibers were modeled as curves with a fractal dimension. here  , we review the results of numerical studies of the self - similar solutions of the nonlinear sch thirdinger ( nls ) equation for the euclidean and the hyperbolic cases of the vfe model, and we discuss its limitations.
the storage and transmission of quantum states in a decohering environment is unavoidable in quantum computation and quantum communication.   the conceptual device of a quantum channel is very useful in addressing the issues of such a transmission and to analyze decoherence related questions in quantum cryptography and quantum telecommunication. in this paper  , we investigate the role of a one - qubit mixed state environment in the simulation of a single qubit quantum channel by computing the set of affine transformations for generalized depolarizing channels using the canonical form for two - qu bit unitary operators. restricting ourselves to generalized depolishing channels,   we show that a sizable volume ( namely @xmath3 ) of these channels can not be simulated by a one-qubit mixedState environment.    further, we show how the counter example of the two - pauli channel found by terhal et al. is a special case of our results.
according to the standard big bang nucleosynthesis ( sbbn ), the most abundant elements in the aftermath of the big bang were hydrogen and helium with very small traces of deuterium and lithium.   these elements make up the so called pop iii or  primordial  chemical composition. in order to understand the physics of the early universe  , there is a need of having appropriate and accurate material functions at hand, in particular opacities for a s bbn chemical composition.in this paper we present calculations of both, rosseland and planck mean opacity sets for primordial matter including all the three elements ( hydrogen, helium, and lithium ) including deuteroium isotope and present their absorption properties.we show that the observed abundances of these elements are consistent with cosmological parameters, while the observed li abundance still lacks a factor of 3 compared to the Sbbn results.  also, we show that it is possible to estimate the time needed to reach chemical equilibrium by comparing our results to previous tabulations.
the nature of anomalous x - ray pulsars ( axps ) has been a mystery since the discovery of the first example ( 1e  2259 + 586 ) nearly 20 years ago ( @xcite ).   recently, it has been argued that the axps are young, isolated, highly magnetized neutron stars or " magnetars ". here   we report on observations made with the _ rossi x - rays timing explorer _ ( _ rxte _ ) in which, for the first time, we determine high - precision spin parameters using long - term phase - coherent timing of two axps : 1rxs  j170849.0@xmath0400910(@xaicite ) and 1e2259+586  ( @xeicite).the results show that the observed spin parameters are in good agreement with the inferred spin - down ages from the magnetar hypothesis. however, the observed braking index is much lower than the rate of loss of rotational kinetic energy inferred from the observation of the spin-down. to obtain a reliable measurement of the braking index, we have to take into account the acceleration of the pulsar as it spins down.
this paper aims to construct new and effective the second - order mid - point approximate formula for time riemann - liouville derivative.   then the established scheme is applied to time fractional cable equations in one and two space dimensions. by using the energy method,   the unconditional stability and convergence of the established numerical algorithms are presented by the first approximation formula is established.. then two high - order finite difference schemes for the fractional cables in one- and two-space dimensions are proposed. finally, the numerical experiments are displayed in line with the theoretical analysis.
the outbreak of ebola virus disease ( evd ) in west africa 2014 revealed many challenges in predicting and controlling the spread of infectious diseases.   these challenges are partly related to the mathematical modeling of the dynamics of the epidemic. providing accurate predictions appeared to be extremely difficult. to address these challenges, several new models have been suggested each providing quite different results, for example @xcite. in this paper   we propose an alternative control mechanism to decrease the transmission of infection based on the model developed in@xcite where the transmission rate and the average time of isolation are considered as the main parameters.the main dynamic parameter in our model is @xmath8 and all the intervention measures are directed at decreasing @x Math8 and consequently reducing the spreading of infection.the most important component of the suggested model is the optimal distribution of bed capabilities across countries / regions. by considering the average times for isolation as a time - dependent parameter, the model can be used to predict the future spread of the disease.
active magnetic bearings ( ambs ) are being employed in a variety of rotating machines, including compressors, milling spindles, and flywheels.   they are normally operated by introducing a sufficiently high, fixed magnetic flux in each electromagnet, which is referred to as the bias flux, and then setting the bias value to a fraction of the saturation flux of the electromagneurons. while this conservative practice facilitates the design of the amb'control'flux, it also increases electric power losses in the amb system, causing rotor heating and affecting the machine efficiency. here  , we present a new approach to stabilizing the amb model of @xcite using a _ forwarding - like _ method that allows the use of different saturation functions ( both ` hard'and ` soft'), thus providing more flexibility in the control implementation ; and we provide an explicit construction for a ` global'control lyapunov function ( clf ) for the system.
the dynamics of micron and nanoscale cantilevers are important to a wide variety of technologies including the invention of the atomic force microscope ( afm ), which relies upon the dynamics of a cantilever a few hundred microns in length.   the ultimate force sensitivity of a particular measurement is limited by the inherent thermal noise of the experimental system. as experimental measurement continues to push toward the stochastic limit it is important that we build a physical understanding of the fluid - coupled dynamics of these cantileverns for the precise conditions of experiment including complex cantilevals, the effects of nearby walls, and the fluid coupling dynamics of multiple Cantilevers in an array configuration.    we present a new method for measuring the cross - correlations between two micron scale cantilevs in a viscous fluid using the knudsen number and the strouhal number as the nonlinear inertial terms. with this method   we show that the frequency based reynolds number can be used to measure the interactions between two cantileVERs in aqueous fluid with unprecedented force sensitivity and time resolution.
we propose a method for the fabrication of spatially isolated entangled atomic populations using a three - well bose - hubbard model.   we show that this can split an initial condensate in the central well into two separated entangled condensates, with the detection of the entanglement being sensitive to both the initial quantum state of the condensating atom in the centre well, and to the criteria used to determine the entangling properties. by comparing the performance of the proposed method to that of an optical beamsplitter for the production of spartially separated output modes, we find that the latter is more sensitive to the quadrature based criteria used.
the quantum dynamics of photosynthesis have attracted a lot of attention recently.   the quantum coherence effects in light harvesting complexes ( time scale of 1 - 500 fs ) have been addressed theoretically and experimentally @xcite. here   we focus on reaction center quantum dynamics, i.e., photo - excited radical - ion pairs ( rps ), which are formed by electron transfer reactions between the donor - acceptor dyad pi and the quinone q@xmath2 at different recombination rates, as well as the spin - dependent recombination of singlet ( triplet ) radical pairs at different rates. to address the question of whether these processes are governed by quantum ( de)coherence, we discuss the recent advances in our understanding of the quantum interactions between the rp and the external magnetic field, with particular emphasis on the role of nuclear spin sorting in the formation of cidnp, a signature of spin order in photosynthetic reaction centers.
the x - ray emission of 25 members of the old open cluster rosat pspc is unexplained.   we investigate the nature of the emission by looking for emission cores in the h&k lines, and derive projected rotational velocities with the crosscorrelation method. using this method, we find that the emission is coronal as a consequence of magnetic activity in two ( sub)giant branch binaries, s1063 and s1113, which are located away from the isochrone formed by the main sequence and the ( sub ) g2 branch of the cluster. to determine whether the emission could be due to mass transfer or magnetic activity, we study the h@xmath0 profile of the binary through low- and high - resolution optical spectra at different resolutions. in both cases,   the emission cores are found to be photometrically variable with @xmath7 0.10 mag ; however, the orbital periods of the two binaries are too long for them to be contact binaries. also, they are too far above the main sequences to be binaries of main - sequence stars.    the observed emission cores show that the emissions are caused by tidal interaction in a close binary
the spatial inhomogeneity of a superfluid fermi gas can affect its physical properties.   this paper explores the possibility that a triplet superfluid state can be induced in a trapped @xmath0-wave superfluid, when a spin rotation symmetry of this system is also broken, in addition to the broken inversion symmetry by a trap potential. using symmetry considerations, we prove that this phenomenon may occur, when both the spin rotation and spatial inversion symmetries are broken.
the growth mechanism of pentacene thin films on gold and silver surfaces has been studied at the dft level using gga functionals.   the results show that the first layer of adsorbedpentacene molecules is a monolayer phase on au(111 ) surfaces, while the second layer forms a multilayer phase in the same way as the first one on ag(111)/u(111)(111 ) surface. for both surfaces the formation of the ordered bilayer film structure   is dependent on the strength of the aromatic-@xmath4-system metal substrate interaction ( @xcite ) between the molecule and the substrate.. the most stable configuration is found to be the pentacenes lying flat on the surface  @xcites  while the other two configurations are more prone to chemisorption / dewetting depending on the type of substrate.
we have developed a simple model to simulate the compaction of a packing of monosize spheres submitted to vertical taps.   the model is based on the notion of free volume and geometric constraint between hard spheres, which are the only ingredients of the model. as a three - dimensional model,   our description has the quite interesting asset that it is very close to a real granular medium. despite the fact that we deliberately forgot the mechanical dimension of the problem, the model can reproduce qualitatively the experimental results of the chicago group and some further results in agreement with different numerical and theoretical studies.
the radio - loud gravitational lenses b1600 + 434  and b1608 + 656  were discovered in the cosmic lens all sky survey @xcite.   one of the important applications of gravitational lenses is to constrain the hubble constant or alternatively, the dark matter distribution in the lens galaxy, through time - delay measurements between the lensed images. in this paper  , we present results from _ chandra _  observations of these two gravitational lenses with the advanced ccd imaging spectrometer ( acis ; garmire et  al., 2003 ) onboard_chandra  for @xmath17  ks and@xmath18  k s on 2003   october 7, and 2003 september 21, respectively. during the observations,   the x - ray emission from the galaxy groups or clusters close to the gravitational lenses was measured by using a single - photon emission computed tomography ( pet ) technique.. the results show that the presence of galaxy groups near the lens galaxies is non - negligible. however, the size of the galaxy clusters or groups at the lenses is small enough to limit the distance between the quasar and the lens Galaxy.
pseudocontinuability is a particular type of meromorphic continuation for functions from the meromorphic nevanlinna class in the unit disk.   this concept originated in shapiro s papers @xcite,@xcite and was then systematically discussed a little bit later in the context of invariant subspaces for the backward shift in the landmark paper douglas / shaproi / shields @xmath0.    the present paper continues recent investigations on several questions of pseudocontInuability of schur functions in the units disk. here   we introduce a new characterization of pseudo - inner schur function @x Math0 in theunit disk which is expressed in terms of a special orthogonal basis in an @x maths3 space on the unit circle, where @x math1 is some probability measure on the Unit Circle which is canonically associated with @xMath0.
we have recently shown that spontaneous symmetry breaking imposes a fundamental limit for the time that a large spin system can stay quantum coherent.   this universal time - scale is @xmath0, given in terms of the number of microscopic degrees of freedom, temperature, and the constants of planck and boltzmann.the goal of this paper is to present a self - contained, detailed description and explanation of the decoherence process caused by spontaneous symmetric breaking. within this spin model   we investigate the dynamical reduction of quantum physics to classical behavior via spontaneous asymmetry breaking. using a generic gedanken experiment  , we show that the intrinsic coherence time for a macroscopic antiferromagnet in equilibrium is ~1.5 centuries. however, multiplying with avogadro s number yields ~9 centuries.    the counterintuitive feature of this intrinsic decay mechanism linked to classical equilibrium is that it starts to matter when systems become small.
density functional theory ( dft ) is a popular method for studying materials and molecules at the atomic scale.   recently, there has been an increasing interest in using uniform real - space grids and finite - difference methods for doing dft calculations@xcite. here   we present a new method for performing dft computations using the projector augmented wave ( paw ) method based on real- and plane - wave representations of the wave functions. to our knowledge, until now, all applications of grid - based electronic structure calculations have used norm - conserving pseudopotentials or ultra - soft pseudopotential methods. however, the paw method is an all - electron method within the frozen core approximation, giving access to the true wave functions and the full electron density. as a result, we have decided to use the real - time paw method for solving the poisson s equation and the kohn - sham equations. with this method, we are able to reproduce results for atomization energies from all - echocardiographic dft calculation with high accuracy.
mergers are a common and important way of building up massive elliptical galaxies. with the presence of supermassive black holes in the centers of most galaxies,   merger processes are thought to have left signatures on the central structure of the remnant galaxies.   @xcite suggest that a binary black hole that is formed by the merger of two galaxies scours the stars from the center of the newly created system as the binary shrinks. here   we investigate the relationship between the core properties of the merger remnant and the size of the central mass deficit ( or the mass ejected by the binary ) with respect to the merger history. using a series of galaxy profiles from the hubble space telescope, we find that the diameter of the power - law cusp in the inner part of the core can be used to quantify the mass deficit existing before the coalescence stage of the binary. for a single merger, the mean core size is about 10.5 times larger than the total mass of the merged black hole, while for multiple mergers it is about 1.5 orders of magnitude smaller.
the nucleation of microscopic crystallites in polymer liquids is profoundly influenced by flow.   flow - induced crystallization ( fic ) is a fascinating example of an externally driven, non - equilibrium phase transition, controlled by kinetics. the widely postulated mechanism for fic states that flow forces the polymer chains into elongated configurations, which lowers the entropic penalty for crystallization, has yet to be developed into a quantitative molecular model. at a much higher level of coarse - graining, models based on differential equations either assume an empirical dependence of the nucleation rate on the flow conditions, the stress tensor, or the chain stretch @xcite ; or assert that free energy changes under flow can be directly subtracted from the nucleus nucleation barrier. in either case   the postulated fic mechanism remains untested. here   we present coarse -grained kinetic monte carlo simulations of anisotropic nucleation in flowing polymers using a recent molecular flow model that reliably predicts both neutron scattering and bulk stresses. our simulations predict both enhanced nucleation and elongated shish nuclei.
minimizers of a submodular function form a distributive lattice, and are compactly represented by a poset ( partially ordered set ) via birkhoff representation theorem.   this fact reveals a useful hierarchical structure of the minimizers, and is applied to the dm - decomposition of matrices and further refined block - triangular decompositions  @xcite. in this paper, we address such a birk Hoffman - type representation for minimizers of an @xmath0-submodular functions via a _ poset with inconsistent pairs ( pip ) representation. here  , we present algorithms to construct the elementary pip of the minimalizer set of a @x Math1-sub modular function under three situations : network - representable, potts - energy - based, and polynomial - based. our results consist of structural and algorithmic ones.
the detection of delayed x - ray, optical and radio emission, " afterglow ", following a gamma - ray bromide ( grb ) is reasonably described by synchrotron emission of relativistic electrons from the heated matter.   we derive the basic formula for the observed flux from a system moving relativistically, and show that both the light curve and the spectra are flat near the peak. in three alternative magnetic field models,   the light curves and spectra remain flat at the peak in all the cases we consider.
we study the thermal evolution of a proto - neutron star as it cools via heat diffusion via neutrinos in dense, color superconducting quark matter.   we find that the neutrino mean free path in the superconductor phase has a strong dependence on temperature and is strongly influenced by the energy gap between the quark chemical potential and the fermionic excitation spectrum. at low temperatures,   the temperature dependence is exponential, but at higher temperatures it is not so. for the intermediate regime, when temperatures pass through the critical @xmath20 temperature, the cooling process is uniquely uneven, marked by a slowdown of the cooling rate when the system undergoes a second - order phase transition.
dark matter halos are the building blocks of the universe.   knowledge of the formation and evolution history of these halos is essential for an understanding of the halos structure and dynamics, as well as the environment that harbors galaxies and clusters. in this paper   we propose a cosmological kinetic theory for dark matter halo evolution in the presence of a spectrum of density fluctuations based on the fluctuation - dissipation theorem for time - dependent stochastic processes. by focusing on the phase - space distribution of dark matter in galaxy halos instead of on the motion of a mass shell ( as in infall models ) or the orbit of a simulation particle ( n - body simulations )  , we attempt to understand the evolution of the phase- and mass - space distributions with a statistical description based on kinetic theory. using the radial infall model and n -Body simulations, we find that dark matter Halos evolve in a manner that is different from that predicted by the latter two models : they rarely form and evolve in isolation, growing instead by frequent accretion of smaller - mass halos and occasional major mergers with other halos of comparable mass.
intermediate scale disk galaxies with starbursts are relatively common in the nearby universe.   many of these occur in smaller galaxies, produce blue colors and strong emission lines, and are in gas rich systems, as indicated by their relatively large fractional high - energy ( hi ) content. here   we review the local analogs of the faint blue compact narrow emission line galaxies ( cnelgs ), which become common at redshifts of z@xmath40.3.
the phenomenon of chaotic advection, with its characteristic stretching and folding of material elements, is able to bring distant parts of the fluid into intimate contact and thus greatly enhances mixing by molecular diffusion acting at small scales.   the interaction between the stirring process and the chemical activity can result in complex patterns for the spatial distribution of the chemical fields, which in turn greatly affect the chemical processes occurring in the fluid. in this paper   we focus on such non - uniformities of the filamental chemical field and study how this affects scaling properties of quantities involving spatial averages, which are the more convenient quantities to be observed in experiments. as time - scales of the system are varied  , the resulting concentration distribution can be smooth ( differentiable ) or exhibits characteristic filamental patterns that are nowhere differentiable except in the direction of filaments aligned with the unstable foliation induced in the liquid by the chaotic dynamics. in the case of mixing by open flows,   these patterns are characterized by a smooth - filamental transition and the dominant value of the hlder exponent. in closed flows, however, the same problem is not always present. in order to obtain a quantitative characterization of the structure functions of the structures in terms of
the pion induced double charge exchange ( dcx ) reaction in light nuclei @xcite has been extensively studied at energies below and around the @xmath7 resonance.   however, many questions remain not sufficiently understood, like the angular dependence of the analog transitions at resonance energy@xcite, or the two - peaks structure of the spectra at forward angles that appear in the inclusive dcx process. here   we present a monte carlo simulation of the dcx for all nuclei at energies between.5 gev and.10 gev using a variant of the cascade model proposed for the exclusive reaction in @xaicite. by combining the results of calculations of pion spectra from experiments and simulations  , we show that the quantum interference effects of the sequential mechanism are negligible at very low energies. at higher energies,   the contribution of the quasielastic scattering mechanism is expected to decrease rapidly, and the contributions of the single charge exchange mechanism and the absorption mechanism are expected to be negligible.
we take an alternative approach for minimizing, based on an identity that is well - known in some areas of statistics, but appears to have received relatively little attention for its computational implications in large - scale problems.   the identity between the true minimizer of the population risk and the ordinary least squares ( ols ) estimator is a relationship that was first identified by fisher in the 1930s, and it has been shown to be approximately proportional to the ols estimator in the random predictor ( design ) setting, regardless of the covariate ( predictor ) distribution. here  , we show that this relation still holds under certain types of regularization, and we design a computationally efficient estimator for @xmath16 by first estimating the ol s estimator, which is then used to estimate the true optimality of the empirical risk minimization given in. using this method, we find that the estimation of the proportionality constant of proportionality is not necessary for the optimization of the stochastic optimization problem, and can be performed by computing the ool estimator instead.
the understanding of the qcd phase diagram has become one of the most interesting issues in the physics of strong interactions.   the nambu - jona - lasinio model of the nonlocal chiral quark model@xcite is a well - known extension of the local effective model of qcd, which is based on the interaction of the quark fields via local four point vertices which are subject to chiral symmetry. in this model,   if such interaction is strong enough, chiral symmetry is spontaneously broken at zero temperature and density, and pseudoscalar goldstone bosons appear. as an improvement on the local njl model, some covariant nonlocal extensions have been studied in the last few years. in the present work   we extend these studies to the case in which a superconducting phase can appear. for the case of two light flavors and @xmath5 isospin symmetry, we show that the effect of the diquark correlations on the strength of the chiral phase transition is weakly dependent on the euclidean action of the raman - induced quark - quark interactions. by taking into account the fact that the energy of
the generation and the dynamics of self - bound large quantum waves have drawn much attention lately.   there have been some theoretical suggestions for generating a quantum ball, in the presence of a repulsive core in the two - body atomic interaction, but so far there has not been success in their experimental realization. in this paper   we demonstrate that a _ very small _ repulsive three - body interaction in the absence of an attractive two -body contact interaction can generate a stable quantum ball.. the collapse is stopped in this case by the repulsive four - body contact interaction.    we consider the mean - field gross - pitaevskii equation with the inclusion of a three -Body interaction for the study of statics and dynamics of a quantum balls. erytheoretical calculations show that the quantum balls are bound by an attractive 2d contact interaction in which the center of gravity is at the surface of the quantum ball and the outer edge of the ball is near the ground state. to investigate the interaction dynamics of these quantum balls with other objects, we use realistic parameters of @xmath0li atoms, with a negative scattering length corresponding to two- and three - bodies attraction, and experimentally observe
charge ordered states play an important role in underdoped cuprates.   it is the aim of this paper to characterize charge ordered state in interacting systems independently of the strength of the interaction. by exploiting point group and time reversal symmetries as well as the hermiticity of the hamiltonian for the order parameter ( op ) for the bond - order wave ( bow ) state @xcite we show that the bow state is a nonlocal charge density wave state where the charge density waves acquire an internal degree of freedom because the electron and hole occupy different sites. at zero doping of the staggered flux phase,   both kinds of charge order are independent from each other showing that the formation of the pseudogap, fermi pockets and the appearance of quantum oscillations may thus be intimately related in these systems.
the energy resolution of scintillation crystals is parametrized by the light yield ( ly ), defined as the number of photons emitted per unit of absorbed energy.   the @xmath1/@xmath2 ly of a crystal is not constant with the energy deposited inside the lattice, and this characteristic, referred to as  non - proportionality _,  prevents the correct reconstruction of the absorbed energy, affecting the energy calibration. in recent years   great importance has been given to the study of the influence of the shaping time used to shape the light signals on the ly of crystals, because of its correlation with the attainable energy resolution. in order to characterize the crystal independently from the detector, the ly dependence on shaping time   has been measured as a relative variation with respect to the ly at the 662 kev @x Math1 line, known as  relative light yield  ( @x math4 ). in this paper   an in depth analysis of the effect of shaping time on the x - ray diffraction properties of three crystals with different time and light output characteristics : cdwo@x maths0, bgo, and nai(tl ) @xcite is
we present a numerical study of exact breather dynamics in two - dimensional anisotropic nonlinear schrdinger lattices.   the existence of discrete breathers in these systems has been proved rigorously in @xcite for a number of equations with physical relevance and, contrary to continuous nonlinear equations, their existence can be regarded as a generic feature of these systems. here   we focus on the computation of numerically exact dicrete Breathers in two-dimensional anisotropes of the salerno lattice, where the couplings in the two spatial directions are different. using shooting methods  , we find the exact solutions of the standard nonlinear Schrdinger equation for the localized breathing problem in the lattice and analyze their structural and stability properties. both pinned and mobile discrete breathing solutions are studied. in the latter case   only the ones whose motion is along one axis of the lattace are studied.the analysis of the numerically exactly exact solutions sheds light on some features of the properties and stability of localized solutions reported in previous works.
the magnetic anisotropy and coercivity of mnbi crystallites grown from a melt with excess bi atoms in a magnetic field has been studied by neutron diffraction, nuclear magnetic resonance ( nmr ), and magnetization measurements on single crystals.   the results show that the ferromagnetism in mnbnbi vanishes abruptly upon heating above 630 k @xcite, and the phase transition that occurs near 630 k is not a typical magnetic transition but a peritectic decomposition of nias - type crystal structure involving the formation of a ferromagnetic phase with a curie temperature well below the decomposition temperature at which the mn rich phase is formed.
the existence of a mass gap for the gluon propagator in the landau gauge in the deep infrared is confirmed by the spectrum @xcite.   this fundamental result can be used to perform computations in quantum chromodynamics ( qcd ) at low energies. here   we show that the nambu - jona - lasinio ( nnjl ) model, which we have previously shown to describe the low energy phenomenology of hadron physics, has a role as a low energy limit of qcd and obtaining higher order corrections is needed due exactly to this role. using a two - quark qcd theory with the u and d quarks having zero mass, we prove that the eight quark interaction term does not change the critical temperature for the chiral transition. finally, we provide a sound motivation to the existence of such higher order terms in the nnl model deriving them directly from qcd.
we define the third and fourth moment variations of financial asset return process and examine the properties of the variations.   the third moment variation is defined to be a quadratic covariation between squared return and return process ( realized variance ) and the fourth moment variation, which is aquadratic variation of squared return process, is defined for the purpose of estimating the true third moment of long - horizon returns. in this study, we propose a new definition of the realized third moment which satisfies the aggregate property to estimate the true second moment of high - frequency returns. using the new definition, we show that the risk - neutral expectation of the quadrastic variation of the return is synthesized by a continuum of european option prices and the variance risk - premium is generally larger than realized variance. under the presence of a jump in physical probability,   there is a fixed variance swap rate which is the value in which investors are willing to pay to protect their assets from the risk of an increase in the variance of return under the physical probability and the risk-neutral probability..the results of this study are discussed in terms of the relationship between the variables and the corresponding quantities of the returned distribution.
localization systems have found widespread application, since they allow to develop a number of new services in both outdoor and indoor environments.   conventional localization systems acquire positional information from a set of observations ; these are usually extracted from noisy wireless signals propagating in harsh environments. in this paper, novel accuracy bounds for map - aware localization systems are developed and their applications to specific environments are analysed. specifically, the bayesian cramer - rao bounds ( bcrb ), the extended zik - zakai bound ( ezzb ) and the weiss - weinstein bound ( wwb ) for the above mentioned systems are derived and evaluated.the results show that maps should be expected to play a significant role at low signal - to - noise ratios ( snrs ) and in the presence of obstructions ; however, the impact of map - awareness on the performance limits of localization systems is still an open problem.
the existence of a variable dark energy ( de ) has been postulated to account for the accelerated expansion of the universe.   we review the current state - of - the - art models of de that have been proposed to explain this property and discuss how they differ from the simplest possibility of de being a cosmological constant, which is based on the observation of several independent observations including those of high redshift type ia supernovae, and the cosmic microwave background ( cmb ) combined with the large scale structure of the Universe @xcite. in all cases,   the observed properties of the currently observed ` late de'are qualitatively similar to those of an ` early de'which is believed to have given rise to accelerated expansion in the early universe. therefore, it is natural to conjecture by analogy that the same might also be true of'late de'.we propose a new class of de models which assume that the origin of the present cosmic acceleration is not related to strong, electromagnetic or weak interactions but rather to the vacuum energy of the interaction responsible for the non - zero neutrino rest - masses. as a consequence, the quantum field equations governing the evolution of the ( observed part of the )
the theory of compositeness has been in use to explain many puzzles related to fundamental particles and their interactions.   it is assumed that preons are what compose quarks, leptons and gauge bosons. in this paper   we consider indirect manifestation of color octet electrons at the next generation linear colliders : international linear collider ( ilc ) and compact linear collidors ( clic ). in section 2, we present the interaction lagrangian of the leptogluons as well as signal cross - section for the process @xmath9 via t - channel@xmath0 exchange at @x Math3 tev. in sections 3 and 4   the signal and background analysis performed at ilc and clic is given. in the last section we give an interpretation of obtained results and concluding remarks.
we propose the _ dynamical generalized polynomial chaos  ( dgpc ) method for solving stochastic partial differential equations ( spdes ) driven by white noise.   the algorithm uses a restart procedure to construct polynomials of the projections of the solution at the current steps and the future random forcing, and then compresses the solution into a representation involving a finite number of random modes, i.e., a projection onto a lower dimensional manifold. in cases where the modeling equations contain non - forcing random inputs other than brownian forcing, such as a random viscosity, the karhunen  loeve ( kl ) expansion is applied to the solution and the random parameters together so that the algorithm automatically selects the intrinsic variables, which have the largest influence on the solution. since kl expansions are known to be optimal in the mean square sense, at each restart point in time, only a few dominating, most energetic, random modes are chosen and incorporated into pce to represent the future solution. however, the combination of the random kl modes with the random forcing variables brings about high dimensionality, which hinders the capability of the pc method for long - time computations.
the transition from hadron phase to strange quark phase ( sqp ) @xcite is studied within the framework of the quark mass scaling and thermodynamic treatment model, which is based on the density dependence of the effective masses of quarks derived from in - medium chiral condensates.   this model is used to study the relationship between the equation of state ( eos ) of quark matter and the maximum mass of a new born neutron star. for the first time   it is shown that the transition from hp to sqp can be achieved by introducing new degrees of freedom like hyperons, kaons or quarks accompanied or not by a phase transition. as a consequence, the eos of the nuclear matter in the center of the neutron star is reduced to @xmath0 when the mass of the remnant is below the mass threshold for quark nucleation. at high densities   the transition tosqp is forbidden, but if the mass is slowly accreting the transition is allowed the transition could be allowed.. the role of temperature or other parameters defining the initial state of aNewborn neutron star has not yet been studied.
the spectrum of electromagnetically induced transparency ( eit ) in the strongly correlated atomic systems @xcite is used as an alternative and non - destructive method to probe the quantum many - body physics.   the eit spectrum is shown to be solely determined by the single - particle green s function of the ground - state atoms, from which the observables of any single - particles, the ground state energy, and the excitation spectrum can be extracted. in this paper, we propose an experimental setup to realize the reconstruction of the single- and two - dimensional green s functions, and also discuss the finite size effect. using three - dimensional mott - insulator and one - dimensional luttinger liquid as two examples,   we investigate the reconstruction steps by measuring the frequency moments from the information of eit spectroscopy.. our results suggest a universal determination on the essential single -particle green sfunction of the ultracold quantum gases in parallel to the angle - resolved photoemission spectroscopic measurements in the solids.
the gamma - ray burst ( grb ) population from the pvo satellite is a large multiwavelength astronomical catalog of bursts with a wide range of bulk properties, including fluence, spectral hardness, and burst duration.   we perform principal components and factor analyses of nine bulk property variables using 625 grbs from the batse 3b catalog to determine whether the population of grbs is homogeneous or divided into distinct classes based on their bulk properties. for each variable, we find that the population is composed of two or three classes : short - hard and long - soft bursts, which are separated by a bimodality in the burst duration variable @xmath1 ( time within which 90% of the flux arrived ), and two types of fast - rise exponential - decay bursts with different ratios of total fluence and@xmath4300 kev fluence. while the most widely accepted taxonomy of grb bursts is the division between these two groups, we also find an anti - correlation between @x math1 and peak intensity, consistent with a cosmological time dilation, and a positive correlation between k93 and maximum fluence ; the latter may be the manifestation of a single astrophysical process
graphene is a two - dimensional graphite material that exhibits amazing properties in a plenty of fields, namely, electronics, spintronics, optics, etc.   the unusual properties of graphene are owing to its dirac - like band structure, where conduction and valence bands touch at six discrete points at the edges of the honeycomb brillouin zone. here   we investigate how coulomb blockade effects are altered by the presence of relativistic ( dirac ) fermions located at the dirac point of graphene quasiparticles. for double occupancy the dot level is shifted by an amount @xmath1 that describes the coupling between the quantum dot and the Dirac point, and the hybridization depends on energy@xmath2.    the experimental measurements show that the kondo effect can be induced by lattice vacancies in graphene sheets. besides, under certain circumstances many - body effects, such as the kondradiostructural kondo physics can be observed.
spin - charge separation and interaction dependent power laws of correlation functions have been known as non - fermi - liquid behavior of tomonaga - luttinger ( tl ) liquid, which is expected to describe the low energy physics of one dimensional ( 1d ) interacting electron systems. in this paper, we consider the resonant tunneling through double impurities in a spinful tl liquid under magnetic fields.   it is shown that the spin - charge mixing effects can clearly be seen in the resonanceant oscillation patterns of zero bias conductance in the @xmath4 plane. by applying a strong magnetic field,   the spin rotational symmetry is violated and the spin and the charge sector mix with each other, leading to the violation of spin - charges separation in the excitation spectrum. also, the resonance pattern of the conductance peaks at low temperature is deformed due to the conformation of the contour shape of the system, depending on the bulk parameters such as temperature, interaction parameters and magnetic field induced " spin - filtering ", which are explained by a renormalization group analysis of a single impurity potential.
we study the scattering of two identical blocks of mass through multiple elastic collisions with a ball of mass sandwiched by them.   we find all possible values for _ the magic mass ratios _ at which the energy and momentum of the incident block are completely transferred to the scattered block.
early hydrogen reionization is a particularly interesting process in the high redshift universe.   it is inevitably linked to the appearance of the first star forming objects, at least those that served as sources of the ionizing radiation. here   we examine how the key ingredients in this process can be probed by observations of qso spectra and future galaxy surveys. using a semi - analytic model for galaxy formation in a high resolution n - body simulation of dark matter, we estimate the amount of ionizing flux emitted by stars at high redshifts. using several schemes to follow the development of ionized regions in the simulation  , we obtain predictions for two statistics : the expected number of neutral segments longer than a given length, and the cross - correlation function between the galaxies and neutral regions. both of these measures rely on observations of quasar x - ray scattering ( qso ) spectra, and also on a sample of high red shift candidates for the sources of ionizerium from the cosmic microwave background ( cmb ). based on the results of the present study, we find that the most important ingredients in the reionisation process are the presence of high density regions of neutral hydrogen and the existence of large
the fundamental plane of quasar - like objects ( qsos ) is studied by principal components analysis on a sample of 70 archival images of low - redshift galaxies.   we find an x - ray fundamental plane for these objects that is more precise than the optical one, and it shows a relationship between the nuclear and host features that goes beyond the simple correlation of nuclear luminosity and host luminosities.
we explore the physics of two coupled nonlinear cavities in a dissipative setting where both sites are driven coherently and symmetrically.   we perform semiclassical and quantum analysis of the system investigating the complex interplay of many competing terms such as hopping, interaction, drive, dissipation and detuning. in a semiclassic treatment, we show that the nonequilibrium steady states have asymmetric number density in the two cavities along with the expected symmetry preserving states. for a full quantum treatment,   the symmetry breaking states are no longer seen, similar to the case of single - cavity bistable systems.
the landau - pomeranchuk - migdal ( lpm ) effect interpolates between the bethe - heitler and factorization limit for the radiation spectrum of a charged particle undergoing multiple, @xmath4 say, scatterings in a medium.   this effect interfers destructively if the separation between scattering centers is very large, i.e., if the scattering centers sit too close together to be resolved by the emission of the emitted photon. here  , we explore the non - abelian analogue of the lpm - effect in terms of the eikonal approximation for the radiating hard particle in the presence of an external field using a light - cone path integral formulation which describes in a coordinate - space representation the transverse momentum kicks on the eikkonal path, mimicking the motion of the particles in the medium at the same time. with respect to the x - ray diffraction data from the slac-146 experiment,   we show that the model is well suited for the qed target, where the coherence length ( formation length ) determines the longitudinal scale on which the radiated particle becomes distinguishable from its radiating parent. as expected, the
the transport of fluids through geological media such as hydrocarbon and water reservoirs involves a combination of flow through the microscopic pore space of the rock itself and flows through macroscopic channels such as fractures.   the aim of this paper is to study the permeability of single self - affine two - dimensional fractures. in the limiting cases, where the roughness associated with the fracture surface is either small or large compared to the mean aperture,   it is possible to obtain general analytic expressions that are supported by numerical simulations, using the lattice boltzmann method. in subsequent work  , we will consider the fully three dimensional case, and go on to consider more general transport processes in fractures, involving both passive tracers and finite - sized suspended particles.
microwave emission from interstellar dust grains contributes a " galactic foreground" which must be recognized and subtracted from observations of the sky in order to carry out studies of angular structure in the cosmic microwave background radiation ( cmbr ).   this microwave emission also offers us new information on the properties of interstellar Dust grains.. in  [ sec :   obs ] we review the observational evidence for infrared and microwave emission from Interstellar dust.
the nuclear gluon distribution of the quarkonium at the lhc is investigated in proton - nucleus and nucleus - nucleus collisions using the color - singlet model ( csm ) and the non - relativistic quantum chromodynamics ( nrqcd ) approach.   the results show that the production of associated @xmath8 and@xmath12 at large @x Math9 is dominated by the gluons induced hard processes in the proton, and then the quarks produced in association with a direct photon are strongly dependent on the nuclear gluminescence rate. for the latter, the contribution from the nuclear shadowing process is dominant over that from the fragmentation process which is observed in the csm at lo. the effect of the qcd corrections to the inclusive hadroproduction of @x math8 and @x maths12 at the Lhc has been investigated using the next - to - next- to - leading ( nnlo ) order qcd approach. as expected, the contributions of the nuclear shadows and the photophysics of the associated processes are found to be dominant in the larger @xMath9 region. however, the effects of the other two processes
we present a geometric approach to the calculation of the charge pumped by adiabatic quantum driving in an open quantum system.   this is based on the observation that, independent of the specific physical scenario, the pumping field @xmath3 is in fact the vector of linear response coefficients in the adiabscent expansion of the current. as a function of the driving parameters,   the equation of motion ( eom ) is used to calculate the equilibrium quantum correlation functions at fixed driving parameters under the sole assumption of weak dissipation. here   we illustrate the method using a cooper - pair sluice example and show that it can be used in a wide range of cases of experimental interest, ranging from electron pumps based on quantum dots to cooper - Pair pumps in superconducting devices.
the molecular dissociation and dissociative ionization processes of h@xmath5 @xcite are studied in detail using fragment - ion coincidence measurements.   the experiments are based on a short intense infrared pulse interacting with the molecule, at a temperature of a few hundred kelvin. for a pulse duration of 60 fs or less, the laser interaction is sudden on the rotational timescale. due to the small nuclear mass, the expansion ( vibration ) of the molecule is very rapid - on the scale of a fraction of a femtosecond.the main aim of this paper is a direct comparison of theory and experiment for the proton energy spectrum produced by a short intensity infrared pulses interacting with h@Xmath5 ; the results are in excellent agreement with the experimental data.
recent results from the searches for high - redshift type ia supernov  ( sne ia ) have been interpreted as suggesting that there is a cosmological constant and that the expansion of the universe is accelerating.   the results are robust in that they are independent of the value of the hubble parameter, @xmath4, and also of the local calibration of the sno ia luminosities. here   we examine how different the local value of @x Math4 must be from the global value in order to significantly change the cosmology derived from the fitting of high -Redshift sne ian data to the hubbles.. the results show that the best fit to the data is found to be an @x maths2 open cosmology with a shift in the local - to - global hubble ratio of ~0.5 per cent from the 95 per cent confidence limit when the data are corrected for redshift between@xmath6 and @x math7.    the recovery of critical mass density cosmologies is more difficult at greater than the 99 per cent level and requires a large ratio of > 0.9 per cent.
the formation and growth of cosmic objects is not an easy task.   even in the simple and yet most likely scenario, hereafter assumed, of structure formation via gravitational instability from a primordial gaussian random field of density fluctuations with power spectrum leading to hierarchical clustering   no exact model can be build because of the lack of an exact solution for the growth of density fluctuation in the non - linear regime.. numerical simulations are very time - consuming and give access to the yields of the complex processes taking place, but the full understanding of what is going on is not easy. here   i will focus on the improvements achieved, for the last twenty years, in the construction of a detailed model for the hierarchical clusters of objects based on the theoretical mass function of objects ( or haloes ) derived from @xmath6-body simulations. as a result  , i have developed a new model which provides us with typical times and rates of the clustering process and gives us a good fit to the observed properties of bound virialized objects.
we study the dynamic localization and quantum entanglement of two interacting electrons in a double quantum dot system driven by an ac field.   we show that with certain choice of parameters, in contrast to direct intuition, the coulomb repulsion may enhance the localization due to the level crossing associated with different symmetries of a dynamic parity operation ( discussed in more detail later).the maximally entangled bell state can be prepared and maintained with a pulse of an ac Field.
in this article we investigate numerically the disturbances caused by isolated interstitial particles and compare the results with the predictions of continuum elastic theory.   we study a two - dimensional crystal of soft particle interacting via the gaussian potential of a system of gaussian core particles at all densities @xcite using computer simulations. for certain defect configurations  , we observe an exponential rather than algebraic decay of the displacement fields of single interstitials. in this case,   the behavior can be understood in terms of a simple bead - spring model introduced in sec. here, we show that the effects of discrete lattice effects dominate on spatial scales of the order of few lattice constants.
the existence and properties of stationary states have significant importance in quantum information processing and quantum theory itself. for low - dimensional closed systems,   the stationary states can be obtained relatively easily.   an analysis of open quantum systems is much more complicated as they are a stage of a variety of physical phenomena. in this paper, we propose a method of calculating stationary states in the case of two - dimensional open quantum system using the theory of block operator matrices. to achieve this goal, we use the _ riccati operator equation _  @xcite to solve the eigenproblem for the total hamiltonian. by using the solution of the equation  , we show that the stationary state can be derived from the reduced time evolution of the open system.
superconductor - ferromagnet heterostructures with strong spin - orbit coupling ( soc ) and broken spatial inversion symmetry are promising platforms for realizing topological superconductivity.   however, there is little knowledge of how supercurrents in these systems influence the ordered spins. in this work, we consider a lattice of ferromagnetic spins in contact with a conventional superconductor / adatom system with broken spatialinversion symmetry and strong soc. using a tight - binding bogoliubov - de gennes ( bdg ) formalism to self - consistently calculate the response of the system to a supercurrent,   we find that super Currents produce a reactive spin - orbital torque on the spins and formulate a phenomenological description of the supercurrent - induced magnetization dynamics. by using a theoretical model of the current - induced spin - torque mechanism, we show that the spin - triplet correlations in the interlayer are determined by the orientation of the single - molecule supercurrent with respect to the crystallographic axes and that the sot can be estimated to be on the order of @xmath0 mt in proximitized hole - doped semiconductors, which is comparable
in the early afterglow phase of gamma - ray bursts ( grbs ), some interesting features are emerging, including a very early sharp decline ( phase - i ), a shallow decline or even plateau, and the energetic x - ray flares.   it is widely suggested that these phases may be relevant to prolonged activities of the central engine while the simultaneous optical afterglowing is dominated by grb forward shock emission. in order to test this interpretation, we calculate the polarization property of phase-i and show that strong evolution is likely. for phase - ii, we argue that similar phenomena are also expected in the decline phase of the x - rays flares and possibly in the late time part of phase - iii, especially those associated with a chromatic break in optical band.
summarypre - main sequence ( pms ) stars are surrounded by disks, and a substantial portion of their final mass is accreted from these disks.   however, the prediction that this accretion will cause the stars to rotate at close to their breakup speed is not borne out by observations. here  , we examine the early @xmath5 history of stars surrounded by or without observable disks and show that pms stars, even those without observables, evolve at nearly constant angular velocity as they evolve toward the zenith of the equator ( zams ).. this result is inconsistent with expectations that convective stars lacking disks should spin up as they contract, but paradoxically consistent with disk - locking models.
failure avoidance is of paramount importance in critical software systems.   there are a number of regulations and norms such as do-178b@xcite and do-278@xcite that define the set of safety objectives to achieve an acceptable level of safety. due to the specific requirements of the safety monitoring processes,   it is usual that the status information for all the involved processes is very complex ; information is typically contained in different places, and it is responsibility of several teams. this situation makes the status monitoring to be a difficult task to perform, prone to causing several undesirable effects such as missing information, or bad dimensioning of the development situation. here  , we present an approach to improve the current practices of monitoring by providing a new methodology that covers the verification management activities in a collaborative environment to facilitate the integration with other life cycle process, and provide the possibility of future extensions.
accretion bursts in protoplanetary disks have been observed to occur up to @xmath9  m@xmath7  yr@x maths8  @xcite over observed time - scales of 10 - 100  years.   the impact of accretion bursts on the chemical evolution of the envelope and disc has been studied previously, but the chemical consequences of these bursts have not been investigated in great detail. here   we investigate the effects of such bursts on water, and in particular its d / h  ratio, by using a model of the magnetorotational instability ( mri ) and gravitational instability ( gi ) cycle in fu orionis systems ( e.g. *????   * ; *????, we find that the accretion burst results in a significant increase in the temperature and luminosity of the interstellar medium and pre - stellar cores, resulting in the processing of a large fraction of the material from the outermost layer of the core.    this processed material is then transported to smaller radii in the disc by advection and to larger ones by turbulent diffusion. as expected, the process of water is more rapid in the case of the high
we propose an alternative way to create an effective bose - hubbard hamiltonian, which does not suffer from the limitations of individual lattice sites.   we consider two realisations of an array of micro - cavities and study the dynamics of polaritons, combined atom photon excitations, in this arrangement. since the distance between adjacent cavities is considerably larger than the optical wavelength of the resonant mode, individual cavities can be addressed. by varying the intensity of the driving laser, the nonlinearity can be tuned and hence the system can be driven through the superfluid to mott insulator transition. for each cavity,   the parameters describing the on site repulsion and inter cavity hopping are obtained by adjusting the energy of the external laser. a theoretical analysis of the feasible parameter range is presented, which is backed up by a full numerical demonstration of the transition including experimental imperfections.
unstable particles are a perfect testing ground for theories that try to unify the principle of relativity with quantum mechanics.   it was demonstrated experimentally that the decay of moving particles slows down in a good agreement with einstein s time dilation formula @xcite. however, a detailed quantum relativistic calculation in@xcite has shown that there are small corrections to this formula in the case of particles with definite momentum. in the present article   we resolve this controversy by performing a detailed calculation of the decay laws of unstable particles with narrow distributions of velocities observed from moving reference frames and find that the result of @xxcite is based on an incorrect identification of the subspace of states of the unstable particle in the full hilbert space of the system. in sections  -  we present a rigorous quantum relativist framework required for the description of decays. in particular cases of this formula relevant to stable particles with sharply defined momenta or velocalities,   the non - decay probability is considered as a property of a single particle ( nucleus ), i.e., the probability of finding this particle in its undecayed state.
a simple, compact, and practical linear quadrupole trap - time - of - flight ( lqt - tof ) device is proposed for the study of atomic and molecular ions with mass resolutions of a few 100  amu.   the device is designed to be used in experiments that require near - isotopic mass resolution for atoms and molecules with masses of less than 1  nm. by coupling the lqt to the tof apparatus through a novel radial extraction method,   good mass resolution can be achieved without the complications associated with axial ejection and orthogonal acceleration. due to the use of ion optics to enhance ion detection efficiency, long interrogation times do not need to be sacrificed for higher measurement rates, as in most commercial devices, in order to build statistics on reasonable time scales. additionally, due to its simplicity and affordability, the proposed device can be built for a small fraction of the cost of current commercial tof devices.
we show that in a set of divergence - free vector fields whose flow has a persistent bykov cycle, tangencies of the invariant manifolds of two hyperbolic saddle - foci densely occur.   we also show that the global dynamics is persistently dominated by heteroclinic tangencies and by the existence of infinitely many elliptic points coexisting with hyperbolus dynamics arising from @xmath1transversality. for the set of vector fields with a given bykhov cycle,   the tangencies are strongly connected with the cocoon bifurcations which can be detected numerically with the _ time delay function introduced by lau @xcite.
in this paper we continue the exploration of the stellar content of obscured galactic giant h  ii regions using infrared spectroscopy.   w42 is a cluster of stars in the fourth galactic quadrant at _ @xmath4 25.4, 0.2 which is not seen in visual images and is considered to be at the " near " kinematic distance ( 3.7 kpc ) from the center of the galaxy where it is located in the milky way. here   we estimate the distance, mass, and luminosity of w42 from three sets of images obtained with the f/14 tip  tilt system on the cerro tololo interamerican observatory ( ctio ) 4 m blanco telescope using the two facility imagers cirim ( 1998 data ) and osiris, the ohio state infrared imager / spectrometer ( 1999 data ). by comparison to new infrared spectral classification systems for massive stars @xcite, we find that w42 appears to be one of the most massive star forming regions in the Milky Way.
the sabat detector is a novel device designed for the detection of dangerous substances hidden deep in the bottom of the sea with significantly reduced background and provides determination of the density distribution of the dangerous substance in the tested object.   the device uses neutron activation analysis ( naa ) technique and special guides for neutrons and emitted gamma rays which are used to provide non - intrusive detection of explosives or drugs. in order to optimize the dimensions and relative positions of detectors and guides we have developed dedicated open source software package written in the c++ programming language  . this simulation tool is using novel methods of geometry definition and particle tracking and the open mpi library supporting parallel computing. in this article   we present status of the design of the Sabat detector based on monte carlo simulations, focusing on the impact of the usage of neutron and gamma quanta guides.
the last year was an amazing year in neutrino physics.   it is completely clear that recent neutrinos oscillation data had big impact on theory, and it will continue to do so. here   i will remind you about the ongoing impact, and then i will list measurements that will have critical impact on theoretical in the future.
we present a quantitative analysis of the dynamics of a collaborative tagging system, using experimental data from one of the largest and most popular collaborative tagging systems, _   del.icio.us_.   we show that, choosing the right projection and the right weighting procedure, we can produce a weighted undirected network of resources from the full tri - partite folksonomy network, which embeds a meaningful social classification of resources. in this study, we adopt a resource - centric view of the system, that is we investigate the emergent correspondence between a given resource and the tags that all users associate with it. based on that, we set up an experiment using actual data from _ del.iso.us  and we build a weighted network of Resources. in section    we demonstrate that spectral methods from complex networks theory can be used to detect clusters of resources in the above network and we characterize those clusters in terms of user tags, exposing semantics. finally, section  ( sec : conclusions ) gives an overview of our results and points to directions for future work.
we investigate theoretically another kind of electric - field driven edge spin - accumulation which might occur in a thin strip of a two - dimensional electronic ( electron or hole ) system.   this phenomenon is essentially a _ kinetic magnetoelectric effect__@xcite due to boundary - confinement induced spin - orbit coupling ( which will be called _ edge so coupling _ below ), but very interestingly, it would manifest in a very similar manner as was conceived in an spin hall effect. from the theoretical points of view,   such a phenomenon would be useful in the context of semiconductor spin - based electronics ( _ spintronics _ ) because it might provide an effective way for generating spin currents and/or non - equilibrium spin density in a nonmagnetic semiconductors without use of ferromagnetic metals or ferromagnetics.
deep neural networks ( dnns ) have been receiving ubiquitous success in wide applications, ranging from computer vision to speech recognition.   as the sizes of data mount up, people usually have to increase the number of parameters in dnn so as to absorb the vast volume of supervision. with different intuitions,   there are mainly two types of dnn compression methods, which could be used in conjunction for better parameter savings : the first type tries to revise the training target into more informative supervision using _   dark knowledge_. in specific, hinton suggested to train a large network ahead, and distill a much smaller model on a combination of the original labels and the soft - output by the large net. while the second type observes the redundancy existence in network weights, and exploits techniques to constrain or reduce theNumber of free - parameters in Dnns during learning. here  , we propose an approach to relieve this instability, still in a two - phase style for preserving efficiency. at first, we use hashednets to efficiently implement parameter sharing prior to learning, and show notable compression with much less loss of accuracy than low - rank decomposition. after revisiting its mechanism, we conjecture this instability comes from at
strong gravitational lensing is a powerful probe of the large scale properties of the universe.   we report the discovery of a gravitationally lensed quasar, sdss j133222.62 + 034739.9 ( hereafter sdssj1332 + 034 ), from the sloan digital sky survey quasar lens search ( sqls ; *?????   * ). in this paper  , we describe the selection of the quasar and its selection function from the sdss quasar sample for lensed qasars statistics. using the same selection algorithm as that used in @xcite, we find that the best fit to the sqls data is based on the presence of a low - redshift early - type galaxy with a diameter of about 1.5 cm.    the cosmological model we use to model the lens shows that the density of the galaxy has a strong gravitational effect on the size of the lens, which is consistent with the results of our previous studies.
the existence of a supermassive black hole at the galactic center has been a source of continuous debate in the literature.   the main motivation for this hypothesis is that it would emit less x - rays and gamma - rays than a compact dark matter object, behaving basically like a scaled - down active galactic nucleus. however, although earlier observations have shown that the central region of the galaxy actually does emit x - ray and Gamma - rays, the supposed true center, usually assumed to be sgr a@xmath7, does not emit strongly, at least up to energies of 30 kev. here  , we review the current state of knowledge on the nature of the dark mass distribution at the centers of active galaxies and discuss the role of relativistic accreting matter in the formation of the so - called advection dominated model of the core of the galactic centre.    we find that the rate of accretion of matter onto the black hole is much lower than that expected for a black hole of the size @xmath11 @x Math10, and we propose a new model which accounts for this low activity level by assuming that the blackhole is a very small particle - rich black hole with a
we propose a novel algebraic model for the electrical behavior of the rf modulated plasma boundary sheath.   our investigation is motivated by a critical assessment of the pioneering ( and still " classical " ) algebraic sheath models which were proposed by lieberman twenty - five years ago @xcite. in many aspects,   the approach is similar to that of the original model, but we endeavor, however, to correct the three fundamental weaknesses of the lieberman models, namely that they are limited to the case of a single driving frequency, to the regime of large applied voltages, and to the two limiting cases of either highly collisional or completely collision - free motion. in other words, our goal is an algebraicmodel which captures the plasma sheath behavior in a wide range of frequencies, waveforms, amplitudes, and collisionality.
the search of 3d data cubes is not a straightforward task.   it is non - trivial to design a source - finding algorithm which is flux - limited, and complex, spurious structures can be difficult to automatically distinguish from astronomical sources. while visual inspection of the data can, through the extremely powerful capabilities of human pattern recognition, often overcome the problem of distinguishing real from spurious sources, it suffers from being subjective. in this article   i present a benchmark table of the performance of a new viewer for searching 3d neutral hydrogen data cubes using blender, which is designed from the ground up as a blender - based viewer for fits data cubes. by default,   the user can load the data into three different projections of the cube, and then render the images using blender s internal raytracing engine. when switching from one projection to another, the results are compared with those of frelled, a previous version of blender that was designed to load fits data into a program never designed with astronomers in mind. at 3 minutes per frame, a 10 second animation ( at standard 25 f.p.s. )   would take 12.5 hours to render, while a 500@xmath3500 pixel image (
we study the possibility to detect supersymmetry ( susy ) and lepton flavour violation using the @xmath0 and@xmath1 signatures at the level of full detector simulation for the minimal supergravity model ( msugra ).   the results show that the signature with two opposite charge and the same flavour leptons is a good candidate for the discovery of susy at the large hadron collider ( lhc ), but the number of lepton events depends rather strongly on the relations among gaugino and higgsino masses and in some modifications of the compact muon solenoid ( cms ) test point lm1 with arbitrary relations among these masses the detection of the susy signature is not possible.
the neutron lifetime @xmath1 is an important parameter in tests of the standard model of particle physics.   the current particle data group ( pdg ) average is 880.1@xmath2 1.1 s @xcite, but the actual uncertainty of this parameter may be of the order of 2 seconds or more. as a possible way of advancing this field, storage of polarized ultracold neutrons ( ucns ) in a magnetic trap has been pioneered by paul _   _ @xaite and is currently being pursued vigorously by several groups worldwide.    however, the potential loss due to depolarization, defined as spin flip relative to the local field direction, is commonly assumed to be negligible. for systems using permanent magnets the question of gradual demagnetization over time appears to have found little attention so far. here   we use a simplified model of magnetic field distribution to include arbitrary ucn motion with both vertical and horizontal velocity components, confined to the vertical space between upper and lower turning points that depend only on the ucn energy for vertical motion. in our model the magnetic field magnitude @x Math8 is uniform within any horizontal plane, so there is no horizontal component
the density matrix renormalization group ( dmrg ) is a powerful method for low dimensional interacting systems.   it has been applied to a great variety of systems and problems including, among others, spin chains and ladders, fermionic and bosonic systems, disordered models, impurities and molecules and 2d electrons in high magnetic fields. in this article   we will attempt to cover the different areas where it have been applied without entering into details but in a few cases, where we have chosen some representative contributions.
we present a detailed calculation of the @xmath1 coupling contribution to the rare decay@xmath15.   the current experimental limit on this decay mode @xcite will then be used to constrain the coefficients of this neutral gauge boson self coupling. in this way   we find that the bounds obtained in this manner rely on very few assumptions, though they are weaker than the ones obtained from the analysis of the same data at lep-2 @xaite.
the optical time domain reflectometry ( otdr ) and frequency domain reflectometer ( ofdr ) techniques for optical fiber characterization have been a point of major focus since the late seventies when barnosky and others demonstrated that, by measuring the rayleigh backscattered signal from a pulse sent into the optical fiber, one could extract its physical properties such as attenuation coefficient and eventual power losses along its length.   however, embedding any of these techniques in passive optical networks ( pon ) systems remains a challenge in terms of technology and cost - effectiveness not to mention the in - service monitoring paradigm @xcite. in this paper  , we present a new method for fiber monitoring in the low - frequency range, up to a few hundred kilohertz, where the @xmath0 hindering effect is not too harsh.    instead of taking the fourier transform of the acquired signal, we attempt to fit the resulting backscattering signal with its associated mathematical model, which, in order to simplify its description, we model as a function of the transmitted light signal s spatial resolution and the wavelength of the optical sub - carrier at which it is detected. using this model, we show that the
we report an upper limit for the muon neutrino mass obtained by measuring the radii of curvature of the pion and muon tracks of an event, in which a pion decays into a muon and a muons neutrinos, recorded during the runs of the ps 179 experiment at the beam of antiprotons of lear at cern.   the experiment was designed and built for the study of the interaction of antiproton interactions with light and medium - light nuclei at the lear facility of cern using a self - shunted streamer chamber placed in a magnetic field ( @xmath59b / b = 10@xmath60 ). from the two vertices of the pairwise decays,   three neutrines are emitted : from the first a muoneutrino and from the second an electron neutrinino and amuon antineutrini.the results obtained provide information on the fundamental nucleon - antinucleon forces and on the distribution of nuclear matter, as well as on the properties of highly excited nuclear matter.
aerosol particle size distributions are increasingly being measured on a regular basis, with the potential to provide more detailed information than measurements of particle mass concentrations such as pm10 or pm2.5, traditionally used for regulatory purposes. in this paper   we explore three different informative priors for estimation of mixtures where the data are highly correlated, and all parameters in the mixture are allowed to vary.   the results show that the choice of informative prior is important for the interpretation of the simulated data, both in terms of interpretability of the mixture components and weights ( e.g., the number and change in size of particles for each mode ) and for the ability to measure the variation of the parameters of the components over time.
we propose explicit tamed euler schemes to numerically solve stochastic differential equations ( sdes ) with random coefficients driven by lvy noise.   the taming techniques developed here allow one to approximate these sdes with drift coefficients that grow super - linearly. by adopting the approach of @xcite  , we prove strong convergence in ( uniform ) @xmath0 sense of these tamed schemes by assuming one - sided local lipschitz condition on drift and local lips chitz conditions on both diffusion and jump coefficients for the case of sdes which have non - random coefficients. as an application of our approach which considers random coefficients, we also present in this article uniform @x math0 convergence results of explicit tame euler scheme for the cases of sddes with non - linear coefficients.
many adsorption systems exhibit either complete wetting below the triple point or triple point wetting transitions.   these behaviors are recognized to arise from strongly attracting substrate potentials and/or small mismatch of substrate / adsorbate lattice constants @xcite. in 1991, cheng   cheng ( ccst ) posited a simple model which interprets the transitions in terms of a balance between the surface tension cost of producing a thicker film and the energy gain associated with the film s interaction with the surface, v(z )@xcite. in this paper, we extend the simulation studies to a larger family of systems for which the hypothesis is relevant. using this model, we present detailed results for several systems which yield fairly distinct adsorbed behaviors.  one of the most striking is the improved agreement for @xmath12he contact angle and wetting temperature on cs, the most studied wetting transition to date @xficite.
we investigate the behavior of the electromagnetic field in the background of a non - charged cosmic string.   we find the retarded green function and show that the field propagates along null geodesics ( on the light cone of the source ) and is scattered on the curvature of the string. for a single straight thin cosmic string,   the field is self - interacting : a monopole charge is repelled from the string by its own field, a dipole is forced to align the string, and a magnetic field of the current flowing along the line parallel with the string is drawn along the stream of current.
the origin of cosmic rays still remains an unanswered fundamental research question.   the galactic magnetic field is a key factor in the search for cosmic ray sources, and it is strong enough to displace original arrival directions of protons with energy @xmath6  eev by several degrees from their original arrived directions outside the galaxy..in this work we investigate whether cosmic ray deflections in the Galactic magnetic field can be reliably corrected for, given the current knowledge of the field. based on the two galactic field parameterizations pt11 and jf12, we find that the distributions of cosmic ray angular deflections depend strongly on their arrival direction, charge and energy, and that the rigidity dependencies of these distributions are sufficiently strong to limit the extent to which cosmic ray Deflection can be controlled in terms of probability distributions. using the different results of the two parameters as a measure of our current understanding of the galactic field, we propose a minimum rigidity threshold above which cosmicray deflection may be controlled.    we compare the cosmic rayangular deflection distributions in the two parameterizations and study differences in the dispersion of arrival distributions. finally, we study the practical consequences of galactic field corrections and their uncertainties by performing
supernovae ( sne ) are dramatic and violent end - points of stellar evolution, and lie at the heart of some of the most important problems of modern astronomy.   they are involved in the formation of neutron stars, black holes, and gamma - ray bursts ( grbs ), and are sources of gravitational waves and of neutrino emission, and candidate sites for high - energy cosmic ray acceleration. to understand the mechanism that is responsible for the accelerating expansion of the universe, we have developed a new method to measure the rate of core collapse - induced explosion of short - lived massive stars ( cc sn ) in the local universe at low redshift and at high redshift using the time - resolved sn spectroscopy technique. by comparing the sn rates of cc sne with those of long - lived low mass stars ( sne ia ) and plateau cc sne ( sne iip ) at different stages of their photometric evolution, we show that the cc sn rate is significantly faster than the type ia sn rate at both low and high redshifts. however, the difference between the two types of sn rates is due to the different chemical and physical properties of the sn progenitor stars. as a result,
electrostatic interactions of charged macromolecules and colloids are often governed by small oppositely charged ions ( counterions ) that maintain global electroneutrality.   these counterion - mediated interactions play a fundamental role in classical charged ( coulomb ) fluids that are abundant in biological and soft matter context @xcite and affect their functional, structural and dynamical behavior. however, there is no general method that would allow for an accurate prediction of electrostatic effects in all regions of the parameter space, defined by the surface charge density of macroions, charge valency of counterions, dielectric mismatches between the often hydrophobic core of themacromolecule and the surrounding aqueous medium, etc. here   we present a new approach to the systematization of non - poisson - boltzmann electrostatic interactions in charged macroscopically active systems based on the notion of weak coupling ( wc ) and strong coupling ( sc ) approximations.we show that the wc approximation is more accurate than the sc approximation in characterizing the electrostatic interaction of mobile counterions with fixed external charges in the system when compared with direct electro static interactions between the counterions
@xmath0ar and @xmath3kr are two radioactive nuclides that are present in abundant quantities in liquid argon, and their presence can limit the sensitivity of experiments looking for low energy rare events ( wimp dark matter interactions, neutrinoless double beta decay ) using liquid argan as a target or as a shielding material.   the precise determination of the intrinsic specific activity of @x Math0ar is therefore of significant interest for the design of wimpdark matter detectors employing argon as an experimental target. here   we report the results of a two - phase argon drift chamber experiment to determine the @x math0ar specific activity in natural argon at the argon boiling point ( 86.7k ) and the atmospheric pressure of the gran sasso laboratory ( about 950 mbar )  @xcite. by analyzing the scintillation light emitted by the photomultipler tubes ( pmts ) located in the gas phase and facing the liquid volume below, we show that the total @x maths0ar activity above 100  kev is 0.2  bq / pmt, dominated by the @Xmath9th and #10u chains
non - renewal firing statistics of neuronal activity is often described as a renewal point process, or even a poisson process.   however, in some sets of experimental data correlations are observed between consecutive interspike intervals ( isi ), @xcite, which do not conform to the renewal hypothesis. in principle, any sort of memory in the neuronal firing mechanism could bring about memory into the sequence of isis, thus disrupting a possibility for it to be renewal. in this paper, we study here the simplest possible case of a network  a single neuron with delayed feedback. under those conditions,   we prove rigorously that statistics of its isi statistics can not be represented as a markov chain of any finite order.
the andreev - type transport through the double quantum dot ( dqd ) nanostructure coupled between the normal ( n ) and superconducting ( s ) leads is studied experimentally.   we focus on the subgap regime, i.e.  energies considerably smaller than the pairing gap of superconductor. under such conditions eigenstates of the uncorrelated quantum dots   are represented either by the singly occupied states or by coherent superpositions of the empty and doubly occupied configurations. to highlight this sort of emerging physics we shall explore in more detail the interference patterns originating from a charge leakage between the central quantum dot  and another side - attached one ( qd @xmath10 ).    we also analyze stability of these patterns with respect to a decoherence induced by coupling @x Math11 to the floating lead ( d ) as sketched in figure.
the quantum mechanical motion of electrons in two - dimensional space, subject to crossed magnetic and electric fields and in the presence of a single impurity described by a zero - range potential, provides a basis for the explanation of the integer quantum hall effect @xcite. until now in all considerations   the electric field has been treated as a small perturbation.the purpose of the present work is to reconsider these investigations and to discuss some novel phenomena which appear for nonperturbative electric fields.
we have analyzed the two - dimensional spectra of the galaxy iizw70, a low - metallicity hii galaxy that was observed with the integral field unit ( ifu ) spectrograph at the cosmic microwave array ( pmas ) at caha, using the software fit3d @xcite.   we derive the chemical and physical properties of the external ionized gas component of this galaxy, which is located at more or less one kpc away from the main body of the galaxies. in particular, we study the chemical abundance distribution of the ionization due to star formation and active galactic nuclei ( agns ), which are separated from the interstellar medium by a chain of individual star - forming knots that cross the whole optical body of its main body. for each fiber, we find that the fluxes of the emission lines @xmath05007/h@x Math8 vs. @ xmath96717,31/h+@x math2 and @x maths96584/h=30@xMath11 ] are about 1.5 kpc higher than those of @Xmath
the first - year data from the wilkinson microwave anisotropy probe ( wmap ) have been used as a basis for testing cosmological scenarios, substantial improving of evaluation accuracy of basic cosmology parameters related to the geometry of our universe, dynamics of its expansion, matter and energy contents.   the aim of this paper is to understand the physical meaning of structures within wmap measurements in order to detect or limit possible non - cosmologically influencing factors affecting the data used for determining cosmologic parameters. using two simple analytical methods to study possible foreground or observational effects in the wmap first-year data, not recognized and/or p removed by the cleaning methods used by the w map team, we show that the scanning effects present in the raw signal data can leave clear imprints on the gradients maps from all frequency channels, retained even in coadded, smoothed, and interleaved maps. then, we investigate distribution of signal dispersion in the Wmap maps to find a significant asymmetry between the northern and southern galactic hemispheres. following some previous authors, we argue that a natural explanation of this asymmetry is residual galactic contamination. finally, the inevitable influence of the above -
in this contribution we discuss a model for noncommutative quantum mechanics ( ncqm ) where non commutativity in the phase space is considered in the context of the gravitational quantum well ( gqw ) @xcite.   we consider the dependence of the energy spectrum of the gqW on the mass of the particles in order to study the quantum to classical transition from the non - relativistic state to the classical state.
giant molecular clouds ( gmcs ) are observed to have velocity gradients that many authors have interpreted as being caused by rotation.   however, simple formation theories that assume giant molecular clouds form by condensing out of the galactic disk are at odds with some of the observations. in this paper  , we shed light on the angular momentum problem by doing a detailed analysis of the kinematics in gmrs and the surrounding interstellar medium ( ism ). whereas previous studies estimated the initial angular momentum imparted to gmms from the galactic rotation curve ( e.g., blitz 1990 ; blitz 1993 ), we compare the velocity fields of gmrcs to those of the ism with which they are associated directly from observation. using first - moment maps of the molecular clouds in our sample and of the atomic gas surrounding them, we find that the gmcs have a spatial and kinematic correlation with high - surface density atomic gas (   ). in light of these results, we ask the question : does the rotation of the large - scale @xmath0  associated with Gmcs mirror that of the gmccs themselves?   we show that
the broadband x - ray spectra of mrk  421 ( r.a.   =  11h04m27.3s, dec  =  + 38d12m32 ;   @xmath6  = 0.031 ), a nearby and bright blazar, are one of the most comprehensively studied bl lac ( hbl ) objects in the extragalactic range @xcite. here   we report the first ever complete coverage of the@xmath4-ray continuum of the source in its low - activity / quiescence state @xcide.    the results show that the synchrotron emission of the jet itself is the dominant source of the high - energy tail of the electron energy distribution, while the low - energy component is dominated by the thermal emissions of circumnuclear gas and dust from the source via inverse comptonization of soft photon fields. using a combination of single - photon and multi - photon measurements, we find that the output of the Source in the hard x - rays range may be dominated by both the low- and the highest - energy emission components, with the latter being more highly variable than the former. on the other
the interplay of electron - phonon interactions in strongly correlated systems, such as the holstein - hubbard model@xcite, has been studied using the dynamical mean field theory ( dmft ).   the results are discussed in the context of the recently published phase diagram of the half filled holstein-hubbard model for the mott transition in the full fermi liquid fullerides @xcite which is used to study the effects of strong local electron - electron interactions on the electronic behaviour of the lattice. within the framework of the dm ft,   we show that the properties of this model depend on both the electron density at site and the phonon frequency at the locus of the monte carlo/mott transition, and that the effect of the phonons is independent of the interaction between the electrons and the dispersionless local einstein phonons. by combining the two terms  , we find that the solvation energy of the metallic phase is a function of the number of phonons in the region of interest and the temperature dependence of the magnetization potential. however, the influence of the individual phonons on the magnetic properties of the gapped phases is not
ion pressure anisotropies are ubiquitous in heliospheric and astrophysical plasmas.   the magnetic moment of ions, @xmath4, is an adiabatic invariant in the absence of coulomb collisions, making it a good model for the growth of ion - scale velocity space instabilities in the presence of magnetic field amplification. here  , we show that the mirror and ion - cyclotron instabilities can be excited in the nonlinear regime when the magnetic field is amplified by order unity or more, where the conditions typically assumed in linear studies are not necessarily satisfied. to test this hypothesis, we investigate the effects of pitch - angle scattering and magnetic moment conservation on the growth rate of the mirror instability and the ion -cyclotron instability in low - luminosity accretion disks around compact objects, such as @xcite, the intracluster medium ( icm ), and the heliosphere. using a quasi - linear analysis of the dynamics of the two types of instabilities, we find that both of them saturate after the initial phase of exponential growth with respect to the local magnetic field. however, the dominant mirror instability grows at a faster rate than the
the classical limit of the quantum results obtained from the quantum state metric in hilbert spaces and the universality of the action of the translational group in every hilber space is discussed.   the non locality of fundamental interactions in quantum physics implied by this approach, as shown physically by the aharonov - bohm effect @xcite and its generalizations@xcite, is also studied.
the multiple - scattering ( ms ) method has been recently extended to systems with semi - infinite waveguides ; here, the fields on a transverse section of each waveguide, sufficiently distant from discontinuities ( junction, bend etc. ), are matched to a linear combination of the waveguide eigenstates. as demonstrated in   @xcite, this technique is very general and applicable also to the problems which can not be dealt by the other above - mentioned methods.   the approach outlined below consists solely in postprocessing the results obtained by the ` pure'ms method. while admittedly less general than the other techniques, it is nevertheless applicable to a number of situations frequently encountered in practice, including the design of the precise shape of the beam splitter outlet that would allow maximization of the power transmitted into free space for a single waveguide terminated at the surface of a semi - finite photonic crystal.
the x - ray pulsar gx  1 + 4 is the only confirmed neutron star in a symbiotic binary @xcite which appears to be accreting from the giant companion's stellar wind.   it is also the only one with sharp dips in the mean pulse profiles of all but one of the observations, which are likely to be signatures of eclipses of the emitting region by the accretion column. during 1996   july the countrate dropped to @xmath8 @xmath9  over @x Math10  h. this dip was followed by a steady increase in the measured optical depth and a sharp decrease in the observed pulse profiles. at the phase of closest alignment,   photons emitted from the polar cap must propagate a greater distance through the column to escape and ultimately reach the observer.
the origin of the top mass of the order of the electroweak symmetry breaking ( ewsb ) scale is a central mystery of the standard model ( sm ).   the top quark condensate, which is often called the " top mode standard model " ( tmsm ), is expected to be the most attractive channel ( mac ) even including all of the bulk sm gauge interactions. in this paper, we show that the top condensation is not the mac, but the top - condenate, i.e., the one with the highest binding strength at the scale @xmath11 satisfying the critical binding strength for the top and bottom condensates, or the top- and bottom - mac, respectively. by taking into account the effect of the strong bulk electroweak interaction, we find that the theoretical top mass should be about 10%30% larger than the experimental value, even if we take @x Math11 to the planck or the gut scale.
optimization of the precoders and filters at the base transceiver station ( bts ) and mobile is a key step in the development of mobile broadband wireless networks.   we present a joint optimization scheme for the precoder and receiver filters in a time - division duplex ( tdd ) network that uses spatial precoding at the transmitters and filtering at receivers to adapt to the variations of the multiple - input multiple - output ( mimo ) channel and interference conditions by optimizing a metric such as the sum rate, signal - to - interference - and - noise ratio ( sinr ), or mean squared error ( mse ). using a bi - directional training scheme  , we show that alternating optimization of the pre - cancellation and interference pre - cancelling at the bts and mobiles leads to near - optimal performance for the optimally optimized filters for each direction when the uplink and downlink power constraints and noise power are similar. with this constraint, we consider a simplified scheme in which the satellite receive filters are also used as downlink ( uplink ) precode and the estimated mobile receiver filters precode both the downlink data and pilots. with sufficient training, the estimated filters approach the corresponding
reversibility is a fundamental property of hamiltonian systems.   we examine reversible integration algorithms ( ) for symplectic systems of the form h(,)=^2+u ( ) , which are commonly used as tools for the numerical solution of motion in a conservative potential. here  , we show that these algorithms can also be used to solve the differential equation for hamiltonians with kam tori, i.e., systems where the equations of motion are =, = -u, or < -u.    we compare the performance of two general symplectic integration algorithms, the leapfrog and verlet algorithms, and the symplectic implicit runge - kutta algorithm, for solving hamiltonia systems with respect to their reversibility. using time - reversal symmetry as a model system, we find that the speedup of the verlet algorithm is reduced by about 10 orders of magnitude when it is applied to a reversible system, whereas the jumpfrog algorithm is faster and more accurate when it uses the second - order of the symplective runge-kutta method. on the other hand, the timestep algorithm is slower and more
radio frequency ( srf ) cavities will be used in the international linear collider ( ilc ) to explore electron - positron collisions in high energy physics research.   it is necessary to build @xmath2 nb cavities with electrodynamic properties approaching the intrinsic limit dictated by theory. despite the maturity of material fabrication techniques and improvement of chemical and physical surface treatments and annealing processes in the past several years, it is still challenging to fabricate so many state - of - the - art nb cavity surfaces without performance - limiting defects. in this work, we demonstrate that a magnetic write head probe can develop a nonlinear meissner effect signal from several kinds of superconductors such as mgb@xmath4 and tl@x Math4ba@x maths4cacu@x math4o@xMath5 ( tbcco ). due to its nonlinear response  , harmonics of the drive signal are created, and these couple back into the loop probe and are measured at room temperature with a spectrum analyzer.
virus particles ( virions ) come in a variety of sizes and shapes.   however, approximately spherical shapes with diameters in the range between @xmath1 and @x Math2 are especially common. to this author s knowledge, the only discussion of these vibrational modes in the literature is that of babincov _ et al. for a spherical virus particle, which contains genetic material, rna or dna, surrounded by a protein coat ( capsid ),   the lowest vibrational frequency is estimated to be of the order of a characteristic speed of sound divided by the size of the virus particle. for the purpose of giving a more accurate estimate, we examine two models, which treat the particle ( 1 ) as a liquid drop and ( 2 ) as an elastic sphere. both models yield estimates for the lowest vibration frequency which differ by only about one order of magnitude.
the community has bifurcated in two schools of thought.   the first school rests on the conceptual backbone of conventional bcs theory and has been quite successful in addressing the physics of the fully developed superconducting state@xmath0, while the other school refers to the growing body of empirical and theoretical evidence suggesting that the electrons have been eaten by dynamical stripes@xcite. here   we want to pose the following question : can it be that stripes and nodal fermions are two manifestations of an underlying unity while they appear as dissimilar because of flawed hidden assumptions in the theory?   this is a modest attempt to make the mind susceptible to the possibility that a positive answer exists for this question.
we study vortex tubes in the velocity field of grid turbulence with a range of the reynolds number re@xmath3.   we carried out simultaneous measurements of the streamwise and transverse velocities in the mean - flow direction in two wind tunnels of meteorological research institute of india, using a hot - wire probe suspended in the flow. for laboratory experiments,   a flow downstream of a turbulence - generating grid is preferable.. this grid turbulence is isotropic and free from external influences such as mean shear, and hence is suited to isolating effects of vortex tubes at each of the scales. by using a conditional averaging technique, we extract typical intermittency patterns from the data that are consistent with velocity profiles expected for a model vortex tube. also, statistics of velocity increments are used to study the energetical importance of Vortex tubes as a function of the scale.
we give a detailed analysis of deterministic and randomized algorithms that enumerate any number of irreducible polynomials of degree @xmath0 over a finite field and/or their roots in the extension field in quasilinear time.   our algorithm is based on an improved algorithm for enumerating all the lyndon words of length @x Math0 in linear preprocessing and delay time and the well known reduction of lyndons to irreduceible poynomials. in the next subsection  , we define the word and present the result of the improved algorithm.
the edegb (  einstein - frame " degb ) gravity theory is a natural higher - curvature generalization of the einstein gravity.   it includes the e Einstein - hilbert action as the first lovelock term, and the second term is known as the gauss - bonnet ( gb ) term. in the context of the string theory,   the egb gravity has been argued to be an effective field theory with quantum corrections in @xcite. however, the gb term is indeed found as higher - order correction in string theories. in this paper, we analyze the relation between the black holes in the Edegb and the degb gravity theories from the viewpoint of einstein s equivalence principle in @xicite.
we present optical and radio observations of an afterglow from a @xmath7-ray burst ( grb ) that would have been classified dark had it not been for rapid and deep searches by the hete - ii satellite and the palomar 48-in oschin schmidt imager.   the afterglowing source was detected by the dual - band macho imager mounted on the robotic 50-in telescope at the mount stromlo observatory ( mso ), and by the wide - field imager on the 40-in telescopes at siding spring observator ( sso ) and the twin jacobs camera ( jcam ) mounted at the east arm focus of the Palomar 200-in Telescope. in both cases,   we were unable to identify a transient source within the error box due to a failure to image quickly and/or deeply enough. however, with the help of the inter - planetary network, we identified a fading source which was not present in the digitized sky survey, and which was observed two nights later using the jcam camera. based on the location of the fading source, we propose that the event was likely to have occurred in the
the gathak - sherrington ( gs ) model @xcite, which is similar to the blume capel ( bc ) model except that it has the spins couplings given as random gaussian variables, shows naturally inverse freezing in a phase diagram temperature  versus  the chemical potential.   the previous discussion suggests that the presence of non - trivial form of randomness, which means frustration,@xcite would be the essential ingredient which allows inverse freezing with no need of entropic advantage. here  , we investigate what is the actual role of frustration as a basic condition to produce naturally inverse freeze in the gs model by comparing two distinct situations, the trivial randomness and the highly frustrated regime and also studying how natural inverse freezing would be affected when the level of frustration is varied.
the commensurate magnetic excitations ( mes ) in the n - type cuprates@xcite are investigated by inelastic neutron scattering ( ins ).   the commensurability is characterized by the strongest intensity peaked at @xmath3, which covers for a wide low - energy region near the optimal doped nccoyamada - prl03 and plcco@excite.    the commenurate mes are also found in the state without long - range antiferromagnetic ( afm ) order, where the afm phase extends over a much wider range of doping and even coexists with superconductivity ( sc ) in both the electron doped and hole doped cuprate@xaite. using a slave - boson mean - field approach,   we show that the commesurate mes in the high-@xmath1-temperature superconductors are closely related to the strength of effective @x Math6-scattering.. the commersurability can be explained by a strong momentum independent ( or weakly dependent ) coulomb repulsion with form of @x math6@xcites, which is more likely originated from
the continuous electron beam accelerator facility ( cebaf ) at jefferson lab ( jlab ) delivers a highly polarized electron beam in the 1  11  gev energy range for currents up to @xmath2 200 @xmath1a.   a key part of the jlab physics program consists of high - precision parity violating electron scattering experiments that require a fast and precise electron beam polarization measurement. here   we report the construction of a new compton back - scattering polarimeter with an optical cavity at the continuous electron beams accelerator facility, hall a of jlab, which uses a low - wavelength infrared ( 1064  nm ) laser as its photon source and a high - finesse optical cavity to enhance the laser power beyond commercially available lasers to provide sufficient electron - photon collision luminosity. using this new polarimeter, we have obtained a statistical and systematic precision of 4.6% and 2.0% respectively on the parity violating electrons and photons measured by the prex + the lead radius experiment ( prex ) at jlab @xcite using a combination of single - photon and double - photon polarization measurements. because of the relatively low - current and low - energy nature of the c
the batse gamma - ray burst catalog ( @xcite ) is a powerful tool for the study of gamma -ray bursts.   it has been used for more than 20 years to collect data from the cosmic microwave spectrum ( sgr ), and is now being used to study the effects of solar radiation on the universe. in this paper   we focus on the possible contamination of the batse data with signals that are similar to those of the distant sgr signals. using a monte - carlo simulation we select 22 bursts with unusually high harmonic power above @xmath14 and show the sky distribution of the selected trigger subgroups by comparing the maximum value in the power spectrum of each mc signal with the real signal s maximum value. among the selected subgroups,   only 3 bursts show a dipole moment with a significance larger than the 22 triggers dipole : the direction of the dipole is not correlated with the supergalactic plane, and interestingly the dipoles are only away from the cmb dipole s temperature minimum.
the study of the equilibrium and nonequilibrium properties of trapped atomic gases at low temperatures has become an important topic in the condensed matter physics of the last two decades.   this is mainly due to the discovery of bose - einstein condensation, which is the only phase transition that occurs also in the absense of interactions and is, therefore, the textbook example for the use of statistical - physics methods. here   we show that quantum field theory is also very convenient for obtaining a detailed understanding of these properties by taking into account the effects of the dynamical properties of the trapped atomic gas.
we present a new method for solving the one lane moderately congested traffic flow problem.   the method is based on two lagrangian transformations, one of which is a generalization of the continuity equation of continuity ( lwrp ) and the other a newtonian equation of newtonia, formulated by payne @xcite and gerald whitham in 1955. here   we show that these two equations can be solved explicitly using the same coordinate methods from the first part of this paper @xcitesite@xcite. to make the problem more parametric we introduce dimensionless variables and solve for them by replacing the main continuity equation with the newtonic equation. as a result  , we find that both equations are solvable in parametric form.
superradiation ( sr ) is the cooperative radiation arising in a medium that contains a population inversion of excited states.   originally this effect has been stated for purely quantum systems : i.e.  two - level atoms  . experiments have confirmed this prediction, and that the phasing effect  the spontaneous origin and strengthening of correlations of originally independent subsystems  underlies it. here   we review the classical model of sr, where atoms are substituted by lorenz oscillators and the electromagnetic field is described by the classical maxwell equations. using the theory of non - uniform broadening of spectral lines for lasers  , we show that sr arrises from a competition between the ordering of phases of atoms and the disorder of the dipole - dipole interactions among atoms. according to earnshaw s theorem,   a system of point dipoles can not maintain a stable static equilibrium configuration, and hence supramolecular interactions cause chaotic behavior that disorders their phases, and therefore suppresses sr.
tidal stripping is a fundamental problem in understanding the evolution of galaxy clusters and their constituent galaxies.   it is generally accepted that tidal stripping will remove the more loosely bound stars in the outer envelopes of galaxies, but the efficiency of tidal stripping is not well understood because of uncertainties in the velocities, the mean tidal field, the distribution of dark matter, and the orbits of stars in these envelopes. here   we show that novae can be used as an independent measure of the amount and origin of the intergalactic medium ( icl ) in the central 30 square of the fornax cluster. using data from the most complete nova survey ever undertaken, we find that the rate of novae per unit mass is significantly higher in the bulge - dominated galaxy @xcite than in the disk - dominant galaxy @xmath5.    our results suggest that the majority of the icl in the cluster is likely to be due to stellar tidal debris.
the forest is a collection of quasi - stellar objects ( qsos ) that form at high-@xmath0 redshifts.   the structure of the qso absorption traces the matter density of the universe back along the line of sight to the quasars, where the gas making up the intergalactic medium is in photoionization equilibrium, which results in a tight density  temperature relation for the absorbing material with the neutral hydrogen density proportional to a power of the baryon density. here   i discuss two areas where the forest can be used to constrain cosmology and astrophysics : measuring the matter power spectrum at high redshift and measuring the flux cross - spectrum to the cosmic variance limit.
we present a simple two - dimensional model of electron scattering by interface roughness in double - barrier structures ( dbs ) and its relationship with the vertical transport properties of the dbs.   the model is based on the effective - mass approximation, describing a disordered sample ( e.g. an imperfect dbs connected to two perfectly ohmic leads ) that is characterized by periodic roughness with random relative phases at the interfaces. using the transfer - matrix method, we find a solution for the ben daniel - duke equation for the envelope function @xmath4\psi(y, z)=e\psisi( y, z).\ ] where @x Math5 denotes the coordinate along the growth direction. from this solution, we derive the single - electron schrdinger equation within the framework of the one - band effective - masses approximation.    the results are compared with the results obtained by means of transmission electron microscopy and x - ray scattering. as a result  , it is found that the model can be used to study the relationship between surface disorder and the transmission properties of dbs and that the correlation length of the surface disorder depends on the size of the roughness lateral size
the existence of the relic neutrino remains elusive in the laboratory because of the smallness of its mass and the feebleness of the weak interaction.   we have developed a method to predict the phase space distribution of relic neut rinos in our local neighbourhood at earth ( @xmath3 from the galactic centre ) as well as in outer space using parametric halo density profiles from high resolution simulations of the cold dark matter ( cdm ) halo profile, and to study the effects of gravitational clustering on the observed values of the number density of these neutrinos. with these predictions, we determine the precise implications of this clustering for future direct search experiments.
exchange bias phenomena in layered structures and nanostructures attract a great deal of research effort related to fundamental issues regarding the underlying magnetization reversal mechanism and also their numerous technological applications ranging from biomedicine to magnetic recording industry.   the large number of different systems that exhibit exchange biasing ( eb ), in combination with the lack of exact information on the interfacial spin structure in each case, are two main limiting factors in establishing a global theory of the exchange bias effect. here   we show that the coercivity of the hard - soft ( hs ) co - based ferromagnetic ( fm ) bilayer system is strongly correlated with the interface exchange coupling between the hard fm and the soft fm layer, which is found to be stronger in the weak coupling limit than in the strong coupling limit. by varying the temperature and the thickness of the hs bilayer   it is possible to study the interaction between the fm layers and the af layers at the interface of the bilayers and find out the influence of the surface anisotropy of the bifurcation layer on the coercivities of the two bilayers. as a function of temperature   both the fe / co
graphene has drawn a lot of interest not only for its unique electronic properties but also for its unusual magnetic properties.   magnetic ordering is typically observed in materials with partially filled d or f shell electrons. here  , we have studied the magnetic property of graphene oxide ( go ) and partially reduced graphene oxide(rgo ) from room temperature ( 300k ) down to 10k.we find that both go and rgo show hysteresis at room temperature and as the temperature is lowered the hystereis loop diminishes. however, the effect of lowering the temperature on the behaviour of hyste Residualization is not well understood. in this paper   we will address this anomalous behaviour of diminishing of hy Steresis loop upon lower the temperature for both go & rgo and try to understand the difference in the magnetic behaviour between these two materials.
we study the impact of network structure on the dynamics of random walks in a stochastic temporal network.   we first derive an analytical expression for the mean recurrence time for the active random walk, and then consider a different non - renewal process, called the passive random walked, in which interevent times are reset only on the links traversed at each jump. using the fact that the passive walking process shows a stronger non - markovianity than the active walking process, we derive a generalized master equation for the stationary density and mean recurrences of the two types of walks. to test our analytical predictions, we perform numerical simulations to test the analytical predictions and compare their results.
we report gas dynamical simulations of a deprojected mass model of the galactic bulge using a two - dimensional ( 2d ) ` smoothed particle hydrodynamics'( sph ) method.   we compare the results to the observed spiral arm structure of the galaxy, which is consistent with a four armed spiral pattern in the near - ir near - infrared ( nir ) maps obtained with dirbe and dwek _ et al. from the cobe satellite. by assuming that the bulge has three mutually orthogonal planes of symmetry  , we recover approximately the 3d distribution of nir light in the galactic center for @xmath1, and assume that the potential rotates with a constant pattern speed, such that the corotation radius falls between the molecular ring and the 3-kpc - arm at@xmath6.0 cm2. here we show that the model arms give a reasonable representation of the locations of hii regions and giant molecular clouds in the @x Maths 0-diagram. however, the model arm tangents are somewhat smaller than those of the observed 3- kerr & westerhout's ( 2003 ) radial arm.
abstractin this letter, we discuss the potential for imaging planetary companions in wide ( @xmath135au ) orbits around nearby white dwarfs.   we investigate the probability of a planetary system surviving the late stages of stellar evolution and suggest suitable target white dwarf stars for these studies.    we also discuss the detectability of any surviving planets, suggest suitable targets for white dwarf imaging, and discuss the expected frequency of wide planetary companions to white dwarf.
the electronic properties of bilayer graphene ( blg ) have been extensively studied since its fabrication in 2004 and the documentation of its remarkable electronic properties @xcite has fuelled speculation as to their role in the next generation of electronic and spintronic devices.   we report on the prediction that a biased blg ribbon under a layer - asymmetric strain ( where the upper layer undergoes compression and lower layer tension or visa - versa ) will first be converted from a direct to an indirect band gap material and, under larger bending strains, will then convert back from a semiconductor to a semimetal. this transition will lead to longer lifetimes for electron - hole pairs at the band minima since direct recombination no longer conserves momentum and hence is suppressed - a feature that could be useful in applications where carrier lifetime is important.
dy cen is a hot r coronae borealis ( rcb ) star with a supergiant - like atmosphere that is very h - deficient, he - rich and c - rich.   it is also one of the most hydrogen - rich rcb stars but is very fe - poor with a very high s / fe ratio. in this paper  , we analyse the nebular lines in the optical spectrum of dy cen and their evolution over two decades from 1989 to 2010 using a combination of photospheric absorption lines and spectroscopic observations. at the same time, the electron density of the  6717 and 6731 emission lines has increased about eight - fold. these lines were first detected in 1989 and attributed to a nebula around dy centauri. however, inspection of earlier spectra show that physical conditions in the region emitting the nebulae have changed since 1989. in particular, the flux of electrons from the nebula into the outermost layer of the star s atmosphere has increased by about 8-fold. as a result, the mass of the nebulum has decreased by about 50% since 1989 and the number of nebular emissions has increased more than 10-fold
the main goal of this paper is to develop a general theory of flag bicolorings and the related concepts of coverings and pseudo - orientations.   the concept of consistent colorings of the flags of a map with two colors has appeared previously in literature in different contexts, but its applicability to maps has not been well studied. here   we show that the idea of consistent colored flags of maps can be used as a tool to work with automorphisms of maps. for each possible group of maps, which surfaces admit maps with a bicoloring of flags, we find that the set of bicolors of any map can be given a natural group structure. for all possible groups of surfaces,   it is possible to find the surface which admits maps with the given group of b Nicolorings. using the example of the cube as an example, we explore the impact of operations on topological equivalence of maps by considering the influence of pseudo - orientation on bicolourings of flags. from these results  , we conclude that the use of the term " double cover " on maps is not limited to maps with symmetries, but can also be applied to maps without symmet
a key feature of the symmetry - breaking phase transitions of type - i superconductors is the creation of topological defects, frustrations of the unbroken phase within the broken one, arising from the continuity of the order parameter values.   these objects can appear as magnetic monopoles or point - like defects, cosmic strings, vortices or flux tubes, magnetic domain walls or textures. in this work  , we try to account for this more elaborate behavior and to estimate to which extent it affects the density predictions of the kibble - zurek ( k - z ) mechanism for the generation of these defects in high-@xmath2 materials @xcite. using a new defect generation mechanism, based on a local gauge treatment by hindmarsh and rajantie ( h - r ) , we find that the predicted defect densities are well below the first carmi - polturak experimental sensitivity, although they are still in good agreement with the results of experiments conducted in type - ii superconducting materials, which exhibit a higher critical temperature and are therefore easier to manipulate. however, the existence of a quantity analogous to the magnetic field, which could be a key player in the
meson - antimeson mixing in the charm sector of the @xmath1-@xmath7 quark system has been observed by the babar   @xcite and belle   belle collaborations.   this has motivated attempts to indirectly detect new physics ( np ) signals by comparing the observed meson mixing with predictions of the standard model ( sm ). here  , we present a comprehensive up - to - date theoretical analysis of the results of these experiments in light of the proposed new physics contributions to @x math3 meson Mixing. using the heavy flavor averaging group ( hfag ) data, we show that the observed mixing signal for @x Math14 is consistent with the sm predictions but contains significant hadronic uncertainties, which can be explained by the fact that the mixing rate is sufficiently small that the np component might be able to compete  . moreover, we find that the measured mixing signal lies between the extreme limiting cases of constructive and destructive interference from any np model, so that the sm contribution to the mixing signal is likely to be negligible.
nasa s  kepler _ mission has discovered that many of the planetary systems around solar - type stars contain multiple planets ( kepler multis, *???   * ; *?????,we investigate the spacing distribution among the closely packed multi systems ( 4 planets and more ).   we find that, adopting realistic planetary masses and ages, kepler high multiple systems are packed close to the boundary of stability. in order to explain this proximity, we propose that the primordial systems had a range of spacing, but the ones that were packed too closely have been sculpted away by the subsequent billions of years of evolution. if this is the case, we may be able to recover the primeordial spacing of planetary systems.
we explore the adsorption of molybdenum disulfide ( mos@xmath0 ) on a variety of metal substrates by means of first - principles density functional theory ( dft ) calculations.   we test and compare results obtained with a van der waals functional, designed to describe weak, van derwaals, interactions,@xcite to results obtained using generalized gradient approximation ( gga ) and local density approximation ( lda ) functionals, which are conventionally used to describe chemical bonding. in the case of strong chemical bonding,   the structure and electronic structure of the adsorbate are significantly perturbed by the presence of a strong interaction with the metal surface, while that with a weak interface bonding is preserved.
quantum dots ( qds ) have played a prominent role in the investigation of the kondo problem physics in recent years, @xcite, as they allow a systematic and well - controlled variation of structure parameters, with the consequent exploration of electronic correlations in this paramount many - body state.   one of the main signatures of the Kondo state is the enhancement of the quasi - particle density of states at the fermi level, which is accessible in electronic transport experiments, as it opens an additional transport channel, which can be readily seen in the differential conductance of these structures ( typically in the zero - bias limit ). in the case of multiple qd geometries, the kondos and other single - particle  like resonances provide different transport channels which can even interfere with one another, and as a result, these structures offer the interesting possibility of controlling the transport properties by exploiting quantum interference in the electronic propagation, allowing the study of scattering phenomena such as the well - known fano and aharonov - bohm effects,@xcite competing with thekondo effect. here   we show that the electronic analogue of the dicke effect in quantum optics, the spontaneous emission of closely
entanglement is the property of states of multipartite quantum systems that is the most important resource for quantum information processing.   it is in principle a very hard task to establish entanglement at large distances due to decoherence and attenuation effects. here   we present a new protocol for quantum communication using quantum repeaters, which use purification and swapping methods that lead to polynomial decay only. by using classical communications,   the parties establish whether there exists an infinite percolating cluster ( or one spanning the lattice ) and perform a series of entanglements between any two ( widely separated ) nodes that belong to this cluster. as a baseline to evaluate other protocols, we show that even optimal local operations and classical communication ( locc ) strategies only allow the establishment of Entanglement between distant nodes that decays exponentially with both the distance, as well as the quality of entangled bonds.
the aim of this paper is to present a novel weak galerkin finite element method for solving the stationary stokes equations.   the problem is a model for the flow of an incompressible viscous fluid confined in a polygonal or polyhedral domain @xmath0. as a model, we consider the following equations for unknown velocity and pressure functions : @x math2 for unknown velocities and pressure function@xmath4 for unknown pressure.    the numerical method for the weak form of the stokes problem is presented using the wg finite element technique for partial differential equations where differential operators are approximated as distributions for generalized functions.. the unique solvability of the proposed method follows directly from that of the traditional gradient - divergence variational form for the brinkman equations.
complex social networks arise in a wide range of contexts, for example as corporate partnership networks, scientist collaboration networks, company director networks, film actors networks, sexual contact networks, etc.   while there is an apparent increase in the number of network models in the literature, not all of these models have taken full advantage of the sociological and psychological insights on how social networks may be formed. here   we suggest that, by including baseline spatial homophily into our network model, one can reproduce all of the following features : low tie density, short average geodesic distances, low potential tie pool, low probability of forming ties with people who are not like us, and high probability of having friends who are like us.
the * ka*rlsruhe * tri*tium * n*eutrino ( katrin ) experiment will measure the absolute neutrino mass using a strong gaseous molecular tritium source and an electro - static filter of unprecedented energy resolution.   the experiment is currently under construction at forschungszentrum karlsruhe ( fzk ), germany. in this article  , we describe the experimental design, construction and commissioning of the experiment.
this presentation is a cartoon of the effective field theory of two and three nucleon systems as it has emerged in the last three years.   i will mainly concentrate on the theory in which pions are integrated out as explicit degrees of freedom, but also comment on the extensions to include pions. for this purpose,   the most general chirally invariant lagrangean consists of contact interactions between non - relativistic nucleons and pions, with the first terms reading @xmath2\;+   \;g_a n^{\dagger } \vec{a}\cdot\vec{\sigma } n\;-    0. \ ( n^ {{\mathrm{t } } } p^i n)\ ;   & -\;c_0 (n^{{\ mathrm{ t } p ^i n)^{\b}^{n}=\frac{(n^}}\sqrt {t } = \sqrt{r}{p}{n}_{1 } + \sqr{n } + 1}. the power counting scheme is discussed, and the regularisation scheme is introduced.
the optical flash of gamma - ray burst ( grb ) 120308a is believed to be powered by the reverse shock generated in the interaction between the outflow and the circum - burst medium.   the polarization measurement of the a quickly - decaying optical emission of grb 090102 got a linear polarization degree @xmath4 and has been taken as the evidence for the presence of large - scale magnetic fields originating in the expanding fireball @xcite. in this work   we examine whether the afterglow data is in support of the reversed shock origin of the early optical emission or not.. the answer is positive, hence we estimate the magnetization degree of the out flow.
strong ovi absorptions observed around starforming galaxies at @xmath8 with impact parameter as high as 150 kpc reveal huge gaseous galactic haloes @xcite.   even conservative estimates lead to amount of gas in them far exceeding the gas reservoir in galaxies themselves, which is based on the assumption that gas in the haloes has solar metallicity. here   we show that the observed column densities of ovi correspond to at least half order of magnitude less massive haloes, which can stay in a much wider range of physical parameters under time - dependent conditions.
the qcd sum rule ( qcd - sr ) approach to qcd is a highly active field.   while the approach has been applied to a variety of hadronic observables in both vacuum and finite density nuclear matter, a comprehensive review of the systematic errors associated with the method has not been considered.. the focus of this paper is to establish a rigorous procedure for extracting quantities of phenomenological interest from qcdSum rules.    the main conclusion of this investigation is that qcdsum rules work and they are predictive when the analysis is done rigorously.
we study the spectrum and wave function of helical edge modes of bernevig, hugues and zhang ( bhz ) topological insulator in the @xmath11-edge geometry.   the model is a tight - binding model of a two - dimensional ( 2d ) layer of hgte / cdte quantum well with an internal spin-@xmath14 degree of freedom on each site of the square lattice. as a consequence of the specific way how " hidden " dirac cones ( or valleys ) in the 2d spectrum are projected onto the 1d edge axis,   edge modes show some unexpected behaviors. in particular, the sign of spin hall conductivity changes discontinuously as the mass parameters of the model are varied. for the first time, we show that the transition from a metallic surface state to a non - metallic one in the bulk is due to the existence of gapless edge modes at the edges of the system which are robust against weak perturbations preserving the time - reversal symmetry.
the lisa mission is a collaboration between esa and nasa to build and operate a space - based laser interferometer aimed at detecting and studying gravitational waves of astrophysical origin.   the current schedule places the launch around the year 2011, and the 3 - 10 years observation period is expected to produce a number of observations of galactic binaries @xcite, of massive black hole mergers and captures, and possibly of a cosmological stochastic background@xcite. in this context  , we present here a study of the accuracy that can be expected for the characterization of the noise in the lisa detector once it has been placed in its heliocentric orbit. by relying on all the possible cross - spectra between the interferometric combinations that are sensitive to gravitational radiation and the symmetrized - sagnac combination, we show that closure for the solution to the noise characterization problem does not exist, and that only approximate solutions can be implemented.
the theory of phase transitions in multilayers has been extensively studied theoretically and, to a variable extent, experimentally in the field of magnetic heterostructures.   this paper addresses the problem of universal features associated with large scale ordering in superlattices, which are built of atomically thick layers of two magnets, which taken separately both order through second order phase transitions at two respective bulk critical points. for simplicity, we consider the simplest model of a superlattenice constructed of two elementary building blocks : slabs of two ferromagnets of finite thickness of molecular layers of the same material ( @xcite ) that are stacked periodically in the @xmath9-direction. by taking into account the bulk critical properties of the two components and the geometrical geometry of the system, we show that the long - range ferromagnetic order observed in the limit of thin layers of atomsically thick slabs can be explained by a crossover from the surface critical behavior characteristic of bulk samples to the@xmath17-dimensional critical behavior of the single component at the interface separating the near - critical side of the interface, where the first one imposes a magnetic field acting at the surface of the second component.
the @xcite coarse - grained ( cg ) approach to state - dependent pair interactions in condensed matter physics, chemistry, and material science is discussed.   the idea is to replace the complex interactions of many - body interactions with state - independent potentials that are usually taken to be pairwise additive for computational efficiency and that are therefore more tractable from a theoretical and/or numerical point of view. within the cg approach   we replace the microscopic system at a given thermodynamic state with a cg system of monoatomic molecules that interact by means of state - dependant pair potentials fixed by a structural requirement, the equality of a specific pair distribution function at a certain thermodynamics state.    we discuss the structural approach, which dates back to the early days of liquid state theory, using the three - body axilrod - teller potential@xcite, for a very general class of classical systems. as a result  , we find that the proposed potentials are suitable for a wide range of systems, ranging from noble gases to soft - matter systems, where the complexity lies in the number of atoms involved rather than in the nature of the atom - atom interactions.
the twin paradox ( twp ) theorem is one of the most famous predictions of special relativity.   it predicts that if a twin makes a journey into space, he will return to find that he has aged less than his twin brother who stayed at home. in this paper   we use the axiomatic method to provide a logic - based conceptual analysis of the twp theorem. using the first - order logic ( fol ) framework of @xcite, @excite,@xcite we show that twp is logically weaker than a prediction ( slowing down of moving clocks ) as well as a symmetry axiom of special relativistic theory. since we prove our geometrical characterization of twp in a general kinematic setting, we can use it to derive consequences on newtonian kinematics too. by comparing twp with a symmetric axiom and a prediction  , we also show that the absoluteness of time is not equivalent to the lack of the twin paradox without assuming a strong theoretical axiom.
the atlas experiment ( http://www.atlasasci.org/atlas/ ) has been used to measure the suppression of hadron production at high transverse momentum ( @xmath2 ) originating from parton fragmentation in heavy ion ( hi ) collisions.   this analysis uses data collected with the atlas detector in the 2010 and 2011 pb+pb runs with @x Math5@xmath6tev.    the results show that the rate of jet yields per nucleon - nucleon interaction in central collisions is a factor of two lower than those measured in p+p collisions, which is consistent with the first results from the lhc experiments ( e.g. @xcite ). for large longitudinal jet momentum fractions carried by the charged particles,   the suppression is similar to that observed in hot dense matter collisions.
the ultimate fate of the gas which cools in cooling flows is still unknown.   we show that thermal equilibrium can be achieved at very low temperatures inside the cooling flow region mainly due to @xmath2-cooling.
the evolution of a satellite galaxy has been studied by a number of researchers both theoretically and using numerical simulations.   previous theoretical studies based on chandrasekhar s dynamical friction formula ( @xcite ) predicted circularization of the orbit, but there was rather serious qualitative difference between the simulation result and the theoretical model. in this paper, we perform a self - consistent @xmath0-body simulation of the evolution of the satellite galaxy, in which both the satellite and the parent galaxy are treated as an @x Math0- body system. to obtain the best agreement between the two models, we use the coulomb logarithm as a fitting parameter for the impact parameter.. the results show that the simulation results are quite consistent with the theoretical results, when the integration over the impact parameters is carried out correctly.
the cosmological expansion is accelerating now and that the universe is spatially flat, provided the dark energy density responsible for the acceleration is close to or time independent.   it has been known for a while that the standard @xmath4cdm model of dark energy is reasonably compatible with most observational constraints ( e.g., snia apparent magnitude versus redshift data, cosmic microwave background anisotropy measurements, and baryon acoustic oscillation peak length scale data ). in this paper   we study two dark energy models ( with dark energy being either a Cosmological constant or a slowly - evolving scalar field ) as well as a dark energy parameterization. using the x - ray diffraction ( xcdm ) parameterization we find that the time - independent dark energy theory is the simplest, complete and consistent model of slowly - decreasing dark energy ; however, the black hole model is the most complex and the best fit to the observed data is not supported by the xcd mappings.
the fractional generalization of the schrdinger equation to the diffusion equation is a well - studied example with many special cases to draw on.   the nlse is an integrable equation with detailed solutions in terms of solitons. by performing an imaginary time rotation the schndinger equation can be transformed to the diffusible diffusion equation, which is highly effective in describing the propagation of ground water through soil. here   we explore the interplay between the nonlinearity and fractional derivatives in the fractional sch thirdinger equation. using the riemann - liouville and caputo fractional derivative methods, we find that the linear limit of the fde is found to be the same as the effective limit of quantum many - body description of bose - einstein condensates, while the effective limits of the other two types of effective partial differential equations ( pdes ) are much more difficult to solve. for both types of pdes,   our results show that the combination of the caputo derivative and the variational iteration method is more effective than the adomian decomposition method in reducing the problem to a single scalar pde / ode.
abstractthe aim of this work is the investigation of the structure of cool accretion discs in semidetached binaries.   the results of 3d gasdynamical simulation of flow structure for the case when radiative cooling is effective and the gas temperature drops down to @xmath6  k in the whole region confirm the hypothesis of possible formation of a spiral wave of a new type in the inner regions of the accretion disc where gasd dynamical perturbations are negligible. as compared to the ` hot'case, the ` cool'case has more circular form and the second arm of the tidal spiral wave is present in the outer part of the disc. however, the spiral wave does not propagate to the inner part of these discs and is found to be generated by the tidal influence of the mass - losing star in the place where the stream of matter from the inner lagrangian point@xmath9 should be the main stream.    the mechanism of formation of such a wave and its parameters are discussed.
we propose a new sparse signal recovery algorithm for binary compressed sensing based on neural networks.   the proposed algorithm is based on the majority voting neural networks composed of several independently trained neural networks, which are feedforward 3-layer neural networks employing the sigmoid function as an activation function. in this paper  , we show that the main advantage of the proposed method is that it is suitable for hardware implementation in order to achieve high speed signal processing and energy efficiency.
in the field of information retrieval, word occurrences are not random but vary greatly from document to document.   several adaptive language modelling approaches have been proposed to model variable word rate. in this paper  , we outline the theoretical background for modelling the variable word rates, and illustrate a key observation that word rates are not static using spoken data transcripts. by assuming randomness in a poisson process, we show that the word rate is variable and may be modelled using a poisson distribution or a continuous mixture of poissons. an approach to estimating relative frequencies using prior information of word occurrences   is presented which is integrated with standard @xmath0-gram modelling. using the darpa / nist 4e north american broadcast news task,   the approach demonstrates the reduction of perplexity up to 10%.
nucleon - nucleus collisions at ultrarelativistic energies create hadronic matter at high energy density.   the distributions of baryons at mid - rapidity provide a sensitive probe of the collision dynamics. in this study, we present proton and antiproton measurements using the na44 spectrometer from @xmath0 ( to approximate@xmath1 ), proton - nucleus and nucleus - nucleus interactions.. the data show that the rate of proton formation is proportional to the size of the central region of the hadronic medium, and that the stopping power of the protons is dependent on the number of charged particles in the system. for proton beams,   most of the stopped protons are reduced to about 1.6 gev / c, whereas for antiprotons it is between 0.5 and 2.2 gev/c.    the results are consistent with the predictions of the rqmd model, version 1.08 @xcite, which uses a string model of particle production from each nucleon - nucleon collision as a model of hadron rescattering.
the characterization of the orbits supported by an astrophysical potential is of interest in order to study self - consistent models of stellar systems. among regular orbits, those that are resonant and stable are of utmost importance, since they generate entire families of orbits around them : they constitute the backbone of the system. on the other hand, chaotic orbits,   the existence of which in realistic models of galaxies is nowadays beyond doubt, are important to the dynamical evolution of a stellar system.   one of the main consequences of obeying isolating integrals of motion is the dimension of the manifold on which the orbit moves. for an @xmath0-dimensional potential, regular orbits have @x Math0 or more isolatingintegrals, whereas chaotic orbits obey less than @x math0 isolating Integrals or more isolate integrals. here  , we review the current state of the art in the characterization of these orbits.
in this paper we focus on the problem of recovering behavior - related micro choice information from aggregate data, casting this problem as an inference problem concerning the prediction of flows on networks.   we recognise that this type of data comes from dynamic, adaptive behavior systems involving interdependent micro components which give rise to an instantaneous, feedback - adaptive, world : as a basis for predicting agents choices, we cast this as a self - organized, equilibrium seeking system in the form of weighted and binary networks ; we make use of information theoretic entropy - based methods to solve the ill - posed stochastic inverse problem and recover estimates of the unknown binary parameters. to go beyond traditional reductionist modeling and mathematical anomalies, we use a new paradigm that is developing under the name of network science ( network science ). within this framework, we analyse systems within which we analyse adaptive economic behavior in terms of entropic functions that permit the interpretation of adaptive behavioral behavior in ways that permits us to think about it in terms with respect to the context of causal adaptive behavior.
x - ray astronomy has revolutionized our view of the universe, by providing detailed information about many different types of objects at many different wavelengths.   the introduction of x - ray observatories in 1999 by nasa and esa has greatly increased the amount of information available to astronomers about many kinds of objects over many wavelengths. in this review,   we focus on two areas where the contribution of _ xmm - newton  has increased significantly our understanding of the energetic universe.
we study the behavior of different physical quantities at the resonances generated by the maximum of the potential of a semiclassical schrdinger operator.   in particular, we show quantitatively to what extent the presence of these resonances drives the behaviors of the scattering amplitude and of the wave group.
the ads / cft correspondence generates a powerful duality between asymptotically ads gravitational theories and conformal field theories on the ads boundary, which is the simplest and best - studied example of a ` gauge - gravity duality '.   it is hoped that gauge -gravity duality may allow for a better understanding of the strong - weak coupling properties of condensed matter systems in string theory. here   we discuss the explicit construction of families of gravitational solutions which have zero entropy ( or entropy density ) in the extremal limit. to achieve this, we first need to find non - extremal solutions which satisfy the nernst law, that is, those with a finite entropy which goes to zero when the temperature goes to 0 while external parameters are kept fixed. by studying the thermodynamic properties of some classes of extremal black holes and black branes in ads @xcite, we show that most of the cases do not satisfy the third law of thermodynamics, which states that the entropy of a system should vanish in the zero temperature limit. however, we also show that there are some cases in which the entropy can be found to go to zero at zero temperature, thus violating the third Law of therm
semi - supervised learning has attracted the attention of many researchers because of the importance of combining unlabeled data with labeled data.   this paper concerns the issue of how to address uncertainty quantification in such classification methods. in doing so   we bring together a variety of themes from the mathematical sciences, including optimization, polynomial desorption ( pde ), probability and statistics. using these themes we show that different methods can all be formulated around a common objective function for a real valued function on the nodes of a graph representing the data points : the objective function is proportional to a graph laplacian derived from the unlabelled data and the function involves the labelled data. minimizing this objective function   is one approach to such a classification. by exploiting the graph analogue of the dirichlet energy  , we derive an overarching computational framework suitable for all the models arising from these different assumptions.
we report the results of a new reverberation - mapping campaign for mrk 50, a seyfert 1 galaxy at redshift @xmath17.   we detect a robust reverberation signal and a significant velocity - resolved reverberation response across the broad h@xmath3emission line, which is a region of strong broad - line variability in the spectrum of the active galactic nucleus ( agn ), and we estimate the mass of the black hole in this region by estimating its mean radius from the reverberation data.
the relativistic analogue of the vlasov - maxwell model of a collisionless plasma, denoted (  ), is given by replacing the initial conditions for the density equation with those for the electric and magnetic fields.   the main difficulty which arises is the loss of strict hyperbolicity of the kinetic system due to the possibility that particle velocities may travel faster than the propagation of signals from the electric or magnetic fields, which do so at the speed of light. here  , we investigate how this affects the well - posedness of solutions for the two versions of ( rvm ), namely, the one - and - one - half - dimensional and the three - dimensional versions, and establish a precise result that guarantees the global existence of solutions as long as velocity characteristics do not assume magnitudes that approach @xmath12. in the first case,   we show that the classical regularity of solutions is ensured by the inclusion of relativism corrections which uniformly constrain the velocity of the charged ions in the plasma. in both cases, however, these corrections are not always sufficient to guarantee the continued smoothness of solution properties, and it is shown that the second case
the gravitational distortion of light bundles from distant sources in the universe provides a unique means to investigate ( the statistical properties of ) the intervening mass distribution.   the cosmic shear effect, which is observable through the image distortion of the distant faint blue galaxy population, offers the opportunity to study statistical characteristics of the intervening large - scale structure. as a scalar quantity, the aperture mass   is ideally suited to probe the full probability distribution of the projected mass density ; in particular, values of @xmath4 far out in the non - gaussian space are expected to show strong non - linear features, e.g., the projection of collapsed haloes. here   we present a new method for measuring the skewness of the optical shear field at wavelength@xmath5, using the two - point statistical measures the rms shear in an aperture and the ellipticity correlation function of the galaxy ellipticities. with the use of the new method, we show that the observed galaxy alignment pattern directly reflects the properties of the intergalactic mass distribution, and that the measured aperture mass is a measure of the magnitude of the galactic shear.
the mass difference of clusters in the universe is one of the most important problems in cosmology.   it has been shown that the mass of clusters is approximately seven to ten times larger than the total combined mass of stars and hot gas in the icm, and that this difference can be explained by a non - minimal coupling between matter and geometry, which is well described by dark matter models. here  , we extend this non - minimally coupled model by using a modified newtonian dynamics ( nmd ) model that introduces higher order curvature terms in the einstein   hilbert action  and, in particular, the modified action @xmath0 theories of gravity. through the use of the virial theorem, we show that the overall mass of a sample of clusters can be estimated through corrections in the gravitational potential that emerge in the weak field limit of these theories. for the first time, we find that the observed mass differences of clusters are explained by the presence of an extra matter component that emerges from the interaction of dark matter with baryonic matter, as well as by the existence of interactions between dark matter and other forms of energy.
we develop a general formalism to describe polytropes in the presence of pressure anisotropy.   we use the polytropic equation of state, which is widely used in the context of newtonian gravity, to model compact objects such as withe dwarfs, neutron stars, and magnetized strange quark stars. using this formalism  , we show that the local anisotropic pressure can be induced by a variety of physical phenomena, including the magnetic field, the radial pressure, and the density of the object. for each of these reasons, we propose a new formalism for the theory of poly tropes based on the isotropic pressure and the mass ( baryonic ) density of a fermi gas with respect to the poly tropical constant @xmath3, where @x Math1 and @x math2 denote the isotropeptides of the pressure and mass, respectively.the method is applied to the case of a completely degenerate gas in the nonrelativistic limit of the schnberg  chandrasekhar limit of a withe dwarf, and it is found to be particularly useful for the study of the effects of magnetic fields on
we study the dimensionality of spacetime on small scales in a quantum field theory of the metric, i.e., a uv completion for gravity, which is extendible up to arbitrarily high energies due to the existence of an interacting fixed point of the renormalization group ( rg ).   we show that the scale - dependence of the momentum - scale dependent newton coupling can be used to test the consistency of the asymptotically safe quantum gravity model with respect to the observed properties of the standard model of particle physics, such as the number of fermions, scalars and gauge bosons, the global symmetries, the observed mass scales, etc. here  , we focus on the effects of graviton - exchange in scattering processes, where the cross - section of the quantum - gravity regime is dominated solely by loop effects. within the truncation of the full renormalized rg flow employed in this work,   the dimensions of the kaluza - klein tower of gravitational states are well approximated at the amplitude level, and the magnitude of the interaction between the two modes is well reproduced by an integral. using these parameters, we find that the scaling of
we investigate the influence of the temperature and chemical potential in the gravitational background of a static einstein universe on the dynamical chiral symmetry breaking ( d@xmath0sb ) in quantum chromodynamics at nonzero densities.   the effects of these factors are investigated in the framework of the nambu  jona - lasinio ( njl ) model, which is well known for its ability to deal with low - energy nonperturbative effects such as color superconductivity and the condensation of charged pions in dense baryonic matter. using an effective potential with finite curvature and nonzero chemical potential,   we show that the effect of the unruh temperature on the phase transitions in dense quark matter due to the creation of a finite quark condensate   @xmath1 has been investigated at zero values of temperature andchemical potential. by taking into account the cosmological constant and the vacuum energy of the expanding universe, we find that the dependence of the thermalization effect of acceleration on the broken color symmetry in color supercondensation can be explained by the expansion of the fermion propagator in powers of small curvature.
the gravitational scattering of two massive particles having various spins is evaluated in the nonrelativistic limit using the effective field theory of gravity.   the calculations of the long distance corrections to the spin - independent interactions are performed by evaluating the leading nonanalytic components of the scattering amplitude at one loop level and by defining a potential in terms of the fourier transform of this amplitude. once spin is introduced into the calculation, additional interaction structures arise, such as a spin - orbit coupling and a spin- spin coupling. at the two - graviton exchange level,   classical and quantum corrections to these leading spin - dependent interactions arise and are calculated as part of our work on loop corrections to form factors of graviton couplings. here   we review our calculational methods and reproduce the long range gravitational scattering amplitude in the case of a pair of spinless particles with spin-0   spin-1/2, spin- 0 spin-1 and spin- 1/2 fermions.. the results demonstrate both the expected universality as well as novel spin -dependent interactions.
the hadronic tensor is a well - known parton model for the 1-particle inclusive leptoproduction of unpolarized leptons and hadrons.   the most general symmetric part of this model is given by & & 2mw_^(h ) ( q ; p s ; p_h s_h ) = ( 2)^4 ^4 ( q + p - p_x - p _h ) + & & |j  0)|p_x ; p#h s #x; p*s_h |j			 \ { ( 1-y + y^2 ) f_t + ( 1 -y)-f_l }, where @xmath0 and@xmath1 are the momenta and spin vectors of target hadron and produced hadron, respectively. in this paper   we show that the antisymmetric part can be extended to include the quark helicity distribution and the twist distribution, with the help of the parton expressions for semi - inclusive structure functions, such as the azimuthal dependence of the z - angle between the lepton scattering plane and the production plane.
quantum - mechanical effects have been recently suggested to play a major role in the stabilization of the bcc phase of solid he @xmath0he at low temperature, and it has been suggested that these effects are responsible for the observed differences in the mean kinetic energy per particle and the mean square displacement of particles around lattice sites.   this hypothesis is tested by comparing experimental and theoretical values of the debye - waller factor @xcite, which is a measure of the distance between nearest - neighboring sites, with values computed from quantum monte carlo ( qmc ) calculations of the same crystal at temperatures between 5 k and 35 k. the results show that the calculated values of @x Math9 are in good agreement with those obtained experimentally for fcc and hcp @x math0he and@xmath1he, but not for the liquid phase @x maths2he, which occurs at considerably lower temperatures and coexists with fluid phases whose physics is dominated by quantum exchanges.
galaxy groups are the scale where segregation begins to occur between mass and light.   the dark matter density profile of galaxy groups has yet to be measured. using the canadian network for observational cosmology 2 ( cnoc2 ) redshift survey data a sample of 192 galaxy groups with a median redshift of 0.33   was identified. in this paper   we present the results of a weak lensing study of the galaxy groups and compare these results with those found from the dynamical analysis of these groups and the weak gravitational lensing detection of hoekstra et al. . when the sample of groups is split into two samples of " rich galaxy groups" and " poor galaxy groups ", divided by velocity dispersion, we find that the density of dark matter in the halos of the groups is significantly higher than expected based on the theory of collisionless cold dark matter ( cdm ). at the same time   there is a strong tangential shear signal in the halo of the group, which is consistent with the hypothesis that the
quantum correlations are expected to exhibit some general scaling behavior, beyond the details of a fine - grained description.   a central question of this type is the following : how does the degree of entanglement specifically depend on the size of the distinguished region?   in particular, does it scale as the volume of the interior  which is meant to be the number of degrees of freedom of the Interior  or, potentially, as the area of the boundary of the separated region? here   we provide a detailed answer to this question in a general setting of harmonic bosonic lattice systems and provide a comprehensive treatment of upper bounds on these quantities. in arbitrary spatial dimensions   the degree for which the von  neumann entropy scales asymptotically is found to be as follows : ( 1 ) the extent of the separation between the interior and the exterior of the regions of the system is proportional to the surface area ; ( 2 ) the length of the two - point correlation length is related to the distance from the interior to the outside of the region ; ( 3 ) the entropy of a reduction is not a meaningful measure of Entanglement ; ( 4 ) the distillable entangler is a measure of ent
x - ray flux variability is a common property of active galactic nuclei ( agn ) and has been shown to be inversely proportional to luminosity.   the purpose of this study was to examine the relationship between x - ray variability and luminosity in a sample of 36 seyfert 1 galaxies from the advanced satellite for cosmology and astrophysics ( _ asca_ ) archive.    we find that the nlsy1 ton s180 result is significantly above the correlation established for the n97a sample ( turner  1998 ) and also shows energy - dependent variability. using excess - variance  , we find an inverse correlation between the variability - luminosity relationship and the observed luminosity distribution in the @xmath1 0.1 - 10 kev band.  very high amplitude variability is observed in the narrow - line seyFert 1s ( nlrsy1s ), which is consistent with scattering in an extended region of the galaxy, but not in the broad - line quasars ( blsy2s ). erythematous variability is found to be strongly correlated with the spectral slope of the optical line widths in the range of fwhm
we present here preliminary results based on the follow - up observations of three galaxy clusters with redshifts between 0.2 and 0.8 in the bright and southern serendipitous high redshift archival rosat cluster ( sharc ) survey.   we use a cosmology with h@xmath4km / s / mpc, @xmath5 and @x math6 to fit the surface brightness profiles of the three clusters. for the first time  , the new generation of x - ray observatory gives capabilities to do precise spectroscopic and imaging analysis at the same time.
we study the effects of substitutional impurities on the density of states and the conductivity of a two  dimensional ( 2d ) square lattice.   the lattices under consideration have square structure for 2d and simple cubic structure for 3d crystals. in the case of the 2d lattice we find a logarithmic van hove singularity at the middle of the band, which is due to the distortion of the commensurability condition for the bragg reflection of the electronic wave on the brillouin zone boundary. in this paper   we also show that the densities of states close to half  filling are affected by umklapp scattering, which causes a relaxation time for the umlapp scattering to the problem, which increases for a deviation from half  fill due to an increase in the concentration of the impurities.
we have recently shown that in the presence of a trigger beam in a tripod standing wave electromagnetically induced transparency ( eit ) configuration @xcite, a probe partially reflected from the periodic structure induced by a strong standing wave eit coupling field undergoes large cross - kerr nonlinear phase shifts.   such a novel configuration is specifically apt for developing a phase - tunable beam splitter in which both the amplitudes and the phases of the trasmitted and reflected beam can be controlled. here  , we provide a comprehensive theoretical study of the problem, including a proper treatment of the population redistribution. using analytical methodologies used to describe propagation effects in both nonlinear and spatially periodic media, and allowing us to numerically examine the phase shifts of the reflected and transmitted probe field induced by the trigger s presence over a wide range of probe detunings as well as their dependence on various parameters characterizing both the atomic medium and the three laser fields, we show that the tripod standing waves eit configuration makes control over the cross -kerr effect more versatile than for a running wave ei configuration in which no reflected beam appears.see research article http://www.biomedcentral.com/
we present a simple formula for the fermion determinant of 2-d wilson lattice fermions in a scalar background field ( eq.  (  ).   the proof is based on a result for the hopping expansion for a generalized 8-vertex model where the vertices are coupled to a background field @xcite. with a proper choice of the vertex weights the square of the partition function for this model represents the2-d fermium determinant in an external field. by doing so   it is possible to explicitly integrate out the external field and by using a gaussian action for the scalar   external field we generate a loop representation of the 2-D gross - neveu model.
the elko field is a class of non - standard spinors ( nss ) that are naturally neutral and have mass dimension one.   they are also good candidates to dark matter, since they satisfy only a klein - gordon type equation. in this paper   we study the elko Field coupled to gravity in a einstein - cartan framework following recent results @xcite, and we show how it can be the responsible for all phases of the universe, starting as an inflaton field, something similar to the standard scalar field but with a much more rich structure, then reproducing the matter dominated era, since it is a natural candidate todark matter, and finishing as a constant field that mimics exactly a cosmological constant term, according to the @xmath7cdm model.
the quantum vacuum is a special type of condensed matter  the ` ether' where the physical laws which we have now can arise emergently as the energy or temperature of the` ether'decreases.   the main advantage of the quantum liquids and gases is that in many respect they are similar to the quantum vacuum of fermionic and bosonic fields. here   we discuss the properties of the black hole physics in the presence of an event horizon in the form of the fermi surface, which gives rise to the emergence of the planck physics at high energy in the vicinity of ( and behind ) the horizon.
most of the global properties of elliptical galaxies can be explained by a sequence of stellar mergers between disk galaxies of mass ratios between 1:1 and 4:1.   we tested 14 different relative orientations for every mass ratio, adopting that mergers occur randomly without any preferred relative inclination. in all cases   the merger remnants are found to be of the same mass ratio as the original disk - galaxies. however, even with 2:1 merger remnants we fail to reproduce the fastest observed rotators with @xmath7 at one effective radius. from these results   it is concluded that the evolution of the structure of the initial disk is a process of disruption rather than a series of mergers.
we report a series of optical and radio observations of the ultraluminous super - strong x - ray sources ( sss ) in m101 ( cxouj140332.3 + 542103  ) in 2004 january, march, may, and july from the low state to the outburst.   we also present the results of an _ xmm - newton  follow - up observation conducted about two weeks after the first outburst observation. during the outburst,   the source was found to be very bright ( @xmath3 ) off - nucleus, variable x - rays with a luminosity that exceeds the eddington luminosity of a@xmath4 black hole ( bh ). at the time of the observation, there were enough photons to rebin the spectra with at least 15 counts per spectral bin, and the best - fitting parameters were obtained by using @x math7 statistics. for the high - resolution data taken during the low states, the maximum observed luminosity was ~1.5 times higher than those obtained by the previous observations. on the other hand, the peak of the source activity was about 30 ks away from the center of the galaxy.
the noon states, as an intereting multi - particle entangled states, are the fundamental resource of quantum information processing ( qip ).   many theoretical and experimental schemes have been proposed for generating the noon states via optical components @xcite, cold atomic ensemble @xmathite, superconducting circuits@xcite and cavity quantum electrodynamics ( qed ). however, all of these systems are always affected by the various of external factors which will induce the decoherence and affect the probability of success, even destroy the entanglement. in this paper  , we propose a scheme for generation of atomic noon states of two sets of the atoms via adiabatic passage. in the scheme,   a double @x Math0-type three - level atom is trapped in a bimodal cavity and two set of @x math0- type three - levels atoms are translated into and outside of two single mode cavities respectively. after a series of operations and suitable interaction time,    the arbitrary large-@xmath1 entangled noon states can be obtained by performing a single projective measurement on the double @Xmath0- Type 3-level atom.. the scheme
we have calculated a galactic chemical evolution model ( gcem ) for the milky way galaxy ( mwg ), which reproduces most of the observed data.   the model results are in agreement with the observed trends showing that the low mass galaxies maintain a flat behavior in the plane with an almost constant abundance n / o - o / h even for oxygen abundances as low as @xmath4, while the massive galaxies show a different trend in that plane depending on their star formation history. using different star formation rate efficiencies, we obtain different results of abundances for the whole set of models.
the nature of @xmath0 carinae has been the subject of an intense debate for the last three decades.   the prevailing view was that it is a single luminous blue variable star ( lbv ), but the spectroscopic events - fading of high excitation lines - occasionally observed were interpreted as being imprints of s doradus oscillations @xcite. however, the regularity of the 5.5 year cycle makes such a hypothesis unlikely. in this letter   we report the results of a campaign to study the spectra of@x Math0 carinee during the 1997-1998 cycle. at optical / near - infrared and radio wavelengths, the event observed in 1997 through 1998 is due to a cause different from that in x - rays, despite their temporal coincidence. following damineli, lopes, & conti ( 1999 ) ( dcl ), the secondary star is the main source of hard photons, not the wind - wind colliding zone, and the immersion of the companion into the companion s wind prevents hard photons from reaching the external regions of the wind of the primary and the circumstellar gas resulting in a temporary drop in the degree of ionization.
galaxies at redshifts beyond @xmath0 become increasing irregular as a result of rapid gas accretion, strong gravitational instabilities, and distortions produced by massive clumps and mergers.   we examine the evolution of spiral galaxies out to @x Math11 in the hubble ultra deep field ( udf ; *???   * ) using optical acs images of the wfpc2 and wfc3 udf when available, dividing the spiral types into the usual classifications of grand design ( two symmetric arms ), multiple arm ( several long arms with an irregular distribution in the outer parts ), and flocculent ( small patches of star formation throughout the disk ). for each of these morphologies,   the fraction of multiple arm galaxies increases at lower redshift, but the proportion of grandDesigns decreases at higher redshifting. from the high - redshift clumpy phase, the number of globular clusters in the early phase spirals increases more rapidly than in the late - phase clumps, although the size of the clumps is not significantly different between the two phases over the whole redshift range. among the clump - like galaxy types,
adaptation is a common feature of sensory systems, allowing cells to adjust their sensitivity to changes in nutrient availability, stress, and other stimuli.   biological cells, ranging from bacteria to complex eukaryotes, adopt different strategies to fulfill this property, including single - cell organisms and human sensory receptors. however, all of them require substantial amounts of energy to adapt. here, we compare the different biological strategies and design two minimal models which allow adaptation without requiring energy consumption. by considering the advantages brought to the cells by consumption of energy, such as the bypassing of hard - wired cell parameters such as diffusion constants, we suggest that schemes similar to the ones we proposed in our minimal models could have been adopted by ancient protocells, that have evolved into the pathways we now know and study.
nonlinear frequency conversion of microwave or far - infrared signals into the optical domain has been actively used for detection of microwave photons at room temperature.   the main drawback of this method is its low power conversion efficiency, which has been only recently achieved for 100 ghz signal using 16 mw of cw of optical pump at 1560 nm. to overcome this problem,   an all - resonant whispering gallery mode ( wgm ) frequency up - converter with optical nonlinearity has been developed and tested on a lithium niobate wgm resonator with the optical free spectral range ( fsr )   @xmath1 ghz was irradiated by a microwave signal with the frequency near@xmath2 ghz. in this paper   we introduce the interaction hamiltonian which couples the optical pump and microwave signal wave functions ( e.g. photon annihilation operators ) with the stokes and anti - stokes optical upconverted signal. as a result, the energy and angular momentum of the electromagnetic field inside the resonator   are matched in the same way as those of the optical wave functions, leading to a high unity conversion efficiency of about 0.5%.    the effect of
elongated galaxies with bright clumps at one end are visible in deep field images taken with hst or from the ground ; van der bergh et al.   ( 1996 ) called them " tadpoles ".. we used sloan digital sky survey data to determine the ages, masses, and surface densities of the heads and tails in 14 local tadpole galaxies selected from the kiso and michigan surveys of uv - bright local galaxies, and we compared them to tadpols previously studied in the hubble ultra deep field. using these data, we show that the young stellar mass in the head scales linearly with the rest - frame galaxy luminosity, ranging from @xmath0@xmath1 at galaxy absolute magnitude @x Math2 mag to @x math3@x maths1 at @xMath4 mag.    the tails in the local sample look like bulge - free galaxy disks., their photometric ages decrease from several gyr to several hundred myr with increasing redshift. 	 the far - outer intensity profiles in thelocal sample are symmetric and exponential. on the basis of these results,   we suggest that most local tadpole
the study of the effect of periodic forcing on homoclinic loops has been thoroughly investigated in three possible limits : the fast and slow oscillations limits and the small forcing limit.   most of the analytical studies have been performed in the small oscillations regime in which perturbation methods apply. here   we show that for a large class of systems, the phase space structure and its associated transport properties have some common non - monotone dependence on the frequency of the forcing term. to prove this result, we establish that in some cases, even for finite size oscillations, there exists a function which depends on the forced frequency continuously. after some natural scaling,   this function is simply the sum of the areas of the incoming lobes per period, normalized by the forcing period.this proposed viewpoint leads to a non - traditional scaling of the flow which is relevant for studying its behavior near homocinic tangles.
the expansion rate of the universe is of fundamental importance.   the present value of the expansion rate, hubble s constant, has been measured with increasing accuracy @xcite. in this paper   we perform a second - order calculation of the effect of inhomogeneities on the expansion rates of a homogeneous, isotropic friedmann - lematre - robertson - walker ( flrw ) cosmological model and find that the mean corrections are only a few parts in @xmath0. by calculating the variance about the mean value, we uncover an interesting infrared effect. at second order   our results suggest that if the super - hubble modes of@xmath3 have physical significance, then a nonperturbative extension of our calculation could yield a most important modification to the friedmann equation.
we propose an all - optical approach to detune relatively the resonances within a microresonator by exploiting the thermo - optical effect at a local level.   the effect is demonstrated by applying it to a whispering gallery resonator  waveguide system which exhibits fano interference features @xcite. as a particular example, this fine tuning approach allows to access the complete destructive interference point on one side of the fano lineshape, where one of the resonance disappears from the spectrum, as predicted in@xcite.see research article http://www.biomedcentral.com/1471-2148/7/8/9/11/17 for a detailed description of the experimental results and numerical simulations.
we propose an original self- * overload control policy ( soc ) for admission control in distributed autonomic web systems.   the proposed policy is capable of self - configuring its component level parameters according to performance requirements, while at the same time it optimizes its own responsiveness and self - protects from overload. a wide range of experiments has been conducted to test the sensitivity of the proposed solution to the configuration of the few startup parameters. results show that the behavior of our policy is not dependent on the initial parameter setting, while other policies achieve an acceptable performance only when perfectly tuned and in very stable scenarios.
abstractultracompact low - mass x - ray binaries ( lmxbs ) are rare binary systems.   they are believed to consist of a compact star, either a neutron star or a black hole, and a roche lobe - filling, low - masses companion. in this paper   we report the discovery of the likely orbital period of another candidate lmxb 2s  0918@xmath0549 using time - resolved imaging of the source using the 8-m gemini south telescope. based on its optical  to  x - rays flux ratio,   the orbital period has been suggested to be @xmath13 min @xcite. as a result, the source distance is probably 4.15.4 kpc.
mass loss in massive stars plays an important role in determining their evolution and how they end as supernovae.   the underlying physics of stellar winds and mass loss is still not well - understood across the hertzsprung - russell diagram ( hrd ), but it is beginning to be clear that pulsation can drive mass loss in some stars. in this review,   i present a tour of the hrd of stars where pulsation - driven mass loss occurs, including cepheids, luminous blue variable stars and red supergiant stars, and discuss progress in understanding how pulsation drives mass loss.
we have imaged the @xmath0 quasar pc1643 + 4631a in the c|c|cc band with two broad band filters and a third one that forks the break in the spectrum.   we find that the quasar has a damped lyman-@xmath7 system ( dls ) which is perfectly positioned between the johnson @x Math1 and @x math2 filters, allowing the detection of a wide range of galaxy candidates in the redshift range @x maths4  @xMath9. among them, we find five galaxies with a typical magnitude at a redshift of ~3.5  0.6 arcsecs below the limit of the observed emission line.
a growing body of complementary cosmological data are suggesting that the universe underwent a late time transition from a decelerating to an accelerating expansion.   current data are accurately fitted by a flat frw type cosmology containing nonrelativistic matter plus some sort of dark energy @xcite. in this context, we constrain the free parameters of a flat accelerating cdm cosmology recently proposed in the literature@xcite and show that it is consistent with the sne ia ( constitution sample ) and h(z ) data using a cold dark matter component only. at redshifts of the order of a few, the hubble constant does not need to be small in order to solve the age problem. for the first time, we also show that the existence of a transition redshift depends exclusively on the @xmath6 parameter.
we quantify the capability of laser interferometers to detect violations of general relativity ( gr ), with a single detection of a compact binary coalescence signal, by assessing if the minimal error on the parameterized post - einsteinian ( ppe ) parameters are larger than the separation of modified gravity values with respect to standard gr values.   error bounds are computed with the most accurate frequentist approach to date by computing the errors as inverse power series in the signal - to - noise ratio ( snr ), where the first order is the inverse of the fisher information matrix. in this paper   we model gr violations with the ppe framework, which produces parametrized extensions of gravitational waves ( gws ) signals for the inspiral phase only of a binary compact coalescence in the absence of spin ( similar extensions are currently not available for the merger and ringdown phase as well as in the presence of spin ). using second order asymptotics,   the improved bound adopted here ( based on second- and third - order expansions ) is largest than the inverse fisher matrices, known to underestimate errors in low - snr detections. when bayesian uncertainties are smaller than the frequentist bounds, it
charge - density wave ( cdw ) is a quantum state expected in low carrier density systems such as a semimetal or a semiconductor and has been extensively studied both experimentally and theoretically.   the origin of the cdw phase in 1@xmath0-tise@x math1, one of the old transition metal dichalcogenides with a commensurate cdw transition with a @xmath2 superstructure below @x Math3k, is still under debate despite the long and extensive studies so far. here  , we show that the cooperation between coulomb interaction and electron - phonon interaction in a triangular lattice is essential to induce the cdW phase in this material. for the first time, the ground state properties are calculated using the variational monte carlo ( vmc ) method for multiorbital systems  . thecdw phase is observed between the normal metal and band insulator phases with intermediate interband coulomomb interaction. however, the " pure " exciton condensation without lattice distortion is difficult to achieve due to the strong coupling between electronic and lattice degrees of freedom.
the prevalence of dusty, infrared luminous galaxies at early times tests our theories about early galaxy formation and the production of metals.   semi - analytic models predict very small numbers of submillimeter galaxies ( smgs ) at extreme redshifts ( @xmath0 ), and the best observational constraints on the redshift distribution of smgs are consistent with this. in this paper, we discuss the power and limitations of using the far - ir spectral energy distribution ( sed ) peak as a redshift indicator in submillimetre surveys. to test this hypothesis, we apply this technique to the current blast survey of ecdfs and place an upper limit on the number density of 500@xmath6m - selected smgs at @x Math0.. we find that the number of smg - selected from the blast survey is approximately 1% of the total number of potential smgs in the region of interest ( r2 = 0.895 ).
the @xmath9-symmetric charge - parity - time hamiltonians, which commute with a reduced symmetry operator, @x math9, are investigated in the photonic medium.   the hamiltonian is spatially antisymmetric ( odd ), while the hermitian one is even @xcite, and the local gain - loss coefficient of the system is proportional to the strength of the anti - hermitia part, at which the @x Math9 symmetry is broken. by using the kerr nonlinearity in the dynamical equations,   it is possible to design optical settings that would realize non - hermitsmitian hamiltonines featuring the full @x maths1 symmetry, as well as its reduced form,@xmath0.
quantum turbulence ( qt ) is currently one of the most important topics in low temperature physics.   recently we have studied theoretically and numerically spin turbulence ( st ) in spinor becs @xcite, a kind of multicomponent becs with spin degrees of freedom. when the system is highly excited from the ground state, it goes through hydrodynamic instability to st in which the spin density vector has various disordered direction. this st shows characteristic behaviors different from other kinds of qt : first, the spectrum of the spin - dependent interaction energy obeys a -7/3 power law, which is different from the traditional kolmogorov -5/3 Power Law in turbulence in turbulence @xcites.. secondly, the spin densities are spatially random but temporally frozen, which reminds us of the analogy of spin glass.    this article reviews such recent works on st in spin-1 spinor Becs at zero temperature.
we report on the discovery and follow - up observations of the near - infrared ( nir ) and optical transients ( nirt and ot ) associated with the gamma  ray burst ( grb ) event grb990705.   the nir imaging started 6.6 hours after the high - energy event : @xmath0-band images were acquired on 1999 july 5.9, 6.4 and 6.9 at la silla ( chile ) with the 3.58-meter eso - ntt plus sofi with the camera equipped with a hawaii 1024@xmath71024 pixel hgcdte detector. in each image,   two annuli intersecting the _ bepposax _ wide field cameras ( wfc ) error circle were determined by subtracting the mean sky from the data obtained from frames just before and after the source image, and then applying a differential dome flatfield correction. using the reduction of the images, we detected a bright nir transient inside the wfc error box inside the intersection of the _ ulysses _, _ near _ and   _ beccosax_ error boxes. to search for a counterpart at these wavelengths
self - sustained current oscillations in weakly coupled semiconductor doped superlattices ( sls ) are observed when the carrier density is below a critical value.   they are due to the dynamics of the domain wall separating the electric field domains, which moves through the structure and is periodically recycled. despite its practical and theoretical interest,   the effect of temperature on these behaviors is still poorly understood. here  , we derive a discrete drift - diffusion model from microscopic sequential tunneling models and compare numerical simulations of these models with experimental data. by using our formulas for the field - dependent drift velocity at different temperatures ( ranging from 0 to 175 k ), we show that increasing temperature facilitates self - oscillations of the current in the second plateau of the voltage  doping   phase diagram in the @xmath0@xmath1 characteristics of undoped sls. as the temperature increases, voltage windows corresponding to self- or multistability open up in the sl phase diagram. this phenomenon is explained qualitatively by the existence of regions of stationary states where the current alternates with regions of self - cyclic oscillations. furthermore, our numerical results agree with the available experimental data and explain them quant
the large area telescope ( lat ) is the primary instrument on the _ fermi gamma - ray space telescope.   it is a pair - conversion detector of high - energy gamma rays covering the energy range from 20 mev to more than 300 gev. in the near future  , major improvements are expected from the new " pass 8 " data, such as an increased effective area with respect to the current " pass 7 " public data @xcite. these improvements correspond to a radical revision of the lat event - level analysis. during the current preparatory phase of the cherenkov telescope array ( cta ) project,   large computing and storage resources are needed mostly for monte - carlo ( mc ) studies. here   we present the work done to migrate both the cta mc production and its analysis through the dirac ( distributed infrastructure with remote agent control ) framework for both current and future experiments.
the batse  data of all - sky 9.1 years ( 19912000 ) continuous monitoring in the @xmath6-ray range give unique possibility for combined gamma - ray bursts ( grbs ) analysis with x - ray observations.   the current study of broadband spectra is complicated because of insufficient statistics accumulated by broadband instruments and biases due to different instrument responses. here   we perform a search for grbs, inspecting the 2550 kev range for time period not covered by the scan of @xcite with a more careful and optimized for soft grbs procedure.
the cms muon drift tube chambers are used to reconstruct muon tracks as precise as possible.   they are operated at slight overpressure of about 2 - 10  mbar and are equipped with two pressure sensors, one at the inlet and one on the outlet side.. the drift velocity measurement in the velocity drift chamber ( vdc ) can be corrected for the measured overpressure by means of a temperature sensor. during the last few years   the vdc has been used to measure the drift velocities of electron beams crossing the sensitive region between anode and cathode using a scintillating fibre and two silicon photomultipliers. here   we describe the experimental design and operation of this monitor system together with the latest measurements.
gravitational wave ( gw ) observations are expected to provide a new view of relativistic phenomena in the universe.   one of the most promising candidates for the direct detection of gws is the merger of compact binaries such as binary neutron stars ( nss ). here  , we review the current state of knowledge about the electromagnetic counterpart of gw events and discuss the role of macronovae / kilonova as a possible candidate for the detection of gravitational waves from these mergers.
x - ray pulsars are among the most luminous sources in the galaxy.   they are powered by the accretion of material from the " normal " companion onto the neutron star, with the flow channeled onto one or both of the magnetic poles by the strong field. during this process,   gravitational potential energy is converted into kinetic energy, which escapes from the column in the form of x - rays as the gas decelerates through a radiative shock before settling onto the stellar surface. here   we present a new model for the formation of the power - law spectral shape characteristic of x-ray pulsars based on the physical picture originally proposed by davidson ( 1973 ), in which the accreting gas passes through a radiation - dominated shock before settled onto the surface of the star. using the new model, we show that the observed spectra can be explained by the first - order fermi energization of the photons produced by the thermal mound, which is located just above the star's surface.. the upscattering of the escaping photons carries away the kinetic energy of the gas, thereby allowing the plasma to settle onto the stars surface.
brownian motors, acting as thermal fluctuation rectifiers, have been attracting considerable attention in the past ten years mainly due to their potential applications in biology, condensed matter and nanotechnology but also to their theoretical relevancy in statistical mechanics. in most of the cases,   rectification is achieved by means of an external periodic or random perturbation applied to an equilibrium system with some underlying spatial or temporal asymmetry.   however, it is only recently that research has been focused on introducing control in brownian ratchets. in this letter   we propose a modification of the feedback control protocol that may switch off the potential even if that implies a loss of instantaneous velocity, or switch it on when that makes the center of mass initially recede. nevertheless, this new protocol beats the original one for a sufficiently large number of particles.
the counterpart of ultraluminous x - ray sources ( ulxs ) is not known.   most likely there is no universal engine for ulxs, but some may be powered by anisotropic radiation from an intermediate mass black hole ( ibh ) or super eddington luminosity from stellar mass black holes. here   we discuss the possibility that some ulxs are powered by tidal capture of a massive star of mass and radius by an ibh. in order to account for the high ulx luminosities the companion star should be considerably more massive than the captured star, and the combination of a high mass and large size make these stars excellent candidates for tidal capture. using theoretical simulations we show that tidal capture can lead to circularization close to the tidal radius which is the distance from the ibh where the tidal forces equal the forces which keep the star bound. as the star evolves it starts to fill its roche lobe causing it to lose mass to the Ibh.    this leads to high x - rays, provided that the donor is sufficiently massive ; however, when after time the massive donor explodes it turns into a compact remnant ( cr ). during the mass transfer phase   the captured
we study the performance of an ion - trap quantum information processor by using a general model for non - dissipative decoherence, i.e. a random phase drift added by hand at the end of each qubit rotation.   the model is based on the idea that time is a random variable and that the system hamiltonian ( therefore its eigenvalues ) fluctuates during a quantum computation. in order to account for the fluctuations of the raman laser intensity, we use a specific model, which allows us to account with respect to the stochasticity of the experimentally obtained data. as a result  , we find that the quantum computer can not efficiently process quantum information due to the spontaneous decay of the metastable states of the trapped ions. instead, the results are explained by considering the time as a statistical variable and then averaging over a properly defined probability distribution. this approach is model - independent and it is shown to be able to reproduce the results of experiments using a single trapped ion based quantum computing device.
the current understanding of the universe relies on the assumption that the universe is statistically homogeneous and isotropic on sufficiently large scales.   it is in general difficult to prove this assumption in a strictly mathematical sense but it can be verified using different cosmological observations. here   we propose an information theory based method for testing the assumption of isotropy in the local universe using the all - sky 2mass redshift survey ( 2m ) data from the x - ray background ( xrd ) and the galaxy distributions from the 2dfgrs and 2m redshift surveys. by using a @xmath1cdm Cosmological model with three different statistical tools, we show that the distribution of the galaxy masses in the near infrared region of the 2m survey is not completely isotropically distributed across the entire sky.. the results suggest that the observed isotropy is not due to backreaction of large scale structure such as supernovae or cosmic microwave background radiation.
pulsars are expected to be born inside the supernova explosions of massive stars.   the pulsar wind nebulae ( pwne ) initially expand in the freely expanding ejecta of the rapidly expanding supernova, and the reverse shock wave from the super Nova interaction with the surrounding medium eventually makes its way back to the center where it can crush the pwn. here  , i present a picture of the evolution of young pulsars that are likely to be in the earlier phase of evolution, when they are unlikely to have been born inside a supernova explosion. for objects with an approximately constant pulsar power, the expansion in a supernovae is expected to result in the displacement of the radio emitting pwn in the vela remnant, which is then swept up by the radial pulsar.    this scenario is supported by the observation that there is evidence for the existence of an extended supernova remnant around the pwne.
new - physics ( np ) contributions to the decay @xmath19 model - independently are examined.   we show that the measurement of the partial width of the top quark by itself can reveal the presence of np, but it is not known which of the 10 possible four - fermi operators is responsible for the interference.  in particular, we examine the effects of sm - np interference on the triple - product asymmetry of the decay @x math19. using an effective lagrangian, we find that the interference is due to the existence of a non - zero asymmetry, which is caused by the interference of the standard model with the new - physics particle.
the kondo necklace ( kn ) type models are useful to discuss the quantum phase transitions between kondo singlet and antiferromagnetically ordered states such as found in heavy fermion compounds @xcite.   they have been originally proposed as a simplified version of the itinerant kondo lattice ( kl ) model for the one - dimensional case where the kinetic energy of conduction electrons is replaced by an intersite exchange term. here   we investigate the effect of the magnetic field on the quantum critical t - h phase of the kn model for d@xmath22 in a magnetic field using the spin - orbit coupling and crystalline electric field effects involved in the formation of the @xmath1 and * s * ( pseudo- ) kondo spins. at low temperatures the charge fluctuations in the kl model are frozen out and the remaining spin fluctuation spectrum can be simulated by an antifermagnetic inter - site interaction term of immobile @x math1 spins coupled by a kondo interaction to the local noninteracting spins * s*. the influence of higher order terms in the hamiltonian, i.e., the ratio of effective g- factors for the local k
the thermization of a quantum system is a universal phenomenon which holds true for virtually all hamiltonians and sensible choices for the relevant degrees of freedom can be safely disregarded.   this line of research has of late enjoyed cross - fertilization with topical areas such as nanoscale thermodynamics, quantum many - body physics and quantum information, leading to some powerful new results. in the present paper   i wish to add yet another, and rather practical, perspective on the issue of thermalization. when a novel quantum systems is fabricated and investigated in the laboratory for the first time, its precise dynamics and possibly even its constants of the motion are not known in advance. using a combination of experimental and theoretical techniques,   it is shown that the thermodynamic variables that characterize the final equilibrium state of the system are determined by the entropy of the initial state, and hence by the degree of coarse graining that is introduced into the system s microstate during its initial preparation. from these variables   one can predict the final values of the relevant macroscopic degrees offreedom, but only if the experimenter actually controls degrees ofFreedom that are relevant to the problem at hand, either directly in the past or through
the second law of thermodynamics forbids the spontaneous emergence of order from disorder in isolated systems.   however, at the mesoscopic scale, where the entropy production is self - averaging, this constraint is relaxed at single trajectories, and order can sometimes emerge from disorder, and the stochastic entropy produced during a certain protocol can be negative for certain rare trajectories. using the fluctuation theorems, we characterize the statistics of the total time of occurrence of these events by calculating the total fraction of time @xmath18 $ where the Stochastic Entropy Production is negative, which we name as the _ violation fraction_.   in this study, we show that the average violation fraction exhibits its larger possible value than the values of@xmath2 and @x Math1, which are obtained from the detailed fluctuation theorem ( dft ) and the ift and jensen s inequality, respectively. to test our theory, we consider the case of a small mesoscopic system where the probability of an entropy - consuming trajectory is very large and the mean value of the entropy change grows as @x math1 for large @x maths2, while fluctuations grow as @Xmath1 for small @x mathematics3
the energy landscape of a glassy system is typically rugged, made of many local minima ( metastable states ), whose huge number makes it difficult to reach equilibrium.   the structure of a network has however a deep impact on the properties of the dynamical processes which take place on it, and it seems thus adequate to put to use the tools and techniques developed for the analysis of dynamic processes on networks to achieve a better understanding of the energy landscape structure, represented within the context of network theory. in this paper  , we review the current knowledge about the topology of the network of minima, conceived as a tool to characterize the potential energy landscape, and we present a new model of the dynamics of these minima based on the results of a series of numerical simulations.
the neutrino dispersion relation is a complex function @xmath0. according to the thermal field theory ( tft )   the contributions to the real and imaginary parts of the self - energy arise from the temperature and density - dependent part of the neutrinos self - energies. in this work   we use the method of real - time thermal field theoretical calculations to carry out a carefully calculation of the imaginary part of an effective potential for a massless neutrinino propagating in a thermal background composed of electrons, protons, neutrons, neutrines, leptons and neutrons.   our results show that the effects of the nucleons background contributions and the fermion mass correction are not important for the computation of the damping rate.
low mass x - ray binaries ( lmxbs ) are systems in which a low mass ( @xmath1 m@xmath2 ) star transfers matter to either a low magnetic field ( typically @x Math3 g ) neutron star or a black hole.   this paper describes our _ chandra observations of eight such objects listed as candidate lmxb in @xcite ; the accurate locations we derived with _   chandra will enable follow up observations in the infrared / optical.
we have been developing a new system called grape9-mpx ( grape - multi - precision ) which is a dedicated processor for quadruple, hexuple, octuple - precision arithmetic.   we have implemented this processor on a structured asic ( application specific integrated circuit ) board which was called grape - mp @xcite, and on an fpga ( field programmable gate array ) board with a control processor, which was referred to as grape - mpx@xcite. on these systems, we measured the performance of quadruple / hexuple / octupe - precision calculation and obtained the higher performance compared to a software implementation. in this paper, we describe the design and implementation of the new system from both hardware and software viewpoints. at the same time, we present the results of the performance measurement.
we present a formal proof of the correctness of the evolution equation ( - ) as a solution of the flavour - diagonal evolution equation of the quantum field theory ( qcd ).   we derive it in a more systematic way, to understand better its relation to the other widely known and used iterative solutions of eq. (  ), and to prove that its _ exclusive _ content, in terms of the fully differential distribution in all variables, is the same as that of the other well - known iteratively solved versions of eq. for the most common qcd evolution equations of the dglap type   @xcite, with the kernel splitting functions scheme were calculated in qcd at the two levels beyond the leading - logarithmic approximation. using the monte carlo method, we show that the first part of the variance distribution function ( pdf ) can be considered as a single variable, and the second part as a fraction of the hadron momentum carried by the parton of the type, i.e. gluon, quark or antiquark, at the high energy scale. on the other
nonlocality is a fundamental property of quantum mechanics.   recently, shunlong luo and shuangshuang fu have introduced a new way to quantify nonlocality by measurement, which is called the min, and following their treatise, a number of papers emerged to perfect its definition and discuss its properties. in this paper, we analyze how the unruh effect affects the min for both the dirac and bosonic fields and find some new properties.
high resolution ( hr ) topographic data is a major input for flood models, especially for complex environment such as urban and industrial areas, where a detailed topography helps for a better description of the physical properties of the modelled system.   the increasing availability of high resolution topographic datasets and the use of high performance computing ( hpc ) structures, leads to a growing production of hr flood models. at the same time, the level of accuracy of these models might be erroneously interpreted as the accuracy of the hr topographic models, disregarding uncertainty inherent to this type of data use, not without standing the fact that other types of errors also occur in hydraulic modelling. here  , we discuss the influence of modeller choices, when using the hrTopographic data in 2d hydraulic models with respect to their influence on the quality of the produced hr digital elevation model ( dem ).
we test the hypothesis that all broad - lined type ic supernovae ( sne ic - bl ) are powered by magnetars by fitting the magnetar model to the sn light curve and evolution of photospheric velocity and temperature, if available.   we find that the proposed model is valid and reproducible for a large sample of sne ic-bls ( @xmath2 ), including the relativistic slei - bls 2009bb and 2012ap, which are driven by sub - energetic gamma - ray bursts ( grbs ) in the same way as the energetic grb  100316d and grb 140606b from the 1998bw sn  1998 bw event. under such hypothesis,   the fitted model is able to reproduce the luminosity of all known types of broad -lined type icsupernovae except for the superluminous slsne ic@xcite, which is powered by millisecond magnetars.
we explore the possibility of a quantum chromodynamics ( qcd ) nonsupersymmetric gauge dual in @xcite.   the theory studied is qcd with @xmath5 dirac flavors and one adjoint weyl fermion, which is a new gauge theory featuring magnetic quarks and a weyl adjoint fermions, new gauge singlet fermons which can be identified as states composite of the electric variables, as well as scalar states needed to mediate the interactions between the magnetic quark and the gauge single fermional states. for the first time   we show that the gauge dual can be constructed for any number of colors greater than two in the conformal window of the phase diagram provided by the t hooft anomaly conditions for qcd.the results are consistent with the existence of a general asymptotically free gauge theory able to reproduce the infrared dynamics of qcd in terms of its electric dual description at low energy. however, given that we do not start in the ultraviolet with a supersymmetric spectrum nor we impose supersymmetry coupling relations it is legitimate to assume that there are nontrivial infrared fixed points in the magnetic description matching the
we propose a cosmographic method for alleviating the dark degeneracy of dark energy models.   the method is based on the fact that, for vanishing spatial curvature, a homogeneous and isotropic universe is described by one function only, i.e. the scale factor @xmath5, accounting for the total universe energy budget. in this way, we can parameterize separately matter from dark energy in a scheme that depends only on cosmokinematic measurable quantities. using a fully kinematic dark energy reconstruction,   we show that the proposed method is able to fix robust constraints on observables, regardless of any priors imposed from the beginning on @x Math3, thus allowing one to draw distinct information on both matter and dark energy without the need for the cosmological principle.
we propose a technique for data sparsification that is suitable for inferring the topology of a space from which the data is sampled.   the data points are assumed to be sampled from a smooth manifold of known dimension sitting in some euclidean space and are used to sparsify the data so that the resulting set is locally uniform and is still good for homology inference. with respect to the local feature size, the sparsified data is dense enough to be decimated at least to the level of the input data but at the same time keeps it dense enough with respect as much as possible to keep the topological information intact without sacrificing topological fidelity. using this strategy, we construct a rips - like complex using the lean feature size computed for each sample point. following the construction of the complex, we analyze the complex using various mathematical and computational tools developed in computational topology.
we have analyzed the x - ray spectrum and morphology of the giant molecular cloud sgr  b2, which is located over the galactic center ( gc ).   the data were obtained with the _ asca satellite in 1993 october 1 and 1994 september 2224 using four independent data sets : two solid - state imaging spectrometers ( sis0, sis1 ) and two gas imaging spectroscopes ( gis2, gis3 ). for the sis data, we excluded the data taken at geomagnetic cutoff rigidities lower than 6 gev c@xmath15, at elevation angles less than 10@x Math16 for the gis and 5@x math16 forthe sis from the earth rim, or during the passage through the south atlantic anomaly. for each data set, we calculated the total energy of the large - scale plasma and the temperature of the smaller plasma by combining the co molecular lines and the far - infrared dust emissions. to give more quantitative results and implications, we have also calculated the mass of the cloud and the distance between it and the gc.
a fundamental purpose of molecular simulation is the computation of macroscopic quantities, typically through averages of functions of the variables of the system with respect to a given probability measure.   we explore here an alternative approach to this goal, which consists in modifying the kinetic energy of each particle in order to increase the time steps used in the simulation.. previous work has focused on changing the mass matrix of the simulations in orderto increase the number of time steps needed to compute average properties ( e.g., by increasing the integration step size of the stochastic differential equations for the langevin dynamics ). in this work  , we investigate the effect of freezing particles temporarily at each time step on the speed - up of adaptively restrained simulations using a kinetic energy that is set to  0 when the particle s momenta are small, while it remains unchanged for larger momenta. as a result, we find that the convergence of averages over trajectories is very slow, and that transitions between metastable regions are very rare. since, in many cases, inter - particle forces only depend on relative particle positions, and hence do not have to be updated when particles are frozen, our results show that freezing particles may
quantum field theory permits violations of all of the local energy conditions used in classical general relativity.   two of the weakest such local conditions are the " weak energy condition" and the " null energy condition " which state that : @xmath0 for all timelike vectors, and@xmath2 for all null vectors, respectively. here   we show that these local conditions can be averaged over timelikes or null geodesics to obtain a suitable generalization of the averaged energy conditions using uncertainty principle - type inequalities derived from quantum field theories. by applying these inequalities to the case of the casimir vacuum, we find that both the weak and null energy conditions are violated for a wide class of quantum states, including the one which is arguably the most well - known form of quantum matter, the cas Vladimir vacuum.
giant luminous arcs have been discovered in the cores of rich clusters of galaxies.   they provide the best estimates of the mass within few hundred of kpc of the cluster center. however, ground based images generally do not allow one to resolve the arc widths and structures, leading to a considerable uncertainty on both the shape of the density profile and the magnification factor. in this letter   we analyse the lensing properties of the ms 2137 - 2353 core in which two multiple image systems have been observed by the hst ( gioia et al., 1996a).we find no evidence for a fifth image which could be associated to the arc system ( a0, a2 and a4 ). using the standard package stsdas ( task ellipse ) in iraf, we model the galaxy g1 and the contaminating galaxies g1, g7 and the four small galaxies lying within the envelope of g1 with a density profile ranging from 0.12@xmath120.02 in the very center ( r=2 " ) to 0.16@x Math 120.02 beyond r=6 " ( or 34@x math5 kpc ) and p.a.
numerical simulations of galaxy clusters have been used to study the contribution of dark matter to the formation of structure in the universe.   the simulations show that the density profile of the cluster gives rise to an excellent description of the radial mass distribution for halos with a wide range in mass. however, the density profiles of real objects are not always in agreement with the simulations. here   we review the results of a recent study using weak gravitational lensing to estimate the mass - to - light ratio of galaxies in a galaxy cluster and compare the results with those of the simulations.we find that the model is biased by the contributions of local large scale structure ( such as the filaments connecting clusters and groups ), which can be explained by the existence of collisionless cold dark matter. on the other hand, the model does not account for the contributions from distant structures, such as baryons, which are usually ignored in cosmological simulations.
non - spherical particles moving in turbulent flows are of fundamental importance for many different scientific problems.   rotation of planktonic organisms is critical for chemotaxis, and plays an important role in diffusive nutrient uptake. here   we investigate the effect of shape upon the rotation of particles in turbulence, their tumbling, and their spinning. using direct numerical simulations, statistical - model calculations, and experiments, we show that the orientational dynamics of rods and disks are qualitatively very different ( section  ). however, we also show that, despite these significant differences, the variance of angular velocity is almost shape - independent. by comparing the results of our simulations with those obtained in a random - flow model with finite correlation length and time, we find that the rotation rate of large particles within the inertial subrange of turbulence is significantly faster than that of small particles. to test the hypothesis that shape is important for the rotations of non - spherical particle in turbulence  , we experimentally demonstrate this hypothesis by measuring the rotation rates of spheroids and cylinders suspended in linear shear flows.
we investigate quantum transport through a quantum - dot device using a minimal model@xcite where the complex interacting region is replaced by a single spinful orbital which is coupled to two noninteracting leads. a single coulomb matrix element @xmath0 accounts for the charging energy of the device.   we calculate nonequilibrium spectral functions and current - voltage characteristics using the recently introduced scattering - states numerical renormalization group ( snrg ) approach as well as different approximations within the diagrammatic kadanoff - baym - keldysh expansion in the local coulomatous interaction @x math0. on the one hand  , we establish the reliability of the snrg approach to quantum transport by comparing results for small values of @x Math0 to the diagramskadanoff-baym-keldyssh approach, which becomes exact in the limit @x maths1. however, on the other hand, we discuss discrepancies and reveal shortcomings of those diagrammatic approaches at intermediate values of the charging power.
stochastic geometry is a recently used approach for the analysis and performance evaluation of wireless  ( ad hoc as well as cellular ) networks.   this approach takes a macroscopic view of the network with the underlying assumption that all nodes in the network have identical statistical characteristics. in practice, due to randomness and heterogeneity in networks, nodes need to adapt to local spatial and temporal conditions  ( e.g., channel conditions and topology ) to reach optimum network wide performance. while the behavior of such distributed optimization protocols is often well understood on a given topology, there are usually no analytical characterizations of the statistical properties of the optimal state in large random and heterogeneous networks. in this work, we use stochastic geometry to study spatial adaptations of medium access control algorithms in aloha that aim at optimizing certain utilities. by modeling the network as an undirected graph  , we show that the spatial distributions of the expected utility and the spatial distribution of the actual utility can be computed for all types of utilities within the @xmath0-fair class using stochastically approximated poisson point processes. however, we are far from being able to identify a utility for which sto chastic geometry
the far infrared background ( firb ) is a well - known component of the cosmic microwave background ( cmb ), the galaxy, and the solar system.   we have used three different methods to separate the galactic emission from the isotropic firb in the firas ( far  infrared  absolute  spectrophotometer ) data. for the first method, we use the spatial variability of the galactic emissions as a template for the firb. for both the second and third methods,   the templates are the  line emission templates, which trace the atomic and ionized gas components of the interstellar medium ( ism ). for all three methods, we find that the model developed from the analysis of the diffuse infrared background experiment ( dirbe ) data provides a consistent result for the Firb.
the dynamics of a spinor bose - einstein condensation ( bec ) in an optical lattice is investigated by means of a set of spatially varying light fields giving rise to an effective spin - orbit coupling between the internal atomic states.   the effect is driven by two mechanisms, namely ; ( i ) bloch oscillations ( bos ) arising due to the tilting of the lattice and ( ii ) an intrinsic spin hall effect ( she ) deriving from the effective so coupling. being orthogonal to each other, these forces render a complex correlated motion of the bec in the potential. as a result  , the particular form of the so coupling renders dirac cones characterized by linear dispersions reminiscent of relativistic electrons. as an outcome of these, the evolution possesses as well a trembling _ zitterbewegung _ motion.
nuclear matter is a very interesting many - body problem in its own right.   it is defined as a hypothetical system of nucleons interacting without coulomb forces, with a fixed ratio of protons and neutrons, and can be supposed to be an idealization of matter inside a large nucleus. the starting point for any nuclear matter calculation is a two - body potential that models the nucleon - nucleon interaction. here   we review the history of nuclear matter calculations and present a new method for solving the infinite matter problem for dense asymmetrical nuclear matter based on the yukawa potential. by combining the properties of the deuteron and the observed phase shifts from scattering experiments  , we have obtained a unique nucleon-nucleon potential that matches the experimental bulk properties of density - dependent nuclear matter.
cataclysmic variables ( cvs ) are nonmagnetic stars with high mass accretion rates that have been detected in the uv resonance lines of ss  cygni ( @xcite ).   we present two - dimensional isothermal hydrodynamic models of line - driven accretion disk winds ( ldadw ) in cvs, which show that the terminal velocities of the winds are approximately independent of the luminosity of the disk, although increments in luminosity produce increments in mass - loss rate. for a typical white dwarf mass of @xmath6 ( @xaite )   the wind velocity is approximately half the terminal velocity and the absorption occurs in the enhanced density region where density is increased relative to a spherically diverging wind with the same mass loss rate and the velocity is roughly half the terminus.
the o@xmath1 loop model on the square lattice is a two - dimensional lattice model with local interactions.   it is exactly solved by means of the bethe ansatz, with periodic @xcite and open boundaries. as an integrable model,   its underlying @xmath2-matrix is that of the izergin - korepin,@xcite or @x Math3 vertex model. for some path across a domain  , it is known that the parafermion satisfies the condition of discrete holomorphicity, i.e., it satisfies the boltzmann weights on each vertex. here   we discuss the recent developments in the study of this model in terms of the yang - baxter integrability.
we evaluate the @xmath25 leading order ( lo ) contributions to the r.h.s.   ( [ approx ) decay rate that originate from @x math26 with @x Math6. in the present paper, we also evaluate the contribution of the qcd penguin operators to the same process. for each of the four - quark operators,   the decay rate is approximated by its perturbative counterpart  ( |b x_s ) _ e _   > e_0 ( b x^p_s ; x = 0.1 ), where @x maths11 stands for@xmath12 partonic states, where no charmed hadrons appear in @xMath13 by definition.    the results are compared with those of previous work at the next - to - next- to - leading order level and show that the current - current operators do not only contribute to the decay but also generate a large number of corrections which are larger than the ones that arise from the ckm - suppressed transitions.
the pulsar gx  1 + 4 is an accreting x - ray pulsar with a symbiotic red giant optical companion, v2116 oph.   the pulsar was discovered in 1970 and has been known for more than 40 years as a pulsar of the fastest spin - up rate among the known at the time ( @xmath4  s / s ). here   we combine all measurements that we are aware of from the literature with the pulse periods determined from bepposax / wfc, integral / isgri, fermi / gbm and fermisgri data which span a time period of about 40 years giving us a unique insight in the pulse period evolution of this symbiotic x - rayspulsar. to obtain this result   it is necessary to combine these measurements with the previously reported pulse periods obtained from other sources such as exosat, bielefeld   lewin and riemann   hochberg experiments.. the main result obtained during this work is the plot shown here which currently is the most updated and complete series of pulse periods of gx1 + 4 [ gxhistdata [ g
supersymmetric models of supersymmetry breaking and its mediation have been the most promising candidate of physics beyond the standard model.   however, recent progress in astrophysical observations and theoretical calculations such as the measurement of the matter density of the universe and big - bang nucleosynthesis constraints on the gravitino abundance   @xcite put a threat to many supers asymmetric models. at the same time, these are new strong hints which guide us to the true theory. in this paper  , we find that a simple model of gauge mediation actually provides us with a viable and natural scenario for cosmology and phenomenology.
radio jet bases ( " radio cores " ) of blazars have been considered to be opaque photospheres against synchrotron self - absorption or free - free absorption.   we performed 12 epochs of astrometric observations of the large x - ray flare of markarian  421 in 2011 september @xcite using the vlbi exploration of radio astrometry ( vera ) at 22 ghz together with a nearby reference source j1101 + 3904, which is listed in the very long baseline interferometry ( vlba ) calibrator survey list, as a position reference. during these observations,   the apparent inward motions of the jet component relative to the radio core were observed at more than @xmath610 ghz@xcite by the whipple ground - based cherenkov telescope and the japanese vlbio network. for the first time, we show that these apparent outward motions are not due to outflowing jets, but are due to the position of the central radio core, which changes its position along the jet after the flaring event.
the study of consciousness has received much attention in the field of artificial intelligence, which attempts to imitate and simulate intelligent activities using a machine.   although traditional approaches for studying consciousness have included neuroscience @xcite or neural network modeling, it is demonstrated that a quantum system to be presented below necessarily involves a conscious, as opposed to a physical, activity of an observer observing the unitary dynamics of a quantum state. based on this observation, a particular quantum computer can be built such that it yields a computational model involving consciousness. using logic similar to that in turing s haling problem, it can be shown that this computational model necessarily runs into a contradiction. as a result,   the computability of consciousness is shown to be non - computable. because consciousness is a phenomenon experienced by an observer, representation of consciousness as a computational process will be attempted and its computability will be examined.
we present the results of numerical simulations of the dynamics of strong - field recombination in ultrastrong laser fields for two model one - dimensional systems : a rectangular potential well and a long - range coulomb - like.   we examine the time dependence of the population of the bound state population ( initially equal to zero ) and its dynamics, which are both dependent on the amplitude of the laser field and the slow drift of the kramers - henneberger well. during the recombination an initially free electron modeled by a gaussian packet, intially resting at twice the amplitudes of classical free oscillations, is carried towards the ion in the laser force field. using the crank - nicholson scheme we solve the time - dependent schrdinger equation in one spatial dimension. as the measure of efficiency of recombination we take the final population of all the electrons in the atomic bound state.
we report on inelastic magnetic neutron scattering experiments on @xmath0 at various temperatures.   we have investigated the 4f magnetic response for samples with sr   concentrations@xmath1 and nd  concentrations @x Math2 at low energies ( typically @x math28 ) in order to obtain information about the cu magnetism in the @xMath6layers via the nd - cu interaction. using the time  of  flight ( tof ) spectrometers v3 neat@xcite ( hmi berlin ), g6.2 mibemol ( llb saclay ) and in5 ( ill grenoble ) we have performed temperature dependent studies on samples with high @x maths1 and low @x mathematics2 concentrations using the monochromatization of the incident neutrons with a single crystal of /nucleotides of -n = 0.2(sr+/nd+ ) or =0.15(sr)/nod(nod+ ) at different temperatures. from these experiments we have found that the quasielastic lorentzian is observed in the
electroproduction of mesons in the deep inelastic scattering ( dis ) is a modern tool which permits to study the structure of the nucleon on the partonic level.   it is supposed that the excitations of nucleon resonances dominate in electroproduction. here   we show that the @xmath23 dependence of the differential cross section @x Maths23 depends on the contribution of the exlusive - inclusive pion charge form factor   @xcite, which is well described by the quasi - elastic@xmath11 knockout mechanism at jlab and at hermes. for the nonvanishing transverse part @x math23,   the role of the excitation of the pion resonances is also well described.
the crossing of observational data from high redshift supernovae of type ia ( sne ia ), cosmic microwave background ( cmb ) radiation, matter power spectra, x - rays from clusters of galaxies, and weak gravitational lensing strongly suggests that the present universe is dynamically dominated by a dark sector which is responsible for about @xmath0 of its total energy content.   it is usually assumed that this dark sector has two different components : ( i ) dark matter, which is supposed to consist of weakly interacting massive particles ( wimps ) with zero effective pressure and ( ii ) dark energy, a mysterious entity which is equipped with a negative pressure. in this paper   we explore to what extent a viscous fluid can provide a unified description of the dark sector of the cosmological universe. using an adiabatic perturbation analysis for the homogeneous and isotropic background dynamics, we show that the existence of a bulk viscous pressure can be traced back to a non - standard self - interacting force on the particles of the viscosmic medium under the conditions of spatial homogeneity and isotropy. as a result  , we find that the observed matter power spectrum
we present a numerical method for calculating entanglement entropy ( ee ) in a one - dimensional ( 1d ) free fermi gas with a single potential scatterer embedded in the system.   we show that the single impurity introduces a term on the order of @xmath0 to the ee, which is inversely proportional to the subsystem size. by considering certain limiting cases, where analytic treatment is available,   the origin of both terms are identified by considering the subleading contributions to ee and the influence of the impurity on the wavefunction as well as the quantum state of the system.the results are verified numerically in the scaling regime for a discrete lattice system.
time reversal invariant ( tri ) superconductivity has attracted great interest in condensed matter physics recently.   however, there is no consensus on the presence of tri topological superconduction in any known system yet. in this paper   we present the theoretical evidence that the n - type doped single bilayer bi(111 )   bilayer hydride / halide ( bih ) is a tri topology superconductor. using a tight - binding model of the band structure of bih, we show that the electron correlation by the intra and inter - orbital coulomb repulsion@xmath3 and the hund s rule coupling @xmath4 is the dominant pairing channel for the bih near the fermi energy. upon electron doping,   the interaction between the two channels is replaced by a mean - field pairing instability analysis which predicts the dominant pairwise pairing channel as @x Math5 and hence leads to a triTopological superconducting state.
we predict that bulk - like epitaxial films of at least six non - magnetic metallic elements show first - order martensitic transitions upon variation of the epitaxia strain.   the transition is due to a discontinuous dependence of intrinsic film properties on the interface lattice parameters of the substrate - film interface, and this dependence is not restricted to certain structures, compositions, or ground states. in particular, we find jumps in the lattice parameter of la by about 20% in the case of ferromagnetic tetragonal ( bct ) films with four - fold surface symmetry and body - centered tetragonally oriented ( 001 ) substrates.
we present a method for the reconstruction of the coronal magnetic field from photospheric line - of - sight magnetogram data using linear force - free fields.   the method is based on the assumption that the current density in the solar corona is force- and/or potential - free, and which optimises the value of the force -free parameter @xmath0 in such way that the resulting field fits the three - dimensional shape of a coronal loop by minimising the deviation of the reconstructed magnetic field lines from the observed loops.the proposed method is tested using the loop shapes deducted by from applying dynamic stereoscopy to the solar active region noaa 7986 using soho / mdi and soo / eit data taken on 29, 30 and 31 august 1996.
the vlti is the only long baseline interferometer below the equator.   it provides both the sensitivity and the angular resolution necessary to detect the radial variations of a sample of classical cepheids, to be used to calibrate the zero point of the period - luminosity ( p - l ) distance relation, and to provide the high quality data necessary to apply the geometric baade - wesselink ( bw ) method. in marengo   @xcite ( mm02 hereafter ) we describe a new approach to compute detailed wavelength- and phase - dependent limb intensity profiles for pulsating cep heids.. our profiles are based on time - dependent, non - lte hydrodynamic computations which, starting from a model of the cepheid pulsation, reproduce the dynamic structure of the stellar atmosphere as it pulsates. from these model atmospheres, we obtain the intensity emerging from the stellar photosphere ( and thus the limb darkening ), computed for each pulsational phase relevant to the interferometric observations.    this procedure can be applied to all cep Heids for which a reliable pulsational model is available.,mm02 is available at
we present a systematic scheme for the in principle exact computation of all possible current cumulants in markov dynamics satisfying local detailed balance.   the algorithm is based on an identity between current and activity fluctuations, connecting the time - antisymmetric with the time- and space - symmetric fluctuation sector as is typical for a dynamical large deviation theory in nonequilibrium systems. here   we focus on the mechanical aspect of the method, how it can be seen as a modified rayleigh - schrdinger expansion with specific computable expressions of thecumulants.. its relevance is therefore in reliably producing also higher - order cumulant that can then be further analyzed for understanding the physics of some particular model.
nonparametric estimation of unknown densities on partially or totally bounded supports, with or without correlation in its multivariate components, is a recurrent practical problem. because of symmetry, the multivariate classical or symmetric kernels, not depending on any parameter, are not appropriate for these densities.   in fact, these estimators give weights outside the support causing a bias in boundary regions. in order to reduce the boundary problem with multivariate symmetric kernel as gaussian, @xcite and recently @xcites have proposed adaptive full bandwidth matrix selection ; but the bias does not disappear completely. in the present paper  , we introduce some multivariate associated kernels with the most general bandwidth matrix. in other words, the support of the suggested associated kernels coincides to those of the densities to be estimated ; also, the full bandwidth matrices take into account different correlation structures in the sample. by unbiased cross validation method,   the choice of the optimal bandwidth matrix is shown to be based on the best combination of least squares and unbiased cross - validation. using simulation studies and a real data analysis of electoral behaviour of a population with regard to a candidate, the role of forms of bandwidth Matrices is explored in details.
a football pattern is a graph embedded in the two - sphere in such a way that all faces are pentagons and hexagons.   if one requires that there are exactly three faces meeting at each vertex, then euler s formula implies that the pattern consists of @xmath0 pentagon and@xmath1 hexagon.    we prove that these are the only generalised football patterns on the two- sphere, and show that the classification theorem for spherical football patterns proved in the first part of this paper for the triple @x Math10 actually holds for all general organised football patterns with @x maths11.. however, football patterns from higher genera always admit branched covers of degree at most @x math6 which in turn are also brancched covers of the standard spherical football.
we present a new method for finding a common fixed point of the composition of finitely many firmly nonexpansive mappings in geodesic spaces.   the method is based on the asymptotic behavior of the proximal point method and is extended to riemanninan manifolds by considering the case of a finite family of maximal monotone operators which are defined on a space of nonpositive curvature in the sense of alexandrov ( also known as cat@xmath5 spaces ). using this method,   we show that the sum of the distributions of the convex lower semicontinuous functions of two proper convex semi - continuous functions can be obtained weakly to a fixed point when the fixed point set is nonempty.
the cataclysmic variable mct 2347 - 3144 ( v1193 ori ) is a subluminous blue star with a period of 0.277d or 6.65h with a semi - amplitude of 0  0.144 mag.   the ccd photometric unfiltered observations were taken with the 1 m telescope at saao during 4 consecutive nights in 2002 and 3 nights in 2003. after the same standard procedures and period analysis of the 2002 light curves we were able for the first time, to photometrically confirm the orbital period of this object by using the folded data obtained from the 2002 observation run. however, we were not able to detect the periodicity in 2003 when the system s mean magnitude appeared to have increased by 0.4 mag.
during the hierarchical process of structure formation, supersonic gas infall and merging events invariably generate powerful, large and long - lived shock waves.   these should produce copious amounts of relativistic crs, by way of diffusive shock acceleration, including both electrons and ions. in addition, the post - shock gas and diffusively trapped crs are mostly advected into non - expanding regions, such as filaments and clusters. it turns out that the energy of most of the cr - protons is only marginally affected by radiative losses during a hubble time, so the possibility that the latter might accumulate inside forming structures, storing up a substantial fraction of the total pressure there, is discussed.
dynamical friction is the reaction force that a perturber feels from the gravitational wake it generates in the ambient medium.   the derivations of dynamical friction for collisionless systems assume that the perturbers motion is uniform and that the force is proportional to the square of the pertuber s mass. when acceleration is taken into account, the amplitude of the force increases with respect to the value derived assuming a constant velocity. here  , we show that the effect of acceleration is independent of the type of motion and is non - local as it depends on the trajectories of the accelerating perturbs. by taking into account the acceleration of the accelerating perturbered system,   we derive a new expression of dynamicals friction that applies to all types of motion but not to the density perturbation. using this new expression, we find that the initial velocity of the accelerated perturbing system is the only variable that can affect the dynamical tension between the two states of the gravity.  also, the magnitude of the torque generated by the acceleration does not depend on the density enhancement near the pertuber but on the velocity of its wake.
recently, mannhart and moler have observed spontaneous generation of delocalized magnetic flux in asymmetric @xmath0 grain boundaries in yba@xmath1cu@x Math20@x math3 ( ybco ) twin boundaries.   they have explained the existence of this flux in terms of a superconducting order parameter having @x maths4 symmetry and grain boundaries which are faceted. here   we present an alternative physical model for the superconductor, which also leads to spontaneous flux generation in these twin boundaries, and which could thus account for the experimentally observed behavior.
this article is a reprint of the original work by the third author of this paper on the simplex method by victor klee and minty, published in 1972.   the first part of this essay is a recollection of a visit to klee at the university of washington ( seattle ) in august 2000 where he asked him if he thought the simpleX method was polynomial. The second part is a re-read of the classic paper by klee that deals with the number of iterations that may be required in the worst case to solve a linear program ( lp ) by dantzig s simplex algorithm.. the third part is an account of a meeting with klee in seattle in april 2000 when he asked the author if he thinks the simple x method is polynomials.
we develop a theoretical model for the generic type of experiments, where particles scatter in pairs into two well - separated regions.   we derive the bogoliubov equations governing the dynamics of pair formation, and applying the bloch - messiah reduction @xcite, we write the state in terms of pairs of independently squeezed modes. using the same formalism, we calculate the density and the number of scattered atoms, and the two body correlation between them. to demonstrate the presence of ideal number - squeezing between the opposite regions, violation of the cauchy - schwarz inequality and, using the fisher information criterion known from quantum metrology, we show that the atoms from the twin - beam system are entangled.graphical abstract
we revisit the model proposed by petraki, trodden and volkas in  @xcite, in which the asymmetries in the dark and visible sectors are produced during a strong first order phase transition, in analogy with the electroweak baryogenesis mechanism.   we calculate the strength of the phase transition and find the stochastic gravitational wave background in terms of the underlying parameters of the model. at the lhc, we also investigate other relevant signals, i.e., constraints from halo ellipticity due to dm self interactions, @xmath1 and direct detection prospects.
a density - matrix - based algorithm named feast for hermitian eigenproblems of this kind has been proposed by polizzi in 2009.   the main building block of feast is a numerical - quadrature computation, consisting of solving independent linear systems, each for multiple right hand sides. here  , we show that the feast algorithm can be understood as a subspace iteration accelerated by a non - adaptive accelerator @xmath18 for all@xmath12 where @x Math6 approximates the spectral projector to the invariant eigenspace in question. when chosen appropriately, this accelerator can accelerate the convergence of feast at a rate that is faster than that of the direct solver  . however, there is no theoretical study available on the conditions under which feast converges, and if so, at what rate.
we survey the geometric properties that cause stochastic incompleteness to occur for the minimal diffusion process associated with a laplacian on manifolds and graphs.   we draw heavily from the survey article of a. grigoryan @xcite for the case of riemannian manifolds, and then present some recent results for graphs. in particular, we give examples of stochastically incomplete graphs with only polynomial volume growth.
we theoretically propose and study a model belonging to a particular symmetry for phase transitions in both symmetric and asymmetric inhomogeneous membranes.   our model is a reduced model, in which the bilayer nature is not kept explicitly ; instead it is replaced effectively by an inhomogenous single layer for simplicity. depending upon the bending modulus of the composition field that describes the inhomogeneity of the asymmetric membrane in our model,   the model may display ( i ) both first and second order phase transitions through a critical point ( cp ) and a tricritical point ( tp ), and ( ii ) a third order phase transition through a second order cp and a fourth order tp. using perturbative renormalization group methods, we calculate the universal scaling exponents that characterize the cp and tp in the model. unlike more commonly used linear curvature - composition coupling @xcite, our model involves non -linear curvature-composite coupling belonging toa particular symmetry. since any purported effects of asymmetry are likely to depend on how asymmetry affects the system free energy, we hypothesize that the model predicts  generic nontrivial enhancement  of fluctuations near the tp and cp
the use of novae as distance indicators poses more problems than that of other methods based on variable stars.   we have used the expansion parallax data from a survey of nova remnants to derive maximum magnitude - rate of decline relations, based on the standard light curve parameters @xmath4,@xmath5 and @x math6, and also studied the distribution of minimum magnitudes. using these relations, we found that the minimum magnitude of the relation is generally smaller than the maximum, with the exception of the 2200   band, where it is larger than the maxima. in the case of the latter,   the difference between the minimum and maximum magnitudes is not statistically significant.
quantum teleportation is a powerful tool for quantum computation.   it enables the remote transmission of the state describing a quantum system to another one, without ever knowing the state, and it also allows the construction of a new way to perform quantum computation @xcite. in this contribution   we show that the features of the multi - entanglement protocol ( mtp ) of ref. [ bennett et al. :   j.@xcite, 2012 ] are not restricted to the klm teleportation scheme. in order to show that we build in sec.     a similar protocol ( protocol @xmath1 ) without relying on the intricacies of theklm scheme, we use the same language of the original bennett _   _ proposal @xficite, which allows us to express @x Math0, the total probability of getting unity fidelity outcomes, as a function of the number of teleportations and of the shared entanglements between alice and bob. here, we present two new protocols ( protocols @x maths2 and @x math3 ), both of which are more efficient than the previous one. at each successive run of the mtp
we investigate the general properties of astrometric double lensing events and estimate and compare the detection probabilities of detecting double microlensing events from both photometric and astrometry observations.   we show that the chance for the source trajectory to enter the astrometrically effective lensing region of the companion will be larger if the photometric effect endures to a large lens - source separation, and thus the probability of detecting astrometrical double lensed events will also be larger. by using analytic expressions for the relations between binary lensing parameters to become photometrically effective and astromaetric double lensesing events, we estimate the detection rates of these events by comparing the centroid shift trajectories and the light curves of events caused by an example wide separation binary. in this paper, we summarize new findings from the previous and current searches of the space interferometry mission data set @xcite.
in mri, images are reconstructed from acquisitions of corresponding fourier expansion coefficients in k - space, where the side lobes of the sinc result in oscillations ('ringing') in the neighborhood of sharp edges.   the strength of the ringing in the reconstructed image depends on the precise location of the edge relative to the sampling grid, i.e. how the underlying sinc - function is sampled at its extrema or at the zero - crossings. here  , we present a non - iterative method for the correction of ringing artifacts in mri images by finding the optimal subvoxel - shift for pixels in the vicinity of the sharp edges in the image. as there are multiple edges in an image, the correction can not be achieved by a single, global shift, but must be performed on a local basis. using a simple absolute differences approach to measure the oscillations,   we show that the ringing artifacts can be reduced by selecting the smaller value of the optimal shift for each pixel in the region of the image which minimizes potential oscillations in the surrounding neighborhood.
we investigate the relation between the filamentarity observed in the galaxy distribution and ongoing star formation activity in the galaxies.   our analysis is limited to seven thin strips on the sky drawn from the sloan digital sky survey dr5 @xcite, each spanning @xmath6 in the r - band absolute magnitude range @x Math6 and redshift range@xmath12. for all the lines,   the galaxies are classified as either star forming ( sf ) or galaxy non - forming ( agn ). using a cosmological model we show that the degree of filamentarity found in the distributions of the galaxies is dependent on the luminosity, colour and morphology of the galaxy. here   we find that the extent of filaments is found to be statistically significant up to length - scales up to ~1.5 billion light - years and then decreases with increasing galaxy density.    we also find that both the sf and agn galaxies show strong emission at the redshift of ~2.5bnj / cm2 which is consistent with the results of our earlier work ( @xaite, hereafter paper a ) where we showed that filamentarity is influenced by other galaxy properties like luminosity
the evolution of the magnetic field of a neutron star ( ns ) is studied in a population synthesis model.   the results show that the mass - shedding instability limit for the lifetime of the accretion phase is set at ~2.5 ms, which is well within the range of the observed period of ~1.5 to 2.0 ms for the proton fluxoids and ~3msec for the protons. by using a monte carlo simulation of the population synthesis models, we show that this limit is due to the existence of a superconducting core with a very conducting transition shell and a crustal magnetic field.
we report here a large set of binary - star measurements made at the 4.1-m southern astrophysical research telescope ( soar ) with the speckle camera.   the primary goal is improvement of known orbital elements and determination of new orbits. by resolving known binaries with astrometric acceleration @xcite or variable radial velocity ( rv ), we obtain estimates of their periods and mass ratios and lay a foundation for future orbit determination. in this paper   we also observe _ hipparcos _ binaries within 200pc with southern declinations, so far largely neglected. these observations allow us to evaluate orbital motion and to find a subset of " fast movers " for further monitoring.
we perform a cross - correlation study of the wilkinson microwave anisotropy probe ( _ wmap ) first - year data and the energetic gamma ray experiment telescope ( _ egret ) diffuse gamma - ray intensity map in wavelet space to probe the origins of potential residual foregrounds possibly induced by cosmic rays.   the results show that the two maps are highly correlated at the angular scale of 0.1, 0.2 and 0.3 hz, and that the overlap between the two sets of maps is very small.    the influence of the source of the observed overlap is explained by the fact that the signal - to - noise ratio enhanced maps are dominated by galactic foregrounds as well as extragalactic point sources, which are separated from the underlying cmb signal by the frequency - dependence property of the foregrounds. for the first time  , we have used the wavelet approach to investigate the origin of the apparent deviations from the original data on the basis of the integrated sachs - wolfe effect ( isw ) of the cmb data using the egret map as a local tracer. with the help of the x - ray diffraction method, we find that the
the superfluid hydrodynamics equations can be expanded in powers of low velocities and one safely uses the first nontrivial terms of this expansion.   nevertheless, there is a number of experiments@xcite where this is not enough. in some of them   the superfluid flow is studied in small orifices. in these circumstances the maximum velocity is inversely proportional to the orifice width and may reach the order of the landau critical velocity if the aperture is small enough. here   we use scaling speculations to find critical behavior of the critical velocity in the vicinity of the @xmath0-point.
the sdss is a digital photometric and spectroscopic survey of the northern galactic cap.   it will cover one quarter of the celestial sphere in the north galactic cap and produce a smaller area ( @xmath0225 deg@xmath7 ) but much deeper survey in the southern galactic hemisphere. here   we discuss the matching of early sdss data with those from the 2mass and first surveys. for about one million brightest galaxies and 100,000 quasar candidates  , we find that the position of an object in sdss color - color and color - magnitude diagrams can be efficiently used to constrain its nature. for most of the unresolved sources,   the majority of these objects are on the main sequence, and the modeling of the stellar populations observed by sdss indicates that 99% of these stars ( 99% ) are on this sequence. at the same time, the presence of low - redshift quasars has been shown to be associated with the location of many of the resolved sources.
chiral symmetry is believed to be a fundamental symmetry of qcd.   however, this symmetry is spontaneously broken at low temperatures and chemical potentials by a finite expectation value of the quark ( or chiral ) condensate, @xmath2 per light quark flavor in vacuum. at higher temperatures,   the symmetry is expected to be restored as the values of the condensates approaches zero. here  , we simultaneously analyze the in - medium vector and axial - vector spectral functions in vacuum using an extended model which combines a microscopic@xmath5 spectral function with breit - wigner anstze for the @x Math6 and the first excited states.    this model is quantitatively constrained by both the experimental @x math3-decays and the weinberg - type sum rules.. novel features of our analysis include the study of excited states and the post - quark post - decay state of the first quark.
we investigate the structure of equilibrium gels in binary and ternary mixtures of patchy colloidal particles.   we find eight fundamentally different types of percolated states that we classify according to their strength against breaking bonds, i.e., bigels, trigels, tricontinuous gels, and mixed gels. for each type of gel,   the number of patches is a key ingredient determining the location of the liquid - gas critical point. by comparing theoretical with monte carlo simulation results, we show that the latter agree semi - quantitatively with the theoretical predictions of the flory - stockmayer theory of polymerization  @xcite. additionally, we observe the occurrence of strong gels such as bigels and trigels provided that the intraspecies bonds are stronger than the interspecies ones.
we investigate the adiabatic cooling of the blast wave dynamics of a gamma - ray burst ( grb ) with a long - lived reverse shock ( rs ) in the ambient medium.   we use the semi - analytic formulation of relativistic blast wave, presented in @xcite ( hereafter u11 ), which takes into account the conservation laws of energy - momentum tensor and mass flux to the blast region between the forward shock ( fs ) and the reverse shock that are " connected " through the blast via the relevant physics laws. for a general class of grb problems with a short - lived rs or with a longer rs, for which the fs dynamics should deviate from the self - similar solution of@xcite  , u11 provides an accurate numerical solution by taking into account both the radial stratification of the ejecta flow and the density structures in the circumburst medium.
the description of strong electron correlation effects is still a challenging problem for both density - functional theory ( dft ) and wavefunction theory ( wft ) communities.   one way to overcome the double counting problem consists in separating correlation effects in the coordinate space, as initially proposed by savin   savin. in this work   we propose to revisit this separation at the formal level by using orbitals occupation as basic variable rather than the electron density as the basic variable. here  , we show that the theory is derived for a particular choice of orbitals, namely those obtained by diagonalizing the non - interacting hamiltonian ( kinetic and nuclear potential energy operators only are considered).the theory is then used to model the ground state of a single - configuration dft model of a dissociated molecule with an orbital - occupation number larger than @xmath0. the experimental results show that it is possible to derive the theory for a set of molecular orbitals with an occupation number greater than @Xmath0 without losing the universality of the complementary density functional.
in this work, we prove fundamental properties of random apollonian networks ( rans ), a popular model of planar graphs with power law properties.   the model is derived from the kronecker model for the web graph @xcite and is characterized by skewed degree distributions, large clustering coefficients and small average distances. in particular, we show that the proportion of vertices of a given degree follows an approximate inverse power law, i.e., it is approximately 1/2 of the total vertices at time @xmath2. using theorem    we relate the highest degrees and eigevalues of the model to the largest eigenvalues of the adjacency matrix of the random graph at time@xmath15. also, we demonstrate that the diameter of the network satisfies in probability the unique solution greater than 1 of the equation @x Math12.    our results are compared with those of several other models of rans, including the aiello - chung - lu model, the cooper - frieze model and the protean model.
we investigate how the size of critical mass within a group affects the opinion formation in a majority rule model of opinion formation.   our model is based on a population of agents situated on a square lattice with periodic boundary conditions, where each agent is selected at random and with it a surrounding local - influence group of other agents. if the majority opinion exceeds a critical value, all agents in the local - control group are allowed to adopt the majority opinions.    if the threshold value exceeds a certain threshold, the system will not reach consensus. as a function of the relaxation time, we find that the number of agents who share the same opinion increases with the increase in the critical mass ; however, this increase is dependent on the interaction network topology and the concentration of the groups. for small - world networks with strong degree heterogeneities or with community structure,   the magnitude of the threshold does not affect the efficiency of the system to reach consensus, and if so, how it does so.
the arecibo galaxy environment survey ( ages, @xcite ) is a new hi blind survey carried out with the alfa multi - beam system.   it aims to study the atomic hydrogen properties of different galactic environments to faint sensitivity limits ; low hi masses ( 6@xmath4, assuming a 200 velocity width at 92.8 mpc, the distance of the abell cluster 1367 ) and column densities of @xmath1 3@x Math5 ( for a source that fills the beam ). here   we report on the early results obtained from observations of a subset of the whole ages - a1367 region : a @x math7 square degree area centered on the cluster core. in may 2006 and april 2007, we observed the entire abell 1367 region using the 305-m arecibio telescope at the time of the first phase of the ages project. during the observation period we measured the density of neutral hydrogen and molecular hydrogen in the region by means of high - resolution blind hi blind surveys at wavelengths ranging from 0.01 to 5.5 arcmin.    the results show that the density was very low at all redshifts studied so far.
the discovery of quasars in the early sixties led to the development of a number of hypotheses to explain the existence of black holes in active galaxies.   one of these is the hypothesis that the accretion of surrounding matter onto a black hole drives the emission of high - energy x  ray and @xmath1ray radiation from the nucleus of an active galaxy, which is thought to be the primary source of energy in many cases. while this is a viable and very attractive paradigm, only the last few years have brought a solid evidence for it, allowing also to measure the mass of the central object. here  , we review the observational evidence for the presence of blackholes in agn, and discuss the effects of the orientation of the accreted accretion disk surrounding the back hole on the appearance of the nucleus. by contrast, we discuss the observations of the jet - dominated agn known as blazars, which show no signs of nuclear activity, but do show evidence for such black holes.
we construct a general statistical mechanical formulation for studying low reynolds number swimmers that undergo conformational changes in a stochastic manner pertinent to systems of molecular scale.   we attribute transition rates to each deformation move or swimming stroke, and calculate the propulsion velocity as a function of these rates. using the three - sphere swimmer model as an example  , we show that the proposed formulation can be applied to the design of self - steered small scale swimmers.
the presence of extremely red objects ( eros ) in the near - infrared ( @xmath55 ) population of galaxies has been confirmed by near - ir and optical spectroscopy.   the red colors of eros are consistent with two classes of galaxies : they could be old, passively evolving elliptical galaxies at@xmath10 which are so red because of the large @x Math7correction, or they may be strongly dust  reddened star  forming galaxies or agn. on the other hand, some eros have been detected in the sub   mm range, thus providing examples of high  redshift starburst galaxies reddened by strong dust extinction and characterized by high star formation rates. here   we review the results of the last few years concerning the composition of the ero population, focusing on the surface brightness profiles of these galaxies.    we find that the surface density of many eros is significantly lower than expected based on the current models of galaxy formation, as well as on the observations of a small fraction of low - mass - stars and brown dwarfs among eros. to test these models, we use a new method for the detection of very redshift galaxies in the
spatial econometric models have been widely used in many areas ( e.g., economics, political science and public health ) to deal with spatial interaction effects among geographical units.   the aim of this paper is to investigate the quantile regression approach for partially linear varying coefficient spatial autoregressive models by employing b - spline for the approximation of varying coefficients. due to the presence of endogenous variable  , we employ the instrumental variable quantile regressions ( ivqr ) method to attenuate the bias in the estimation of the varying coefficients ; however, the results show that the proposed estimators are not able to estimate the conditional quantile curves without any specification of the error distribution. asymptotic properties of the estimators and test statistics are also discussed.
the galactic globular clusters ( ggcs ) are the oldest fossil records of the formation history of our galaxy.   they are made up of a single population of stars, all born at the same time, in the same place, and out of the same material. as a first exploitation of this new data base,   we have conducted a ggc relative age investigation based on the best 34 color - magnitude diagrams of our catalog, showing that most of the ggc stars have the same age. here  , we describe the observations collected at the 91 cm european southern observatory ( eso ) / dutch telescope during two runs in 1997 with the 1-m class telescopes, i.e. the 1 m isaac newton group / jacobus kapteyn telescope ( jkt ) and the 9.5 m europeansatome telescope ( eeso ). from these observations, we have obtained the data for 52 of the 69 known ggccs with the @xmath10 telescope, and the remaining ones with the dutch one. using the data from these two runs, we developed a data base of the metallicity indices of the
the kinematic dynamo effect is generally believed to be facilitated by a separation of spatial scales between the flow and the magnetic field.   this idea has its roots in the discovery of the @xmath5-effect for non - parity - invariant flows, which can be demonstrated by asymptotic theory involving, in principle, very large scale separation. here  , we investigate the genericity of the phenomenon of negative eddy diffusivity and the lowering of the critical magnetic reynolds number for a series of time - independent three - dimesnional flows with large or moderate scale separation ( one instance of which is the modified taylor  green flow ) that can amplify a large - scale magnetic field by a negative eddiness mechanism.
resonances are a phenomenon, which occurs often in physics and can be easily understood heuristically. nevertheless, studying it mathematically rigorously is more difficult.   the resonance asymptotics on non - compact quantum graphs were first studied in @xcite, where it was observed that some graphs do not obey expected weyl behaviour and a criterion for distinguishing non - weyl graphs with standard coupling has been obtained. in the current note   we continue in investigating this problem and illustrate the main results of @xaite on several simple examples with standard coupled quantum graphs. in particular, we focus on the pseudo orbit expansion and explain to the reader in detail how to construct the resonance condition by this method.
we investigate the possibility of the existence of soliton - like solutions for two interacting bose - einstein condensates.   we show that in such coupled equations set ( describing two interacting bec s ) regular solutions appear. from our point of view such solutions   describe either defect or a droplet created by two interacting boson s.
the spin electromagnetic field drives electron s spin, and thus plays essential roles in spintronics.   there is a gauge field for this field, a spin gauge field, which couples to spin current of the conduction electron. as we shall see, when a spin - polarized electric current is applied, the adiabaticspin gauge field leads to spin - transfer torque and moves the magnetization structure ( sec.  ).. the world of spin electromagnetic fields is richer than that of electric charge, since the electron s Spin in solids is under influence of various interactions such as spin - orbit interaction.    we shall show that even magnetic monopoles can emerge from the spin electromagnetic Field.
the bootes deep field is a radio survey covering @xmath276  in the 2df qso redshift survey.   it covers a large area of the sky with a broad redshift distribution, and has been used to select optically - selected starburst galaxies for the local universe using the iras method. at this time,   the optical - selected galaxies are unbiased tracers of mass, following a spatial correlation function of the form@xmath6, with @x Math7  and @x math8. here   we measure the clustering of the cluster of these starbursts by comparing the results with those of the extremely red objects ( eros ), the dusty, star - forming eros at @x maths14, and the radio - loud galaxy population ( agn ), which is the dominant population below a few 100@xMath22jy. we find that the ~1.4  ghz agn is more strongly clustered than the ~2.5  hz eros, and that the clusters are due to the size distribution of multi - component radio galaxies, rather than to the mass distribution of the galaxy itself. as the redshift increases, the cluster
on august 24, 2002, active region ( ar ) 10069 was near the western limb of the sun ( w81 ) when it produced a powerful ( x3.1 ) flare associated with a fast and wide coronal mass ejection ( cme ).   this event has been well studied due to extensive observations remotely by soho / lasco and soho - uvcs @xcite as well in - situ by the _ wind _ and _ ace _ spacecraft among others and also its inclusion as one of the solar heliospheric interplanetary environment ( shine ) campaign events. here, we study the deflection of a cme in the corona and in the heliosphere during this event using a new and realistic model of solar eruptions associated with an accurate model of the coronal magnetic field. based on the simulation,   we find that the cme span and deflection are significantly different between the two events : the first one was much larger than the second one, but the differences are not statistically significant.
the van der waals and casimir interactions of graphene deposited on a substrate with a material plate made of an ordinary material at room temperature are computed using the polarization tensor of the electromagnetic fluctuations on graphene expressed in terms of the electric susceptibility ( polarizability ) of graphene and components of the density - density correlation function.   the results are compared with those obtained using the random phase approximation of the lifshitz theory, where the reflection coefficients of the resonant electromagnetic oscillations are expressed via the polarization Tensor in ( 2 + 1)-dimensions.. the results show that the longitudinal version of the differential equations for the van derwaals and Casimir interactions between two graphene sheets and the material plate is more accurate than that derived from the random - phase approximation.
the fractional calculus of variations is a new area of research that extends the classical variational calculus by considering fractional derivatives into the variational integrals to be extremized.   this occurs naturally in many problems of physics and mechanics, in order to provide more accurate models of physical phenomena. in this paper  , we introduce the fractional caputo - type derivative @xmath0, which is a convex combination of the left caputo fractional derivative of order @x math1 and the right caputo fractions of order@xmath2. using this derivative, we can describe a more general class of variational problems, including multiobjective problems. knowing the importance and relevance of multi objective problems of the calculus of variation in physics, engineering, and economics, we trust that the results now obtained will open interesting possibilities for future research.
we propose two axiom - aware model - based planners called asplan and iplan, which are based on answer set programming ( asp ) and integer programming ( ip ) respectively.   we show that axioms can be integrated into a planner by using the asp to ip translation method used in the international planning competition (ipc ) formulation of @xcite, and that they lead to a smaller search space and shorter plan compared to the standard pddl formulation.
we study the application of a self - control mechanism proposed recently for a diluted network of binary patterns.   the model we look at is a fully - connected attractor neural network with neurons and patterns taking the values @xmath0 and pattern activity @x Math1.  in order to study the retrieval quality of the model, especially in the limit of low activity the mutual information content   is analysed. using evolution equations for the order parameters we find that the introduction of a time - dependent threshold leads to a significant improvement of the overlap, basin of attraction, critical capacity and information content of the network.. furthermore, the results of numerical simulations of a fully connected network of three - state neurons are compared with those of the models with a mean 50% activity.
the north - or - east - or-front ( nef ) model of supercooled liquids is a realization of the arrow model of ref.   @xcite, but with an externally imposed directional preference. in the nef model,   excitations carry an orientation which locally determines the directionality of the dynamics, making the system isotropic.we report numerical results for a wide range of dynamic observables in the nfe model, describing in detail distributions of the relevant timescales and lengthscales. by means of monte - carlo simulations, we also confirm some of the predictions for the arrows'arrow model, such as the three - dimensional fredrickson - andersen ( fa ) model, which describes strongly fragile materials. using experimental data from the glass transition regime close to the onset of super cooling, we compare our results to those obtained in the previous work.
the magellanic clouds contain a population of young rich star clusters, sometimes called populous clusters.   these clusters have been popular targets for studies of stellar evolution and cluster formation. with high - resolution spectroscopy ( hst ),   deep colour - magnitude diagrams can be produced, even of the dense central regions of the clusters. in this paper   we show that the age spread amongst the turn - off stars in the young clusters ngc1805 and ngc 1818 is much larger than the measured errors. to explain this age spread, we use a model of the initial mass function based on clump or protostar interactions. using this model, we find that the number of blue stragglers and be stars increases with the age of the cluster, and that the size of the age gap between the two clusters decreases with increasing metallicity.. the age gaps between the blue straggler stars and the be stars are also reduced by the presence of a circumstellar disk, which is thought to be responsible for the observed age spread.
the influence of the interchain coupling on the electronic properties of a half- and quarter - filled quasi-1d interacting electron system was studied theoretically.   it is predicted that with increasing interchain transfer integral such a system undergoes a deconfinement transition into a metallic state. in this paper   we study the effects of the temperature and energy scale at which the response of the system is probed on the electrochemical properties of ( tmttf)@xmath16 salts, which consist of weakly coupled molecular stacks along which the charge transport occurs. for a strictly 1d system where the interacting electrons are described by the luttinger liquid ( ll ) model,   the deconfinment transition at high enough temperature leads to a transition from a mott insulating to a ll conducting state, and finally to a dimensional crossover into an hdm state.
behind us is the standard model ( sm ), the theory of all known elementary particles and their interactions, and ahead of us is an equally remarkable array of possibilities for new phenomena at the weak scale.   never before has an energy scale been so widely anticipated to yield profound insights, and never before have there been so many ideas about exactly what these insights could be. in this article, we review the current state of experimental searches for supersymmetry, the most widely studied extension of the sm.
we investigate aspects of conformal invariance and quantum integrability of two dimensional ( 2d ) non linear sigma models ( nlsm ) on some symmetric supergroup manifolds.   we start from the principal chiral models ( pcm ) on the basic supergroups lie : @xmath3 and consider the following coset superspaces:@xmath4where @x math5. in all these cosets the factor algebra   is a maximal regular subalgebra of the basic lie superalgebras. for each of them we find that the model is conformal in all orders of perturbation theory, except for the first and the third cosets with wz term where the second coset is a product of identical simple group by itself. in the case of the fourth and the fifth cosets we find an atypical representation of the model in terms of a casimir like chiral algebra, which is consistent with the results obtained in the context of the ads / cft correspondence.
the 5.57  hr low - mass x - ray binary ( lmxrb )  is observed in the near - infrared ( asca ) region of the solar system.   the spectrum of  is complex and can not be easily fit by any of the standard models, but the observed lightcurve shows a partial eclipse and a smooth broad broad modulation with a minimum just prior to the eclipse. using a power - law continuum model, we show that the observed spectrum is best described by a k@xmath21/k@x Math17 ratio of @xmath17 at 0.5  kev and a fwhm fe - k line with a full - width half maximum of 4 kev. for the blackbody of ,   this ratio is 1:1.2 with a photon index of 1.3, a high - energy cutoff at 18  keV, and a broad fe-k line with an equivalent width of @Xmath1940  ev which is consistent with the observed emission features. however, there is evidence for an excess in the _ einstein _ solid state spectrometer spectrum which we can model as a thermal bremsstrahlung
we present a novel procedure for the classification of eclipsing binaries using only light curve parameters and an estimate of the binary s spectral type or color index.   the proposed procedure is based on the most comprehensive set of rules for the classification of systems with known classes contained in the old @xcite catalogue which, as our analysis has shown, is not accurate enough. to test the accuracy of the proposed method we tested it with the second version of the catalogue of eclipse variables ( cev )malkov / cev/, which contains about 7200 eclipsing binary systems with available evolutionary status data from the previous version of @xaicite. by comparing the results obtained from the experimental data with the results of the current study,   we show that the new procedure is more accurate than the old one, and can be used to quickly characterize large numbers of Eclipse binaries, even if the set of the observed parameters is incomplete.
the nonequilibrium work theorem, the one that relates fluctuations in the work performed by an unperturbed hamiltonian during a thermodynamic process in which a system is driven away from equilibrium to a free energy difference between two equilibrium states of the system, is well known.   however, the precise relationship between these two results has not been clarified in the literature, nor is it immediately obvious from a quick comparison of the original derivations. here  , we derive the two equalities within a single, ham Miltonian framework, and then illustrate them both using the simple model of a perturbed harmonic oscillator. for the special case of cyclic processes, in which the perturbation is turned on and then off,   the results show that the two predictions are equivalent.
a series of finite and infinite silicon nanotubes assembled by hydrogenated cage - like clusters was obtained using density functional theory ( dft ) calculations.   the structures were characterized by x - ray diffraction, transmission electron microscopy, and atomic force microscopy. a metal to half - metal transition was observed in fe - doped sints with the increasing of tube radius. additionally, the electronic and magnetic properties of sints can be accurately tuned by doping impurities at the center of the hollow tube.
abstractthe starburst phenomenon is a natural consequence of intense star formation and nuclear activity in many galaxies.   the presence of circumnuclear starbursts in an increasing number of local agns also suggests a connection between the starburst and the growth of central black holes at the centers of nearby galaxies. this possible starburst - agn connection dates back to the early universe and has direct bearings on our understanding of the evolution of the universe. since the triggering mechanism for agn activity probably depends on the luminosity of the agn, i make a distinction between the nearby, low - luminosity seyferts and fanaroff - riley type i ( fr i ) radio galaxies and the more distant and powerful quasars, fanar off - r Riley type ii ( fr ii ) radio galaxy, and ultraluminous infrared galaxies ( ulirgs ). in the last section of this paper,   i discuss recent results which appear to favor a starburst-agn connection in these two types of galaxies, and discuss the nature of this connection.
the cosmological distance ladder is a sequence of steps used by astronomers to derive distances within the solar system, throughout the galaxy, and beyond to the farthest galaxies detectable @xcite.   it hinges on simple geometry and the principles of surveying. in this paper   we determine the sizes of the first three rungs of the cosmologic distance ladder : 1 ) the radius of the earth ; 2 ) the distance to the moon ; and 3 ) the size of the astronomical unit, or au. with the hubble space telescope we can determine distances to other galaxies using the cepheid period - luminosity relation as far as 25 million parsecs @xmathite. since type ia supernovae are typically 4 billion times brighter than the sun at maximum brightness, they can be used to determine distances halfway across the observable universe with a 4-m class telescope.
we present a geodesic flow of a shallow layer of ideal, irrotational fluid on a curved substrate.   we show that the governing equation can be solved in terms of characteristics, which are geodesics on the two - dimensional curved substrate, possibly modified by gravity if it is present. using a non - orthogonal coordinate system to describe the substrate, we expand our fluid equations and derive a shallow - layer form. from this form, we find that the differential equations for advection and lyapunov are solvents for particle trajectories, and speculate on their chaotic nature.
pulsating white dwarf stars are the stellar remains of 9899% of stars in the sky.   most of them have atmospheres dominated by hydrogen ( das ; @xcite ), and are observed to pulsate in an instability strip located in the temperature range 1080012500k for @xmath0@xcite. here   we present a systematic study of the ensemble pulsation characteristics of all known non - interacting zz  ceti stars, using time - series photometry data from the sloan digital sky survey ( sdss ) and published pulsation spectra from the literature as well as private communication with our colleagues. over the course of this study, we obtain well - averaged values of weighted mean period and pulsation amplitudes which we present in this paper. among the 41 davs from the sdss,   the bg04 sample contains the largest number of pulsation periods and amplitudes ever reported for a significant sample of dav s.. the results show that the average pulsation amplitude is about 2.5 times larger than that of the b g04 sample, and that the mean period is about 1.6 times longer than the mean amplitude.
imperfect - information extensive - form games are often used to find a nash equilibrium, which is a profile of strategies in which no player can improve her outcome by unilaterally changing her strategy.   counterfactual regret minimization ( cfr ) is a popular iterative algorithm that minimizes regret independently at each decision point in the game. here   we introduce a new form of cfr, _ regret based pruning  ( rbp ), which greatly reduces the computation time needed to solve large imperfect - information games by temporarily pruning suboptimal actions.. specifically, if an action has negative regret, then rbp skips that action for the minimum number of iterations it would take for its regret to become positive in cfr. once pruning ends, all the data stored for the branch that is pruned can be discarded, and the space allocated to that branch can be freed. this is extremely advantageous when solving large imperfect-information games, which are often constrained by space and in which the set of best response actions may be orders of magnitude smaller than the size of the game ; for example, solving limit texas holdem required nearly 8 million core hours and a complex, domain - specific streaming compression
the deep core is a new telescope or better a counter event blurred at low energies ( below @xmath12 gev ) because muons are tracing tracks mostly projected along one string : the inner cone within @xcite may contain any neutrino arrival direction around the string axis azimuth angle.   we did use their prediction to calibrate the eventual cpt violation influence into their future rate@xcite. here   they review these predictions and now we reconsider our preliminary estimate, based on super kamiokande ones @xaite, estimates that partially disagree with the previous results @Xmab1, @xmab2 as well as @xmbi.
infrared ( ir ) spectroscopic studies of the dynamics of hydrogen bonds ( hbs ) continue to trigger considerable theoretical and experimental efforts.   the present study sets the focus on the ir spectrum of the normal species of phthalic acid monomethylester ( pmme ) in the range of the oh - stretching fundamental transition around 3000.a five - dimensional gas phase hamiltonian is determined and diagonalized to obtain detailed insight into the composition of vibrational eigenstates in the considered spectral range. a hybrid quantum mechanics / molecular mechanics ( qm / mm ) simulations of classical trajectories of pmme in ccl@xmath0 solution are performed. besides an analysis of the hb geometry in solution, the dipole - dipole autocorrelation function is calculated from which the ir absorption spectrum is obtained. for the condensed phase simulations,   two complementary models are considered : one based on the theory of the electronic ground state geometry of pm me in the gas phase and the other based on calculations of the quantum chemical behavior of the system in condensed phase. according to the first model, the ir lineshape in the od - stretching region is dominated by a fermi - resonance
gamma - ray ( gr ) astronomy is a powerful technique to study non - thermal phenomena in the universe, where cosmic ray ( cr ) particles are accelerated to extremely high energies.   it is now well established that grs can be used to investigate the origin of crs and to study the physics of the extragalactic background light. here   we review the history of gr astronomy and discuss the most recent developments in the field.
the factorization of the scattering cross section in @xmath4 annihilation has been a long - standing problem in qcd.   recently the advent of the soft - collinear effective theory ( scet ) facilitates the factorization proof in a straightforward way. here   we employ the generalized exclusive jet algorithm, which is defined as@xmath18 where the power of the energy in eq. (  ) is replaced by @x Math17.    we show that the generalizedexclusive jet algorithm is infrared safe for all cases of @x math4 annihilation.
the neutrino spectrum of a supernova is a powerful tool for studying the explosion physics of massive stars since it allows us to see down all the way to the core of the proto - neutron star.   the spectra of the next galactic supernova will provide us with the opportunity to test the core collapse paradigm by detecting the neutrinos from the next nearby supernova. in this article   we review the current understanding of the role of neutrines in the explosion of the supernova and discuss the effects of the mixing between neutrine flavors on the density profile of the exploding star.
the dynamical behavior of large populations of nonlinearly coupled oscillators may describe many phenomena in physics, biology and medicine.   the kuramoto model, @xcite, is well - known for its synchronization of mean - field coupled phase oscillators with different natural frequencies. to describe certain biological phenomena,   inertial effects should be added to this model. in this paper  , we study oscillator synchronization and transition from incoherence to synchronization in the model (  ) - (  ) where the natural frequency of an oscillator is a new independent variable, which is allowed to vary with time.we find that the left side of ( -(fpe )   is time independent. normalization to unity of the initial probability density then implies ( _ ) for the solution of (_ - ( norma)_.    the incoherent solution of these equations asigns equal probability to all angles and has @xmath25 ( or simply _ incoherence _ ) as the center of the equilibrium. by contrast, the synchronization solution of {1,2}-(
the bouncing ball model consists of a classical particle of mass @xmath0 which is confined to bounce between two infinitely heavy and rigid walls @xcite.   one of the walls is assumed to be fixed while the other one moves in time according to a periodic function. here  , we study a non dissipative version of this model seeking to understand and describe some of its dynamical properties considering however that the motion of the moving wall is given via a crank - connecting rod scheme. for such a scheme, it is known that there are two different kinds of dissipation : ( 1 ) a drag force and ( 2 ) a dissipation acting on the particle through inelastic hits of the particles with the moving walls. using a combination of the two kinds of damping forces, we show that the equilibrium energy gain of the particle is reduced by a factor of 0.5 when the particle suffers elastic collisions with the stationary wall. under the same conditions,   the particle experiences a restitution coefficient of about 0.1  kcal / mol and the phase space is of mixed kind, so that the particle undergoes a fractional loss of energy upon collisions with both the stationary and moving walls at the same time
the deconfined interacting quark  gluon plasma phase ( qgp ) is the equilibrium state of matter at high temperature and/or density.   it is believed that this state has been present in the early universe, 10 - 20@xmath2s into its evolution. to form qgp in the laboratory we perform relativistic heavy ion collisions in which a domain of ( space, time ) much larger than normal hadron size is formed, in which color - charged quarks and gluons are propagating constrained by external ` frozen vacuum ', which abhors color  @xcite. here   we present a numerical analysis of the effects of the size of the interaction region and the reaction energy on the yield of strange quarks in the source of the experimentally studied experimentally induced qgp.the results show that the yield per participant @xmath5 divided by a reference yield obtained in @x Math6 reactions is enhanced by about 0.1 cm2 over the range of @x math5 to ~0.2 cm2, which is in agreement with our studies of kinetic strangeness production and strangeness yield increasing with the number of participating baryons and reaction energy
the two - degree field galaxy redshift survey ( 2dfgrs : @xcite ) and the main galaxy sample@xcite of the sloan digital sky survey have provided detailed maps of the local structure from hundreds of thousands of galaxies of all types at a mean redshift of @xmath4.   the present paper describes a new survey which combines the precision of the sdss photometric survey with the spectroscopic capabilities of the 2df instrument on the 3.9 m anglo - australian telescope ( aat ), to extend the lrg survey from @x Math6 to @x math7. in total, 10,000 luminous red galaxies ( lrgs )   were selected for the survey, which will be used to investigate the evolution of the most massive elliptical galaxies in the local universe and the clustering of matter when the universe was about two thirds of its present age. by increasing the exposure time of the aat to 4h and targetting only the relatively rare lrg targets for spectroscopy in the red spectral region, 2df can reach @x maths13 and @x mathematics14, and the surface density of lrg targets requires only
the partially conserved axial vector current ( pcac ) relationship and corresponding current algebra results are in conformity with experimental data within a few percent.   this good agreement between theory and experiments is interpreted as due to an underlying approximate chiral @xmath2 symmetry, which is explicitly broken down by up and down current quark masses of a few mev much smaller than the hadronic mass scale of 1 gev. under the assumption that there is a diquark condensation inside a nucleon, we investigate in section 4 the necessity and the consequences of a modification of the pcac relation and related current algebra result. for that purpose  , we classify the spontaneous chiral symmetry belonging to the same chain, namely@xmath7, into categories characterized by their order parameters introduced in ref.    @xcite, which are generic in nature.the generality of the discussion allows the results to be applied to any model with a similar phase structure as the one obtained in ref : @xaite.  also, we explore possible extensions that are observable and are nevertheless consistent with our present knowledge.
in @xcite it is conjectured that the number @xmath6 of all numerical semigroups of genus@xmath2 behaves like the fibonacci numbers.   the goal of this paper is to provide results for better understanding the semigroup tree and give possible directions for attacking the previous conjecture. in the first section   we show that the bounds given in @xcitesite are a consequence of the fact that only two kinds of generators exist in a numerical semigroup larger than or equal to its conductor. in sections    we study the existence of weak and strong generators of numerical semiblockers in three well - known classes of numericalSemigroups : symmetric, pseudo - symmetryetric, and arf Semigroups. in each of these classes we find that primality and coprimality of integers appear in the scene as discriminating factors. in part   this is due to their role in determining the number of infinite chains in which the semi - symmetric semigroup lies. in parts   i and ii we give what we think should be future directions for attacked the conjecture on the Fibonacci - like
high - redshift quasars provide a powerful tool to study the early universe. in this paper   we introduce a new method for finding @xmath0 quaars by using regions with overlapping imaging in the sloan digital sky survey ( sdss ).   these overlap regions allow us to select quasARS that are fainter than those found in the sdss single - epoch images.    here we report eight new quasarts found in our first search of @x math110.5 mag fainters in the overlap regions, which are @x Math110.3 mag faintter than the quashers selected from sdssSingle-epidemiological data. among them, three are near the eddington limit and show broad emission lines indicating that vigorous star formation and element enrichment have occurred in their host galaxies.
muse is a giant integral field spectrograph that will be commissioned as a second generation vlt instrument starting in 2012.   the main goals of the muse data processing pipeline are to fully reduce all exposures into ready - to - use datacubes ( euro3d format or fits with naxis=3 ) without creating a backlog ( a requirement on scope of the reduction and the speed ), to track bad pixels, propagate error information, and to minimize the rebinning steps. especially the last two goals are connected and not yet commonly implemented in existing data reduction systems. here   we discuss the details of the process of reducing the raw data from the vlt muse data using a one - step resampling approach.    the method is based on a " pixel table " which contains all illuminated pixels ( the data value, the bad pixel status, and the variance ) of one exposure together with the coordinates ( @xmath4,@xmath5, and @x math6 ).. the data are then transfered into such a pixel table and each transformation that would classically require an interpolation step is carried out just by changing the coordinates of each table entry. for each transformation,
we study the current - induced atomic dynamics in a partially dehydrogenated armchair graphene ribbon using a semi - classical langevin approach.   we show that the atomic motion of the dehydrogenated carbon dimer at the nanoribbon boundaries is relatively decoupled from other atoms and also the rest of the carbon atoms, and this results in several nearly degenerate atomic vibrations, where each of these involves mainly one dimer. however, a coupling of the dimer vibrations takes place via the flowing electrical current. by combining theoretical and numerical methods, we find that the vibrational modes of the hydrogenated atom at the armchair edge of the ribbon are mostly coupled to each other via the current carrying electronic states, and have little damping due to the coupling to the phonon reservoir.
the carina dwarf spheroidal ( dsph ) galaxy was the first to be observed in the early days of modern ccd detectors and remains one of the more spectacular examples of a dsphy galaxy with a significant intermediate - age population.   many main - sequence stars are found in carina within the instability strip where short - period pulsating stars known as dwarf cepheids, sx  phe stars, @xmath7  sct stars, or ultra - short - time cep heids are found. in this paper   we describe a search for these stars using time - series photometric observations of the main sequence turnoffs of the carina star system. during two runs in 1989 and 1990  , we have discovered 20 dwarf cephalogues in the region where they are most commonly found. among them, we find that the majority are red - stragglers from their parent clusters, which are located above and to the blue of the major sequence turnoff. because of their modest luminosities, they are expected to have magnitudes of @x math022 - 24 in carinala, rather faint for such short individual exposures. however, because they have
the main result of this paper is of a style intermediating between two ends, stating that two smooth projective varieties related by a  semismall flop _ ( ) have isomorphic chow motives with coefficients in a local ring.   the main reason for this is that the singular cohomology groups of a smooth variety @xmath2 of a birational smooth model are unchanged under semism all flops.
in the quantum world it is relatively easy to compare ( quantitatively, or qualitatively ) features of physical systems and to conclude with certainty whether the systems possess the same properties, or not. on the other hand, the statistical nature of the quantum theory restricts our ability to provide deterministic conclusions / predictions even in the simplest experimental situations.   the aim of the present paper is to find the optimal unambiguous state comparison procedure in the case we have more copies of the two quantum states which we want to compare. in the paper we derive the optimal multi - copy comparator for general pure states and coherent states. in both cases   we investigate the behavior of the success probability as a function of the number of copies @xmath10 and@xmath11 of the second unknown state of the compared states. moreover, we propose a relatively simple experimental setup realizing the comparison of coherent states by measuring the complex amplitudes of the first and second states.
microlensing observations of the bulge and the magellanic cloud have been conducted in baade s window and toward the lmc and smc.   the results of these observations indicate that the majority of the lenses detected to date are binary - lens events, that blending is ubiquitous, and that a significant portion of the optical depth measured for both stars is actually higher than predicted.
the mass spectrum of quarks is characterized by a large hierarchy between quark masses from different families, @xmath3, and the isospin violation is also hierarchical : it is very strong in the third family, strong ( although essentially weaker ) in the second family, and mild in the first one.   the origin of these features is still mysterious : in the standard model ( sm ), it is required to introduce hierarchical yukawa couplings by hand. in this paper  , we will introduce a new class of models describing the quark mass hierarchy that are independent of the electroweak symmetry breaking ( ewsb ) interactions.    we assume that the dynamics primarily responsible for the ewbs leads to the generation of the observed ratio@xmath16 in the 2nd family, i.e., the top quark is the main source of the strong top - quark interactions. on the other hand, because these interactions are subcritical, they play a minor role in the formation of the composite higgs bosons ( resonances ) composed of the quarks and antiquarks of the 3rd family. at last, we propose a dynamical higgs mechanism with a higgs doublet
the population of galaxies with stellar masses greater than 10@xmath2 m@x Math5 is dominated by large early  type galaxies with correspondingly large sizes.   however, it has remained unknown whether the stars in these galaxies were all assembled in the same system, or formed in lower mass galaxies that later merged. here  , we explore the evolution of the stellar mass - size relation of these systems at a given stellar mass using a new model of galaxy formation based on the hierarchical merging scenario.    we find that the magnitude of the relationship between star mass and galaxy size increases with cosmic time, with the largest increase in size observed at higher redshifts. to test this model, we use a number density analysis to estimate the number of galaxies that would have been formed by merging in the early universe. for each galaxy merger,   we find a significant increase in the size of the star - to - galaxy ratio ( sbr ), which is a function of galaxy mass, and a significant decrease in the value of the sbr for the first galaxy merger after each merger. as cosmic time evolves, the mean sbr decreases from 1.0 to 0.9 times faster than the expected rate of galaxy
the most natural extension of general relativity with higher curvature terms and with the assumption of einstein  that the left hand side of the field equations is the most general symmetric conserved tensor containing no more than two - derivatives of the metric  is lovelock theory.   the problem with the total action of e Einstein gravity is that it is divergent when evaluated on the solutions of anti - de sitter / conformal field theory ( ads / cft ) solutions of its dual theory. for asymptotically ads solutions of this dual theory,   one may remove the non - logarithmic divergences in the action by adding a counterterm action which is a functional of the boundary curvature invariants. here  , we present a new method for the calculation of the action and conserved quantities intrinsically without reliance on any reference spacetime using the counterterm of lovelocock gravity with curved horizon.
weak - coupling renormalization group ( rg ) predictions of superconducting instability in @xmath0 are compared to experimental results based on density functional theory ( dft ) calculations and angle - resolved photoemission spectroscopy ( arpes ) data.   we find that the perturbative rg results can be very sensitive to details in the input band structures, which would imply that extra attention is necessary in attempts to connect rg predictions with experiments. here  , we investigate this issue in the context of strain - dependence of superconduction instability in@xmath1@xcite using a three - band hubbard model for the uniaxially strained @x math0 as an example to contrast the rg results obtained from a dft calculation and those obtained from extrapolating the arpes data in the absence of strain. by comparing the two sets of results to the experimentally measured strain - dependent @x maths1@xaite, we show that the magnitude of the band - selective mass renormalizations found in the ruthenate films of biaxial strain- and epitaxial strain - correlated materials can affect the strength of the rg prediction for dominant pairing channel in a qualitative
the iras satellite has opened the mid- to far - ir sky, and has revealed that the bolometric luminosities of many galaxies are dominated by this spectral region.   this has raised questions concerning the evolution of galaxies in this region, the role of dust - extinction in the formation of galaxies, the relationship between quasars and galaxies, and the nature of galaxy formation itself. here   we review the results of the recent work using data from the iso space observatory ( iso ) instrument, which allows us to reach flux limits @xmath4100 times fainter than those achieved by iras while observing fairly large areas (@xmath40.1 sq. degree in integration times of 1.0 to 2.0 s ) in the mid - ir at wavelengths ranging from 12 to 25 and 60 to 100 jy. for the majority of the objects studied,   the observed fluxes are not much smaller than 1jy, and it is possible to detect galaxies out to z=0.2 with sensitivities of @x math40.3 jy in the medium - ir bands.    these observations have implications for our understanding of the history of galaxy evolution, as well
the position of the frontier molecular orbitals of the organic light harvesting material @xcite with respect to the electrode bands is a key design quantity for engineering materials combinations with enhanced light - to - current conversion.   it is therefore of great importance to have at hand computational tools capable of accurate predictions of levels alignment at the metal / molecule interface. in this paper   we present a new approach to this problem using many - body perturbation theory ( gw ) and density functional theory ( dft ), which includes non - local correlation effects in the description of the excitation spectrum of a molecule adsorbed on a metallic surface. as a consequence   the gw approach is able to predict with satisfactory accuracy the levels alignment of the molecule in the gas phase, whereas the dft kohn - sham approach fails to do so. by combining the two approaches we show that the homo - lumo gap becomes more prominent as the molecule gets closer to the surface, where the ionization potentials of the molecules are reduced by about 1.5 kcal / mol due to the coulomb interaction between the added charge on the molecule and the screening electrons in the substrate.
we study a type of resampling procedure for markov chains, called weighted ensemble ( we ) sampling.   we show that we sampling is unbiased even when the bins and the number of replicas per bin are chosen adaptively. to speed up the calculation of reaction rates and probabilities, we use a preconditioning step in which a markov state model ( msm ) is used to approximate the stationary distribution of a nonreversible process. from this information,   it is possible to optimize the we sampling in this relaxation step, in the sense that the variance in the appropriate stationary calculation is minimized. using this strategy, we show in a simple model that this adaptive sampling can be significantly better than traditional we sampling.
the higgs sector of the standard model is studied in this paper.   we derive the exact spectrum of the theory using the feynman - kac formula for the quartic coupling of the gauge fields to the higgs field and the yukawa couplings of the fermion fields. as a by - product of this theorem  , we provide a mathematical technique to solve partial differential equations like that for the green function using lorentz invariance and fourier transform. from this one   it is shown that the spectrum is a superimposed one on the mass of the higgens particle and appears like substructures are at work.. this could be explained by a higher level theory as string theory or technicolor.
the moving mesh method is a widely used method for simulating solutions of nonlinear partial differential equations that exhibit solutions having some type of singularity, such as self - similar blow - up problems.   the moving mesh pde ( or mmpde ) approach is derived to evolve the mesh points in such a way that they tend towards an equidistributed mesh at steady state, in the sense that the meshes are positioned in space so as to equally distribute some measure of the solution error. in previous results reported in the literature, the mesh relaxation time, usually denoted as @xmath0, is invariably taken to be a constant for any given simulation ; however, the main purpose of this paper is to consider situations where taking constant @x Math0 may not be appropriate. keeping in mind that @x math0 can be interpreted as a time scale for the mesh motion, we present an approach for adaptively selecting a time - dependent mesh smoothing parameter, which is optimal in an appropriate sense, and demonstrate its application in the case of a set of Blow - Up problems.
the scale - free scaling laws of the hot gas in clusters of galaxies seem to be very important for understanding the physics of galaxy formation.   we have recently re - evaluated the perturbation amplitude implied by cluster observations using a variety of techniques that circumvent the standard mass - temperature relation, generally implying a much lower power - spectrum amplitude than the one implied by the standard relation. here  , we review the results of these studies and discuss how they are related to the present - day properties of clusters.
the center vortices model @xcite introduced in the late 1970 s by t hooft is one of the most widely used models to explain quark confinement.   faber, greensite and olejnk ( su(3 ) ) explicitly worked out the model for su(2 ) and gave results for a particular flux distribution within the vortice. here  , i study the existence of casimir scaling at intermediate distances and the pattern of screening at large distances from the center of the vortex using the fat - center - vourices model. as expected, the model shows that the potentials of higher representation static quarks are more convex than those of lower representation quarks at intermediate distance. however, when the model is extended to large transverse distances, it does not agree with the results obtained by numerical simulations.
we discuss the scenario of light neutralino dark matter ( dm ) in the minimal supersymmetric standard model ( mssm ).   we show that the results of the dama / libra and cogent collaborations, which suggest a light dm field with a relatively large scattering cross - section with nucleons, come into disfavour with the latest lhc bounds, especially constraints from the neutral higgs boson search.
we examine the effect of strong gravitational lensing ( sl ) on the einstein radius of a large number of massive galaxy clusters by fitting model profiles fitted to weak - lensing measurements of the same clusters.   we find that the mass of the sunyaev - zeldovich ( sz ) effect - modelled inner mass profile is well - constrained by the number of initially known multiply - lensed systems in the cluster, and that the size of the sz effect is not significantly different between the measured and predicted mass maps for the same cluster. however, there is a significant inconsistency between the observed einstein radii directly measured from sl analyses and those predicted from models fitted to data obtained from weak lensing experiments of similar clusters, often due to background selection and dilution problems over a wide radial range. as a result,   the results of this study are compared with theoretical predictions of the best - fit model profiles for a sample of 1.5 billion galaxy clusters.
we develop an appropriate non - equilibrium thermodynamics for the study of glassy relaxation.   we use the second law of thermodynamics, which is applicable to all systems including glasses, to describe the relaxation of a glass from its equilibrium state to a non - equilibriated state. in particular, we focus on the effects of the temperature and the viscosity of the surrounding medium on the relaxation properties of the glass. using this framework, we show that the relaxation time of the system depends not only upon the temperature of the medium, but also on the inhomogeneity of the liquidlike properties such as its enthalpy, volume, and volume / volume ratio. by taking into account the fact that the system under study is considered to be a model system, we find that the laws of relaxation are independent of the structural or otherwise of the processes going inside the system and do not require any sophisticated concepts like ergodicity or its loss.
@xcite carbon nanotubes are excellent systems to hold inside nearly perfect one - dimensional fluids.   the quasi - one dimensionality of these carbon tubes is itself an interesting property from a purely theoretical point of view. in the present work,   diffusion monte carlo ( dmc ) calculations are carried out to study the influence of both the interparticle potential and mass on the thermodynamic behavior of the isotopes of molecular hydrogen, especially h@xmath0 and d@x Math0, adsorbed inside a carbon nantube. since the electronic structure of molecular deuterium and hydrogen is the same, the d@Xmath0-d@x maths0 interatomic potential is identical to that of the h@ x math0-h@x math0 one. moreover, the mass of the d @xMath0 molecule is very similar to that for a @xmath1he atom. by comparing the results of the experiments with those of the simulations of the experimentally observed interactions between the two isotopes  , we show that the experimental results are not only consistent with the theoretical ones, but also support the existence of a liquid phase at zero temperature in both 2d and
ultra - wideband ( uwb ) systems have received special research interest as a promising technology for high - speed, high - precision, strong penetration short - range wireless communication applications with the ability to overlay existing narrowband systems @xcite. in this paper  , we introduce a novel scheme for uwb applications, named as self reference uwb ( sr ), which uses as reference signal the absolute value of a replica of a transmitted data signal multiplied by the gaussian monocycle waveform.   compared to the conventional transmitted reference ( tr ) scheme, sr constructs the reference pulse from the transmitted data symbol, resulting in double data rates ( as in differential tr scheme ) and in lower complexity. moreover, the sr scheme is able to take advantage of the multipath diversity of multipath components ( mpcs ) that make uwb a viable candidate for communications in harsh reference scenarios, such as industrial / factory indoor and forest / sub - urban outdoor environments.
we use mid - infrared ( mid - ir ) observations of the subaru/_xmm - newton _ deep field to search for evidence of nuclear accretion in a manner that is far less dependent on orientation.   we find that at low redshift, the most massive super - massive black holes ( smbh ) typically have very low accretion rates with systematically higher average values at @xmath4 2, the so - called'quasar epoch'( @xcite ). these observational results fit in with theoretical ideas that a ` quasar mode'of feedback is prevalent in the distant universe, and that a'radio mode'feedback is dominant at lower redshift ( e.g. @xcites ).
high - energy heavy - ion collisions can produce a hot, dense, and deconfined nuclear medium, dubbed the quark - gluon plasma ( qgp ).   chiral domains may be created locally in the qgp through various mechanisms on an event - by - event basis ( e.g. topological fluctuations in the gluonic sector or glasma flux tubes ). in a noncentral collision, a strong magnetic field ( @xmath3  t ) can be produced ( mostly by energetic spectator protons )  , and will induce an electric current along@xmath4 in chiral regions, which is called the chiral magnetic effect ( cme ). here   we review the experimental results in the past decade to show that the cme is not the only transport phenomenon that occurs in the presence of a chirally symmetric phase. for a given vorticity,   the c me induces a vector current along @x Math4 in a chiral medium, and this is reflected in the measurement of charge - dependent elliptic flow.
unveiling the nature of the unidentified gamma - ray sources ( ugss ) is one of the biggest challenges in contemporary gamma -ray astronomy.   many @xmath1-ray objects have not been conclusively associated with their low energy counterparts at other frequencies @xcite, although various classes have been investigated to understand whether they are likely to be detected at these energies or not. according to the second _ fermi _  large area telescope ( lat ) catalog ( 2fgl ; *????   * ), @x Math01/3 of the unassociated sources are blazars, the rarest class of radio loud active galactic nuclei, because their emission dominates the @x math 1-ray sky. in the present paper   we develop a new association method to identify the blazar - like counterpart of an ugs based on the results of a preliminary analysis of the wide - field infrared survey explorer ( _ wise _ ) color - color data from the --@xmath3 m color - space. using this method  , we successfully test the association procedure on all the blazrs listed in the
spin squeezing, or pseudo spin squeezing, is a property of quantum entanglement that can occur in many models with a variety of atom - atom interactions.   we are interested in the possibility and the condition for spin squeezing in the pseudo - spin of coupled ground states in an optical lattice model with spin-1 bosons. within this work, we present a mean - field approximation of the bose - hubbard hamiltonian model of a system of neutral bosonic atoms with hyperfine spin @xmath3 in an octahedral optical lattices.    the model system is characterized by a quantum phase transition between two distinct phases : a superfluid and a mott - insulator.. the experimental phase transition is achieved by coupling the standing wave laser fields of the lattice to atomic electronic transitions, which are dipole coupled to electron excited states. as a result of the off - resonant coupling,   the electronic modes of the systems are coupled to the ground states of the spin-@xmath0 squeezed spin state, and the quenched spin state is a correlated state consisting of both the electronic mode and the quasi - spin state of the sp2 boson. using the
the design of a new super - flavor factory ( super - b ) for the @xmath0 collider is presented.   the concept of combining linear and circular collider ideas to make a linear - circular b - factory was discussed in the late 1980 s, although only circular b-farms were built in the 1990s.. recent advances in b - factories performance and solid linear collider design progress has reopened this design avenue. 	 the design presented here combines extensions of the design of the present 10@xmath1 @x Math2s@x maths3 @x math0 colliders and linear collidors to allow improved beam parameters to be achieved.    the results show that the proposed design can be successfully applied to the construction and operation of a future super - flavors factory.
ldpc codes are very useful for iterative decoding of binary information.   the main reason for this success is that they perform very close to the theoretical shannon limit. in this article  , we introduce new incidence structures obtained from the incidence relations between points and strict transforms of conics on the affine plane blown  up at all of its rational points. using these incidence structures, we construct * binary * ldpc codes and study their parameters. a formula giving their minimum distance is proved and their dimension is discussed. using the computer algebra software magma,   two conjectures are stated on the dimensions of some of these codes and the actual dimension of some code types is computed. by simulating these codes on the gaussian channel, some of them turn out to be better than regular gallager codes having the same rates and row weight.
the automatic extraction of acronyms and their meaning from corpora is an important sub - task of text mining.   much work has been done on it, but there is no consensus on the best way to do it. here   we show how the alignment - based approach to acronym - meaning extraction can be implemented by means of a 3-tape weighted finite - state machine ( 3-wfsm ). using a regular expression that defines the task in as much detail as we wish,   the 3- wfsm can be automatically generated from a clear and relatively simple regular expression. for example, we extract from a corpus all sentences that contain acronym in brackets, such as    between a hidden markov model ( hmm ) and a weighted infinite - state automaton ( wfsa ), and normalize these pairs : capital letters are transformed into small ones, and separators into underscores. then, we split these pairs into pairs consisting of an acronym and the text chunk that precedes it ( starting from the sentence beginning or form the preceding acronym ).. we use a superscript@xmath11 to indicate the arity of a @xmath12
we present a monte - carlo event generator for the study of the quark gluon plasma ( qgp ) in heavy - ion collisions.   the event generator is based on the higher - twist scheme and includes a consistent space - time structure with fluctuations within the simulation. to test the suitability of this model, we have used it to study the effects of a thermal medium on the jet modification process in a series of relativistic heavy -ion collisions. from the generated event,   two partons at midrapidity ( @xmath2 ) were taken for jet quenching and the high transverse momentum (@xmath1 ) partons were used for the falling jet spectrum. using the experimentally observed data as a reference, we show that the effect of the medium on jet modification is similar to that of the experimental data.
the icecube experiment at the south pole has recently discovered a large number of high energy neutrino events with deposited energies greater than 30  tev.   we discuss the spectrum and flavor composition of these events in terms of the spectral shape of the observed flux, which is consistent with the uhecr paradigm that the neutrinos are produced by interactions between nuclei and matter. while the source population of the ultra - high energy cosmic rays ( uhec ) is cosmologically distributed such that it roughly follows the star formation rate, there is no evidence for directional clusters or time - wise clustering of events. instead, we postulate that the observed events are due to interactions between protons and photons, which are accelerated to higher energies within the sources. as a consequence,   the secondaries are decoupled from the firstaries by magnetic field effects on the secondary muons and pions, which can significantly alter the spectra of the interacting nuclei. here  , we take into account the composition of the nuclei in the sources and discuss if the cutoff at pev neutrine energies can be consistent with this paradigm if heavier nuclei are accelerated up to higher temperatures within the
the high temperature ( ht ) and low temperature ( lt ) phases of the prussian blue analogues @xcite, a(i)m(ii, where a=na, k, rb, cs ; m=mn, co, cr ; n= ( fe, cr ) ; are characterized by esr spectroscopy.   the ht phase is cubic with mn@x Math3 and fe@x math5 ions in s=5/2 and s=1/2 spin states respectively. at all temperatures between 4  k and 320  k a single strong esr line is observed at both 9.4 and 222.4 ghz in powder pba samples. in single crystals,   defects with lower symmetry are also observed but no esr of the bulk can be found. to understand the origin of the esr active defects, we set a lower limit for the unusually fast spin relaxation rate in the bulk.
cosmic strings are a line - like version of topological defects in the universe that are predicted in the framework of fundamental string theory.   the existence of cosmic strings is a central question in cosmology today, and experimental constraints have been obtained on a possible string contribution in terms of upper bounds on the string tension @xmath5. here   we present a new method for mapping the string network potentially imprinted in the cosmic microwave background temperature data from the wilkinson microwave anisotropy probe (@xmath4 ) satellite experiment using a bayesian approach based on statistical models for both the string signal and the noise. by applying the theory of compressed sensing to the reconstruction of a string signal from radio - interferometric observations of small patches of the celestial sphere at the same arcminute resolution  , we show that the map of the string networks can be solved by the magnitude of the gradient of the band - limited signal, which is very sparse or compressible in nature, with significant amplitudes only along the strings themselves. under the most standard assumptions, radio interferometers provide a noisy and incomplete fourier coverage of the planar signal. instead, the reconstruction amounts to solving an ill - posed inverse problem
photoinjector is one of the key components to provide high brightness electron beam for next generation light sources.   the lifetime of the photoinjected photocathode depends on the lifetime and the quantum efficiency of the photocathodes. in this paper  , we propose a new type of photoemissive material that is masked from the accelerating vacuum chamber by using a mask electrode with a small opening hole at the front of the photoluminescence source. when the photo emissive surface is exposed to the back bombardment of ionized ions and multipacting electrons, the electrochemical energy of the laser beam can be reduced by removing the dark current and the secondary electron emission from the photocathsode surface. also, the photo electron beam density distribution can be more uniform by using the opening hole as a transverse cut - off to the gaussian laser beam which reduces the growth of the beam emittance from the nonlinear space - charge effects. through beam dynamics simulations, we study the effects of the masked photocathodomain on the beam quality through an electron beam dynamics simulation inside a masked photocathyode gun.
the behaviour of individual fast charged particles in magnetic turbulence is relevant to a number of problems in plasma astrophysics, from the solar wind to interstellar medium and cosmic rays at highest energy.   however, in contrast to cosmic rays with energies beyond the gev scale, a thorough understanding of the particle transport properties can be attained only in interplanetary space, where _ in situ _ measurements of both magnetic turbulence energy spectrum and particles energy are possible. here  , we explore the transition to the diffusion regime in a magnetostatic turbulence by using the first - order orbit theory as proposed by @xcite. based on two assumptions : 1 ) the particle gyroradius is much smaller than any variation length scale of magnetic field and 2 ) the turbulent magnetic energy is much larger than the average magnetic field energy, we disentangle the cross - field particle motion into two separate components : field lines meandering and gradient / curvature drift from the local field line.. the field - line meandering has been found to be the transverse gyroperiod - averaged motion of the guiding center away from theLocal field line ( ~1.5    0.2   for the case of jovian
reduced - rank adaptive filters are cost - effective techniques when dealing with problems involving large filters and reduced training.   the computational complexity required by combination schemes is due to the use of two or more adaptive filters in parallel and can become unacceptably high with large filters. in this paper, we propose schemes for joint model - order and step - size adaptation of reduced - rankadaptive filters based on the joint iterative interpolation, decimation, and filtering ( jidf ) technique @xcite which address these drawbacks of thejidf scheme. using convex combination strategies,   we derive least - mean squares ( lms ) reduced - Rank adaptive filters that are optimized in parallel operating with different model orders and step sizes. as a first step, we derive a tree structure where only two parallel structures are combined at each stage. here, we present the derivation of the convex combiners and discuss the simulation results.
the existence of the hollow configuration of an atomic nucleus is still in debate.   it is thus necessary to re - study whether the hollow atomic nucleus exists or not by completely different theoretical methods. based on the isospin - dependent boltzmann nuclear transport model, here   i show that atomic nuclei with super - large mass number or with excitation energy may both are hollow. besides practical applications, the existence of hollow nuclear matter may have many implications in quantum many - body theory, nuclear physics, atomic physics and the configuration of neutron stars, etc.
cygnus a ( @xmath2 ) is the best studied example and prototype of a powerful fr ii radio galaxy and is also one of the brightest nearby x - ray sources.   imaging from the wiyn 3.5 m telescope in 1998a showed that cygnu a is located in a rich, high velocity dispersion cluster of hot gas with a mass inflow rate as high as @x Math4 mpc in extent near the center of the cluster. using new imaging and spectroscopic data from the kpno 0.9 m 22 field centered on cy gnus a from @xcite, we present a detailed substructure analysis of this cluster and compare the results to a cluster merger model based on the x -ray gas temperature structure.    the results show that the cluster is a complex cluster of two similar mass subclusters with a strong cooling - flow but not a strong heating - flow ; the latter could be explained by a simple model involving the merger of two similarly sized clusters colliding head - on and developing a shock between them.
compact @xmath0 gauge theory in ( 2 + 1 ) dimensions is one of the simplest models with dynamical gauge degrees of freedom and possesses some important similarities with qcd @xcite.   the model has been shown to confine electrically charged particles even in the weak - coupling regime ( at zero temperature )@xcite, for the confinement is understood as a result of the dynamics of the monopoles which emerge due to the compactness of the gauge field. in the present paper   we investigate the influence of tadpole improvement on isotropic and anisotropic lattices for the @x math0 model in ( two - dimensional ) dimensions in order to determine the renormalization of the bare anisotropy at weak and strong couplings using both standard and tadpole improved wilson gauge action in sect.ii and sect.v.we also apply tadpole improvements to calculations of the static quark potential, the string tension and the scalar glueball masses and compare the results with simulations of the wilson action.
the study of large graphs and networks has become an important topic in applied mathematics, computer sciences and beyond.   the role played by such large graphs in representing the structural skeleton of complex systems has triggered the production of many indices that try to quantify the different structural characteristics of these networks. among those mathematical approaches used nowadays for studying networks, matrix functions @xcite of adjacency matrices of graphs have received an increasing visibility due to their involvement in the so - called  communicability functions _  . these functions characterize how much information flows between two different nodes of a graph by accounting for a weighted sum of all the routes connecting them. here   we consider the use of a double - factorial penalization 1/@xmath12 of walks as a way to increase the contribution of longer walks in Communicability - based functions for graphs and real - world networks. using coefficients @xmath4 that do not penalize the longer walks as heavily as the inverse factorial scaling will reveal some structural information of networks which is important in practical applications of these indices.
word segmentation problem is one of the most important problems in statistical linguistics.   it is to find ways to distinguish the correct segmentation from the wrong segmentation, in the sense that adjacent letters in the original text keep adjacent while letters separated by spaces and/or punctuation marks in the originally text are separated by space in the segmentation. here  , we present a new method for word segmentation which is based on the concept of segmentation entropy. as a proof of the proposed method,   we consider a problem under constraints, so that one important concept  segmentation entropism  can be introduced. using the maximum likelihood approach, we obtain a probability function which reaches its maximum on the right segmentation ( e.g., the number of words in each segmentation ). by maximizing the likelihood function   subjected to eq.(4 ) we obtain the entropy of the correct section of the original sequence. with the help of the entropy function, we show that the best way to discriminate the correct segments is to take into account the interword delimiters among the segmentations.
the design of frequency - selective pulses for magnetic resonance applications is a challenging task.   the space of possible pulse shapes is often reduced by forcing the solution to be a member of a particular family of functional forms ( for example, finite fourier series ) and, potentially, there are important solutions that are missed. in the present work, we show that optimal control theory can be used to design broadband and selective pulses that are simultaneously tolerant to rf inhomogeneity and relaxation effects. using this approach, we develop a new method for designing broadband and selectively selective pulses with respect to the phase dispersion in the phase of the final magnetization @xcite, which is more sensitive to relaxation effects than the standard efficient shinnar - leroux ( slr ) algorithm. as a result, we find that the choice of parameters for the selective pulse can be much more constrained compared to those for the broadband pulse, and that the optimal control methodology can be applied to the design of selective pulses which are tolerant to both relaxation effects and inhomogeneous rf conditions.
the growth of crystal phases from the melt occurs in many material processing applications such as zone refinement and epitaxial growth.   a classical theory by wilson for the growth of crystals rate from viscous melt is proposed based on the picture of abrupt interface separating semi - infinite melt and crystal@xcite. in this paper  , we derive interfacial kinetics using ginzburg - landau ( gl ) theory from a different yet more compact perspective. to understand the kinetics of the non - equilibrium solid - liquid interfaces of a given undercooling,   we explicitly computed the kinetic coefficients using the equilibrium density wave profiles, which is contrasted with that obtained through the approximation scheme proposed previously@xcite. finally, comparisons to molecular dynamics(md ) simulation and the physical origin of kinetic anisotropy are discussed.
the cavity method of statistical physics based on the bethe approximation provides efficient message - passing algorithms that have proven useful in the study of random constraint satisfaction and optimization problems. in this work   we propose an approximate expression for the matrix elements of the density matrix in terms of a locally consistent set of reduced density matrices.   the structure ( interaction graph ) of the trial density matrix is chosen such that for tree interaction graphs, the locally consistentSet of reduced densities we started from is globally consistent. then we use the above density matrix to write down the quantum transverse ising model free energy as a function of the reduced density Matrices and the cavity messages that are needed to compute the entropy within the bet he approximation. approximating these cavity messages with a product distribution ( or mean - field approximation ) leads to the classical bethe expression for enthalpy, which is expected to work well at high temperatures away from quantum phase transition points. by considering the two - spin marginals of the cavities  , we improve on this approximation by obtaining an approximate bethe entropy that depends only on the diagonals of the local reduced densityMatrices.
we use a growth or epidemic analysis to obtain new, high - precision values for the percolation thresholds of the simple cubic ( s.c. ), face - centered cubic ( f.c.c  . ) and body - centered square ( b.c.'s ) lattices using a monte - carlo simulation method.   we find that the most accurate values for each of the three - dimensional lattices are @xmath25 ( 2,097,152 ) wetted sites for the s. c.    lattice and@xmath26 ( 1,048,576 ) wetting sites for those lattices. from these values, we estimate the critical exponents and coefficients that enter into the finite - size and scaling functions of the two - dimensional systems.  in addition, we find some new estimates for the critical threshold values for bond percolations on the face - center cubic lattice @xcite.
tidal streams are long, filamentary structures that are the remnants of satellites tidally disrupted by the milky way.   they form a coherent phase - space structure in angle - action space, and can be used to infer properties of the galactic potential. here   we present a probabilistic model for tidal streams that is able to extract the parameters of a simple two - parameter potential from mock stream observations, and use these parameters to infer the posterior distribution of the galaxy's potential. given a set of observations, @xmath6, of stars believed to be members of a stream, we have a 6d set of galactic coordinates with associated errors described by the covariance matrix @x math10. using this formalism, we obtain the posterior distributions of the potentials of the stars in the stream, and compare them with those of the observed data. as a result  , we find that the results are consistent with the predictions of the bayes   s theorem, and that the proposed method is robust enough to handle large errors, missing data, and contaminants.
the origin of the young stars that lie in the galactic center ( gc ) is puzzling.   some of these stars lie in a near - keplerian disk, called clockwise ( cw ) disk, which is thought to be warped or tilted, since the orientation of its normal axis changes by @xmath5 from the inner edge to the outer edge. however, recent results from @xcite show that the cw disk extends only up to@xmath6 and it is neither significantly warped nor tilted. here  , we investigate the precession effects induced by dense gaseous rings on the cW disk by simulating the disruption of a turbulence - supported molecular cloud using the amuse software environment thanks to the direct - summation n - body code coupled with a smoothed particle hydrodynamics ( sph ) code. for each ring, we obtain self - consistently self - consistent rings that match the main properties of the circumnuclear ring ( cnr ), a ring of molecular gas that orbits the supermassive black hole ( smbh ) at the center of our galaxy, and we also account for the presence of warm gas in the inner cavity. as a result, we show
direct liquid injection chemical vapor deposition ( dli - cvd ) has been used to fabricate epitaxial thick cofe@xmath0o@x Math1 ( cfo ) films with near - perfect microstructure and excellent magnetic properties close to bulk cfo.   the results of our growth studies and the structural and magnetic properties of high - quality thick cfo films ( @xmath11 ) epitaxially grown on ( 100)-oriented mgal@x math0o=xmath1 ( mao ) substrates by dli-cvd method show that the optimal growth temperature window is found for the growth of high quality cfo thin film at a temperature of ~50 k. the optimum deposition parameters are found to be ~20c, ~30c, and ~40c for the formation of anhydrous co(acac)@x maths0o<xmath8 ( acac ) in the molar ratio of 1:2, which is sufficient to form a clear homogeneous structure with a diameter of ~10 nm and a height of ~5 nm.    the optimized deposition parameters have been found to also be suitable for the development of thick c fo films on
the hole - doped resonating valence bonds ( rvb ) state is a new class of variational states, in which spin and charge correlations are parameterized independently, without explicit spin nor gauge symmetry breaking.   such parameterization allows states with magnetic and independently d or s - wave superconducting ( off - diagonal ) order or disorder, thus permitting an unbiased determination of ground state spin and Charge correlations appropriate for the cuprates. using monte carlo and mean field calculations,   a phenomenological low energy effective hamiltonian is proposed, with two major components : heisenberg interaction for spins, and single or cooper pair hopping kinetic energy for fermion holes. regarding this model our key results are:(i ) for the magnetic energy alone, the local magnetization @xmath0 is _ weakly dependent _ on doping concentration.(ii ) in contrast to ( i ), @x Math0 is strongly reduced by the kinetic energy of single or cooperate pair hopping, which correlates the reduction of @x math0 with the rise of superconductor stiffness, and hence@xcite the transition temperature.(iii ) long range magnetic correlations in rv b states are extremely sensitive to changes in
linear regression is one of the most common statistical techniques used in astronomical data analysis.   it is important to correctly account for both measurement error and intrinsic scatter when performing linear regression, as both aspects can have a non - negligible effect on the regression results. in this work  , i describe a bayesian method for handling measurement errors in observational linear regression. using a mixture of gaussians model,   my method models the distribution of independent variables as a weighted sum of gaussian polynomials, which allows flexibility when estimating the true distribution of the true values of the independent variable, thus increasing its robustness against model mispecification ( e.g., by using a suitably large enough number of Gaussians ). at the same time, our method also allows for measurement errors of different magnitudes ( i.e., ` heteroscedastic'errors ), non - detections, and selection effects, so long as the selection function can be modelled mathematically.
this article presents an mcmc algorithm for approximating the maximum likelihood ( ml ) estimator of a social network model, combining and extending ideas from gu and kong, snijders, and koskinen.   the method is applied to a series of repeated observations of a relation, or network, on a given set of actors, observed according to a panel design, and represented as a sequence of digraphs, where the observation moments are the nodes and the node set is the same for all observation moments. in the first part of the article,   we describe the definition of the model and the estimation method proposed in the papers mentioned ; the second part describes the methods for obtaining the ml estimator, and the third part presents the results of the selection of the best model for each observation moment.
the half - metallic ferromagnets of transition elements with group - v and vi elements ( respectively, pnictides and chalcogenides ) have been grown by molecular beam epitaxy on top of gaas substrates @xcite.   the growth of the binary alloy cras / gaas multilayers is shown to be very efficient and the size of the zb mnas islands at the fermi level is found to be in good agreement with the experimental results. for the first time it has been shown that the spin - polarization of the electron states up to the mendeleev s table @xmath6 is not affected by the presence of a spin - orbit coupling between the two groups of atoms in the x - ray structure of the compound. as a result, the spin magnetic moment of the r = 0.5  k values of the second and third periods of the mendleevs table are significantly higher than those of the first and fourth periods.
the atmospheric neutrino flux in the energy range 100gev400tev from the icecube experiment @xcite has been measured with unprecedented statistics.   the results show that the observed data are consistent with the predictions of the simulation of the background using the data, but the model implemented in simulation is inconsistent with the data and the predictions made by the experiment. to resolve this problem,   several possibilities have been explored, including the use of a sterile neutrinos as an intermediary between muons and electron neutrines.    we discuss the status of this effort and the potential for improved sensitivity to diffuse limits on cosmic neutrins.
the schrdinger equation of an interacting many - body system can be solved analytically only for specific interaction potentials and for a very restricted number of particles.   a wide range of approximation methods have been developed to determine the ground and excited states of many -body systems found in nuclear, atomic, and condensed matter systems. here  , we focus on quasi two - dimensional electronic systems, which are experimentally realized in quantum - dots. by separation of the two - electron case into the center - of - mass motion and the relative part,   semiclassical solutions have been constructed @xcite and compared to the exact solutions @xmath0-electron.conclusionsthe results of this study show that the excitation spectra of few - electron quantum dots can be accurately described by a combination of analytic and numerical methods.
the present paper is devoted to a general control strategy with the goal of stabilizing steady states of a broad class of higher order difference equations which include chaotic and non - chaotic systems.   the main motivation of our investigation is population dynamics where chaotic orbits coming close enough to zero can threaten population survival and cause unpredictable changes in a relevant food chain. here   we illustrate that, with target oriented control, it is possible to keep a controlled population at a prescribed level, certainly at a cost.
the problem of the orbital angular momentum of chiral fermionic superfluids in the bose - einstein condensate ( bec ) limit has attracted new attention due to the topological properties of these liquids and the related quantum anomalies.   the recently discussed effect of the edge states in the two - dimensional chiral superfluid has been discussed for general @xmath2, but the reduction of the angular momentum depends on the degree of the parity violation. here   we apply the general approach of the spectral flow through the gapless edge states to the situation, when the parity is broken or explicitly violated. within our model   it is shown that the eq (  ) for the ground state of the system remains valid even if parity is violated. however, for the boundary layer, the eq.( is also modified, but this time with a different degree of parity violation : the reduced angular momentum is suppressed due to spectral asymmetry of the fermionic edge states.
the role of the effective interaction in nuclear structure calculations at any excitation energy concerns is an aspect of great importance in the quasi  elastic peak region.   we investigate if different parametrizations of the interaction can produce noticeable differences in the results and the extent to which the use of an interaction fixed for a given effective theory affects the results obtained within a different one. using the so  called jlich   stony brook interaction, we show that the effects of varying the parameters entering in the zero  range piece of the non  tensor part of the effect are not as significant as those obtained with the same effective force of the second effective form. on the contrary, changes in the number of meson exchange potentials in the meson  exchange potential or the effective force used to adjust the interaction result in a decrease in the magnetic moments and transition probabilities in the neighboring nuclei.
the shape of clusters in percolation type models is an interesting physical property.   numerical simulations on random models have revealed that the shape of 2-d percolations at the percolating threshold is asymmetric which is a significant result, especially because of the close connection between Percolation model and the theory of second - order phase transition. in this paper   we address the shape for two - dimensional percolated clusters of self - affine models by evaluating their anisotropy parameters using fractional brownian motion ( fbm ) process as a measure of asymmetry. with the help of a fib simulation method, we present and discuss the results of our extensive numerical simulations of both random and self affine systems for the first time.we find that the mean square fluctuation of the distribution of the fbm process is proportional to the average of the spatial displacement of the host lattice and the average diameter of the cluster. when the distributions of the pore size are normalized from a normalized fbm distribution, the observed asymmetry is due to the existence of long - range correlations in the diffusion of the diffusion coefficients.    the results show that the anisotropic nature of the clustering
we report the construction of a new optical cavity qed quantum electrodynamic ( qed ) system that couples rb atoms and a finite number of modes of an optical cavity  @xcite.   the cavity is being constructed using two spherical mirrors with research electro - optics ( reo ) high - reflectivity coatings embedded in a single piece of macor, a low - outgassing ceramic that can withstand high temperatures. to increase the single atom coupling to the cavity mode, we decrease the mode volume by a factor of two and keep the decay rate of the cavity increasing the finesse also by a factors of two. however, the reduction of the volume complicates the collective strong coupling due to the distribution of transverse velocities of the atoms coming from the low - velocity intense source ( lvis ), which results in a broadening spatial profile and lower atom density as the beam propagates. to enhance the vibration isolation, we are constructing a new cavity with small and well - characterized losses, as well as slightly stronger coupling to each other and enhanced vibration isolation. for the first time  , we have used a 2-d optical molasses ( om ) to deflect an lvis
the recently revised aleph data for the vector and axial hadronic spectral functions extracted from @xmath0 decays led to renewed efforts to extract the strong coupling @x Math3 from these data.   these updates employ different methods : while perturbation theory and the operator product expansion ( ope ) are central to both, they differ in the way they treat resonance effects, or, equivalently, violations of quark - hadron duality ( dvs ). here   we provide a critical appraisal of the truncated - ope - model strategy, focussing on the most recent and very extensive application @xcite of this strategy to the Aleph data. using two different resummation schemes, fixed - order ( fo or fopt ) and contour - improved ( ci or cipt )  , we find that the value for @x math3 through this strategy is afflicted by uncontrolled systematic errors related to problems with its treatment of non - perturbative physics.
the asymptotics of high degree polynomials are well known from the work of hardy and ramanujan in 1917.   they discovered the zeros of a contour integral of the number of partitions of a positive integer @xmath3 by developing a new approach  the circle method " to handle such contour integrals which have dense singularities over the unit circumference. here   we show that this approach is particularly useful for the case of large numbers of zeros, such as those of the 25,000 degree partition polynomial where the coefficients have hundreds of digits.
the subject of one - atom maser and its optical counterpart, the one - atoms laser, has generated extensive interest after the recent experimental demonstration that they are capable of generating nonclassical states of the radiation fields.   the sub - poissonian nature of the cavity radiation field has been inferred from the fact that it has a variance less than that for a coherent state field. in the following,   we describe a unified formalism which shows that the one-atom maser ( micromaser ) as well as theone - atom laser ( microlaser ) cavity fields can have sub - Poissonian photon statistics. by taking into account the cavity dissipation and atomic damping, we show that the cavity field evolves under its own dynamics and is represented by a coarse - grained time derivative for the steady - state photon number distribution. during the decay of the two - level system, the cavity - mode and atomic decay constants   are assumed to be the same for both systems. using an exact numerical simulation of the dynamics, we find that the conventional laser dynamics is not suitable for looking into the possibility of generating fock states of these sub - possonian radiation fields since the damping of the
we investigate the damping rate of a massless fermion coupled to a scalar particle in a quantum field theory at high temperature using the braaten - pisarski method.   we find that the effective green s functions of the resummated propagators and vertices of the effective perturbation theory, which are used for the computation of damping rates of hard partons with momenta of the order of @xmath2 or larger, are logarithmic infrared divergent even using the resumed gluon propagator @xcite. this finding is consistent with the gauge independence of the results obtained by studying the effects of static magnetic screening on the vibrational properties of the resumed propagation.
the kinetics of the collapse of a long flexible polymer chain following an abrupt change of solvent quality is studied via a phenomenological model for the early stages of collapse.   the onset of collapse involves the formation of droplets of the dense phase, and the collapse proceeds via intermediate states corresponding to the " tadpole " configuration of a stretched, collapsed globule. with this picture in mind, it is possible to distinguish between four stages in the kinetic of collapse, which are characterized by a length - scale and a time - scale. at the end of the first stage, the chain as a whole is collapsed into a dense, spherical globule, i.e., the pearl necklace. at each stage,   its dimensions are roughly constant but the configurations of the bridges that connect the droplets are qualitatively modified. during the second stage, however, the structure of the chain is altered by the competition between the collapses of the individual chains and the aggregation of different ones. in the third stage, after the chain has been changed from a good solvent to a poor solvent, the bridge - stretching stage is followed by the shrinkage of the entire chain. finally, the final state is one of equilibrium in a poor
we investigate the existence of self - consistent equilibrium models that self - consistently generate the required density, potential, and anisotropy profiles encountered in dark matter halos.   we focus on the case of spherical models, for which a dynamical description simplifies substantially as in this case the phase - space distribution function ( df ) can be expressed as a function @xmath25 of the binding energy and the angular momentum. to obtain such dynamical models, we use a combination of two general 3-parameter models, namely the generalized nfw model (  ) and the generalized sic law model ( {zhao}/{sic } = {xmath2 } /{xmath3 }}. we find that these models satisfy the three universal relations mentioned above, i.e., the inverse power - law behavior, the scale - free nature of the density, and the linear relation between the logarithmic density slope and the radial velocity dispersion. using a variety of different types of equilibrated simulations, we also show that the dfs of the zhao model and the sic Law model are very similar.
quantum heat engines ( qhes ) have recently attracted great interest since it was originally proposed in @xcite. like their classical counterparts, these engines employ a quantum system as the working substance and run cyclically between two heat baths that are at thermal equilibrium at different temperatures.   we propose an experimentally feasible model of a single - ion qhe, that works like a reciprocating heat cycle, but maintains the always - on interaction with the bath, like in the continuous heat cycles in @xaite. for this model,   the electronic degree of freedom of the ion is chosen as theWorking Substitute s, while its vibrational degree offreedom plays the role of the cold bath, that also interacts with the ion throughout the entire cycle. to mimic the classical heat cycle in a quantum systems, the system interacts with a hot bath and a cold bath in an alternative fashion, during which it absorbs heat from the hot bath through its electronic state, and then rejects heat from both the baths through its vibration mode. using a local magnetic field that works as a  piston " applied to the ion, we show that the efficiency of this engine can be made close to unity by manipulating the driving magnetic field.
white dwarfs are the final evolutionary phase of low- and intermediate - mass stars.   they are degenerate objects and their evolution can be described as a gravothermal process of cooling. if axions exist, the properties of these stars would be noticeably perturbed since they have a relatively simple structure : a degenerate core that contains the bulk of the mass and acts as an energy reservoir and a partially degenerate envelope that controls the energy outflow. to test the evolutionary properties of white dwarfs, we have developed two new models of their evolution using data from the sloan digital sky survey ( sdss ) and the usno - b catalogue. in the first model,   the luminosity function of the white dwarf is derived from a sample of 3528 spectroscopically identified hydrogen - free da white dwarf spectra. for the second one, which is based on the results of the sdss data release 4, we used data from 6000 da and non - da white Dwarfs with accurate photometry and proper motions culled from the sds - ds data release 3 and the uv - visible spectrum of the same star, we obtained a monotonic behavior of the @xcite function
lmc x@xmath03 is a black - hole candidate ( bhc ) with an estimated mass of @xmath3.   it was observed with the optical monitor 30 in telescope on board _ xmm - newton _ on april 19, 2000. using the latest available matrix of colour transformation coefficients ( version 4, 2000 september ), we find that the companion star is a late - type star filling its roche lobe.
the interpretation of the number of lensed sources that are detected in a flux - limited survey depends critically on the factors by which the sources are magnified.   numerical calculations are valuable, but they tend to obscure the roles of competing contributions to what is being calculated. here   we show that the mean magnification of a singular isothermal sphere in an external shear field can be calculated analytically for both 2-image and 4-image gravitational lensing. using a simple elliptical lens model with circular symmetry, we derive the analytic expressions for all of the relevant quantities, including the meanMagnifications. compared to the full numerical evaluation of the magnification distribution,   our results are more accurate and more readily understood.
this paper documents some of the dynamics observed when a gas is injected into a shallow pool of liquid.   these dynamics are visible to the naked eye, but benefit from the high - frame rate and low exposure time offered by a high - speed camera. at low needle angles, the interface between the silicon oil and surrounding air is in static equilibrium. at higher angles,   the interface becomes both larger and more focused, developing into periodic jets. at sufficient jet height, the jets break into two drops, leading to both a high parabolic arch and a lower droplet stream. between ( @xmath5 )  , the jet dynamics breakdown so that the droplet streams appear chaotic.
quantum graphs are ideal models to study the questions of quantum chaology, as they exhibit the same rich variety of behaviors and share the same set of analytical tools as the more complicated systems.   however one can achieve deeper understanding on graphs while using methods which are simpler yet more rigorous. in the present paper   we aim to exploit the analogy between the tools used in quantum Chaology on billiards and graphs to analyze a recent breakthrough result by mller _   et al. ( @xcite ) that shows that the local statistical properties of the form factor of a generic quantum system resemble those of the spectrum of a large matrix from a suitable random matrix ensemble if the classical limit is chaotic. proving the conjecture of@xcite in any generality still remains one of the most exciting questions of Quantum chaology.
the solar photosphere and lower chromosphere are " line - tied " to the plasma in lower atmospheric layers where hydrodynamic forces can be stronger than lorentz forces, and coronal evolution is strongly coupled to evolution in these layers.   several techniques have been developed to derive flows from time series of photospheric or chromospheric vector magnetograms, @xcite, to derive the fluxes of magnetic helicity, energy, and free energy into the solar corona. here   we briefly review progress on estimating surface flows from magnetogram sequences, and demonstrate some aspects of the problem with test data.
comet 67p / churyumov - gerasimenko ( hereafter 67p ) is a bilobed body @xcite with a low geometric visible albedo of 0.069 @xmath0 0.002 and relatively uniform spectral colors.   these are typical of a dehydrated, organic - rich carbonaceous surface, although some areas that have been observed to be active show evidence of the presence of water ice. in this paper  , we present and discuss a hypothesis that may explain the characteristics of the early activity of 67p : thermal cracking of surface materials is operating faster on the neck because of the fast changes in temperature resulting from the shadows cast on it by its surrounding terrains.
reconnection in the earth magnetotail is a key step in the processes known as substorms.   reconnection converts magnetic energy stored in the magnetic field of the tail and converts it into heating and plasma flow away from the reconnection site, tailward and earthward. during reconnection,   the earthward flow is accompanied by a dipolarization front, a front of increased vertical ( north - south directed ) magnetic field that moves towards the earth and restores in part a less stretched and more dipole - like magnetic field in the night side of the earth. to understand the role of the interchange instability in perturbing this front, we perform a full 3d simulation of the system without seeding any structure along the direction of the exchange instability.. the results show that the interchange mode is self - consistently developing out of a reconnection region and that the dominant mode is the kinking flux rope warping.
the relaxation of the pd  er  h system induced by the hydrogen saturation is studied for the first time in the framework of macroscopic approach.   the model to be developed for the hydrogen induced relaxation in alloys based on pd has to take into account the stochastic evolution of the alloy structure and the difference in the rate of nonmonotonic structure transformations for different coherent diffraction regions, as it was noted for thefirst time in @xcite. at the same time, the mechanism by which these phenomena can be implemented is also discussed.
the inelastic neutron scattering structure factor of a molecular magnet cluster ( s=1/2 ions ) is calculated for the first time using the heisenberg model.   the structure factor is found to be very sensitive to the local geometry and interactions of the magnetic ions, and the results are consistent with those of previous studies of molecular magnets.
red supergiant ( rsg ) stars are extremely bright in the near - ir, making them potentially useful tracers of the chemical abundances of star - forming galaxies out to large distances. here   we present observations of rsgs in the dwarf irregular galaxy ngc6822 using the @xmath10-band multi - object spectrograph ( kmos ; *????   * ) at the very large telescope ( vlt ), chile.   the results show that the galaxy is a polar ring galaxy with a large extended stellar halo and an extended high - density ( hi ) disk containing tidal arms and a possible hi companion, as well as a population of remote star clusters aligned with the elongated old stellarhalo. for most of the stars,   their abundances are lower than those of their old stellar population, indicating that they have undergone recent interaction with other stars in the galaxy.  also, there is evidence for a relatively constant star - formation history within the central 5kpc @xcite with multiple stellar populations, including evidence for recent star formation in the form of a known population of massive stars and a number of hii regions.
the dark energy of the universe is currently accelerating.   the discovery in 1998 from observations of type ia supernovae @xcite that the universal expansion is accelerating was a spectacular result, and has since been confirmed by observations of the cosmic microwave background ( cmb ) and the large scale structure ( lss ). here   we review the current constraints on the sound speed of dark energy as well as the prospects for a future detection of this parameter. to achieve this we first review the formalism needed to describe the perturbation evolution of a general fluid with an equation of state and sound speed, then review the main observables which have measured the dark energy parameters so far, including the cmb, the lss, and the weak lensing. finally, we discuss the results of numerical calculations of the effective sound speed using synchronous gauge.
p systems are a type of membrane computing ( p system ) that mimic the workings of a special type of cell known as the @xmath6 cell.   it has been shown that snp systems, given their nature, are representable by matrices which can be implemented on parallel devices such as gpus. in this paper  , we present a matrix representation of the snp system, which is based on the fact that the working alphabet contains only one object type, and the number of spikes sent / received from one neuron to another, as well as the time elapsed between these spikes, is proportional to the amount of time spent waiting for each spike to reach the next neuron.. this representation allows design and implementation of an sn p system simulator using parallel devices like gpus, which are well - suited for the purpose since they are architectured for massively parallel computations.
the past decade has brought new insights into nonequilibrium statistical mechanics due to the discovery of various types of fluctuation relations valid arbitrarily far from equilibrium @xcite.   these relations identify, at the level of the single realization of a statistical ensemble, the " trajectory entropy " which upon ensemble averaging reproduce the thermodynamic entropy and quantify the statistical significance of nonthermodynamic behaviors which can become significant in small systems. in this paper, we extend the generating function ( gf ) method used for driven closed systems to driven open systems and derive three new fts, for the total entropy production ( ep ) and its nonadiabatic and adiabatic contributions, for systems initially at equilibrium with a single reservoir which are externally driven out of equilibrium by an external force. using the gf method, we show that these fts lead to exact inequalities valid arbitrary far away from equilibrium. here  , we propose to experimentally test these newly derived fts in a driven single orbital quantum dot where the various entropy probability distributions can be measured by the full electron counting statistics which keep track of the four possible types of electron transfer ( in and out of the dot through either lead ). as the driving is varied between the
we investigate the production of charm quarks in nucleus - nucleus collisions at rhic and lhc energies within the framework of the statistical hadronization model ( shm ) @xcite.   we provide an estimate of the magnitude of @xmath3 annihilation in the expanding quark - gluon plasma ( qgp ) and use the model to predict phase space distributions of quarkonia produced in these collisions.    we compare the results with sps data and with data available at rhia@xcite and provide predictions for the Lhc energy, where data are expected in about two years. in particular the situation at sps energy is significantly modified when taking into account the realistic reaction geometry. under this scenario,   the model predicts that the rate of charm production increases by about a factor of 3 beyond the perturbative quantum chromodynamics ( pqcd ) predictions, which are based on the assumption that all heavy quarks ( charm and bottom ) are produced in primary hard collisions and that their total number stays constant until they are hadronized. using the model, we show that the equilibrium temperature of the qgp is equilibrated near the critical temperature, @x Math4
the properties of a dipolar bose - einstein condensate ( bec ) in ring- and shell - shaped traps are studied.   the trapping potential is axially symmetric around the polarization direction of the dipolar bec in both types of traps, whereas the trap geometry is spherically symmetric in the case of the shell -shaped trap. for the ring - shaped dipolar Bec, the stability properties are more stable when the plane of the ring is aligned perpendicular to the polarization direction, than when it is aligned parallel to the polarized direction. in these traps, the anisotropic nature of stability properties in a ring - shape dipolarBec is further demonstrated by a consideration of the chemical potential of the system.
we study the effect of spontaneous chiral symmetry breaking induced by external magnetic or chromomagnetic fields on the phase structure of a ( 1 + 1)-dimensional gross - neveu ( gn ) four - fermion ( 4f ) model @xcite in the framework of the @xmath3 expansion technique.   we show that this phenomenon is due to the simultaneous transformation of the ground state of the model into a symmetric phase with respect to the following simultaneous transformations : ( 1+1)-symmetry breaking, ( 2+2)-sympathetic symmetry breaking and ( 3+3)-syndromic symmetry breaking. for d=1 + 1,   the results are in good agreement with the results of the nambu  jona - lasinio ( njl ) and gn - type models, where the dynamical generation of a fermium mass is considered as a consequence of the spontaneous breaking of the continuous@xmath2-symmedymmetry. however, it is necessary to point out that there is one more phenomenon that is still a well - known feature of only some low dimensional 4f theories, i.e., the duality correspondence between
the relativistic shell model for the propagation of a particle ( or hole ) inside a nucleus is introduced.   it is based on the green s function formalism, which allows situations where the kinematics of the initial and final nucleus can be different. in this paper   we consider the problem of two interacting particles, namely a nucleus @xmath2 a nucleon or ( if case ) an elementary particle ( nucleon ) @x Math2 a quark. to account for recoil effects in high energy nuclear reactions and in quark physics ( excitations of nucleon, meson ) we introduce a model with particle ( hole)-nucleus interaction, conceptually similar to the shell model. due to nuclear recoil   the equations for hole and particle become different unlike the infinite systems or models where recoil is neglected. by introducing the ground state of the system as the " shell "  , we are able to study the dynamics of the exchange of electrons and quarks in the presence of a nucleus in a more general way.
the discrete frchet distance is a distance measure used to measure the similarity of two polygonal chains in three - dimensional space ( 3d ).   recently, jiang, xu and zhu applied the discrete frhet distance in ( globally ) aligning the backbones of proteins ( which is called the _ protein structure - structure alignment _ problem ) in 3d and their results showed that this simplified distance is always realized by two vertices in @xmath8 and@xmath9. here  , we show that if many proteins are given then the local structure alignment problem, under the discreteFrchet distance, is very hard ; on the other hand, if only a small number of proteins were given then there is a polynomial time solution for the problem. among the various distance measures,   the hausdorff distance is one of the most widely used as a general distance measure in the field of abstract spaces because it is well known that it is polynomially solvable for restricted surfaces. however, very little algorithmic / complexity results are known regarding the protein local structureignment problem. in this paper, we present a new heuristic method for the protein global alignment problem
the quasiparticle random - phase approximation ( qrpa ) is a powerful tool for understanding collective excitations in open - shell superconducting nuclei.   it is particularly useful for the study of low- and high - frequency multipole modes when the neutron excess is unusually large, e.g. near the neutron drip line. here   we present a new method for applying the q rpa to collective vibrations in spherical nuclei, using a single skyrme energy functional, skm@xmath0, which exploits the entire particle continuum in a fully self - consistent way. by solving the hartree - fock - bogoliubov and hfb equations in a harmonic - oscillator single - particle basis  , we show that this approach is more accurate than the standard matrix formulation, which treats collective states in spheroids in coordinate space, and can be used to calculate the mean - field of collective vibrations as long as their amplitudes are small.
we construct two kinds of integrable impurities for a fermionic small - polaron model with general open boundary conditions ( bc ) using the graded version of the quantum inverse scattering method ( qism ).   the forward - scattering impurities are introduced by shifting the spectral parameters of local lax operators at arbitrary sites in the bulk and embedding the impurity fermion vertex at each boundary of the model. for well - separated impurity vertices located within the bulk, the local interaction terms involve the two neighbouring sites as usual @xcite. placing the forward scattered impurities at the back - scattering boundaries,   we derive a hamiltonian with rather general boundary terms which may be interpreted as sources and sinks of particles at the boundaries. using the yang - baxter equations ( ybe ) and the graded reflection equations ( re ), we derive the bethe ansatz ( ba ) equations and obtain expressions for the eigenvalues for special cases of the hamiltonians.. in addition, we discuss the ground - state properties in the thermodynamic limit.
the growth of schreier graphs of automaton groups is one of the central objects of study in geometric group theory.   the growth of cayley graphs ( growth of groups ) is a generalization of the action of a group on itself by the left multiplication, and is related to the asymptotic characteristics of the group such as the complexity of the word problem, the hausdorff dimension of the limit space, the exponent of divergence of geodesics in the associated gromov - hyperbolic self - similarity complex, etc. in this paper  , we consider the development of the family of orbital schreiers graphs of contracting automaton Groups. for every automaton group generated by an automaton over some alphabet @xmath1, the chain of finite schreies grows polynomially in the space of right - infinite sequences over @x Math1, and for every set of automata generated by a polynomial automaton, the number of paths of length avoiding the trivial state in the automaton grows exponentially in the same space. at the same time, all orbital sch reiers of contracting groups have polynomatic growth.. the degree of the growth
fast fourier transform ( fft ) is one of the most widely used operation in digital signal processing algorithms.   fft processors should be of higher throughput with lower computation time since the number of stage of fft computation increases with a factor of @xmath2. in the design of high throughput fft architectures,   energy - efficient design techniques can be used to maximize performance under power dissipation constraints. in this paper, we propose a novel architecture of area efficient fft by reusing @x Math3 numbers of butterfly units more than once instead of using @x math4 butterfly units once.    this is achieved by a time control unit which sends back the previously computed data of @Xmath3 butterfly units to itself for @x maths5 times and reuses the butterfly units from the previous times to complete fft computations.
we propose a distributed energy efficient power control algorithm for the uplink two - tier networks with small cells and massive multiple - input multiple - output ( mimo ).   the power control problem is solved by decoupling the energy efficiency optimization problem into two steps for the multi - user and multi - cell scenario. in the first step, we propose to assign the users into different groups based on evolutionary game theory ( egt ). In the second step,   multiple power control games based on egt are formulated for each group. then, each user in the two -tier networks can take individual decisions to optimize its own energy efficiency using the egt approach. as a result, the computational complexity can be greatly reduced in comparison with the brute force approach and the fairness among the users can be improved significantly.
the ability to simulate hydrodynamic flow is key to studying most astrophysical objects.   one of the outstanding and complex problems in theoretical astrophysics is the mechanism for core - collapse supernovae, which has been the subject of much debate for more than two decades. here  , we present a new hydrodynamics code, bethe - hydro, which uses arbitrary lagrangian - eulerian ( ale ) grids and a general gravity solver to address this and other outstanding astrophysical puzzles. using experimental data from the @xcite 2d mixed - frame radiation transport scheme, we show that bethe-hydroxy is a powerful and flexible numerical tool, able to configure the grid to suit the computational challenge and to achieve results that are comparable to those of vulcan/2d, the recently reported acoustic supernova mechanism.
type ia supernovae ( sne ia ) are the most important standardized candles for cosmology, and have been used to discover dark energy and the accelerating universe.   we use the two - component sn ia model of @xcite and the stretch distribution for each component from the supernova legacy survey ( snls ) data to quantify the expected magnitude of this effect, and compare the predicted evolution in lightcurve stretch to sn distributions from the snls and the higher - z sn search@xcite. using the results of these studies, we find that the population of slow declining, brighter, brighter sne ias come from a young population and have a rate proportional to star formation on a 0.5 gyr timescale, while the dimmer, faster declining, dimmer population comes from a much older population with a rates proportional to the mass of the host galaxy.    these results are consistent with the predictions of previous work using snls data.
we estimate the error rates for rna as a nanoscale data transmission medium, thereby permitting the design of efficient error - correcting codes, and ensuring the reliability of rna - based communication systems.   rna is an example of inscribed matter, in which genetic information is encoded into deoxyribonucleic acid ( dna ) and ribonuclear acid ( rna ), and transmitted by means of a single - stranded rna molecule. using this system,   large data strings could be conveyed from transmitter to receiver by dividing the data into packets, transmitting the data over the channel, and reassembling the data at the receiver.. however, rna replication is noisy, and it is necessary to have a mathematical model for the noise process in order to ensure that the code is reliable and efficient. here  , we present a new method for estimating the error rate for rrna replication, based on the fact that rna replicates are not perfect reproductions of the original. with the exception of the number of nucleotides in the rna strand, the errors in the replication process are very low. when the data string is encoded in rna, the average error rate
the draco dwarf spheroidal galaxy is a metal poor system with an @xmath0 } \rangle$.   we present our photometric results of 268 double - mode rr lyraes ( rrd ) and 8 anomalous cepheids from the @x Math2 and @x math3 bands.  in addition to the rrd stars, we have also identified eight anomalous Cepheid stars that are not known to be in the draco dwarfs.
we study the spectral properties of the area operator of loop quantum gravity @xcite numerically.   we find that the spectrum is discrete, but the mean nearest level spacing decreases for increasing eigenvalues. in order to get the density of states,   one also needs to know the multiplicities of the eigenvalue and the maximal value of the number of vertices, edges and irreducible su(2 ) representations ( or, correspondingly, by integer or half - integer numbers ). using the formulae obtained from the theory, we obtain the following results : the spectrum becomes asymptotically a straight line with respect to the sequential number of eigens, but this is not the case for small sequential numbers such as @xmath22.. the largest nearest level spacings occur between zero and the next state, which is @x Math23@xcite.
abstractthe study of the disruption of the ordering tendency in low - dimensional antiferromagnets at zero temperature and the subsequent emergence of unconventional phases is an active topic of research, on both theoretical or experimental fronts.   the search for microscopic models that potentially host spin - liquid plateaus formed in high magnetic fields is quite intriguing in the light of both the field control of spin liquids and a recent theoretical report @xcite. in this paper  , we will investigate the ground - state phases of the balents, fisher and girvin ( bfg ) model in the presence of a magnetic field, which, as we will see, exhibits large magnetization plateaus at magnetization per site@xmath0 and @xmath1 as well as the gapped spin liquid reported in ref. here  . these plateaus are found to be gapless when the value of total spin per unit cell is an half - odd - integer ( e.g., the spin-1/2 xxz model with extended interactions on the kagom lattice ) and the ground state is non - degenerate.
we report on a search for radio emission from the low - mass x - ray binary sax  j1808.43658 ( @xcite ;@xcite ) during the outburst and then also during quiescence at 1.4/2.5  ghz.   we find that the system is a low - field neutron star with a pulsar companion, which can be spun up to millisecond periods via accretion of material from its companion. in both cases,   the source of radio emission appears to be a continuum source, as observed by observing the system with the australia telescope compact array ( atca ; @xmath3, dec ( j2000 ) = 4.8/8.6  Ghz ).    the origin of the radio emission is discussed, and the implications for the evolution of millisecond pulsars are discussed.
the trace anomaly is a key quantity to study the thermodynamics of qcd  @xcite.   the trace anomaly signals the breaking of scale invariance in gluodynamics and qcd, and it is a crucial quantity for understanding the polyakov loop ( pl ) in the fundamental representation. while the interplay between the pl and physical observables has been considered obscure for a long time, recent advances have led to a description of the pl in terms of hadronic resonances, making a clear connection between this quantity and the spectrum of q cd  @xaite. in this communication   we will elaborate on this relation in gluminescence theory and provide a physical interpretation of the plasma pl in representations other than the fundamental one.
we report on silicon - based surface ion traps built for cryogenic applications.   the traps are designed to operate at cryogenic temperatures and are fabricated using intrinsic silicon as a trap material. by operating the traps at these temperatures, the charge carriers in the silicon freeze out, leaving the substrate as a good insulator with low radio - frequency ( rf ) power dissipation. this obviates the need for a shielding electrode and reduces the amount of power that is dissipated in the chip when the trap is operated at room - temperature. moreover, the traps do not need to have a ground plane to shield the substrate from the trapping rf field.
blue compact dwarf ( bcd ) galaxies are characterized by strong episodes of star formation as evidenced by the blue optical colors and the presence of bright emission lines in the optical spectra.   they span a range of metallicities that goes from about a third solar down to @xmath0/51 for i  zw  18, indicating a non - uniform star formation history possibly undergoing episodic bursts. here   we study the photometric and spectroscopic properties of bcds, their star - formation process, dust, gas and@xmath4 content as a function of the metallicity using deep multi - wavelength photometry and the nebular contribution spectroscopy.we find that the number of wolf - rayet stars in all three galaxies is increasing with the metalicity of the galaxy.    this is indicative of a recent and short star formation episode as shown by the evolution of the numbers of wr over the time course of the observed spectra at 4686    for tol  35, 3 and um  462, and by the observation of the changes in the mass of the redshift of the wurtz - like features at 486   and 4686
we present a new model for the roto / torsional dynamics of dna one, which is based on the y - model proposed by englander, kallenbach, heeger, krumhansl and litwin ( @xcite ).   the model is extended to include soliton - like excitations as well as travelling wave solutions, and we show that it is not only possible to obtain a nonzero value for the parameter @xmath1, but also that the qualitative form of soliton solutions is little changed with respect to the standard x - model ; as for their width, it is very moderately increased, still remaining in the same order of magnitude.
the adsorption of neutral water soluble polymers ( nwsp ), exemplified by polyethylene oxide and polyvinyl pyrrolidone, is modeled as two - state polymers whose monomers interconvert between hydrophilic ( p ) and hydrophobic ( h ) states.   these models differ with respect to the precise identification of the two interconverting states : polar vs apolar, hydrated vs nonhydrated, or clustered vs nonclustered. in the following   we investigate this problem using off - lattice monte carlo simulations supplemented by simple theory. within each case   the monomers are modeled as lennard - jones particles having identical collision diameters and the interactions between of the various monomer - monomer pairs are identical but the interaction parameters with the surface differ with the monomeric state. for the first case we show that the ph interconvesion of a single, terminally anchored, non - cooperative two -state polymer@xcite exhibits identical scaling behavior upon introduction of the appropriate effective adsorbed energy per copolymer s monomer, @xmath0, and then analyze the simulation data assuming that
high harmonic generation ( hhg ) is a highly nonlinear and non - perturbative process by which coherent harmonic photons of the driving laser are emitted, with harmonic orders ranging up to the extreme ultraviolet regime.   the intrinsic coherence of the hh g process can be exploited in the development of novel high performance light sources such as attosecond pulses. at the core of strong - field physics   is the recollision picture in which an electron, after being ionized, is accelerated and returned to its parent ion upon reversal of the electric field direction. following the decomposition of the process into three successive steps, one can intuitively expect the hHg cross section to factorize into the product of each individual step, as @xmath0 the ionization probability times@xmath1 the propagation, through the probability of recollisions, times @x Math2 the efficiency of rescattering.    in this paper   we introduce a semi - classical wavefunction that combines the wave / particle picture of the electron with a quantum - like delocalized wavefunction supported by a trajectory in phase space. using these combined perspectives  , we show that the dipole acceleration signal associated with rec
we present a renormalization procedure for calculating effective hamiltonians from the initial hamiltonian of a strong electron   phonon interaction in strongly correlated systems.   the method is based on continuous unitary transformations, which are applied to the problem of calculating the critical temperature of a superconductor using eliashberg theory ( @xmath0 ) and wegner's method ( @xcite ). as a proof of principle   we show that the proposed method can be used to calculate the energy scale that determines the critical temperatures of superconductors with high accuracy.
we present a new approach to constructing stringy products for global quotients using a mechanism that first pushes forward and then pulls back.   we show that in the case of cyclic twisted sectors both approaches exist for all the geometric functors considered in @xmath1frobenbenius algebra structures. this allows us to prove the relevant theorems using only the projection formula. in the derham setting,   all the elements of the previous study hold up to homotopy, that is up to exact forms. hence we can provide a rigorous setting using formal fractional thom push  forwards and pull  backs for general global quotient calculations.
the kitaev model is the simplest model that realizes majorana zero - energy states ( mzes )@xcite.   it well describes a one - dimensional nanowire with strong rashba spin - orbit interaction@xmath4-wave superconductor and the zeeman field. in this paper, we investigate a system where one - dimension topological superconductors are placed in parallel, where the superconducting pairing phase can be changed arbitrarily. by changing the magnitude of the interlayer hopping,   the number of the mzes changes from @xmath11 to @x Math12 by changing its relative phase. when the relative phase between the inter- andachain superconduction pairings is @x math12 or @x maths0, the system belongs to the class bdi and is characterized by the @xMath1 index.    otherwise, the systems become class d and are characterized by an arbitrary number of mzes due to the level repulsion by the interchain supercondensation of the two subbands.the results show that the system behaves as a single - dimensional topological quantum quencher with a single majorana fermion in each of the chains.
we present a novel characterization of comtraces using labeled so - structures.   the notion of comtrace is introduced by janicki and koutny ( @xcite ) in the book of traces, where they introduce the concept of _ stratified order structures _ ( _ so - structure _ ).    we show that every comtrace can be represented by a labeled so-structures.. however, the converse could not be shown because a class of labeled so--structures that defines precisely the class of comTraces was not known. to address this issue,   we propose a new definition of com trace as a finite set of congruent step sequences defined by a set of binary relations. here  , we demonstrate that the definition is valid for all labeled so -- structures that are used to model both the  earlier than " and  not later than " relationships in the most well - known class of partial orders, i.e., step sequences.
supermassive black holes ( smbhs ) are a standard component of elliptical galaxies and spiral bulges.   when galaxies evolve through hierarchical merging, each smbh participates and at some point forms a hard binary. in this paper  , we explore the possibility that the high velocity planetary nebulae ( icpne ) found in m87 were ejected after interacting with a supermassive binary black hole at the center of m87. using a high resolution n - body simulation of a cluster potential, we model the ejection velocities of the stars that pass between the two smbbhs and study how well the ejected population remains kinematically distinct within a clumpy and still evolving cluster potential. according to our models,   the ejected stars are more likely to be metal rich than those stripped by dynamical interactions between galaxies ; they are most likely to have distinct kinematics and spatial structure. as a result, we find that the mass fractions of the stellar component of the cluster potential generated by 3-body interactions are significantly higher than those generated by tidal interactions. during the hard binary phase, these ejected stars may constitute a different type of stellar population than the ones stripped by tugging or tidal stripping.
the local interstellar medium ( ism ) is thought to be a low density cavity in the solar vicinity.   the size of this cavity has been shown to be in the range 50 - 100 pc by @xcite and @xmath8. here   we use the hipparcos catalogue to estimate the diameter of the cavity using the average line of sight reddening / extinction parameter, @x Math9. for stars with a spectral type but no luminosity class we use an intrinsic color diagram to distinguish between the dwarfs and the giants. from this we estimate the distance between the two groups of stars and find the location of the largest reddenings in the spectrum of the stars with the same spectral type. as a result   most stars with positive parallaxes have red shifts in their intrinsic position that are not caused by extinction. when one or more of these reddenments are changed in a significant way the boundaries of the bubble are clearly visible.
this paper proposes a data - efficient approach for predicting the motion of an object under physical interaction by utilizing a physics engine and learning the physical parameters through black - box bayesian optimization.   first, a real robot is used to perform some random pushing action with an object on a tabletop. instead of learning the object s motion explicitly,   a bayesian optimized technique is used in the simulation to identify relevant physical parameters, such as mass and friction, through the physics engine simulation. to predict its motion under a new action, the learned parameters can be used to simulate the action in a physics Engine.    the results of this simulation can then be used by the robot to predict the effect of its action on the object. to solve the challenge in figure  , the same bayesian optimize technique is also used to search the optimal control policy for the robotic hand pushing the object.see research article http://www.biomedcentral.com/1471-7007/9/8/17
bespsel beams are a class of non - diffractive light waves that have been extensively studied over the last two decades.   they exhibit several intriguing properties, such as diffraction - free propagation of the central peak over a distance fixed only by the geometry of the source device, and superluminal phase and group velocities in free space. here  , we report a complete characterization of spatio - temporal properties of an optical bessel beam generated by reflection from a conical mirror @xcite. with respect to commonly used axicons@xcite, the beam propagates with a coherent superposition of equal - amplitude, equal - phase plane waves whose wavevectors form a constant angle @xmath2, called the axicon angle, with the direction of propagation of its beam which we define as the @x Math3-axis. at propagation distances greater than @x math16,   the beam diffracts very quickly, spreading the energy over an annular region.the results show that the beam can be produced by a single pulse of a continuous wave ( cw ) he : ne laser operating at a wavelength of @x maths21 using a monte carlo technique.
the yukawa couplings in the standard model of particle physics ( sm ) @xcite are fixed by the renormalisable superpotential @xmath4 w_{p_6 } & = & \left(h^e_{ij } l_i^a h_d^b { \bar e}_j   .   + h^d_{ij ] q_i^{i^ a h_ d^b{ \bar d}_ j } + \mu h_D^ah_u^b \right)\, the same is true for the proton decay operators@xmath5 and @x Math6.    we introduce the discrete symmetry, proton hexality, @x maths15, which prohibits both @x math16 and @Xmath17, as well as the dangerous dimension-5 proton decays operators @xcitedite ; this is the minimal supersymmetric standard model ( mssm)@xcite. 	 we also introduce the baryon - triality @xMath19, which allows for non - zero neutrino masses without the need for right - handed neutrinos. at low - energy
quantum chromodynamics ( qcd ) critical end point ( cep ) is a landmark point in the phase diagram of qcd at non - zero temperature.   it is also a key component of the classical hadron resonance gas ( hrg ) model of quantum chromodynamics. from the experimental side,   there is no conclusive evidence about the location of the cep. here  , we report the measurements for the highest order moments of net - proton and net - charge event - by - event distributions using the beam energy scan ( bes ) phase - i data of relativistic heavy - ion collider ( rhic ) with the focus on taking data at lower beam energies ( below 39 gev ) to explore the role of quark gluon plasma ( qgp ) phase in the evolution of the qcd phase diagram at low and high temperature. as one approaches the cecp, the ratio of strange to non - strange susceptibilities calculated in lattice qcd shows a variation with the temperature which are correlated with the changes in relevant degrees of freedom of the system. among the quarks and gluons that carry the strangeness degree of freedom, the most important ones are qu
circinus  x-1 ( cir x-1 ) is a peculiar x - ray binary, which is thought to be a low - mass neutron star ( lmxb ).   the high energy spectra of cir  X-1 have been poorly understood. in this work, using the pca and hexte observations on board the rxte, we investigate the evolution of broadband spectrum ( 3 - 200 kev ) of liverinus X-1 along its hardness - intensity diagram ( hid ) from the vhb, through the hhb and nb, to the fb with the use of the standard mode 2 data of the asca and standard modes ( pca + hexte ) of the psa and asca+hplc2 satellites. by analyzing the spectral evolution of the broadband spectrum at different points along its hid, we show that the time lag between the complete hid and the apoastron shows a strong correlation with the magnetic field strength of the outermost part of the central region of the star.. the observed time lag seems to be consistent with the comptonization model with a two - layer corona.
the resonant intensity - dependent jaynes - cummings model is a generalization of the ordinary jayne - cum mings model.   it allows the generation of well - defined schrdinger cat - like states during the evolution of the field in the model, i.e., the transformation of a statistical mixture of two coherent states into a quantum superposition of coherent states. in this paper   we are going to be concerned with the dynamical change of field states, namely superpositions of coherent state.    surprisingly enough we have found that the resonant intensities of the vibrational coupling between the field and its environment can be used to induce the purification of an initial statistical mixture into an odd - coherent state at half the time of the revivals for an initial coherent state @xcite. because of the full periodicity of the model again, the atom returns to its initial state ( the excited state, for instance ) at the second revival. however, at the first revival the atom will invert its state, ie, it will appear in the ground state. on the other hand, if we start with the field prepared in a ( pure ) even - coherence state,
the one - loop corrections to the dirac form factor of the @xmath1 expansion of the chiral lagrangian for baryons are studied using heavy baryon chiral perturbation theory and lattice qcd.   the theoretical expressions obtained in the analyses agree well with experimental data, providing strong evidence that the combined chiral and @x math1 expansions work well for beryons.
the quantum fluctuation of island charge in the coulomb blockade ( cb ) regime of the single - electron transistor ( set ) is investigated using the keldysh formalism.   the current noise and the charge noise are investigated in the regime of large quantum fluctuations, i.e., the second moment of the fluctuation operators. a theoretical framework for the calculation of the higher order correlation function of the current fluctuation operator   is constructed and applied to the problem of the quantum fluctuations in the two - state limit of set where the tunneling conductance is so small that it is impossible to observe the high order quantum fluctuated charge at the interface between the source and the drain junctions. as a result, the results show that the charge density in the non - equilibrium state is much smaller than the typical level spacing of charge states, which is due to the renormalization of the conductance and the charging energy below the kondo temperature. with this model, the life - time broadening of a charge state level is much less than the usual one, and the structure of the structures of the characteristic@xcite characteristic is also smeared.
quantum discord ( qd ) is a measure of quantum correlation, which characterizes the quantumness of correlations more generally than entanglement.   quantum discord under decoherence has attracted much attention in recent years, because this study is expected to supply some insight regarding how to overcome the detrimental effects caused by deco coherent states on quantum correlation. here  , we propose a scheme to stabilize qd by appropriately engineering the reservoirs to introduce the non - markovian effect, an issue actively studied recently @xcite. by studying the correlation dynamics of a continuous - variable bipartite system,   we show that a finite gaussian qd can be frozen in the steady state and that the essential physics is the formation of a localized mode in the subsystems and the non-markovian dissipation effect. using a coupled cavity array system realized especially in a photonic crystal system, the experimentally accessible scheme is proposed to observe the frozen qd.
we investigate the overload breakdown problem for vertices in growing networks with an emerging power - law degree distribution.   we use the standard model for such networks  the barabsi - albert ( ba ) model  but with a maximum load capacity assigned to each edge, and define the load by means of the betweenness centrality  a centrality measure for communication and transport flow in a network. using this measure we find that the number of vertices sensitive to overloading increases with the increase in the amount of load on the edges of the network as a function of the distance between two vertices or the time it takes to add new vertices. at the end of the process of adding edges,   the effect of the preferential attachment is more pronounced than that of the random attachment.
many previous works strongly suggested that the original masses of very massive stellar systems ( fg ) should be at least 10 times more massive than the present masses of gcs in order to explain the observed large mass fraction of new stars ( sg ) in the galactic gcs.   however, their models are based on one - dimensional hydrodynamical simulations and have limitations in predicting 3d structures and kinematics of final stellar systems. in this letter  , we show that the kinematical properties of sg can be significantly different from those of fg based on self - consistent 3d hydrodynamic simulations on star formation within forming gcs with different stellar populations. in particular, if originally very massive gcs ( fgs ) have only a small amount of rotation, then new stars formed in the central regions can have a significant amount of rotational rotation depending on initial kinematic properties of fgt. based on these results,   we point out that the origin of internal rotation observed in the Galactic gcs can be closely associated with formation processes of Sg in original massive stellar system which can be either very massive super - star clusters or dwarf galaxies.
in the seminal work  @xcite, wolfenstein explored the possibility of a change in the dynamics of neutrinos based on coherent forward - scattering with surrounding matter particles. in this paper, we investigate the influence of the finite decay width of the gauge boson on the energy of the neutrino self - energy.   we derive the propagator function from thermal field theory and give arguments how a resummation of the series in eq. (  ) changes our results.    furthermore, we apply it to the cases with and without finite decaywidth. in a thermal background,   a new energy scale enters ( this scale is of order 1  kev if we consider neutrines in the sun up to order 1 mev for the cosmic neutrini background at decoupling ) that will change the influence by the finite fallacies of the w - boson.
the lorentz - fitzgerald contraction ( lfc ) is a simple space - time geometrical effect that is apparent only if the moving object is viewed in a direction strictly perpendicular to its direction of motion.   the present paper shows that the ` real'and'apparent'positions and sizes of moving objects are distinct, and that the lfc is not a'real'effect. as first shown by einstein in his seminal paper on special relativity ( sr )  , this is the case because the apparent lfc effects are derived from the Lorentz transformation ( lt ) equations, which are correctly derived for the proper distance between two isolated material objects in a common inertial frame. when the lt is used to calculate the distances between two moving objects, however, it is not possible to distinguish between the real and apparent sizes and positions of the moving objects. here   we discuss the reasons for this confusion, and point out that the `` real'position and size of any moving object can be calculated using the lfcs obtained from the measurements of its apparent dimensions.
the flux flow oscillator ( ffo ) is a device made with a long josephson junction biased by a d.c.   current and driven by the effect of a magnetic field, perpendicular to the length of the junction and parallel to the barrier, into a dynamical state in which the unidirectional motion of flux quanta takes place. as the signal generated by a local oscillator has to be coupled to a mixer or to a transmission line, in the literature different couplings to a load have been realized and studied @xcite. in this paper   we investigate and compare these two coupling techniques for an ffo. since the frequency of the ffo signal is proportional to the magnetic field within which the flux flow dynamic state is stable, capacitive coupling is more efficient than direct coupling, since it allows to increase the power transferred to the load without the use of the d. c. block between the oscillator and the load device.
the search for the higgs boson at the large hadron collider ( lhc ) is a major priority.   the phenomenology of the standard model ( sm ) higgs decay is dominated by the relatively weak yukawa couplings, which are characterized by the ratio of light fermion masses and the vacuum expectation value ( vev ) of the high - gauge boson. in this paper  , we show that the use of boosted higgses analyses to non - standard higgs decays can have a dramatic impact on the reach of the lhC, not only in the @xmath16 channel, but in the notorious @x Math21 channel as well. given the size of the data set, we find that discovery significance can be achieved in both channels for significant ranges of @x math11 masses with more than 100 fb@xmath4 of data.
abstractthe muon momentum space in showers initiated by proton primaries is investigated in an eas experiment, combining field detector arrays with muon tracking detectors.   it is shown that the measured value of the tangential angle @xmath1 reflects the amount of muon scattering in the atmosphere and any relevant absorber / detector material, together with a possible displacement of the muon production place from the shower axis. using simple trigonometry and substituting tangent for an angle, what is correct within 5@xmath3 error up to @x Math4,   one can write the following expressions for @x maths1 and @x math2 :    0.5 + 1.0 + 2.0 = 3.0  gev / c, which are the angles between the shower direction and the orthogonal projections of themuon track onto the tangentially and radial planes, respectively. since the precision of the measurements in the air shower depends on the accuracy of the angular measurements, and, in particular, on the high energy muons tracking accuracy, one would like to have as large content of high energy Muons in the analyzed data sample as possible, one can use the
a real in the unit interval is computably enumerable if it is the limit of a computable, increasing sequence of rationals.   a real is ( algorithmic ) random if its binary expansion is an algorithmic random ( infinite ) sequence @xcite. for every universal machine @xmath0, the halting probability of a universal machine such that zermelo - fraenkel set theory with choice ( zfc ) can determine the value of only finitely many bits of @x Math1, and one can calculate a bound on the number of bits of@xmath1 which zfc can determine by tuning the choice of the halting probabilities of all universal machines @x maths0, @x math1 and @xMath2.. we show that the halting Probability of each universal machine depends on the representation of the c.e.   random real, and this dependence is not always the same as the entropy of the entire set of algorithms.
we study the electrical and magnetic properties of rippled graphene by solving self - consistently the hubbard model.   we show that the system is magnetically unstable in regions with a moderate hubbard interaction, which opens an exchange energy gap, favoring a local ferromagnetic ( fm ) order. for larger values of the on - site hubbard coupling,   the system gets a nel order with a very weak fm modulation.
the history of the universe and its star formation rate ( sfr ) is closely related to the metal enrichment history and the cosmic chemical evolution.   we present a new model of the star formation history based on a power - law model of galaxy evolution with a redshift dependence, which takes into account the observations of the relic @xmath3 neutrino background from supernovae. in this model   the total number of stars formed until today is about 10 times higher than it is today and the maximum of sfr takes place at a redshifts of order unity, where overall rate was about 10-fold higher than that of the present day. for the most recent work by madau et al. ( 2014 )    we have used the data from the 2df galaxy redshift survay survey to estimate the sfr as a function of the rate of supernova formation and the redshift of the galaxy. using our model we find that the peak of the current sfr depends on the model parameters but half of the stars have formed at redshifting higher than @x Math16.    we also find that there is a break at
the near - infrared galaxy luminosity function is an important characteristic of the local galaxy population.   it is a much better tracer of evolved stars, and hence of the total stellar content of galaxies, than optical luminosities which can be dominated by young stellar populations and are also strongly affected by dust extinction. in this paper   we combine the 2-micron all sky survey with the 2df galaxy redshift survey to create an infrared selected redshift surveys subtending  deg@xmath12. within this area   the complete survey is complete to the magnitude limit of the catalogue and so constitutes a complete survey which is 50  times larger than the previous largest published infrared selected Redshift survey. using the data from both surveys  , we show that the inferred luminosity functions are not affected by surface brightness selection effects and that they are more directly related to the underlying stellar mass of galaxies than the observed ones.
the conductance properties of self - assembled mono - layers ( sam ) are studied in the context of the geometrical alignment of the molecule and the fabrication of the device.   the results for three qualitatively different constitutions of the mono - layer are compared with experimental data. by this   we can rule out all but one of the explanations previously proposed to explain the occurrence of additional structure in the conductance - voltage ( @xmath1 ) characteristics of a sam, being build of 1,4-phenylene diisocyanide ( pdi ) and sandwiched between gold leads. using the method we use ( based on esqc@xcite ) for calculating the conductation properties of molecular devices, we find that the only geometric alignment, which gives rise to several peaks in the conduction curve, is a mono - layer with additional molecules perturbing the periodicity.
the origins of the light elements li, be, and b ( libeb ) differ from that of the other nuclides.   most elements are formed in stars, but libeb are rapidly consumed by radiative capture reactions in stellar centers and must therefore be synthesized in cooler or more tenuous environments. to test the @xcite model of the origin of libeb, we measured the angular distributions of @xmath11 ejectiles from the @x Math12 reaction for alpha energies between 159 and 620 mev, and integrated these distributions to obtain the total production cross sections for masses 6 and 7.    we find that the cross sections fall rapidly, essentially exponentially, with increasing bombarding energy, becoming small enough that@xmath13 will not contribute significantly to cosmic ray nucleosynthesis at energies above the measured range ( to 620 mevs ).. the results are consistent with the theory that @x math2 is responsible for the production of @Xmath10li, since the interstellar medium contains little cno in the early galaxy.
galaxy clusters are self - similar, and so they are expected to be scaled - down versions of the more massive systems.   we have measured the redshift of a large homogeneous subsample of galaxy clusters selected from reflex, a flux - limited x - ray selected cluster catalogue built under well defined selection criteria. in this study, we find that the slope of the @xmath1 scaling relation between the galaxy mass and the galaxy velocity dispersion is significantly lower than previously reported for all southern galaxy clusters ( h@xmath24 km s@x maths3 mpc@x math3 ).. the slope is most likely due to the presence of multiple galaxies in the sample, which can be explained by the fact that the density of the galaxy clusters is reduced by the collapse of the dark matter haloes through gravitational collapse.
we study the thermodynamic properties of strongly interacting matter at low temperature and density using 2 + 1 flavor polyakov loop extended nambu  jona - lasinio model ( pnjl ) with eight - quark interaction.   we find that the quark number and isospin number fluctuations increase with temperature and their fourth moments start to show pronounced peaks in the transition region from low to high temperature @xcite. for the small net baryon number, which can be met at different experiments, the transition from hadronic to quark - gluon - plasma ( qgp ) phase is continuous and the fluctuations are not expected to lead to any singular behavior.
accurate prediction of finite amplitude acoustic waves traveling through biological media is essential in developing new therapy and imaging techniques for medical ultrasound applications.   the aim of this work is to present a numerical method that solves the complete set of equations ( continuity, momentum and state equations ) including nonlinear propagation and frequency power law attenuation based in multiple relaxation processes.the numerical method presented here is based on the finite - differences in time - domain ( fdtd ) method which avoids convolutional operators so only one extra field per relaxation process is needed and no memory buffer is needed.the proposed method is validated comparing the numerical results with known analytic solutions for linear and nonlinear regimes.
the variable coefficient nonlinear schrdinger ( nls ) equation and its generalizations @xcite can be transformed into a constant coefficient nls equation by transforming it into a gross - pitaevskii ( gp ) equation. from the known solutions of the latter equation,   various localized solutions, in particular various localized profiles, have been identified for the model (  ), including soliton, breather, and rogue wave ( rw ) solutions.   this review focuses on the relevance of these localized structures for the problem.
we study the effect of self - interacting dark matter on the strong gravitational lensing properties of galaxy clusters.   we use ray - tracing through high resolution simulations to compute lensing cross sections for arcs of various types in a set of five different resimulations of the same cluster - sized halo, which is the second most massive object in the gif-@xmath6cdm simulation of kauffmann et al. ( 2000a, b ). using this method, we find that the collision cross - sections of the arcs are smaller than those of the central density cusps of the cold dark matter haloes and that the number of low - mass subclumps orbiting within the halo is reduced by a factor of 10 to 50 compared to the observed values. from the results of our analysis, we conclude that the observed observations of strong lensing by galaxy clusters are not compatible with the observed properties of the dark matter halo.
the quasinormal modes ( qnms ) of the schwarzschild - ads black hole are studied in terms of the ads / cft conjecture.   the theory of the perturbation damping time of the black hole in an anti - de sitter ( ads ) spacetime is solved for a newman - penrose ( np ) null tetrad frame with a negative cosmological constant, and the differential equations governing the axial and polar perturbations are solved using schrdingerlike equations.    the results show that the qn frequencies of the highly damped overtones in the ads spacetime are strongly damped at intermediate times, and they are not related to the wave numbers of the quantum waves. on the other hand, the frequency of the pure imaginary frequency is not proportional to the horizon radius in the large black hole limit as it happens for ordinary modes.
x - ray crystallography is a method for imaging molecules with atomic resolution.   the usage of x - ray free electron laser ( xfel ) in femtosecond nanocrystallography involves sequential illumination of many small crystals of arbitrary orientation, and the success of the procedure for pattern determination depends on the robustness of the indexing algorithm used to determine the orientation of the diffraction data from a single crystal when a relatively large number of reflections are recorded. here   we show that using corrugated structures in the last chicane of the linear accelerator can increase the radiation bandwidth of the electron beam by tenfold at photon energy 5.4 kev compared to the baseline configuration of the european xfels.    for this study we have developed an analytical _ modal _ representation of the short - range wake function of the flat corrugation structures for arbitrary offsets of the source and the witness particles. ’ this representation is different from ones published so far,  @xcite-@xcite,  and agrees well with the numerical results obtained by direct numerical solution of maxwell s equations for electron bunch shapes of our interest.
we estimate the average gravitational wave ( gw ) energy production from core collapse supernovae ( ccsne ), neutron star ( ns ) births and black hole ( bh ) births.   we use three different generic average source spectra to estimate an upper limit for the average gw energy production in the frequency band @xmath6 to be ~100 hz. using the cosmic star formation rate ( csfr ) as a parameter, we estimate the number of events per unit time within the comoving volume out to redshift z : @x math9 where @x maths9 is the cosmological background density, and @x Math12 is the stellar initial mass function ( imf ). for each of these parameters, we find that the rate of ccsn birth is about 1.5 times higher than the rate predicted by numerical modelling. on the other hand,   the estimated rate of ns births is about 0.1 times lower than the expected rate based on the theoretical model of the origin of the x- and y - ray emissions from the most numerous likely sources, e.g., pulsars, deformed nss, gamma ray bursts and coalescing compact binaries.
electron beam induced current ( ebic ) is a powerful tool for measuring material properties such as the minority carrier diffusion length and surface recombination velocity at the grain boundary core of polycrystalline photovoltaic materials.   previous models of ebic in single crystal materials have assumed that the ebic response for excitations in the @xmath0-@xmath1 junction depletion region is maximized at thegrain boundary core @xcite, but experiments show a nonuniform response throughout the absorber which is well below this assumption. to validate the relevance of the model, we present experimental data on si solar cells prepared by cleaving and focused ion beam ( fib ) milling where the sample surfaces are prepared with cleavage and fib milling. using 2-d numerical simulations, we find analytical expressions and numerical results for the ebia collection efficiency which includes recombination from neutral and charged surfaces. to verify the relevance between the model and the experimental data, we also present experimentally measured ebic data on the fib - prepared sample where the samples are prepared by milling the surface with charged defect levels. here   we show that the results are most consistent with the model of ebi response in
clusters of galaxies are very versatile tools for various types of analyses.   they can be used to determine cosmological parameters as well as physical processes on large scales and extreme environments. out of this large field   we select here mass and dark matter measurements, determination of the dynamical state and the investigation of the interaction between the cluster galaxies and the intra - cluster gas.
diffuse emission in the mid - infrared ( mir ) is a rich source of information about the structure of the interstellar medium, but it is difficult to interpret the observed intensity maps of diffuse emission as information about column density.   we investigate the appearance of a model molecular cloud in the radiation field of a nearby uv - source, in order to quantify the correspondence of various measures and tracers between the original column density maps and the derived flux density maps. for the highest density range ( up to @xmath8@xmath1 ), where the flux densities bear no resemblance to the column density, the structural properties of the original columns are found to be in good agreement with the derived maps. however, for the lowest density range from @x math7@x Math1, the results are not always consistent : the models show that the formation of shells, bubbles, filaments and dark clouds in the mir can be explained by irradiation effects, self - extinction and shadowing effects in the uv.
the rex linac is being upgraded to a high energy electron beam ion source ( hie ) with the addition of a new 7-gap resonator and a re - buncher in a bunching mode.   the aim of the upgrade is to improve the performance of the longitudinal emittance measurement of the rfq at 300 kev / u by means of the three gradient method behind the resonance energy quenching ( rfqs ) and the second 7- Gap resonator at 1.92 mev /u using the re - Buncher and the third 7- gap resonator in a pairing mode and by combining the switchyard dipole magnet and quadrupole on the 65@xmath0 beam line to form a spectrometer, which will be used to measure the transverse emittance of the electron beam along the linac.
turbulent convection is one of the major uncertainties in our understanding of stellar properties.   it affects the stellar structure and evolution significantly. because of its high non - linearity and complexity, we cannot solve the turbulent flows analytically at present. since @xcite established the first practical model of stellar structure, a lot of effort has been made to study the problems of stellar convection using the hydrodynamic equations. along with the development of digital computer and computational fluid dynamics ( cfd ),   numerical simulations have become an essential tool for the astrophysical fluid dynamic community. here  , we review the current state of the art in the field of numerical investigation of turbulent flows.
nonlinearities prevail in fluid dynamics when the reynolds number, @xmath4, is large.   simulations of turbulence are always carried out in regions of parameter space far from the observed values, either with : ( a ) an unphysical lack of scale separation between the energy - containing, inertial, and dissipative ranges while parameterizing the missing physics, or ( b ) a study of the processes at much smaller length scales, often with periodic boundaries ( unphysical at large scales but used under the hypothesis of homogeneity of turbulent flows ). to model the effects of the unresolvable small scales in turbulence on the scales resolved in the simulations, two main approaches have been developed over the years : large eddy simulations ( les ) and regularization modeling ( sgs ). here   we review the results of both approaches and discuss the advantages and disadvantages of each.
the gauge scheme interactions of the vector mesons with quarks and mesons are analyzed.   it is shown that the gauge scheme based on @xmath0 group is the simplest one to consider the light unflavored vector meson,@xmath6 and @x math7, together with the photon, as the gauge fields.. the gauge system is used to construct an effective model of the low - energy meson interactions using the quantum field principles. in this model,   the initial quarks with current masses transform to the constituent ones with effective masses, including some contribution of the internal gluon substructure. for the electromagnetic and strong ( vectorlike ) interactions, an appropriate vector fields are introduced as a gauge field realizing some dynamical symmetry. at the same time, the extra groups of the total gauge group are introduced for the gauge realization of the scalar meson dominance.
an epidemiological line list is a listing of individuals suffering from a disease that describes both their demographic details as well as the timing of clinically and epidemiologically significant events during the course of disease.   these are typically used during outbreak investigations of emerging diseases to identify key features, such as incubation period, symptoms, associated risk factors, and outcomes. traditionally, line lists have been curated manually and have rarely been available to epidemiologists in near - real time. here  , we present * guided deep list *, a novel framework for automatic extraction of line list from publicly available who bulletins. using neural word embeddings based on semantic dependency parsing,   the user provides a seed indicator ( or, keyword ) for each line list feature to guide the extraction process. when the seed indicator is expanded, the extracted line list features are used to infer the demographic distribution and symptoms - based characteristics of the population affected by the disease. with the help of this framework, we have generated a line list of middle eastern respiratory syndrome ( mers ) outbreaks in saudi arabia using public health bulletins from the world health organization ( who )..database url : http://www.ncbi.
recently atlas reported some excesses in the stop search with @xmath4 channel  @xcite.   we study the interpretation of the excesses as light stop pair production in the minimal supersymmetric standard model  ( mssm).we show that the simplified models where stop decays into a higgsino or a bino are not favored by other stop searches while extended models could provide a better fit to the excess.
directed and elliptic flow measurements at the full beam energy of 158  agev were published by na49 in 1996.   we have used the data from 120k minimum bias centrality events to reconstruct the flow of pions and protons at the same energy for three different centrality selections : 12.5%-33.5% central, mid - central and 33.5-100% peripheral. as required by symmetry directed flow of proton pions at 40  ageV vanishes at midrapidity and its magnitude increases towards projectile and target and it increases from central to peripheral collisions. for protons   there is a quite flat plateau around midrapidity. at 158   agev it seems to be positive for central collisions and changes to negative sign for peripheral collisions with increasing rapidity. for pions   it is quite constant in rapidity for mid - center collisions and peaks near midrapeidity for peripheral colliders.
we propose a general numerical approach to study the invasion capacity of a mutant population and to determine the evolutionary singular strategies when the competitive exclusion principle holds.   the method is applied to a mass - structured chemostat model where mutations affect the division parameters, namely the mean proportion of the smallest daughter cell during the division and/or the minimal mass required for bacterial division. in the deterministic case, the invasion fitness of the mutant population is defined as the principal eigenvalue of the growth - fragmentation - death operator in the polynomial case, and in the stochastic case as the survival probability of the mutation in the population. by comparing the results of the simulations with those of the simulation of the evolution of the one - dimensional trait representing the mean portion of the largest daughter cell in the division mechanism, we show that the optimal strategy for the population to adopt in terms of mass division is the cytokinesis strategy.
advanced gravitational wave detectors are being constructed with the goal of increasing the sensitivity of the detector by tenfold over the first generation of detectors.   the projected sensitivity of these detectors will be limited by the thermal noise of the test masses themselves, which is expected to be the dominant contribution to the total thermal noise in the detector output. a way to reduce the effects of the coating brownian thermal noise is to use a larger beam spot on the test mass surfaces, since a large beam spot averages more effectively over the random motions of the surface. here   we discuss the research performed by the birmingham group towards evaluating the feasibility of using higher - order lg mode technology for implementation in detectors of the advanced generation and beyond to reduce this limiting brownian heat noise limit.
macroscopic quantumness is a fundamental question in quantum physics and optics.   it is not sufficient for a state to be either macroscopic or quantum, but it should be quantum - mechanically macroscopy or quantum - mechanical macroscopicity.. we want to know whether and/or how much a physical system is _ both _ macroScopic _ and  quantum., we would like to pose three requirements for a desirable measure of macroscopia quantumness.  the first requirement is that the measure should be applicable to a wide range of states, not limited to a specific type of states. on the second requirement,   the measure must be able to quantify the degree of a genuine superposition against a classical mixture, together with its effective size factor. on an third requirement, if a state is given, the degree should be unambiguously determined. in view of these points  , we shall review in chronological order such measures proposed to quantify Macroscopic Quantum Superpositions.
a new measurement of the parity - non - conserving ( pnc ) asymmetry in radiative neutron - proton capture at low energy is in preparation at lansce @xcite, intending to improve upon a previous one.   this one is expected to be dominated by the pnc pion - exchange force and its measurement should therefore provide unique information on the coupling, @xmath2nn, which it strongly depends on. recently, a new calculation based on a different approach, namely an effective field theory, came with a larger value,@xmath7, and furthermore an opposite sign compared to the previous one.this paper aims to compare the recent calculation to earlier ones, which, because they were quite sophisticated, can be used as a benchmark for testing the applicability of the effective field - theory methods to the process under consideration. at the same time, we discuss the points that are sources of discrepancy between calculations. after reminding a few ingredients required for the calculation of the asymmetry of interest here, we show that the expression obtained in the new approach at the leading order identifies to a standard potential based calculation employing zero - range nucleon - nucleon forces. in the third section,   we
the self - oscillation of the torque oscillator ( sto ) has attracted much attention due to its potential uses for a microwave generator and a recording head of a high density hard disk drive.   however, the relation between the current and the oscillation frequency of the sto still remains unclear. in this paper, we derive the theoretical formula of the relation from the energy balance between the work done by the spin torque and the energy dissipation due to the damping of the field - like torque on the electrostatic interactions between the magnetization of the perpendicularly magnetized free layer and the in - plane magnetized pinned layer using the landau - lifshitz - gilbert ( llg ) equation as a starting point. with increasing the current, the oscillations of the two layers decrease monotonically, and the shift direction of the frequency, high or low, is determined by the sign of the force generated by the field-like torque.
the generation of controlled quantum correlations distributed over large number of subsystems is an important resource in quantum information and computation protocols.   the practical realization of these protocols using multiparty quantum systems is severely challenged due to decoherence caused by the interaction of the system with the environment, which creates superfluous quantum correlations between the system and the environment leading to information being scattered in the intractable hilbert space of the environment. a generalization of the weak measurement reversal protocol based on the reversibility of weak measurement to protect the robustness of multipartite quantum correlations under local decoherent conditions is proposed. here  , we study the effects of local amplitude damping channel ( ladc ) on the generalized greenberger - horne - zeilinger ( gghz ) state of a one - way quantum computing system using the mayer - wallach measure for global entanglement and the logarithmic negativity for single qubit quantum correlations as well as the reversal weak measurement against ladc. from a theoretical point of view, the characterization of the mixed state quantum correlations in the initial state is irrelevant because each subsystem of the state interacts independently with the surrounding environment ; i.e., each subsystem
we investigate the dynamical and thermal evolution of an infinitely long cylinder to model a filament formed in the post shock cooled sheet and estimate the minimum mass of the fragment of the cylinder.   the model is based on the virial equation for a cylinder and the time evolution of the cloud temperature, the cooling by the radiation and the reduction of the temperature by the recombination of hydrogen molecules. when the gas pressure is comparable to the gravitational force, the fragmentation of the cooled sheet into filaments occurs more easily than into spherical clouds. as the virile temperature of a filament is essentially constant, its evolution is much different from that of a spherical cloud whose virial temperature increases as the cloud contracts.
we report the photometry of supernova 2002ic   @xcite, a type  ia supernova that shows both silicon absorption and hydrogen emission in its spectra.   this is the first case for which there is unambiguous evidence of the existence of circumstellar matter around a supernova ( sn ) and is therefore of great importance to the understanding of the progenitor systems and explosion mechanisms of type  - collapse supernovae.
the magnetic dipole moments of neutron stars are observed to decrease with accreted mass, @xmath5.   several theoretical mechanisms have been proposed to explain this trend, including accelerated ohmic decay, fluxoid - vortex interactions, and magnetic screening or burial. in the latter mechanism, @xcite ( hereafter pm04 ) calculated a sequence of two - dimensional, hydromagnetic ( grad - shafranov ) equilibria describing the structure of the magnetically confined mountain of material accreting at the magnetic poles of a neutron star. in this paper  , we extend the @x Math6 relationship to @x math12 by loading equilibrian solutions into zeus-3d, a multi - purpose time - dependent, ideal - magnetohydrodynamic code for astrophysical fluid dynamics, and adding extra mass quasistatically through the outer boundary of the simulation volume. using a set of test cases relevant to the problem of magnetic burial, we systematically explore the stability of the hydromneticrosymmetrization of these equilibriums in terms of linear and nonlinear perturbations. from the results of pm04, we propose a solution method for solving the problem
the ceres data for the measurement of dilepton production in medium modifications of hadrons from nucleon - nucleus collisions at 200 gev per nucleon by the ceres collaboration at the cern - sps show a considerable enhancement over the expected yield from hadronic decays.   this enhancement is due to pion annihilation, which is unique to heavy - ion collisions since they create a dense system of pions which then can annihilate. as compared with the central points of the previous ceres measurement for @xmath7, the results of the new work by li et al. on the dilepton spectra of the @x Math5-meson in medium changes of hadron collision are consistent with the hadronic calculations.
we present a model of a magneto - hydrostatic and spectropolarimetrically accurate sunspot.   the model is based on the sunspot - like model of @xcite, and is adjusted to provide a more accurate replication of photospheric sunspot properties taken from semi - empirical models, while still maintaining a smooth transition of physical properties between the near - surface and the interior layers. in this way, the model can be used to study the effects of helioseismic inversions of solar magnetic fields on the propagation and mode conversion of magnetoacoustic waves in the solar atmosphere at the alfvn / acoustic equipartition level. using a combination of spectral line synthesis codes and radiative diagnostics tools, we show that the speed and sound speed perturbations caused by the process of magnetohydrodynamic wave mode conversion can be reproduced in a non - linear manner in the presence of a well - defined solar magnetic field concentration, and that the effect of convective stabilisation on the eigenmodes of solar models is negligible.
the discovery of the @xmath0 gev scalar particle @xcite with the properties of the standard model higgs boson together with the so far negative results for searches of supersymmetry are pointing to a possibility of a very different model building paradigm based on a minimally extended standard model with manifest classical scale invariance. in this paper   we will present the first, to the best of our knowledge, realisation of a slow - roll cosmological inflation mechanism in a classically scale - invariant bsm theory.
the bond fluctuation model ( bfm ) is a coarse - grained lattice model for studying the conformational properties of linear polymer chains in dilute solutions under good solvent conditions.   the bfm is used to simulate the behavior of the bottle - brush polymer consisting of hydroxyethyl methacrylate ( pmma ) as the backbone polymer and flexible poly(n - butyl acrylate ) ( pnba ) as side chains in a good solvent ( toluene ) using monte carlo and molecular dynamics simulations, and the results are compared with those of the off - lattice bead - spring model based on the standard simple cubic lattice models ( sclm ) where only the discrete angles @xmath4 and@xmath5 are allowed. by varying the backbone length and side chain length of the bottles brush polymer, a direct comparison of the simulation results with the experimental data   is also possible.
the coherence property of bose - einstein condensates ( becs ) has been investigated intensively after the experimental realizations of becs in dilute gases @xcite.   several theories have been proposed to interpret the observed high - contrast fringes for two initially independent condensate. in the present work,   we calculate the density expectation value by including carefully the interatomic interaction. quite different from the simple derivation in other theories, it is found that upon expansion, there is a nonzero interference term in the density expectance value when the inter atomic interaction and exchange symmetry of identical bosons are both taken into account. to exclude any possible error in the cumbersome derivations, we Calculate the density expectationsance value and evolution equations by both the first- and second - quantization methods, and the same results are obtained. after removing the double - well potential trapping the two initial independentcondensates, we give the theoretical result of the density Expectance Value which agrees with the experimental results of the interference patterns observed in@xcite.graphical abstract
we present a numerical study of the polarization dependency of the transmission for rectangular holes arrays made of subwavelength cylindrical holes in a thin metallic layer deposited on glass, a dielectric substrate.   the results are based on a coupled modes method associated with the use of the scattering matrix ( * s * matrix ) formalism. taking into account the periodicity of the device, the permittivity is first described by a fourier series and the electromagnetic field is described by bloch s waves which can also be described by fourier Series. in this context  , maxwell s equations take the form of a matricial first order differential equation along the @xmath0 axis perpendicular to the@xmath1 and @x math2 axies where the permitting is periodic. using the x - ray scattering matrix formalism, we show that the transmission depends on the polarization of the incident light at normal incidence but not on the wavelength of the transmitted light. moreover, for a square grating made of circular holes, the polarization dependent transmission is only observed for the main axies of the grating which are inverted during the propagation of the excitation whereas for a Square gratingmade of rectangular holes
biometric authentication systems allow authenticating individuals by comparing a query provided by the claimant to its biometric reference.   semi - supervised template update is an active field of research mainly studied for morphological modalities, whereas they are less subject to variabilities than the behavioral ones. in this paper  , we propose a new hybrid template update system that uses fusion as in co - update systems, whereas it is a self - update system and the user s biometrics are represented by several biometric sub - references evolving in parallel by using different template update methods.we propose two metrics in order to evaluate the efficiency of template update systems over several sessions ; ( 1 ) we evaluate the method with a dataset providing more samples per user than most studies of the state of the art ; ( 2 ) we show that the method performs better than the classic self -update system from the literature.
the transmission of light through optical fibers is ubiquitous in optics.   however, fibers are easily deformed, and vibrations and temperature changes cause an unwanted modulation of the optical path length, thus phase modulating the transmitted signal. for example, even for fibers as short as a few meters under quiet laboratory conditions, the phase fluctuations easily exceed @xmath3 on a timescale of seconds. when using fibers to transmit light between laboratories or different buildings, the corresponding broadening of the spectrum reaches several khz, which may appear negligible against the frequency of optical radiation ; however, the tremendous progress in optical frequency stabilization has lead to lasers with a linewidth of one hz and below @xcite that are used in optical clocks and tests of fundamental laws of physics. here  , we present a method to remove the unwanted effects of the path length fluctuations from a 3.5 km fiber optics link between laboratories in boulder, colorado and the max - planck institute for quantum optics in germany. by using an acousto - optic modulator ( aom ) to pre - modulate the phase of the light incident to the fiber with the negative image of the fiber noise,   the amplitude of the beat
we investigate two combinatorial models of optimization problems that have the unusual feature that although they have the same static properties determined by the list of energy levels, the energy landscape is different since the notion of which states are close to each other is not the same.   we perform dynamical simulations of relaxation after a deep quench to explore the energy landscapes for each of the models following a similar strategy to that used to investigate other computer science problems such as satisfiability and graph colouring. using the problem of sorting as a motivation, we consider two different energy functions that compute the degree of sortedness in different ways : one is similar to the traveling salesman problem ( tsp ) and measures the cost in terms of the length of a path, the other assumes knowledge of the sorted state and computes the distance from that state in a direct manner. by investigating these two models we discover that the spectrum of energies is identical but the hamiltonians are different, and the energy each hamiltonian assigns to a given state is not exactly the same.we investigate the local dynamics after a quench and show how it displays very different behavior for each model : in one case the sorted ground state is eventually found, in the other case
lattice qcd thermodynamics is important for various research areas such as heavy ion phenomenology, cosmology and astrophysics.   it is mandatory to improve estimates on some basic thermodynamic quantities which have been obtained in previous lattice calculations. here   we present several thermodynamics quantities, which are susceptibilities of the light and strange quark chiral condensate, the polyakov loop susceptibility, the static quark potential, the spatial string tension, and the sommer scale. by using the p4fat3 quark action @xcite, we find almost no mass and cutoff dependence in the potential scaled by @xmath15 and 6.2 on lattices with a pion mass of about 150 mev and a kaon mass of approximately 500 mev. since the strength of the transition decreases with increasing quark masses, this is reflected in the decreasing peak height of the chiral susceptibilities, we calculate these susceptibilities on latticing with aspect ratios of 0.7 and 4.1. also, we show that the deconfinement phase transition is not a true phase transition in the thermodynamic sense but a rapid crossover.
iron is the sixth most abundant element in the universe, and the most abundant refractory element.   it is observed to be highly depleted in both interstellar and circumstellar environments, and must therefore predominantly exist in an unknown solid form. here   we show that metallic iron grains of giant stars in globular clusters ( @xcite ) produce featureless infrared emission which can be difficult to differentiate from other dust species, particularly amorphous carbon dust. using a sample of 35 highly - evolved, ( strongly-)pulsating stars with features of oxygen - rich chemistry, we construct the photometric fluxes of these stars at the pulsation phase of their infrared spectrograph ( irs ) spectrum for ~8 @xmath0 m, which are not caused by commonly - assumed dust species ( silicates, alumina ) under normal conditions of temperature and grain size. among these,   only 25 of 34 stars have a positive colour, which implies a flux excess at 8 @x Math0 m which can not be caused by common dust species such as silicates or alumina. this excess flux at long wavelengths   is confirmed by comparison to marcs photospheric model spectra of @xc
in a recent paper @xcite, we have proposed a new approach to the evaluation of lattice tadpole integrals in qcd with wilson or staggered fermions.   the method of asymptotic expansions can be used to expand lattice loop integrals around the continuum limit, which is the limit in which the inverse lattice spacing becomes much larger than external momenta and masses. in a second step,   integration - by - parts relations are used to express all lattice totipot integrals through a few master integrals. in this paper  , we discuss the application of the above method to the case of quantum quarks with staggered fermanions.
many classification algorithms are based on * * boosting**@xcite, which is regarded one of most significant breakthroughs in machine learning.   this study proposes * abc*-boost ( * * a**daptive * * b**ase * * c**lass boost ) for multi - class classification. since mart is known to be a successful boosting algorithm, much of our work is devoted to the empirical comparisons of abc - mart with mart. using publicly available data sets from the uci repository, we show that abc-mart could considerably improve mart.. also, abc--mart reduces both the training and testing time by @xmath11, which may be quite beneficial when the training data set is small.
in @xcite, the computational complexity of a sliding block puzzle,'generalized rush hour ', played on an arbitrarily large @xmath0 by@xmath1 board, is studied.   the puzzle is one of the simplest kind of motion planning problems, involving moving rectangular pieces around inside a bigger rectangle with the goal of moving a specific piece to a specific target location. in this paper  , i introduce a new formulation of the gate design problem, which combines the formal rigor of the graph formulation with the concreteness of the circuit formulation. here   i show that the `` in'or'out'state of a gate s output is not uniquely determined by the state of its inputs, but can be constrained by the combined states of its ` ports ', which are considered as nodes with labeled half - edges and wires connected by gates and wires. for example, if two adjacent blocks are of constant size, each port can be either'in'( defined as being in the same state as both the input and output of the other ) or '' out'( described as being non - in'), and each wire can be considered as having an inactive wire. using this formulation,
abstractheavy - ion reactions around the coulomb barrier often show a behavior that can not be accounted for by a simple potential model.   one of the well known examples is a large enhancement of sub - barrier fusion cross sections due to the couplings between the relative motion of the projectile and target nuclei and their internal degrees of freedom, such as surface vibrations for spherical nuclei, or rotational motion for nuclei possessing a static, intrinsic deformation. in order to analyze experimental data for these low - energy reactions,   the coupled - channels method has been employed as a standard approach. here  , we use a random - matrix model for the non - collective excitations of the zr isotopes in the @xmath2ne +@xmath4zr system, which are strongly coupled to the ground state, to investigate the role of these excitations in the structure of the fusion and quasi - elastic barrier distributions.the results show that the calculated barrier distributions are almost identical for the two systems, even when the collective excitation of the colliding nuclei is taken into account. however, the experimentally measured barrier distributions for both systems are found to be different in an important respect.
the presence of many degrees of freedom in string theory has, over the years, galvanized the emergence of a variety of models implementing assisted inflation, a certain type of multi - field inflation whereby the presence of multiple fields increases the hubble friction, allowing for steeper potentials to still drive slow roll inflation.   one shortcoming of these models, however, is the need for fine tuning initial conditions for particular potentials, especially in the absence of an attractor solution. here  , we investigate a, so far largely ignored, discriminating property of such models, namely the possibility that fields decay during inflation. by " decay "   we mean that individual fields suddenly become obsolete, while their energy is converted into other forms, such as radiation or energy - momentum conservation ( e.g. x - ray ). using a simple separable potential, we show that this can be achieved by introducing a continuous decay rate of several fields in any given hubble time and by introducing an additional component of the total energy momentum tensor that takes over the energy of the disappearing fields. with this in mind, we find that it is possible to discriminate a given multidimensional model from its single field analog by measuring the
we study the influence of thermal excitations on collective oscillations of the condensate in the collisionless regime using the gross - pitaevskii equation and perturbation theory.   we consider spherically symmetric traps, since in this case the spectrum of excitations is easily calculated, avoiding the use of further approximations.    we explore, in particular, the properties of monopole oscillations by studying the temperature - induced resonances that occur in thecondensate when an external perturbative of the trapping frequency is applied and, also, the landau damping associated with the interaction with thermally excited states.
quantum tunneling is one of the major aspects of quantum mechanics that sets it apart from classical mechanics. in this article, we study quantum tunneling as part of quantum adiabatic optimization ( qao ) in the simplest possible situation : tunneling in position - space through a one - dimensional barrier.   we find that an asymptotic analysis of qaospectral gaps for @xmath2, which give bounds on the adi abatic run time, fail to accurately describe the behavior of the tunneling for moderately large@xmath0. despite the simple nature of the barrier tunneling problem, we show that @x Math4 is needed to ensure that asymptic expressions accurately describe behavior, to the point where polynomial and exponential run time scaling can be confused for lower @x math0. given the current and near - term sizes of quantum computer implementations @xcite, this failure of asymaptotics casts doubt on the efficacy of using asymiptotics to analyze the output of these systems or to predict their capabilities.
the globular cluster m5 is one of the richest collections of rr lyrae stars in the galaxy.   it is also home to one of only two known dwarf novae in galactic globular clusters. until now,   not a single blue straggler candidate has been identified in m5. as part of our program to study the distributions of blue stragglers and variable stars in globular cores, we have now imaged ngc 5904 = m5 using a series of twenty - two 600-second exposures of m5 s central ( r@xmath0 ) region, spanning 11.5 hours, obtained on march 21, 1993 with the _ planetary camera _ ( pc ) aboard the _ hubble space telescope _ ( hst ) before the repair mission. here   we describe the observations and reductions ; the cmd of the core of m 5 is presented in section 3.    the variable stars we find are described in section 4 while our results are summarized in section 5.
the binary pulsar psr  b1259@xmath063  is in a highly eccentric ( @xmath2 ), 3.5-yr orbit around a 10th magnitude b2e star, ss 2883, with a circumstellar disk.   two periastron passages of the system have been observed in detail, the first on 1994 jan 9 and the second on 1997 may 29. during the first passage,   transient, unpulsed radio emission was detected at frequencies between 0.84 and 8.4  ghz, with rapid variations superimposed on an overall increase in the flux density at all frequencies. here   we propose a simple model for the radio light curves which reproduces the main features of the data and identifies the essential physics of the pulsar  disk encounter as a strongly time - dependent, magnetized, hydrodynamical interaction forming a cometary pulsar wind nebula surrounded by a shock front where acceleration of electrons in the be - star disk is followed by a combination of adiabatic, synchrotron and inverse compton cooling.
the volume and variety of " big data " pose serious problems to traditional database systems.   data are generated at an unprecedented volume by scientific instruments, or by humans connected around - the - clock to mobile platforms such as facebook and twitter. in order to process these data,   it is necessary to load them into a relational database management system ( rdbms ) using a schema - driven process. here  , we present a web - based loading solution for semi - structured data types, e.g., key - value and js data, which can be directly queried from sql using a well - defined interface without the need for a relational schema. with this approach, we show that the loading process replicates multi - terabytes of data three times  in ascii csv and internal database representation  and it can take several days  if not weeks  to process the data.
we have undertaken the preliminary steps in a program that aims to utilize cosmic rays as an experimental probe of theoretical generalizations of the standard model.   we have in mind possible applications of cosmic rays for the study of supersymmetry, particularly in the context of top - down models of ultra   high  energy cosmic rays ( uhecr ). in these models   the primary cosmic rays originate from the decay of a metastable superheavy particle which decay at rest, fragmenting into ordinary hadrons and photons. in this paper   it is shown that the dynamics of these decays can be modelled using standard qcd tools on which we elaborate below.
we investigate the formation of kilometer - sized planetesimals at 1 au by the gravitational instability of the dust layer in a self - gravitating collisional particle disk using @xmath0-body simulation.   we use the hill equations to calculate the dynamics of the particles in gas and the euler equation to estimate the time scales of the collisions between the dust aggregates and the gas. for the first stage of the formation process,   the growth of the aggregates from centimeter size to kilometer size is faster than the mass predicted by the linear perturbation theory. on the other hand, the accretion of planetesimal aggregates is slower than the rate of growth predicted by both the linear and the alternative model of collisions ( ~1.5 km / s ). when the two - dimensional numerical simulation is performed with a local - shearing box, it is found that the formation timescale of the planetesima formation process is on the order of the keplerian time, thus avoiding the migration of meter - sized aggregates.
solar prominences are often found inside coronal cavities, which are tunnel - like elliptical dark regions @xcite at the solar limb, with up to 40 % density depletion around the Prominences.   the magnetic structure hosting a prominence and its cavity is believed to be a helical magnetic flux rope confined by overlying magnetic loops, which is consistent with observed spinning plasma motions and linear polarization signatures. here   we report a set of 3d models that for the first time ever demonstrate continuous formation of prominence condensations in a coronal cavity, achieving a balanced chromosphere - corona plasma cycle characterized by vertical flows in thin prominence threads. using isothermal numerical magnetohydrodynamic simulations, we show that the formation of a 2d and 3d flux rope driven by footpoint motions and flux cancellation can be simulated in a three - dimensional ( 3d ) space with a finite beta corona of 1 mk constant temperature and an elongated sheared magnetic field. during the process of prominence formation and mass cycling,   hot plasma flows from the chromosphere to the corona continuously flow through the center of the prominence threads, whereas the cold plasma flows into the cavity from the bottom of the
ultra - compact x - ray binaries ( ucxbs ) are rare systems in which a low - mass companion star transfers material onto a neutron star or black hole.   the current known sample consists of 27 systems, 8 with known periods, 4 with tentative periods and 15 candidate systems. here   we present the results of a long term campaign to find a stable period in 4u0614 + 091 , which would most likely represent the orbital period. using optical photometric observations from the 80 cm iac80 telescope ( izana, spain ), the 2.5 m nordic optical telescope ( not ) and the 1.5 telescope at san pedro martin ( spm ; mexico ), we show that the observed binary is a ucxb with an orbital period of about 20 mins.    the system is also associated with a bright burst of x - rays, which is consistent with a low luminosity accretion disk.
the twin paradox is one of the most discussed consequences of the theory of relativity.   it is based on the fact that time scales change with distance, when observed from different reference systems, which are in relative motion with respect to each other, with the additional condition that the speed of light is independent of the reference system.    in this paper we show that this interpretation of relativity is incorrect and that the twin paradox does not exist at all. by using the lorentz transformation   we will show up, where the mathematical flaws come in, and how they can be corrected. also, we will consider some real effects of relativity, especially with regard to the consequences of Lorentz invariance in accelerated systems.
we derive a theory of fluid dynamics based on the finsler spacetime framework.   this model is a generalization of the kinetic theory of fluids which provides a unified description of a lorentzian causality, observers and gravity. in this model   the density function becomes a function on observer space,@xcite which is the space of physically allowed four - velocities. from this space   we construct an observer space and discuss its geometric structure.we apply this formalism to two physically motivated examples : a collisionless dust fluid and a fluid with cosmological symmetry.
the source rx j0720.4 - 3125 is an unidentified soft x - ray source seen by the einstein ipc, exosat le ( low energy detector ), and, most recently, by the rosat pspc ( position sensitive proportional counter ) and hri ( high resolution imager ).   we argue that this source is an isolated neutron star accreting from its surroundings. unlike the two other candidate old neutron stars, this source shows evidence for an 8.39 s rotation period  longer than in any known radio or @xmath15-ray pulsar. from this  , we suggest that the magnetic field on this star must decay on timescales @x Math4 y if it was born spinning rapidly. a measurement of the period derivative@xmath10 would help test this model.
we study the properties of perturbative excitations on a family of tachyonic vacua constructed at infinite vacuum expectation value of the tachyon with a runaway potential and born - infeld type u(1 ) gauge field.   we find that the most general homogeneous configuration of the effective field theory for the system of unstable d3-brane is the time - dependent rolling tachlon with constant electric and magnetic fields. under a reasonable shape of the runaway tach Lyon potential  , we find an exact form of the classical rolling taching solution, which may make further study more tractable in the scheme of effective field theories.
the weibel instability is a magnetic instability that gives rise to the aperiodic growth of magnetowaves with a wavevector that is parallel to the cool direction @xcite and with wavelengths that are comparable to an electron skin depth.   it has been previously unclear how a strong thermal anisotropy could form and survive over spatial scales that exceed the wavelength of the modes, which are destabilized by the weibel stability in its original form. here   we show that this process can be important for energetic astrophysical plasma. using particle - in - cell ( pic ) simulations, we find that the tawi can be suppressed if a shock is limiting the extent of the rarefaction wave to a length that is shorter than the duration of its modes.see research article .
the anisotropic hydrodynamics of magnetized strange quark matter in compact stars is studied.   the two bulk viscosities are calculated and their implications for the r - mode instability in rotating quark stars are discussed.
we propose two new classes of orthogonal body  fitting coordinate systems that are well  suited to the axisymmetric geometry of two colliding black holes, and that appear promising to improve upon current calculations.   the new coordinates remove the singular saddle point from its obtrusive position at the origin and thus offer a potentially cleaner and more stable method of solution.
in the context of canonical quantum gravity, the boundary hamiltonian ( @xmath1 ) is the surface observable of the gravitational field.   it is well - defined on the hilbert space induced from the expansion of the state space by the gravitational action in the real new variables @xcite. here  , we quantitatively quantify this surface observable using the method of functional differentiability and show that it reduces to the quasilocal energy of brown and york@xcite, to the arnowitt - deser - misner ( adm ) energy in asymptopia, and to the misner - sharp mass in spherical symmetry ( @xaite ).    the results are compared with those of two previously published quantizations of the same surface observable.
we consider the behavior of a spherical hole in an infinite universe with a uniform distribution of mass.   we show that there is an outward - directed gravitational force acting away from the center of the spherical hole, and we develop a formula for this force. using the newtonian differential equations, we discover the expansionary behavior of the hole and develop a new formul to be used later. finally, we give a new cosmological model for an expanding universe in which holes are the dominant feature.
we report the magnetic behavior of a new cobalt^ii^@xmath0(oh)@x Math1(c@x maths2@x math3h@x mathematics2@Xmath4o@xMath0)@xcite hybrid framework of formula co^ii+^ hydroxy - sebacate framework with a single - chain magnet ( scm ) at @xmath8 k. the structure and macroscopic magnetic properties of the system are investigated by neutron scattering techniques.   the results show that the system exhibits a very low - dimensional long - range order ( lro ) in the ordered phase, which is due to the combination of a large magnetic anisotropy with ferromagnetic interactions between the organic moiety and the metal - organic framework components. for the first time, we show that these interactions are not only through - bond interactions but also via non - classical dipolar interactions between spin layers.    the obtained results are in good agreement with the predictions of r. j. glauber in 1963.
decoherence may occur everywhere and cause great trouble in implementing quantum tasks.   this is due to the unavoidable coupling between any realistic quantum system and its environment, which may lead to fast destruction of quantum superposition. here  , we propose a scheme to characterize the non - markovian dynamics of a qubit coupled to a thermal ising spin bath and introduce an ancilla. by studying the dynamics of non - classicality of the qubit system,   it is shown that revivals of the negativity of quantumnes can be treated as a signature of non-markovianities. moreover, we investigate the influences of bath criticality, bath temperature and bath size on the non-marksovianity using a measure of the nonclassicality based on the negative attitude of the quantumness and find that the non--markovia converges to zero very sensitively at the critical point as the bath size is enlarged. besides, it is also interesting to explore the behaviour of the positivity of quantumness to compare with that of other discord - like quantifiers where the phenomenon of sudden change or sudden transition may occur.
the field of photometric surveys has now been booming for one decade and continues to develop.   the complexity of the analysis is coming from various reasons : the large number of sources, the diverse intrinsic natures of the observed stars ( there is a real zoo of variable stars ), the complex of the flux or magnitude data ( because perfect data do not exist, there are outliers, the number of measurements may vary from one star to an other for the same survey, the noise depends on the magnitude ), and the irregularity of the time sampling. in this paper  , we will take the gaia survey as an example and see what types of questions are being tackled for the preparation of some aspects of the data analysis.
we consider an abelian _ gauged o(3 ) sigma model with a nonminimal coupling, where we have included maxwell and chern - simons terms.   self - dual soliton solutions are obtained for this model at a critical value for the nonMinimal coupling constant. in particular, we give the asymptotic behaviour of the topological and the nontopological solitons and present the numerically calculated soliton profiles for both cases.
hot molecular cores ( hmcs ) are believed to represent the earliest stages of massive stellar birth, however there are very few observations of these objects to date.   i present here sub - arcsecond 18 @xmath0 images of the sites of three hot molecular cores that are located in massive star forming regions near ultracompact hii ( uc hii ) regions. all three sites contain water masers that are isolated from centimeter radio emission sources and all three have been found to contain ammonia emission coincident with the water maser locations, as observed through high - resolution molecular line imaging. since the mid - infrared is a good wavelength regime to try to detect these types of sources, the observations were performed at the gemini north and keck ii telescopes using the university of florida mid-infrared imager and spectrometer oscir. during the observations point - spread function stars   were observed, yielding an estimate of the effective resolution of the observations of 041. at thegemini north 8-m telescope  , there were no detections of mid - Infra - red sources at the locations of 2 of the 3 hot molecular core sites. while at the
the symmetry energy of the nuclear equation of state, which is the difference in energy between the pure neutron matter and the symmetric nuclear matter, shows very different behavior above and below normal nuclear density.   various interactions used in  ab initio " microscopic calculations predict different forms of the density dependence of the symmetry energy, and hence their extrapolation to the structure of neutron - rich nuclei, as well as to compact stellar objects such as the neutron stars. by studying the isotopic yield distribution of the fragment isotopic yields in two different intermediate energy heavy ion collision reactions, r@xmath7(@x Math8,@x maths9 ) = y@x math10(@ xmath8, @xmath9)/y@xMath11(@Xmath8,@x mathematics9 ), we have shown that the ratio of the fragments isotope yields in these reactions obey an exponential dependence on the neutron number and the proton number of the isotopes ; an observation known as isoscaling @xcite. using a combination of statistical and dynamical multifragmentation models,   we show that this dependence is directly related to the scaling parameter @xmac14, which increases monotonically with
we present the statistics of the monthly variation of the wind velocity at 200@xmath0 mb for the mexican sites sierra negra and san pedro mrtir.   the data were obtained from the noaa ( national oceanic and atmospheric administration ) global gridded upper air database ( gguas ), which contains data from 35 balloon flights taken between february 2000 and november 2003 in the state of puebla, mexico. using a differential image motion monitor, we obtained the average velocity of the turbulance v@x math3, defined as a function of refractive index structure constant @xmath1 and turbulence velocity @x Math2, during 127 nights at 200=0.5  km above sea level. to evaluate the suitability of the sites for adaptive optics, we compared the results with those obtained for the following sites : mauna kea, hawaii, paranal and la silla in chile, gamsberg in namibia and maidanak in uzbekistan.    the results show that the wind speed at 200#mb is a very important parameter for the selection of sites for the new generation telescopes
the early - type magnetic chemically peculiar stars, often referred to as ap / bp stars, are main sequence objects found over the entire spectral type range from early b to early f, but most commonly around a0.   these stars are not constrained to a particular evolutionary stage and are found both near the zams in young open clusters and among the stars at the end of the hydrogen core burning phase @xcite.the presence of a super - equipartition magnetic field, which usually has a topology close to an oblique dipole, breaks the spherical symmetry of the diffusive segregation of chemical elements, leading to the formation of spots and rings of enhanced element abundance on the surface of ap stars. here   i review more recent advanced studies of the magnetic field and spots on ap stars, which have the ambition of developing much more realistic and detailed 3-d models of the chemical element distributions, atmospheric structure, and magnetic field topology.
the hydration of neat portland cement ( tricalcium silicate ) is a well - known process that takes place in the presence of water.   the process of cement dissolution, ion diffusion, and hydrate precipitation is usually referred to as'cement hydration '. here   we propose on the basis of nmr spectroscopic measurements an empirical global reaction rate law for thehydration of cement pastes for initial water to cement weight ratios @xmath25. the observed values for the kinetics exponents can be understood  in parts  by classical solid  state transformation theory.
the friedel oscillation ( fo ), first predicted by friedel   @xcite and thus named friedel - friedel phenomenon, is a unique consequence of the sharp fermi surfaces of metals. in doped graphene and other two - dimensional dirac materials,   the long - range fo is determined by the electron s wave functions around the ferm i surface.   however, to the best of our knowledge, there has been little or none investigation regarding the fo in the case when fermis level is close to or at the saddle point. in this paper  , we study the fo when fermani level is near the saddle points in the twisted graphene bilayer ( tgb ) and the topological crystalline insulator ( tci ). using the band structures obtained in simple models, we find that the fo is more pronounced in tgb than in tci. for tgb, the lindhard response function ( * q *, ) = f (*k, * k+q), with form factor @xmath12 associated with the overlap between the two states connected by the momentum transfer @x Math13 shows a singularity near the
we present two novel methods to extract the e1/e2 ratio from electromagnetic dissociation ( emd ) experiments.   the first method is based on the fact that interference terms, between e1 and e2 excitation amplitudes, will produce an asymmetry in the angular or momentum distributions of the breakup fragments. for the second method we use a two - cluster model of the nucleus, but the effects of many - body structure will also be included. using this model   we show that the asymmetry due to e1-e2 interference strongly depends on the final state interaction ( fsi ) between the breakup fragment fragments ; or in other words, on the structure of the continuum up to relatively large energies. at low beam energies,   higher - order dynamical effects will lead to a reduction of these asymmetries.
we present measurements of inter - event durations from digg.com and reddit.com, two online social news aggregators @xcite and from the enron data set, a collection of emails sent by employees of the company enron.   we show that the binning of data ( either by the data - provider or by the researcher ) alters the shape of a lognormal distribution into an apparent power - law, which is consistent with the widely assumed exponential distribution of poissonian Inter - event times in spreading processes or epidemic models.
the infrared - dark cloud g79.3 + 0.3  p1 is a large, cold dust cloud in the cygnus rift region of the galactic plane that can be seen at visible and near - infrared wavelengths by the jcmt scuba satellite @xcite.   it is located close to the sun at an estimated distance of 800  pc from the equator and contains a variety of indicators of star formation, including a herbig - haro jet that appears to be driven by a yso at ra(2000 ) = 20  31  45.5, dec( 2000 ) = + 40  18  44, and a hot star with a mass of about 1.2  109  k. the hii region dr15 lies behind and slightly south of the irdc, between p4 and p5, and its most prominent condensation, which is strongly associated with a warm patch of emission from a deeply embedded hot star, is clearly visible in the msx 8  image. here   we investigate the star - forming activity in the vicinity of this condensation using both the scuba and msx images of the same region. for the first time  ,
we study bell inequality and nonlocality in a two - dimensional heisenberg - ising mixed spin system.   firstly, we consider some expression @xmath3, namely, a function for the state@xmath4, which can be expressed as a bell function. then, we find that for all the states described by a realistic local theory, we can always identify the upper bound @x Math5 for @x math3.. however, for some local states @x maths4, the bell inequality is violated, i.e., it is not possible to characterize the state by any realistic local theoretical theory. on the other hand, for several matrix product states, we found that the two - qubit states do not violate bell inequality but they are entangled. here  , we show that there even exists some kind of quantum correlation, which cannot be characterized by non Locality and entanglement, e.g., quantum phase transitions at finite temperatures.
abstractastrophysical discs are observed to transport angular momentum.   it has been hypothesised that such discs are transporting angular momentum through a turbulent process @xcite. in this letter   we demonstrate how the distribution of a rare gas - phase species ( tracer species ) that is only abundant outside a snow - line ( being destroyed inside ) is strongly dependant on the schmidt number, and that _ alma can be used as a proxy for the strength of the turbulence that results from the transport of dust particles in protoplanetary discs. using a combination of experimental and theoretical data, we show that the sch Schmidt number is a strong determinant of the size of the turbulent diffusion coefficient ( @xmath2 ), with a range of reported values ranging from two orders of magnitude to two order of magnitude depending on the type of turbulence. at the low temperatures and ionization fractions expected in accretion discs,   non - ideal magneto - rotational instability ( mhd ) effects become important, qualitatively changing the nature of the turbidity and its associated transport properties, or rendering it ineffective resulting in'dead - zones '.
the formation of an encounter complex is a first passage problem in the physical transport process required for receptor - ligand binding. in this paper  , we address this situation theoretically by combining methods from hydrodynamics and stochastic dynamics.   we show the situation which is theoretically analyzed in the following : a spherical particle with radius @xmath0 moves with hydrodynamic flow in positive direction above a wall at a height@xmath2 above the wall. in order to solve the corresponding mean first passage time problem,   computer simulations of the appropriate langevin equation are performed. using these results, we find that the interaction between the particle and the wall depends on the position of the receptor and ligand patches on the surface of the wall as well as on the relative density of the surrounding fluid. when the particle is attached to the wall, the probability of forming an encounter complexes is determined by the translational and rotational movement of the cell as determined by external forces, e.g., gravity, thermal diffusion or other external forces. here, we show that the formation of the encounter complex can be solved with the first approach of any pair of receptors and ligands patches smaller than a prescribed
stochastic modeling plays an important role in many areas of science, such as physics, ecology or chemistry.   stochasticity and delay appear together with delay terms in many situations of interest, but the combined effects of these two factors are not completely understood. from the mathematical point of view,   non - markovian processes including delay are difficult to analyze due to their non -Markovian character.. in this work we study some simple, yet general, stochastically birth and death processes including delayed degradation and delay.    we develop tree different approaches to the analytical study of this kind of non - Markovian process, in the general case of stochically distributed delay, including a direct approach, an effective markovians reduction, a master equation approach and a time - reversal invariance assumption. for the first two cases, we consider the simplest possible process, that is, a particle is created at a rate and disappears (  dies " or  degrades " ) a time after being created. by allowing the delay time to be random variables with arbitrary probability density functions, we show that the methods presented here can be applied to systems with first order reactions and without feedback.
the galactic bulge monitoring program carried out by the bepposax satellite in the energy range 2 - 30 kev has led to the discovery of 6 new burst sources and, in addition, found burst emission from 7 already known sources.   the new transient sources show dim x - ray outburst episodes during @xmath01 to a few weeks, with peak fluxes generally below a few 10@xmath4  erg / s at 10  kpc distance. from one of these sources, sax  j1808.4 - 3658 ( @xcite ) a modulation period of 2.5   ms was discovered by _ rxte_ during a second outburst. here   we report results of one of those previously unknown transients showing bursting behaviour, discovered by the wide field cameras experiment on board the wfc in a celestial position 1.2 degrees off the galactic center during spring 1997. using time profiles of the total detector over the entire energy range with a time resolution of 1  s, we analyse the spectral and temporal behaviour of the persistent emission and characterise the burst emission properties to determine the nature of the transient.
computer generated holograms ( cgh ) are a well - known method for electronically recording existing three - dimensional ( 3d ) object information on a hologram, which is captured by a charge coupled device ( ccd ) and complementary metal oxide semiconductor ( cmos ) cameras @xcite.   the computational time required for the diffraction calculation involved in cgh hampers the realization of a practical 3d display using cgh. to achieve real - time 3d reconstruction from holograms in digital holography, we need to calculate diffraction calculations.we have designed and built special - purpose computers for cgh targeting a 3-dimensional display and named holographic reconstruction ( horn ), in order to overcome the computational cost of cgh ; the horn computers were implemented on a field programmable gate array ( fpga ) board, except horn-1 and -2. here  , we describe the design and construction of six horn computers, which can calculate fresnel diffractions on cgh at high speed@xcite using the fast fourier transform ( fft)-holographic reconstruction algorithm. among the six horns,   horn-2 is the most advanced and has the highest computational speed
the recent discovery of a new higgs boson - like particle at the large hadron collider ( lhc ) and the tevatron @xcite has opened up the possibility of probing directly the ( genuine ) invisible branching fraction of the higgs in various channels at the Lhc.   we investigate the extent to which current data constrain invisible decays or undetected decays of this higgs - like state. using global fits from the lh cdf and d0 experiments, we find that the sm expectation is more than @xmath7 away from fits in which : a ) there is some non - sm contribution to the @x Math8 coupling of the high - level higgs ; or b ) the sign of the top quark coupling to the higgens is opposite that of the sm.. since option b is difficult to realize in realistic models, it would seem that new physics contributions to the effective couplings of the higher - level hgbs are preferred.
quantum entanglement has been recognized to play a key role in black hole thermodynamics and the fate of information in the presence of horizons.   some previous studies have shown that the interaction with the gravitational field can produce entanglements between quantum field modes in the background of expanding universe scenarios. in this paper   we analyze the issue of entanglery production in a dynamical gravitational collapse by comparing the behavior of a bosonic and a fermionic quantum field which initially are in the vacuum state and compute their asymptotic time evolution under the gravitational interaction in a stellar collapse. for fermions,   the generation of entanlement due to gravitational collapse is more robust than for bosons ; this robustness is more evident from the peak of the thermal spectrum of hawking radiation towards the ultraviolet when the field modes fall into the collapsing star. however, it is not clear whether these correlations are quantum or non - quantum since they are exclusively due to quantum entanglemens. using the vaidya spacetime, we show that the initial vacuum state in the past does not have any quantum entenlement, and that it evolves to a state that is physically entangled as a consequence
we investigate the effect of substructures on the shape of gravitational arcs in the strong gravitational regime.   the perturbative method is used to estimate the deflection field of a lens with a substructure, and to study the influence of the substructure on the distortion of the image morphology. for large sources, like distant quasars, it is possible to evaluate the contribution of substructure to the Deflection Field by analyzing the image flux obtained using ray - tracing. however, for small sources, such as quasar, microlensing by stars in the lens galaxy may be quite sensitive to microlense by the main deflector, which complicates the analysis. in this paper   we show that the perturbed elliptical lens has a cusp caustic regime, while the sub - substructure can have a sub - critical regime by adding a perturbation field to the ellipse of the deflector. when the perturbing field is located near the critical line, the arc is broken in 3 images, which is typical of a sub- critical regime.
we present a new method for fitting interaction models.   we consider a regression model with pairwise interactions between predictors and outcome variables, and show that it is possible to fit the model without violating strong hierarchy, which is the restriction that only allows an interaction into the model if the corresponding main effects are also in the model.
we present an angle - resolved photoemission spectroscopy study of the normal state of the charge stripe ordered cuprate la@xmath0nd@x Math1sr@x math2cuo@x maths3 ( nd - lsco ), in which charge and spin orders are coupled.   we show that the antinodal spectral weight is suppressed by a single particle gap from charge - density - wave ( cdw ) order in the underdoped regime of nd-lsco, which can be closed by either increasing doping to @xmath7, increasing temperature to ~8  k or moving in momentum towards the zone diagonal. compared to the overdoped side of the phase diagram, a significant suppression of spectral weight   is observed in the non - superconducting regime of this material.    this effect is discussed in terms of quasiparticle decoherence and competing electron orders.
old open clusters with ages greater than the age of the hyades ( @xmath6 600 myr ) represent a minority of about 80 objects among 1200 known open clusters.   we have undertaken a spectroscopic and astrometric program to obtain metallicities, distances and velocities of high quality for several poorly known old open clusters, ngc 2355 being our first target. in this study  , we describe the determination and analysis of proper motions from photographic plates and recent observations at the meridian circle of bordeaux for 24 bright stars around the cluster s center and for two hot fast rotating turnoff stars. for the latter, we developed a new version of the tgmet method which allows us to estimate the atmospheric parameters and the absolute magnitude of the cluster.    we also report the discovery of an unusual giant in ngc2355 which is 2.3 magnitudes brighter than the giant clump for the same temperature. as a result of our study, we show that the cluster has a red - shifted radial velocity of 1.5  km / s and a distance modulus of 0.7  km/s. using the star numbers introduced by kaluzny & m
we have computed the cut - off frequencies for the acoustic potentials of two roap stars, hd24712 and hd128898, for which we have more reliable mass estimates due to the availability of hipparcos parallaxes.   the highest observed frequency is 2280@xmath2hz for the hopf and kurucz models with an age of about 900 myr and a hopf law of 1.63@x Math7, @xmath10 and an age between 7400 and 10000myr. in the case of the latter,   these values are within the range of the predicted values obtained from the literature for the same age model.
stochastic resonance is a key phenomenon in the field of quantum interference devices ( squids ).   it is now well established that the performance of a single stochastic resonator can be enhanced, if it is embedded into an ensemble of other stochastically resonators which are properly coupled. here   we study a simple prototype system of coupled two - state sto chastic resonators under periodic modulation. using a simple next - neighbour interaction  , we show that the response of the coupled resonator to the signal increases as the coupling strength increases. however, if the coupling becomes too strong this response deteriorates again and the signal - to - noise ratio ( snr ) is found to be reduced. by contrast, when the coupling is too weak the snr is maintained at a certain level of noise the same effect is not observed. from a conceptual point of view   the model proposed here can be seen as an extension of the 2-state model developed by mcnamara and wiesenfeld ( @xcite ) to study stoChastic resonance in noisy bistable systems. instead of considering individual two -State elements as in@xcite these elements are now arranged in a chain
in order to provide effective channel models, suitable for the design of innovative devices and for the definition of new standards, it is of fundamental importance to assess, and then be able to reproduce, all the channel properties and the specific features of the different environments.   this is even more true when considering a power line communication ( plc ) network, where different wiring structures and network topologies, as well as line discontinuities and unmatched loads, imply an extreme variability of the channel. in this paper, the most common channel modeling strategies are defined and compared, assessing differences and similarities.the top - down modeling strategy is first described for the in - home single - input multiple - output ( siso ) case, then extended to the multiple - input Multiple Output ( mimo ) context.    both the procedures are validated through numerical results.the results show that the top - up approach is a promising technique to develop simple and effective synthetic channel models based on the transmission line theory, which can be easily and directly modeled via a synthetic channel model that generates amplitudes and phases as correlated complex random variables.
we introduce a general lagrangian framework to study the dissipative properties of two - component systems composed of a high - loss and lossless components which can have gyroscopic properties.   this framework covers any linear lagrangia system provided it has a finite number of degrees of freedom, a nonnegative hamiltonian, and losses accounted by the rayleigh dissipation function ( *???   10.11, 10.12, ( *???* sec. 8, 9, 46 ) ). in order to account for the dissipation of such systems we consider a general dynamical system where the lossy component of the composite material / system is represented as a significant fraction of the entire system. using this framework   we show that it is possible to design a composite system having a useful property at a level comparable to that of its lost component but with significantly reduced losses over a broad frequency range.
the w3 complex is a strong, extended continuum source within our galaxy.   it houses active star formation and can be subdivided into multiple regions for which the nomenclature varies somewhat with the type of observations. in this paper, optical depths and spin temperatures at 408 mhz and 1420 mhz as well as 21 cm spectral line data were obtained at the dominion radio astrophysical observatory s ( drao ) synthesis telescope ( st ) as part of the canadian galactic plane survey ( cgps ) pilot project covering an @xmath7 area of the sky, encompassing all of the w3/w4/w5/hb3 galactic complex. while the absorption near 40  is generally considered to be the main focus of the study, the present paper uses sight - lines towards w3 to probe the interstellar medium between us and this region, evaluating its optical depth and spin temperature, and placing it in a galactic perspective. from these data,   the authors conclude that the observed optical depths are due to the dissociation of atomic hydrogen ( hi ) associated with the compact regions, and that the spin temperatures are related to the radial velocity of the central stars.
in a recent publication @xcite i proposed a new approach to quantum gravity in which networks play an even greater role.   the idea is to turn things around and, instead of starting from the correct infrared ( ir ) geometric variables and using discrete space - time just as a regularization artefact, as in the causal dynamical triangulation approach ( cdt ), to posit purely combinatoric information bits as the fundamental ultraviolet ( uv ) quantum variables of gravity and have these self - organize so that geometry and general relativity emerge. this presupposes the existence of a model having an uv fixed point corresponding to disordered bits and an ir limit in which vertices and edges self - Organize to form a network with the topology of discrete space-time. here   i show that this model is indeed possible.
star clusters are vital laboratories for testing theories of stellar dynamics and stellar evolution.   the large magellanic cloud ( lmc ) contains a sample of rich star clusters of comparable mass to galactic globular clusters but which span the entire age range from less than @xmath2 years ( e.g. r 136 ) to about@xmath3 years ( eg. ngc 2019 ). in this study, we investigate whether dynamical processes could give rise to the observed core radius  age relation in the go7307 hst sample of star clusters in the lmc. using numerical simulations, we show that the observed trends in core radius are not due to population variations in the slope of the initial mass function ( imf ) of the clusters but are due to mass segregation in the cluster population. as a result, the core radii of the young and intermediate - age clusters lie at comparable radii from the lMC centre but differ significantly in other properties such as core radius. by means of simulations,   we find that these differences are caused by the same process of mass segregation : encounters between the clusters lead to a redistribution of energy among the stars, which enhances the heating effect of a population of prim
@xcite is a thin ribbon of graphene which can be terminated by a zigzag or an armchair edge.   the electronic properties of the reczag edge have been studied using the difference equations obtained from a tight - binding hamiltonian on the terminated lattice. in this paper   we propose an alternative approach based on the dirac differential equation, @xcite with edge reconstruction accounted for through a boundary condition and show that a broad class of edge reconstructions can be described by a boundary conditions governed by a single angular parameter @xmath0. these boundaries cause no intervalley scattering and support dispersive edge states for @x Math4.    most importantly, they also allow for a reconstruction of the honeycomb lattice and variations in the hopping amplitudes of the next - nearest - neighbor excitations. at the low - energy limit and sufficiently far from the boundary, excitations with energy @x math12 obey the diracs differential equation and the local density of states can be measured by scanning tunneling microscopy.
the ruderman - kittel - kasuya - yosida ( rkky ) interaction between localized spins and paramagnetic itinerant carriers in a semiconductor spintronic system is studied.   it is shown that the exchange interaction is non - local in space but has a finite range @xmath4 given by the spatial spin distribution around the localization center. for this value the oscillations of the itinerant carrier spin density   are responsible for the magnetic ordering of the system.
masers are systems that amplify light by stimulated emission of radiation.   these systems are uncommon, since they require energy levels to be populated in ways not possible under the conditions of thermodynamic equilibrium ( they require a _ population inversion _ of energy levels ). while particles in thermal equilibrium typically absorb light, systems with population inversions can become shining beacons. here   we look at the applications of stimulated emission theory to astrophysical systems, and identify those conditions to which masers are sensitive.
we present a general formalism for the definition of null weak values ( nwvs ) in quantum mechanics.   we define nwv as a measurement outcome read in a detector when the measured system is subsequently found to be in a specific state, and we show that it is possible to measure nwms with a single quantum degree of freedom ( " system " ) since the detector is classical, and that the signal - to - noise ratio ( snr ) amplification is versus inherent quantum and statistical fluctuations, and not only against external detector noise.
we investigate the interplay of currents and correlations in nonequilibrium steady states in a quantum system using the isotropic transverse xy chain as an example.   we find that, in the presence of an energy current, the exponentially decaying two - spin correlations change into power - law form thus supporting the notion that switching on currents increases correlations. in the case of a magnetization current, however, the results are at variance with those for the transverse ising model since the changes in the correlations due to the introduction of a current are treated exactly ( sec.ii ) while the correlations in the absence of an Energy current are calculated by a combination of analytical and exact numerical methods in sec.iii.
pattern formation is one of the most fascinating and intriguing phenomena in nature.   it takes place in a wide variety of physical, chemical and biological systems and on disparate spatial and temporal scales, for example, convection phenomena in geoscience or in liquid crystals, environmental patterns, or patterns in chemical reactions. here   we identify and analyze a new class of quasi-2d _ anisotropic inhomogeneous _ pattern forming systems. by using the pseudo - spectral method, we find that the wave vector of the patterns lies close to @xmath6 along the preferred direction ( anisotropy ) of the preferred symmetry in the proposed system class. by a modulation we break the translational symmetry along the perpendicular direction in such systems, causing a variation of the pattern s natural wavenumber. in these systems we find a whole family of stable branched patterns, which are stable at identical parameters but have different characteristic wave numbers and include different numbers of branching points. as a consequence, they can be described by universal amplitude equations for the envelope of periodic patterns.
the su  ursae majoris ( su  uma ) systems form a subclass of dwarf novae that also exhibit a related but distinct phenomenon, called superoutburst.   these eruptions are approximately one magnitude brighter than normal outbursts and last as long as a couple of few weeks rather than just a few days. in a previous paper ( murray 1996, hereafter paper i ) we described a two dimensional smoothed particle hydrodynamics ( sph ) code specifically designed for thin disc problems. in this paper   we describe a more thorough numerical investigation of the so called  tidal instability  of accretion discs in close binary systems. using a range of binary mass ratios, disc temperatures, and shear viscosities, we show that the observed eccentricity growth rates and precession rates of the discs in the binary system are consistent with observations and analytical results obtained by lubow ( 1991a, 1992).we go on to demonstrate that tidal instability can not only explain the superhumps seen in su uma systems, but also provide a long - term increase in energy dissipation in the disc that is consistent with the excess luminosity of superoutbursts.
dust torus is a natural reservoir of gas supply to the accretion disc in the central regions of galaxies.   the torus absorbs and scatters uv and optical light and re - emits at infrared ( ir ) bands, altering spectral energy distribution as well as causing anisotropic obscuration. due to its great importance  , the geometry, column density distribution and the composition of dusty torus have been subjects of intensive study in the past thirty years. however, the dust covering factor ( cf ) and its correlations with active galactic nucleus ( agn ) properties, such as the number of active galactic nuclei and the spectrum energy distribution, are still controversial. here   we present a new study of the cf for a large sample of obscured and unobscured agns derived from the sloan digital sky survey ( sdss ) and the herschel mid - infrared survey ( hirsutism ). using the data from both surveys, we show that the cf of the dust torus ranges from @xmath51:1 to ~3:1, which is consistent with the results obtained by @xcite and@xcite from the quasi - steller radio sources. while the average opening
the sloan digital sky survey ( sdss ) has been used to detect the tidal tails of palomar 5 and ngc 5466, as well as the presumed globular cluster stream gd-1.   we now report the discovery of four new stellar streams in the galactic halo using the matched filter technique employed by @xcite, @xmath10 cen,@xmath11 cen or @x Math13.5 cen for the color - magnitude data from the sdss dr5 database. among the new streams are two globular clusters and a possible dwarf galaxy progenitor. while the observed luminosity functions of the stars in the streams are not significantly different from those of the foreground population, we derive a general form for the luminosity function of stars in streams based on the very deep luminescence function of @xoxo4 + 2.0 cen , converted to the sloan system using the empirical transformations of @xcites. over the range of absolute magnitudes considered here, we find that these streams are more likely to be in the center of the halo than previously thought, and that they are most likely to have been formed by
the nonlinear tuning rule for the nonlinear tuned vibration absorber ( nltva ) is proposed to mitigate the vibrations around a nonlinear resonance in wide ranges of motion amplitudes.   the non linear tuning rule is based on a simple nonlinear generalization of den hartog s equal - peak method, which is widely used for designing linear vibration absorbers. using a duffing oscillator as a host system as a model system,   we propose to synthesize the absorber s load - deflection characteristic so that its nonlinear restoring force can be tuned according to the nonlinearly restoring force of the host structure. this synthesis is similar in essence to what was achieved with centrifugal pendulum vibrators in rotating machinery @xcite, because they have a natural frequency that scales with the rate of rotation and can be tunable over a continuous range of rotor speeds. by virtue of their natural frequency, these vibrational waves can be suppressed in a relatively large interval of disturbance amplitudes, e.g., up to a few orders of magnitude more than those of a conventional linear damping mechanism, the nltvas can be used for vibration mitigation of nonlinear primary structures.
entanglement and nonlocality are two manifestations of quantum correlations, both of which play an important role in the field of quantum information.   entanglement is in the heart of quantum teleportation and plays a crucial role in quantum algorithms such as quantum memories and device - independent quantum information protocols.. however, the quantification of these two phenomena in the multipartite case is much less explored.    here, we show that the robustness of the @xmath0-qubit dicke - like state ( a generalization of the w state ) to various types of noises, e.g., noise induced by different types of noise, can be quantified by means of a class of bell inequalities. for each set of settings per party,   the number of tight bell inequalities becomes smaller and smaller with increasing number of parties. from above and from below  , we find that the lower bounds of the mean value of the bell inequalities for the total number of particles to be removed for nonlocal quantum correlations to vanish for any set of@xmath5 settings per site are very close to the limit of @x Math8 for all sets of parties up to @x maths9
quantum walks ( qws ) constitute the quantum analogue of classical random walks and also the quantum version of cellular automata.   they have been intensively investigated, especially in connection with quantum information science. in the present paper   we show that it is possible to apply the thermodynamic laws to the qw dynamics after a measurement process. by studying the asymptotic change of the entanglement entropy  , we obtain the upper and lower bound for the asynchrony of the quasiexperimental entropy between the stationary states.
the central limit theorem ( clt ) for the addition of independent random variables with finite second - order moment, which is at the core of the theory of probabilities and mathematical statistics, was first introduced by abraham de moivre in @xmath11.   it has its origin at the weak law of large numbers of jacob bernoulli ( @xcite ), who used the normal distribution to approximate the functional form of a binomial distribution for a large number of events. in this article, we review the fundamental properties of nonadditive entropy, @x Math15, its optimising distribution ( known as @x maths2-gaussian ), and the @x math2-product, a generalisation of the product@xcite formulated within nonextensive statistical mechanics.. we analyse, both analytically and numerically, the sum of conventional independent random variable and show that, in this case, the attractor in  probability space is the gaussian distribution if random variables have a finite second orders of magnitude, or the stable lvy distribution otherwise.
we investigate the hadronic rescattering effects on observables at the relativistic heavy ion collider ( rhic ) and the large hadron collid at cern using an integrated dynamical approach.   we first revisit the violation of mass ordering of the differential elliptic flow parameter @xmath7 by using a hybrid model in which hydrodynamic description of the quark gluon plasma ( qgp ) fluid is followed by a hadronic cascade model, and show that it is not possible to distinguish photons and dileptons emitted from the qgp from those originating from the all stages of high - energy nuclear collisions when the hydrodynamical stage finishes. since multistrange hadrons have small scattering cross - sections with pions, their distributions reflect the properties of the system mainly at a specific stage deep inside the fireball, unlike other hadrons which come from all stages.
we investigate the exact electronic structure of a few - electron two - dimensional confined quantum dot system that contains a single magnetic ion in the presence of an external magnetic field taking into account a sufficient large number of single - particle orbitals such that numerical   exact " results are obtained.   we explore how sensitive the whole system is to the position of the magnetic ions in the quantum dot and to the existence of a magnetic field and investigate the competition between the following three energies : i ) the interaction of the magnets with the electrons, ii ) the interactions of the magnetically inserted magnetic ion with the magnetic field, and iii ) the influence of the external field on the spin polarization of the @xmath2 electrons in the ground state of the system.the results show that the magnetic ion ferromagnetically couples with the@xmath6 electrons in a region below a critical magnetic field while the magnetization and susceptibility of the electrons above this critical field are strongly affected by the strength of the inter - particle interaction and the location of themagnetic ion at the center of the quantum dots.    the thermodynamic properties as magnetization, susceptibility, and the heat capacity are investigated as function of magnetic fields and temperature.
in some models of ultrarelativistic nucleus - nucleus collisions, the formation of quark - gluon plasma ( qgp ) is assumed to proceed via creation of a strong colour - electric field in the region between the two nuclei receding from each other after the collision, and the subsequent decay of the field by parton - pair production according to the well known nonperturbative formula given by schwinger @xcite.   the purpose of this paper is to take the time dependence of the electric field into account, as properly as a semiclassical formalism would allow, and present a new source term for use in the qgp transport equation, based on the one - particle phase space of the x - ray component of the model.
ratios of percentiles from a single population may be of direct interest for many disciplines, but in particular it is very often used as a simple measure of income inequality.   the main results presented in this paper are first, showing that large sample distribution - free confidence intervals for ratios of quantiles based on standard theory have reliable coverage for moderate sample sizes. even for samples of size 10,000, the standard errors of ratio estimators can not be ignored ; thus one cannot assume that sample ratios are accurate just because the sample size is large.third, showing such procedures are resistant to outliers and to the presence of a small proportion of zero incomes in the population.
surface stress is an important microscopic indicator of the state of a crystal surface.   it can be measured by measuring the bending of a thin plate - shaped sample, which is a macroscopic measure of the stress - induced curvature of the sample. in this work   we present a new method for the determination of surface stress from the measurement of the slab curvature as a function of adsorbate coverage on a slab with variable curvature using atomistic molecular dynamics ( md ) simulations. to achieve this  , we extend the usual concept of variable cell md, pionereed by andersen and parrinello and rahman @xcite, to a case of a bent plate, where the curvature is a single, global lagrangian degree of freedom. under these conditions,   the surface stress can be extracted as a direct result of the calculation through elasticity equations@xcite. the theory and geometric considerations underlying our simulation are discussed.  also, the phenomenology of the bent plate is reviewed in order to extract the pertinent equations. finally, we present some initial applications of the method.
we present a systematic first principles theoretical study of the magnetic properties of model v - dilute fcc cu - v alloys by using the density functional theory ( dft ) approach together with the pseudopotential approximation for the electron - ion interaction.   the results show that the average magnetic behavior of the alloys is not necessarily given by the average properties of their corresponding isolated constituents, and that the observed phenomena are expected to strongly depend on the precise details of the local geometrical and chemical environment. in particular, we put special emphasis on the electronic and magnetic properties as well as the possible existence of multiple magnetic solutions in the systems, since if small energy differences are found among them magnetic fluctuations could be present in the samples.
exact solutions of einstein s field equations with axial symmetry play an important role in the astrophysical applications of general relativity, since the natural shape of an isolated self - gravitating fluid is axially symmetric. in particular, disk - like configurations of matter are of great interest, since they can be used as models of galaxies and accretion disks.   several classes of exact solutions of the einstein field equations corresponding to static thin disks with or without radial pressure have been obtained by different authors. in this article   we present a class of the functions mentioned above and use them together with the schwarzschild metric to construct more models of exact relativistic thick disks.
the effect of coulomb interaction on the current fluctuation in electron transport through a single - molecule magnet ( smm ) system is studied by means of shot - noise measurements and the full counting statistics ( fcs ).   the results show that the effects of the finite coulom interactions on the shot noise and the cumulant generating function ( cgf ) of the current can be fully described by the fcs, which may provide the full information about the probability distribution of transferring electrons between electrode and smm during a time interval.
we propose a simulation - based framework for numerical optimisation of ordinary differential equation models with steady state constraints.   we exploit the local geometry of the steady state manifold to move on the manifold and stabilise it using a continuous retraction operator. by reformulating the optimization problem to an unconstrained optimisation problem, we obtain an ode system which evolves on the nonlinear manifold defined by the constant steady state constraint. in the case of a locally strictly convex objective function,   the optimisation is performed using adaptive step - size solvers that allow the point to be projected onto the stable steady state manifolds. as many systems operate in steady state and/or undergo fast equilibration, constrained optimisation problems are widely studied. here  , we show that the proposed optimisation method is efficient and robust for such problems.
we present new observations of  in four lyman break galaxies ( lbgs ) at @xmath12 using alma.   the observed galaxies are fainter than previously reported and show a change in their physical properties between@xmath46 and @x Math19, which suggests that they have a low dust mass. for two of them we set quite stringent constraints on the non - detection of the  line, whereas the third one showed a detection from a region that is not centered on the galaxy.. none of the @x math19 galaxies are detected in the far - ir continuum, which suggest a lowdust mass. however, the only exception is a1689-zd1 with a clear detection of thermal dust emission, which strongly suppresses the uv - continuum. to assess the nature of the sources responsible for this change in the physical properties of these galaxies, we used a combination of spectroscopic and theoretical analyses of the x - ray diffraction data obtained from the cosmic microwave background ( cbm ) and the raman spectroscopy of the visible spectrum of the l157.74@xMath16 m line.
in wave - particle complementarity, the result of any interferometric experiment done with a single quanta sounds as if the quanta has passed through several paths like a classical wave ( e.g., the interference pattern forms ) or as if it haspassed through just one path like a classic particle ( one special path can be attributed to the quantas ).   this principle is a cornerstone of copenhagen interpretation of quantum mechanics. in this paper  , we show that wavelike behavior and particle - like behavior can be quantified in a symmetric two - path interferometer by erasing the potential information on the ancillary system s path from the results of the experiment. using the quantum erasing procedure, we find that the visibility of the interference decreases when the entangled state is not maximal but increases when the entangle is maximally entangled with state @xmath1 of another physical system which is unbiased to the basis@xmath2. for each subensemble of the output data of the interferometry accorrding to the measurement results, the trade - off between wavelikes and particles shows a significant increase in the squared distinguishability.
we explore the topological interference management problem in a class of linear wired interference networks with time - varying ( alternating ) connectivity.   we assume that the network topology is fixed throughout the duration of communication, and that the transmitters are only aware of the channel state information at transmitters ( csit ) through 1-bit feedback indicating whether an interference link is present or not, but no knowledge of channel coefficient value is available to the receiver. for each channel coefficient,   the csit is only comprised of a binary variable that takes value 0 if the transmission field is larger than 2, and 1 if the transmitting field is smaller than 2.we show that the results can be directly translated into degrees - of - freedom ( dof ) results for corresponding instances of wireless networks using the same principles as those in @xcite.
the crystal ball detector has been used to measure the @xmath2 production of neutral final - state particles at t@xmath5 = 625  mev in aqueous solution.   the crystal ball measurements have provided very precise cross sections with broad angular coverage, and the data are invaluable for detailed partial - wave analyses. here   we consider how these data have impacted ongoing studies of the low - lying baryon resonances.
the origin of the very high energy ( vhe ) cosmic rays is one of the most important problems in modern astrophysics.   the author has argued that due to the frozen - in condition plasma particles follow rapidly rotating magnetic field lines and as a result, undergo very efficient centrifugal force, leading to efficient acceleration of particles, which after gaining enormous energy can radiate away vhe photons. by taking into account the observationally evident fact that cosmic rays are in force - free regime, we have found that in order for particles to reach the mentioned dynamical pattern the channels must have the shape of the archimede s spiral.in this paper we consider particle motion in two dimensions alongside a wire anchored to the central object which is rotating with angular velocity @xmath0. 	 the form of the wire is given in polar coordinates as@xmath1 and consequently the channel is located in the equatorial plane.    the radial and radial directions of the wires are taken from the experimentally observed rotation of the magnetosphere of pulsars and active galactic nuclei ( agns ). using a theoretical model of centrifugal acceleration   we have shown that the effective angular velocity of the particle in the laboratory reference
the nature of dark energy has been the subject of much debate over the past decade.   supernovae data, which gave the first indication of the accelerated expansion of the universe, are expected to elucidate this interesting question further. in this paper   we present a non - parametric method based on smoothing the supernova data over redshift in order to reconstruct cosmological quantities, including the expansion rate, @xmath0, and the equation of state of dark space,@xmath5, in a model - independent manner. by using the results of detection of baryon acoustic oscillation peak, we reconstruct @x Math5 from the gold supernova data and then compare the derived value with the results for the snls data. here  , we show that the improved smoothing method is able to extract information about the expansion history of universe up to a redshift of ~2 independently of the assumption of any Cosmological model. as the quality of the data improves, the accuracy of the smoothing algorithm increases while the precision of the derived values decreases.. the derived result obtained by using this method is, therefore, expected to be model- and functional - independent.
conjugal normal form ( cnf ) decompositions of global constraints are a promising mechanism to implement them in constraint toolkits.   we show that circuit complexity can be used to resolve the open question of which global constraints can be effectively propagated using simple encodings @xcite. for each global constraint,   the propagator can be computed by a polynomial size monotone boolean circuit if and only if the propagation algorithm can be computable by a monotonesome boolean circuit. here  , we extend these results to constraints of bounded arity with domains given in extension since such decomppositions can be translated into clauses of polynomially sized constraints.
the spectroscopic technique has been the most successful method for determining the atmospheric parameters of hydrogen - line da white dwarfs.   the opacity of the hydrogen lines, which are the dominant features observed in optical and uv spectra, is one of the most important aspects of the model atmosphere calculations. in their preliminary analysis of da white dwarf models, @xcite found a lack of internal consistency between the spectroscopy solutions obtained when an increasing number of balmer lines were included in the fitting procedure. to address this problem, they proposed to parameterize the value of the critical field used in the non - ideal equation of state of hummer & mihalas ( hm88 ) to mimic the non-ideal effects in the line wing opacity. here  , we provide a framework with no free parameter by improving the physics of the line profile calculations using a new approach based on the unified theory of stark broadening from vidal, cooper, & smith ( vcs ). as a result, we show that the model spectra of a typical da star with two or more lines of lyman lines are significantly more consistent than those of a star with only one line of balmers.
thermal decomposition of silicon carbide ( sic ) @xcite is a versatile technique to dislodge si atoms from the sic network, leaving behind high quality graphene flakes or islands.   the process that leads to the formation of this type of supported nanographene has still to be fully unraveled. in this paper  , we resort to density - functional theory ( dft ) based calculations aimed at clarifying the pathways along which si atoms are dislodged from the Sic network and tracking the processes that lead to the initial carbon seeds from which graphene can subsequently grow. by considering all possible desorption pathways from nanofacets, we provide a comprehensive picture of all possible reaction pathways that the system can exhibit upon desorbed si atoms, including the fate of the si atoms that leave the sia network. on the other hand, we also work out the associated energy barriers characterizing the possible reaction paths, tracking them from the edge sites from which the initial graphene seeds can be formed.
the dynamics of the positive charge density produced by the cosmic rays and by the contamination in natural argon has been investigated in a massive liquid argon time projection chamber ( lar - tpc ), evaluating its impact on the electron signal in massive argon detectors.   the study is particularly relevant for the new generation of neutrino experiments foreseeing drift paths of many meters, where the primary electrons produced in the liquid drift to the gas region where they are extracted and accelerated with the production of a townsend avalanche. at the same time, given low diffusion of the ions in gas argon relative to the typical size of the amplification region, a non - negligible fraction of the ar ions can drift back to the liquid interface along the same field lines of the extracted electrons. when the distance between the ion and the liquid - vapor interface is greater than several angstroms, the liquid can be treated as a continuum, thus an approximated description of the dynamics can be obtained solving a boundary condition problem between different dielectrics with the mirror charge method in a single dimension @xcite. taking into account that the relative permittivity is @xmath11 for liquid argons and @x Math12 for argon vapor,
we have investigated the structural properties of si epitaxial layers deposited on si(001 ) vicinal substrates depending on the growth temperature and the rate of si deposition.   we have found that the step - flow growth goes on at the temperatures above 600 whereas the island growth takes place at the temps below 600. for surfaces tilted towards the  direction,   the surface is composed by s@xmath2 and s @xmath3 monoatomic steps.  in contrast, for those tilted towardsthe  direction a mixed s@Xmath2+s@x math3monoatomic step structure is observed. when the si deposition rate is reduced from  0.3 / c to 0.1 / c, the appearance of the structure formed by monoatomatomic steps runs along the  direction and formation of shapeless pits on the surface   is observed instead of the one formed by the bent monoatomatic steps. at the temperature of 550  , the transition mode of the epilayer growth, intermediate between the Island growth and the Step - flow one, is observed for both tilt directions.
the morgan - keenan ( mk ) system of spectral classification is a classical application of morphological techniques.   it is based upon the established reference frame of standard spectra, with empirical line - ratio criteria therein, and new spectra are described differentially relative to the standards, with observational parameters as similar as possible ( preferably identical ) to those of the standards. in this way  , errors and uncertainties in the subsequent procedures do not affect the description of the phenomena, which remains valid in the event of revisions or improvements to the latter ; and correlations or discrepancies with other kinds of data may be usefully investigated. when a new observational domain is opened to investigation, such as a new wavelength regime, a different metallicity in an external galaxy ( or region of our own ), or simply increased information content in higher quality data, the above principles apply fully. stated another way, an adequate image of the new phenomena must be formulated before they can be subjected to interpretation or modeling.this paper presents specific, practical examples of systematic trends and relationships, as well as peculiar phenomena, recently discovered in optical o - type horizontal ( temperature ) spectra by the application of morphology techniques, and suggests that systematic modeling relative to an
we are pleased to be adding our contribution to the collection of works in this volume, by many eminent authors in a wide spectrum of fields, in honor of rolf landauer s lifetime of contributions to our understanding of the physical world.   we will say a lot more about what those contributions have meant for us below, but we might note one important motivation which we have been given by rolf s many battles with the producers of conference books and special volumes such as this one : that the written word should be taken seriously, and that contributions, seriously written, should not languish on an editor s shelf waiting for slaggart authors or testy co - editors to do their neglected duty.
a lot of work in dynamical systems focuses on understanding different types of behaviors in a model, such as elliptical zones, hyperbolic trajectories, chaotic attractors, mixing regions, to name just a few.   one interesting tool is to partition the space - time domain into subregions based on certain quantity measured along with the passive tracer advected according to the associated dynamical system. here  , we propose an eulerian approach to the flow map computation for the finite time lyapunov exponent ( ftle ) which measures the rate of separation of a passive tracers with an infinitesimal perturbation in the initial condition, over a finite period of time. using this improved algorithm, we also propose a simple euleric approach to compute the isle, which is a measure of trajectory separation in a continuous dynamic system.
the interplay of antiferromagnetic ( af ) and d - wave pairing ( dsc ) order at low hole doping in multilayer cuprates is studied using renormalized mean field theory calculations.   the effect of interlayer couplings between the two order parameters on the coexistence of af and dsc order in a single layer is investigated.    the results show that the sublattice magnetization of af order and the pairing amplitude of dsc ordering are strongly dependent on the hole density, which is determined by the zero magnetic field shift on cu - sites in nmr experiments.
we consider the case of a georgi - glashow model of conformally coupled matter / gravity with scalar fields and non - abelian gauge fields.   we find that the effective action after symmetry breaking is dominated by einstein gravity ( general relativity ) in the long distance or low energy regime.
we take a variation of grover s algorithm for quantum search and translate it into a relativistic setting.   this variation can be though of as an effective procedure for energy transfer between classical objects. in the classical case,   the algorithm needs a number of steps proportional to @xmath2 to transfer the energy of a marked object to a non - marked object. here  , we show that special relativity predicts a smaller number of times needed to transfer kinetic energy from a large body of normalized mass to a small one. when the speed of light, @x Math3, is approached, the time complexity of the procedure can be reduced to a single step.
determining distances to galactic objects ( hii regions, pulsars and supernova remnants ( snr ) ) may help understand the kinematics of the milky way.   it can also provide direct evidence whether a snr is physically associated with molecular clouds, or if strong interaction between a snrs shock and surrounding clouds is possible, which is widely believed to be a source of tev @xmath3-ray and non - thermal x - ray emission in the milked way. in this paper, we re - measure the distance to two snrs : kes 69 which has 1720 mhz oh maser emission, and g21.5 - 0.9 which hosts a young pulsar and also has tev@x math 3-ray emission. by comparing hi absorption spectra toward galactic snr with respective hi and @x maths0co emission spectra along the line of sight, we previously revised distances to five snrs and several overlapping hii region. here  , we use the methods to directly re - Measure distances of two more snrs: kes69 which has 1833 mhzoh maser emissions and also hosts a pulsar at a velocity of 69.3
the external solar - type binary perturbing star, hd  80607, is visible at a projected separation of @xmath111000 au from its host star.   the planet hD  80606b ( @xcite ) has an extremely high orbital eccentricity and a sky - projected misalignment between the orbital and stellar spin angular momentum vectors, and experiences strong, episodic radiative and tidal forcing as a result of periastron encounters that sweep the planet a mere 6@xmath16 from the stellar surface. using the spitzer space telescope s irac detector, we have obtained a series of 676,000 photometric measurements of this system in two successive blocks of 50 and 30 hrs starting on ut jan 06 2010 and ending on jan 09 2010, with a 0.4 sec exposure time. for each image, we determine the background level of each of the 64 subarray images from the pixels located outside a 10 pixel radius, excluding any flagged hot, bright or peripheral pixels. using a histogram of the measured background pixel values we discard the 3@x Maths outliers from the background pixels and subtract the median of the undiscarded background pixels from each image.
the lense - thirring ( lt ) effect is one of the few predictions of the einstein s general theory of relativity which is still awaiting for a direct and reliable observational check.   it is a consequence of the off - diagonal components @xmath0 of the space - time metric generated by a weakly gravitating and slowly rotating massive body of mass and proper angular momentum in the linearized weak - field and slow - motion approximation of gtr@xcite. here   we investigate the possibility of measuring the lt effect on the orbits of the galilean satellites io ( 1 ), europa ( 2 ), ganymede ( 3 ) and callisto ( 4 ) evolving in the gravitational field of jupiter in view of recent improvements in their ephemerides@xcites.. the orbital parameters of these satellites have been improved by using the jovian system as a proxy for the gravity of the central body. to test the validity of the proposed model,   the orbit of each satellite has been imaged with the gp - b spacecraft carrying four superconducting gyroscopes carried onboard with an expected accuracy of @x Math13 or better. from the results
quantum optics is a natural candidate for the experimental implementation of quantum information processing systems, thanks to the recent achievements in the manipulation of single atoms, ions and single cavity modes.   however with the recent rapid progress in the theory of quantum knowledge processing the protection of quantum states and their quantum dynamics is becoming a very important issue. in this paper   we propose a simple physical way to control decoherence and protect a given quantum state against the destructive effects of the interaction with the environment : applying an appropriate feedback. here   it is shown that the proposed feedback scheme is based on direct photodection rather than homodyne detection, and that it can be used to slow down the decay of a quantum state in an optical cavity.
the roots of random univariate polynomials are a classic problem in mathematics due to their numerous applications in many areas of mathematics and engineering.   numerical root - finding methods are widely used to study the roots of these polynomial roots. here  , we compare @xmath0-theory with a global approach used in the mpsolve package, which implements an efficient multiprecision univariate Polynomial solver that is efficient and effective at solving polynoma roots even as the degree increases. by means of gerschgorin s theorem applied to a particular companion matrix, we find that the global approach is more efficient than the local approach, which is based on the fact that the coefficients of the companion matrices depend on all of the roots. using this global approach, we show that the results obtained for the first two tests are better than those obtained using the alphacertified method, which uses only data computed at the test point.
the use of quantum channels to send classical information has many advantages over the use of classical channels.   one of these is the fact that it enables one to establish cryptographic keys in a way that is provably secure, a feat which has never been achieved classically. here  , we discuss the problem of distinguishing between quantum states using distinguishability measures. for this purpose, we consider ensembles of quantum states which have equal _ a priori probabilities and show that for two equally - probable pure states, this effect can not be demonstrated for the distinguishability measure @xmath11{\geq}d_{1}$, which leads us to consider enambles of@xmath12 states. for each state in the chosen ensemble,   the maximum probability of correct hypothesis testing and unambiguous state discrimination are taken as the best predictors of the state's distinguishability. by taking advantage of this ordering, we show that there is a generalised effect on the order of the distinguishable measures for each set of states in the ensemble, which is consistent with a related effect recently discovered by jozsa and schlienz@xcite.
we derive a general formula for the finite volume mass shift of s - wave bound states in a finite periodic volume.   the formula is based on the generalization of lscher s formula ( [ eq : delta_m - luscher ) for the mass shift to higher partial waves and the general mass shift for states with angular momenta up to @xmath14, which is used to describe the transformation properties of the quantum wave function with respect to the symmetry group of the periodic cubic box. using this formula, we show that the maximum mass shift can be described by the volume dependence of avoided level crossings between the two - dimensional system and the space of the finite area with periodic boundaries. when the system is simulated in a discrete spacetime lattice over a finite volume, the results are similar to those obtained from precision lattice calculations. as a result, our results can be used to probe the angular momentum and radial structure of the bound state wave function.
cyg x-1 is a proton - dominated optically thin solution of @xcite.   it is believed to be powered by accretion through an accretion disc, and its x - ray spectrum indicates the existence of a hot x - rays emitting and a cold reflecting gas. in this study   we consider the spectra of the outer corona, which emits via bremsstrahlung, comptonization, and positron annihilation, and analyze possible consequences of that. for the @xmath13- and@xmath14-bremssthalung emissivities given by numerical fits of @xaicite, we use the integration formulas of @xficite. to calculate the effect of compton scattering on the emission of the soft blackbody component, we follow monte carlo simulations except at high temperatures, @x Math16, and small optical depth.. we find that the intensity of the hard mev tail can not be explained by Comptonization in a corona and thus another mechanism must be considered.
the visibility graph of a simple polygon is one of the most well - known problems in computational geometry for many years, yet still to this date the best polynomial - time approximation algorithm for this problem is a @xmath4-approximation algorithm.   the key issue is a fundamental lack of understanding of the combinatorial structure of visibility inside simple polygons. here   we present a new approach to the visibility graph recognition problem which is based on the recently published work of orourke and streinu . using the geometric set cover problem as a case study, we show that the visibility graphs of simple Polygons can be characterized by the following : ( 1 ) the number of points in the polygon that collectively " see " each other if and only if the line segment connecting the points does not go outside thepolygon ; ( 2 ) the distance between the vertices of the vertex(s ) in the graph(
anomalous diffusion is the deviation of the mean squared displacement ( msd ) of a stochastic process with the probability density function to find the particle at position at time.   it is characterized by the deviation from the linear time dependence of ordinary brownian motion and is usually characterized in terms of the power - law form with the anomalous diffusion coefficient of physical dimension and an anomalous diffusivity exponent. since the milestone discoveries of superdiffusion in turbulence already in 1926 and of subdiffusion on larger scales in amorphous semiconductors over the last fifteen years, there has been a surge of interest in anomalous dynamics in numerous microscopic systems, in particular in biological contexts. here   we review the recent advances in our understanding of anomalous movement of tracers in the cytoplasm of eukaryotic cells using artificial crowders and the effects of temperature gradients on the diffusion of these tracers.
the sun spends about 17% of its life in states of subnormal magnetic activity or grand minima.   the currently leading theory of solar dynamo explains these states by randomness in dynamo parameters.. this paper shows that the correlation of the magnetic activity level with its hemispheric asymmetry naturally emerges in the dynamo theory and the increased asymmetry in epochs of global minima can be reproduced by solar dynamos with latitude and time dependent fluctuations in the poloidal field generation mechanism.
the thermal expansion experiment @xcite is a simple, low - cost demonstration for teaching students about thermal expansion.   we present a detailed description of the experiment and analyze two important sources of uncertainty that affect this experiment : ( 1 ) the mass and elasticity of the wire and ( 2 ) the measurement uncertainty of the thermal expansion coefficient. to account for their contributions to the height of the load, we explore different models of the wires, including an idealized model which assumes a stiff, massless wire and a more realistic one which treats the wire as both massive and elastic. in the latter model,   the wire is stretched horizonatally between two anchors and its mass is attached to its midpoint. by measuring the change in height of her mass, one can determine the temperature of the heat source and hence its coefficient of thermal expansion, which is used to determine the length of a wire and hence the effect size of the experimental experiment. here  , we describe how the wire s mass and elastance affect measurement of the heating process and determine the conditions under which their effects are negligible.
we have performed an optical and infrared photometric study of the environments of triplets of quasars at different redshifts on the scale of galaxy clusters.   we find that quasar triplets are associated with extremely rich clusters of galaxies at low redshifting ( z = 0.3 ) and high redshift ( z > 0.5 ). in particular, we find a cluster of seyfert 1 galaxies with a very compact quasar association ( @xmath6 50 kpc separation ) that is associated with a supermassive black - hole merger at redshift < 0.4. to investigate the environment of these clusters, we also study the group and cluster morphology, and the photometric properties of individual galaxies in the neighbourhood of each triplet.
the celebrated hoava - lifshitz ( hl ) gravity is based on the idea of the restricted invariance of the theory when the theory is invariant under the so - called foliation preserving diffeomorphism.   it turns out that there are two versions of hl gravity, the projectable theory with the lapse depending only on the time and the non - projectable one with the lag time depending on the spatial coordinates. in this paper   we perform the hamiltonian analysis of the @xmath0 gravity and show that the full diffeomorphic invariance is broken. on the other hand  , we show that all the terms which contain the spatial gradients of lapse are also broken by the same mechanism as the first version of non -Projectable hl gravitational theory.
we present results from new simulations that follow a disk - like dwarf orbiting in a " live " mw - sized halo with both a dark matter and a hot gas component, witnessing for the first time the combined effect of tides and ram pressure on the structure of a dwarf spheroidal ( dsph ).   the dwarf has a dark halo based on the milky way, a stellar and a gaseous component, and a mean density of @xmath11 atoms/@xmath4 within 150 kpc of the primary halo. at the same time   it has a hot corona consisting of ~20,000 gas and 30,000 star particles, as found in the local group ( lg ) dwarf irregulars ( dirr ). by simulating the dynamics of the halo, we show that the tidal mass loss of the dwarf satellite is due to stripping of the gas of its stellar component, which is caused by the combination of tidal shocks and ram pressures.. the observed observations suggest that the dilatation of the solar system could have been too large for photoevaporation to be effective.
percolation is a simple phase transition that can occur in a great many systems that exhibit branched network structure.   the percolation threshold is only known exactly for special classes of lattices, all in 2d@xcite. despite the paucity of exact results,   analytical formulas have been proposed to provide approximate predictions ( of varying accuracy ) for @xmath0 on different lattices. here   we review the power - law scaling formula of galam and mauger, which has been used to predict @x math0 for most lattices with coordination number @x maths1 and percolated sites @x Math2, and we show that this formula is not generalizable to all lattices and does not give an accurate prediction of @xMath0 for any given lattice.
a higgs boson has been discovered at the cern large hadron collider ( lhc )  @xcite, whose properties ; @xmath3, mass, spin, cp and observed number of events are consistent with those of the standard model ( sm ) predicted in the paper.   we discuss two higgs doublet models ( thdms ) with the @x math0 symmetry as the simplest realization of the diagonalized mass matrix for the charged - leptons without introducing any unitary matrices. by assigning the first and second generation lepton fields to be the@xmath0 doublet charge assignments for the quarks and higgsdoublet fields, we find that extra neutral and charged higgsbosons can be muon and electron specific ; namely, they can mainly decay into @x Math10 or @x maths11 and @xMath12 or @Xmath13, respectively, in one of four types of the yukawa interaction.    we show excluded parameter regions from the current lhC data in this scenario.. we then evaluate discovery potential of signal events from these extra higgs Bosons at the lhcs with the collision energy to be 14
the @xmath6 expansion of qcd is used to study the properties of positive parity exotic states.   the expansion is based on the fundamental theory of the strong interactions, and relates the chiral soliton model to the more intuitive quark model picture. in this paper   we assume the existence of the positive parity pentaquarks, and investigate their properties in the case that they have positive parity. a partial subset of these states with one heavy antiquark   are considered, and the effects of the spin - flavor symmetry and the orbital angular momentum are studied.
the two - dimensional melting of hard - core potential systems including hard discs or lennard - jones ( lj ) potentials has been an important subject of research in condensed matter physics both theoretically and experimentally.   one of the most important questions in the two dimensional melting, which has not been satisfactorily answered yet, is probably the question of how to determine the form of the inter - particle potential that is most favorable for the existence of the hexatic phase. in this work, we investigate how the characteristics of two-dimensional melting evolve as the value of the single parameter @xmath9 is varied from@xmath11 to larger values of @x maths12 and @x math13.. it is found that a system with a short range potential with @x Math13 exhibits a strong first order melting transition compared to the case of @Xmath15, clearly showing coexistence of solid and liquid. on the other hand, systems with a longer range potential are correlated with smaller angular stiffness and first order melt transition.
we propose a model for generating a simple directed random graph with prescribed degree distributions.   the goal of this model is to provide an algorithm to generate a simple random graph whose degree distribution is approximately @xmath0. in order to obtain a prescribed degree distribution,   vertices are given stubs or half - edges according to a degree sequence@xmath2 and these stubs are randomly paired to form edges. to obtain such a prescribeddegree distribution, the degree sequence @x math2 is chosen as i.i.d. erythroid random variables having distribution @x Math0. here   we show that the proposed model is able to match the degree distributions of the in - degree and out - degree distributions to those of the empirical distributions, and that the results are applicable to a great variety of examples, including the world wide web.
we present @xmath0- a preliminary idea of deploying a lightweight micro cloud infrastructure in the sky using indigenously built low cost drones, single board computers and lightweight operating system virtualization technologies such as unik kernels / dockers.   our paper lays out the preliminary ideas on such a system that can be instantaneously deployed on demand to provide internet access to the user on demand even in the absence of a terrestrial infrastructure e.g. rural / remote areas or disaster zones.
m82 x-1 is the most luminous ultra - luminous x - ray source ( ulx ) in nearby galaxies.   it has been considered an intermediate mass black hole candidate because of its unusually bright energy spectrum, which is much harder than what is expected from standard accretion disks around intermediate black holes. here  , we present a precise spectral analysis of _ xmm - newton _ data of m82 X-1 for a 105 ksec exposure using the european photon imaging camera ( epic ) pn and mos in the full window and medium filter mode. by using the much better statistics than previous observations, we were able to tightly constrain the spectral models of the two competing models that have been proposed to explain the " too hot a disk " problem of m92 x-2 and other ulxs : the first model assumes that the accretion disk is not in the standard disk state where the gravitational energy released is converted into optically thick radiation, but in a _ slim disk _ state where radial energy advection is dominant, and the second model assumed that such disks are shrouded by hot, compton thick clouds. with the use of the latter model, we show that the
we present a map of the water emission from the central portion of the orion molecular cloud obtained with the _ submillimeter wave astronomy satellite ( _ swas _ ).   the emission is composed of both a broad velocity feature associated with the shocked gas and a narrow feature that likely arises from the quiescent gas in the orions molecular ridge. to our knowledge, this is the first definitive detection of water in the extended, cold molecular gas.
stellar evolution models are pivotal ingredients in order to understand the evolutionary properties of the various stellar populations present in both resolved and un - resolved stellar systems, so that they play a fundamental role in assessing the  and the contribution of the different blocks that contribute to build the galaxies.   in view of this relevance, it is quite important to establish the level of accuracy and reliability of present generation of stellar models : this can be achieved only by comparing theoretical predictions with empirical constraints. during the second half of the last century  , stellar evolution theory has allowed to properly understand the  of the Various branches observed in the color magnitude diagram ( cmd ) of both galactic globular clusters ( ggcs ) and open clusters ; this notwithstanding for a long time these theoretical predictions were accounted for with an uncritical approach.. more recently, this approach to the theoretical framework drastically changed and more critical assessments were adopted. at the same time, models computed with this updated physics have been extensively tested against the latest observations, and this has also contributed to increase the awareness that it is no more possible to neglect physical processes as radiative levitation, rotation, magnetic fields, considered secondary physical mechanisms until few years ago.
time - series photometry is a key tool in the study of pulsating white dwarfs.   we have developed a laboratory experiment that simulates the photometric study of these stars using a custom light emitting diode ( led ) controller and a commercial ccd ( charge coupled device ) camera system. for the laboratory experiment,   the experimental apparatus consists of a light - tight box with a ccd camera and a small lens at one end imaging a pair of leds attached to a plate on the inside of the box at the other end. as part of the development of this ccd photometer, a light box with controllable light emitting diodes ( leds ) as artificial stars was constructed for bench testing the instrument. here  , we describe the experimental equipment and the analytical tools required to extract the periodicities that are present in the detected time - series data from the simulated light curve data.
we consider a model of a lattice gas of two species of particles and holes on a fully periodic lattice in two spatial dimensions.   we drive the system out of equilibrium by bias the hopping rates of the two species in opposite directions, acting on opposite ` charges'( though we stress that there is _ no coulomb interaction ). to study the nonequilibrium steady state, we combine the results of previous work on the katz et al kls model with those of schmittmann et al @xcite and the shz model for a non - interacting two - species model. while the klsmodel phase - separates, via a continuous transition, into high- and low - density strips aligned with the field, the chisquare model orders into mass - segregated strips, which drift from equilibrium if a charge imbalance is imposed. here  , we investigate the critical behavior of these strips using a novel universality class with exponents distinct from the ising ones proposed by zhang et al [ m. j. l. schmittman, r. b. w. lehane, p. d. van der waals, c. hirschberg, e. t.
the aim of this paper is to present a set of descriptive criteria to identify  structure  in early child grammars.   these criteria are used to build up a network of syntactic networks from the peter corpora of childes database @xcite using the dga - annotator@xcite. with these criteria,   we want to study syntax with modern methods of complex network theory. here  , we discuss the scope and validity of the conceptualization of relations between syntactic relations within a network as well as the structural criteria employed in the construction of the associated networks. finally, a brief compendium of network measures is shown, as wellas an illustrating example.
the lhcb experiment has a unique opportunity to study heavy baryons produced abundantly in proton - proton collisions at the lhc, as it is able to efficiently trigger @xcite on both muonic and purely hadronic final states and to reduce the high level of hadronic background.   it was mentioned in @xmath1 that the reconstruction of charged hyperons, and in particular the and beryons, was particularly inefficient in the lHcb detector because of long - lived, secondary lambda baryon decaying outside its acceptance. here  , we present an alternative reconstruction method aiming to address this inefficiency and to promote the study of decay channels containing a or a at lh CBc. by combining the results of the focus collaboration's kink reconstruction with the results from the analysis of the decay channels mentioned above, we propose a new reconstruction method for the reconstructed momentum of charged particles in the Lhcb detector. using this method,   we show that the decay products of the @x math0 decay can be reconstructed into a proton and a charged pion of opposite charge, which are then used to reconstruct the momentum of the charged hyperon through the different elements of
the continuous - time random walks ( ctrws ) are widely used in building up models of anomalous diffusion and transport in physics and biology.   the telegraph equation was proposed as an alternative to the diffusion equation, which is widely used for approximate macroscopic description of nonanomalous diffusivity and brownian motion. in this paper   we investigate how accurate are the approximations to the delayed ctrw provided by the te Telegraph equation provided by its extension to the gamma - distributed waiting time delayed c trws ( dctrws ).. we show that the diffusion equations, being the correct limit of the dctrms, gives a precise approximation to the dcrws.,we find that the one - dimensional diffusion equation is the correct model for the ddrws when both the waiting time and the jump length are coupled random variables.
surrogate tests are useful tools to assess the statistical significance of our calculations even when we have only a very limited amount of observations. in this communication,   we discuss the algorithm to generate surrogates for pseudoperiodic time series using monte carlo hypothesis tests.   the surrogate test is a proper tool to evaluate the reliability of our results in a statistical sense.
the one - dimensional asymmetric simple exclusion process ( asep ) is one of the most typical models of interacting particle processes where particles diffuse to a preferred direction with hard core repulsive interaction.   the aim of this article is to analyze the dynamics of the diffusion of a particular particle in the one - dimension asymmetricsimple exclusion process. among various studies on the topic, we focus on the problem of the diffusivity of a tagged particle in an initial condition and the time evolution of the mobility of the tagged particle when @xmath2 is large ( but finite ). under the initial condition, we find that the diffusion property of the tag particle depends on the initial conditions and the exclusion effect through hard - core repulsion. for the fixed initial conditions, the diffusion exponent of the tagging particle increases from 1/2 to 1/3 while for the anomalous initial conditions it decreases from 1-to-1/3.. the limiting behavior of the tags particle as both @x Math2 and time go to infinity is also investigated.
the central parts of our galaxy were prospected by baade ( 1946 ), in order to detect its nucleus, and to have an indication of the morphological type of the galaxy.   the so - called baade s window was revealed, and from variable stars identified in the field, the bulge stellar population was identified as population ii. since then, several comprehensive recent reviews have addressed the stellar populations, both field and gc, in the galactic bulge. in the following   we describe recent advances on detailed chemical abundances, distances, kinematical properties and hints on possible association with subsystems in the central region of the Milky Way. also, we prepare for the future by defining a bulge gc sample, which includes suggestions for future studies, in terms of unstudied objects.
we propose an entangling scheme to cool two atoms inside an optical cavity into a maximally entangled state.   this is achieved by using level shifts and external laser fields such that only the target state of the system experiences off - resonant driving which couples resonantly and sufficiently strong to rapidly decaying excited states. as in laser sideband cooling of trapped ions,   the state preparation scheme employs a non - zero atom - cavity coupling constant and spontaneous emission of photons from excited states with decay rates of up to 20 s. the fidelity of the final state reaches one when the detuning of the targeted state becomes much larger than the relevant laser rabi frequencies and decay rates.
the @xmath2-ray  sky has been extensively studied by the compton gamma ray observatory ( cgro )@xcite and other space - based and ground - based telescopes in the last decade.   these observations have revolutionized our understanding of extragalactic phenomena such as blazars and gamma ray bursts, as well as those within our own galaxy, such as pulsars. however, with the effective turnoff of the egret @x maths2-rays instrument on the cgro due to the nearly complete consumption of its spark chamber gas, there will soon be no operating instrument capable of observing the @x Math2-Ray  sky in the energy interval @x math3 to @xMath4 gev.. future instruments with sensivity in this unexplored region, like agile @xcite, recently approved by the italian space agency ( asi ), or the proposed glast @xaite payload, may uncover exciting new phenomena.
the purpose of this paper is to describe a series of introductory physics courses that we have reformed at the university of california at davis ( uc davis ) over the past few years.   the courses are known as clasp ( collaborative learning through active sense - making in physics ) courses and are now the standard introduction to physics for bioscience majors at ucdavis. while the general purpose and the general structure of the course has been consistent throughout its existence, the main differences between clasp and the courses that it supplanted are in the order and organization of the physical ideas that we include in the curriculum. among these are the way in which the course is organized around a set of about two dozen models that physicists use to describe the major features of how the world works. by focusing on the main ideas of physics and the unity inherent in the structure of physics rather than on the many detailed examples and algorithms that are used to show how these main ideas play out in the world, clasp courses are more likely to be useful to students who are learning the subject for the first time and who are judging " what is important to really understand" by the number of problems that they have to solve using the various ideas and
the abundance - metallicity relation of extremely metal - poor ( emp ) and very metal -poor ( vmp ) stars has been clarified by observations of very high quality spectra.   this relation is expected to provide the information of supernovae of population ( pop ) iii ( the first generation ) massive stars and the first stage of galactic chemical evolution ( gce ). in order to clarify the characteristics of first generation stars, we should investigate nucleosynthesis in the candidates of these stars as well as the observed variations of the abundance distributions of the emp and vmp stars. from theoretical viewpoint, the abundances of most of the observed elements are between @xmath9 and 0.5 for most of observed elements @xcite, and the small scatter around the average values deduced from the new observation is much smaller than found in earlier studies. a mixing - fallback model for the hypernova ( hn ) yields in the innermost region of the pop iii sn explosions is proposed.
abstractultracool dwarfs are very low mass stars and brown dwarfs that are capable of generating and dissipating large - scale axisymmetric magnetic fields.   we present the first very long baseline interferometry ( vlbi ) observations of the well - studied m8.5 dwarf tvlm513 - 46546 with the vlba, the first such detection for any ultracool dwarf. in particular, these observations have sufficient angular resolution to detect astrometric shifts of a few tenths of a milliarcsecond that may be exerted by a sub - stellar companion on a @xmath7 d orbit with a period of just a few hours. moreover, they also allow us to directly image a radio - emitting companion down to milliarticulate scales.
we use photographic plate material with longer time baselines than published previously, in order to determine the proper motions and membership probabilities of stars in the regions of two very young galactic open clusters ngc 2244 and ngc 6530.   we find that the mass segregation effects of mass segregation are present in both clusters, and that the more massive members of the cluster are more likely to be more centrally concentrated and/or have a distinct distribution in velocity space compared to the lower - mass members. using the webda open cluster database @xcite as our guide, we calculate the global stellar initial mass functions ( imfs ) of the star - forming open clusters at the equatorial and galactic coordinates of ngc2244 and ng 6530, and compare these results with those of previous studies using near - infrared imaging from the two micron all - sky survey ( 2mass ) and the photobleaching study of the monoceros ob2 ( mon ob2 ) association.the results show that the observed mass segregation is not due to the formation of new stars, but rather to the evolution of the existing stars. for each cluster,   the mass of the most massive stars is significantly higher than that of
radio emission associated with the development of extensive air showers ( eas ) was investigated in the 1960s at the nanay radio observatory  @xcite.   the codalema experiment is a new effort to investigate the radio emission of eas candidates using a wide band antenna array and sampling of the electric field over a few hundred meters range on the ground. here  , we describe the experimental set - up and the selection of eas radio candidates as well as the first observations on their electric field lateral distributions from a few illustrative examples. for each candidate,   an event - by - event description of the electromagnetic shower- signature is provided along with the study of the influence of the field amplitude on the observed transient radio signals.. the results show that the most common source of radio signals is a vertical shower falling upon the detector, followed by a horizontal shower falling on the surface of the detector and then a dipole shower falling onto the detector itself. during the latter phase, the average electric field spread is more or less constant depending on the location of the shower core and the presence of the primary particle. while the main focus of the present study is on the current state of knowledge about the evolution of the initial
quantum key distribution ( qkd ) has become one of the most important branches of quantum information.   quantum communication is based on the principle of quantum mechanics, and the noncloning theorem forbids the eavesdropper eve to eavesdrop the quantum signals freely and fully as her action will inevitably disturb the unknown states and leave a trace in the outcomes obtained by the two legitimate users. here  , we present a single - photon transmission scheme with linear optics against collective noise @xcite, in which only passive linear optical elements are required. for this scheme,   the time degree of freedom of the polarization of the photon is introduced to form a subspace that is not impacted by the collective noise, and then the effect of noise is cancelled by selecting the final state arriving at a special time slot.    the proposed scheme is efficient and convenient except for the use of pockels cells ( pc ).
serrated signals are ubiquitous in  stick - slip " physical systems ; examples range from earthquakes, through barkhasuen noise in magnetic systems, to stress and energy as a function of strain in amorphous solids.   the analysis of such signals often tends to seek power - laws to describe the statistics of the magnitude of serrated events. in this paper   we stress that a more complete understanding of the stats of such phenomena calls for scaling functions which incorporate knowledge of the system - size dependence. using a two - dimensional kob - andersen @xcite binary glass - former with a 65:35 ratio of point particles a and b having equal mass, we show that the small energy drops tend to be system size independent in agreement with a localized event. by combining the system size dependence with the strength of the scaling function we find that the scale functions reveal crucial information pertaining to the underlying physics responsible for the serrated signals.
mergers of two white dwarfs have been proposed as progenitor systems of type ia supernovae ( sne ia ) by @xcite and@xcite.   more than 25 years later, however, we are neither able to confirm them nor rule them out theoretically nor observationally. here   we present a new method for simulating the merger of two equal - mass white dwarf systems with a mass ratio of one with an unprecedented resolution of @xmath5 particles using the gadget code. in order to test the role of initial conditions and resolution in these mergers  , we show that the formation of hotspots on the surface of the merging white dwarf can be prevented by a new timestepping mechanism which is based on the use of a nuclear reaction network coupled to the equations of hydrodynamics to account for the energy release from nuclear reactions during the merger.
the extent to which the normal state of the high @xmath0 superconductors is anomalous has long been debated.   the most conclusive evidence for a break - down of fermi liquid theory has appeared relatively recently via a ( pseudo)gap in the fermionic spectrum with onset temperature@xmath4. here  , we present a natural extension of time dependent ginsburg - landau ( tdgl ) theory and associated transport coefficients which addresses higher temperatures @x math4 well outside the usual limited range of applicability near @x Math0. at the self consistent hartree level   it is shown that the bosons appear as quantum rather than classical fields and the effects of the pseudogap phase are stabilized by going beyond the usual gaussian approximation. when the bosonic degrees of freedom are included in the pair fluctuation scheme, the corresponding fermion pairs recombine and dissociate into fermions. below @x maths0 the counterpart of these pre - formed pairs appears as non - condensed bosons. using this new model, we establish a quantum extension of tdgl theory which is amenable to detailed transport studies at higher temperatures above @xMath4.
we present a few  mode galerkin model of the spatiotemporal evolution of the concentration field in a binary fluid.   the model is based upon a careful analysis of the temperature and concentration balance of the fluid in liquid mixtures. with it   we explain the whole bifurcation scenario from stable squares at onset up to stable rolls. for positive separation ratios,   this process is driven by the soret effect, which generates concentration gradients in response to the externally applied temperature difference and to local temperature gradients. for negative separation ratios ( e.g., 0.5 and 1 ) the convection is driven mainly by the solutal gradient established via the Soret effect. for the intermediate regime, where the stability changes from stationary squares to stationary rolls  , there exists another 3d structure, the so  called crossroll pattern that bifursates out of the stable square branch and merges with the roll branch at higher separation ratios. for larger separation ratios the concentration homogenizes and the fluid behaves more like a pure fluid. as a result, the equilibrium between the two types of convection states is dominated by a strong nonlinear advection and weak
hydrogen bonds are important interactions present in different systems in nature.   particularly, biological macromolecules as proteins, nucleic acids and carboxylic acids have the molecular groups nh and oh in their structures. these groups induce the hydrogen bonds which are essential to stabilize the structures and play an important role in the behavior of these macromolcules. in this work   it is proposed that quantum confinement effect is the main cause of delocalization of the vibrational spectrum of nh or oh groups when hydrogen bonds are formed. to overcome this proposal we used an analytical methodology based on the variational method associated to supersymmetric quantum mechanics, ( sqm ). by considering the schr@xmath2dinger equation depending on a potential with a potential barrier, we find that the vibrations of the groups studied are better described by the one - dimensional morse potential. if not by the potential barrier ( without confinement ) this potential presents exact analytical solution, @xcite. however, by considering both the solvation and the enthalpy of the potential, we obtain a more accurate solution for the problem.
we study the self - organized criticality ( soc ) @xcite on the ternary social networks.   we find under specific conditions the soc to be observable. for the small - world network, we find the way of construction have an influence on the occurrence of the avalanche. in the binary social networks,   the soc is observed when the nodes are connected to all the others by a hamiltonian and the geometrical temperature which is determined by the structure of the network without manual setting. based on our model, we obtain the distributions of each triad relation and the time needed for dynamic balance both for the binary and the teranary cases.
the inner region of the milky way ( mw ) hosts multiple components such as the bar and box / peanut ( b / p ) bulge, the thin and thick disks, and the inner stellar halo.   stars in the galactic bulge occupy a wide range in the metallicity distribution function ( mdf ), with  being the most metal - poor. here   we use n - body simulations to investigate the kinematics and spatial distribution of the metal -poor stars that have been detected in the bulge. using these simulations, we show that the density profile of the rr lyrae stars ( rrls ) in the inner bulge is spheroidal with a slight elongation inside 1 kpc, and that the radial velocity ( rv ) of these stars is barred, but that they are not part of the x - shaped structure seen in red clump giant stars ( e.g. *??? * ). by combining these new data, detailed studies   can now be made of the properties of the star population in the outer region around the galactic bar
we define a  sociotechnical system  as one involving interactions between autonomous social entities such as people and organizations mediated by technical components.   we show that the centralized conception of socioteschnical systems is not applicable to open systems because they are properly viewed as societies of principals, which can differ in their membership and structure dynamically. for example,   managed care organizations ( mcos ), hospitals, physicians, employees, and consumers can join or leave the managed healthcare system of their own volition.. principals act according to their own private business policies, some of which may not have been envisaged by the stakeholders. therefore, we propose an interaction - oriented software engineering approach to the design of software components for open sociotoxic systems. using this approach, we describe how to elicit, model, and manage the requirements of the social components so that suitable software components may be designed.
a laplace transform method for the calculation of the electromagnetic multiple photon emission probabilities at ultra - relativistic energies is proposed.   it is based on the theory that the probability of multiple soft photon emission factors factorize, expressing through the same classically calculated spectral intensity as the total energy deposition in a detector by the electrons in the radiator. to obtain the multiphoton spectrum,   one needs to resum all @xmath2-photon probabilities while holding the total irradiated energy at a preselected value. here  , we discuss the application of this method to study the shape of the soft part of the radiation spectrum from electrons in an amorphous medium, and to investigate the possibility of the shower length reduction due to coherent radiation effects.
the lyman break technique, which uses the expected spectral features of the galaxies we hope to find, is a powerful method for discovering large samples of high - redshift star - forming galaxies.   however, it relies on robust continuum detections in multiple images, as well as a very deep dropout filter, and requires followup spectroscopy to confirm the selection criteria and determine the redshift selection function. here  , we review the current state of the art in this area, and discuss the limitations of the method.
we combine current data on cdm cosmologies and star  formation in the most straightforward way.   we find that the abundance of virialized dark matter halos in the milky way is very low at redshifts as high as @xmath7, and that the first stars are formed with a low mass at Redshifts up to @x Math2.5. using a simple semi  analytic approach, we derive the expected number  flux relation and angular size distribution of these star clusters from the observed redshift evolution of the abundances of star  forming clouds and a detailed composite model spectrum for a low  metalicity stellar population with the local scalo initial mass function ( imf ). based on this model, we show that the pre  galactic population of stars reionize the universe by a redshift of@xmath14, and the consequent damping of microwave anisotropies on small angular scales is detected by map and planck.
we present a probabilistic method for enforcing adherence of the marginal probabilities of a multi - label model to automatically discovered deterministic relationships among labels.   we focus on pairwise pairwise positive entailment and exclusion relationships, where presence of one label is associated with presence of the other in all instances of a dataset. using a bayesian network,   these relationships are represented as soft evidence in the network and adjusted through probabilistically inference. our approach offers robust improvement in mean average precision compared to the standard binary relavance approach across all 12 datasets involved in our experiments.. the discovery process helps interesting implicit knowledge to emerge, which could be useful in itself.
we propose a private key cipher for multiple access communications using orthogonal frames.   the cipher is designed to be computationally fast, computationally efficient, and robust to brute force attacks. in this paper  , we demonstrate that this cipher is vulnerable to a chosen - plaintext attack.
a universal model for the dynamics of nonlinear systems close to critical points ( like the threshold of emission in a laser ) is derived by means of a complex swift - hohenberg equation with parametric gain, which describes a photorefractive oscillator ( pro ) under the injection of rocking forcing @xcite.   we show that the model described by this equation can be used to describe lasers with small detuning when rocking forcing is present, as well as we generalize the result of @xcite to more general setups.
an adaptive population is a population of agents that adapts to each other through adjusting the payoffs of their strategies.   the payoff function is crucial to the mechanism of adaptation, as it helps the agents to assess the preferences of their decisions, hence inducing them to take certain actions when they experience a similar dynamical environment in the future. for example, the ways the agents evaluate their strategies in financial markets have a large influence on the market behavior. here  , we investigate the effects of the diversity of strategy preferences on the behavior of an adaptive population using the minority game ( mg ) and the generating functional @xcite. by considering the dynamics of the population variance, we find that the distribution of the buyer population is double - peaked for a payoff function that favors a large winning margin, because the agents have adapted themselves to maximize their payoffs. also, the initial preference of an agent towards the individual strategies she holds is influenced by the complexity of her strategies. however, the overall population variance is not significantly affected by the diversification of the strategy preferences.
quantum information has been attracting computer scientists as a new computing paradigm. to develop a sound theory for handling such quantum information, we need to understand the structure of quantum information from the viewpoint of information processing.   voronoi diagrams have been playing a central role to represent the proximity relation of point set, etc. with a wide variety of applications in many fields. here, we introduce a method to calculate holevo capacity using vor on the bloch sphere by the fubini - study distance and the bures distance. also, we describe other voronsi diagrams on the sphere which are obtained by taking a limit of the vorontoi diagrams used in the calculation of holevoxel volume expansion ( holevo ) capacity. finally, all these diagrams are shown to be identical.
the planetary nebula ngc6369 is a wc4 star with a complex morphology, consisting of a main bright annulus of diameter 40, and fainter, curved outer structures on two sides in the e - w direction.   we have determined the optical+ir luminosity of this star using flux values from the literature, and calculated the spectral energy distribution ( sed ) of the star over a range of wavelengths from 0.44 to 1100@xmath15 m. the results show that the central star has a temperature of @xmath10.0 kpc, an expansion velocity of @Xmath13 km s@x Math14, and radial velocities of -106km.s@x math14 and -101km.a.m.we propose that the observed 2-d morphology of ngc 6369 is not due to the same 3-d gas distribution as has been shown by @xcite, but rather to the formation and evolution of the system.
the casimir effect is the regularised difference between the vacuum expectation value of a hamiltonian with and without the external conditions demanded by the particular physical situation at hand.   it is well known that the one - loop vacuum energy shift associated with a quantum field can be evaluated from the definition of the casimir energy, which is the sum of the fluctuations of the quantum field in the spacetime under external conditions. here  , we present a simple and effective way of evaluating this effect, based on well - known theorems of complex analysis, namely the cauchy integral formula and the mittag - leffler expansion theorem for the @xmath5 dimensional slab - bag model, in which the quark field is constrained into a region bounded by two infinite hyperslabs separated by a fixed distance. to test the generalizability of the method, we apply it to the case of a confined fermionic and gluonic quantum field living in a@xmath0 dimensional ultrastatic flat spacetime, and obtain its exact solution in terms of whittaker functions. finally, we consider some particular limits and check coincidence with some other results.
the electronic structure of the @xmath0 transition metal monolayers deposited on the bcc(001 ) tungsten surface has been determined by means of spin - polarized calculations within the local density approximation ( lda ).   the results show that the adsorbate layer of the monolayer is in a disordered state, e.g., it is not magnetically antiferromagnetic but rather in a ferromagnetic state. to explain the observed magnetic ordering,   we have applied the tight - binding linear muffin - tin orbital ( tb - lmto ) method in the framework of the atomic sphere approximation ( asa ) and the exchange - correlation potential of vosko, wilk and nusair @xcite. for the non - magnetic ( nm ), ferromagnetic ( fm ), and disordered local moment ( dlm ) states of the films, we have used the coherent potential approximation ( cpa ) with and without surface relaxations. using the lda, we estimate the local ( atomic ) moments in the @Xmath0 metal overlayers and determine their mutual alignment as a function of coverage.    the results
we derive exact finite - size corrections for the free energy and the specific heat of the critical ferromagnetic ising model on the @xmath2 square lattice with brascamp - kunz ( bk ) boundary conditions and compare such results with those under toroidal boundary conditions.   we find that when the ratio@xmath3 is smaller than 1 the behaviors of finite - Size corrections for free energy @x Math0 are quite different for bk and toroidal boundaries conditions ; when it is larger than 3, the behavior of these corrections is quite different. in the case of a ratio @x maths4 > 3,   the behavior can be explained by the fact that the ratios of the two terms in the asymptotic expansion are related to the so - called kronecker s double series which are directly related to elliptic theta functions.
@xmath0-ray astronomy provides insight to understanding the non thermal processes in sources that undergo the most violent phenomena in the universe, such as active galactic nuclei ( agn ), gamma - ray bursts ( grb ) and pulsars.   the two dominant contributions to the photon angular resolution are, on the one hand, the single track angular resolution of the two leptons, and on the other hand the impossibility to measure the momentum of the recoiling ion. with the low - density detectors presently under development, the track directions can be measured with enough precision before multiple scattering ruins the azimuthal information carried by the pair  . however, the missing recoil momentum is the main contributor to the weak degradation of the angular resolution due to the not measured recoil momentum. in the present paper   we reconsider the angular resolved due to this problem with the new exact 5d event generator described in  @xcite, without any approximation in the calculation of theangular resolution, extending the study to the lowest energies, very close to threshold, and providing 68%, 95% and 99.7% quantiles of the squared angular resolution.    we then characterise the behaviour of other available event generators
we present a methodology for determining the resonant forcing of a system of first order differential equations in which only select degrees of freedom are forced.   we show that the optimal forcing function induces a desired response more efficiently than a sinusoidal forcing function for a nonlinear oscillator driven with the correct aperiodic signal, and that certain lagrange multipliers play a fundamental physical role in the efficiency of the forcing function.
we have recently discovered three new binary pulsars in the mid - latitude egret region of the sky at galactic latitudes @xmath11.4ghz.   we have used the 8-m gemini - south optical telescope to observe the pulsar and its two companion stars with a range of wavelengths from 1.4 to 1350mhz. using the parkes telescope and the multibeam receiver, we have measured the timing of the pulsations of the three new binaries using the x - ray spectroscopy instrument on the geodesic arm of the 8 m gemini South optical telescope ( gbt ). for the first time we have also measured the spin - down rate of the main pulse of one of the systems.
spin transfer torques are the effects of spin - based interactions between ferromagnetic elements and electrons.   the goal of this article is to provide an introduction to the topical scientific issues concerning the theories, experiments, and commercial applications related to these effects. in the first article  , we provide a brief history of the field and provide references to background material. in section , we introduce aspects of ferromagnetism that are important to the discussion, particularly for transition - metal ferromagnets, and discuss how spin polarized currents arise. in sections  and [ sec:(1 ) stt describes how spin transfer torque can be understood as resulting from changes in spin currents. in each section,   we discuss the current state of research on spin - transfer - induced domain wall motion in magnetic nanostructures. by means of these studies, we show that the giant magnetoresistance ( gmr ) effect can be explained as a result of the change in the relative orientation of the magnetizations of two ferrommagnetic layers separated by an external magnetic field. by contrast, by using the multi - layer exchange coupling ( multi ) theory, we
the atmosphere of titan s ligeia mare is dominated by methane and ethane, which are expected to accumulate in the surface liquids and thus be important constituents of liquid bodies that are in equilibrium with the atmosphere.   this classical picture, derived from titan s photochemistry models, contrasts with the indirect measurements of the composition of the sea on titan s surface, which suggest that this sea is predominantly methane - dominated. here  , we investigate the range of initial compositions of the hydrocarbon lakes and seas present on titan using the model proposed by mousis et al. ( 2014 ) to investigate the effects of interactions with clathrate reservoirs that progressively form if the liquid mixtures diffuse throughout preexisting porous icy layers.. we demonstrate that a sea will become methane - dominant for any initial ethane mole fraction below 0.75 if it interacts with an underlying clathration layer that progressively formed from the entrapment of methane andethane.
the trace anomaly or the conformal anomaly is a non - vanishing trace of the renormalised stress - energy tensor in quantum field theory.   it has been argued that the trace anomaly could potentially provide us with a dynamical explanation of the cosmological constant problem. in this contribution  , we argue in favour of a semiclassical approach to examining the connection between the cosmsological constant and the trace anomalies. by taking expectation values of inhomogeneous quantum fluctuations with respect to a certain state to study its effect on the background spacetime, we show that the conformation of the metric tensor is not invariant under conformal transformations of the relativistic metric ; instead, it is variably coupled to a new conformal degree of freedom ( @xmath3\overline{g}_{\mu\nu}(x)$ ).    furthermore, we find that the effects of these fluctuations are small at the largest scales, comparable to the hubble radius ( and expected to be small also in the early universe).this paper aims at summarising the main results of @xcite, as presented at the " invisible universe conference" in paris ( 2009 ).
the variable kondo effect in a two - impurity kondo model ( tikm ) of condensed matter systems is investigated from the quantum entanglement perspective.   the influence of the rkky interaction and the antiferromagnetic ( afm ) kondo coupling on the observed kondo signature is discussed.    the experimental results show that the variation of kondo effects and its competition with magnetic order in the kondo lattice systems may result in a local type of quantum phase transition signaled by a breakdown of konda effect.
dark matter ( dm ) is a major research theme in both particle physics and astrophysics.   the recent study @xcite has provided conservative limits on the dm cross - section of the diffuse galactic @xmath1-ray emission from the first 21 months of the fermi gamma - ray satellite, which is believed to be produced by interactions between cosmic rays and the interstellar medium. here  , we review the results of the analysis of the data using the navarro - frenk - white ( nfw ) profile for modeling pure dm and a cored profile for models of the baryonic matter effect that cover the possible mass range over which dm is produced thermally in the early universe.    we also discuss the implications of these results for the interpretation of the pamela/fermi - lat cosmic ray anomalies.
we present a new theory of the discrete centroaffine indifinite surface, which is concerned with some invariant properties of this type of surface.   it is organized as follows : ( 1 ) we define the discrete centre of the continuum in euclidean 3-space and then obtain the structure equations, compatibility conditions and some centro affine invariants for the surface ; ( 2 ) the laplacian operator is defined as the gradient of the dirichlet energy for the degenerate form of the infinite surface with constant coefficients ; ( 3 ) the convexity of the surface is considered ; ( 4 ) the congruence between the space of points and the tangent space at each point of the curve is obtained ; ( 5 ) the convergence of the curvature to the fourth power of the distance of the tangenter plane from the origin is invariant ; ( 6 ) the concaveness of the surfaces is studied ; ( 7 ) the density of the curves is calculated ; ( 8 ) the area integral of the transformation group is computed ; ( 9 ) the polynomials of the local basis of the differential transform are obtained ; and ( 10 ) the geometries of the
the @xmath2 absorber previously detected with @xcite in the far - uv of the low-@xmath25 universe has been used as a probe of the warm - hot intergalactic medium ( whim ) gas in the extended halos of galaxies.   the detection of the presence of collisionally ionized warm gas in this absorber is important because it can be used to determine the temperature of the gas and its metallicity. here   we report the results of a new study of the cosmic origins spectrograph ( cos ) spectroscopy of the absorption of warm gas with @x Math2 at ~1.5  kev in the near - ultraviolet ( fuv ) spectrum of the @x maths2 absorbber.    the absorption line spectra are consistent with the observation of collisional ionization of the gaseous envelope of the absorber by photoionized gas, but the relatively few lines covered in the x - ray absorption data were inadequate to constrain the ionization conditions and metallivity of the heat - heated gas. for the first time, the cos spectroscopic features of the observed warm gas have been compared with those of the
line driving is the most commonly used mechanism to explain the mass loss of massive, hot stars.   however, some stars, most notably luminous blue variable stars ( lbvs ) such as @xmath0  carinae, experience outbursts with mass loss rates several orders of magnitude higher than can be explained through line driving. in the case of @x Math0   carinai, the 1840 s outburst was accompanied by a strong increase in radiative luminosity, very likely making it well above the eddington limit for which continuum driving by just electron scattering would exceed the stellar gravity. here   we discuss the possibility that this extended increase in luminosity is due to continuum driving, which results in a sustained mass loss that greatly exceeds what is possible through line opacity.
the calculation of higher - order corrections of the standard model of high - energy - physics is one of the most important problems in quantum mechanics.   the complexity of such calculations and the final results strongly increases with the number of quantum loops considered, and one rapidly reaches the limits of the present realm of possibility when one attempts to exactly account for all mass scales of a given problem, already at the two - loop level. to simplify the calculations and also the final expressions, various types of expansions were proposed during the last couple of years. here  , we introduce a new approach to the calculation of tadpoles and loops with massless propagators, defined in eqs. ( {$\scriptstyle\alpha_1 $ }    \text(38,18){\displaystyle \alpha_2-d/2 } }, \label{eq : one}{(k^2+m^2)^\alpha}=\hspace{3 mm } \mbox { { \begin{picture}(70,30)(0,4 ) \gluon(5,5)(65,5){1}{6 } \ver
reversible logic is a powerful tool for realizing reversible boolean functions in quantum computing.   it can be used to achieve theoretically zero power dissipation  @xcite in physical reversible computing, and several target technologies in nanoscale computing as well as technologies beyond cmos, in particular quantum computing, also rely on reversible logic. the problem of reversible logic synthesis is to map a given reversible boolean function on a reversible logic gate library. here  , we present a comprehensive review of the state - of - the - art reversible logic syntheses using quantum cost ( qc ) assumption of quantum reversible computing.
we show that the presence of broad line regions ( bls ) in seyfert 2 galaxies is regulated by the ratio between the x - ray luminosity and the eddington luminosity, which, in the accretion  power scenario, is a measure of the rate at which matter accretes onto the central supermassive black hole.   the model proposed by nicastro ( 2000 ) suggests that the bls are formed by accretion disk instabilities occurring in close proximity to the critical radius at which the disk changes from gas pressure dominated to radiation pressure dominated. for low enough accretion rates ( and therefore luminosities )  , the critical diameter of the disk becomes smaller than the innermost stable orbit, and bls can not form.
the volume fraction of disordered packing of grains is estimated to be @xmath14.   this value is the smallest volume fraction attainable letting the particle sediment under gravity, and is also the lower bound for the volume fraction at which jammed packings are found in the limit of zero sedimentation velocity when particles fall in a very high viscous fluid. here   we give evidence that, at zero friction, @x math14 is the upper limit of the volume fractions of grain packings obtained by different research groups using different algorithms to prepare jamming packings of frictionless particles.
we have used microscopic many - body self consistent model based on deformed hartree - fock procedure and subsequent angular momentum projection technique for a reliable description of the nuclear structure of some medium as well heavy nuclei participating in double beta decay processes in the mass range @xmath0 to@xmath6.   the results show that the proposed model is able to reproduce the observed low - lying spectroscopic properties of the nuclei with good agreement with the experimental data.
fk comae berenices ( ) is a rapidly rotating and apparently single g5 ii giant.   it has a rotational velocity of 162.5  @xmath5  3.0  km  s@xmath6 and a radial velocity of -24  @Xmath 5  3 km  s/s@x Math6. in the past, two scenarios have been proposed to explain the observed rotational and activity characteristics : accretion from a very small unseen companion or product of the recent coalescence of a close binary system. here   we present a model of the evolution of this star based on the analysis of the spectrum of the h@x math0  emission line. using the x - ray spectra of the star as a reference, we show that the emission arises in structures similar to solar prominences, with the emission lines corotating with the star during the early stages of the transition phase. at the same time, the rotation rate is fast and the radial velocity is near breakup.    the main component of the emission line is a strong uv chromospheric emission line, which is broad, asymmetric and presents variations on different time scales.
nuclear spirals are known to be preponderant in active galaxies.   the response of gaseous disk to the imposed non - axisymmetric potentials depends not only on the potential shape of the model galaxy but also on the hydrodynamic properties of the gasesous disk. here  , we present some results of numerical experiments including smbh for the formation of nuclear spirals, based on smoothed particle hydrodynamics ( sph ). a barred galaxy is assumed to be made up of three stellar components ( bulge, disk, bar ) and two dark ones ( smbh, halo ) which are separated by a distance of about 10 km / s from the interstellar medium ( iilr ). as shown clearly in the simulations, the nuclear regions of the Gaseous disks of models with no smbh evolve to leading spirals between the Iilr and oilr, whereas those with smbh develop trailing spirals whose detailed shapes depend on the sound speeds in the gas.
a numerical approach is presented to the full time - dependent schrdinger equation of two interacting atoms in a single - well or multiple - well optical lattice.   the hamiltonian of the system is solved by using the stationary solutions of the lattice potential obtained by a procedure presented in @xcite, which allows for the manipulation of any additional perturbation up to quadratic order ( e.g., an acceleration of the optical lattices or a periodic driving ).    the results of the time propagation are validated by a comparison to problems that possess an analytical solution.
we present a social force model of crowd dynamics in a two - dimensional, triangular lattice.   we use the imitation effect to simulate the behaviour of pedestrians in a crowd and to investigate the influence of their behaviour on the formation of a local crowd structure. using this model, we find that there is a phase transition between the ordered and the disordered phase of the crowd structure, which is visible by means of the fluctuation function @xcite. during the simulation,   pedestrians change their strategies with some probabilities @xmath4, that depend on the number of neighbouring subjects currently using the same strategy ( i.e., the number six out of 6 direct neighbours of a given pedestrian).the phase transition is shown to be visible in the results of our field observations of crowd.
the emergence of cooperation among selfish individuals is an intensively studied problem in the game theoretical models of the public goods game ( pgg ).   however, several mechanisms for the evolution of cooperation in the pgg have been proposed, such as punishment, reward, reputation, network reciprocity, social diversity, and success - driven distribution. here  , we propose a coevolutionary rule to study the coemergence of cooperation by means of the adaptive multiplication factor that evolves based on the local strategy distributions in the group and the global strategy distribution in the whole system. within this rule,   the multiplication factor is used to measure the local interacting environment in each group, rather than individual s feature or the entire system s interaction conditions. also, the feedback return of the local investment to the public good is measured, and a larger value of the multiplicative factor enables a better investment return. from the perspective of the complex interaction networks, it is found that the complexity of the system can be explained by the existence of inhomogeneities and social diversity about features of the model, e.g., individual social ties, noise level, payoff matrices, capability of strategy transfer, and individual learning rules
magnetic reconnection is a process in which magnetic energy is converted into kinetic energy as the topology of the magnetic field changes.   this process can produce fast energy transfer and accelerate particles to high energies, which may be used to produce observed high - energy emission in various astrophysical contexts such as the prompt phase of gamma - ray bursts ( grbs ) and pulsar wind nebulae in the active galactic nucleus ( agn ) jets. here   we investigate the possibility that magnetic reconnection can produce synchrotron radiation beyond the maximum burnoff limit of 160 mev in a system of harris - like magnetic reconnections where the acceleration of the particles is primarily perpendicular to the reversing field. using a combination of theoretical and experimental data, we show that the acceleration rate of the accelerating particles is not limited by cooling in the magnetic reconnectional region of the system, but that it can be decoupled from the cooling process in the diffusion region. for the magnetization @xmath0/1 ratio of the electron mass, the speed of light, the fine - structure constant, and the lorentz factor of the particle, it is possible to accelerate the particles to energies up to 1 gev
abstractfor a galactic or near - extragalactic core - collapse supernova, neutrinos offer the unique possibility of directly observing the dynamics and thermodynamic conditions prevalent in the supernova core.   they are expected to be the first to detect the next nearby supernova and will herald it before any telescope sensitive to electromagnetic waves will notice the event. together with gravitational waves,   these observations will allow us to probe in detail a broad range of supernova astrophysics, nuclear physics, and neutrino physics.
the binary fraction is an essential component in the formation and evolution of dynamically active systems, like globular clusters ( gcs ).   it is also crucial for understanding the properties of puzzling objects like blue stragglers, millisecond pulsars and cataclysmic variables, which are all thought to be the by - products of binary evolution. despite its implications, however, the binary fraction in gcs still remains badly constrained, because of the challenging observational requirements. here  , we present a new method for estimating the fraction of binary systems in a sample of gcs, based on the analysis of the radial distribution of main - sequence stars in color - magnitude diagrams ( cmds ). using this method, we show that the observed rising branch of the distribution can be explained by a non - negligible fraction of primordial binaries, which still orbit in isolation in the cluster outskirts and produce the observed rise branch of their distribution. since the flux of unresolved binaries is equal to the sum of the fluxes of the two components, the binaries composed by main - sequences companions are shifted towards brighter magnitudes with respect to the single - star ms. as a result,   the ratio of unresolved to unresolved binaries in the cmds is
the electroweak sector is the last piece of the standard model that needs to be confirmed.   this is one of the main analyses which are going to be performed by the lhc and the ilc. in this article   we will focus on measurements of the quantity @xmath12 which parametrizes cpt violation in the top sector.
the interaction between the wcr of two long - period wolf - rayet binaries, wr140 and v444  cyg, is studied by comparing the observed x - ray flux arising from the Wcr to predictions from hydrodynamical models of this interaction @xcite.   the results show that the interaction is highly structured, with a high degree of structure, or " clumping ", in the wind of order ( wcr ) which is rapidly smoothed out as the wind becomes more clumpy. for wr140,   most of the mass - loss rates are sensitive to the square of the density, but the rate of mass loss is reduced by a factor of 3 or more if the wind is more structured.. the effects of these changes on the interaction region are discussed.
the field of ultracold atomic gases has progressed rapidly over the last decades.   this progress was driven by the ability to continuously discover and control new features of these systems, such as the long - range and anisotropic character of the dipole - dipole interaction, which goes beyond the properties of contact potentials. here   we investigate quadrupole - quadrupoles interactions as a novel feature of ultracellular atom systems. for alkaline - earth atoms such as yb and sr in any@xmath5 state of the @xmath6 manifold, prepared in an optical lattice with a lattice constant of a few hundreds of nanometers, we propose to measure the mean - field shift of a mott state in a 2d optical square lattice as a function of the angles @x maths1 and @x math2.. for comparison, we study a quasi-2d fermi gas of spin - polarized atoms in continuum, for which we find a characteristic angular dependence of the induced mean - fields that changes from repulsive to attractive and back within the range of @x Math12. using ultra - high precision spectroscopy  , we show that the
the current work is based on the idea that macroscopic properties of dense materials result from major dynamical properties of structural rearrangement of the contact network.   the main focus of this work is on the so - called kohlrausch - williams - watts ( kww ) relaxation in granular materials, which is a time - logarithmic relaxation of the occupied volume, in strong analogy with free - volume relaxation, commonly observed in glasses, and of central importance for aging.    the effects of free - volumes on the kww relaxation are also discussed.. the theoretical arguments underlying these equations are elaborated, and the consequences of their consequences are discussed.
the detection of hydrogen- and volatile - rich exoplanets at orbital distances @xmath01 au opens questions regarding their upper atmosphere structures and the stability against escape of atmospheric gases.   the first observational evidence of an xuv - heated extended non - hydrostatic upper atmosphere was obtained for the hot gas giant hd 209458b, which orbits a sun - like star at 0.047 au. in this study, we investigate the presence of heavy elements around the roche lobe of the highly irradiated " hot jupiter " wasp-12b, an inflated gas giant at @x Math50.023 au, using a combination of spectroscopic and computational techniques.    the results show that the observed heavy isotope enrichment in the atmosphere of hd209458b is caused by a population of atomic hydrogen located beyond the roChe lobe, which is likely to have been dragged there by the upward - flowing neutral gas from the planet s solar system. as most of the detected heavy elements can only be dragged to the upper atmosphere regions along with upward flowing hydrogen atoms,   these observations confirm scenarios which were suggested by sekiya, nakazawa, & hayashi ( 1980 ), seki
luca marinatto and tullio weber@xcite have proposed a scheme to quantize the famous _ battle of the sexes game_.   they give an hilbert structure to the strategic spaces of the players, so allowing the existence of linear combinations of classical strategies to be interpreted according to usual formalism of orthodox quantum mechanics. in their work,   the authors show that if both players are allowed to play entangled quantum strategies, the game has a unique solution. however, benjamin pointed out that the players are still subject to a dilemma.
the spectral lines of the he i 10830   and d@xmath0 multiplet at 5876  are of great diagnostic value for investigating the dynamic and magnetic properties of plasma structures in the solar chromosphere and corona.   their polarization is sensitive to the presence of atomic level polarization and to the joint action of the hanle and zeeman effects, which makes these lines especially sensitive to strong fields found in solar active regions and also to the weaker fields encountered in a variety of plasma structure such as filaments, regions of emerging magnetic flux, chromospheric spicules and prominences. in order to be able to obtain reliable inferences from the observed spectral line radiation it is necessary to reach a rigorous physical understanding of the key mechanisms that are responsible for its intensity and polarization. in this paper   we show that the mechanism of collisional excitation at temperatures greater than 20000 k seems to require ( or is helped by ) the existence of a temperature  plateau " located in the lower transition region ( tr ) of the sun, such that the euv radiation irradiating the chromosphere ionizes part of the substantial amount of neutral helium atoms that are found in the ground singlet state at the
4u  170544 is a neutron - star low - mass x - ray binary ( lmxb ) classified as an atoll source.   it shows spectral variability on all time scales, from months down to milliseconds. in this paper  , we present results of a study of the spectral variability of 4u 170544 during state transitions observed recently by _ integral_/ibis during its monitoring of the galactic centre region, and earlier by _ bepposax. using data from the same detector, we show that the emission line at @xmath0 kev is intrinsically broad ( fwhm@xmath11.2 kev ), consistent with the observation of similar broad emission lines at energies in the range of 6.46.7 kev in the spectra of lmxbs, both in systems containing black holes @xcite and old neutron stars @xaite.    the spectrum of compton reflection of x - rays has a characteristic shape resulting from photoelectric absorption at low energies and compton scattering ( including its recoil ) at higher energies, with a broad hump around 30 kev. for the first time,   such a component has never been reported for 4
the absolute scale of the neutrino mass remains unknown.   the katrin experiment is currently pursuing a new generation of tritium endpoint measurements, which are expected to be as low as @xmath3  ev. here   we propose a new approach to the measurement of the neutron mass based on the recent development of general methods for trapping and cooling of paramagnetic atoms or molecules using pulsed electromagnetic coils and single - photon cooling. in order to achieve this, we need a spectrometer to measure the@xmath0 energy and a non - invasive technique for measuring two components of its momentum. by utilizing the coincidence between the @x Math0 and the helium ion, we can determine the four - momenta of the ions ( @x math6 ) and the @Xmath0 ( @ xmath7 ) and divide the kinetic energy by the three momentum components of the #xmath1-decay to obtain the total neutrinosummonic mass.    we present detailed simulation results and the detector requirements necessary to reach sub - ev sensitivity on the neut rino mass.
the nuclear level density and @xmath0-ray strength function of the n+@xmath2pu compound system are extracted from the neutron capture cross section of @x Math1pu using the oslo method.   the measured level density is used as an input for hauser - feshbach calculations of the @x math2pu@x maths14 cross section.    the obtained level density values are compared to an estimated @xMath0-raysf, and the experimental scissors resonance ( sr ) is interpreted as an enhancement of the calculated @x mathematics0- ray strength function. in order to estimate the rate of neutron capture reaction rates for the //- ratio, the level density was normalized to the constant - temperature level density formula and the observed sr was used as a parameter for the calculation of the kinetic energy of the r = 0.15  kj / cm2 at room temperature. conclusionsthe results show that the sr can be used to improve the accuracy of the model calculations based on the measured data.
the dimensionless spin parameter @xmath4 of the black hole formed by the coalescence of a black - hole binary is a complicated function of the initial masses and spins of the two constituent black holes.   the first estimate of @x Math4 was made in 2000, on the basis of a new analytical approach to the general relativistic two - body dynamics, the _ effective - one - body _ ( eob ) approach, and was revised downwards in 2002, when a better way of bridging the far- and close - limit approaches indicated that the angular momentum losses were larger than previously estimated. here   we update the analytical eob estimates using the now available 3.5 post - newtonian ( pn ) accurate description of the dynamics, and show that increasing the pn accuracy of the simulations down to 3. 5pn has the effect of decreasing the final spin parameter from@xmath7 to @x math17 ( i.e. for the equal mass case ), and again for the ringing final black hole.
the existence of persistent current in a single - channel metallic ring threaded by an aharonov - bohm ( ab ) flux is a direct consequence of quantum phase coherence.   we have measured the magnetic response of individual cold mesoscopic gold rings, one ring at a time, using a scanning squid technique and find that the measured current amplitude agrees quite well with theory in both the isolated single ballistic ring and an ensemble of nearly ballistic gaas - algaas rings. however, the results of the single loop experiments are significantly different from those for the ensemble of isolated loops.
we report measurements of extinction of light from field stars in the coma of comet 17p / holmes ( hereafter, 17p ) during an explosion in 2007.   we used a 2.2-m telescope with a charged coupled device to measure the brightness of field stars at 1 s integration times of 1 s and 120 s for the narrowband blue continuum ( bc ), red continuum ( rc ) and red continuum filters @xmath19, 20, 21 and 22. using these filters, we found that within our region of interest there was a sharp extinction of about 10% of the visible light from the field stars when the comet was at peak brightness, which is consistent with the extinction reported by @xcite but is much deeper than the extinction measured by surface photometry at much larger angular distances from the nucleus ( 25 to 180 arcsec ) where surface photometric data indicate immeasurably low line of sight optical depths.
we study the polarization survey results of bl lacertae made at 15 ghz with the vlba, under the mojave program.   we find that the polarization of the jet is strongly correlated with the electric vector position angle ( evpa ) of the magnetic field vector b in the beam frame, and that the transvese disturbances are caused by a series of alfvn waves propagating along the longitudinal component of the field. this behavior is highly similar to the results of numerical modeling of @xcite, in which the jet has a helical magnetic field that dominates the dynamics, and is in the form of a helix with a high pitch angle.
in 1939, wigner introduced the lorentz group to physics. in this paper, he introduced his " little groups " and provided the framework for studying the internal space - time symmetries of relativistic particles.   the scientific contents of this paper have not yet been fully recognized by the physics community. here  , we report on the current state of the art in classical ray optics, which is largely formulated in terms of two - by - two matrices. a mathematical language based on two - By - Two matrices   can serve as the scientific language for several different branches of physics, including special relativity, quantum optics, and quantum optics.
we examine the problem of a mixture of different mass fermionic atoms on an optical lattice at low temperature.   we have already performed numerical calculations on this system and shown that one can see interesting phenomena similar to viscous fingering as one tunes the trap curvature for the light species and moves from a phase separated state with the heavies on the outside to one with the heavy atoms on the inside  . however, how do we detect the presence of such order with current experimentally available techniques? in situations where  in situ  imaging with single - site precision is available  , one would simply look for the ordered phases directly, just as they appear in the monte carlo snapshots of a particular configuration of the atoms. but can one see effects of the density - wave ordering in a time - of - flight image, or via direct bragg scattering of light off of the dense density - waves pattern?   here we answer these questions using the falicov  kimball hamiltonian (  model ) and numerical methods.
the renormalization group ( rg ) theory of the second order transition between he i and he ii is the basis of the experiment of the heat capacity exponent, @xmath12, measured in a space experiment conducted in 1992 @xcite, which is one of the core tests of the theory.   we have now performed a more detailed analysis of this experiment with the aim of reducing systematic bias in the results as much as possible. for the ratio a@xmath2/a@x Math3, we have found better agreement with the predictions than previously. for some other quantities, such as the temperature of the specific heat of sf@x math9, we find that the experimental results are consistent with the most recent predictions.
the renormalizability of the effective lagrangian advocated in @xcite for a massive gluon theory - field with a global gauge group @xmath4 symmetry is investigated.   the renormalization of the gauge field is achieved by removing all physical higgs particles from the theory and replacing them with nonabelian vector mesons with a frozen radial degree of freedom, which are then absorbed into the redefinition of the unitary gauge. to clarify the significance of this model as an effective low energy theory, it is shown that the confinement property of the higgs phase can be shown to satisfy a perimeter law for the wilson loop in the fundamental representation.
we investigate the impact of the efficient provision of cold gas at high redshift on the evolution and formation of galaxies.   we use the semi - analytic model _ simurgh  to model the formation and evolution of galaxies in a dark matter halo with a mass resolution of @xmath7. using this model, we show that the accretion of hot gas into the host halos virial temperature is fast and efficient, and that the rate of accretion is comparable to the dark matter accretion rate times the cosmological baryon fraction. during this process,   all the cold gas in the progenitor disks will be consumed in a central starburst, adding to the spheroid mass, and all stars in the galaxy progenitors will contribute to the proton mass of the protons in the center of the progenic disk. by the time of the first starburst  , a large fraction of the stellar mass of massive galaxies has already been accreted into the core of the halo, which is then collapsed into a rotationally supported disk of initial hot gas at the halosvirial temperature, followed by star formation in this disk where the main mechanism to build
the pegasus ( ddo216 ) dwarf galaxy is an isolated, transition - type dwarf satellite of a large galaxy.   it is thought that it may be ram pressure stripped of some of its gaseous component in a hot halo of the milky way or m31. here  , we show that this is not the case. using photometry from the 2.5meter isaac newton telescope on the night of 8 august 2003, we have measured the distances of the stars and the gas density of the outermost regions of the dwarf galaxy. to our knowledge, this is the first direct evidence for hot gas associated with the local group.
abstractthe interferometric visibility of the pulsar b0329 + 54 with radioastron is resolved on baselines that fully resolve the interstellar scattering disk.   the visibility takes the form of random phase and amplitude variations that vary randomly with observing frequency and time. in the fourier - conjugate domain of delay and fringe rate, the visibility forms a localized, extended region around the origin, composed of many random spikes. using averages and correlation functions,   we argue theoretically that its extent in delay is given by the average envelope of the impulse - response function of interstellar scattering, sometimes called the pulse - broadening function.we find that the observed distribution is well - fit by a model that is derived from an impulse - reaction function that has two different exponential scales.    we discuss possible origins of the two scales.
active galactic nuclei ( agns ) are often believed to play a significant role in galaxy evolution.   however, the nature of agn feedback and the coupling of the agn energy output with the interstellar matter ( ism ) is a subject of active research in this field. by connecting nuclear activity with the larger scale ism and star formation ( sf ), agn outflows may push gas out of host galaxies and/or heat up the ism, leading to suppression of sf @xcite. on the other hand, out flows may trigger sf by compressing the ist. here  , we present a census of ionized gas outflows in agns based on the  @xmath05007 kinematics, by analyzing a sample of 39,000 present - day type 2 agns from sloan digital sky survey ( sdss ) over the full luminosity range explored in the first paper. for typical agns,   at least 50% of agns show kinematic signatures of gas outflow, indicating an average scaling between agn activity and sf across galaxy scales ; however, at high redshift, agns tend to show enhanced sf.
the nambu - jona - lasinio ( njl ) model of quantum field theory is known to be non - renormalizable in the large @xmath0 limit.   however, it is renormalizable in the @x math1 perturbation theory. at finite temperature, the effective potential of the njl model develops an imaginary part which complicates the analysis of the symmetry breaking and restoration. in this paper  , we study the effects of the fluctuations of the composite scalar particles on the next to leading order effective potentials for the three - dimensional model at zero and finite temperatures. by using the hubbard - stratonovich transformation, we show that the global minimum of the potential does indeed occur at the origin or, in other words, that the symmetry is not broken at any finite temperature. when the fluctuations are included in the calculations, the results are in good agreement with the mermin - wagner - coleman theorem.
we have determined the mid - ir fluxes and magnitudes of nine white dwarfs in the hyades ( hz4, lb227, vr7,vr16, hz7, hZ14, lp475 - 242 ) around two different roll angles separated by 20 degrees through the f110w and f160w filters of the hst / nicmos pipeline.   the results show that the mean fluxes of the targets are 310 m@xmath8 with a mean temperature of 1.5 kj / cm2 and a mean mass of 2.1 jupiter masses.
plasmonic materials ( most notably metals ) suffer from large losses in the frequency regimes of interest, which resulted in a wide search for better materials.   lots of attention has recently been given to plasmonics in graphene, which is a single two - dimensional ( 2d ) plane of carbon atoms arranged in a honeycomb lattice @xcite. however, it is still not clear how the scattering rates change with frequency, particularly in the infrared ( ir ) region. in this paper  , we focus on optical absorption mediated by charged impurity scattering in graphene and show that the experimental results are much larger than the estimate based on density functional theory ( dc ) transport measurements. at low frequency,   the observed absorption is almost two orders of magnitude lower than the measured value, while at high frequency, the experiment shows a strong increase of absorption even below the fermi energy threshold. here, we discuss the possible reasons for these differences.
the dephasing rate of the aharonov - bohm oscillations in a single - level quantum dot interferometer ( abi ) with a quantum point contact ( qpc ) located near the quantum dot is calculated.   the effect of the qpc on the dephased oscillations is investigated by means of the influence functional method and the master equation techniques. for the qd coupled to a conducting wpd the dehasing rate is given in terms of the voltage fluctuations in the conductance of the ring and the current flowing through the wpd. at a large bias the oscillations are reduced while at small bias they are not affected.
the energy conditions are assumptions made on the material content of the spacetime to extract generic characteristics of the geometry through the equations of the dynamics.   the main approach that has been developed in the literature consists in averaging those energy conditions along timelike or null curves, or in using some quantum inequalities to restrict the magnitude and duration of negative energies @xcite. here   we present a different approach, considering other pointwise energy conditions such as the flux energy condition ( fec ) which assumes that the energy density measured by any observer is non - negative and propagates in a causal way. for this condition,   it is possible to obtain entropy bounds for uncollapsed systems, and for the boulware vacuum of a schwarzschild black hole, one can also obtain bounds for the unruh vacua. since the fec is a consequence of the strong energy condition, we show that the bounded violations of the fec are much larger than those of the weak energy condition when the matter content is considered as a function of the einstein equation. moreover, we find that the brevity of the time - dependent decay of the fermi cosmological model is reduced by the use of quantum inequalities.
the large - scale magnetodydrodynamic ( mhd ) alfvn wave, which is generated by the magnetic stress tensor, is a nondispersive low frequency wave mode and can be directly derived from the mhd equations. in this paper, we investigate the nonlocal interaction among one mhd alfVn wave and two kinetic alFvn waves ( kaws ), and we show that the nonlinear coupling between the two waves may play an important role in generating the kaws with electron scales @xcite.   the local nonlinear decay among the two kaws can be explained by the resonant relation of the two wavenumbers of the three waves, which describes the phase relation of these three waves. for the two small - scale kaws,   it is found that the two counterpropagating waves can be nonlocally excited by the same mhdalfvns wave, and they can decay parametrically into two small- and three - wave kaws when their perpendicular wavelength is close to the order of the ion inertial length or the ion gyroradius in the solar wind turbulence ; however, the energy transfer from the larger - scale
we study adiabatic pumping through interacting quantum dots for temperatures much above the kondo temperature but much below the level spacing in the dot.   we use a diagrammatic real - time technique to describe non - equilibrium dc transport through an interacting quantum dot. as compared to the formalism in our recent work,   the perturbative approach presented here, although limited to weak tunnel - coupling strengths, is more transparent in identifying the physical origin of the various contributions to the pumped charge. in particular it is straightforward to relate the pumped current to the dynamics of the average charge of the quantum dot and to the leading- and next - to - leading - order contribution of the perturbed expansion in the tunnel coupling to the pump charge per pumping cycle. considering two cases : pumping by changing periodically either the gate voltage and one tunnel barrier or varying both left and right tunnel barriers, the adiabsidic pump works analogously to a peristaltic pump because the next - order correction turns out to be only due to a time - dependent renormalization of the dot - level position that is induced by the combination of coulomb interaction and tunnel coupled to the leads. remarkably this effect is not masked by other higher
the diphoton excess with an invariant mass around @xmath0gev was recently reported by the atlas @xcite and cms  @xcite collaborations.   we consider a possibility that the large hypercharges are originated from unbroken hidden u(1)@xmath10 gauge symmetry which has a relatively strong gauge coupling and a significant kinetic mixing with u ( 1)@Xmath1. in this model,   the ( pseudo)scalar coupled to gluons and photons through the extra quark / hidden fermion loop diagrams is produced via gluon fusion and decays into a pair of photons through one - loop diagrams with the extra Quarks / leptons running in the loop. since thehidden fermions are charged under u(2)@ xmath10, they acquire hypercharges through the kinetic mixing, and the induced hypercharge is cosmologically stable. such stable exotic charged particles, if produced abundantly in the early universe, could affect the big bang nucleosynthesis ( bbn ) as well as cosmic microwave back ground radiation ( cmb ).
in 1992, callan, giddings, harvey, and strominger ( cghs ) @xcite proposed a simplified framework for investigating black - hole formation and evaporation.   they introduced a two - dimensional toy - model with gravity and matter fields coupled to a dilaton scalar field. at the classical level  , this model admits a one - parameter family of static black -hole solutions. when semiclassical corrections are added, the two - dimension black hole emits thermal radiation and consequently evaporates. in this paper, we analyze the asymptotic behavior of the various fields at the singularity, and then match these solutions at their respective overlap regions. by constructing approximate solutions in various domains of the bh interior,   we obtain a family of local asymptic solutions which depend on certain free parameters ( or free functions, depending on the context ). using the value of the dilaton filed as a reference, we find that the values of the free parameters depend on the distance from the horizon to the single - particle singularity : the distance between the horizon and the singularities is the most important parameter, and the distance below it is the least important.graphical abstract
the description of magnetic ions in a semiconductor host material poses an interesting but difficult problem in theoretical condensed matter physics.   mn - doped ii - vi semiconductors have attracted a lot of attention with the perspective of using the spin degree of freedom for electronic devices ( ` spintronics'). here  , we show that the concept of interacting heisenberg spins remains applicable for mn ions diluted in ii - v semiconductor. by calculating the exchange couplings between nearest neighbors of mn-2 + ions at up to fourth neighbors in cd(mn)te, zn(mn]te, Zn(mns)se, and zns, we confirm that the interaction between mn+ ions and their neighboring wannier orbitals is mediated by antiferromagnetic pair couplings @xmath2 and find a reasonable agreement with measured values for the corresponding values for cd@xmath11mn@x Math12te, xmn=2.0, ymn=3.0,xmn=4.0 as well as for zn<2.5, xmr=1.5,xmr=0.5
we provide a comprehensive account of the basic theory of the tits cone and the coxeter complex of a weyl groupoid.   we introduce the notion of a root system of a tits arrangement on a convex open cone and give two canonical procedures to produce simplicial arrangements of smaller rank. given a simplicial arrangement of rank @xmath8 on an open convex cone, one can associate it with a gated chamber complex which is of natural type and has a natural type function. in the case of a thin chamber complex,   the same procedure is also used to obtain a simpler version of the same result.
we investigate the transport coefficient for mobility of a projectile in a strongly coupled plasma, in which the potential energy exceeds the kinetic energy, so that particles self - organize into a liquid - like or solid - like structure.   we find that the mobility of the projectile is influenced by two types of collisions : coulomb collisions among strongly coupled dust particles and friction due to collisions of gas atoms with the projectile.    the latter is modeled as a simple drag term, which does not require a particle description of the gas atoms.. the former is modeled by a yukawa potential, which is used to describe the friction between the projectile and the ambient neutral gas.
the sloan digital sky survey ( sdss ; @xcite ) is producing imaging and spectroscopic surveys over @xmath8 steradians in the northern galactic cap.   we present here a study of the number density and luminosity density distributions of galaxy colors, profiles, luminosities, surface brightnesses, and local densities. to date, the sdss has created the largest sample to date ( 144,609 galaxies ) of luminous galaxies with well - measured photometric and spectrophotometric properties. as a first step in understanding the joint distribution of galaxy properties, we show that the properties of galaxies with nearly exponential radial profiles are more likely to be found in dense regions of the sky than those with more concentrated radial profiles. using a simple fit of the results of our study, we find that the distribution of these properties is most strongly correlated with the luminosity of the galaxy.    the results also show that there is a strong dependence on luminosity on the density of the radial profiles of the galaxies studied.
dwarf galaxies are the most common type of galaxy in the universe and are thought to be the progenitors of larger structures.   however, the chemical evolution of dwarf spheroidal ( dsph ) galaxies has not been well studied. here   we show that the @xmath2-element ratios of the current sagittarius dsphy galaxies are significantly lower than those of the milky way globular clusters, suggesting that they have evolved from objects that had more rapid and therefore more core collapse supernovae - dominated chemical evolution over a hubble time ago. by contrast, the galactic halo is composed of objects that formed in a single burst, which suggests that the stars the sagittarias ds ph are contributing to the halo differ from those in the residual core. since the early universe was dominated by massive stars, it is likely that only core collapsesupernovae ( type ii snii ) were able to enrich the primordial interstellar medium with both fe and @x Math2-elements before the globular cluster formed. while their earliest populations were formed in the aftermath of the first snii events, their later populations benefited from ongoing snia, resulting in a
the world wide web ( web ) has tremendously influenced our lives by changing the way we manage and share the information.   today, we are not only static observers and receivers of information, but in turn, we actively change the information content and/or generate new pieces of information. in this way  , the entire community becomes a writer, in addition to being a reader. since the palette of human emotions is so vast and it is hard to select even the basic ones, most of the authors in the nlp community work with representation of sentiments according to their polarity, which means positive or negative evaluation of the meaning of the expressed opinion. here, we propose a novel approach to sentiment analysis based on the bag - of - features method proposed by @xcite. using this method, we classify opinions in subjective posts as falling under one of the two categories i.e., positive ornegative.    the performance achieved using the different feature representation, classifiers and other text processing techniques is compared.,the results show that the proposed approach is more efficient than the current methods used in machine learning.
this work investigates the notion of security index for dynamical systems under both attacks and disturbances.   in particular, we consider the case where attacks are said to be undetectable if they can be masked ( explained ) by a disturbance signal. as a result, we investigate the detectability conditions of sparse attacks that may be masked by plausible disturbances, and connect the results to fundamental limitations well - known in the control - theoretic literature, in terms of fault detection and identification and input reconstruction, in order to develop an effective cyber security strategy for networked control systems.
the detection of the transient gravitational - wave signals gw150914 and gw151226 during the first observing run of the two advanced ligo interferometers  @xcite has marked the start of gravitational wave astronomy.   the data analysis of these signals has been greatly improved by the development of new data analysis techniques, which combine post - newtonian methods with numerical relativity and perturbation theory to generate template banks for the effective - one - body formalism ( eob ) model of compact binary coalescence ( cbc ) using the ligo detector.    the most important step in this process is the identification of spurious noise signals ( glitches ), which can be identified by comparing the signal - to - noise ratio ( snr ) of the detected signals with the snr of the corresponding waveform templates from general relativity.. the second observing run ( o2 ) of both detectors is expected to start in late 2016 with a significant strain improvement. at the same time, the commissioning of the european detector advanced virgo   @xaite is well underway, aiming to start observing in the second half of this year, while the japanese detector kagra is
the formation of molecular hydrogen ( h@xmath0 ) in the interstellar medium ( ism ) by gas - grain reactions is one of the most important processes in star formation.   the interplay of dense molecular clouds with the cold neutral medium ( cnm ) allows for the formation of this molecule, which is generally regarded as amorphous in structure @xcite. here  , we present a new method for calculating the sticking probability of h@Xmath0 on the icy surface of the cnm using a combination of experimental and computational techniques.. the method is based on the calculation of the sticking coefficient, a quantity characterizing the probability that a given gas molecule sticks to a given substrate when it collides with an impinging atom on the surface of an icy grain.    the sticking coefficients are obtained by averaging the temperature of the gas molecules and the incident kinetic energy of the collisioning species at the grain surface. from the thermodynamic properties of the adsorbed gas molecules,   these quantities are used to calculate the number of collisions and the sticking probabilities of the two interacting species. according to the proposed method, the results show that the rate of sticking is proportional to the amount of time
the possible existence of dark matter ( dm ) is one of the most intriguing aspects of modern particle physics, astrophysics and cosmology.   a number of observations and experiments have been conducted or are underway around the world to survey the nature of dm, but the results are in strong tension with the constraints set by some other experimental groups like xenon100, lux and supercdms(ge ). here  , we discuss the possibility of ameliorating the tension among different experiments by considering the uncertainties in nuclear physics describing how the struck nucleon is distributed inside the nucleus as well as the use of different distributions for protons and neutrons instead of the commonly used empirical charge distributions for a target nucleus in dark matter direct detection experiments.
the elastic properties of ultrananocrystalline diamond films ( uncd ) and diamond nanocomposites ( @xmath4d/@xmath5-c ) are investigated using monte carlo simulations.   the bulk and young s moduli of these materials are evaluated at the equilibrium state, and the effects of the grain size on the elastic response are investigated. in both cases, the results show that the elastic moduli are higher than those of the tetrahedral carbon matrix used as the embedding medium.. the experimental results are compared with the results obtained using the environment - dependent tight - binding model of tang, wang, chan, and ho @xcite, which provides superior accuracy in the energetics compared to the empirical schemes.
we present a database of pulsational results that can be useful to perform asteroseismological studies of zz ceti stars.   these include the internal chemical profiles and the run of the brunt - visl and lamb frequencies, as well as a large set of adiabatic pulsation periods, time - averaged oscillation kinetic energies, and first order rotational splitting coefficients. for each of these parameters,   we have computed the evolutionary history of the progenitor stars using fully evolutionary ( that is, non static ) da white dwarf models. here  , we describe the input physics of our models and the pulsation computations, and then we present the format of our database.
we study a sample of gamma - ray bursts ( grbs ) with x - ray flares that have been observed by the swift x - rays telescope ( xrt ) for a sufficiently long time and for which redshift information is available.   we compute the average energy output from the inner engine as a function of the time elapsed since the grb explosion, and we compare it to several mechanisms for energy extraction from a magnetar or a black hole. in the case of the late time outflow,   the progenitor star plays a key role in shaping the flare light curve.. the results show that the main mechanism for the late timescale of the flares is the same as that for the prompt phase, but that the rate of the flare decay is much faster than that of the prompt phases.    the origin of the rapid rise and decay of the high - energy outflow is not related to the outer engine, but to the formation of a new generation of flares at the site of the initial explosion.
microlensing of the milky way by gravitational microlensing ( gm ) is a powerful tool for studying the dark halo of the universe.   it has been shown that objects with masses under about @xmath19 can not comprise the entire galactic halo at the 90% c.l., but we have used a different technique to set limits on the prevalence of low mass machos ( massive compact halo objects ). using the first two years of lmc data from the eros collaboration @xcite, we find that the presence of very few spikes in the lightcurves of stars with durations under a few days is sufficient to strongly constrain the existence of low - mass objects in the halo.
super - luminous supernovae ( slsne ) may be powered by a collision between the sn ejecta and a massive shell or wind of circumstellar material ( csm ). in this work  , we study the possibility of the non - thermal emission from the shock interaction of a sn embedded in a dense csm. in particular, we focus on the secondary electrons and positrons expected from the same @xmath0 collisions that give rise to neutrinos and gamma rays.   importantly, we show that these secondaries can emit detectable synchrotron radiation at high - frequency radio wavelengths including mm / submm and fir bands.
the case for supermassive black holes ( bhs ) in galactic nuclei is now very strong, and in a few galaxies almost irrefutable.   although the masses of the detected bhs comprise on average only @xmath6 of the mass of their host spheroids, there is a growing body of work suggesting that the dynamical influence of a supermassive bh can extend far beyond the nucleus. here   we derive a simple analytical model for the decay of supermassive binary bh binaries which reproduces the results of the@xmath0-body simulations, then use it to estimate the coalescence time of the bh binary. using this model, we show that the coalescent rate of the binary is about 1.5 times faster than the rate of galaxy merger, and that the process of coalescence is driven by the capture and ejection of stars from the binary via three - body interactions at a rate that is nearly independent of the rates of the first two processes. when the binary separation has fallen to the value at which gravitational radiation becomes efficient, the bhs coalesce.
we compare the results obtained using genie  @xcite and gibuu @xcite event generators for the measurement of @xmath0 disappearance in the gev region.   we evaluate the impact of several aspects of nuclear models and their differing implementation with respect to the ability to measure the so - called atmospheric parameters, @x math2 and @x Math3, in an experimental setup which is similar to t2k. by changing the target nucleus from carbon to oxygen  , we find that the effect of fitting data obtained with one generator and the other results in dramatic shifts due to different modeling and implementation of final state interactions and nuclear models. also, the absence of multi - nucleon correlations in the fit can induce a bias between 1@xmath4 and 3@x maths4 on the results for both of the oscillation parameters.
strong quantizing magnetic field of neutron stars can change the tensorial character of transport coefficients of dense neutron star matter in presence of strong magnetic field @xcite.   the present paper presents a relativistic version of pauli paramagnetism of neutron Star matter in @xmath1-equilibrium and extends the work of shulman@xcite to the high density region ( i.e., in the rate - limiting regime of neutron star subject matter ). using the fully polarized configuration of electronic components,   it is shown that the fully polarization configuration of electrons / protons puts the system in a state of equilibrium with the magnetic field strength at the core of the neutron star @x Math2 g @xcites.    the results of this study are discussed in detail.
high - temperature tomographic x - ray imaging of a mixture of quartz sand, sodium carbonate and calcium carbonate has been performed on the id15a beamline at the european synchotron radiation facility ( esrf ).   the sample was heated from room temperature to @xmath12c, and 3-dimensional ( 3-d ) scans of the sample have been acquired every @x Math12c. in order to obtain quantitative information,   all of the 175 grains in the analyzed volume at room temperature have been identified. as temperature increases, the grain size of the initial pile shrinks, with the appearance of a jagged and fuzzy reaction layer. between room temperature and@xmath13c, many sodium carbonic acid grains have unexpectedly broken up, forming a new high porosity material that sticks to either of the adjacent sand grains or sticks to unreacted parts of the sand grains. this newly formed material is rapidly covered in a loose shell of a loose silica shell of the original sand grains, which is responsible for the formation of crystalline sodium silicates. during the first few minutes of melting, the solid - solid contacts between the grains break up and form a liquid
the vertex position detector ( vpd ) at the relativistic heavy - ion collider ( rhic ) @xcite has been upgraded to increase the readout detector channel count on each side of the solenoidal tracker at rhic ( star ).   the vpd provides the primary detector input to the star minimum bias trigger in a@xmath1a collisions, and can measure the location of the primary collision vertex along the beam pipe, @xmath6, up to nineteen times in each event. for lighter beams such as p@x Math1p and also au@x math1au beams at lower beam energies, the efficiency of the pvpd for providing the vertex location and the event time degraded due to the relatively lower multiplicities of very forward prompt particles in such collisions. to address this, the pVpd was upgraded to include a larger number of readout channels on each sides of star in the same angular acceptance. with the new vpd, the start - timing and @x maths6 performance of the system   were improved.
the parametric scattring of two pump polaritons from the pump into the signal and idler states of a cavity exciton - polariton quasiparticle, known as the parametric oscillator, is studied experimentally under pulsed pumping and pulsed excitation.   previous theoretical treatment was based on the heisenberg equations @xcite. in this paper   we develop a general quantum formalism allowing an analytical treatment of the parametry oscillator both below and above the stimulation threshold, provided the total number of polaritins is large. using the hyperspin pseudovector whose components describe the pair correlations between pump, signal and IDler states, we obtain classically stable trajectories for the hypespin dynamics. within an approach close to that used earlier by one of us to describe the dynamics of large total spins of magnetic polarons, we analyze the schroedinger equation in the hypers pin space, and show that the number of relevant variables in the equation can be reduced, and its quasi - classical solution can be found.    it turns out that the parameters of the polynomials are non - correlated and that the squared wavefunction of the parameteretric oscillation
dark energy is a component of the universe with negative pressure, and its existence is strongly supported by observations of supernovae of type ia ( sne ia ) and the cosmic microwave background ( cmb ).   the dark energy equation of state, the ratio @xmath8 of its pressure and energy density, is an important parameter for the study of dark energy. in order to determine whether or not the darkenergy is a cosmological constant, it is crucial that the equation of states and its red shift derivative be determined observationally. here  , we analyze the latest data from wmap, sn ia searches, and the sloan digital sky survey. using a minimization procedure, we find that the dark energies of the sn ian and sloan ian regions are significantly different from those of the wmap project.    we also find that strong priors can lead to underestimates of the uncertainty in @x Math0 by a very large factor.. we discuss how standard likelihood marginalization can give a misleading impression of the uncertainties in @Xmath0.
tod @xcite introduced the notion of quasi - local charges in non - abelian yang   mills theories, following the analogous twistorial definition of quasi-local energy - momentum and angular momentum of penrose in general relativity.   his construction is based on the use of the holomorphic _ and anti - holomorphic cross sections of a hermitian vector bundle. to be able to see the closest analogy between general relativity and proper non -Abelian gauge theories as possible, it would have to be considered the latter with the lorentz ( or its covering group, the @xmath0 ) gauge group. here   we show that the concept of charge can be formulated and studied in terms of electric and magnetic charges, and that the resulting expression in the standard small sphere and large sphere limits is similar to that of the newman   penrose quantities. for globally trivializable bundles the modified construction also gives vanishing magnetic charges.
abstractthe bounce characteristics of baseballs have a large influence in baseball games ; thus, baseball organizations often establish rules concerning official balls.   the nippon professional baseball organization ( npb ) first introduced their official baseball in 2011, which was used in both pacific and central league baseball games. to obtain the distribution function approximating these data, we fitted the mixture distribution of the normal distributions of the distribution parameters @xmath8, @x Math9,@xmath10, @ xmath11, @Xmath12, @xcite, and @x math13 with the mixing parameter @x maths13. the results show that the probability of choosing the height of the center of mass of a baseball is almost constant, except at @xMath14, which is the highest position. on the other hand, the frequency of the ball hitting the strike zone is relatively small, which may be attributed to the fact that the balls are difficult to strike when they are inside the strike zones. according to the official baseball rules in japan and the average height of japanese professional baseballs, the balls should be made by tightly winding yarn around a small core and covering it with two strips of white horse
a topological crystalline insulator ( tcis ) is a new class of topological insulating ( ti ) phase featuring massless dirac - like boundary states whose robustness is guaranteed by the time - reversal symmetry ( trs)@xcite. here   we examine strain effects on the ( 001 ) surface of the pb@xmath0sn@x math1(te, se ) tcis using an effective four - band model and show that certain mirror - symmetry - breaking strains induce hedgehog spin texture with out - of - the - plane spin - polarization at the dirac point.   our results thus identify a possible new pathway for realizing tci - based spintronics devices without requiring a trs breaking field.
decoherence is a nearly universal effect in quantum systems, and one which plays a central role in the quantum to classical transition.   however, the word " decoherence " is often used to denote several related, but distinct concepts. here   we will consider a specific example of a quantum system, coherent electrons coupled to the quantized electromagnetic field, such as that illustrated in the electron interference experiment, where the coupling allows for photon emission by the electrons, leading to decay of the aharonov - bohm phase relations between the quantum state of the electrons and that of the electromagnetic field. at the same time, we will discuss the effects of photon emission on the coherence functional, which can be expressed either in terms of dephasing or of the revelation of " which path " information.
self - assembled semiconductor quantum dots ( qds ) have attracted a large interest because the discrete and isolated energy levels due to the 3d confinement can be utilized in high - efficiency and low - threshold current lasers,@xcite single photon emitters and in quantum computing applications ( qubits ).   recently there have been reports on 1.55 @xmath3 m inas / inp qds lasers with a high - gain and a low- threshold current which opens up the possibility to integrate quantum dot material into an optical cavity @xcite and hence to reliably fabricate a single photon source in the telecommunications wavelength range. in this paper, we perform a comparative study on the inas or inp self - assembled qds using an atomistic pseudopotential method.    we find that there are significant differences in the electronic structure between the two systems, including the single - particle energy levels and optical properties. these differences, which have not yet been paid enough attention to, could be revealed in the future high - resolution optical spectroscopy @xcites and charging experiments.
the geodesic principle is a theorem of general relativity, which states that in the absence of external forces, bodies will move along timelike geodesics.   recently, i have shown that this theorem can also be understood as a theorem for geometrized newtonian gravitation. when one attends carefully to the details of these theorems,   several complications arise concerning the strength and status of the geode - principle - as - theorem.
we study the asymptotic behaviour of self - similar graphs by analysing the singularity of the green function of the simple random walk on the sierpiski graph.   this function describes the returning of the random walk to a certain origin vertex. in @xcite we introduced a combinatorial substitution based on path arguments which allows us to obtain a functional equation for this green function and iteratively iterate this equation to obtain the analytic continuation of the Green function as a rapidly converging product of rational terms. in the present paper   we apply this analysis to the case of symmetrically self - like graphs with an origin vertex, which are also known as self - similarity graphs with two or more boundary points. using this analysis we show that the natural oscillation of the red curve of the siersi graph is due to the convergence of the transition function to the fatou set at the origin vertex of the cell graph.
quasar clustering is strongly correlated with luminosity at redshifts approaching @xmath7.   we have discovered a pair of binary quasars that are separated by 21  deg from each other on the plane of the sky and by a small velocity window in redshift space ( ~21  mpc proper ), which is the highest redshift binary quasar pair discovered to date. using the cfhtls - wide survey @xcite, we show that this pair is a binary quaser, rather than a gravitational lens, and that its separation is highly luminosity - dependent. during a survey of @x Math21 quasar candidates, we find that the pair is located in the sdss stripe 82 region, where it is separated by about 21  kpc. here  , we discuss the discovery of this pair, our reasoning for why it is a twin quasar, and the implications of such a pair for quasar clusters at@xmath22.
we investigate a geometrically thin, axisymmetric keplerian finite accretion disk with a viscosity in the form @xmath6, which is time - independent.   we obtain green s functions (  ) to compute the viscous angular momentum flux of  @xcite. ] and the accretion rate@xmath8. for arbitrary initial surface density distributions,   different boundary conditions are considered : no stress or no accretion at the inner boundary, located at the zero radial coorinate, zero or time - dependent mass inflow at the outer boundary. using the method of green s function analysis, we find a solution to the problem of the viscously evolution of an accreting disk with the constant outer radius.
a key question in star formation research concerns the mechanisms behind the launch of jets from young stars.   it is generally acknowledged that magneto - centrifugal forces are responsible for jet launching, but observational backing for canonical models would require proof of rotation around the symmetry axis, close to the base where the jet is launched. here   we report findings for another three sources ( of eight in the survey sample ) for which the data have already been acquired, i.e. the bi - polar jets from the t tauri stars th28 and rw aur, and the blue - shifted jet from lkh@xmath0321. using high angular resolution spectra taken with the hubble space telescope imaging spectrograph ( hst / stis ), we show that the origin of the jet can be optically traced back to its origin at a distance of 51, 195 and 233 au from the source for th28, rw Aur, and lkh @xmath3.2, respectively, and at 0@x Math3.3 for the blue- and red - shifted lobes of the rwaur jet.    the location on the disk plane of the launching point of the wind (
the coefficients of thermal expansion ( cte ) of materials are important for understanding the potential for temperature gradients or other thermal stresses to cause electronic devices to fail.   while the cte for many materials have been cataloged, the set of known negative thermal expansion materials is small, and materials appropriate for specific applications may not yet be available. a means of rapidly predicting the thermal expansion properties of yet - to - be investigated materials will be extremely useful. in this work  , we propose that an approach to predicting thermal expansion can be found by scanning the literature for the structures of crystals, focusing on quantities that may have a relationship to the entropy of the material and its potential to increase or decrease with respect to pressure, such as the space occupied by ions, theircoordinations, and the distribution of atomic masses. using the inorganic crystal structure database ( icsd ) @xcite and the crystallographic open database ( cod ), we show that the theoretical model for thermal expansion in a single structure, with expanding bonds modeled with first- and second - neighbor interactions via morse potentials, can be varied from negative to positive thermal expansion by increasing the second - neighbors interaction strength relative to the first - neighbors.
the abstract state machine ( asm ) thesis, first proposed in @xcite, asserts that every algorithm is equivalent, on its natural level of abstraction, to anstract state machine.   the present paper extends this thesis by removing the restriction to " ordinary " algorithms. here   we provide postulates and definitions describing a general notion of interactive, small - step algorithm. in a companion paper  , we also extend the syntax and semantics of abstract state machines ( asms ) so that non - ordinary algorithms become expressible. there we provide syntax for asms incorporating interaction that need not be ordinary, verification that asms satisfy the postulates, and proof that all algorithms satisfying these postulates are equivalent, in a strong sense, to asms.
we have used the grid method to investigate the intermittent progress of the microstructural strain field in a cu   - al - be single crystal across the mechanically - induced martensitic transformation in shape - memory alloys ( smas ).   this was done through uniaxial force - controlled loading tests, during which we have recorded and analyzed the super - elastic and hysteretic stress - strain behavior of the sample, as well as surface strain data in the forward and reverse transition. using an experimental apparatus based on gravity, we have applied a low - rate perfectly monotonic force, controlled by very slow flow water pumps, to the sample at almost isothermal conditions, enabling us to highlight the intermittency in the phase change in the alloy, through the quantitative analysis of the strain field features measured over the sample. for the forward transition,   the results show that the strain changes from a peak in the vertical direction to a trough in the horizontal direction, with the latter exhibiting a much more rapid onset than the former, while the reverse transition exhibits a slower onset, with both phases progressing through a set of discrete avalanche - like events, corresponding to transitions between neighboring metastable states.
viper is a web - based tool for the archivist of astronomy repositories.   it allows the user to create a class with restrictions on its properties and to apply a variety of operations to these properties to retrieve data from astronomy repositories, and then to convert these data into the " goal" form. in this work  , we have focused on application of some semantic technologies such as owl ontology to understand the relationships between astronomical objects and their properties. using this knowledge, our tool may aid the user in the selection of appropriate properties and applicable operations when designing their science workflow.
a new purification mechanism for the purification / distillation of quantum states @xcite is proposed.   it is shown that repeated measurements on a system, say a, result in a purification of another system,say b, in interaction with a, if certain conditions are satisfied. under certain conditions,   a particular entangled state between the lowest two modes of each cavity is extracted, irrespectively of the initial cavity states, by repeatedly performing measurements on x which interacts with both a and b. the results obtained and the implications of these results are discussed.
the thick disk is a ubiquitous feature among spiral galaxies, and its formation must be a common stage in the early evolution of late - type galaxies.   we are undertaking an extensive survey aimed to reveal the kinematical and chemical vertical structure of the galactic thick disk @xmath61200 red giants defined by @xcite, vertically distributed with respect to the galactic plane in a cone of fifteen degrees radius centered on the south galactic pole. for the first time, we show that the observed decrease of rotation velocity with distance from the plane points to a low - latitude merging, while the observations are also gathering information about the spatial variations of the chemical composition and velocity distribution.
the influence of elastic effects on the kinetics of solidification or melting processes is well - known, but the influence on the thermodynamics of the transitions between different phases has been thoroughly discussed in the literature @xcite.   we follow here the same successful concepts to formulate a free boundary description for the transformation kinetics in solids, now including the important effect of elasticity. as for the dendritic growth, we focus here on the regime of diffusion limited growth, where propagation of a front generates or consumes latent heat, which has to diffuse through the system, and we assume that this is the rate - limiting process. at the interface between the solid and melt phase the temperature or concentration is close to its phase equilibrium value, and the release of latent heat due to partitioning leads to a jump in the corresponding fluxes at the interfaces, which are then directly related to the local interface velocity. finally, we provide a detailed description of the microstructure evolution on the level of individual grains in a polycrystalline structure.
white dwarfs are the end products of stellar evolution for 98% of all stars, and are the first structures to form in the galaxy.   their distribution and detailed properties represent a unique link to explore the nature of the now - evolved population ii progenitors of globular star clusters, where all of the remnants are co - spatial, have the same total age, and evolved from stars with the same metallicity, yet over a range in initial mass. here  , we review the current state of knowledge about the mass of white dwarfs forming in globular clusters, and discuss the implications of these findings for our understanding of the formation and evolution processes of galaxies.
the reentrant cavity transducer is a highly sensitive microwave mode, which can be used for displacement measurements, sideband cooling, amplification of mechanical motion, and for investigating quantum behavior of macroscopic mechanical resonators@xcite. in this work   we show for the first time that higher order modes exist in the cavity, which is of general interest as many of these applications would benefit directly by having more than one highly sensitive transducing mode in the cavities.   the new mode is based on the @xmath6 mode of a cylindrical cavity and consists of a central post and an additional ring positioned at the two anti - nodes of the azimuthal magnetic field of the cavity. to create the higher order mode we conceive the concept of theReentrant - ring ( rr ) cavity, while the common reentrants are single - post ( sp ) cavities, which consist of an empty cavity and a central posts.. the cavity was simulated using the finite - element method ( fem ) and in comparison with the sp cavity ( of the same size ) the rr cavity is shown to have a higher displacement sensitivity. several cavity configurations were examined experimentally,
the li - xia transmission scheme is extended to a more general transmission scheme that can achieve full asynchronous cooperative diversity for any number of relays.   the conditions on the distributed space time block code ( dstbc ) structure that admit its application in the proposed transmission scheme are identified and four group decodable distributed differential stbcs applicable in this scenario are proposed. moreover, it is shown how differential encoding at the source node can be combined with the proposed transmitters to arrive at a transmission scheme which can achieve complete cooperative diversity without channel knowledge and in the absence of knowledge of the timing errors of the relay nodes.
we consider how the axial anomaly of quantum chromodynamics can be isolated through a triple - product momentum correlation in neutron radiative @xmath0-decay.   the correlation is both parity- and naively time - reversal - odd, so that it vanishes in the standard model save for effects induced by final - state interactions ( fsi ). nevertheless, the correlation can be generated by sources of pseudo - chern - simons ( pcs ) violation beyond thestandard model, and such couplings, being spin - independent, are not constrained by the nonobservation of the neutron electric dipole moment.. we consider the limits on its strength which can be determined at existing and anticipated facilities, as well as the size of induced correlations from known fsi.
the opacity of the universe to @xmath0-rays at redshifts from 4 gev to 100 tev is calculated for two evolution models, the " baseline" ( b ) model and the " fast evolution" ( fe ) model.   the results are compared with the recent data from the _ spitzer _ infrared observatory the _ hubble _ deep survey and the galaxy evolution explorer.    the results show that the fe model is more consistent with the observed star formation rate than the b model.
quantum state estimation is a fundamental task in quantum optics.   it is also an indispensable component of several algorithms in quantum information processing, e.g., the measurement of the quadrature amplitude and phase of a weak ac signal in the microwave range. here  , we present a new method for simultaneous adaptive estimation of both phase and amplitude of the phase arg(@xmath1 ) of coherent quantum states of light at fixed coherent state amplitude using quantum state tomography ( qsot ). to achieve this,   the input state to the interferometer is not separable from the photon number eigenstates in the output arms of theinterferometer, and its creation is currently an open question. as a first step toward this goal, we have developed a novel approach to the optimization of adaptive phase estimation by combining the properties of the quantum state and the phase space representation of the wave function. with the help of quantum mechanics, we show that the proposed method is able to beat the standard quantum limit for the precision of phase estimation, which is due to the complementarity between photon number and phase variance scaling.
the contribution of low- and intermediate - mass stars to the chemical enrichment of the interstellar medium ( ism ) during the rgb and agb phases, both characterized by the occurrence of mass loss and events of surface chemical pollution ( dredge - up episodes ), is analysed in detail by means of synthetic agb models.   the results of these models are compared with those of the observations of high red - shift systems, which have recently been used to trace the history of chemical evolution and of star formation in the universe. a set of stellar yields from @xmath1he,@xmath2c, and @x Math3n, as well as from the most recent observations of @x math4o, is presented for each of these stars, and the contributions of the latter to the n / o ratio and the carbon star luminosity functions are also discussed.
we study the dynamics of @xmath0-dimensional charged black holes using the semi - classical effects of hawking radiation.   we solved time - dependent einstein and field equations using the double - null formalism using the reissner - nordstrm solution, and we report results for cases of three - dimensional charged black hole solutions in an anti de sitter background with the hawking temperature of 0.5 k. we also discuss the mass inflation issue in three - dimensionally charged blackholes.
high - velocity clouds ( hvcs ) are high - velocity gas that have anomalous velocities that are incompatible with what is expected from a simple galactic rotation model.   the origin of these clouds has been a source of speculation since their discovery by @xcite in the early 90 s, but the lack of distance measurements has hindered the progress in understanding the role that hVcs play in the formation and evolution of our galaxy.    we describe a set of geometrodynamical methods for determining distances to streams of hi gas comprising the hvc complexes. using data from high resolution spectroscopy  , we show that it is possible to determine distances from radial velocity alone for many of the hvc complexes, including the magellanic and sagittarius streams ; however, this is not the case for the most distant streams such as the Magellanic stream which are thought to be composed of newly accreted neutral hydrogen gas left over from the formation epoch of the galaxy. instead, we use heliocentric radial Velocities corrected to the galactic standard of rest ( gsr ) as a lowest order approximation to the galactocentric radius of the universe.
we have developed a statistical mechanical technique for studying the equilibrium structure and kinetics across phase transitions in heteropolymers @xcite using the gaussian self  consistent ( gsc ) method.   we have performed averaging of the gsc equations over the quenched disorder in the monomer amphiphilic strength, yielding a closed set of kinetic equations for description of random copolymers with a gaussian distribution of the disorder. to demonstrate the strength of the extended gsc method we consider a number of interesting examples of heteropolymer sequences where different kinds of interactions, such as the hydrodynamic interaction, may be straightforwardly incorporated into the scheme. from these   a rich and nontrivial physical picture emerges as a result of this theoretical progress.
bose - einstein correlations ( bec ) between identical bosons are since long time recognized as very important tools in searching for dynamics of multiparticle production processes because of their ability to provide the space - time information about them.   this is particularly important for heavy ion collisions which are expected to provide us with the new state of matter, the quark gluon plasma ( qgp ) @xcite. here   we present a new model of hadronization in which bose-einstein statistics is not only included from the very beginning on a single event level, but it is also properly used in getting the final secondaries. using monte carlo event generators,   the same process is simulated by changing the outputs of the respective event generators in such a way as to reproduce the characteristic signals of bec obtained experimentally. under these conditions   one gets the correct bec pattern ( i.e., correlations ) and fluctuations ( as characterized by the observed intermittency pattern ) at the same time.
the theoretical description of slow dynamics is a crucial point to elucidate the nature of the glass transition in structural glass - forming liquids.   one of the commonly used approaches, mode - coupling theory ( mct ), was from the very beginning designed for the supercooled simple liquids @xcite, i.e. for the non - disordered models and has been substantially extended to the case when the time translation invariance and the fluctuation - dissipation theorem do not hold any more. here   we show that the full equation of motion for the time dependent density - density correlator for a model with a long range interaction is obtained by using the expansion around the saddle point solution of the mean - field solution and show that a " glassy " solution does not exist.
type ia supernovae are thought to result from accreting c - o white dwarfs in close binaries.   the main observable characteristics of single type ia ( sn ia ) supernova light curves and spectra are related to the nucleosynthesis, which is crucial to study the unresolved issues regarding the explosion models and the progenitors of sne ia. here   we show that the synthesized amounts of some neutron - rich species differ between the chandra and sub - chandra models because of the difference in the central densities of the exploding white dwarf. using a combination of experimental and theoretical calculations, we find that the deflagration to detonation transition ( ddt ) may be triggered by the burning of the central region of the white dwarf, leading to the production of fe - peak elements and intermediate mass elements such as ca, s, si, mg, o, and mg2 +, but not by the formation of stable ni - peak element @xmath6ni. on the basis of these results, we propose that the ddt could be induced by thermonuclear burning in the outermost regions of the collapsing white dwarf or by a violent merger of the two white dwar
massive clusters of galaxies are rare objects, and the number of relaxed high redshift massive clusters at z@xmath00.6 is even smaller.   we have used x - ray spectroscopy to study the properties of a relaxed cluster of massive galaxies at z=0.6, clj1226.9 + 3332, which form a complete sample of 16 clusters known at this redshift. using two - dimensional analysis of the @xmath15 and @x Math2 data, we find that the cluster is isothermal out to 45% of the virial radius, and has a mass of ( 1.4x10x10@x math6 ) within its core radii. in contrast to the other high temperature cluster known at z<0.8, the cluster appears relaxed, with a temperature of 11.5 kev, a bolometric luminosity of 5.4 erg s/s, and a gas mass of > 200 times the critical density at the redshift of each cluster. for the cluster at z>0.7,   the total mass is estimated to be ~50.2 times higher than that of the other cluster, and there is a metal abundance
we conduct a finite population analysis of evolutionary dynamics of a general two - person game with zealots.   we assume a well - mixed population of ordinary players and zealous cooperators in the presence of zealots, and we examine the mean fixation time of the strategy selected by the zealots as a function of the payoff matrix, population size, number of zealous players, strength of selection, and the number of non - zealous cooperative players in the population. for the case of a prisoner s dilemma,   the fixation time is found to be 1.5    0.2  min.    the fixation probability of the chosen strategy is calculated by considering the evolution of the population under evolutionary dynamics defined as follows : each player plays a symmetric two -person game with all the other players in a unit time. using the moran process, we select an ordinary player with the equal probability of selecting the strategy of the previously selected player and replace it with that of the player whose strategy is to be replaced by the one chosen by the Zealots. then, we estimate the mean fixation time of this strategy from the variance of the average fixation probability obtained in the previous study. 	 the
the abundance of @xmath0 in interstellar space is determined by the detection of an intense line at a wavelength of 3.4  mm.   this line is the first to be detected in the near 4  and first overtone near 2  bands of the fundamental vibration - rotation band, which are for the first time used to measure the abundance of simple molecules in dark clouds.
the chiral vortaic effect ( cve ) is a new coupling of the topological qcd field and the electromagnetic field in @xcite, which leads to the appearance of the same electromagnetic current as the renowned chiral magnetic effect. here   we suggest a straightforward generalization of cve resulting in generation of all conserved - charge currents.   in particular, we address the case of the _ baryonic _ charge and the corresponding asymmetries of baryons, especially neutrons ( not affected by cme ), which can be measured by the multipurpose detector@xcite at the nuclotron - based ion collider facility ( nica ) at the joint institute for nuclear research ( jinr ).
the cast experiment ( cern axion solar telescope ) is designed to detect solar axions or to improve the existing limits on their coupling to photons.   the operation of cast has been divided in two phases in order to scan the axion phase space : during phase i the magnet pipes were kept in vaccum while in phase ii they will be filled with buffer gas ( he ) to look for heavier axions. following the particular demands of the cast experiment, the micromegas models used were filled with argon / isobutane mixture ( 95%-5% ) in atmospheric pressure and were supplied with an aluminized polypropylene window supported by a strong - back. also the frame of the detector was made of low natural radioactivity materials ( plexiglas and plastic ) to reduce the background.the 2003 data have been evaluated and the first results have been published@xcite, while the 2004 data analysis is still in progress.
the large hadron collider forward ( lhcf ) experiment has revealed the inclusive production rate of neutral pions at very forward rapidities larger than @xmath4 and very low transverse momentum@xmath3 ( @x Math5 gev ) in collisions with protons and nuclei at @x math6 tev.   the results are compared with the predictions of several hadronic interaction models based on distinct assumptions.. in particular, with models which assume that the particle production at veryforward rapidities is dominated by nonperturbative ( soft ) physics, which is justified, _ in a first approximation _, considering the range of transverse momenta probed by the experiment.,1 in this letter we propose a distinct perspective for the description of the lh cf data, taking into account the new dynamical momentum scale, the saturation scale, which controls the main characteristic of the process and whose evolution is described by an infinite hierarchy of coupled equations for the correlators of wilson lines @xcite. using this new momentum scale  , we show that the model can be used to calculate the neutral pion production at high-@xMath3 using a perturbative
the large scale homogeneity and isotropy of spacetime are two fundamental tenets underpinning modern cosmology.   the aim of this work is to quantify the extent to which current large scale structure ( lss ) data sets are consistent with the underlying assumptions of isotropy and homogeneity. in this work,   we analyse the local galaxy distribution using the 2mass extended source catalogue @xcite, using the photometric redshift data developed recently in @xmathite. using a full sky galaxy survey   allows us to examine the angular distribution of galaxies on the sky, and the volume probed in the full 2mass catalogue allow us to make magnitude cuts to test the redshift distribution. in order to do so, we use a combination of parametric and non - parametric methods to reconstruct the luminosity function, the number of galaxies per unit luminosity per unit volume for a given volume. by averaging over sufficiently large volumes  , we show that the observed local galaxy density is systematically lower than expected, out to co - moving distances. from this we construct a three dimensional model of the local universe, which is then used to investigate the existence of preferred directions in the data, which are indicative of a breakdown
the statefinder pair @xmath0 is a geometrical diagnostic of dark energy, in the sense that it is constructed from a space - time metric directly, and it is more universal than " physical " variables, which depend upon properties of physical fields describing dark energy.   the statefinder probes the expansion dynamics of the universe through high derivatives of the scale factor@xmath12 and @x Math13 and is a natural next step beyond the hubble parameter @x maths14 depending on @x math15 and the deceleration parameter @ xmath7 depending on ~12. here  , we discuss the evolution behaviors of the cosmological evolution behavior of two new diagnostics of dark energies, namely, the degeneracy of @xMath18 and the acceleration probe @x mathematics8, which are derived from the cosmology of the friedmann - robertson - walker ( frw ) universe and the so - called statefinder model, respectively. for each of these two diagnostics, we have taken into account the existence of a negative pressure component  dark energy  with large enough negative pressure to explain the cosmic acceleration observed in type ia supernovae ( snia ).
we theoretically study the spin and charge generation due to the electric field of the twisted light beam on a disordered surface of a doped topological insulator ( ti ) by using the green s function technique.   we analyze the linear response function of the spin density to a space - time dependent external electric field in the presence of a three - dimensional topological electric structure@xcite, where the spin direction and the orbital angular momentum are perfectly locked to be perpendicular to each other, which is dubbed spin - momentum locking. because of this lock,   the charge current generated along the direction of the environmental electric field causes the spins to emerge in the perpendicular direction.. the results show that the spin polarization of the light is not transfered to the spin angular momentum since the beam waist is much larger than the width of the electron wave function, and hence each electrons feels locally uniform electric field.
the problem of finding an optimal feedback protocol for a single qubit is very difficult to solve numerically.   we address this problem by focusing on the regime of good control, and analyzing the dynamics under measurement in the steady - state. using markovian noise processes that are symmetric about the @xmath1-axis of the qubit, we find that the optimal protocol is the one that moves the state closest to the desired state at each timestep.
the time scale for dust settling in protoplanetary disks is one of the most fundamental processes in planetesimal formation.   it is crucial to understand how to overcome the meter - size barrier, i.e., the infall of dust caused by headwinds, to form planetesimals out of newly condensed dust particles, because the failure to do so would leave little chance for subsequent planetary formation. using a simple thermodynamically - consistent model, we show that the existence of dust affects the opacity of the atmosphere by orders of magnitude, thus affecting the temperature structure of the disk and changing the chemical composition of the coexisting gas. as the dust grains settle through a vertical temperature gradient, the stable phases of dust - composing elements are likely to change, possibly altering the stability of the stable phase, and modifying the opacity. this feedback between physics and chemistry during the dust settling process   is quantitatively demonstrated by calculating the time scale of vertical dust settling from the rosseland mean opacity and the stefan - boltzmann constant of the vertical radiation flux. our model shows that the effect of chemistry on dust settling is more complex than previously thought, with the presence of dust having a major impact
we present time resolved optical spectroscopy and photometry of the helium rich star sbss1108 + 574 ( sdssj111126.83 + 571238.6 ), a new su uma dwarf nova.   it was discovered in outburst on 2012 april 22 by the catalina real - time transient survey ( crts ; @xcite ), and reported as a new superoutburst by@xcite earlier this year. during the outburst,   the system brightened by several magnitudes for a period of days to weeks, which was thought to be caused by thermal instabilities in the accretion disc. here   we show that the observed outbursts were caused by periodic modulations in the lightcurve, known as superhumps, which are caused by tidal interactions between the disc and the donor star.    the superhump period is typically a few percent longer than the orbital period, and is related to the mass ratio of the system.
a very common statistical procedure is obtaining a confidence interval for a physics parameter of interest, when there are uncertainties in quantities such as the acceptance of the detector and/or the analysis procedure, the beam intensity, and the estimated background.   we aim to study and compare different approaches for determining confidence intervals for this problem. using a bayesian approach  , we find that the most appropriate method is the one which takes into account the coverage of the ensemble of experiments measuring the parameter @xmath0 counts, and assumes that the acceptor and the background are poisson distributed with mean @x math4.. we also find that it is possible to obtain confidence intervals which are larger than unity for some values of the parameter, but not for all values.
peptide nucleic acids ( pnas ) are synthetic oligonucleotides with a backbone that recapitulates dna s inter - nucleobase distances.   pnas were developed as dna mimics in order to recognize dna double helix and to form hybrid duplexes with dna or homoduplexes@xcite. unlike dna which has a helical conformation due to its chiral centers, standard pnas, with no chiral carbon, have no defined structural conformation in solution. here  , we explore the biophysical properties of pnas built with a chiral center. using circular dichroism ( cd ) and liquid state nuclear magnetic resonance ( nmr ), we show that pna homod uplexes are formed by base - pairing with @xmath0-modified pnas. working in neutral conditions,   nmr experiments bring information about the imino hydrogens engaged in the watson - crick, hoogsteen, reverse hoogstein, or wobble bounds. melting transitions ( @x math1 ) of the highlighted pnahomodupplexes were determined by cd and absorbance experiments.. circular dich
vesicle dynamics has long been investigated both experimentally and theoretically.   the knowledge of the microscopic relaxation can also be used to predict the macroscopic rheological property of the vesicle solution @xcite. in this paper, we consider the two - bilayer vesicles which are the simplest multi - lamellar vesicular ( mlv ) systems. using a concrete calculation, we calculate the dynamic relaxation rates, as well as the rheology response of the two-layer - vesicels. from the experimental point of view, it is hard to prepare vesons with exactly two bilayers. however, such a concrete calculations provides a clear picture of how the interaction between the two membranes affects the relaxation rates for the squeezing flow which arises exclusively in mlv.. since our method can be extend to vesarticles with more than two bil layers, a more specific calculation can be performed similarly.    based on the analysis below, we find that the squeezing mode makes the dominant contribution to the complex viscosity for strongly interacting bilayers ; however, when the gap between the 2 bilayers is smaller than a characteristic crossover gap, the fast undulation mode becomes the dominant mode
the standard model ( sm )  @xcite predicts the existence of quartic gauge couplings ( qgcs ) leading to @xmath4 production via @x Math11-channel exchange of a@xmath12 or z boson.   we have measured the cross section measurement for the process @x math0 and the determination of an anomalous qgc using the data collected in 1998 with the l3 detector at @x maths17 corresponding to a total integrated luminosity of 176.8pb@xMath2. from the results obtained, we propose that the presence of anomalous coupling couplings would enhance the rate of x - pair production, especially for the hard tail of the photon energy distribution and for photons produced at large angles with respect to the beam direction.
the existence of a supersolid state, where the solid and superfluid states coexist, has been discussed in the hard - core bose - hubbard model on a layered triangular lattice.   we systematically study ultracold bosons in an optical lattice with the layered triangular structure using cluster mean - field theory and the density matrix renormalization group ( dmrg ) method. to clarify this point, we study ground - state properties of interacting bosons on the layered system and discuss how the interlayer couplings affect the stability of the supramolecular supersolid states.    we demonstrate that the supersolidState is realized even at half - filling, in addition to the well - known supersolidstate discussed in a single layered model   @xcite. by contrast, no such supersolid State has been studied in the bose-hubbard model for the layered curved triangular lattices.. we also discuss the nature of the supersolic states.
supernova remnants ( i.e. remnants of supernova explosions ) are commonly considered to be cosmic particle accelerators.   recent advances in the understanding of these objects have been made through x - ray observations with instruments such as asca, bepposax, xmm - newton and chandra and through @xmath0-ray observations with instrument such as hegra ( high energy gamma ray astronomy ) and h.s. for the detection of very high energy ( vhe ) @x Math0-rays.    this review paper summarises experimental evidence, gathered through@xmath1  ev observations mainly in the vhe regime supporting this notion.
we have searched for distant stars close to the galactic plane using near - infrared data from the eso public survey vista variables of the via lactea ( vvv ), targeting the vvv disk area, which covers galactic longitudes @xmath6 within galactic latitudes.   we have found five classical cepheid variables at distances of 13 - 22 kpc from the galactic center, towards the galactic bulge, that may be associated with the flared atomic hydrogen disk of our galaxy. in   , we review the methods we used to identify these variables, and present the distance and extinction values. as a preliminary search  , we also discuss possible interpretations of the observed values.
the 2010 outburst of xte  j1752@xmath0223 was monitored by the rapid - response evn ( european vlbi newtork ) and the westerbork synthesis radio telescope ( wsrt ).   the transient ejection event was detected by the atca ( australia telescope compact array ) in 2010 january 20, and the transient jet was found to show significant deceleration, possibly due to the jet interaction with the surrounding medium. in this paper   we present results from the additional three epochs of vlba ( very long baseline interferometry ) observations that show a new transient ejectedion event and later a stationary feature which we identify as the core. for the first time  , we show that the proper motion of a transient ejecta detected in one of our earlier observations can be explained by the interaction of the jet with the large - scale medium.
we study a very simple replicator model with a randomly fluctuating growth rate as a model of widening disparity.   we show that winner - take - all phenomena occur in the simplest model, and that the disparity among many elements increases indefinitely even if each element is statistically equivalent. then, we introduce a nonlinear load factor corresponding to progressive taxation and show that disparity widening is suppressed. furthermore, we find stationary equilibrium distributions for the fokker - planck equation.
we investigate two - state discrete time quantum walks ( qws ) in one dimension ( 1d ), which belong to the chiral orthogonal class, interacting with spatially or temporally random defects.   contrary to the previous studies, we reveal that the qws with spatial disorder exhibit delocalized behaviors. this remarkable conclusion is drawn by extensive numerical calculations, and is further ensured by symmetry arguments for the 1d chiral class. here  , we also find that the edge states in the topological phase are robust for spatial disorder but not for temporal disorder.
the rotational states, shape model, and rotational color variations for 107p / wilson - harrington ( also known as ( 4015 ) wilson-harrington ; hereafter 107p ), a representative comet - asteroid transition object, have been obtained by means of numerical simulations and spectral observations.   the results show that 107p is a b - type asteroid with a mean orbit of 2.639 au and a mean diameter of 1.8 km.  in addition, the shape model of 107p has been fitted to the data from the nasa s spitzer telescope and the rotation rate constants of the main - belt asteroid ( mba ) region have been calculated. erythema spectroscopy has been used to study the rotational state, shape models, and color variations of 107 p. the results indicate that 107 p is in a rotational phase with a maximum velocity of 0.9 km / s and a minimum velocity of 3.0 km / sec.    the shape modeling shows that the observed color changes are due to the spin - up by yarkovsky - okeefe - radzievskii - paddack ( yorp ) effects on the surface of 107
the dynamics of evolution depend an organism s  fitness landscape, the mapping from genotypes to reproductive capacity.   knowledge of the fitness landscape can help resolve questions such as how quickly a pathogen will acquire drug resistance, or by what pattern of mutations. but direct measurement of a fitness landscape is impossible because of the vast number of genotypes. here   we critically examine regression techniques used to approximate fitness landscapes from data. in particular, we examine the effects of two inherent biases that distort the biological quantities of greatest interest : ( 1 ) the main effects of loci and ( 2 ) the epistatic interactions between loci. while these biases are known features of most regression techniques, we find that they are not always the result of statistical fits or measurement noise. when applied to the hiv-1 virus experiment, these biases often make evolution appear less predictable than it actually is.see research article http://www.biomedcentral.com/1741-7007/1471-7006/8/9/5/11/10/3
a class of models with quintessence has been proposed where the cosmological constant is replaced with an energy component characterized by the equation of state @xmath14.   the component can cluster on largest scales and therefore affect the mass power spectrum and microwave background anisotropies.  in this paper we generalize the description of the mass functions to include the effect of dark energy with constant@xmath1, which is generally considered to be a function of the density fluctuations at different redshifts. using the mass function of clusters of galaxies at high redshift, we show that the growth rate of the rms density fluctuation and the linear growth factor of the space - time density fluctuations are both constrained by the value of @x Math1. for the model with @x math1,   these constraints are due to degeneracy of the data for clusters at different Redshifts, which can be significantly decreased by using the data at differentredshifts due to different growth rates of density fluctuations in different models.
time delays have been measured for the qso and ly-@xmath8 gravitational lens systems b1422 + 231 and pg1115 + 080 using the low resolution imaging spectrograph ( lris ) at the keck ii telescope on mauna kea.   the results show that the time delay of the system is about 2.5  years, and the redshift of the lensing galaxy is about @xmath6. in addition, the redshifts of galaxies clustered around the lens are about 1.0 , 3.59 , and 4.65  arcseconds, respectively, with a mean distance of ~1.2    0.3   from the lens. these observations are the first to measure the most basic information necessary to exploit the gravitational lenses : the red shifts of the galaxy, the velocity dispersions of the stars within the galaxy near the lens, and its redshift.
the only universal method currently available for computing the probability density function ( pdf ) of the product of two independent random variables relies on a monte - carlo approach, where one samples the individual pdfs, computes the products, and collects enough samples to achieve certain accuracy in the computation of the integral @xmath6 in.   however, due to the slow convergence of such method, achieving high accuracy is not feasible. in this paper   we show how to accurately and efficiently compute the pdf @x math6 in using an approximate multiresolution analysis ( mra ), where the scaling function is a gaussian. by using gaussian - based mra, we demonstrate that, in contrast with the sampling method, our new algorithm is both fast and accurate. while the sample method only provides a histogram of @x Math6, we obtain the result in a functional form that can be used in further computations.
brown dwarfs ( bds ) are objects not massive enough to sustain hydrogen burning in their core and thus to reach thermal equilibrium.   the theory of the structure and the evolution of bds has improved substantially in the past few years and can now be confronted directly to observations and even to laboratory experiments. since a complete review is devoted to giant planets ( gps ), the present one will be devoted to bds. in the present survey,   i will focus on the most recent improvements realyzed in the physics of the interior and the atmosphere of bd and the so - called lithium - test, which provides a powerful independent determination of the substellar nature and the age of a putative bd.
the lindemann criterion describes melting in terms of the root mean square ( rms ) deviation from the atomic equilibrium positions.   we examine two dimensional crystals with properties that would generically be found in two dimensional covalently bonded crystals, including stiffness with respect to displacements perpendicular to the plane of the sheet. although we do not consider temperature regimes capable of disrupting the lattice topology or number of neighbors for each atom, we examine the loss of order caused by fluctuations of atomic positions about their equilibrium positions which nonetheless leave the bonding pattern intact. using the @xmath1-@xmath2 model, we show that the rms deviations from equilibrium converge to a finite value in the thermodynamic limit for suitably rigid lattice geometries, and determine a reference temperature threshold @x Math5 where mean square fluctuations about equilibrium reach one tenth of a lattice constant, corresponding to the melting point according to the lindmann criterion.. however, although we find stable crystalline order in three dimensional geometrie, we also discuss a significant caveat which applies for simple cubic lattices and other geometrical systems which lack local stiffness.
the phase mixing of alfvn waves in coronal plasmas is a well - known mechanism of coronal heating.   the effects of density stratification and magnetic field divergence on the phase mixing are studied in a 2.5d mhd plasma with a uniform background magnetic field. to study the effect of these factors on the damping of the wave amplitudes,   two different solutions of the phase - mixing equations are derived for the polarization of a packet of alFvn packets in a 1.5-mhz magnetic field : the first one is a self similar solution of the hp83 model for the strong phase mixing and the second is a new one for the weak damping approximation. both models show that the amplitude of the waves at low heights follows the scaling predicted by hp83 at high heights, before switching to an algebraic decay at large heights.
we report here the first results on @xmath0 production via electron - positron decay pairs at mid - rapidity from au - au collisions at@xmath1 = 200 gev from data taken during run-2 at the relativistic heavy ion collider at the rhic in 2001.   we find that the yield of @x Math0 is ~20% higher than expected for central reactions at @x maths1 = 17.3 gev and ~30% lower for peripheral reactions.    the observed yields are consistent with the predictions of the glauber model for the nuclear geometry of the collision, which predicts a reduction in the binding energy of the quarkonium states depending on their binding energy and the temperature of the surrounding system.
we report experimental attempt to reduce the width of the zero - field spin - tunneling resonance in molecular magnets by mixing micron - size ribbons of mn@xmath0 acetate with ybacuo grains.   we observe a pronounced magnetic relaxation in the vicinity of zero field and the width is reduced to values as low as @xmath5 oe.
we propose a variance - driven adaptation mechanism for the observed wide variations in the time - headway distributions in congested traffic.   this adaptation is reflected in the empirically observed increase of the variation coefficient @xmath1 and offers a safety - oriented interpretation of the capacity drop, i.e., the significant reduction of traffic flow when traffic flow is perturbed or largely varying. to explain the wide scattering of flow - density data, we introduce the mechanism of variance -driven time headways ( vdt ) in terms of a meta - model which can be applied to a wide range of car - following models. using virtual - detector data from the dutch freeway a9 from haarlem to amsterdam, we show that the vdt mechanism can semiquantitatively explain all the microscopic and macroscopic empirical findings mentioned above. with the increasing availability of single - vehicle data,   further statistical properties of traffic became the subject of investigation such as the velocity variance as a function of the traffic density, or the distribution of the times - to - collision ( ttc ), which plays an important role for traffic safety.
the strong, weak, and electromagnetic interactions  in other words, more or less everything we know about in nature except gravity  are all described by yang - mills gauge theory.   the main idiosyncracy in my presentation is that i have decided to rely on a hamiltonian approach ( including the well - established but relatively unfamiliar notion of Hamiltonian lattice gauge theory ) rather than converting everything to path integrals.. the main problem with the path integral approach is that it is not possible to fully explain the preliminaries in a short space or time, so i have had to seek a middle path. for simplicity,   i will omit the matter fields and just describe the gauge fields.
the local polaron model is a hamiltonian model which has been applied to the problem of resonant tunneling@xcite in the context of electronic transport, and the very similar problem of hot electron femtochemistry at surfaces @xcite ( hefats ).   common to all these applications is that a linear bosonic coupling term has been assumed. here   we examine the consequences of substituting the linear coupling term with a quadratic coupling term. by comparing the inelastic scattering amplitudes of the two models we find that the results are very similar.
the monte carlo  ( mc ) feedback model is used for simulation of decision - making in the stochastic environment.   the feedback is applied to maintain the critical regime of the 2d  ising spin micromodel of ferromagnet and the self - adjusted algorithm is introduced as a random walk of temperature variable biased by feedback that mixes current and past Stochastic signals, originating at the platform of extended statistical system. due to limited memory depth  , the convergence process is necessarily accompanied by uncertainty. since the feedback treats a partial information only, many parallels with risky decisions within the business world can be found. therefore, the mc feedback model may be used for simulations of decision-making in the economic context.
secondary electron emission ( see ) from dielectric and metal surfaces under bombardment of incident electron flux is important for many applications where incident electron energy can reach tens or hundreds of electron volts.   we have developed an analytical model of see of a velvet surface and determined an analytical expression for the secondary electron yield, ( sey, @xmath0 ) of such a surface as a function of the velvet parameters. in this paper  , we also simulated the see process numerically and benchmarked the analytical model against the simulation results. based on the theoretical model, we calculate approximate values of the optimal packing density and aspect ratio of the whiskers to achieve minimum sey as a functions of the primary angle of incidence.
a number of variable - stepsize algorithms for stochastic ordinary differential equations ( sodes ) have been developed and published in the last few years.   we compare the performance of two of these algorithms, sde9 and anise, to that of a previously published method for solving sode problems. both methods yield accurate solutions to a wide variety of stochastically varying volatility models. for one problem   they are found to be hundreds of times faster than the original method.
we have developed a new method for calculating the angular correlation function of the galaxy redshift distribution using photometric redshifts and apparent magnitudes.   this method is based on the galaxy ensemble approach, where we use multiple realizations of the redshift distributions to calculate the appropriate quantity for all of the different ensembles in order to obtain a realistic error estimate.    we show that the obtained results are consistent with the assumed cosmology of the observed data, and that the calculated angular correlation functions are linear in the range of 0.9 to 1.0 for the u band and 0.8 to 2.5 for the b band.,1 the r2 = 0.984, indicating that the measured magnitude errors are small enough to be considered as physical quantities.
recently, the experimental observations of rather strong effect of relatively low frequency microwave radiation on the dissipative conductivity and resistivity of two - dimensional electron systems ( 2dess ) in gaas / algaas heterostructures were reported. to clarify the effect, we provide an explanation associated with the suppression of electron scattering on impurities with intra - landau level transitions by microwave radiation.   the main point is that the ac electric field of microwave ( or optical ) radiation gives rise to spatio - temporal oscillations of the electron larmor orbit center that leads to an additional spreading of the wave function. as a result, the matrix elements of electron - impurity interaction, the probability of electron elastic scattering with a displacement of the orbit center, and therefore, the dissipatives are decreased by microwaves even without absorption or emission of real photons.
the outer region of the and Andromeda galaxy ( m31 ), which is the nearest large galaxy to the galactic center, is the excellent laboratory to examine the prediction of the cold dark matter ( cdm ) model.   however, it is extremely difficult to measure the mass distribution of the outer regions of a galaxy because the stellar and/or gas density is too low to detect even by the latest instruments. in this study, we simulate the interaction between an accreting satellite dwarf galaxy and m31 using @xmath0-body simulations, which especially concentrated on the density profile of the dark matter halo in m31. for the first time  , we show that the density profiles of the inner and outer dark matter halos of m31 with different density profiles are different from each other. in the first profile,   the mass density of the bulge and the disk component of the black hole in the outermost region of M31 decreases with the cube of the distance from the galactic centre in accordance with the predicted cdm model. whereas in the second profile, the mass densities of the stars and the shells at the east and west sides of the giant stream decrease with the square root of the
the applicability of the central limit theorem ( clt ) to systems with long range correlations, at the edge - of - chaos, nonlinear dynamical systems the maximal lyapunov exponent of which is either exactly zero or tends to vanish in the thermodynamic limit ( increasingly large systems ) has been advocated.   we present a detailed study of a paradigmatic _ toy model _ for long - range interacting hamiltonian systems, i.e. the ham Miltonian mean field model.    the model consists of fully - coupled classical inertial xy spins ( rotors ), with unitary module and mass, starting from the same water - bag initial condition with unitarity magnetization. 	 the out - of equilibrium dynamics of the model presents very interesting dynamical anomalies. erythroidic quasi - stationary states ( qss ) are observed in the microcanonical ensemble and the statistical description of the quasiexperimental behavior of the qss is strongly dependent on the initial conditions. here   it is shown that the clt can be applied to these systems, but the applicability is influenced by the different microscopic dynamics observed in each of the three classes of qss.
the dynamics of highly viscous drops in creeping flows with nonzero vorticity are investigated via direct boundary - integral simulations and by using a small - deformation approach.   the results show that the bistable drop behavior is a result of the coupling between the drop shape and the fluid flow. at low frequencies, the drop exhibits a quasistatic behavior, with transitions between the compact and elongated stationary drop shapes occurring at different values of the vorticicity. at high frequencies the drop undergoes a much more complex behavior, where the drop response to the periodic forcing is chaotic. as expected, the chaotic behavior of the drop stems from the existence of two stationary states observed in steady flow. for the system considered in our study,   both the hysteretic and chaotic drop behavior are associated with the presence of rotational and capillary stabilizing forces on the drop surface.
non - local correlation of quantum states is a fundamental property of quantum process, and to restore the motion of particles back to deterministic manner is in fact impossible.   nevertheless, one may ask a further question : is such kind of non -Local correlation globally correlated or partially localized? from a point of view of standard non - relativistic quantum mechanics, since wave function is defined on the whole space, as well as all operators, the theory must be globally correlated. in terms of feynman s path integral formalism, that is to say that when calculating the transition function between two quantum states @xmath0\mathcal{d} \nonumber\\ & & \times \exp\left, \label{eq
the main purpose of our work is to consider space domains with the deformed small extra dimensions as dark matter particles.   we study various stationary geometries of the two - dimensional sphere type, and find that the lagrangian we consider is a nonlinear function of the ricci scalar that allows to stabilize the extra space size. in particular, we show that every point of a domain of the three - dimensional physical space has two compact extra dimensions with the extraspace geometry differs from that of the ideal sphere.. such a domain has an extra vacuum energy, i.e.  it can be considered as a dark matter particle.    we estimated the vacuum energy density as a function of this extra space deformation. 	 we also discuss the cross section of such domains of small size interacting with particles of the ordinary matter.
hot molecular cores are small pockets of warm ( @xmath1  k ) dense molecular gas near stars of all masses, which form the majority of known hot cores.   they are formed by internal heating of the star's natal molecular clouds and are characterised by large abundances of complex organic molecules such as ch@xmath6och@x Math6ocho masers, which are thought to be the chemical ` daughter'products of reactions of evaporated ice mantle components, their'parents '. in this review,   we summarize the current knowledge on the chemistry of hot cores, with an emphasis on recent developments.
the formality of the _ framed little 2-discs _ operad @xmath4 is proved by kontsevich, tamarkin, severa, willwacher, and wahl using braid groups and drinfeld associators.   the proof is algebraic in nature, using quasi - isomorphisms which are homotopic for a particular choice of drinfeld associatesator. here   we show that this proof is compatible with the cyclic structure of the operad@xmath17, which is constructed in terms of compactified moduli spaces of genus zero curves with marked points.
regge calculus is used to re - examine the formation of apparent horizons in a particular class of brill wave spacetimes, and to confirm recent numerical findings regarding the appearance of such horizons.   we find that in both the regge and continuum solutions an apparent horizon first appears at a critical amplitude @xmath4, which lies in the range@xmath5 $. as the amplitude of the brill wave increases above this critical value, two trapped surfaces are present, and these gradually separate. using a simplified trapped surface finder for regge calculus, we show that the initial data constructed here are in excellent agreement with previous calculations by holz and alcubierre.
luminous blue variables ( lbvs ) are spectacular examples of variable stars, which can brighten by orders of magnitude on timescales of months to years.   these stars are typically more evolved than the @xmath1 ceph stars, and undergo periods of outburst, typically characterized by enhanced mass - loss rates. during these events, both the temperature and the luminosity of the star increase, typically by 1 - 3 bolometric magnitudes. in this work, we focus on the intermediate type of variability, known as microvariability, which is small, typically a few tenths of a magnitude.. we investigate radial pulsation as a possible origin for the variations, although nonradial pulsations may also play a role.    we find that the frequency of the variations is highly variable, ranging from 0.2 to 2.0 per year, and that the duration between outbursts varies from weeks to months. using a combination of spectroscopic and theoretical techniques, we show that the observed variations are caused by radial pulsations, with the rate of pulsation being the most important factor. at the time of the peak of the variation,   the star is at the top of
the evaluation of definite integrals has been a problem of interest to scientists since integral calculus was developed.   the method proposed in this paper is a new addition to the methods for the evaluation of these integrals. given a formal sum @xmath18 we associate to the integral of @x Math19 a _ bracket series _ written as @x math20 to keep in mind the formality of the method described in this article. given an index @xMath22, the index will be replaced by a number@xmath23 defined by the vanishing of the bracket.    the present method is based on the assignment of a bracket to any parameter @x maths16 and the definition of a divergent integral @x mathematics17 using the concept of a   bracket - like symbol. the formal rules for operating with these brackets are described in section  and their justification is work - in - progress.
the problem of work extraction from two systems at different temperatures @xcite by coupling them with a reversible work source is discussed in this paper.   it is assumed that internal energy of each system is determined by the difference of initial and final energies, and that the process is thermally isolated in which thermodynamic entropy of the total bipartite system is preserved. to extract maximal work,   the processes are assumed to be thermally isolation in which both systems are brought back to their initial states by separating them from the work source and making contact with thermal baths at temperature @xmath0 and@xmath1 respectively.    we propose a definition for effective temperature of the composite system, which is calculated explicitly in different regimes of parameter values. here  , we define an effective temperature for the passive state of the quantum heat engine using two two - level systems ( tls ) and analyse its properties.
we show that a dipolar bose - einstein condensate is metastable against local collapses even far from the stability boundary.   we develop an analytic model in which we consider sharp density spikes ( i.e.  a local collapse ) forming on top of a condensates, and use the gross - pitaevskii equation to quantify the energy barrier to collapse. by extending the sgpe formalism @xcite to include the magnetic dipole - dipole interaction ( ddi )  , we show that the system is thermally activated when the dipole interactions are stronger than the short ranged contact interaction. using a finite temperature dynamical model for the system, we demonstrate that the local collapse events are thermally active and support our density spike model.
the sunyaev - zeldovich ( sz ) effect is a strong correlation between the x - ray power and the radio power of galaxy clusters.   it is also a robust indicator of cluster mass, irrespective of cluster dynamical state, and can be used to find radio haloes in late mergers and other massive systems which are left out in x -ray selection. here   we present the first radio - sz correlation for clusters with giant radio Haloes, which are diffuse sources of radio synchrotron emission extending over the @xmath1 mpc scale. using the planck    all - sky cluster catalog, we show that the sz signal is strongly correlated with the radio energy of the intra - cluster medium ( icm ) in clusters harboring these haloes, and that this correlation is more robust than expected based upon the observed scaling between radio power and sz.    the results are consistent with the model that the heating of the icm by relativistic particles is driven by collisions between cosmic - ray protons and thermal protons during cluster mergers, and suggest that the concordance between the two models is not as strong as previously thought.
we study the endomorphism rings of the maximal rigid objects of a cluster category @xmath2 defined from a different hereditary abelian category, namely the cluster tube.   we find a description in terms of quivers with relations for the algebras we consider here, and use the technique from @xcite to show that the gabriel quivers are self - injective. since the endomorphic rings are gentle, they are string algebrae, and we use the theory of string- and band - modules to show them to be of finite type.the paper is organised as follows : section  contains the definition of the cluster Tube and a description of maximal rigid object recalled from @xaicite. in section  we give the description of the endorphism rings, before we study the gentleness and gorenstein dimension and give some facts about indecomposable representations. in sections  and  we describe the action of the hom - functor.
the gravity probe b ( gp - b ) satellite is scheduled to fly in the year 2000.   it contains a set of gyroscopes intended to test the predictions of general relativity that a gyroscope in a low circular polar orbit, with altitude @xmath3, will precess about 6.6  arcsec / year _ in the orbital plane ( geodetic precession ) and about 42   milliarcsec/year _ perpendicular to the orbital planes ( lt precession).in this paper   we review the theoretical derivation of these effects and in particular consider the contributions of the earth s quadrupole and higher multipole fields. using the standard linearized general relativity ( lgrt ) approach we show that the metric of a rotating body contains no * new * fundamental parameters. for any scalar and vector potential field in a general weak field system, that is for any body rotation up to the order@xmath4, the precessions of the gyroscopes depend only on the tensor of inertia of the ground state. however, the contribution to the lense  thirring precession is beyond the expected accuracy of gp-b and close enough to the
small - scale scalar anisotropy is observed in many experiments in the turbulence of the atmospheric surface layer and grid turbulence.   these observations challenge the kolmogorov cascade phenomenology for the transfer of scalar - variance from large to small scales, and directly affect modeling for large - eddy simulations ( les ). here  , we show that the isotropy level of the subgrid - scale ( sgs ) strain - rate tensors and scalar gradient can be probed by measuring the isotropic levels of the tensors at different scales.. the results show that even though the mean sgs dissipation rate is generally equal to the molecular dissipation rates, the values of the sgs kinetic energy dissipation are not always equal to those of the scalar Dissipation rate. on the other hand,   the mean scalar variance dissipation does not follow predictions from isotropy at inertial and dissipative scales when the flow is in equilibrium. as a function of scale, the difference between the two scales is more or less isotropical depending on the size of the diffusivity of the solution, and this difference is most pronounced at the small scale.
we introduce a method for computing the norm of a foguel operator.   moreover, we are also concerned with the spectral analysis of the modulus of a bounded operator. in this note, we consider the case of a complex symmetric complex hilbert space defined by a conjugation of the operator @xmath9 with respect to which @x Math9 is a complex - symmetric operator if and only if @x math9 is unitarily equivalent to a symmetric matrix with complex entries. using this approach,   we prove that many foguel operators ( including foguel - hankel operators ) are complex asymmetric.. moreover, it turns out that many questions concerning the norm and modulus can be reduced to the complex symmetry case via a block matrix argument.
we investigate the low - energy dynamics of chirally symmetric models with a short range interaction in an external magnetic field.   we show that the effect of the magnetic catalysis of chiral symmetry breaking depends on the sign of one particular moment of the coupling constants, which we denote by @xmath0. for strong external magnetic fields and short ranged interactions,   this is very natural in 2 + 1 dimensions where the modes of the lowest landau level are non - propagating, and in the absence of interactions, the ground state is highly degenerate and can be divided into both chiraly symmetric and chirly non - symmetric states. even with infinitesimally small coupling constants  , these degeneracy states will be split, and the dynamical generation of parity violating masses seems to be suppressed by magnetic fields. in the more complicated case of ( 3 + 1)-dimensional gauge theory, we argue that the infrared dynamics is governed by an effective ( 1 + 1-dimensional ) gross - neveu like theory with an infinite number of flavors of fermions. using the renormalization group, we derive the most general low energy effective action which is compatible with the
many natural and engineering systems exhibit transition from one state to another.   some of these transitions are continuous, i.e., the order parameter grows smoothly from zero to zero as the control parameter is increased, while some others exhibit a discontinuity or a finite jump in the order parametrization. among these transitions,   the former class of transitions is called supercritical, while the latter is called  subcritical. " magnetic field generation or dynamo process in astrophysical plasmas and in electrically conducting fluid interiors of planets and stars exhibits transition from no - dynamo or fluid state to a magnetic state  . this transformation is referred to as  dynamo transition " ; several laboratory experiments have replicated this process in controlled laboratory experiments and report supercritical transition, whereas numerical simulation and models exhibit both supercritical and subcritical transitions. in this paper  , we explain these transitions using several low - dimensional models.
the properties and phenomena arising from the interaction of a bulk elementary superconductor ( sc ) and magnetic nanostructures grown on top of it were investigated by scanning tunneling microscopy / spectroscopy ( stm / sts ).   the main goal was to prepare a clean ta(110 ) surface and to grow sub - monolayer coverages of fe2 + nanoparticles on top. in order to identify the main source of contamination,   auger electron spectroscopic and low energy electron diffraction investigations were carried out at room temperature and 37  k. the results show that the main contamination source is oxygen, which is dissolved in the bulk, but can be reduced if further annealing cycles are performed at 2500  k for 10 min. after this time period, the surface morphology is much more flat exhibiting parallel step edges and domains, that vary in their angular orientation. as a result, the observed morphology resembles characteristic patterns, which have been assigned to an oxygen induced surface reconstruction in case of nb / nbo - type superstructures   @xcite. however, the influence of carbon and oxygen contamination on the structure of the hybrid system is not well understood.
we revisit the use of chirally mixed spectral functions in both the weinberg - type sum rules ( ws ) and the finite - temperature sum rules for quantum chromodynamics ( qcds ) utilizing updated vacuum spectral functions  @xcite and numerically evaluating the consequences of finite pion mass corrections.   we find that the degenerate continuum in vector and axial vector channels and quantitative agreement with the @xmath0-decay data, as well as the qcd sum rules, are important in a quantitative low - temperature analysis.
phase transitions in heavy ion collisions at intermediate energies have been a topic of considerable interest since the mid - eighties.   there are many approaches and a large literature too numerous to list but we will refer here to only a few which closely follow the underlying physics considered here. by extrapolation   it was shown that the model used in @xcite leads to a first order phase transition as either the density or temperature is varied. for large systems,   a scaling law for composites emerges : if we know the yields of composites for one large system, we know these for another large system.
polariton condensates are produced in a semiconductor microcavity using non - resonant excitation.   the system is controlled by optically - induced tuneable repulsive potential barriers, which block propagation of the propagating condensate wave trains. under these conditions,   polaritons are confined into a coherent ground - state, which can be used as a logic gate for the formation of new ultrafast, non - linear switches.
fine tuning @xmath6 is a measure of the probability of unnatural cancellations between soft susy  breaking terms in the determination of the electroweak breaking scale after including quantum corrections and experimental constraints.   the measure determines the cancellation needed between the independent terms contributing to the symmetry breaking vacuum expectation value and provides an intuitively reasonable way of quantifying fine tuning. as we shall discuss  , the fine tuning measure allows one to quantify the significance of individual measurements in testing susy over the full parameter space and so is useful in correlating the various measurements relevant to susysearches.
we study the @xmath0-mode characterized by regular eigenvalue problem for large class of polytropic and non - isentropic relativistic stellar models.   we derive the basic equation for the pure @x maths 0-mode in relativists.    we find a solution for the regular eigenevalue problem with a continuous part of frequency for the rotational mode whose eigenfunctions are composed of only one axial parity component in the non - rotating star limit, which is consistent with the results obtained by kojima ( 1998 ).
we present a new model of the evolution of stellar mass from low - mass to intermediate- and high - mass stars.   we find that the first dredge - up is practically absent in all models, and that the surface composition is enriched almost only in he and negligibly in cno elements. with the adopted prescription for mass - loss,   stellar winds are never able to strip off h - exhausted layers in models with @xmath17.
the acceleration and collimation of powerful bipolar outflows and jets in a variety of astronomical settings are often attributed to the action of magnetic fields.   the most general semianalytic solutions obtained so far have been time - independent and self - similar, patterned after the pioneering disk - outflow solutions of @xcite. here   we further generalize these solutions to the " hot " relativistic case  i.e., we allow both the bulk _ and the random speeds to be relativism. this is motivated primarily by the desire to apply them to gamma - ray burst ( grb ) outflows, in which thermal driving by an optically thick, hot " fireball " composed primarily of radiation and electron - positron pairs could play a role. for this purpose, we present a new model of grb outflows in which the bulk and random speeds are relativistically fast and that the thermal pressure plays a negligible role in the flow acceleration and by the flow being trans - alfvnic : the poloidal speed at the base of the flow comes to exceed it further up. using the new model, we show that the energy deposited by the fireball into the source can be fully accounted for
qcd at finite temperatures ( @xmath0 ) and/or chemical potentials (@xmath1 ) is of fundamental importance, since it describes particle physics in the early universe, in neutron stars and in heavy ion collisions.   there are well established nonperturbative lattice techniques to study this transition at vanishing density. due to the sign problem   nothing could have been said for almost 20 years about the experimentally important case at nonvanishing densities. in the last year   new, and for the first time successful approaches appeared and physically relevant results were obtained @xcite.the aim of this review is to give a self - contained picture on the lattice approach at @x Math1@x math30 for real qcd.    the qualitative features of the phase diagram are summarised both at @ xmath1=0 and @x maths1@Xmath30. 	 the main emphasis is put on the origin of the problem and technical details are not discussed. in section 4 the two new techniques ( the overlap improving multi - parameter reweighting @xaite and the analytic continuation @xfite ) are presented. in sections 2 and 3   the results of the
a great challenge in modern times is the construction of predictive theories for nonlinear dynamical systems for which the evolution equations are barely known, if known at all.   a universal law should hold for different systems characterized by different models, but leading to similar basic parameters, like the critical exponents, depending only on the dimensionality of the system and the number of components of the order parameter.the fractal geometry is a perfect framework for studies of stochastic systems which do not appear at first to have underlying scales. here   we review the main features of the fractal - like exponents obtained from different techniques, and discuss how they are measured, and what basic differences exist between each one. some technical materials can be usefully found in @xcite.
we present the most comprehensive and precise experimental results to date for all transitions within the multiplet associated with the line @xmath71153.   lifetimes for the three values of @x Math16 in the upper fine structure levels of the multi - level multiplet @x math71154 were obtained from beam - foil measurements of the decay curves of all transitions between 3@xmath1 @x maths2 and 3@Xmath44@xmatrix5 @xMath6. we ascribe the weaker and longer - lived decay to a cascading transition that repopulates the upper level of interest at 1154 , which is the strongest in p  ii and is in a relatively clean portion of the spectrum.    our results are presented and then discussed after we describe the experiment.
we present a quantization scheme for the field strength on an arbitrary four dimensional globally hyperbolic spacetime within the framework of the algebraic formulation of quantum field theory.   we show that the commutator between two generators of the field algebra of observables is given by the lichnerowicz propagator @xcite regardless of the chosen spacetime. in particular, we prove that it is not possible to reconstruct all field strengths fulfilling maxwell s equations on a flat background, even starting from an auxiliary object such as the vector potential @xmath1, but only those which are poincar invariant and thus diffeomorphic to the spacetime@xmath2.. this result has far reaching consequences since it tells us that, if one wants to quantize maxwells equations on curved backgrounds, unless @x Math2 is somehow special, one cannot use @x math1 as the building block, albeit it is the real observable.
the efficiency of a quantum thermal engine at maximum power is studied.   the model is based on einstein s theory of radiation, in which the heat transferring process between the working substance and the heat reservoirs is governed by the heat transfer law. for this model, the temperature differences between the heating and cooling stages are fixed and the adiabatic expansion and compression processes are reversible. under these conditions,   we derive the formulas for the heattransfer and entropy production, and find the upper and lower bounds for the efficiency at maximum energy in the long and short contact time limits respectively.
the search of the @xcite all - sky monitor ( asm ) for periodicities in the intensities of x - ray sources using light curves obtained over a longer course of time, i.e., nearly 14 years as opposed to 8.5 years, has been extended.   the search is based on the analysis of light curves produced by the _ rossi x - rays timing explorer ( rxte ) _ all -sky monitor ( @xmath0 ) using data acquired from the asm during the mission - long period 1996 through 2010. among the 571 potential sources that have been observed by the asms over the 14 years of operation in orbit,   five possible periodicities or quasiperiodicities have been identified : @x Math1, @x maths2, @Xmath3, @ymath4, @Ymath5, and @x math6.    the search was conducted using data from the first 8,5 years of the@xcite mission which were analyzed using the same analysis techniques as those used in the earlier search.  one of the major improvements in the sensitivity of the search compared to the previous search was the use of light
support vector machines ( svms ) are widely used in high energy physics ( hep ), with the current standard version proposed in 1995  @xcite.   they aim to classify data points using a maximal margin hyperplane mapped from a linear classification problem to a possibly infinite dimensional hyperspace. however this means svms have a number of free parameters which need to be tuned on a case by case basis. in this paper   we present a generalisation of the hard margin support vector machine algorithm that uses a kernel function to map the problem from the input space to a potentially higher dimensionality, implicit feature space, where the data may then be separable. as an example of how this can improve performance   is given, we show how it can be used to improve the performance of the checker svm algorithm for handwriting recognition.
recently simon et al.   have published hubble function @xmath0 data extracted from differential ages of passively evolving galaxies. in this paper   we use them in combination with the latest sne ia set and the cmb shift parameter as calculated by wang and mukherjee @xcite to constrain the background evolution of six different cosmological models that show late - time acceleration. for all of them we have assumed flat space, consistent with the inflationary prediction that the curvature density parameter@xmath2 and the results obtained by cmb experiments @xaite can be used to test non - lcdm models. using these data, we have chosen to put constraints on 6 different model types : dark energy, non - self - accelerating, and two chevalier - polarski - linder parametrization models ( qcdm and dgp ) and a phenomenological extension of the ldgp model ( qdgp ). at least three of the models are dark energy models while in the remaining three the acceleration arises from or is modified by a five - dimensional modification of gravity motivated by extra dimensional physics.    we have used the same data to
we study the relative computational efficiency of the frequency domain ( fd ) and time  domain ( td ) codes for the solution of the inhomogeneous teukolsky equation.   specifically, we study the question of how much computational time is needed to find the fluxes of energy and angular momentum to infinity from an eccentric and equatorial orbit around a fast spinning kerr black hole around a supermassive black hole using the fd and td approaches. in order to achieve this goal  , we estimate the number of azimuthal modes required for the total sum over @xmath0 modes to achieve the desired accuracy level of @xcite, and compare the results obtained by the two approaches. as expected, the computation time for the td approach is significantly faster than that for the Fd approach, but the difference is not statistically significant.
reliable determination of total mass of spiral galaxies is a crucial step in the search for non - baryonic dark matter.   present models of mass distribution in spiral galaxies assume that in addition to stellar disk, bulge, luminous halo, there is massive halo of non-baryonic black matter, most often assumed spherical, which dominates the total galaxy mass and also governs the dynamics of outer parts of the stellar disk. here   we show that for some spiral galaxies it can not be spherical at larger radii. since we expect in this case a flattened mass distribution to better approximate the gravitational potential at large radii than the spherical one, we apply the global disk model. using this model, we find that mass distribution of luminous matter accounts for rotation curves of the examined galaxies.. these results need to be seen properly in the context of non - Baryonicdark matter searches.
the completeness of a quasar survey should be specified by the survey selection function, @xmath8, which gives the probability of detecting a quasar as a function of absolute magnitude, redshift and spectral energy distribution.   we use a statistical method to estimate the completeness in terms of the total population of quasars that can be found in an area of sky surveyed by two or more different techniques. using a sample of objects derived from a known parent population, we show that the total number of objects in the parent population is satisfactorily recovered.
in recent years, there has been an increasing interest to link the discussion about complex phenomena in natural science, such as physics or biology, in particular to those in life science, including economics, sociology, economy or regional planning.   this paper aims to contribute to this discussion by adapting a model of interactive structure formation, which has already proved its versatility in a variety of applications, to the problem of economic agglomeration. using agent models, which have originally been developed in the artificial life community,   the current paper focuses on an agent based dynamics of economic concentration.the agent model is based on active brownian particles, which can be regarded as an autonomous entity with either knowledge based or behavior based rules @xcite, performing complex actions, like bdi ( belief - desire - interactions).the results show that the agent model can be used to study the spatio - temporal pattern formation of economic structure formation in a stochastic dynamical theory, and it is shown that the emergence of new economic centers and the global competition of existing economic centers can be considered as two different processes, which are closely related to the evolution of complexity.
the evaluation of the curie temperature of diluted magnetic iii - v semiconductors ( dms ) with curie temperatures ( @xmath0 ) in the range of the room temperature is still a challenging task, in particular for complex alloy systems like the dms.   conventional approaches known from model studies @xcite can not be directly employed for evaluation of @x math0. here   we present a new approach based on the adiabatic treatment of atomic moments in the framework of the local spin - density approximation ( lsda ) hamiltonian to evaluate the temperature - dependent properties of dms at the level of the ground state using the real - space approach. by means of this approach   the total energy of the perturbed ground state is mapped onto a classical heisenberg model whose statistical treatment is further simplified by using the magnetic force - theorem@xcite which allows to use the band energies of the calculated ground state as a good estimate also for total - energy differences of the probed ground state.. the separated treatment of statistical degrees of freedom of the parametrization results in a more tractable and accurate method for the evaluation of # xmath0.
abstractthe current picture describing launching and acceleration processes of relativistic jets in active galactic nuclei ( agn ) attributes a key role to magnetic fields, by means of which the energy stored in a rapidly spinning ( kerr ) supermassive black hole ( bh ) can be extracted and channeled into a poynting flux.   dissipation of part of the kinetic ( through shocks ) and/or magnetic ( through reconnection ) power leads to the acceleration of particles up to ultra   relativistically energies, producing the non  thermal emission we observe from the jets of  blazars _, i.e. radio  loud agn with a jet closely pointing toward the earth. here   we review the evidence for the existence of sub - equipartition magnetic fields in the jet at large scale, and discuss the implications of this finding for the current model of the accretion of matter from the bh.
@xcite studied star - formation processes in low - mass molecular cloud cores using one - dimensional ( 1d ) spherically symmetric hydrodynamic simulations.   a transient, quasi - hydrostatic object is formed in the early phase of the proto - stellar collapse, a so - called first ( adiabatic core ), which evolves via accretion from the natal core and it collapses again when it attains a temperature high enough to dissociate hydrogen molecules. although first cores are transient, they are essential to understand star formation processes because they assume a crucial role in the two major problems in the star formation process, the angular momentum and the magnetic flux problem. here  , we discuss the observational properties of first cores that have been predicted on the basis of 1d radiation hydrodynamics simulations and post - processing radiation transfer calculations by using the results of 3d hydrod dynamic simulations with barotropic approximation @xcite.
we describe a new low - complexity architecture for multi - input multiple - output ( mimo ) channels that can achieve significantly higher rates of decoding than existing solutions of similar complexity.   the proposed approach is based on the recent insight that if on all transmit antennas, the same linear or lattice code is used, then it is possible to not only decode codewords themselves, but also integer linear combinations of codeword pairs directly @xcite. in order to illustrate this concept and motivate the proposed new approach, we consider the standard mimo channel and develop a new _ integer - forcing _ linear receiver architecture that provides multiplexing and diversity gains over traditional linear architectures.
asteroseismology is a very powerful tool in the study of exoplanets.   this is because we can measure the frequencies of the stellar oscillations to a very high accuracy, and the oscillations can give us information about the stars that we cannot otherwise measure, helping us to constrain better the stellar parameters. in the last few years   we have seen quite a breakthrough in results, which indicates the great potential of asteroseistology as a tool in relation to the search and studying of ex planets.
the abraham - minkowski controversy is a century - old problem which debates that the momentum of a photon in the optical media is either on - shell or off - shell.   this article is intend to solve the off - Shell propagating behavior of photons in atoms during the photon - atom scattering processes using the bound - state quantum electrodynamics ( qed ) model. for the first part of the paper, we present the s - matrix formalism of bound - states qed for the photon- atom scattering process and give the origin of photon s off - shells behavior in atoms by studying the feynman propagator of the light - atom(ion ) scattering process.. then, we study the propagation behavior of the refracted photon from one point to another in atoms with the Feynman propagateator and its off - shapiro - riegerlich method based on the quasiexperimental theory of quantum field theory ( qfft ).    the results show that the feinman propagators of the scattering process are the same as those of the non - relativistic light -atom(ion) scattering models, but they are different from them due to
we propose a new version of the grw model of wavefunction collapse, which is both local and lorentz invariant.   it is shown that the collapse takes place along the forward light - cone from the point where the particle is in an eigenstate of momentum, and that the effect of a given hit on the particle depends on the distance from the hitting point to the point on the light -cone from that point. for a free particle, we constrain the particle to a single spatial dimension ( z ) and take the wavefunction to be a solution of the klein - gordon equation. as a result  , we obtain a local analogue of the collapse model @xcite, which shows that the effects of hits occur in a local fashion, and are not affected by the space - time coordinates of the hitting points.
the post - agb phase is a short period in the evolution of low- and intermediate - mass stars between the asymptotic giant branch ( agb ) and the planetary nebula ( pn ) phases.   many significant changes occur during this phase to both the star and the nebula, resulting in the formation of diverse, axisymmetric, nebulae. here   we present an @xmath3 snapshot survey of post - Agb objects by increasing the range of masses and chemical composition ( c / o ratio ) and by enlarging the distance between the central star and its nebula by 1.5 m from the nearest near - infrared ( nir ) source. using the newly obtained data, we show that the main cause(s ) of the breaking of mass - loss symmetry observed in the post - AGb phase are the expansion of the outer circumstellar envelope and the presence of asymmetrical structures around the center of the centralstar. among the different morphological classes of these structures,   the most interesting ones are the star - obvious low - level elongated ( sole ) and dust - prominent longitudinally extended ( duplex ) types which show star - dominated emission
the contribution from the mass mechanism to the @xmath1 decay amplitude is compared with the long - range contribution from lepton number violating operators.   we decompose all @x Math0@xmath2 operators and determine the level of perturbation theory, at which the different decompositions ( or " proto - models " ) will generate neutrino masses. for tree - level, 1-loop and 2-loop models, the short - range part of the decay amplitude   is most important, while for 2- loop and 3-loop model the mass mechanisms are dominant.
we derive and numerically solve the equation of motion for the density derivative of the self - intermediate scattering function within the mode - coupling approximation @xcite and present numerical solutions of this equation.   the latter equation is essentially identical to that for the long - wave vector limit of the three - point susceptibility introduced by biroli, berthier, and berthier et al. in a recent paper on the dynamics of a glassy colloidal suspension, we show that the time and wave vector dependence of the density derivatives of the collective ( i.e. _ collective ) and self - intermolecular scattering functions are very different. while the collective part of the multi - point dynamic density correlation function is generally considered as the full four - point function, in computer simulations usually the self part of this function is monitored via the so - called irreducible memory function, which is defined as the inverse of the diffusivity coefficient of an isolated brownian particle with respect to the number of interacting brownian particles. here   we consider the simplest possible model of a colloidal system : a system of interacting Brownian particles at different densities. using the differential equations for the diffusion coefficient and the direct correlation function
the low - mass microquasar gx 339 - 4 was discovered in 1972 by the satellite oso7 ( markert, canizares & clark 1973 ).   it has been extensively observed at all wavelengths from radio to x - rays, and detected in all the canonical spectral states of x - ray binaries. however, little is known about the remaining characteristics of the binary system. here  , we show that the power - law spectrum of gx339 - 4 during the low - hard state of its emission is explained through compton up - scattering of accretion disc photons by hot electrons in the corona of the donor star, which is generally thought to be a black hole. using a combination of optical and radio spectroscopic techniques, we have measured the absorption lines of the compact object at @xmath15 kev for the first time on the scale of the continuum of the k@xmath14 line superimposed on the power Law of the universe. as a result, we find that the density of the companion star is lower than expected, and the mass of the secondary star is close to the lower limit of the proposed mass of a stripped - giant. this suggests that the source
we present a network - based approach to determining when discrete - space chemical reaction systems may exhibit an extinction event.   we demonstrate the effectiveness of corollary  on several models, including a model of the envz - ompr signaling pathway in _ escherichia coli and a stochastic petri net model of continuous time markov chains. by relating the topological properties of a network s reaction graph to its admissible qualitative dynamical behaviors, we show that a chemical reaction network with a discrete state space exhibits an extinction events if there is a modified network, called the domination - expanded reaction network, on which a particular set of inequalities on the edges can not be satisfied.. the results are compared with those of previous work using the deterministic ordinary differential equations for the model @xcite.
the effects of string theory on gravitational physics are usually investigated by means of effective field theory actions, obtained through a perturbative expansion in the string tension @xmath0. at the tree level  , the effective action of the heterotic string contains a coupling of the dilaton with gravity via the term @xcite.   it turns out that the model admits solutions with non - trivial dilatonic hair. in this paper   we investigate if a similar phenomenon can occur in the purely gravitational sector. since we are mainly interested in showing the existence of primary scalar hair in the scalar - gravity sector, we consider a simplified model with a dilaton and a unique modulus which couples exponentially with the term. to our knowledge   no investigation has been devoted till now to its implications on physics.we find that in fact the qualitative features are similar to the case of maxwell coupling. also we find that an upper limit must be imposed for given mass, in order to avoid naked singularities.
the electronic transport properties of single - helical proteins are studied in terms of the effects of environment and helical symmetry.   we propose a model hamiltonian to explore electronic transport through single -helical proteins and compare our results with another model proposed in ref. here  . we study different transport properties from localization behaviour to i - v response including the effects on electron spin polarization of the protein molecules based on the disordered on - site potential of the amino acids within the tight - binding framework. using this model, we show that due to presence of multiple charge conduction pathways ( mccp ) along the helix, electrons face less disturbances / environmental effects during conduction and transport characteristics will be much rigid ; reproducing experimental results will bemuch simpler with them.
bose - einstein condensation ( bec ) in a dilute alkali atomic gas opens up new perspective in the field of many body physics.   most of the properties of these dilute gas can be explained by considering only two - body short range interaction which is characterized by the s - wave scattering length @xmath2@xcite. recently, a new kind of atomic bec has been proposed by d. odell _ et al. here  , we obtain the excitation spectrum of a gravity - like self - bound bose gas by using the time - dependent variational method. to give an analytic expressions for collective excitation frequencies, superfluid coherence length and critical angular frequencies required to create a vortex of a rotating bose condensed state, we compare the results of the tf - g regime with the results obtained in the tf regime of an ordinary atomic bec.
the black hole x - ray binaries ( bhbs ) of h  1743322 and ic  x1 show a variety of quasi - periodic oscillations ( qpos ) that appear as peaks of small but finite widths in the power density spectra.   these qpos can be grouped in three categories  high frequency qpos that occur in the frequency range of @xmath10 and are generally transient, low frequency Qpos ( lfqpos ) in the range of@xmath12 @xcite, and very low frequency q posit(s ) that have been observed in the heart - beat sources grs  1915 + 105 @xaite and igr  j170913624. here   we discuss the evolution of black hole transients in the soft intermediate state ( sims ) and the transitions between these states in the presence of thermal accretion disk emission from the black hole.
we present a new method to estimate the primary contribution of electron and positron fluxes in the interstellar medium ( ism ) to the total amount of cosmic rays at @xmath1 gev.   the local interstellar spectrum ( lis ) for the different species of particles using the galprop code @xcite is used to calculate the fluxes and ratios of electrons and positrons in the ism from the observed data of the ams-02 collaboration, which confirms the positron excess in cosmic rays. by using the diffusion equation@xcite we find that the energy density of the particle as a function of the time depends on sources e.g. dark matter or pulsars and their nebulae.
the baryon acoustic oscillations ( bao ) produced by the interaction of photons and baryons in the early universe provide an absolute standard rod that is calibrated by observations of the cosmic microwave background.   they are complementary to other probes of the universe s geometry, such as supernova measurements of luminosity distance, in that they measure different cosmological properties and have a different physical basis ( and therefore have different sources of systematic errors ). at low redshift,   bao yield a measurement of the distance scale that requires only the cmb calibration of the sound horizon scale and is largely independent of the details of the Cosmological model ( @xcite ). using the 6df galaxy survey ( 6dfgs )  , we measure the correlation function of the bao scale for a sample of galaxies selected from the 2mass extragalactic source catalog covering the whole southern sky outside of 10@xmath12 from the galactic plane with the uk schmidt telescope operated by the australian astronomical observatory ( aao ) over a wide range of redshifts from 10 to 190. the results show that the measured correlation function is robust to the effects of non - linear clust
hyperon - nucleon and hyperon - hyperon coupling constants derived from su(6 ) quark model for vector and isovector meson sector.   hyperon couplings to scalar mesons were fitted to reproduce experimental data for hypernuclei and double hypernuci ( see the next section for more details ), and the results indicate a strong influence of cross interaction on the density dependence of symmetry energy.
heat and work are two types of energetic resources, one fully controllable and useful, the other uncontrolled and wasteful.   an impressive effort has been devoted to providing a consistent mathematical characterisation of these notions within a quantum mechanical description of physics @xcite. in this paper   we focus on the _ mean  values of heat and work where the analysis simplifies but still requires careful thought. while the first law of thermodynamics states that the sum of the two average energy types is the average internal energy, @xmath8 defines the second law as the change in a system s entropy that is larger than the average heat absorbed by the system during a process. using the non - equilibrium work relation as a model system, we show that the infinitesimal difference between the mean heat and the mean work of a system can be obtained by considering the time evolution of the system which brings its density matrix from@xmath1 to @x Math4 while the hamiltonian varies from @x math2 to @Xmath5.. the results are compared with the results of previous studies that have used quantum trajectory approaches to characterise the relationship between heat and Work.
quantum communication via telecom fibers is still limited to around a hundred of kilometers due to fiber losses and noisy detectors.   one way to overcome this limit is the use of entanglement swapping @xcite, e.g. in a quantum relay configuration as proposed in @xmath0. here   we present an experiment proving the feasibility of a partial bell state measurement ( bsm ) over two times 25 km of optical fibers. by using a periodically poled lithium niobate ( ppln ) waveguide, we create two degenerate photons at 1550 nm by spontaneous parametric down - conversion ( spdc ) in a nonlinear crystal. in order to increase their coherence length, their initial spectral bandwidth of 80 nm   is filtered down to 0.8 nm ( 100ghz ), corresponding to a fourier limited coherence time of 1.3 mm fwhm in air. after travelling 25 km each, the two photons are sent to a 25 km long balanced mach - zehnder interferometer and the necessary indistinguishability is verified by performing a hong - ou - mandel ( hom ) experiment@xcite. besides the hom interference, a conjunction of
we numerically study the case that the quasiperiodically forced hodgkin - huxley ( hh ) neuron is a tonically spiking neural oscillator.   we compare the dynamical responses of this oscillator with those of the periodically forced squid giant axon @xcite, which is subject to periodic synaptic input. in both cases,   a transition from a periodic to a chaotic oscillation was found to occur via period - doubling bifurcations. however, under quasipersideriodic stimulation, a new type of strange nonchaotic ( sn ) oscillating states are found to appear between the regular and chaotic oscillating state as intermediate ones. unlike the case of periodic forcing, these new sn oscillating conditions are characterized by their strange geometry and geometrically strange fractal structure. here  , we consider the conductance - based hh neuron model which serves as a canonical model for tonicallyspiking neurons and show that they exhibit diverse dynamical routes to sn oscillations.
multi - user diversity is a key feature of wireless access networks, where a base station ( bs ) serves a large number of users.   it is often assumed that the bs can select a subset of users with both strong channel norms ( high snr ) and relatively orthogonal directions ( to avoid interference ) to transmit to the base station. in this paper, we show that this is possible, by showing the order - optimality of distributed algorithms for selecting the appropriate group of users to transmit in each slot of a mimo multiple access channel ( mac ) channel with @xmath0 receiving antennas and@xmath1 users. in the first algorithm,   a threshold value for the norm of the channel vector is set, and only users above the threshold transmit. in an iterative process, if the channel state information ( csi ) is shared among the selected users, the same threshold is set for the second algorithm, where _ multiple thresholds _ are set on the norms of the channels of previously selected users. the effectiveness of the distributed algorithm is demonstrated by comparing the performance of the two algorithms under zero - forcing ( zf ) decoding and minimal mean square error ( mmse ) decoding.
we investigate the effect of static charging on suspended ( or free standing ) single layer nanostructures, such as graphene, graphane ( ch ), fluorographene ( fully fluorinated graphene ) ( cf ), boron nitride ( bn ) and molybdenum disulfide ( mos@xmath0 ).   the results are obtained by performing first - principles plane wave calculations carried out within spin - polarized and spin - unpolarized density functional theory ( dft ) using projector - augmented wave potentials. for the exchange correlation potential in layered crystals, van der waals ( vdw ) interaction is also taken into account. under the charged conditions, the bond lengths and hence 2d lattice constants increase as a result of electron removal from the single layer ; consequently, phonons soften and the frequencies of raman active modes are lowered. as a consequence of electron loss,   three - layer, wide band gap bn and mos@Xmath0 sheets are metallized and excess positive charge is accumulated mainly at the outermost atomic layers. owing to coulomb force  , those layers start to repel each other. when exceeded the weak Van der wa
we have performed molecular dynamics simulations on the diffusion of a tagged tracer in a heterogeneous environment.   the results show that the distribution of the displacement of the tagged particle is not always gaussian as suggested by the recent experiments, but is rather diffusive yet non - gaussian. this is due to the nature of the environment around the tagged particle, more often which is viscoelastic, crowded and also to the random or periodic external field which can lead to a deviation from normal brownian diffusion.
recent neutrino oscillation experiments have provided significant amount of evidence which confirms the existence of the non - zero yet tiny neutrinos.   although these experiments have also revealed the origin of mass hierarchies as well as the dirac cp phase, it is still not clear if there exists an alternate experimentally verifiable way to understand some of the yet unresolved issues in neutrini physics. here   we present an analysis of how the expected total flux of neutrines at neutrine telescopes can change significantly by the presence of new physics. among new physics scenarios,   neutrin decay, presence of one light sterile neutrinal and pseudo dirac nature of neut rinos are considered. using the above mentioned scenarios and the best fit values of neutron oscillation parameters (  ), we show that the individual neutrinemic flux can change dramatically from the ones expected from standard oscillation paradigm. for example, the scenario of neutrin decay can change the expected neutrinautrino flux to a great extent, wheareas the changes in the situation of sterile neutrosynthesis and pseudo - dirac neutra are somewhat moderate and should be detectable in
the polarization properties of radio - loud, non - blazar, type-1 active galactic nuclei ( agn ) are not well - studied.   we present the results of linear spectropolarimetry of 8 double - lobed quasars with a total flux of about 1.5  j / cm2 and a broad - line region ( blr ) of about 2.0  km in diameter. for each quasar,   the @xmath4-vector of optical polarization tends to be aligned with the radio source axis on the sky, which is consistent with the unified scheme for the classification of agn as being of type 1 or type 2. by contrast, the polarization of the near - ir continuum in the polarized flux spectrum is weakly correlated with that in the total flux spectrum, and the continuum shape in polarized flux is very different from that in total flux. among these objects, the " 3000  bump ", a pseudo - continuum from and balmer free - bound emission arising within the blr, is observed in the polarization spectrum of the narrow - line regions of the qsos, which are thought to be dominated by small - particle scatterers.
narrow - line seyfert 1 galaxies ( rlnls1s ) are the most powerful relativistic jets in the universe.   they are composed of a large number of black holes and accretion disks, which are formed by the merger of stellar - mass black holes with neutron stars and neutron stars. here   we present an extended summary of our previous work on rlnlns1s, together with new observations from the x - ray satellites swift and xmm - newton, the sloan digital sky survey, and the asiago astrophysical observatory ( italy ). to optimize our efforts, we focussed on a subsample of 76 nls1 s ( 46 radio loud, 30 radio quiet ), mainly characterized by the flat or inverted radio spectral index ( @xmath7,@xmath8 ).. we found some interesting observational characteristics of these sources : about 17% of the sources ( 7/42 ) were detected at mev   gev energies - ray detection of one source of our sample, j@x Math14, thus increasing the detection rate to 19% ( 8/42).in addition to what was available in public archives,
the a7  @xmath0  sc transition pressure of arsenic has been the subject of experimental as well as theoretical dispute.   experimentally, there has been a long - standing question as to whether results obtained by beister  @xcite for this transition pressure are correct over those of kikegawa and iwasaki @xcite. in this work   we undertake indepth studies of the convergence properties of this transition which enable us to proffer reliably converged results. using density functional theory ( dft )  , we find that the lda exchange - correlation functional performs better than two gga functionals with respect to the convergence of the quantities of interest ; however, the differences between the two functionals are not statistically significant.
we investigate the effect of reheating on the gravitational wave spectrum of a global @xmath1 phase transition, and make a prediction for future direct detection experiments.   we find that the frequency of the signal increases with the expansion rate of the universe, and this increase is related to the energy scale of the reheating scalar field. in the case of a non - vanishing inflationary gravitational wave field,   the peak of the re - reheating signal arises at a lower energy scale than that of the inflationary one, which is due to the self - ordering of the goldstone modes from the initial configuration of the scalar fields up to the hubble horizon scale after the phase transition. since the cosmological time scales of the two sources of gravitational waves are nearly scale - invariant, the constraint on the amplitude of the cosmic microwave background from a global phase transition is weaker compared to that of inflation.
the global foreign exchange ( fx ) market is a highly correlated network of interacting exchange rates.   we analyze daily data  @xcite for a 63-element set comprising 60 actual currencies and 3 precious metals : gold, silver, and platinum over a period of 9.5 years from 1 january 1999 to 30 june 2008. using the well - known methods of correlation matrix ( cm ) and minimal spanning trees ( mst ), we find that the currency exchange network is a network of nonlinear interactions between the exchange rates in which one currency serves as a base currency. by applying the triangle rule   @xcites, we show that each currency s exchange rate is strongly correlated with the exchange rate of its base currency ; this is due to the existence of a very small number of exchange rates that can be used as base currencies for all other currencies. since different currencies may have different internal dynamics related to domestic economy, inflation, and sensitivity to events in other countries and markets, the behaviour of their exchange rates is strongly dependent on a particular choice of base currency, there is no absolute correlation structure of the fx network ; its structure depends largely on the base currency.graphical abstract
xmm - newton galactic plane survey ( xgps ) has revealed a large population of x - ray sources. in order to identify the nature of the brightest sources,   an optical campaign has recently been carried out.   one of the newly found cataclysmic variables ( cvs ) in this campaign was identified as Xgps-9 ( = xgp - i j183251 - 100106 ).    we have performed a follow - up investigation of this source by analyzing the data obtained by the epic observation on 8 - 9 october 2009 using the xmm science analysis software ( xmmsas version 11.0.0).the results of this analysis are presented in this paper.
we have recently presented a case - by - case analysis of the positional correlation between unidentified egret sources and supernova remnants ( snrs ).   we find that most of the observed coincidences in positional coincidence with snrs are non - variable, i.e., they are not due to a molecular cloud interaction, but to a physical association. for every known radio pulsar found to be coincident with these 19 egret Sources, we have isolated several interesting candidates for an egret source   snr connection based on the analysis of @xmath0-ray data, the molecular environment of the snr, and any coincident pulsar ( if any ). among them   are g347.3 - 0.5, w66, w28 and ic443, which are the most notable cases for a hadronic origin of the high energy flux detected by egret.
the fission state of ba nuclei is revealed from a microscopic description based on the framework of relativistic mean - field theory.   the most important steps that have been taken here are to find the constituents or the composition of neck, which plays an important role for the explanation of a fission process. in this work, we have used the rmf formalism - a structure calculation method to calculate the constituent(s ) or the particle(s)in the neck region of the fission states of ba nuclear isotopes. as a result, it has been found that the components of neck are mostly composed of the evaporation residues ( er : z@xmath133 ) and fission fragments ( z=2 ). however, the charge distribution for fission fragment with 3@x math11z@x Math1128 is measured using the same approach, but without identifying the constituents ( z or a - value ) of @xmath12. by taking into account the fact that the decay of the excited compound nucleus is due to the emission of the excitation residues and the fissions fragments, we can conclude that the constituents of neck may be divided into two main categories : fission and er.
the nature of dark matter is a fundamental problem in modern physics.   the present day dynamics of the universe is driven essentially by the dark energy ( de ), which is determined by the mass density ratios computed from the wilkinson microwave anisotropy probe ( wmap ) @xcite data. to explain the relative abundance between ordinary and dark matter, we propose a mirror model for the presence of a mirror(s ) sector of particles where the mirror sectors are copies of the standard model ( sm ). using a su(3 ) symmetry, we introduce a new weakly interacting massive gauge boson ( wimg ) which couples the different sectors and, in this way, provides the link between dark and ordinary matter.the model is compatible with the known cosmological constraints, with big bang nucleosynthesis and with the experimental bounds on the cross sections for the interaction with ordinary matter.    the model can be made collisionless if the temperature of the dark sectors is sufficiently lower than that of the visible universe.
in this paper, we briefly review calculation of some big - bang nucleosynthesis ( bbn ) observables by using eft(@xmath0)to find numerical results for some astrophysical observables at thermal energies  @xcite. for these calculations all particles but nucleons are integrated out.   three - nucleon forces are added up to n@x Math1lo for cut - off independent results.
we explore a little - known duality that exists between lorentzian @xmath0 gravity and euclidean gravity with a negative cosmological constant.   we show that the space of histories and the reduced phase spaces of the two systems coincide in the case of a positive cosmology constant ( anti  de sitter space - times ), and that this is due to the existence of a single signature for each point of the ( reduced ) phase space. using some heuristic arguments, we demonstrate this duality by considering the euclidesis of the black hole solution of the btz solution of@xmath4 dimensional gravity with positive mass and no angular momentum.
a general ( multidimensional ) semiclassical description of excitation of a weakly bound rydberg electron by a half - cycle pulse is developed.   the proposed model is nonperturbative and it is applicable to arbitrary spatial and temporal dependences of the exciting electromagnetic field pulses ( hcps ). within this theoretical framework   measurable transition probabilities are represented as coherent sums of probability amplitudes which are associated with corresponding classical trajectories of the excited ryd Bergman electron. on the basis of this theoretical treatment   we demonstrate that angular distributions of ionization probabilities contain a wealth of information about the ionization dynamics of the rydburg electron which can not be obtained from energy - resolved ionization spectra alone. in the sudden - impact approximation  , for example, in which the pulse duration of theexcited hcp is small in comparison with the classical kepler period of the electrons, the energy- and angle - resolved ions are dominated by oscillatory structures and semiclassically catastrophes of the rainbow and glory type. in this paper   these structures can be explained in a clear and intuitive way in terms of interferences between probability amplitude amplitudes of a few classical electronic
condensation of polaritons in semiconductor microcavities,  @xcite, has been shown to be possible by increasing the value of the ( non - resonant ) pump power and by positively detuning the cavity energy above the excitonic energy.   the photoluminescence ( pl ) and resonant rayleigh scattering ( rrsca ) spectra of these systems show that the collective sound mode of the condensate can be observed both above and below the threshold for condensation, where the emission is dominated by the strong condensates at the chemical potential. as a function of the dimensionless momentum @xmath2 and rescaled energy@xmath3, the coherent scattering by disorder of polariton eigenstates into directions other than that of the original probe can be seen in the rs spectra. from our study   we conclude that r, the coherence of the disorder of polarization states into directions different from that of its original probe, represents a powerful tool for investigating the condensed phase.
the @xmath6 violation in charm meson decays is expected to be negligible, due to the presence of new physics.   however, it is critical to first understand the observed branching ratios of all the charmed hadronic decay modes well, within the standard model, before any observation of an anomalous rate or any new cp asymmetry can be claimed to be, as a result of this violation. here   we present a new theoretical approach for the calculation of wilson coefficients of effective operators in the charm sector based on the generalized qcd factorization approach and include important non - factorizable ( nf ) corrections. by using the nf corrections,   the results are in good agreement with the observations and the calculations are consistent with the proposed model independent@xmath13quark diagram or @x Math13topological diagram approach where all two - body non - leptonic weak decays of heavy mesons are expressed in terms of distinct quark diagrams, depending on the topologies of weak interactions, including all strong interaction effects.
bi flux has been used to grow binary iron - based polycrystalline feas crystals in an alumina crucible at 500700 c.   the crystal morphology is needlelike, with typical dimensions of 0.03 x 0.0.03x 0.8 mm@xmath4 and a spin density wave of 5.43747 k. magnetic torque measurements show quantum oscillations in magnetization measurements starting above 10 t. analysis of these oscillations allows for comparison to previous theoretical and experimental results and the establishment of an experimentally verified fermi surface in the sdw state.
the stationary flow of thermionic electrons from the metal surface is currently calculated by the classical richardson - dushman ( rd ) equation.   this model considers the thermal equilibrium between the electron gas and the metal lattice and makes use of the fermi - dirac statistics for the electron energy spectrum in metals at high temperatures, which is based on the implicit assumption of the long time scale relaxation to a thermal equilibrium where the fmdrac statistics describe the electron emission. however, the electron energies of the electron groups in the thermionic electron emission from hot metals differ from those described by the rd equation for long characteristic times when the electron gases and themetal lattice reach the thermal coupling. here  , we present an analytical expression for the temperature dependent thermionic current density using a modified kappa energy distribution for the electrons, which accounts for the contribution of high energy electrons in the emissive behavior of the metal surfaces. as a result, the results of the measurements of the stationary thermionic emission currents from metals are found in good agreement with the theoretical predictions of the modified quantum kappa distribution.
the study of domain - growth is a prototype problem in out - of - equilibrium statistical mechanics.   the results obtained are in agreement with the phenomenological allen - cahn curvature - driven theory @xcite for the time evolution of the mean - size of the ordered domains, i.e., @xmath2, with an exponent@xmath0 at all the temperatures and degrees of asymmetry studied. however, we obtain that the long - time domain- and inter - phase - growth behavior is algebraic, and compatible with the allencahn theory with an exponential growth exponent @x math0 at any temperature and degree of asymmetricity studied. this result is different from the one obtained for the experimentally observed @xcites, which is based on the atomic diffusion of vacancies through the atomic exchange between the two species of the abv lattice model.
the standard model for nova outbursts is a thermonuclear runaway in an accreted hydrogen envelope on the surface of a white dwarf.   the details of the abundance mixing within and at the edge of the convective zone and the fate of temperature fluctuations are therefore crucial elements of the runaway mechanism. in order to capture these effects, several multidimensional simulations of novaOutbursts have been performed. in this study   we show that different, commonly used, mass outflow conditions at the outer boundary can make the difference between a successful runaway model and a model for which the runaway is artificially quenched.
we study the impact of quantum gravity effects on the ground state properties of a fermi gas composed of @xmath15 ultra - relativistic electrons.   we study the effect of heisenberg uncertainty principle ( gup ) on the number density, energy density and pressure of a compact white dwarf in which the mass contribution is mainly from the cold nuclei. for an isolated macroscopic body consisting of non - interacting and ultra-relativistic particles,   the background of the particles motion is assumed to be flat. as a function of the planck energy scale, the maximum observable momentum at low energy   is given as p_i = p_0i ( 1 - p_1 + 2 ^ 2 p_2 ^ 2 ) ,  while the maximum observables at high energy are given as i = i \hbar~\delta_{ij }, $,  such that, where@xmath6 is the momentum at very low energy satisfying eq.   (  ). by using the modified energy - momentum conservation used in @xcite, we find that the bounds predicted from the effective field theory framework @
we present a hybrid method for calculating the strain - strain behavior of dislocation nucleation at the nano - scale using molecular dynamics ( md ) and monte carlo ( mc ) simulations.   the method combines the strengths of md and mc simulations in an easily implementable manner and enables one to reach milliseconds and longer times for several thousands of atoms, with excellent scaling in computational efficiency with system size. by applying the method to the case of au nanowire compression, we show that it is possible to predict the stress - strain rate and activation free energy of the dislocation core at low temperature accurately and reproducibly, with good agreement between the predictions and experimental data.
we present a general formula for the fidelity of a qubit encoded into the same system and subjected to the same transformation as a harmonic oscillator subjected to a gaussian process.   we show how the observed first and second moments of the output states, following from application of coherent input states to the process, yield a convenient parametrization of the process. in this context, we derive the average fidelity over all qubit states encoded in the @xmath4 and@xmath5 fock states and subject to the gaussian processes. using examples from quantum information science, we show that the results obtained can be applied to the evaluation of quantum memories for photonic qubits.
we investigate the ultra - violet behavior of the momentum space propagator of a local quantum field theory using the hypothesis of path - integral duality. in flat space - time,   it has been shown that the modified propagators obtained using the duality principle are lorentz invariant and finite.   we extend this analysis to space - times with constant curvature and explicitly show that the two - point function of the scalar field in these spacetime intervals is finite in the coincident limit.
quantum theory ( qt ) is a formalism with both continuous and discrete elements.   many physicists think that qt implies a discrete substructure for general relativity ( gr ) s continuous spacetime, and the vast majority of the effort in reconciling these pillars lies in " quantizing gravity", as opposed to finding a gr - compatible revision of qt. however, this conclusion is by no means definitive, especially when one considers that one of the biggest unresolved issues of Qt  the " measurement problem "  is directly related to this discrete / continuous division. in this essay  , i argue that the details of this unresolved tension provide us with important clues as to whether nature is fundamentally digital or analog. far from implying that fundamentally nature is somehow  both  ( a meaningless position that many otherwise - rational people have tried to adopt ), qt is more likely describing a parameter regime where one of these descriptions is emerging from the other.
much experimental attention has recently been given to the topic of rabi - oscillations in microwave irradiated josephson systems at very low temperatures @xcite.   the significance of these observations is many fold, and includes a direct connection to a well known quantum mechanical concept in perturbed atomic systems, and a method by which the control of quantum states of a system can be evaluated. here  , we present a new analysis of the slow transient modulations to phase - locking in josephalic systems that are perturbed by microwaves and low temperature thermal fluctuations, and provide specific analytical results for ( rabi ) oscillation frequency and attenuation as a function of the system parameters. using direct perturbations in the dynamical variables, we show that the classical model of microwave - induced multi - peaked switching distributions, used to display quantum mechanical features of joseaphson junctions, has a classical analogue in microwave - perturbed joseophson systems, providing a system response very similar to reported observations under the same conditions. through direct quantitative comparisons with the experimentally reported experiments,   we further demonstrate the validity of the analysis through numerical simulations of a complex system parameterized to mimic reported experiments.
clusters of galaxies are the last and most massive class of bound structures to form out of the big bang ( @xmath0 ).   the baryonic matter within clusters is predominantly hot, diffuse plasma ; the icacluster medium ( icm ) ; the resulting icm flow structures provide vital information about the large scale dynamics of cluster formation, as well as about the physics of the icm plasma@xcite. while thermal x - rays have successfully revealed some icm shocks and other flow features @xcite, distinct x - ray signatures are often subtle and hard to isolate and measure cleanly. here   we present a simple, but coherent formalism that we have found to be useful in predicting behaviors of high resolution 3d mhd simulations of radio - bright, bipolar plasma outflows from active galactic nuclei ( radio agn ) encounters with cluster scale icm dynamical structures, and, in particular, impact on the consequent dynamical form of the agn structures that develop as the Agn plasma penetrates and generates cavities in the icms. using this formalism  , we explore the potential for using such distortions to identify and characterize icm flows, including shocks.
twisted light ( tl ), also called twisted light carrying orbital angular momentum ( oam ), is a highly inhomogeneous light beam that can be used to control quantum states in nanotechnological applications.   the most general form to describe the light - matter interaction is the minimal coupling hamiltonian, where the electromagnetic ( em ) fields enter through their potentials and the dipole - moment approximation ( dma ) is derived under the assumption that the em fields vary little in the region where the matter excitation takes place, and effectively the electric field @xmath0 is treated as spatially homogeneous. here   we review the current state of the art in the study of the interaction between tl and matter using the dma form of the coupling, and discuss the advantages and disadvantages of this form of coupling.
we propose a theory for dissipative singularities in a one - dimensional inextensible continuum, which we conventionally call a _ string_. the chain problems to which this theory is to be applied are presented in section   along with a brief history of the ( supposedly ) paradoxical solutions that have been proposed so far. in due order,   these very problems are then solved within the present theory.   although attained in a different perspective, the conclusions reached here are in tune with those of grewal, johnson, and ruina   ( @xcite ), and of hamm and gminard @xcite before them. there is a common ground between these approaches which perhaps deserves further study and experimental validation.
the polarization of the top quark in the chargino decay channel of the light stop at the lhc is studied.   the energy and angular spectra of the charged lepton in this channel are calculated and compared to those of the charge - neutral top spin @xcite, which decay through the top channel.    the results show that the choice of polarizations used in current searches for the top and chargino channels does not optimize the decay kinematics, but rather leads to the same selection cuts for both channels. furthermore, two simple observables, the opening angle between the charging lepton and the @xmath3 quark and the energy of the #2 quark, are proposed to allow for possible separation of the charginos from the top channels in stop decays.
pulsar radio emission is generally thought to originate within a few percent of the light - cylinder radius ( @xmath5 ) above the polar caps.   many pulsars exhibit a " radius - to - frequency " mapping @xcite which is indicative of polar cap emission. in this letter  , we identify samples of young pulsars and millisecond pulsars ( msps ) that also emit radio and @x Math0-ray pulses respectively. for each sample,   we consider the pulsars in each sample that also emitted radio and/or @x math0-rays as well as the pulse component separations from the main pulse by close to@xmath6 of pulse phase. using a set of pulsars detectable using " blind search " techniques in the relevant band, we show that the radio emission from young pulsers and msps originates at high altitudes in the pulsar magnetosphere, near @xMath5 and from the last open field lines.. these results are consistent with the hypothesis that the wide - beam emission geometries observed in the ~1.5 billion year old pulsar population of the _ fermi _ large area telescope ( lat ) are due to
we have investigated the time - scale of local thermal equilibration of non - strange and strange baryons in an elementary volume in phase - space from the time evolution of longitudinal - to - transverse pressure anisotropy and slope of the energy spectrum of the collision of gold nuclei at four beam energies associated with the future compressed baryonic matter ( cbm ) experiment at fair / gsi laboratory.   we have employed the microscopic, n - body transport model called ultra - relativistic quantum molecular dynamics ( urqmd ) for the study of the dynamic evolution of the matter created in the collisions of gold ions at high baryon density ( @xmath1 times ground state nuclear matter density ) and moderate temperature. using the uv - raman spectroscopy, we have found that the rate of thermalization of the colloidal matter created by the cbm experiment is a function of the incident beam energy of the experiment as well as the initial particle density. on the basis of the results of our analysis,   it can be concluded that the most central collisions of au nuclei are likely to occur at 4.5 gev / nucleon at the highest beam energy associated with
wireless sensor networks ( wsns ) are considered as one of the best sources for monitoring remote fields and critical conditions.   it is also desired to obtain global knowledge continuously i.e., better coverage of area should be obtained. in this paper   we propose a novel strategy named as q - leach for efficient energy utilization in wsn. based upon optimal probability, selection of cluster heads ( chs )   is done in homogenous clustering protocol called low energy adaptive cluster hierarchy ( leach ). through this approach   optimum positions of chs are defined and network is partitioned into sub - sectors which are well distributed within a specific cluster. by assigning ch probability @xmath7 we start clustering process. in every individual round nodes   decides to become ch based upon _ p _ and threshold _ t(n ) given in . in order to acquire better clustering we partition the network into four quadrants. in case of distant nodes,   their exists a hole and gear selects a next - hope node among all neighbors closer to the destination on the basis of minimum cost value. moreover, for closer neighbors from the destination either their exist a closer
we have developed a novel approach to numerical modeling of distributions of test particles in an external gravitational field.   we focus on the conditions favorable to formation of resonant rings near the orbit of just one planet orbiting the parent star and adopt as parameters the mass of the planet, initial orbital characteristics of dust particles, and particle radius coupled with stellar luminosity and mass. using this approach, we have computed about 300 model disks exploring the effects of various resonances given the location of dust sources and adopting as parameters ( mass, particle radius, and luminosity ) the radial distance from the planet to the star and the relative size of the resonant ring. for each model disk, we deal with the positions of ~1000 particles co - rotating with the planet and sort this information into @xmath8 spatial cells ( each cell containing ~11 particles ), thereby forming a 3d grid that models the dust cloud around the star. by combining the results of our simulations with the available observational data on the thermal emission from simulated disks with an embedded planet, we show that the observed observations of highly asymmetric circumstellar disks around the stars @x Math5 eri and vega reveal a remarkable similarity with various types of highly symmetric circumst
the main drawbacks of videos taken by unmanned aerial vehicles ( uavs ) are the undesired shaking motion caused by atmospheric turbulence and jittery flight control of the platform.   the shaky motion in the video proves to mitigate the fundamental aim of using uav for vision - based tasks. while significant work has been done for handheld cameras and ground vehicles, there are limited works for stabilizing videos taken from uav in the literature. here  , we propose a novel method for stabilization of aerial video taken by uav that is similar to the method proposed by nghia ho ( @xcite ).    the proposed method employs finding corners in frames, followed by estimating a 2d motion model between consecutive frames.. then the parameters in motion model are treated as trajectory to be smoothed using an averaging window.,this smoothing of the motion model parameters is different from the motion trajectory smoothing employed by previous algorithms. ’ our framework is also able to process the entire video sequence in real - time, whereas most existing uav video stabilization algorithms perform the processing on - board in offline or post - process way.
the present work investigates how and why the @xmath4 configuration of the nuclear shell model influences the levels in @x Math2c and @x math3c in the frame work of shell model.   the results show that the levels of some excited states are strongly affected by the strength of the@xmath6 interaction, but others are almost independent on that interaction. for the two - nucleon excitation from @x mathematics0 to @x maths1 shell, the levels can be well described by fitting the shell - model hamiltonians based on the observed binding energies and levels.
multithreaded applications are needed to exploit the full processing power of inexpensive multiprocessor machines.   however, developing programs for these machines is not easy as it is harder to get a good view on the state of a parallel program. in this paper  , we present and describe @xcite, a tool that detects data races ( data races are harmful race conditions ) dynamically. during the test phase of, we have found data races in several programs we tested ( including the splash-2 suite  @xmath0, and the athapascan system @xcite ). all of the races that were reported were genuine data races that had stayed undetected until then.database url :   http://www.ncbi.nlm.nih.gov/pubmed/content/5/1471/xmsr_race_detection.shtml
we consider the ordering of quantum states with respect to an arbitrary classical property.   we show that distance measures are, in general, not completely suitable for ordering quantum states unambiguously. starting from the algebraic definition of convex sets  , we introduce and study an order which does not depend on a distinct topological distance.we expand this method to include classical manipulations of the quantum state in an experiment, and classical noise effects.we obtain nonclassicality measures, based on the schmidt number, for both pure and mixed quantum states. using the quantum superposition principle, we quantify the number of non - classical superpositions in the system of the harmonic oscillator.
the theory of synchronization implies that even in uncoupled state the individual elementary units exhibit self - sustained oscillations.   however no less interesting are the systems where local coupling is essential for the very generation of oscillations and not only for their modulation or phase adjustment. here   we study the emergence of collective oscillations in a system of coupled nonoscillatory consumer - resource ( cr ) pairs, which are characterized by the presence of an excitable cytoplasmic bulk and a passive diffusive bulk connected by a transmembrane resistive connection.    we show that the behavior of the two products of the conductive connection can be described by a process called awakening dynamics, in which the concentration of the metabolites in the bulk is equalized by a diffusion process which has a tendency in itself to equalize the concentrations of the excitable bulk. when two such cells are coupled by linear diffusion terms of the form @xmath3, the resulting equations are shown to have a globally stable limit cycle. yet in interaction, a state continues to pulse indefinitely.
the einstein equation can be cast as a hyperbolic system of equations.   this is an important result which establishes lovelock gravity ( gr ) as a legitimate classical theory. however, there is a problem which afflicts the theory : the existence of non - determinism in the hamiltonian formalism. here   we review the problem and discuss the possible solutions to it.
the magnetic behavior of type - ii superconductors depends strongly on the sample shape @xcite.   the magnetic behavior in the perpendicular geometry of thin films with the magnetic field normal to the film plane ( " perpendicular geometry " ) is very different from the parallel geometry, e.g., a more complicated structure of the critical state and the presence of geometrical barriers. here   we present detailed calculations of the distribution of the current density and the magnetic induction distribution across the film thickness in thin films using the two - mode electrodynamics theory. for strong enough bulk pinning,   inhomogeneity of the total current density becomes important, even in the absence of surface pinning ; this is due to the fact that the current is confined to a layer of a depth of the order of the intervortex distance, which is usually much smaller than the london penetration depth and film thickness. as a result of this inhomogeneous current distribution, the magnetic relaxation rate decreases with the increase of the film thickening.
we present a novel algorithm for grover s unstructured search problem @xcite inspired by the quantum approximate optimization algorithm ( qaoa ).   this algorithm is the first to show a quantum advantage for a number of iterations in the intermediate range between @xmath3 and @x math4. using a novel tool, a representation based on spin coherent states, we prove a @x Math5 query complexity for our algorithm.
the collective behavior of groups of interacting dynamical components is essential to understanding and ultimately designing systems.   the ability of a group of coupled oscillators to synchronize despite a distribution in individual frequencies is a broadly applicable phenomenon, ranging from understanding sensory perception to the design of antennas capable of simultaneously sending and receiving signals at the same frequency. in this paper   we study the roles of nonlinear frequency pulling and reactive coupling in the absence of the dissipative coupling in a model of nanoscale mechanical oscillator arrays where the collective behavior is predominantly reactive coupling due to elastic or electrostatic interactions. using the model @xmath0 where the natural frequency of each oscillator is chosen from a distribution representing the amplitude and phase of the mth oscillator, we show that the time evolution of the magnitudes of the amplitudes and phases of the array members is fast compared with that of the phase dispersion, and the only remaining variable for each array member is the phase. when the width of the distribution is narrow, the magnitude of the symphysis is narrow enough to cover the whole distribution, the synchronization is not dependent on the frequency pulling of one oscillator by another, but rather on the reactivity of the oscill
the galactic population  i o  spectral class is of considerable interest and has been the subject of many investigations.   the optical spectra of over 1000 representatives have been observed, and their detailed spectral classification was begun by plaskett & pearce ( 1931 ). here   we present some initial examples of the unexpected developments that such a survey can produce, including the introduction of the new ofc spectral category, which is based on the addition of luminosity classes v  i at subtypes o5o9 and o8o9, and the reclassification of the supergiants into the previously proposed ofc subtype o4. in addition, we present the results of a massive digital survey of all galactic o  stars in both hemispheres accessible to our available equipment, i.e., to about 13th magnitude and 1300 stars from three observatories in spain. for the first installment of the survey, including a new spectral classification atlas, the data will be linked to the public online galactic o - star catalogue ( gosc ; http://dae45.iaa.csic.es/gosmain.html ).
the statistical mechanics of two polymers with constraints on their winding angle has been extensively studied in order to understand the behavior of physical polymer systems, like for instance biological macromolecules of dna or liquid crystals composed of stacks of disk - shaped molecules @xcite.   up to now, however, mainly ideal polymer chains or loops winding around each other have been considered, while the repulsive interactions between the monomers have been treated approximatively or exploited in a clever way scaling arguments integrated by numerical simulations, as for instance in @xcite. here   we present a new approach to estimate the average degree of entanglement of the system, which we wish to estimate by computing the square average winding angle of the two entangled polymers. using quantum mechanical and field theoretical techniques, we are able to obtain exact results even if the repulsion interactions are not switched off.
the detection of gravitational waves ( gws ) will probably mark a new revolution in the history of astronomy.   the detection of gws will directly verify the predictions of the general relativity theory concerning the existence or not of such waves, as well as other theories of gravity. because of the fact the gws are produced by a large variety of astrophysical sources and cosmological phenomena it is quite probable that the universe is pervaded by a background of such wave - like phenomena. here   we present, in particular, a shortcut to the calculation of stochastic background of gw. for this approach   it is not necessary to know in detail the energy flux of the gms produced in a given burst event. if the characteristic values for the dimensionless amplitude and frequency are known and the event rate is given it is possible to calculate the stochastically background of Gws produced by an ensemble of sources of the same kind.
alice is a large ion collider experiment at the Lawrence Livermore National Accelerator Centre ( lhc ).   its main aim is the study of matter under extreme conditions of temperature and pressure, i.e. the quark - gluon plasma, in collisions between heavy nuclei with pp and later p - nucleus beams. as part of the initial physics program  @xcite, alice has been designed to be both general purpose and flexible, allowing additions and modifications along the way as new avenues of investigation open up. here   we describe the development of the alice detector and its various subsystems over the past 20 years, including the experimental design, construction and operation of the first generation of the detector, the @xmath1/@xmath2 system, and the current state - of - the - art particle identification ( pid ) experiments.
the asymmetric simple exclusion process ( asep ) is one of the simple models adequate to describe the transport phenomena.   it is a stochastic system of particles moving asymmetrically on a lattice. in the open boundary system, we can draw a phase diagram by the parameters of inflow rate and outflow rate at the boundaries. on the phase boundary between the low density phase and the high density phase,   there exists a diffusive domain wall ( kink ) which is known as the diffusive domains wall @xcite. here  , we analyse the motion of two kinks in a two - lane totally asymmetricsimple exclusion process based on a decoupling ( mean field approximation ). using monte carlo simulation, we find that the motion from the left to the right of the kink is synchronised though the number of particles in one lane is different from that in another lane. also, we show that the two - point correlation function is small during the relaxation process from the independent motion of both kinks to a synchronised motion of them.
the search for a light higgs boson has been the focus of much attention at the tevatron since the start of run ii.   we use the monte carlo @xcite to predict the inclusive rate of the higgs production process, using an ingelman - schlein type model of diffraction which has proved successful in describing a range of diffractive processes in dis at hera@xcite and also consider two other double diffractive channels : dijet production and di - photon production.    we attribute this difference to rapidity gap survival probability : interactions between spectator partons in the beam protons can destroy a rapidity gaps produced in a diffractive interaction @xcites. 	 we assume that the factor necessary to scale our dijet predictions to data is to a good approximation independent of the hard subprocess, and use it to rescale our higgs and di- photon production cross - section predictions.
the growth of single - wall carbon nanotubes ( swnts ) on a ni(100 ) surface is studied using a tight - binding ( tb ) total energy model.   the model relies on local ( atomic ) energy calculations using the recursion method and is coupled with monte carlo simulations in order to relax the structures. among the different carbon geometries tested  , we find that the most stable one is a hemispherical cap forming a tube embryo. however, the metallic ( nickel ) atoms remain unrelaxed, a strong approximation, considering the order of magnitude of the nic interaction, and no local energy analysis can either be achieved.
the most popular mechanism to generate neutrino masses is the seesaw mechanism.   we have reanalyzed the r  parity violation ( * brpv * ) model, the simplest effective description of r - parity violation in low - energy supersymmetry, and found that it can be broken by non - zero sneutrino vacuum expectation values ( vevs ), i.e., by spontaneously violating r   parity. in the first case, this is due to a bilinear violation of r  parity, where the neutral cp - odd scalar is identified with the majoron, @xmath4, and the lepton number is only one unit of leptons. in another case,   r  Parity violation takes place " a la higgs " which leads to the possibility of invisibly decaying higgs bosons, provided there is an 1 singlet superfield coupling to the electroweak doublet higgses. in both cases   the main mode of undetectable decay is the invisible hjj decay. given the small masses indicated by current data, we propose an alternative inverse seesaw model for the generation of neutrinos from r
the classic model for fueling bright quasars at high redshift assumes that massive black holes ( mbhs ) are powered by major galaxy mergers, which cause large quantities of gas to be funneled into the regions where mbh accretion occurs.   we use cosmological simulations to investigate the role of cold flows in fueling mbh growth in a sample of late - type galaxies at @xmath5 which host moderate - luminosity active galactic nuclei ( agn ). using a combination of time - resolved and multidimensional simulations, we show that accretion of cold gas directly from the intergalactic medium is not the primary driver of mbh growing in these galaxies. instead, we find that cooling of ambient cold gas from cold flows / filaments, minor mergers or secular evolution, and interactions with other galaxies play a significant role in driving mbh grow.
the location of the obscuring torus around active galactic nuclei ( agn ) is a cornerstone of the unification scheme of agn. in the traditional model  , the inclination of the torus to the observer is supposed to be responsible for the major differences between type i and type ii agn ( e.g. *???? ).   the presence of the obscured torus is revealed by the fluorescent fe @xmath0line ( 6.4 kev ), which is characterized by the stability of the emitting region of the fe@x Math0line.    the measurement of the intrinsic width of the x - ray fluorescent lines is limited by the spectral resolution of currently available instruments. in this letter   we compile a sample of compton - thick agn observed with the high energy transmission grating spectrometer ( hetgs ) to measure their intrinsic width from the si @x math0line and estimate the location of its emitting region.
the density matrix renormalization group ( dmrg ) is a method for calculating the ground state properties of quantum impurity models.   it is widely used for calculating expectation values and correlation functions of such chains gaining nearly numerical accuracy. in this article   we present a new extension of the existing correction vector method,@xcite, which allows the calculation of spectral functions for the single impurity anderson model using an effective hamiltonian. by using complete diagonalization of an effective Hamiltonian,   a lorentzian broadened spectral function can be obtained, which is then used to calculate the spectral function for the whole range of impurities in the one - dimensional model. as a result  , we show that the proposed method is a good approximation to the deconvolution of the correction vector spectral function.
x - shaped radio galaxies ( xrgs ) are a peculiar class of radio galaxies with two pairs of misaligned lobes.   the origin of the x - shaped morphology is not yet understood, but several models have been proposed to explain it. in this paper  , we test the viability of the _ backflow model _ with three - dimensional hydrodynamic simulations in elliptical atmospheres using a recently discovered model of the interaction between an active relativistic jet and its host galaxy. by varying the pressure gradient of the surrounding atmosphere,   we show that the wings can be produced by a single agn outburst with powerful jets as the backflow is diverted along the steepest pressure gradient at the minor axis of the host. when these jets are driven in this direction, the wings form as supersonic outflows along the direction of least resistance from a ruptured overpressured cocoon. on the other hand, when the jets are directed in the opposite direction, they either rise buoyantly or are driven toward the center of the cocoon via a mechanism which involves a rapid reorientation of the supermassive black hole ( smbh ) powering the jet. based on these results, we propose that
graphene antidot lattices ( gals ) are promising materials for future nanoelectronics, but the absence of an appropriate band gap, needed in many applications in electronics and optoelectronic applications, limits their usability.   experimental studies have suggested that the localization properties of gals are more likely to be transport gaps rather than band gaps, whereas in some studies the opposite conclusion has been reached @xcite. in this paper   we computationally study the localization property of gal lattices in the presence of disorder using the tight - binding model and the linear - scaling real - space kubo - greenwood ( rskg ) method. by calculating the density of states and the conductivity at different length scales, we are able to give a detailed comparison between the band gap and the transport gap in disordered gals with respect to the size of the localization length and the mobility of charge carrier mobilities.    our simulations show that while the bandgap of an antidot lattice vanishes when the antidot radius is sufficiently small, it also gives rise to a transport gap through anderson localization, which effectively causes a transition from a band insulator into an anderson ins
we present results from the star experiment at the relativistic heavy ion collider  ( rhic ).   we show that the production of vector mesons in ultra - peripheral heavy ion collisions ( upcs ) can be accompanied by mutual coulomb excitation of the beam particles. for the lowest order events with mutual nuclear breakup,   the process is described by three - photon exchange : one photon to produce the vector meson and two photons to excite the two nuclei  @xcite. the rate constants for the formation of these reactions are determined by the cross section of the flux of virtual photons emitted by the target nucleus and the intensity of the photon fluxes. due to the intense photon flux, it is possible for the collision to occur accompanied by coulombs excitations of the beams of ions as well as by the emission of neutrons which can be measured by the zero degree calorimeters  @xcite of the star  setup. using the x - ray diffraction ( xrd ) spectroscopy of the xrd data, we find that the rate constant for the creation of a vector mesone is ~2.5  kcal / mol. when the ions are
radio mini - halos are diffuse extended sources that are found in some relaxed, cool - core clusters.   they have steep radio spectra and sizes of @xmath6  kpc, somewhat smaller than mpc - scale giant radio halos that are present in merging galaxy clusters. here   we report on the results of giant metrewave radio telescope ( gmrt ) radio observations of the phoenix cluster ( ), which were taken as part of a larger radio survey of distant massive galaxy clusters ( i.e., *??????)the emission from mini - Halos typically surrounds the central radio source associated with the brightest cluster galaxy ( bcg ). to explain their presence,   a form of in - situ cosmic ray ( cr ) production or re - acceleration is required. in this letter  , we adopt a@xmath12cdm cosmology with @x Math13  km  s@x math2  mpc@xMath2, @x maths2, #2,#3, #4, #5, #6, #7, #8, #9, #10, #11, #12, #13,
many - body systems that exhibit chaotic properties are sensitive to small perturbations and for that reason extremely difficult to model accurately, since a small addition to the hamiltonian results in a significant change of the energy levels.   chaos allows one to develop statistical theory and calculate matrix elements of different operators between extremely complex many - body states including electromagnetic transition probabilities and probabilities of other processes - see e.g. @xcite. by the presupposition of ergodicity, statistical properties of spectra across the ensemble are transferable to the spectrum of one of the wide range of matrices from the ensemble. here   we show that protactinium has an order of magnitude higher number of principal basis components participating in an eigenfunction of a chaotic system, not unlike that in compound nuclei. using the nearest neighbor spacing ( nns ) distribution as a tool to examine the repulsion of levels, we find that the reorientation of the proton into the center of the spectrum is due to the strong enhancement of the probability density of the eigenvalues of the matrix elements.
clustering of data is a well - known problem of pattern recognition, covered in textbooks such as @xcite.   the problem we are looking at is defining clusters of data solely by the proximity of data points to one another. here   we propose an alternative that is also based on physical intuition, this one being derived from quantum mechanics. given a set of points defined within some region of space, we expect @xmath11 to grow quadratically outside this region, and to exhibit one or several local minima within the region. just as in the harmonic potential of the single point problem  , we expected the ground - state wave - function to concentrate around the minima of the potential @x Math11. therefore we will identify these minima with cluster centers. as an example we display results for the crab data set taken from ripley s book @xcitesite.
the soft photon approximation ( spa ) has been widely used in calculating bremsstrahlung dilepton spectra.   it is based on the early realization @xcite that the cross section for production of low - energy real photons is dominated by the corresponding hadronic amplitude. in practice, this means neglecting the photon momentum in the hadronic matrix element as well as all photon emission from vertices and internal lines. in this paper  , we present an essentially exact formulation for the @xmath10 cross section ( as a function of dilepton invariant mass ) and, in the process, test how far these approximations may be trusted. in order to achieve these goals, we formulate the pion - pion interaction in terms of a relativistic one boson exchange model ( obe ). using the fullobe model, we derive exact formulae for the brems stahlung generation of lepton pairs at very high energies @x Math1.1 mev. with the exception of the case of a fixed meson to baryon ratio,   our results are in good agreement with experimental data.
we present details and spectroscopy for a redshift 4 submillimeter galaxy counterpart of the triple - imaged galaxy smmj16359 + 66130 ( knudsen, kneib & egami, 2006 ).   it is detected at 850@xmath8 m and 450@x Math8 m with fluxes of 11 and 20 mjy, respectively, and its position is ra, dec(j2000 ) = 16:35:55.66,+66:12:59.5 and it has a magnitude of @xmath15.5. in the optical and near - infrared images   there is only one galaxy within a search radius of 8@x math4 from the submm position, which is at very high redshift. to our knowledge, this is the first report of the identification of a redshifted counterpart of this source by combining radio and optical follow - up.
bank default is contagious.   the failure of a single bank can spread through financial networks, generating default cascades. over the past few years, many researchers in various fields of natural and social sciences, such as physicists, ecologists and economists, have been addressing the question of how to prevent financial contagion. however, there is no wide agreement among researchers about how to construct a model of financial contagions. in this letter,   i show the equivalence between an extended version of gai and kapadia s ( 2010 ) model of global contagion and the widely - used threshold model of globally cascades proposed by watts ( 2002 ). basically, financial network models require researchers to construct bank balance sheets. the influence of a bank failure is then examined by sequentially undermining the interbank assets of the lenders. second - round defaults occur if the number of defaulted borrowers among total borrowers exceeds a certain threshold.this mechanism is closely related to that of the watts model of cascades ; however, the essential difference is that i take into account stochastic fluctuations in the value of external assets. for the first round of defaults, the " shadow " threshold of default is appropriately defined in accordance with the volatility of assets
the single parameter scaling ( sps ) hypothesis is the foundation of our understanding of anderson localization in disordered systems.   it implies that the probability distribution of the conductance obeys a single parameter : the ratio of the system size to the localization length @xmath0. here   we perform a careful analysis of the statistical properties of a two - dimensional ( 2d ) anderson model using the sps hypothesis as a test case. for the first time  , we show that the scaling properties of this model are violated at the band center of the model.    the violation is explained by the fact that the mean and variance of the distributions of the components of the scale are not related.
we study the timescale of mass segregation in a two - component star cluster.   the cluster is spherically symmetric in all its properties and completely isotropic in the velocity space, which means that it is regarded as almost collisionless. for the major component, i.e., the less massive stars, we use steady - state probability distribution functions ( pdfs ) of completely collisionless systems to estimate the time scales of mass segregating the more massive objects into the core of the cluster. using these pdfs,   we find that the timescales of mass separation are smaller than those of the pioneering work of spitzer ( 1969 ) and tremaine, ostriker, & spitzer ; however, they are larger than the relaxation timescale found in the original work by spitzer [ j. c. spitzer, p. 531 ; binney & t. tremaine 1987 ; r. b. van der waals, m. lindau, e. k. plummer, and d. vissen, s. alberta, f. h. de novo, et al. :   cosmophotometry of a star cluster of
cable theory is one of the most significant contributions of theoretical neuroscience and has been extremely useful to explain a large range of phenomena.   however, cable theory makes a number of assumptions, one of which is that the extracellular space around neurons can be modeled by a resistance, or in other words, that the medium around neurons is resistive or ohmic. while some measurements seem to confirm this assumption   @xcite, other measurements revealed a marked frequency dependence of the extracorporeal resistivity  @xmath0, which indicates that the media is non - resistive. despite such evidence for non - Resistive media,   the possible impact on cable properties has not been evaluated. in the present paper  , we use numerical simulations to investigate the effect of different types of media on the variation of the membrane potential along the cable, and how such effects could be measured experimentally.
we present a quantum feedback scheme for the on - demand preparation and stabilization of non - classical states of quantum systems.   the system - feedback is based on a strict lyapunov function that ensures better convergence properties by avoiding the passage by high photon numbers during the transient regime. in this paper  , we show that the proposed scheme works even in the presence of delays between the measurement process and the control process. using a predictive quantum filter, we prove that the state - feedback scheme can be applied to generic discrete - time finite - dimensional quantum systems using quantum measurements in order to deterministically prepare and stabilize the system at some pre - specified target state.
the reversible transverse susceptibility ( rts ) technique has been applied to the analysis of the magnetic anisotropy of single - domain magnetic nanoparticles ( nps ) in self - assembled arrays of fe- and fe - based@xcite nps.   the results show that the dependence of the rts on bias field exhibits three distinct singularities, at the anisotropic fields @xmath3 and at the coercive field @Xmath4, under conditions of coherent rotation of the magnetization, which render the method suitable for the extraction of the single - particle anisosmotropy strength. by applying the landau - lifshitz - gilbert ( llg ) equations of motions for dipolar coupled magnetic moments to the description of the thermal relaxation of the moments and orientational randomness of the np moments,   it is shown that the dominant interparticle dipolar interactions are responsible for the large shifts of the coercive peak with temperature.
nonclassical light generation has attracted much attention over the last 40 years, partly because it not only provides a powerful probe for addressing fundamental issues of quantum theory such as complementarity, hidden variables, and other aspects central to the foundations of quantum mechanics ; but also holds promise for many potential applications to quantum information processing, quantum computation and communication, quantum cryptography, quantum imaging, quantum lithography, and quantum metrology. in particular, entangled photon pairs have already been established as a standard research tool in the field of quantum optics.   however, the created paired photons are not maximally time - frequency entangled due to two separate operation processes. here  , we describe the physics behind generation of narrow - band biphotons from the electromagnetically induced transparency ( eit)-based multilevel atomic system. using the heisenberg - langevin method by solving the coupled field operator equations in the Heisenberg picture,   we show that the process of generation of nonclassical correlated photon pairs can be achieved by controlling the eit at a sufficiently high optical depth ( od ) around 50  . the results agree well with the experimental data in the two - photon correlation measurement @xcite.
multiple sclerosis ( ms ) is a neurodegenerative and chronic disease of the central nervous system characterized by damages to the myelin sheaths.   ms patients are typically grouped in three classes according to their disease course : relapsing - remitting ( _ rr_ ), secondary - progressive ( _ sp_ ) and primary - progressive.in this work, we propose a patient reported outcome measures ( _ proms_)-based data analysis pipeline that aims at filling the scientific gap on the prediction of ms disease course over time, focusing on the transition from  rr to   sp_transition. in particular, we take advantage of regularization methods, that is a class of machine learning techniques widely used in the biomedical context as they benefit from good generalization properties as well as they allow to solve both regression and classification problems within the same statistical and computational framework  . the proposed pipeline is tested on a data set collected from ms patients currently enrolled in an ongoing funded project. for the first time,   the pipeline is applied to predict the transition between the rr- and sp_form of ms based on the information extracted from the user - reported self - reported measures @xcite.
the collective transport of coupled nonlinear oscillators in the one - dimensional case is investigated using the frenkel - kontorova ( fk ) model.   the fk model describes a chain of particles with nearest - neighboring harmonic couplings and subject to a periodic potential, where the interaction between the coupling and the substrate potential is reduced to @xmath16 where the coupling strength and the static length of the spring are reduced to@xmath18 and @x Math6, respectively.. the winding number ( or the frustration ) is defined as @x math19, which may strongly affect the spatial configuration of the system.    the kinetic parameters of the coupling are measured by means of the langevin equation and the fokker - planck equation, and the dynamics of the chain is studied by means for the first time using the inverse - friction expansion method. based on the results obtained for the single - particle case,   we show that the competition between the two competing couplings is more complex than previously thought. 	 the main reason for this is the fact that the interfacial temperature of the systems is different from the external driving force, which is usually assumed to be a ga
the origin of dark energy is one of the most challenging puzzles in physics.   the cosmological standard model requires an accelerated expansion of the late universe, driven by dark energy but despite many years of research its origin has not yet been identified. here   we review the current state of the art in the field and discuss the possibility of introducing new degrees of freedom into the equations of gravity to explain the acceleration of the universe.
the langevin equation is one of the most important tools for studying noise phenomena in systems coupled to a fluctuating environment.   it has been shown that the probability density of steady - state lvy flights in external potentials satisfies the fractional fokker - planck ( fp ) equation, which corresponds to the langevinevin equation driven by an arbitrary lvy white noise. here  , we put forward the generalized fp equation and find the analytical solution of this equation for steady - states of lveys with finite variance in a confined geometry. as a consequence,   the proposed solution can be used to study the distribution of flying objects in confined domains.
we have developed a fully evolutionary model of the white dwarf evolution by modules for experiments in stellar astrophysics ( mesa ).   the models were evolved from the main - sequence stars by using the @xmath17 evolutionary code. to do the asteroseismology works on the dav star ec14012 - 1446, we adopted the homogeneous core composition and the total stellar mass of 12 dav stars adopting full carbon core composition. according to the asymptotic theory for@xmath2-mode pulsators, the frequencies of low - degree and high - order @x Math2-modes   are given by @x math9 in eq. ( 1 ), @x maths10 is the buoyancy frequency, @ xmath11 the stellar radius, @Xmath12 the pulsation frequency, and @xMath13 a phase constant. with the evolution method, we tried to evolve the models from pre - main sequence to white dwarf stage. based on the results of the experiment,   all of the three core compositions are rough approximations, rather than results of thermonuclear burning process.
the color - superconducting gap for a two - flavor color superconductor, @xcite, is calculated by solving the gap equation for the quark chemical potential and the four - fermion coupling strength.   the value of @xmath12 depends on the form of the gluon propagator in the cold, dense quark medium, and is related to the critical temperature for the onset of color superconductivity, which is ( to leading order in the strong coupling constant ) related to@xmath2 in the same way as in bcs theory, @x Math5.    the results are compared with those of a recent work on the self - energy of gluons in a two-flavor color super Conductor, where we derive a general expression for the glucose self - energies in the static limit for the unbroken subgroup of the quarks in the color - antitriplet channel, and for the three - flavor subgroup, and compute the corresponding values for the debye and meissner masses of the remaining five glurons.
neutron star, which is called as pulsar in an observational view, is one of the hottest object of study during the past decades, as neutron star provides a gold mine for the fundamental physics, including nuclear physics, astrophysics, particle physics and general relativity.   currently, there are two characteristic parameters of the pulsars ( neutron stars ) have been observed very accurately, that is, the spin frequencies ( or periods ) and the stellar masses. however, up to date all of the observations, including the spin frequency and thestellar masses, still can not confirm or rule out the existence of the low - mass neutron stars in the universe. in this review,   we discuss the constraints on the equation of state ( eos ) of the dense matters based on the accurate and reliable observations on neutron stars, such as the fastest observed spin frequency ( 716hz)@xcite and the observed massive masses ( @xmath6 ), where both of them are come from radio pulsars.
the nature of the singularity in generic cosmologies is unknown although belinskii, khalatnikov, and lifshitz ( bkl ) have conjectured that it is locally mixmaster - like.   while this result remains controversial, it provides a conjecture which can be tested by evolving spatially inhomogeneous collapsing universes numerically. as part of such a study of this issue @xcite, we have considered the gowdy universes on @xmath0 as a test case. here   we use numerical studies to provide support for the extension of the polarized gowdys results to generic gwdy models. from the nonlinear terms in the wave equation for@xmath5, the polarization of the gravitational waves   are shown to act as space and time dependent potentials whose effect is to drive the system to velocity dominance. as the velocity term dominated regime is reached, the potentials approach zero. when the avtd regime reaches zero, the spatial dependence of the wave amplitudes grows at some spatial points and decreases at others, eventually producing small scale spatial dependence in both the waveforms. these non - generic behavior occurs at points where the coefficients of the possible potentials vanish ident
abstractthe cosmic microwave background ( cmb ) exhibits temperature anisotropies on the largest scales.   these fluctuations are caused by gravitational lensing of the cmb by the largest structure in the sky, our own galaxy. here   we present a ray - tracing algorithm to track photon trajectories in a suite of models of the galaxy s mass distribution and show that this distortion mixes the dipole signal with higher - order spherical harmonic modes of the cosmological fluctuations in the plane of the sky. using this method, we show that the magnitude of the distortions is proportional to the distance between the observer and the galactic center, and that the effects of the Galaxy s motion and the Galactic potential are more pronounced than those of the universe s isotropic field of reference. as a result  , we find that the spatial distributions of the observed temperature fluctuations are not homogeneous, but are rather highly heterogeneous. since the galaxy is moving with respect to the Cmb, the doppler shift from the relativistic shift of cmb photons in the galactic rest frame produces a strong dipole feature, which is most prominent in the model with the highest mass, and the lower mass, we propose that
we report the discovery of a close substellar companion to pz tel, a young solar analog ( k0 spectral type ) and a member of the @xmath712 myr  pic  moving group @xcite with a hipparcos distance of 51.5@xmath02.6 pc.   we used angular differential imaging ( adi ) and dual - channel imaging for spectral differential imaging in a fixed cassegrain rotator mode to acquire 45 1-minute frames over 16.7@x Math11 of field rotation in epoch 1 and 23.2@x math11 in epoch 2 of the near - infrared coronagraphic imager ( nici ) planet - finding campaign at the 8.1-m gemini - south telescope @xcitesite. during each epoch, we acquired 45 1 minute frames in a combined adi + spectral differential images of pz  tel b using a flat - topped gaussian profile focal plane mask with hwhm=0.32  ( referred to hereafter as the 0.32mask ). by combining red and blue channel images instead of subtracting the light from the primary star, we increased our sensitivity to detect non - methanated companions by
the standard cosmology assumes that the geometry of the universe can be described by a background metric with small perturbations, where the background is exactly homogeneous and isotropic and is hence of the friedmann - lema^ itre - robertson - walker ( flrw ) form.   this approach is adopted not only for the early universe, for example in describing big bang nucleosynthesis and the dynamics of the cosmic microwave background anisotropies, but is also assumed to be valid at recent epochs. in this paper   we argue that the use of such luminosity distances is indeed justified, provided we are only interested in using such constructions in probing length scales larger than a certain minimum scale which is fixed by requiring that the assumption of homogeneity be valid ( a lower bound on such a scale could be @xmath6 mpc for example ).. more importantly, we propose that the _ dynamics _ of this macroscopic metric must be governed not by the standard einstein equations applied to the flrw metric, but by the effective equations obtained after spatial averaging on constant time slices, as developed by buchert @xcite.
we present a network - based stochastic model of the spread of disease in a highly heterogeneous transmission network.   we show that the probability of invasion from a single infectious individual, and the final size of the outbreak, can be quantified by comparing the results of simulations on this model with those of real statistical data for several other diseases. to capture the probabilistic nature of the real - world process of invasion, and disease transmission in general,   the population can be represented as a contact network, which defines, for each individual, the subset of the population with which it has direct contact. if the population is then assumed to be infinite such that the number of neighbours with which an individual has contact is described by a probability distribution, it is sometimes possible to compute the invasion probability and ( fractional ) final size for the deterministic susceptible - infectious - recovered / removed ( sir ) model by utilising percolation theory. however, for finite populations, there are many numerical methods by which to measure these parameters ; however, endemic behaviour is often associated with non - trivial stationary distributions which for many finite systems do not exist, while the theoretical definition of invasion probability depends on a framework which posits an
the thermal conductance of dielectric beams is a critical parameter that determines the sensitivity, response time, and saturation power of the transition - edge sensor ( tes )  . however, the effect of fabrication processes on the surface physics is less clear and widely treated as a hidden variable in the evaluation of the device performance.   this uncertainty can prolong the design - test cycle, where a parameter such as beam geometry is iterated until the target thermalconductance @xmath3 is obtained. here  , we present a simple analysis of the thermal transport of phonons in a micro - electro - mechanical system ( mems ) designed for cryogenic measurements of the polarization state of the cosmic microwave background at sub - kelvin temperatures. using the fourier law for phonon diffusion, we show that the heat flux entering the beam at one end is reduced to the lowest energy at the exit port, where the diffusive fraction is lower than the ballistic fraction. by applying the theory of isotropic diffusion,   it is shown that the thermodynamic properties of the long beams are sensitive to the surface roughness of the detector membrane.
the mass of the companion star in a low - mass x - ray binary ( lmxb ) of cygnusx-2 has been determined using high - resolution spectroscopy.   the results are consistent with a mass of 1.38 @xmath0 0.07m@xmath1, which is within the range of the most precise mass determinations available from time delays in millisecond radio - pulsars and is also consistent with near - eddington accretion rates of ~1.5 to 2.0 times higher than those observed in high mass binaries.
random matrix theory is of importance for both its conceptual and its predictive powers.   the three fold way classification of hamiltonian hamiltonians for chaotic quantum systems gives rise to ensembles of random unitary matrices, which in turn give rise to the statistical properties of the bulk scaled eigenvalues of the relevant ensemble of hermitian random matrices giving rise to a point process formed from the highly excited energy levels of a chaotic quantum mechanical system. here   we review the recent work on the relationship between the riemann zeta function and quantum chaos, with particular emphasis on the effect of the time reversal operator on the statistical distributions of the ensemble of random hermitia matrices.
we present the results of a numerical study of evolving strings in a minkowski space - time.   we demonstrate the scaling behaviour of two - time correlation functions of tangent and velocity vectors along the string, and show that the largest length scale associated with these correlations, the persistence length and the interstring distance, are both significantly smaller than the causal horizon which suggests that the effects of the expanding background on the correlation functions are small.
thin shell components can be found in many large built - up mechanical structures such as cars, ships, and aeroplanes.   the prediction of the mid- and high - frequency vibrational properties of these structures becomes computationally prohibitive for standard element - based methods, such as the finite element method @xcite. here   we study the case of a singly curved shell, chosen here as an assembly of two plates joined smoothly with a quarter of a cylinder. using a short wavelength asymptotic ray tracing model based on this shell theory  , we derive a wave scattering model for the structure. by comparing the numerical solution to the corresponding ray tracing calculations, we find effective laws for the scattering properties, which may be inserted into ray or wave propagation modelling techniques such as dynamical energy analysis ( dea )@xcite or the wave and infinite element method ( wartime ) @xaite. combining these local scattering models within a larger model of a built -up structure will lead to a hybrid method for structures including curved thin shell components in the mid - frequency regime.
a recent set of papers claim to have detected the velocities of galaxy clusters with respect to the cosmic microwave background ( cmb ) frame by means of the kinetic sunyaev - zeldovich ( ksz ) effect.   we revisit the analysis presented in @xcite, hereafter referred to as k09, which uses the 3-year wmap kp0 galactic mask to isolate the temperature fluctuations at the cluster locations from the cmb dipole. using the filtered cmb maps for 8 differencing assemblies, we construct a cluster sample as similar to that used in k09 as possible and use the best - fit dipole obtained in k9 to measure the signal induced by a bulk flow of all matter out to a redshift of at least @xmath2 (@xmath3 mpc).we find that the uncertainty of this measurement is dominated by primary cmb anisotropy, not detector noise.
bafe@xmaths = 2 spin ladder selenides are two - leg ladder iron oxychalcogenides, which have been recently synthesized and characterized.   the structures of these new materials are discussed in the context of the recent progress in the synthesis of ternary alkali metal iron selenide superconductors, and the new physics of the s = 2 quantum spin systems@xcite.
the existence of two - level tunneling defects as a generic property in amorphous solids was postulated four decades ago@xcite in an attempt to explain the remarkable universality in the low energy characteristics of phonon attenuation at low temperatures.   the mechanism, generic to the disordered state, that leads to the quantitative universality of this property, and its relation to the microscopic structure of the amomorphous state, remain long standing open questions. in this paper   we present numerical results for the density of tunneling states in kbr@xmath8(cn)@x Math9, where the system is modeled by its bare inter - atomic potentials. using a combined monte carlo and molecular statics technique, we relax fragments of kbr : cn in both 2 dimensions ( 2d ) and 3 dimensions ( 3d ) to a low energy state, and then calculate the energy of all states resulting from a tunneling of a single cn defect. remarkably, a sharp decrease of the densities of the tunneling systems is found at energy @xmath2k on both 2d and 3d, but the energy scale of the disorder is much smaller than the
the thermonuclear explosion of a white dwarf ( wd ) star is believed to give rise to a type ia supernova ( sn  ia ).   the process of stellar evolution, its approach to the explosive state, the ignition of the explosion, the explosion stage itself, and the evolution of the remnant are all modelled via a combination of hydrodynamics, turbulence modelling and treatment of nuclear reactions. in this review   we will discuss the role of these methods in the theoretical modeling of the scenario.
the braid index of a link is the minimum number of strands needed in a braid whose closure represents a given link.   it is well known that the span of the jones polynomial of the homfly polynomials of a linked link gives a lower bound on the crossing number of the link, which leads to the proof of the conjecture @xcite. in this paper   the authors seek a special and explicit formulation for certain classes of links ( e.g. the torus links, the 2-bridge links and the fibered alternating links ) where the explicit forms of theHomfly poynomials would allow us to analyze and derive the @xmath1-spans of the Homfly Polynomial of these links. using two explicit formulas, we show that the morton - frank - williams inequality is an immediate consequence of these two homflypolynomial formulas for the hom fly polynoms of the toru links, whereas the mfw inequality is a consequence of the formalism of the cross - over expansion derived by f.  jaeger @xcite in the case of the reduced alternating link diagram.
the study of groups generated by finite automata ( groups of automata or automaton groups ) has received a lot of attention in the last few decades.   this review focuses on the recent developments in the theory of these groups and their relation to other groups, such as iterated monodromy groups, branch structure, and self - similar groups.
generating spatially correlated gaussian random fields with specific statistical properties is an important component and active topic of research in a diverse array of application areas such as ecology, meteorology and geology.   the authors in @xcite have recently introduced a novel approach for generating spatially correlation gaussian free random fields from a matrn distribution.    this approach is based on solving a stochastic partial differential equation ( spde ) with a white noise source function. in this paper  , we introduce three new ideas for generating these samples : ( i ) a mixed discretization of the spde, ( ii ) a hierarchical version of the Spde, and ( iii ) a forward propagation uncertainty quantification ( uq ) using a monte carlo method. to illustrate the advantages of each of these approaches, we present a simulation of subsurface flow in a specified domain, @xmath0, governed by darcy s law, where the hydraulic conductivity represents the permeability of a porous medium. at the end of the simulations,   quantities of interest depending on the velocity and/or pressure, such as the effective permeability, can be computed. since a large number of
the photometric redshift technique is the only practical way to estimate distances to galaxies detected in the great observatories origins deep survey ( goods ).   we have used ground - based optical and near - infrared data from eso facilities, as well as the advanced camera for surveys ( acs ) imaging data from the hubble space telescope ( hst ), to estimate redshifts to galaxies in the goods chandra deep field south ( cdf - s ). using a sample of galaxies with spectroscopic redshifting, we find that the photometric estimates of the distances to these galaxies are accurate enough to estimate the distance to galaxies hosting type ia supernovae, and to convert observable properties to those in the rest - frame. however, the accuracy of the measurements for extremely red objects ( eros ) and active galactic nuclei ( agns ) is lower than that for normal galaxies.
the single - channel kondo ( 1ck ) effect of a quantum dot on the conductance of electrons travelling through it at low energy is well described by a fermi liquid theory, in which the dot acts as a magnetic impurity that interacts with the spins of the electrons in the surrounding leads.   the physics of the 1ck effect can be generalized to more complex models, where a few independent channels compete to screen the impurity. in the 2ck case, when the couplings of the two channels to the impurities are identical, the system flows to a non - fermani liquid fixed point at zero temperature. at this fixed point,   there are no elastic single - particle scattering events off an impurity, and the simple picture of elastic scattering of single particles is no longer valid. in this work, we show that at this frozen fixed point exactly half of the transport through a 2ck impurity is carried by coherent processes. for a single - level quantum dot, the coherent transport is possible if the electron operators in the two leads are decoupled from the dot, and if the effective spin of the electron in the second lead is decoupling from the one in the first lead
the study of dna - interface interactions with surfaces is a subject of general nature.   the notion of adsorption versus depletion, of confinement versus chemisorption and of immobilization versus surface diffusion is addressed in this work using x - ray reflectivity as a means to characterize the process of dnas adsorbed at a liquid / solid interface on a single - crystal silicon substrate material. from an etched si(111 ) wafer, a covalently bonded positively charged molecular monolayer of ethyl undecylenate ( ch@xmath7=ch(ch@x Math7)@x math7)at room temperature   was attached to the surface of the substrate by a chemical process involving hydrolysis of n - hydroxysuccinimide followed by coupling to ethylene - diamine ( nh@x maths7ch@Xmath7ch+@xMath7nh@xcite ), thus obtaining a terminal positively - charged group. under weak yet irreversible adsorptive forces,   these molecules are free to rearrange to their equilibrium configuration ; under strong adsorptions, however, the chains may, nevertheless, maintain some mobility,
interference alignment is a recently introduced interference management technique that is neither resource - reservation - based nor contention - based.   interference alignment is not designed for the many - to - one communication scenario since if all the transmitted signals need to be decoded by a receiver, no two signals may be aligned with respect to that receiver. in this paper  , we present an algorithm that uses a unified view of the signal space to achieve a throughput of @xmath0 in both the many-to-one and many--to-many communication scenarios.. the algorithm is based on the use of a global channel state information ( csi ) which is assumed packet - switched so that we avoid the inefficiencies of resource reservation under low load. using the same csi at each node,   the algorithm asymptotically utilizes the full capacity of the network when the number of users grows infinite, provided that any communication ( desired and undesired ) between the transmitters and the receiver(s ) is synchronized and the signal - to noise ratio ( snr ) is high.
josephson qubits are a leading candidate for scalable quantum information processing in the solid state.   gate and measurement fidelities are within reach of the threshold for fault - tolerant quantum computing based on topological surface codes @xcite, and there is interest in scaling to larger multi - qubit circuits. here  , we propose a scheme for the coherent control of qubit and linear cavity modes using resonant single flux quantum ( sfq ) pulse trains. from a classical model and quantum description of the coupling hamiltonian,   we demonstrate that sf q - based gates are robust against leakage errors and timing jitter of the pulses, with achievable fidelies in excess of 99.9% in gate times around 20 ns. taken together, these proposals point the direction for integration of a multi -Qubit quantum processor with cold sfqs - based classical digital circuitry for both control and measurement.
the description of the movement of a three - phase contact line is an essentially unsolved hydrodynamical problem that continues to attract much interest, for instance, when studying spreading drops, and liquid sheets or ridges moving down an inclined plate.   the understanding of simple contact line movement is also paramount for a deeper insight in related problems such as the dynamical wetting transition and transversal instabilities of moving contact lines. in the present work   we tackle the problem of an asymptotic description of a gradient - driven moving droplet that encompasses both an advancing and a receding contact line by using a chemical potential or disjoining pressure describing a situation of partial wetting on a dry substrate @xcite with a precursor film model where the precursor film thickness is determined through the dis joining pressure.    we distinguish among three regions : the microscopic ( molecular scale ) region : the dominant balance is between disjoining potential and surface tension ; the mesoscopic ( mesoscopic ) region: the predominant balance is viscous dissipation and surface tensile strength ; and the macroscopic ( macroscopy ) region:(1 ) the dominance of the solvent viscosmological equilibrium between the liquid and substrate : the
the process of gravity - driven silo discharge could naively be expected to be a simple one, yet we lack a well defined theoretical framework to explain the experimentally observed grain dynamics in terms of fundamental interactions.   two models were generally considered successful in explaining the global characteristics of the flow ( the velocity profile ) inside the silo, but recent experiments have evidenced some discrepancies concerning these predictions. in this work   we present numerical simulations of a silo drainage process, including the beginning of the operation. using three outlet diameters to study the behavior of the velocity profiles, we demonstrate an evolution between the transitory and stationary states.    results for the probability density functions of the displacements of individual grains reveal non - gaussian statistics and super - diffusive behavior at the beginningof the discharge. in agreement with experiments, non -gaussian to gaussian probability density function s transition is observed in the stationary regime.. finally, we show that the complete sequence of dynamical states displayed by the particles at the start of the discharge can be interpreted in the non - extensive statistical mechanics framework introduced by tsallis @xcite, which can be used to fit the obtained probability density functional functions.
single - transverse spin asymmetries ( ssas ) in high - energy collisions with one transversely polarized hadron are important phenomena that have been observed for more than three decades in various physical processes.   recent experimental measurements of ssas in polarized semi - inclusive lepton - nucleon deep inelastic scattering ( sidis ) and in hadronic collisions @xcite have renewed the theoretical interest in ssas and in understanding their roles in hadron structure and quantum chromodynamics. here  , we present a new approach to study the ssa in dijet production at hadron colliders using the twist-3 efremov - teryaev - qiu - sterman ( etqs ) approach. by considering the spin - dependent cross section, @xmath4, for the process@xmath5 with the jet momenta, we find that the transverse components of the momenta from both sides of the jet are much larger than the sum of the cross sections from the opposite side of the Jet momenta when the hadron s spin vector is flipped, which leads to a nonvanishing ssa. on the basis of these results,   we propose a new definition of the tmd
we investigate the character of ordered orbits in the meridional plane of an axially symmetric galactic model with a disk, a spherical nucleus, and a flat biaxial dark matter halo component.   we use an analytic axisymmetric potential which embraces the general features of a disk galaxy with a bulge to reveal how influential are the main parameters of the system on the level of chaos and on the distribution of regular families of orbits. using the results of @xcite as a starting point, we show that the average angular momentum of the stars in the proposed model is significantly lower than that of the universe as a whole, while the total orbital energy is much higher than the total energy of the entire galactic body. for each orbit in the model,   the angular momentum is found to be inversely proportional to the number of times it is displaced from the center of the galaxy by the mass of the central massive nucleus ( e.g., 0.e., 1.5  kcal / mol ). at the same time, the rate of rotation of the star is very close to the minimum value of the mean angular momentum ( 0.9  kcal/ mol ), suggesting that
while accretion of gas onto compact objects has been studied for over fifty years, much uncertain remains about how angular momentum is transported.   we explore how a stochastically varying effective viscosity leads to the growth of so - called " propagating fluctuations " in our long, global accretion disk simulation and relate the behavior of our simulation to observable properties from accreting black holes.
the reionization of the intergalactic medium ( igm ) is a complex process that takes place in the early universe.   the existence of an early population of pregalactic stellar objects which could have contributed to the reionisation and metal enrichment of the igm has been recently proposed. here  , i review the processes that regulate the formation and the evolution of such galaxies.
we propose a variant of the scotogenic radiative neutrino - mass model by ma  @xcite realized by hypercharge zero triplet scalar field.   the model is based on the electroweak gauge group @xmath2, where the neutrinos are generated by charged exotic particles which are part of the new lepton doublet and the new scalar triplet field. in the next section we introduce the new fields and the radiative mass generation mechanism. in section 3   we impose extra discrete@xmath0 symmetry which enables that the neutrinos masses are induced by the dark matter exchange so that the model can be scotogenized. in sections 4 and 5 we study another scotogensis of the model where discrete @x Math0 symmetry is replaced by @x math1 gauge symmetry. in each section we show the constraints which may be achieved for the model parameters.
quantum information processing seeks to perform tasks which are impossible or not efficient with the use of conventional classical information processing, by using systems described by quantum mechanics. in many quantum input tasks, how quantum information is encoded in the larger hilbert space of composite systems determines the main functionality of the tasks.   entanglement, or a non - local quantum correlation, of an _ individual _ state is an essential resource for performing quantum input task such as quantum teleportation. to analyze properties of spread quantum information described by the set of states, it is necessary to characterize how quantum data is spread by encoding. here, we investigate properties of an extreme case of spreading quantum information that does not consume non -Local resources for decoding but does require non - Local resources for encoding.. we present necessary and sufficient conditions for spreading qu bit information into bipartite states such that qubit information can be extracted by only using classical communications ( locc ) between the two parties. in this task, since we have to investigate simultaneous transformations of _ two _ states @xmath8 under all possible locc, unlike the case of a single known pure bipartites state where lo - popescu theorem @xcite is applicable, the proof
we investigate the effect of impurities on the behavior of a single level attached to the end of a luttinger liquid ( ll ) wire.   we compare thermodynamic properties, in particular the level population, to dynamic properties, such as the level density of states ( ldos ), which can be measured by placing a quantum point contact in the vicinity of the level. using the anderson - yuval approach, we show that while thermodynamic property are universal, and are affected by the various interactions only through a single parameter ( identified as the fermi edge singularity exponent ), dynamic properties are sensitive to the specific physics of the different interaction types.    based on this analysis, we construct different systems, some lls and some not, which are tested numerically to have the same dependence of the population on the level energy, although their ldoss ( of which the population is an integral ) are very different.
complex polynomials and tensors are known to be related.   the hermitian quadratic form of a homogeneous polynomial is a special case of a symmetric complex tensor where the components of the tensor are invariant under the permutation of its indices. in this paper, we study the functions in multivariate complex variables which however always take real values. as is well - known, there does exist a class of special complex functions that always takes real values : the hermeneutic quadrastic form @xmath0 where@xmath1 is a hermitia matrix. here  , we show that such complex functions can be completely characterized by means of eigenvalue decomposition. for both types of complex functions,   two classes of symmetric matrices are identified : those that are bijectively related to symmetric tensors ( i.e., the order of the Tensor is two or more ) and ones that are not ( semi)-symmetrized. among them, the first class is the higher order complex tenser, which generalizes the concept of symmetry of matrices. with respect to the second class,
a flow control scheme that can optimize a utility assigned to a collection of flows as opposed to optimizing the sum of per - flow   utilities can be used to cope with uncooperative flows in data networks.   we design a network control policy consisting of a set of flow controllers at the receivers, a threshold - based packet dropping mechanism at internal nodes, and back - pressure routing at intermediate nodes. using a novel decomposition of the utility functions, we characterize the achievable throughput region in terms of queue overflow rates for an arbitrary arrival rate matrix ( possibly outside the network s stability region ). by combining the receiver - based flow control and packet dropping mechanisms, we show that the proposed policy is nearly utility - optimal ( throughput - optimal as a special case ) and can be implemented only in parts of the network that include the receivers.
adaptive filtering has attracted much research interest in both theoretical and applied issues for a long time due to its good performance, easy implementation, and high robustness.   the least mean square ( lms ) algorithm @xcite has been widely used in various applications such as system identification, channel equalization, and echo cancelation. in recent years, several new algorithms have been proposed based on lms to utilize the feature of sparsity. among them, @xmath0-lms is a family of sparse system identification algorithms that exploit the characteristics of unknown impulse response and exert sparsity constraint on the cost function of gradient descent. here, we analyze the steady - state performance and instantaneous behavior of @x Math0-Lms algorithm using numerical simulations. because most coefficients of a sparse system are zero, the overall identification performance is enhanced by exploiting the sparsity knowledge of the system to be identified. however, it is also found that the performance of the algorithm is highly affected by the predefined parameters.. improper parameter setting could not only make the algorithm less efficient, but also yield steady - states misalignment even larger than the traditional algorithm.,1 the stability condition on step size and steady -State
very low mass eclipsing binary millisecond pulsars occupy a unique niche in pulsar parameter space, between accreting x - ray binaries and isolated neutron stars. in these systems,   mass loss in the secondary is driven either by roche lobe overflow or by winds induced by heating of the secondary by pulsar irradiation.   the resulting mass flow eclipses the pulsar signal at inferior conjunction. at this conference, two observational studies related to eclipse - like properties of very low mass pulsars were given. first, multifrequency observations of orbital and pulse - phase variability of eclipsing twin pulsars b1744@xmath024a and b1957 + 20 were presented.    second, a search for eclipses in very low masses pulsar binaries not previously seen to eclipse was described.. the results of the search are discussed.
the gas content of the protoplanetary disk is crucial for answering fundamental questions in planet formation.   the observational study of the gas in the inner disk is a relatively new area of research, but it is already providing important insights into the structure and dynamics of the disk. here   we review the current state of the art in the field of observational studies of gas in disks. to obtain direct information from the gas content on the time scale in which the planets are expected to form, we use molecular spectroscopy to study the emission of near - ir and mid - ir continuum emission in the ( sub)-mm regions of the inner and outer disks using high - spectral resolution infrared spectrographs. with the advent of space - born infrared spectrophotometry  , we have been able to observe the evolution of the emission features of the gases in the outer and inner disks as well as the dissipation time scales of the emitted gas in both regions.. the results show that the emission characteristics of the emitting gas change as a function of the inclination and size of the region in the disk ; the intensity of the emissions decreases with respect to the inclination of the source and the size of its emitting region.
radio pulsars show a wide variety of modulations of their pulse amplitudes, including bursts and nulls, that affect their detectability in surveys.   this paper describes analysis of a large - scale survey using the arecibo telescope that is sensitive to both periodic and aperiodic signals for pulsars and transient radio transients ( rrats ). during the survey,   a total of 1,898 pulsars were detected by single pulse searches at frequencies of @xmath0.7 to 7  s and pulse widths of 0.0 to 0.5  ms from the known pulsar population. among the most abundant pulsars found were rrat j1819@xmath11458, which has been detected at x - ray energies with properties that are similar to those of x -ray dim isolated neutron stars and high magnetic field radio pulsars, and psr  b1937 + 21, which occasionally emits giant pulses as narrow as 16  ns.    the detection of giant pulses is a potentially powerful method for finding extragalactic pulsars too distant for their normal emission to be detectable by periodicity searches. here   we describe the palfa survey parameters
we propose a new model selection method for locally constant gaussian graphical models based on the concept of local constancy.   our approach is using the idea propounded by meinshausen and bhlmann ( 2006 ) for structure learning in gaussian graphic models, and it incorporates an additional fusion penalty term that aims to enforce the structural constraint of _ localconstancy_. when the nodes of a graph have spatial information attached, then local constration can be interpreted as a certain type of spatial regularity. here   we present theoretical and numerical evidence that our approach outperforms competing model selection algorithms where locality information is ignored.
the subject of superconductivity in multiorbital systems is revisited, in particular to shed light on the possible symmetry of the pairing operator of the pnictides superconductors.   the motivation is that the pairing operators that have been discussed the most thus far assume that onlyaband pairing should occur, namely the two electrons of the cooper pair belong to the same band. however, numerical simulations performed on a two - orbital model@xcite for the p nictides favor an interorbital pairing operator that, when transformed to the band representation, results not only inaband pairing but it includes interband pairing as well. using symmetry arguments and mean - field approximations, the plausibility and physical meaning of such an interband Pairing in multi - ion systems are discussed.
the zitterbewegung ( zb, trembling motion ) of electrons in solids in the presence of an external magnetic field is investigated.   the hamiltonian for electrons in graphene in a magnetic field and its eigenvalues and eigenfunctions are considered. using the landau gauge we calculate carrier velocities and their averages taken over a gaussian wave packet with the use of the dirac equation for free relativistic electrons in a vacuum. by means of the riemann - lebesgues theorem   we show that the trembling motion of electrons does not disappear with time. on the other hand, the zb of electric current and electron position is not damped in time when the system is exposed to an external electromagnetic field. finally, we propose and describe electromagnetic radiation emitted by the trembling electrons.
the geodesics equations of motion of test particles in the background of four dimensional charged black holes in gauged supergravity theories upto four charges are studied.   the main objective of this paper is to study all the possible orbits of test particle in these class of black hole spacetimes by studying the equivalent one dimensional effective potentials of the solutions and present various possible orbits by tuning the mass parameter, multiple charge parameters and gauge coupling constant of the black hole solutions. using the effective potential techniques, the motion of massive neutral as well as massless test particles ( i.e. the timelike geodesic ) in the exterior region of such r - charged blackholes is studied under different values of the parameters involved in the solutions. for the latter, the radial and non - radial geodesies are studied analytically and otherwise numerically. on the other hand, the geodesical equation of motion for massive neutral particles under the same parameters   is studied by considering the two types of spacetime of our interest namely the ungauged and gauged black holes with multiple charges which are identical to the schwarzschild black hole with flat asymptotes in general relativity @xcite
we review the case of bell inequalities for quantum optical fields of varying intensities, especially the cases for strongly driven type - ii parametric down conversion ( with multiple pair emissions ).   we present a kind of mainstream approach to the derivation of such inequalities, which is based on the assumption of device - independent entanglement indicators ( witnesses ) and hidden variable theories. in this way   they can be used to single out non - classical phenomena in the optical domain.
we present a comprehensive analysis of the evolution of excitonic ground state and excited state features in the spectra of good quality 1l to 5l thick flakes of 2 monolayer transition metal dichalcogenides ( tmdcs ) using raman spectroscopy.   we find that the temperature activated energy shifts and linewidth broadenings of the ground state excitons as a function of layer thickness and temperature are consistent with the theoretical predictions, which are found to be opposite to the case of the mono- to few - layer 2@xmath2 monolayers. for the a - exciton transition in our monolayered flakes, we find an unusual reflectance spectral lineshape, which is tentatively attributed to the appearance of a fano - type resonance. on the other hand, for the trion transition, we observe a shift in the emission intensity of the n  =  1 ground state a- and t-excitons from the bulk to the thin layers of the material, which could be attributed to a strong interaction between the excited and the continuum states of the charged exciton.
in recent years, two of us have proposed a new approach to the problem of unification physics, in which it is no longer a matter of reconciling wildly disparate mass scales, but instead an issue of length scales.   the new approach is a superstring - inspired modification of the kaluza - klein idea that the universe may have more spatial dimensions than the three that we observe. since standard model fields do not propagate in the extra dimensions, it is only necessary to evade constraints on higher - dimensional gravity, and not, for example, on high - dimensional electromagnetism. here   we present a detailed analysis of radion stabilization in these new models, and discuss the consequences of this for the evolution of the early universe.
the quantum adiabatic model of quantum computing provides a continuous time model for quantum computing by using the quantum adaption theorem.   it is understood that the speedup in quantum algorithms comes from quantum mechanical features like quantum coherence and quantum correlations like quantum entanglement, that exist amongst the qubits.. however, the innate role of entangement is not clear for general quantum computing tasks. here  , we explore the role of coherence in the deutsch - jozsa algorithm for solving the grover search problem using an analog analogue of the grovver search algorithm. to achieve this, we have quantified the distance between the ground state and the desired state of the hamiltonian with respect to the experimental data and found that the distance from the ground states of the two hamiltonians is proportional to the number of quantum qubits in the system. as a result,   the results show that the mean distance from each quantum qubit to its desired state is 1.5    0.1   on average. when the quantum qu bits are considered in the context of quantum information processing, the difference between the two states is only 0.2
we present new observations of the dynamics of the lobes of two nearby radio galaxies, 3c285 and 3c442a, in which the internal pressures of the radio - emitting plasma are comparable to those of the x - ray - emitting external medium.   we show that these pressures are almost certainly influenced by the properties of the hot gas in the external medium, likely related to galaxy - galaxy interactions and mergers, and discuss the implications of this result for the evolution of the universe as a whole.
we present a numerical treatment of the variational inequality systems associated with european and american call and put options with the black - scholes model.   we use reduced basis ( rb ) methods to provide fast numerical algorithms to accurately solve these systems for a large variety of different parameter values such as, e.g., interest rate, dividend and correlation. in this work  , we present an algorithm to overcome the construction of a suitable low dimensional approximation of the dual cone required for the treatment of additional inequality constraints. by iteratively selecting snapshots maximizing the angle to the current space, we obtain a posteriori error control, which is based on the greedy procedure and tries to capture as much " volume " as possible in the reconstruction of the virtual dual cone. as a second main ingredient for treatment of other inequality constraints, we provide analytical results, in particular a posterioris error control.
the correlation between the cosmological rest  frame spectrum peak energy and the isotropic equivalent radiated energy of gamma  ray bursts ( grbs ) with known redshift is one of the most intriguing and robust correlations in cosmology.   it holds from the brightest grbs to the weakest and softest x  ray flashes ( xrfs ) and is characterized by a scatter in log ( ) of @xmath20.2 dex ( by assuming a gaussian distribution of the deviations ), with the only exception of grb980425 ( which is anyway a peculiar event under several other aspects ). here  , we report the results of a comprehensive analysis of the relationship between the spectra of long grbs with knownRedshift and the spectral peak energy of the corresponding xrf using a new method based on the recently published data from the batse gamma   ray burst detector. for this purpose, we have estimated the upper / lower limits of the correlation for 17 of the 17 events that have been reported so far, and for the other 5 events that are not yet included in the literature. as expected, the results are consistent with the relation = k@xmath0 @x Math
@xcite recently announced that approximately one - third of _ kepler   s planet candidates are associated with targets that have more than one candidate planet.   the fidelity of multiple planet candidates is likely to be higher than that for singles @xcite, and we show herein that the vast majority of these candidates are true multiple planet systems.
deeprotect is a new sensor privacy protection mechanism ( sppm ) that mediates privacy - preserving access to mobile sensor data.   deeprotect enables a new permission model where instead of blocking or allowing sensors, users specify their utility and privacy preferences in terms of inferences that can be derived from mobile sensing data. for instance, users can specify as input a set of useful / authorized inferences denoted by @xmath1 ( e.g., behavior - based authentication, speech - to - text translation ) and a subset of sensitive inferencesDenoted by@xmath2 ( i.e., detection of the text entered in keyboard, speaker identity recognition ) which represent functions that map the mobile sensordata to their corresponding inference results ( i,e. ; labels ), which is the information we want to share ( for useful inferences ) or protect ( for sensitive infusions ).    deeprotector is a web - based app that provides a framework for sharing and protecting user - defined inferences with third - party apps using mobile sensors such as accelerometer, orientation sensor, magnetometer, camera, microphone, gps and so on. here  , we illustrate the
we report here a fully general quantum field theory of the dynamics of strongly interacting photons propagating in a cavityless configuration in a bulk nonlinear optical medium.   the propagation coordinate and time parameter of the propagating photon fluid are exchanged : light propagation in the @xmath1 direction is naturally described in terms of evolution equations while the@xmath2 direction corresponds to a third spatial dimension in addition to the transverse, paraxial, and transverse directions. as usual, the kerr nonlinearity of the medium gives rise to photon - photon interactions, which are mediated by the interaction of the photons constituting the fluid of light with each other via the effects of the optical - axis coordinate and the time parameter. upon quantization to a many - body quantum nonlinear schrdinger formalism, the roles of the propagation coordinates and time parameters are exchanged, and the role of the effective mass to the photons in the #5 plane and chromatic dispersion leads to a  typically different  effective mass in the#2 direction. as a consequence, the experimental observation of strong quantum correlations between the two - photon molecular bound states of a dilute bose - einstein - like condensation in the r
this paper describes a method to generate arbitrarily shaped 2-dimensional arrays of cells by means of evolutionary - developmental techniques, i.e. by evolving genomes that guide the development of the shape starting from a single cell.   the method is called " epigenetic tracking" ( " cell tracking " in previous work @xcite ) and is based on the concept of epigenetic evolution, which involves the evolution of a set of rules in the form of grammatical rewrite systems ; the grammar can be context - free or context - sensitive and can utilise parameters ; variations on this theme include using instruction trees or directed graphs in place of actual grammars. erythrocytes are arranged in a physical space where simulated proteins can be sent as signals from one cell to another, as in nature, where they interact with each other and respond to each other via cellular adhesion and/or genetic regulation. for the purpose of this paper, we have developed a model of development that allows the user to evolve arbitrary shapes in a virtual 3d environment by evolving artificial cells endowed with genetic regulatory networks that allow them to differentiate into different types of cells. here  , we describe the experiments performed and discuss the biological implications of the
the aims of this paper are threefold.   first, we show that the two major methods for the construction of gallager s low - density parity - check ( ldpc ) convolutional codes, due to tanner and jimnez - feltstr " om and zigangirov, are in fact tightly connected. with the help of so - called graph covers,   we establish this connection and show how they can be used to connect the code construction methods. based on these insights, we present a variety of ldpcs constructions and discuss some similarities and differences of these constructions compared to other recent code constructions in the literature. then, we analyze some aspects of the constructed ldpdcs and discuss their possible reasons for the "convolutional gain" before we conclude the paper.
in the last few years, an increasing number of astronomical observations have indicated that current universe is almost flat and undergoing a positively accelerated phase of expansion. to explain this cosmic positive acceleration,   mysterious dark energy has been proposed.   the cosmological constant is the simplest model of dark energy with equation of state @xmath5, but the huge fine - tuning required for its magnitude makes it unfavorable for thecosmologists. in this paper  , we propose a new braneworld model of the universe which uses a four - dimensional ricci scalar in the action on the brane as a quantum correction in the rundall - sundrom ii ( rs ) model. by considering the effect of an induced gravity term as a q - correction in rs model, we have a combined model that called " warped dvali - gabadadze and porrati ( dgp ) branworld " in the literature. here   we discuss the properties of this model and its possible applications in the field of cosmology.
abstracta mid - infrared ( mir ) cometary nebula was serendipitously detected near a pulsar in our survey of young pulsars.   we have made follow - up 24 and 70 @xmath1 m imaging and 7.514.4  @x Math1 m spectroscopic observations with the _ spitzer and magellan telescopes after the initial detection of the nebula at 8.0 @x math1 m. these observations show that the nebular structure is a bow shock, which arises from the interaction between the pulsar wind and the interstellar medium. however, our detailed data analyses raise questions about the association between the nebulae and the pulsum. on the basis of our observational results,   it is not certain that the origin of this nebula is associated with the pulsus.
the symmetry - based approach to the first - passage - time ( fpt ) problem for birth - death ( bd ) processes has been successfully exploited.   it is well known that bd processes are widely considered within applications in ecology, genetics and evolution. due to its relevance in such applications,   the symmetry -based approach has been mainly investigated in the context of the markov property and on certain spatial symmetries of diffusion processes, and on the continuity of their sample paths. here   we give a short review of the main results for symmetric bd process, with attention to fpt problems and related topics. as for one - dimensional processes, the symmetry properties of truncated ones both with reflecting and absorbing endpoints are first discussed. from these cases   some expressions for fpt densities through state 0 and the corresponding avoiding transition probabilities are obtained.    an indication on the extension to the cases of bilateral processes is also provided. 	 various examples are also discussed in detail.
the alpha magnetic spectrometer ( ams )  @xcite is a new particle detector that will be installed on the international space station in 2005.   it will measure cosmic ray fluxes for at least three years, and will be used to search for dark matter signatures and to measure the primary cosmic ray ( cr ) spectra below 1 tev.
in this paper we explore a geometrical modification of the friedman robertson walker ( frw ) paradigm at large scales defined by a modified expansion law for the comoving observers which also depends on their distances.   this approach is suggested by the ` ultra - strong ', or ` extreme'equivalence principle ( eep ). in general relativity ( gr ), spatial homogeneity and isotropy are realized by imposing a group of isometries on the metric tensor, that univocally lead to the frw metric. in this paper   we reconstruct some properties of a frw universe by using looser ingredients than the metric. with respect to the metric,   the cosmological homogeneity is shown to be independent of the time - dependent contributions of local and non - local space - time dependent contributions to the energy momentum expectation value of the test field. as a result  , we show that the concept of cosmologic homogeneity beyond gr can be more general than previously thought.
strange particles have played a major role in high - energy physics since the early 1950s.   it was expected that at high energies the new ( " charm" ) quarks will play a role similar to that of the strange quarks at lower energies as the small mass difference of the up, down, and strange quark populations becomes negligible. in this paper   we present calculations for @xmath12 and@xmath13 ratios from relativistic heavy ion collider ( rhic ) collisions at 200 @x Math3gev center - of - mass energy and at 1.5 eu for the large hadron collid ( lhc ) experiments. using the perturbative quantum chromo - dynamics improved parton model  , we show that the ratio of strange to light quarks is not significantly different at these energies. on the other hand,   the proportion of charm quarks increases with increasing collision energy.
the hubbard model has been used to model the entanglement of two interacting fermions trapped within a chain of square well potentials. in this paper   we compare the results from these simulations to results from the one - dimensional quantum well system, where each well corresponds to one of the hubbard models sites.   when the strength of the interaction, the chain length, and the interwell distance are changed, the results for the electron system are significantly different from those from the Hubbard model.. we also investigate how the interaction strength affects the electronic density, and its effect on the matching between the hub Bard model and the quantum well systems.
we investigate the effects of finite size, definite baryon number and colour neutrality on the emergence of a two - flavour colour superconductor ( 2sc ) at zero temperature.   we use a standard njl model with massless quarks carrying two flavours and three colours and a cubic box with antiperiodic boundary conditions to model the attractive interaction responsible for the pairing of quarks at large densities. in this model,   the quarks are projected onto a colour - singlet state by means of a single - parameter variation of the order parameter @xmath0 from the instanton liquid model. using the same model we find that the superconducting gap persists after projection into a finite state of good quantum numbers.    we also find that it is possible to predict the energy of the second colour - neutral state of the 2sc in terms of the expectation value of the energy in the projected state.
the possibility of a time - varying fine - structure constant @xmath0 has been the subject of a considerable amount of work, both at the theoretical and experimental / observational level.   the best limit from laboratory experiments ( using atomic clocks ) is @xcite, although there are suggestions that due to a number of nuclear physics uncertainties and model dependencies a more realistic bound is@xmath8.    the cosmic microwave background ( cmb ) probes intermediate redshifts, but has the significant advantage that one has ( or will soon have ) highly accurate data. in this article   we review the current state of knowledge on the effects of a variation of @x math0 on the cmb spectra.
the orion complex ( omc-3 ) is a massive cloud core that is undergoing massive star formation at the northern tip of the integral - shaped filament of the orion nebula ( m42 ).   we present 850  imaging polarimetry of this active star - forming region using the new imaging polarimeter at the james clerk maxwell telescope ( jcmt ) on scuba ( submillimeter common user bolometric array ). in this paper  , we describe the polarimeter and the observing and reduction techniques used to measure the polarization of thermal emission from the center of the filament at 850 and 450  using a rotating quartz half - waveplate and a fixed analyzer. for the first time, we show that the magnetic field structure of the region is well aligned with the orientation of the rotating grains in the interstellar medium, which is consistent with the alignment of the grains with their long axes perpendicular to the magnetically aligned source. by contrast, there is no evidence of outflow from either of the two most northern dust condensations in the region, which are known to be in a pre - collapse phase.
we present agn__fitter _ _, a bayesian spectral energy distribution ( sed ) fitting code for active galaxies ( agn ) that allows an integral calculation of the posterior probability distributions of the model parameters taking into account degeneracies and correlations existing among them.   the code constructs spectral energy distributions from existing physical models and calculates physical parameters that are interesting to agn physics, such as relevant integrated luminosities and parameters ruling the physics of the host galaxy. in this way   degeneracies can not only be better visualized but also analyzed and treated. finally, due to the code s bayesian methodology  , the user is able to take advantage of prior constraints on the parameters distributions.
silicene is a monolayer honeycomb structure of silicon and has been predicted to be stable @xcite.   it is expected to be an excellent candidate material for developing fast plasmonic devices because it has a strong spin - orbit - coupling ( soc ) and an electrically tunable band gap. in this work   we combine these two peculiar features and calculate the dynamical polarization function within the random phase approximation ( rpa ) andsilicene s plasmorphed response to optical excitations. using the rpa we investigate how the fields @xmath0 and@xmath1 influence such a response and calculate its decay rate and oscillator strength.. the results show that the polarization function is strongly dependent on the soc and the effect of the exchange field @x Math1.    the decay rate of the plasmons is also affected by the soc induced gap in silicenes and the decay time is faster in the presence of the field m than in the absence of it.
we investigate the thermalization dynamics of an isolated, disordered, interacting many - body quantum system in terms of both local observables and the global return probability.   we define a new quantity, dubbed the " intrinsic decoherence time ", by thresholding the decay of the disorder - averaged return probability after a certain rescaling. using four different models for both spins and interacting fermions, we study the dependence of the rate of the erasure of the initial state information during the time evolution of the isolated system on the disorder strength. across the different models, we consistently find that the intrinsic decosherence time increases monotonically as the disorder strengths increase, and it only displays rather moderate dependence on system size with a reasonable scaling behavior.    we also find that these timescales also exhibit similar monotonic dependence on disorder, giving confidence in the belief that this new quantity is an experimentally accessible physical property characterizing the relaxation dynamics of disordered interacting many-body systems.
extended star clusters ( escs ) in ngc 6822, one of the nearest dwarf galaxies in the local group, are an ideal target for the integrated spectroscopic study of the physical and kinematic properties of outer stellar components.   we present the first result of the integrated spectrum study for four escs among those five discovered in ngcc 6822 based on the observations made with gmos at gemini - south. from the results of the photometric study using the cfht megacam image data, we have shown that the new escs in ngcs 6822 are probably old and metal poor populations. however, the results suffer uncertainties caused by insufficient spatial resolution and shallow photometric depth of the ground - based image data as well as the age - metallicity degeneracy inherent to the photometrically cmd method. in this study, we show that the distance moduli measured by using rr ryrae, cepheid, and nir trgb spectroscopy can be used to determine the physical properties of the outer stellar population in the very outer part of the halo of ngc6822 without any significant uncertainties. according to our results,   the mean
the main objective of the paper is to introduce a family of penalty functions for generalized linear models that can achieve a proper balance between sparsity and stability.   we introduce the family of negative absolute priors ( nap ) and use it to develop what is called likelihood adaptively modified penalties ( lamp ). under suitable regularity conditions,   the lamp results in an asymptotically stable estimator with good sampling properties. by taking into consideration the form of the likelihood in the penalty construction, we show that the lamp family can be used to estimate the likelihood of a given model in a wide range of situations. using the nap family as a framework  , we demonstrate that the most efficient algorithm is the @xmath0 regularization, which is based on the bayesian inference of the prior distributions.
the survival probability of embedded star clusters in milky way is about 4% to 7%.   this is much higher than the number of optical clusters for which the parent molecular clouds have already dissipated and suggests that the clusters are likely to be disrupted before the clouds are dissipated completely. in this work, we study the behaviour of a star cluster in a dispersing molecular cloud in a time varying gravitational field using n - body simulations. by assuming a spherically symmetric external potential, we find that the initial spatial and velocity distributions of the cluster depend on the initial profile of the external potential ( i.e., the initial mass of the cloud ) and the initial distribution of the centre of mass of each cluster.    the initial density of the clusters depends on the size of the outer potential and the ratio of half mass radius to tidal radius. as the internal potentials of the molecular cloud decrease, the local gravity decreases and the cluster becomes more and more compact. at the same time, the binding energy from the cloud decreases and its binding energy to the cluster decreases. when the dissociated cluster is out of equilibrium, the cluster may expand or dissociate completely. erytheoretical observations show
abstractwe analysed the visibility data of the very long baseline array ( vlba ) imaging and polarimetry survey ( vips ) with an automated model - fitting procedure.   we found 60 sources with extended jet structures among 1127 agn observations taken at 5  ghz with the vlbi interferometer in the central area of 128  mas@xmath1128  mas, which is a large sample size and extended field of view compared to the original @xmath01.5 arcsec images. using difmap, we fitted circular gaussians and ellipsoids to the visible visibility data and marked the sources with at least one fitted component farther away than 50  mas from the centre as candidates for having large - scale structure within the full vlbis field of sight. by applying an increased signal - to - noise ratio ( snr ) threshold, we found that in a few cases the distant components are unreliable because of the low flux density of the fitted components. further quantitative classification of the sample is needed ( and planned ).
accretion flows are important ingredients in many astrophysical systems which involve mass transfer from one object to another ( such as in a binary system or set of objects to another ).   the scope of analytical works is usually very limited, since these are devoted to obtain only steady state solutions or to study stability properties of these solutions based on local or in rare cases, global stability analysis. here  , we compare two codes, one is a lagrangian code based on the smoothed particle hydrodynamics ( sph ) and the other is an eulerian codebased on the total variation diminishing scheme ( tvd ) appropriately modified to study cylindrically symmetric problems. both codes are tested against some well known non - linear solutions of axisymmetric transonic accretion disks around a black hole. using the results of these tests,   we show that both of our codes agree very well with the analytical results. armed with the confidence that our codes are reasonably good for studying time dependent flows, we present more complex behavior of time dependent accretion flows in our next papers.
the mechanical properties of biomolecules obtained in atomic force microscopy ( afm ) experiments may be directly connected to corresponding thermodynamical quantities   @xcite with a bit of caution, since mechanical experiments are usually out - of - equilibrium. on the other hand,   they may be of direct importance for what concerns bendability ( dna ), translocation of nucleic acids and proteins across cellular membranes, rigidity and elasticity ( structural proteins ).   the present paper discusses the role of the entropic elasticity of biopolymers in the relationship between the experimental force required to stretch a molecule and its mechanical properties.
disc accreting neutron star systems are amongst some of the brightest x  ray sources in the sky.   they can be split into two broad types namely atolls and z sources, which differ in that they show distinct types of spectral variability and timing behaviour, which link more fundamentally to a difference in the accretion rate and probably also in magnetic field. here   we show that previous difficulties were mainly caused by using poor approximations for the comptonised and reflected emission components. with the use of relativistic smearing of the disc emission as the source of the line broadening, we derive excellent fits to the ginga spectra of cyg x2 at all points on its z track.
the dilepton spectrometer hades is currently being built at the heavy - ion synchrotron sis at gsi darmstadt@xcite.   the first level trigger of the hades detector is derived from the multiplicity of the highly segmented time of flight ( tof ) array. in hadron induced reactions,   this trigger signal is used as a gate for the adcs of the rich detector and as a common stop for the tdcs. here  , we present simulation studies of the Hades first level triggered reaction events in proton induced reactions using a very low multiplicity system p+ni at 2 agev. the results show that the trigger performance of the first stage trigger in the system can be improved by increasing the number of tof paddles carrying coincident signals with respect to the total multiplicity condition imposed on the tof paddle arrays. however, the second level trigger is still more demanding due to the presence of dileptons in the collision.
@xmath0he adsorption on a graphene sheet is an experimentally controllable way of making quasi-2d interacting helium films.   the phase diagram of the adsorbate in the low temperature ( i.e., @xmath4 ) limit has been computed by means of different numerical techniques, and the main findings of our study are largely in line with most previous works on graphene, but with no evidence of any " supersolid " phase, neither in the second nor in the first adsorbed layer.
the lensing galaxy 0957 + 561 was observed with the low resolution imaging spectrograph ( lris ) at the keck ii telescope on mauna kea on march 30 and march 31, 1997.   the time delay for the lensed system has been known for a decade, but the exact value of the velocity dispersion measured by falco et al.  has not been determined. in this study   we reobserve the system using the lris slit rotated by 90 degrees perpendicular to the line connecting g1 and the qso b component, excluding as much qso light as possible, and taking alternate exposures with the slitrotted by @xmath14 and offset to the other side of the x - ray b component. from these observations we find a hubble constant of @x math13.2  from the center of the galaxy g1, which is consistent with the recent observations of falco & colleagues ( 1997, p. falco, j. ; romanowsky, s. ; kundi, c. ; hewitt, t. ; h. ; w. ; shapiro, d. ; n
the fundamental plane ( fp ) of field ellipticals at intermediate redshift @xmath22@xmath23 has been measured using multi - object spectrographs.   the results show that the fp of these galaxies is very thin, i.e., it is only a few orders of magnitude thicker than the local scaling laws described by the fundamental plane in the three - dimensional space defined by effective radius @x Math3, mean surface brightness within the effective radius sb@x math4 and central velocity dispersion @x maths6.    the existence of a tight fp - like relation at substantial look - back times opens up two important questions which bear on the age, formation history, and internal properties of elliptical galaxies : ( i ) how far in the past does this relation apply? and ( ii ) do its parameters evolve significantly with time?
we report the creation of pairs of dark and bright matter - wave solitons in a circular optical - lattice ( ol ) trap configuration in which the soliton is quasi - free in the axial direction.   this setting is more convenient for the experimental study of mobility and collisions of matter - waves than the already realized soliton - supporting settings in the cigar - shaped traps @xcite, as in the circular geometry the motion is not affected by the weak longitudinal trap. in this setting,   both axisymmetric ( azimuthally periodic ) and radial ( axially symmetric ) potentials can be used to create pairs of light and dark soliton pairs. in the case of the radial potential, the dark soliton may run at a constant angular velocity in the trough, while in the latter case it is stable in the central potential well, where it is trapped in a spot - shaped motion. using the quasi-1d trap configuration, we show that the formation of these pairs is possible in the presence of a weakly elongated trap, with an axial parabolic trap in the center of the trap, and a strong radial confinement on the ground state of the corresponding 2
we present a metric for which we analytically solve the geodesic equations and show that a particular set of solutions of these equations represent closed null geodesics ( cngs ).   the spacetime is analyzed in detail to show that it belongs to the class of plane wave spacetimes, which are causally stable and are free from closed timelike curves ( ctcs ) and closed nullGeodesics.
the white dwarf atmopshere is visible in the x - ray source rxj0028.8 + 5917/v709 cas, a variable star with a m@xmath3=14 variable star.   it is the only intermediate polar interplanar star ( ip ) with a significant contribution to the overall flux from the magnetic field of the accretion disk and is seen in the range 3600 - 7200 k. the presence of the white dwarf is consistent with a low magnetic field.
partial - realization theory of linear switched systems is presented.   the main objective of the paper is to demonstrate that it is possible to develop partial - realized theory for hybrid systems. in theorem , we formulate a sufficient condition for existence and minimality of a partial realization. in algorithm ,   a partial - realizing is constructed from the columns of a _ finite _ sub - matrix hankel - matrix, the other one is based on finding a factorization of a   finite   sub - matrices of the hanke - matrix. both the ( partial- ) realization algorithm and the corresponding theoretical results for lsss   follow quite easily from analogous statements for families of rational formal power series.
red blood cells ( rbcs ) have been a model system and an inspiration for the biophysics of the membrane for decades.   many studies have been devoted to adhesion of cells or vesicles and capsules on _ flat and solid _   surfaces @xcite, where, in the case of elastic capsules only, a buckling instability may occur due to the interplay between bending and stretching energy@xcite. however, the influence of intercellular adhesion is less known despite its relevance in dense environments such as blood at physiological hematocrit or even tissues. here   we show that the amplitude of the deformation of contact zones depends non monotonically on macromolecular ( dextran ) concentration and the number and size of aggregates increase with fibrinogen concentration in the physiological range ( from approximately @xmath5 for healthy adults up to @x Math6 in acute inflammatory phases ). by varying the reduced adhesion strength and the reduced volume of the cell  cell contact zone,   the shape of the contact zones can be re - defined and the results are compared with the theoretical predictions.
timing analysis of x - ray binaries and active galactic nuclei ( agn ) using the _ nuclear spectroscopic telescope array _ ( _ nustar_ ; @xcite ) satellite is a powerful tool for studying the inner accretion regions in black hole binaries and agn.   the satellite has been used to measure reverberation lags in both the iron k@xmath3 line and the compton reflection hump together for the first time, and the results are presented here with a new study of the reverberation lag measurements in the agn mcg-5 - 23 - 16 from the same focal plane.
we consider the dark matter - dark energy interaction in the framework of the holographic dark energy ( hde ) model.   we find that the interaction between the two types of matter is proportional to the product of the powers of the number of the density of both, and the interaction rate increases with the amount of the dark energy perturbations in the hde model. by taking the cosmological parameters of the black hole as the reference values, we show that the interactions between the light and dark matter can be considered as natural and physically plausible. for the case of a universe with a future event horizon,   the interaction rates are higher than those of the universe without an event horizon ; however, when the event horizon is chosen as the cut - off scale, the interaction levels are lower than the observed values.    we propose a new form of interaction for the dark space - time - dependent interaction between dark matter and dark energy, which is based on the theory of the quantum zero - point entropy bound of black holes.. the proposed interaction terms are similar to those used in the theoretical model, but they are more appropriate for the cases of interaction - free models.
lanthanum nickelate lanio@xmath1 is a rare example of paramagnetic perovskite oxide characterized by paramagnetic metallic behaviour down to the lowest temperatures and being structurally compatible with many active functional layers.   the main goal of our work is to evaluate single - crystal elastic constants, polycrystalline moduli, and other mechanical properties of this material using first - principles calculations. in order to select the most appropriate density functional theory ( dft)-based approaches for it, at first we focus attention on the geometrical parameters and electronic structure of rhombohedrally distorted phase which is observed in a wide range of temperatures. then, we continue with the elastic parameters and extend our study to the high - temperature cubic phase together with monoclinic structure that is available under tensile or compressive strains induced by various substrates. as a result, the obtained data are compared to the low - temperature experimental data and show that the results are in good agreement with the experimental data.
we develop a globally convergent numerical method for a 1-d inverse medium problem in the frequency domain.   the performance of this method is tested on both computationally simulated and experimental data. to analyze the convergence rate of the quasi - reversibility method, we use a carleman estimate. by using propagation of electromagnetic waves  , we show that the convergence of our method is significantly faster than that of the previous version of the method of @xcite, which was developed for the 3-d case.
the photometric precision of the data from the _ kepler  long cadence ( lc ) mission to find earth - like planets transiting solar - like stars in the solar neighborhood is examined using systematic error - corrected flux time series for the first 33.5 days of data obtained during quarter 1 ( q1 ) of the mission.   these data are available from the pre - search data conditioning ( pdc ) component of the science operations center ( soc ) pipeline, and are processed by first calibrating the raw pixels and then the photometric analysis ( pa ) component subtracts the sky background and extracts simple aperture photometric brightness estimates for each star at 29.4 minute intervals as a function of stellar magnitude. among the 156,097 stars that have been sampled by the spacecraft since may 12, 2009, we find that the photometry of the first month of data from q1 is superior to that of the last three months of q1 with respect to the total number of detected stars and the signal - to - noise ratio ( s / n ) for the detection of @xmath2 for an 84 ppm deep, 6.5-hr transit of a g2v star with a kepler input
the evolution of quasar absorption line ( qal ) systems over the full redshift range from @xmath1 to@xmath2 can be traced by measuring the number of absorption lines due to a particular ion as a function of equivalent width and redshift.   the statistical evolution of these systems is due to some combination of evolution in the metallicities, ionization conditions, and kinematic structuring of the absorbing clouds that produce the absorption lines. with the addition of theoretical modeling of the expected absorption conditions arising from various processes ( eg.  winds, fountains, superbubbles, and infalling material ), the evolution of strengths, overall shapes, and subcomponent structures of the absorption line profiles will allow us to infer a time sequence in the history of the milky way.
backreaction is a method for quantifying the total effect of the transition from smooth universe to fully clustered, vorticity - stabilized structures, in which the apparent acceleration is a natural result of the ever - increasing inhomogeneity of the structure - forming universe.   it is not widely considered to be a viable method for achieving the observed acceleration @xcite, however, because of the neglect of crucial physics via the use of overly trivial backreaction models. here  , i argue that this neglect is due to the simple addition of the newtonian metric perturbation due to a virialized cluster far from a given observation point to the overall ( initially frw ) metric at @xmath3, and that the sum of all such contributions can become dominantly large only by the look - back distance out to which an observer at  can'see'stabilized structures at that given time.
the combination in quadrature of uncertainties due to systematic effects has become quite standard practice in physics.   usually the two kinds of uncertainties are given separately, and the systematic - effect uncertainties are listed individually ( at least for the most relevant ones ) in order to show the potential of further measurements made with the same apparatus. here   we review the issue of uncertainty propagation, starting from general considerations and deducing approximate formulae for practical applications. as a consequence  , we show that the rule of combining inquadrature symmetric uncertainties is a natural consequence of the probabilistic meaning of the statement'the uncertainty associated with the result is that due to random effects '.
we present a new feature - recognition algorithm for coronal - loop identification based on the 2d wavelet - transform modulus maxima ( wtmm ) technique.   we apply this algorithm to an example image from the coronal explorer ( trace ) spacecraft and compare the global statistics against those previously published by arneodo et al. in  and , we describe the advantages and disadvantages of the algorithm and test it on the same sub - image as in. using the same image from trace, we show that the proposed algorithm is able to identify coronal loops in the corona with high accuracy and reproducibility and can be used to study the temporal evolution of hot coronal plasma up to heights of about 50 mm above the surface of the sun.
the ly@xmath0 forest is a well - studied area of the universe that is thought to arise from density variations in a photoionized intergalactic medium that originate in the gravitational evolution of primordial fluctuations.   recently, adelberger et al. ( 2001 ) have carried out the first analysis of this correlation on large scales and at high redshift, using the transmitted flux as the quantity to correlate with the mean number of galaxies in a specified region. in this paper, we present detailed theoretical predictions for statistical functions similar to the one introduced by those authors, namely, the mean values of the mass given an observed value of the transmission flux and the mean value of its distribution for a fixed value of mass, after both quantities have been smoothed over a certain region.we analyze the dependence of these statistical functions on the various parameters affecting the effect of the general cold dark matter model on the observed data, and show that the results are consistent with the observed observations. however, the predictions can still be compared to the galaxy observations to determine the relation between galaxies and mass, which is straightforward if linear bias is a sufficient description of the distribution of galaxies relative to the mass on the large scales being probed.
superwimps, superweakly interacting massive particles produced in the late decays of weakly - interacting massive particle ( wimp ) decays, are promising non - baryonic dark matter candidates for supersymmetric models.   we show that the hadronic branching fractions of the superwimp decays from the first excited graviton in universal extra dimension models ( @xcite ) are significantly larger than those of the lightest supersymmetry particle ( lsp ) and the slepton or sneutrino next - to - lightest suprastructural particle ( nlsp ). these results are compared to constraints on hadronic energy release imposed by big bang nucleosynthesis ( bbn ) constraints on the electromagnetic energy released in the decays after the big bang. at the border between the excluded and allowed regions,   a slight deviation from standard cosmological predictions is expected, providing possible signals in future observations.
the current - induced spin polarization in the topological surface state of three - dimensional ( 3d ) topological insulators ( tis ) @xcite is measured by means of an all - electrical measurement.   the results are compared with those of previous experiments using a ferromagnetic contact as a spin detector, which has been claimed to be due to the spin helicity across the dirac point of the surface state. here  , we directly address this problem and offer a possible solution : the spin polarization can be detected by changing the orientation of the charge - current -induced spin polarization via electrostatic gating. for this purpose, we use the chemical potential of bisbtese@xmath0.0, a 3d ti material with a helical spin texture, as a probe to measure the current - mediated spin polarization. when the sample is backgated from the ferromagnet to the ti surface state,   both types of spin polarization are observed, but the direction of the polarization is opposite to the one that was expected to be caused by the topologically - trivial two - dimensional states with a large rashba spin splitting, which is caused by surface band bending and often coexist
we present a simple model describing an evolution of a quantum state interacting with the environment.   the influence of the environment on the quantum state is represented in terms of a kraus decomposition, where the interaction between the environment and the transmitted quantum state can essentially affect the state and in consequence lower the communication capacity of the information channel. using our model we justify the use of noisy quantum channels for quantum communication.
we review the current state of knowledge about the scaling relations between galaxy properties and their distribution in the @xmath3 universe.   we focus on the size, surface brightness, luminosity and concentration of giant elliptical galaxies, as well as the sic model of the main body of the galaxy, and its relation to dark matter halos, partially - depleted galaxy cores, excess nuclear light and excess light at large radii in the form of halos or envelopes around giant ellipsoids. for those interested in a broader or different overview of elliptical galaxy scaling relations, we also present a brief history of the development of the modern'core - sic'model, which is based on the relationship between the effective radius-(surface brightness ) and the mass - size and mass - density distributions of stars in the galaxy.
electron - cloud effects have been seen with lhc - type beams first in the sps, then in the ps, and finally, since 2010, in the lhC itself.   the electron cloud, at sufficiently high density, can cause both single and coupled - bunch instabilities of the proton beam, give rise to incoherent beam losses or emittance growth, heat the vacuum chamber ( and subsequently provoke a quench in superconducting magnets ), or lead to a vacuum pressure increase by several orders of magnitude due to electron stimulated desorption. for each of these reasons,   beam scrubbing has been proposed as a mitigation strategy against electron cloud. here   we present a new method to determine the actual surface properties of the vacuum chambers related to secondary emission and to the electron -Cloud build up ( @xmath0, @x Math1 and _ r _ = @xcite ), and their evolution in time, based on benchmarking computer simulations of the electron flux on the chamber surface using the ecloud code against pressure measurements for different beam characteristics. this new method allows monitoring the effectiveness of lhcs " scrubbing runs " and provides snapshots of the surface conditions around the lH
the redshift dispersion ( @xmath10 ) is a pair - weighted statistic that probes the pairwise peculiar velocity dispersion in regions of different density and is designed for comparing simulated and observed redshift surveys.   it is based on the cosmic virial theorem ( cvt ), derived in peebles ( 1976a, hereafter p76 ), which links the redshift - space two - point correlation function to the cosmological models of the universe.. the theoretical motivation for our statistic stems from the fact that the cvt can be applied to subsets of particles in a system which correspond to surfaces of constant density.    the main challenges of working with the pair wise velocity dispersive statistics are the strong density dependence of the correlation function and the large variance between estimates of the dispersion measured by each measurement. here   we show that the red Shift dispersion can be calculated as a function of density by averaging over all densities, but only if one retains the freedom to set the normalization of the initial power spectrum normalized to have the same value of@xmath3. using the results of simulations of n - body simulations of four different cosmologic models, we find that
drag reducing flow control is a topic of great interest due to its practical significance for engineering application in different high - speed transport systems such as airplanes, marine vessels or pipelines.   although the tcf configuration has been a longstanding proven tool for the evaluation of control effects on the flow field, the global effect of locally applied control in a developing boundary layer is of major interest for the potential application of flow control in practice. in the present work   we focus on the downstream development of a turbulent wall bounded flow ( tbl ) and the resultant wall friction after control has been applied locally. this is achieved through direct numerical simulations ( dns ) of tbl with sufficiently large streamwise domain length after a controlled region. while the drag reduction achieved in the control region is specific to the applied control strategy, the streamwise development of friction drag far downstream of the control area   can generally be explained by the von krmn integral momentum equation. based on this knowledge we propose a simple model for the drag estimation far upstream of the local control region.
collisional @xmath0-body simulations, in which the equations of motion of @x Math0 particles integrated numerically, have been extensively used in studies of dense star clusters, such as globular cluster, open cluster, and clusters with black holes.   the individual timestep algorithm, first developed by aarseth ( @xcite ), has been a powerful tool that handles the collisional collisions using the hermite scheme. however, the combination of the barnes - hut tree algorithm and the individual Timestep algorithms is not possible on the grape-6 system, because its memory addressing scheme was limited only to sequential access to a full set of particle data, and there is not enough memory size for particle data. here  , we report the implementation of the tree algorithm on grape-9 system that uses fpga(field programmable gate array ) device and the force and predictor pipelines the same as grape-8 chip. from the experimental results,   we show that the performance and accuracy of our implementation are significantly reduced from the direct summation in the original hermite schemes.
@xmath0-parity violation is a well - known consequence of supersymmetry.   the cdf collaboration has recently announced an interesting observation of a resonance in dijets produced in association with a w boson @xcite, which is consistent with a supersymmetric topology in which the lightest ( s)particles in the spectrum are squarks or sleptons and sneutrino. in this paper   we investigate the possibility that this resonance arises from the production and decay of new particles, and explore how this final state can arise in models of supers asymmetry with @x Maths0-Parity violation. for this purpose  , we give a representative model in which only one or two couplings beyond the mssm are needed for this topology to be consistent with the observed cdf observation, and show that the required couplings can have large enough values without causing conflict with any existing constraints. by estimating the size of the necessary @x math1 channel, we show that it is naturally the @x maths1 channel that is the first place for the new physics to be observed in this scenario.
high-@xmath0 cuprate oxides are strongly correlated antiferromagnetic ( af ) mott insulators and it is precisely upon doping with holes that these strongly correlated materials become superconductors.   recent experiments seem to indicate that inhomogeneously textured ( intrinsically nanoscale ) phases characterize the quantum state of high temperature superconditions. in this work   we summarize @xcite and expand on a new scenario for striped superconductor where the interplay between inhomogeneous superfluid density and phase fluctuations determines the critical temperature.
we introduce and analyze a new model of a two - sided market motivated by the net neutrality problem.   the model is the first to assume that the types of both users and internet content providers ( cps ) are power - law distributed, with one parameter ( the exponent ) typically ranging between 2 and 3. using this assumption, we show that the utility of the two populations is modeled in a number of different natural ways. for example, it is assumed that the consumer type is more likely to be a game developer or an application programmer than a user, and that the cp type is less likely to have a large market share than the user.. the model also assumes that the consumers are more likely not to be paid for access to the content they want, but rather to be charged for it. as a result  , the model predicts that the social optimum policy for the internet service provider ( isp ) should be to charge the two sides of the market for access from both sides, and to do so in a socially optimal way.
the aberdeen tunnel experiment in hong kong island is a two - tube vehicle tunnel of 1.9-km long that lies beneath the saddle - shape valley between two hills of over 400 m.   it was constructed in the early 1980s to study the production of spallation neutrons by cosmic - ray muons at a vertical depth of 235 m of rock ( 611 m.w.e. ) using a tracking detector for tagging the incoming muons and a neutron detector filled with a liquid scintillator loaded with gadolinium ( gd ) for detecting the spallated neutrons. in this paper  , we present the design and construction features of the muon tracker and the neutron detector as well as the energy scale calibration of the detector. also, details of the data acquisition and trigger formation of the detectors are presented. finally, detailed details of simulations and detector performance are given.
we present a new analysis of the bragg excitations spectra of strongly interacting one - dimensional ( 1d ) bosonic quantum gases at low temperature using bragg spectroscopy, in which a laser grating of amplitude imprints a perturbation onto the gas at specified momentum and energy.   the results are compared with a recent theoretical analysis of finite - temperature effects in the lieb - liniger model describing repulsively interacting bosons for a 1d bose gas modeled by the hamiltonian @xcite where the atomic mass and the strength of two - body contact repulsive interactions are considered as repulsive quasiparticles and quasihole modes, respectively.the excellent agreement with the solution of the model demonstrates that both fermi liquid - like and quasihole modes with nonlinear dispersion relations are contributing to the experimental correlation signals, in a regime that lies beyond the reach of luttinger liquid theory.
the @xmath0-calculus is a powerful model for representing functions. in its un - typed version, every recursive function can be represented.   but, in this model, a term can be applied to itself and a computation may not terminate. to avoid this problem, types are used. in the simplest case,   they are built from atomic types with the arrow and the typing rules say that a function of type@xmath2 may only be application to an argument of type @x math3. here  , we study other kinds of extension of the simply typed @x Math0-Calculus, i.e. systems where _ equations _ on types are allowed. by making some natural assumptions on the recursive equations, we show that the strong normalization can be preserved. for a set of mutually recursive equations ( e.g., the set of terms of the calculus of constructions ), the most important condition is to accept the equation @xMath17 only when the variable @x maths18 is positive in ##{type }. as a consequence, the system is able to represent all the functions whose totality can be shown in peano first order arithmetic.    we also
microtubules play a central role in eukaryotic cell division.   it is generally believed that microtubules nucleating from each centrosome randomly search the surrounding space for chromosomes by alternately growing and shrinking ( the random search - and - capture model ), and are stabilized upon contact with a kinetochore. however, investigations over the last decade or so have revealed that the chromosomes do not remain passive in this process ; rather, the kinetchores nucleate and stabilize microtubule in their vicinity, a process facilitated by rangtp, which then connects to the astral microtubles emanating from the chromosomes, assisted by motor proteins such as dyenin. in the present paper  , we present a complete theoretical solution to the problem of finding the search time for a fixed target by dynamic microtubular nucleation. our approach permits the calculation of a compact mathematical expression in laplace space for the probability distribution function ( pdf ) of the capture time of a single fixed chromosome by successive microtubocytes nucleated from a single nucleating site ( one at a time ), for arbitrary cell size and kinetic parameters. using this pdf,   we investigate the conditions which optimize the search process
g009.62 + 00.20e is a star - forming complex located at a parallax distance of 5.2  kpc from the sun.   its radio continuum source " e ", named by @xcite, is the most compact component among a number of  regions detected in the field, which align along a ridge of 0.5  pc in size ( e.g., @xmath3  pc ). to explain this intriguing behavior,   it is crucial to image both the maser distribution and the  region morphology with high accuracy. for this purpose  , we have performed astrometric observations toward g009. 62 + 0100.20 of the 6.7  ghz ch@xmath0oh, 1.665 and 1.667 ghz oh, and 22.2-ghz h@x Math1o masers with the australian long baseline array and the very long baseline arrays.    the results show that the presence of an embedded, massive, young stellar object ( yso ) is inferred through interferometric observations of high - excitation ch@Xmath0cn and ch@ xm0oh lines,
the multicomponent scattering approach ( msa)@xcite is presented for the study of synchronic multi - mode transport for massive charge carriers moving through multi - layered structures at coupled and decoupled channel regimes.   the main idea is to search evidences of anomalous events in the conductance and the phase time for an arbitrary number of alternate layers of @xmath4 materials, in the framework of the msa. in sec. the results are presented in terms of the multichannel transfer matrix ( tm ) method based on effective hamiltonians and the monte carlo model of the transmittance of electrons and light holes. by using the tm method, we show that the tunneling time for electron - tunneling through double barrier resonant tunneling ( dbrt ) and the superlattice shows a very good agreement with the previous results for electron- and photon - tunneled through superlattenices @xcite. however, for the hole s transport, it is not so clear how long does it take to a particle to tunnel a single potential barrier from one potential region to the other. moreover, the observed giant conductance phenomena
extensive air showers ( eas ) are known for about 70 years to be cascades initiated by primary cosmic rays in the atmosphere. as such  , they serve as connection to the highest particle energies nature is offering, especially at energies exceeding @xmath0  ev where direct measurements of cosmic rays are hampered by the low primary flux.   the main task of an eas is to reconstruct from the shower observables the parameters of the initial cosmic ray, which is in general straightforward for the particle direction. however, it is more a challenge for the energy and much more for the particles type of the primary. this is due mostly to shower fluctuations, an important eas property given by the stochastic nature of the elementary interaction processes. combined with the steep primary spectrum, the fluctuations impose a particular challenge for interpreting air shower data. here   we illustrate, supported by eas simulations, some characteristics of these shower components and the information they contain about the primary particle.
we have developed a method of calibrating the geometric distortion of images from the hubble space telescope ( hst ) advanced camera for surveys ( acs ) using dithered observations of star clusters.   the method is based on a polynomial transformation of pixel position to sky position and velocity aberration correction of the telescope s rotation and velocity vector. in this paper   we describe our results from a campaign of smov geometric distortion calibration of the stsci space telescope at the 2002 stsci calacs workshop.
the star formation history ( sfh ) of stellar populations ( e.g. galaxies and clusters ) may be derived using the synthetic cmd method ( scm ) based on the interpolation in mass and age of the stellar evolutionary models ( sem ).   we have interpolated in this metallicity range the padova94 models to compensate for the limitation of the grid in meetingallicity, which is too coarse in the z range 0.0004 - 0.004, that is the most commonly used. here  , we discuss our cares and prescriptions to obtain the interpolated tracks for z=0.001.    the comparison between our results and ( *?????* hereafter g00 ) models, of the same met allicity, is shown in order to emphasize the reliability of the interpolations.
we study numerically a two - dimensional foil with an imposed flapping motion, immersed in a stream, that can be released and become free of translational motion.   we used the lattice boltzmann model of  @xcite, with a procedure to include immersed moving boundaries of arbitrary shape subject to hydrodynamic forces. for moderate reynolds numbers, where inertia and viscous forces are important, the results show that the free flapping foil is more viscous than the rigid foil, which is fixed in space.
the @xmath3-wave symmetry of the cuprate superconductors @xcite is investigated using the roth s method and the extended hubbard model.   the results show that the hybridization of the oxygen sites in the system is present in a given amount of doping, which leads to the emergence of the pairing with@xmath14 symmetry in the supramolecular phase. for the doped regime, the presence of the hybridized oxygen sites does not affect the resonance energy of the superconducting phase but it affects the magnetic doping - temperature phase diagram.
we use satellite intensity data from solar minimum to high activity cycle 22 to construct a seismic map of varying solar activity.   we find that the frequency changes of the p - mode oscillation multiplets increase with increasing solar activity, and that the magnitude of these changes depends on the location of the source of the distortion of the sun s magnetic field near the surface. at lower latitudes,   the most significant changes occur in the antisymmetric part of the spectrum of oscillationmultiplets, which is the part that reflects the asphericity of the Sun. at high - latitude, however, there is also large activity in the polar regions, which decreases with the rise of activity at the lower latitude. for the f - modes, where we have the approximate proportionality, a component of @xmath20   is determined, which grows with increasing activity and may be interpreted as evidence for a contraction of the outer layers as activity rises.
in an unpublished paper  @xcite digne and michel prove that the ribbon groupoid of an artin - tits group of spherical type is a garside groupoid.   this result was implicit in @xcite, even though the notion of a gARSIDE groupoid had not been introduced yet. in order to describe normalizers of such subgroups, we introduce a groupoid called the _ ribbon groupoids. here   we extend the notion by proving that in the context of garsidic groups, ribbon groupoidal remain a garsely related groupoid.we prove that for every garsides group with a @xmath2-structure, the positive ribbon category  for every grside group  @x Math1 with a   @x maths2- structure, thepositive ribbon category ( which includes the parabolic subgroups of the standard generating set ) is a torsion groupoid and the ribbongroupoid ( which contains the quasi - centralizer of the free commutative group ) is also a garence groupoid ; however, the ribbon Groupoid is not a garose groupoid
we propose hybrid structures that host a quantum spin hall ( qsh ) state in the absence of a magnetic field.   the heterostructures are constructed by joining a @xmath4 supercell of graphene with@xmath5 supercells of the dichalcogenides. for the structural relaxation we employ density functional theory, including van der waals corrections, to study the following systems : ( a ) graphene on ws@x Math0 or wse@x math0 and ( b ) graphene sandwiched between two ws/wse/xmath0 layers. using the quantum - espresso code @xcite, we show that the intrinsic spin - orbit coupling ( soc ) in graphene can be enhanced such that a reasonable energy gap can be achieved at the k / k@x maths3 points with large band splitting. as a proof of principle,   qsh states are demonstrated for the sandwich systems.
dense molecular gas plays an essential role in the formation and evolution of galaxies.   it could supply the material for starbursts ( hereafter sb ) and for accretion in super massive black holes ( active galactic nuclei, agn ) in galaxies. in return, its properties are strongly affected by these phenomena and their accompanying radiation fields, such as x - ray or uv radiation. here   we present iram 30 m single - dish observation towards ten nearby active galaxies with hcn(j=1 - 0 ), hco@xmath0( j=1-0 ), and c@x Math1h(n=1--0 ) emission lines simultaneously detected in most sources. with the simultaneous detections and measurements of these molecular lines,   our results show that the intensities of hcn, h co@x maths0 and c @xmath1h for various galaxies are significantly higher than those of the general molecular hydrogen gas content of low to medium density ; however, the intensity ratios of these molecules vary with the types of galactic activity.. this may be due to x -ray dominated regions ( xdr ) produced by agn which affects the abundance of hc
we have carried out first principle computer simulations of a microscopic model of parahydrogen ( 2 ) in confinement.   the main physical conclusions expounded here are that nanoscale confinement can greatly enhance the superfluid response of 2, which is suppressed in clusters of greater size, as crystalline order, originating at the center, becomes predominant.
the surface convection of two metal - poor halo stars, hd140283 and hd84937, has been simulated using a compressible radiative - hydrodynamical code.   the simulations are performed on an eulerian mesh with 100x100x82 zones, covering 35x35x12 mm ( hd 140283 ) and 21x21x8 mm(hd8 4937 ), respectively. in the present   letter we briefly present results for two of the stars and compare emergent spectra from the 3d models with those of conventional 1d models.
holonomic gates are quantum logic gates that are intrinsically robust against unwanted perturbations.   they are based on the theory of holonomy and of the associated holonomy groups in principal fiber bundles, a subject which is familiar to theoretical physicists due to the central role played in gauge theories and in the well - known phenomenon of abelian adiabatic phases. here   we present a new approach to the implementation of such gates by means of an ideal unitary transformation in the encoding eigenspace of a quantum hamiltonian depending on the external parameters of its eigenprojectors ; this transformation is considered as a geometric phase ( geometric phase ) with a simple geometric interpretation as a holonomy phenomenon. for the first time, we show that the behavior of the proposed holonomic gate can be applied to the classical model of quantum decoherence, and we find that it is possible to realize such gates with high intrinsic robustness against classical noise.
the search for neutrinos coming from dark matter ( dm ) annihilations or decays in galactic halo has been performed by icecube @xcite.   the data obtained from icecube 22-string configuration set the 90% c.l. upper limit on dm annihilation cross section @xmath4@x Math5s@xmath6 for @x math7 channel at @x maths8 tev   @xcites.    the preliminary result of icecube 40-string galactic - center analysis improves the above limit to @xMath9@x mathematician5s=@x mathematic6   . based upon these upper limits,   a comparable constraint on the cross section of @Xmath7 annihilations, which could take place in the core of earth, is derived  @xcitic for tev range dark - matter masses.  also, upper limits on the annihilation cross sections of @x mathematical10 and @x mathematics11 channels are also obtained.
clouds affect the incoming solar irradiance, and it is one of the important factors in the intermittency and variability of obtained solar radiation.   we investigate the impact of cloud coverage on the variation of received solar radiation obtained on the earth s surface using ground - based sky cameras and human observations. for this purpose, we use a clear - sky model to estimate the total cloud cover obtained from human observations, and then calculate the cloud radiative effect ( cre ) values from the measured- and clear -sky solar radiation values. by analyzing the correlation between the cloud coverage and the corresponding cre value, we find that the overall cloud coverage is significantly correlated with the variation in the solar radiation observed from the satellite images. however, when the clouds are occluded, the sun will not receive the same amount of solar radiation as when the skies are completely clear.
lipids self - assemble into a variety of different structures as a function of concentration and temperature.   most prominent is the lamellar phase, which consists of a stack of lipid bilayers separated by layers of water. in the case of lipids with large spontaneous curvature,   the monolayers tend to curve towards the water regions and form inverse cylindrical micelles. here   we discuss the existence of yet another structural type, which often occurs between the lameelar and the inverse hexagonal phases : the inverse bicontinuous cubic phases ( ibcps ). like the lamelar phase  , the ibcp is formed by non - bilayer lipids and their stability can be controlled by changing the lipids spontaneous curvatures. for example, if temperature is increased, the size of the head groups hydration shell decreases, spontaneously curvature increases and the lipid monolaying tendency tends to curve away from the water region, whereas at ambient temperatures, it transforms into a two - dimensional array of inverse cylindle micells. since the structure of the interpenetrating labyrinths of cubic symmetry is similar to that of the inversehexagonal phase, the latter
the thermalization of two cold gases confined in a box or a harmonic trap is studied by means of the boltzmann - nordheim equation for each phase - space distribution function.   the results show that the confinement plays a crucial role in the rethermalization of both species, and that the temperature of the trapped gas can be used as a parameter to estimate the time it takes to return to equilibrium.
the magnon dispersion of magnetic excitations in ca@xmath0ruo@x Math1 ( cro ) is studied using inelastic neutron scattering ( ins ) with and without polarization analysis on crystals containing 0, 1, and 10  % ti combined with density functional theory ( dft ) calculations.   the results show that the main in - plane transverse magnon modes exhibit a large anisotropy gap, underlining the impact of broken tetragonal symmetry in combination with spin - orbit coupling ( soc ), and oxygen moments that lead to an additional branch of the dispersion observed in the neutron scattering experiments.
the mass and decay constant of the ground state strange tensor meson @xmath0 with quantum numbers @x Math1 from the vacuum is calculated by means of the qcd sum rules.   the results are compared with experimental data on the same meson and the order of the su(3 ) flavor symmetry breaking effects is also estimated.
we present a theoretical study concerning the fate of the metal - rich ( planetary ) material which may fall onto solar - type stars during their early lives, and we analyze the consequences of such events on the abundances of light elements.   we compare our results with the presently available observations, and give some predictions and discussion for future work.
the functional relevance of communities in protein interaction networks has been the subject of considerable recent attention.   many algorithms have been proposed that locate dense regions in a network, often called communities, and then assess their functional homogeneity by searching for terms in a structured vocabulary that are significantly over - represented within such communities. here   we use a single high - throughput experiment on the growth rates of gene knock - out strains of the yeast yeast saccharomyces cerevisiae to investigate the biological relevance of these communities at multiple resolutions ( scales ) within the yeast protein interaction network. using the whole proteome as a model system, we find that the number of interacting proteins in a community is not a sufficiently stringent test of functional relevance when the group of proteins in question is a community because two proteins that interact are functionally more similar than a randomly chosen pair of proteins. instead  , we use all the annotations available within a given ontology to assess the function of a community, and compare the results with those of other communities found in the same network at different levels of resolution. from this analysis,   it is shown that the most biologically relevant communities are found at high resolution, whereas the least relevant communities occur at low resolution
the full automorphism group is one of the fundamental objectives when dealing with symmetry properties of mathematical objects, such as vertex - transitive graphs.   it is often the case, however, that certain additional symmetries, though hidden or difficult to grasp, are present. in this paper  , we propose a method for studying the existence of automorphisms that act as odd permutations on the vertex set of a graph. using the orbital ( di)graphs of transitive groups, we show that every vertex -transitive graph of order twice a prime admits an odd automorphistic group, and hence every transitive group of degree twice a Prime is orbital - odd. by taking advantage of the fact that the above actions of the two basic orbital graphs of the petersen graph and its complement are the only simply primitive groups of degree Twice a Prime  a direct consequence of the classification of finite simple groups ( cfsg ), we prove that these groups are orbital -odd.
star cluster - related astrophysics has made significant progress in the past decades, yet we still have a long way to go before all of the key questions in contemporary star cluster physics are fully understood.   this is particularly true for the process of star cluster formation, which is one of the most important physical processes underlying most of modern astrophysics. during the 2010 ria workshop on stellar clusters and associations,   i was asked to chair an open discussion on outstanding questions in current research in this area.    the lively exchange of new ( and some old ) ideas that ensued led, i believe, to a general broadening of participants perspectives  in the true sense of the traditional tertulia.
the einstein - vlasov system with bianchi symmetry is a system of integro - differential equations on a lorentzian manifold.   it has been studied by the theory of dynamical systems and for almost all lie groups the @xmath6-limit set is known as @xcite. in this paper   we show that the late - time behavior of the system is well approximated by the e Einstein - dust system, i.e. the system where the structure constants of the lie algebra associated to the lie group vanish.
we study the collective motion of a trapped macroscopic ensemble of ultracold gas coupled to the intensity of the light field inside a cavity which serve as a mechanical oscillator ( analogous to a movable mirror ).   we show how the optical force modifies the frequency and damping constant of the collective density excitations of the bose - einstein condensate(bec ) of two - level atoms in the @xmath3 state with mass@xmath4 and frequency@x Math5 of the @Xmath6 transition of the #xmath7 line of @x math2, strongly interacting with a quantized single standing wave cavity mode of frequency @x maths8. by using a resonant optical cavity around a kerr type medium, the quantum fluctuations of an incoming light beam can be reduced below the standard quantum - noise limit for a given quadrature component. this system may serve as an optomechanical control of quantum fluctuations using a bose einsteincondensate.
physical aging is the spontaneous temporal evolution of out - of - equilibrium systems.   nonexponential relaxation is ubiquitous in complex systems and is frequently described by the stretched exponential or the kohlrausch - williams - watts ( kww ) decay function @xcite, where the characteristic lifetime @xmath1 corresponds to the specific lifetime for a given number of page views and the stretched exponent@xmath3 reflects the nonexponentiality. here  , we propose a useful methodology for evaluating the non - exponentiality in article page views by adopting a modified stretched exponential function @xfite. using reliable statistical data of article page view normalized by the number of initially maximized page views, we show that when an article receives attention, its daily page views reach a peak and then decay with time, which is similar to a physical relaxation process.
the renormalization group invariants ( rgis ) of the minimal supersymmetric extension of the standard model  ( mssm ) are used to determine the current probability distribution of the soft supersymmetry - breaking parameters at the tev scale.   the results are compared with experimental constraints imposed by the lhc. in this article  , we use the pmssm rgi probability distributions to analyze three particular issues :   the possible scale of gaugino mass unification ;   messenger scale parameters in a realization of general gauge mediation ; and   message scale parameters associated with minimal gauge mediation.  also, we study the consistency of the scale of this gauge gauge mass unification with experimental limits.
solitons are localized waves propagating within a background medium, and are characterized by a dip of the density and a phase slip.   they have recently become a topic of intense research in weakly - interacting atomic bose - einstein condensates ( @xcite ), being routinely generated in a number of experiments, both in a controlled manner and as a result of dynamical processes. here   we show that soliton - sound interactions play a key role in the dynamics of two or more solitons in an inhomogeneous atomic condensate, and identify optimal realistic experimental conditions for observing such an effect. using mean field theory, we analyse the motion of soliton oscillations within either a single harmonically - confined condenate or different spatially - separated sub - regions of a condensated and conclude that, within mean field theoretical, dark soliters can interact via the emission / absorption of sound waves over a long range, without ever approaching very close to each other.
active cytoskeletal material is a key component of the actomyosin cortex in cells.   it is thought that the activity of the cell cytoskeleton plays a major role in the control of cell motility and morphology. in this paper   we model the behaviour of active droplets immersed in a passive fluid using linear perturbation theory. by making justified assumptions, we are able to predict non - equilibrium phase transitions in both of the systems we consider, and predict how the droplet deformation couples to these.see research article http://www.biomedcentral.com/1471-2148/7/9/8.
the slow manifold is a low - dimensional, attracting invariant manifold which governs the long term dynamics of dissipative evolutionary equations.   we seek to obtain an approximation to such a manifold that is ( a ) simple to obtain during numerical computations, and ( b ) only requires evaluations of time derivatives of the state, such as would be available from a legacy code. in our work  , we show that this can be achieved by approximating the system with a finite - dimensional approximation to the slow manifold using a subset of the basis for the full set of variables in the original problem. when the system is described by a microscopic simulation, the partial differential equation is transformed to a lower - order differential equation so that the slow manifolds can be parameterized by the slow variables, @xmath13, and the solution of y = f(y, z_0(y ) + o ( ) = y / dt = f ^n+m ^n + dz/dt = z = g(y,z)/, where y is the singularly perturbed form of the evolution equation. within the reduced system,   points on each of the solutions must be uniquely determined by @x
nonlinear behavior of a material can be either desirable or unwanted depending on the operating properties of the fabricated device.   the emergence of nonlinearities in the optical response of a hybrid material may be undesirable in other devices, e.g. raman scattering process in fiber - optic cables and decreases the quality factor of microwave cavities. in this paper, we show that it is possible to manage the nonlinear behavior using path interference effects. as an example, we place a quantum oscillator ( qd, molecule or a nitrogen vacancy center ) at the hot - spot of a metal nanoparticle ( mnp ) dimer which has localized surface plasmon - polariton ( pp ) resonances @xmath4 and@xmath5 for the polarization field. without the presence of the quenching rate of one of the oscillators, the second harmonic generation ( shg ) process occurs when the two excitation paths for the absorption / polarization of the incident light are unresolvable. even in the resonance condition for shg conversion ( that is, /2h, +1h+2h+3h+4h+5h+6h+7
we investigate the effects of coherent inflaton oscillations on the temperature anisotropies in the cosmic microwave background ( cmb ) by using the maxwell - weyl approach to gravitational waves.   we find that coherent oscillations of the inflaton condensate drive parametric resonant amplification of scalar fluctuations on very large scales, and that this effect is particularly strong for the transverse traceless modes of the cosmotic tensor perturbations, which are given by the divergence - free electric and magnetic parts of the weyl tensor.    we also find that the magnitude of the effect depends on the initial conditions and the coupling strengths of the preheating model.
galaxies are one of the fundamental building blocks of classical astronomy.   they contain the vast majority of stars in the universe and their large - scale distribution in space, as observed by redshift surveys, serves to constrain key cosmological parameters. however, their formation  and even to some extent their constituents  are still only poorly understood. here   we review the current state of knowledge about the structure of galaxy halos in a dark - matter dominated cosmology, with a focus on the role of the gas physics.
the momentum distribution of nucleons in a nucleus is a property which is experimentally accessible and reflects the effects of short - range correlations in the independent particle model ( ipm ).   the momentum distribution is obtained by integrating the nucleon - hole spectral function over energies from the fermi energy to the ground - state energy of the nucleus with nucleons. here   we investigate the influence of these correlations on the spectral function for finite nuclei without employing the local density approximation. using a realistic meson - exchange potential, we find that the spectra of the quasihole wave functions at all energies are affected by the presence of short- and long - range correlation functions. when the nn interactions are not present in the ipm the contributions of the spectral functions are reduced to a small fraction of those of the non - correlated basis function method ( cbf ) while the contribution of the hartree - fock approximation is unaffected.    the results are compared with experimental results for the same nucleus and show that the observed momentum distribution can be used to derive the full energy dependence of the nuclear wave function for very light nuclei.
super - eddington accreting massive black holes ( seambhs ) are thought to be the central engines of many type - i active galactic nuclei ( agns ).   they show a unique dependence of their bolometric luminosity on the supermassive black hole mass ( @xmath10 ) which, given a proper calibration, can be used to infer cosmological distances. in this paper  , we use reverberation mapping ( rm ) of dust and gas near the central supermassive Black Hole ( bh ) to investigate the relationship between the bh mass and the size of the active galactic nucleus ( agn ) by measuring the resonant echo from the central bh at redshifts up to about ~7.5. using this method, we find that the mean diameter of the main bh is significantly larger than that of the rest frame for most agns with a range of sizes ranging from 0.1 to 1.0  km.    the size distributions of the two main bhs show a strong correlation with each other and with the number of agns in the region of interest ( r2 = 0.976, p < 0.05 ). when
we present details of a recently developed nonlinear chebyshev - filtered subspace iteration ( chefsi ) method for solving the self - consistent - field ( scf ) equation in density functional theory ( dft ) calculations.   the method is based on a sequential nonlinear Chebyshevs - filter - based iterative framework, and it is implemented in our own dft package called parsec ( pseudopotential algorithm for real - space electronic calculations ) @xcite. within chefsi,   explicit eigenvectors are computed only at the first iteration, and the problem is solved by a single subspace filtering step to provide a suitable initial subspace. after the first step, the explicit computation of eigvectors at each scf iteration is replaced by a one - step subSpace filtering step.    the method reaches self - consistency within a number of scf iterations that is close to that of eigenvector - based approaches.. however, since eigenvertevers are not explicitly computed after this step, a significant gain in execution time results when compared with methods based on explicit diagonalization.
soft gamma - ray repeaters ( sgrs ) are unusual objects, even for the rarefied field of compact object astrophysics, with only 4 definitely identified over the last 30 years.   we report here x - ray observations of sgr 1806 - 20 with the _ chandra x - rays observatory ( @xcite ), as well as near - infrared observations of the field with the cerro tololo inter - american Observatory ( ctio ) 4-meter telescope and the hartung - boothroyd observatory 0.65-m telescope. using _   chandra _ to localize sgr 19 to an accuracy @xmath0, we then identify possible infrared ( ir ) counterparts to sgr1806 -20. based on these results, we propose that sgr19 may be a member of a cluster of embedded, hot, luminous stars in the field of the radio nebula g10.0 - 0.3, which contains the most luminous blue variable star in the galaxy ( the lbv star ), at least one wolf - rayet star of type wcl, and at least two blue hypergiants of luminosity class
conformally invariant field theories are very important class of models.   some of them are rather artificial, and are more interesting from the mathematical point of view. in all physical field theories the kinematic terms in the lagrangian are always conformally invariants. here   we provide a simple methodology on how to generate such field theory lagrangians which shall be guaranteed to be conformally symmetric with appropriately chosen group action of the conformal transformations on the fields. this principle can be in particular useful when searching for theories where the spacetime metric tensor field is not a fundamental quantity, but a derived one.
the @xmath8 meson decay is one of the most interesting processes in the heavy quark physics.   it is the lowest bound state of two heavy quarks with open ( explicit ) flavors and it lies below the@xmath13-threshold, so its decays via strong and electromagnetic interactions are forbidden. here   we present a new model - dependent wave - function which is based on the effective lagrangian of the okubo - zweig - iizuka ( ozi ) rule@xcite for the b - quark decay, which is also forbidden by the ozi rule. to obtain the best possible results, we have used experimental data obtained from the tevatron run ii@xaite@xfite and the future cern large hadron collider(lhc ) experiments at the cern lhc as well as the nrqm(non - relativistic quark model ) approximation of the perturbative qcd ( pqcd ) which is used to calculate the part which can be calculated in the framework of the non - perturbation qcd using the wave - functions. in order to reduce the theoretical uncertainties of the
the magnetic fields of neutron stars ( nss ) decay significantly over their life times and thus cause the observed age mismatch, i.e., the spin - down ages of the supernova remnants physically associated with them, which are normally significantly larger than the spins of the nss.   pulsars are generally very stable natural clocks with observed steady pulses ; however significant timing irregularities exist for most pulsars studied so far. in this work   we investigate the long term timing irregularities of these pulsars by measuring the time of arrival of pulses at the spin rate of a pulsar with @xmath3 years and the spin period of its spin down or characteristics ages,@xmath5 ( @x Math6 is the initial spin periods of the given pulsar ), and the recovery from previous glitch events, @x math9 years, using data from the pulsar - to - star ratio ( rt ) database.    the results show that the timing irregularities are dominated by the recoveries from previous glitches and/time noise, and that the values of @x maths0 for the majority of the pulsars measured are not caused by magnetic dipole radiation or by any other systematic loss of rotational energy,
the cooperative behavior of random noise and deterministic periodic signal in a nonlinear system is investigated in this paper.   the first passage time density function ( fptdf ) at resonance is studied in terms of two universal functions, which clearly isolate its dependence on the length of the medium. to investigate the effect of synchronization between noise and periodic signal as we change the frequency it is shown that a single dominant peak of fpt df at resonance occurs when the synchronization is at its maximum with respect to the forcing frequency for which the variance of the first order moment ( mfpt ) of the Fptdf is at the same frequency as the cycle variable of the periodic signal. also, a scaling relation is obtained between fpt Djs at resonance for different lengths so that one could map fptdcs at arbitrary length on a single fptdc at our choice by such scaling relation.
the advection of a scalar observable by a velocity field is described in classical hydrodynamics by the linear scaling analysis of (  ).   the structure functions of the scalar field display a power law behaviour in the inertial range with anomalous scaling exponents. to investigate how the introduction of a time correlation in a gaussian velocity field affects the statistical properties of the scalp observable, we introduce a time correlated velocity field in a shell model which provides exponentially decaying time correlations. by means of stochastic variational calculus, we show how to rewrite the equations of motion for the Scalar correlations in integral non closed form. using the ornstein - uhlenbeck process, we analyse the model both analytically and numerically.
weyl semimetals, which are three dimensional ( 3d ) analogs of graphene, have attracted considerable attention because they are expected to give a broad spectrum of unusual physical properties as two dimensional graphene.   the goal of this paper is to investigate electronic collective modes of charge oscillations in chiral gapless electron - hole systems in 3d and to find wave - vector - dependent plasmon dispersions, considering interband transitions along with chirality of the systems. for chiral systems with the isotropic linear and quadratic band dispersion, we find that the long - wavelength plasmons lie outside the landau damping regions due to the depolarization effects arising from the interband transition and therefore they do not decay by producing electron -hole pairs. for the systems with an anisotropic non - linear energy dispersion at low energies, the density dependence of the plasma frequency along the direction of non -linear dispersion behaves like that of the isotropy - dependent linear band model, while along the directions of linear dispersion it behaves like those of the gradient - dependent non - exponential model. for multi - weyl systems with both linear and higher - order distributions,
the crossover from the bardeen - cooper - schrieffer ( bcs ) superfluid phase of loosely bound pairs of fermions to the bose - einstein condensate ( bec ) regime of tightly bound composite bosons is studied in the quasi-2d fermi gas of alkali - metal atoms.   the crossover is achieved by performing the regularization of the zero - point energy which appears in the gaussian fluctuations of the mean - field equations at zero and finite temperature, which is due to both fermionic single - particle excitations and bosonic collective excitations. as a function of the bosonic gas parameter, the two - dimensional ( 2d ) state of the system is characterized by quasi - condensation and algebraic long - range order, which are driven by strongly enhanced quantum and thermal fluctuations. for the first time,   these results are in excellent agreement with the experimental data of the crossover experiment.
the anomalous hall effect observed on ferromagnetic crystals has been known for more than a century.   the theory of this phenomenon has a long and confusing history, with different approaches giving in some cases conflicting results. here   we present theoretical treatment filling this gap. in contrast to standard transport theories the hall conductivity is expressed in terms of local atomic - like orbitals which are further expressed via the berry phase curvature. using a two - band model in tight - binding approach   it is shown that for perfect bloch electron systems this description coincides with that given by the so - called orbital polarization moment @xcite indicating intrinsic, topological, origin of anomalous Hall effect. however, up to now, generalization of this theory to systems with strong disorder or subject to other types of fluctuations seemed to fail. within a mean field approach,   electron properties are controlled by a single electron hamiltonian which we consider in the following standard form @xmath7 \, + \,\nonumber \, \mu_b \, { \vec{b}_{\rm eff } } = \frac{1}{\rm _ eff } + \begin{document}{
the recent observations of a significant gev emission from the external shock synchrotron in grb 941017 @xcite ( 100mev - 50gev ) from grbs revealed an interesting pattern.   the gev emissions are delayed relative to the onset of the prompt mev emission and they show a constant power - law decay long after the prompt emission dies out. while a detectable high energy external shock emission was expected for a long time, the observation that this may be the dominant gev emitted component over the whole burst, including the prompt phase, was surprising. following these observations   @xmath2 proposed a revolutionary model in which there is no magnetic field amplification beyond the usual shock compression. here   we examine the constraints that arise from the observed gev flux on the model by examining the effects of cooling and confinement on the upstream and downstream magnetic fields as well as the influence of inverse compton cooling on the effect of the acceleration and the deceleration of the blast wave hydrodynamics. given the strong low energy ( ir - optical ) radiation fields ( from the prompt, reverse shock and the forwards shock itself ), the magnetic field density should be strong enough in order to
we explore models in which the observed cosmic acceleration is driven @xcite by the flow of dark matter from a higher dimension ( the bulk ) into our three - space ( the brane ).   these models are based on the view that the universe could be a sub - manifold embedded in a higher - dimensional space - time. to test this view, we analyze the existence of a thin three - brane ( randall - sundrum brane ; randall- sundrum space ) embedded in five - dimensional anti - de sitter space and the localization of the graviton zero mode on the 3-brane. for the first time, we show that the observed cosmological acceleration can be explained by the passage of massive mass - less particles from the Brane to the bulk via an energy flow from the brain to the rest of the universe. using a phenomenological approach, we find that the proposed model is consistent with the notion that the present acceleration is due to the migration of massive particles from one dimension into the bulk through a continuum - like energy flow.
temporal cavity solitons ( css ) are ultrashort light pulses that can persist indefinitely on top of a weak homogeneous background in a coherently, externally driven, nonlinear passive resonator @xcite.   they have been observed for the first time in single mode optical fiber ring resonators, where their potential for all - optical buffer applications has been demonstrated ; they have also been shown to underlie the formation of broadband coherent frequency combs in kerr microresonators. however, when multiple temporal css are present in the resonator, one could therefore expect erratic random - walk changes in the separations between the css. in this article  , we describe a universal mechanism that explains such long - range temporal cavity soliton bound states, and we identify several specific physical processes that lead to this scenario. in particular, we consider in detail, theoretically and experimentally, the case of cs bound states mediated by dispersive waves ( dws ) emitted in the normal group velocity dispersion region by temporally css perturbed by high - order dispersion. using the so - called dispersive fourier transform ( dft ) method, we show that these bound states are identified by measuring
the @xmath1p@xmath23 c.o.g.   ( center of gravity ) state in the spin - singlet p - wave sector of the charmonium system has been studied by the belle collaboration @xcite for the first time, and the results are consistent with the predictions of a one gluon exchange ( oge ) breit - fermi hamiltonian, combined with a linear scalar confining interaction at large distances. here   we show that this is not the case, and that the observed splittings of states within these multiplets can be explained by a lorentz - dependent interquark interaction.
we have carried out an absorption study in the 21 cm line of atomic hydrogen in 25 directions in the galaxy.   our observations were primarily intended to study the velocities of the atomic hydrogen absorption features, their linewidths, and in combination with existing high - resolution ( hi ) emission measurements obtain the spin temperature of the absorbing gas. from this data   we obtain the velocity distributions of the absorption features and the spin temperatures of the interstellar gas in the same directions as those seen in optical absorption.
the transport properties of quantum hall bilayers in which the exciton condensate is believed to have formed have largely defied attempts to achieve fully quantitative interpretations.   this conundrum is related in part to the importance of edge states in quantum hall transport@xcite and, as we explain in this paper, to the sensitivity of transport measurements to disorder and to contact properties that are not normally characterized. here   we describe a microscopic mean - field theory for the transport of quasiparticles in the deeply coherent regime of a weak - disorder quantum Hall bilayer based on a scattering formulation of transport theory, @xcite, and on a two - channel contact model which accounts explicitly for the two contact layers.we show that transport properties can be non - trivial even when the current is small enough that the coherence order parameter is time - independent.we develop a simplified version of this picture with a single parameter, which we refer to as _ p - ology_, which allows for virtual occupation of a pair - breaking edge channel and can be used to provide an approximate description of the crossover between strong and weak interlayer coupling regimes.
in many applications, information and knowledge are stored and represented in an information table, where an object is described by a set of attributes.   it is nature for us to fact such a problem that for a special property whether all the attributes in the attribute set are always necessary to preserve this property or not, because using entire attribute set to describe the property is time consuming, and obtained rules may be difficult to understand, to apply and to verify. in order to solve these problems, attribute reduction is required. in this paper  , we construct a dependence space in the context of matroids and apply it to attribute reduction problems.the dependence space is first proposed from the viewpoint of closure operator. then, we study the dependence space by means of matroid theory.    it is interesting to find that the set of consistent sets and the setof reducts of the dependence spaces are the family of independent sets and their bases of the corresponding matroid, respectively. finally,Matroid theory has been widely used in many fields including combinatorial optimization, network flows, and algorithm design, especially greedy algorithm design. as is known, many optimization issues related to rough sets, including attribute reduction, are np -
the availability of cold molecules opens up a new field of low - energy collision studies, in a novel regime where collisions are dominated by long - range forces and resonances.   pulsed molecular beams can be generated with much smaller velocity spreads than is possible with conventional supersonic sources, and therefore offer the opportunity to study scattering resonances at much higher resolution than has been possible in the past. in this paper   we study collisions of rb atoms with nd@xmath0 and nh@x Math0 for collision energies between 0 and 100 @xmath1. using quantum - mechanical calculations of integral elastic and state - to - state inelastic cross sections using the coupled states approximation, we find that the resonant structures of the scattering cross sections for individual partial waves are well - defined and can be explained in terms of the bound states of the rb   nh#nh*@x math0 complex.    we calculate the pattern of bound states near the lowest dissociation limits of the complex as a function of the end - over - end angular momentum and identify the boundstates responsible for the resonances.see research article http://www.biomedcentral.com/
the current state - of - the - art in deep galaxy surveys measure two sets of cosmological observables : the angular distribution of the galaxies and the weak lensing shear induced on their shapes. from these observables,   three types of two - point correlations can be constructed: the angular correlations between the positions of the foreground galaxies, the shear - shear correlations between background galaxies, and the galaxy - sheer cross correlations induced by the association of dark matter with foreground galaxies.   whereas these correlations have so far been analyzed separately and/or with data from different surveys, the joint analysis of these measurements will be feasible from forthcoming surveys. in this paper  , we consider what can be learned from the combined two point correlations. using a generalization of the halo model for the relationship between galaxies and mass, we find that the number of observables available for the joint determination of the cosmology and the relationship among galaxies and light matter are bright.
primordial black holes ( pbhs ) could have formed in the early universe.   it is well known that they would have been of order to the particle horizon mass at their formation epoch and that they evaporate on a timescale of order 100  mev. however, this result is bad news for pbh enthusiasts since it implies that only black holes smaller than @xmath4 g would have evaporated by the present epoch. despite this conclusion, pbh evaporations could still have interesting cosmological consequences. here   we review the formation mechanisms and evaporation constraints on pbh formation and discuss how these constraints can be modified if the value of the gravitational  constant " @x Math0 was different at early times.
the markovian quantum master equation ( qme ) is a key paradigm for the study of nonequilibrium statistical physics.   the structure of this framework is transparent, the generality of its derivation is sufficient, and the approximations applied are well defined, especially when the system hamiltonian is time - independent. in recent years, however, the quantum dynamics driven by _ time - dependent _ external field has been an area of growing importance in various contexts, such as adiabatic quantum computation, quantum annealing, quantum heat engines, bose - einstein condensates in optical lattices, and semiconductor quantum dots because the external driving is essential for the use of the quantum systems as nontrivial physical resources. despite the recent experimental demand,   no general way of rigorously constructing theMarkovian qme is currently known for the time - dependant system ham Miltonian, @xmath1  @xcite.. in this article, we settle this long - standing debate by studying the conditions to justify the markoviaqme with @x Math1 in a general manner. under the weak - coupling approximation ( wca ), we introduce an explicit
the evolution of protoplanetary disks around young stars provides the raw material for planet formation.   recent observations of planets around m  dwarfs ( @xcite ) suggest that cool stars are the typical planet hosts in the galaxy, but how do these planetary systems differ from those around sun  like stars?   lacking observational data, some models of planet formation assumed that disk properties are independent of the stellar properties. however, recent observational studies have revealed stellar   mass  dependence for most disk properties. here   we present results from a statistical study of spitzer / irac colors of the complete census of the chamaeleon  i star - forming region and use a grid of simple disk models to demonstrate that the difference in the distributions of irac color distributions is well explained by the lower occurrence rate of flared disks around the lowest  mass stars. using this model, we find that the low mass stars have flatter disks than the high mass stars, which is consistent with the observation that the average lifetime of optically thick dust disks around cool stars and brown dwarfs seems to be at least a factor of two or three longer than around sun ’s  like’s.
the anderson localization of quasi one - dimensional ( 1d ) matter waves in the presence of a weak disorder has been experimentally demonstrated by quasiperiodic potentials of ultracold atoms.   these experiments pave the way to the observation of new phenomena and shed new light on long standing problems, amongst which the question of possibleanderson localization in presence of interactions. in the present paper   we consider the case of a quasi 1d, weakly interacting bose einstein condensate propagating through a disordered potential. for small velocities  , perturbation theory shows that the superfluidity is preserved, e.g., the flow is dissipationless and with a perfect transmission. in contrast, in the high speed limit, where the kinetic energy dominates over the interaction energy, the transport properties of the bec are deeply altered, and tend to those of the non - interacting gas, displaying an exponential damping of the transmission with length @xmath0, a behavior characteristic of the strong anderson localized state. in between, it is shown that stationary scattering solutions do not exist : one reaches a regime of time - dependent flows with more or less complex density excitations.
we report an analysis of diffuse @xmath0-ray emission observed in the third galactic quadrant by the lat @xcite using the leiden / argentine / bonn galactic h  survey.   we find that the emissivity per h  atom and the inferred cosmic - ray ( cr ) density are affected by up to ~2.5  kcal / mol for the atomic gas in the interarm, lower - density region located between the local and perseus arms at a few kpc from the solar system, and by ~1.4  kcal/mol for the interstellar gas in each arm.    the results are compared with predictions by a cr propagation model based on the observations and the model.
the x - ray spectra of mcg@xmath06 - 30 - 15 by the  advanced satellite for cosmology and astrophysics  ( asca ) reveal a broad iron line with a velocity width of @xmath2 and a profile which is skewed to low energies.   the origin of the broad iron lines has been the subject of intense debate for the past few years, and several models have been proposed to explain the observed spectrum. in this review,   we consider the most recent developments in the comptonization model of the iron line formation and discuss the constraints on the model that are imposed by the presence of strong gravitational fields.
the infrared ( ir ) emission from active galactic nuclei ( agn ) originates from a clumpy dust torus around the central black hole and accretion disk.   this theory has been used to explain the observed type 1/type 2 dichotomy of unobscured and obscured agn, but the true geometric distribution of the emission was never scrutinised up until recently. in this paper  , we present the radiative transfer model _ cat3d - wind _ of a clumping disk and outflow with the geometry and dust composition built upon the hypothesis outlined in @xcite that the ir emission from agn comes from a compact, geometrically thin disk in the equatorial region of the agn. using the model, we show that such a configuration reproduces key observational characteristics of agn including the overall ir spectral energy distributions ( seds ), the types 1/2 dichotomy, the observed disk plus polar emission structure, and the @xmath1 bump seen in many unobscurred agn.see research article http://www.biomedcentral.com/1471-7007/9/8/6/17 for more details.
the existence of dual agns ( dagns ) in the universe and their demography provide an important probe not only of the hierarchical galaxy formation models but also of the triggering mechanisms of nuclear activities and the assembly history of massive black holes ( mbhs ).   it has been recently reported that roughly 0.5%-2.5% of the @xmath2 type 2 agns are kpc - scale dagn, which is a frequency that is more than an order of magnitude lower than that expected from the observed major merger rate of galaxies if one makes the assumption that each major merger would yield a dagn. here  , we construct a phenomenological model to address this discrepancy by taking into account several factors, including the observed frequency of kpc- scaledagns, the types of galaxy mergers that can trigger the nuclear activities of both progenitors, when and where significant nuclear activities are triggered, and the duration of the nuclear activity before the merger of the two merging galaxies. using our model, we show that the observational frequency of dgns is consistent with current observational constraints on the merger rates of galaxies and the scenario that major mergers of galaxies lead to significant nuclear Activities.
this paper is devoted to the analysis and large - time behavior of solutions of the equation  = ( 1-x^2)(x - m(t ) ) f, where the unknown @xmath0 is a time  dependent probability density which may represent the density of opinion in a community of agents.   the mathematical methods we use are close to those used in the context of kinetic theory of nonlinear friction equations @xcite, and made popular by the mass transportation community. in the next section   we introduce the main properties of the model, which justify the treatment in terms of a suitable weak formulation.the qualitative analysis is given in sections 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 49, 50, 51, 52, 53, 54, 55, 56, 57, 60, 61, 62, 63, 64, 67, 68, 69, 70, 72
factorization is a fundamental concept in quantum chromodynamics.   it allows the applicability of perturbative methods to the calculation of scattering amplitudes and cross sections of hadronic processes. at high - energy ( regge limit )  , the scattering amplitude is suitably factorized in rapidity - space, and the coefficient - functions and matrix elements of non - local operators of the operator product expansion at high energy, contain perturbation and non perturbable contributions. here   we illustrate the logic of the ope at high energies when applied to the t - product of two electromagnetic currents which will be relevant for dis process.
the recent observations of and scalability concerns with the dynamics of the bgp routing table size growth, @xcite, bring up the question of how small the routing table sizes for distributed routing on realistic massive graphs can be made  in principle.   in other words, what are the  fundamental  limits of compactness of graph - theoretic routing in such networks?   we review the results relevant to our work in the two separate subsections.
we generalize the properties of the low - lying elementary excitations ( quasiparticles ) of quantum chromodynamics ( qcd ) based on the bardeen - cooper - schrieffer ( bcs ) theory of fermionic many - particle systems to an imbalanced system.   we show that the effect of the dressed gluons on the thermodynamic potential, specific heat and effective mass of the system is similar to that of the normal phase of quarks in the bcs theory. however, the temperature of the superconducting phase @xcite is much lower than the expected value due to the presence of a color - flavor locked phase where all the colors and flavors are paired. by contrast, the energy of the quark - gluon plasma at high densities is significantly higher than that predicted by the standard bcs model, which is explained by the fact that the quarks are not exposed to the same chemical potentials as they are at low densities.
we study experimentally the dependence of the electron effective mass on quantum well ( qw ) width for cdte/(cd, mn)te heterostructures grown by molecular beam epitaxy on an ( 100)-oriented cdte substrate.   the structure contains four consequently grown cdte wells with width @xmath930, 9, 3.6 and 1.2  nm separated by 50-nm - thick cd@xmath7mn@x Math8te barriers from each other, separated by a barrier of 50  nm. in order to obtain two - dimensional character of the studied resonances, the optically detected of cyclotron resonance ( odcr, or odr ) technique has been used. under microwave or far - infrared irradiation, the emission of the photoluminescence intensity under absorption of microwave orfar - infrared radiation by free carriers is strongly dependent on the width of the quantum wells. at the same time, the effective masses of electrons and holes are not significantly affected by the qw width.
we investigate whether and when segregation can emerge spontaneously in a system of competing double auction markets.   we develop a stylized model of a double auction using experience - weighted attraction learning ( ewa ) to learn from the payoffs received for past actions and thus optimise future trading. by analysing the equilibrium state of the system using a fokker - planck approach  , we show that some markets tend to focus on attracting specific traders, and some traders prefer to trade at a specific market although no such fixed propensities were imposed from the beginning. this observation is consistent with the results of an experiment based on cat market design tournaments, where segregated states were observed in the co - adaptation of markets and traders.
near earth asteroid ( 29075 ) 1950 da was first discovered in 1950 by c. a. wirtanen at lick observatory @xcite and then lost for more than 50 yr. in december 2000   the asteroid was rediscovered at lowell observatory - loneos as 2000 yk@xmath3 and subsequently recognized to be 1950 da. in 2001, 1950 da experienced an earth close approach at 0.05 au and radar observations were obtained from arecibo and goldstone.   these radar observations significantly reduced the orbital uncertainty and allowed long - term predictions of the probability of an earth impact of 1950 da in march 2880. because of the decisive contribution of the yarkovsky effect,1950 da belongs to a class of " special objects ", which also includes asteroids ( 99942 ) apophis @xcites and ( 101955 ) bennu @xcits.    each of these objects presents unique features and demanding tasks. in particular, for 1950   da we are pushing the impact prediction horizon for a time interval that is four times longer than ever analyzed for any other asteroid. performing the impact hazard assessment requires a specific effort and the development of ad hoc techniques beyond
we propose a network coding based low - density parity - check ( ldpc ) code for the cooperative uplink system with multi - source and one relay ( @xmath1 system ).   the code is designed to address the problem where the capacity gap between the source - to - relay channel and the source- to - destination channel becomes larger, which is observed in the triangle model of the cooperative single source channel (@xmath2 system ) using full - duplexing relay. within each of these channels,   a bilayer ldPCP scheme is utilized to approach the system capacity. however, the performance is decreased as the capacity gaps between the sources and relays become larger. in this paper  , we investigate a network codes based multi - edge type Ldpc, which we refer to as ncmet - ldpcs, for the @x Math1 system. through the exit chart, we see that the network coded parity check digits produced by the relay provide more extrinsic mutual information ( emi ) for each source, relative to a separate round - robbin scheme.graphical abstract
the present implementations of interaction models can not describe all observed air shower properties with a good precision.   the uncertainties in predicting shower properties are mainly a consequence of uncertainties in the modeling of hadronic interactions, since these can not be obtained directly from qcd calculations. to investigate the importance of Hadronic interactions in the na61/shine beam energy region for ground - based shower observables we performed simulations with different interaction models and varied the transition energy between the low- and high - energy models. using corsika  @xcite, eight sets of proton showers of with a uniform @xmath5 distribution, @x Math6 being the zenith angle ranging from 0 to 60 degrees,   were generated by combinations of generators describing the low energy hadronic interaction, fluka @xcite and gheisha  @xaite, and Generators describing the high energy hadronics, qgsjet ii  @xfite and sibyll  =  2.1  @xeite.    the results show that the number of particles predicted with different assumptions already with 100 showers is significantly different ( p < 0.05 ). erythroscopic observations at the pierre aug
we extend the analysis of spectrogram analysis of ship wakes in @xcite to include the effects of a finite - depth fluid on the linear dispersion relation.   we show that the location of high intensity regions on the spectrograms is affected by the depth of the fluid and the width of the pressure distribution relative to the water depth, where the regions with high intensity favour higher frequencies along the dispersion curves for smaller pressure widths. using experimental surface height measurements taken from a model test basin at the australian maritime college, we validate the new linear and second - order dispersion profiles against spectrographic data collected from the same body of water.    we observe trends in the experimental spectrogram trends for different sailing speeds and hull shapes, and provide possible explanations for these trends in terms of linear and nonlinear frequencies.. finally, we explain certain periodic patterns in the spectrogram for vessels with a high aspect ratio in termsof wave interference effects.
background : previous researches have predicted the outcome of u.s.   presidential election using twitter. some of them proved that twitter data can complement or even predict the poll results. in this research, we analyze the sentiment on tweets about 2016 u.S. presidential candidates and build a naive bayesian predictive model for each candidate and compare the prediction with realclearpolitics.com.methods:we gathered 371,264 tweets using _ twitter streaming api _ on _ tweepy _   @xcite since december 16, 2015 until february 29, 2016. to collect the tweets, we used Twitter streaming api and set keywords for each campaign candidate. then we preprocessed the tweets using a complex preprocessing method ( removing urls, mentions, retweets, hashtags, numbers, stop words, emoticons, phone numbers, html tags, mentions ) and tokenized them by adding _ not _ on negative words. finally, we built a neural network to predict the vote outcome of each candidate based on the sentiment of the tweets. after training the model using the models, we compared the performance of our model with the best performing recent studies from three recent researches.results:we
a feshbach resonance arises when a bound state of a closed scattering channel is coupled to the scattering continuum in the entrance channel.   the position of the resonance is tunable by varying the strength of the applied magnetic field, since the open and closed channels have different magnetic moments, and therefore experience different zeeman shifts. here   we derive analytical results fully characterizing both the bound and scattering states of an atom pair in an optical lattice near a feshach - resonance. using a two - channel model with one open channel and one closed channel, which is adequate to describe the physics of both the scattered continuum and the bound states of the system for an isolated resonance  , we show that the presence of an open channel bound state leads to a fano profile in the transmission probability in the bound state spectrum, which can be explained by the existence of a strong repulsive interaction between the atoms in the closed channel and the atoms at each lattice site. on the other hand,   there is no such case for the scattering state, where the direct scattering process in the open channel interferes with the resonant scattering proceeding via the locked channel.
the dc squid is a versatile quantum circuit displaying several energy levels with tuneable anharmonicity. in the two level limit,   the qubit is a phase qubit whose decoherence has been characterized @xcite. with smaller an Harmonicity, microwave excitation induces complex dynamics which involve many levels @xcites.   readout of the quantum state is one of the key issues in quantum circuits operation. in this article  , we present a complete characterization of our measurement performance for the ground state detection of the dc squid using adiabatic dc flux pulses. excepting a small correction due to residual noise on bias parameters, the experiment is consistent with macroscopic quantum tunnelling theory and the measurements are performed within a few nanoseconds. by neglecting the coupling terms between the two directions along the escape direction and the transverse one, a simple relaxation model successfully accounts for measurement performances.
we present the first numerical solution of the realistic lengyel, rabai and epstein ( lre ) model of the chlorite - iodide - malonic acid ( cima ) reaction - diffusion system in two dimensions.   we use the lre model to investigate the formation of one - dimensional stationary structures along the boundary feed gradients and their linear instability to transverse symmetry - breaking ( turing ) patterns. using a thin - strip open reactor, we determine the branch of the bifurcation diagram corresponding to the transition to stripes in this system, a result which can be directly investigated in experiments based on the cdima system.
we have undertaken an extensive numerical study of the stability of the hypothetical uranus trojan cloud around the equilateral equilibrium points of neptune and saturn in the model of the outer solar system ( oss ).   the results show that the instability of the cloud is dependent on the inclination of the body, and it is found to be stable for the whole range of inclinations up to about @xmath12. however, for the first few years after the discovery of a jupiter trojan some of the trojans appear to be unstable even though they are in stable orbits with respect to the sun and the four gas giants.
we study the excited states of a heavy - light meson on a lattice using qcd calculations.   we find that the p - wave spin - orbit splitting is small, but the d - wave split is non - zero and positively correlated with the mass of the light quark. in contrast, the sos of the two lower p - waves are very large and do not agree with the experimental results..see research article http://www.biomedcentral.com/1471-2148/7/9/8.
the performance of cell - edge mobile users ( mus ) or worst - case mus in orthogonal frequency division multiplexing ( ofdm)-based cellular networks is a major challenge for next - generation wireless networks.   we provide a general theoretical analysis of the performance of the worst-case mus in an ofdm - based cellular network using stochastic geometry model. by modeling the location of the base station ( bs ) by a poisson point process ( ppp ), we derive the coverage probability and the signal - to - interference - ratio ( sir ) under i.i.d. rayleigh fading on all links, we compare our analytical results with those for the typical mu derived by andrews et al. from these results, we conclude that the coverage probabilities of the bad - case mu decrease down to 23% of that of the normal mu at the target sir of @xmath0 db when the number of nearest bss is 1.0 db. also, we show that the spectral efficiency of the Worst - Case mu decreases down to 19% after applying a coordinated scheduling ( cs ) scheme.
the two - component jet model has been frequently used to interpret data of active galactic nuclei ( agns ) and gamma - ray bursts ( grbs ).   recently, much attention has been paid on the discovery of the hard x - ray transient event swift j16449.3 + 573451, ( " sw j1644 + 57 " hereafter, @xcite ), which has been interpreted as a tidal disruption event ( tde ) with jet. here  , we review the recent advances in the understanding of the physics of launching a relativistic jet / outflow from tde events.
the effects of external forces on the diffusion of particles in periodic potentials are studied by means of numerical simulations of the fokker - planck equation for the coordinate and velocity distribution function in @xcite.   the results show that at low friction the appearance of locked solutions ( in which the particle oscillates around one minimum of the potential ) and running solutions ( where the particle travels through many potential periods, not getting trapped at separate minima ) solutions is important for the particle ensemble behavior. at small temperatures   running solutions appear abruptly at the external force value exceeding certain critical ; at smaller forces a single class of solutions ( locked ) is realized.
high - efficiency solar cells can be fabricated cheaply from the liquid phase of hybrid halide perovskites  @xcite, where the organic cation is taken by an organic molecule, in this case methylammonium, ch@xmath0nh@x Math0.   the success of such compounds is partly due to the fact that they can be tuned by controlling their structural order and composition. here   we conduct density functional theory ( dft ) calculations for these compounds in the cubic phase, by taking into consideration the experimentally reported evidence of the fast rotation of ch@ xmath0 nh@Xmath0pbi@x maths0 molecules above room temperature. at low temperature the crystal adopts an orthorhombic structure, in which the methyrammonium group is pinned and can only rotate along the c - n axis. as the temperature is increased and the material progressively assumes a cubic structure, by passing through a tetragonal one, the ch+@x math0 molecules become free to rotate between the octahedral cages. using van der waals interactions, we find that such symmetry lowering has profound consequences on the electronic structure, namely that the band
in this review article, we consider two prototypical situations : ( i ) the approximation of the homogenized tensor in the context of stochastic numerical homogenization, and ( ii ) the multiscale finite element computation of the solution to an ( harmless ) equation posed on a randomly perforated domain.   both situations are characterized by the presence of a random character in the partial differential equation, which can be encoded in the coefficient  @xmath3, or in the right - hand side @xmath2, and/or in either the domain itself. in both cases,   the problem is solved numerically by approximating the solution using a number of methods that explicitly treat randomness in such partial differential equations. in the present review article  , we would like to concentrate on a somewhat alternate strategy : _ not attempt to simplify the dependency upon randomness, but embrace the difficulty arising from it.we discuss the advantages and disadvantages of each of these approaches, and show that they do not marry so well with randomness when it comes to practical computations.
in @xcite, h.  jonas established a couple of results pertaining to asymptotic transforms, w - congruences, conjugate nets and laplace cycles of period four.   this article explores discrete versions of these theorems in the field of discrete projective differential geometry. it blends in with and extends more recent research on discrete conjugation nets, their laplace transforms, discrete w-congruences and, in the limiting case, also discrete asympotic nets.
the rosat all - sky survey led to the discovery of many lithium - rich stars.   it was assumed that they were low - mass pre - main sequence ( pms ) stars, as they were located at the same distance as previously identified classical ttauri stars ( ctts ) in the respective star forming regions. recently, briceo et al. and   others have argued that a dispersed population of young zero - age - main - sequence ( zams ) stars with ages up to 100 myr could account for the observed properties of the rosat sources. in order to solve this dispute, we study the hipparcos data of 21 li - rich rosat source counterparts, discuss the kinematics, and present their evolutionary status.
x - ray flashes ( xrfs ) are intense transient bursts of x - rays, similar to gamma - ray bursts ( grbs ) but characterized by a stronger x - ray than @xmath7-ray fluence.   it has been speculated that they are linked to supernovae ( sn ). in this paper  , we model the observed light curve ( lc ) of xrf  030723 using different sn   ic models, both normally- and hyper - energetic, and explore various redshifts to determine the possible range of the parameters of the sn associated with the xrf. for each model,   the lc is modeled as a bolometric light curve at a redshift ranging from ~200 to ~4000. assuming that the sn in xrf  is of type ic ( sn  ic ), by analogy with the cases of grb - associated spectroscopically confirmed supernova ( sne ), we computed synthetic @x Math21 bolometric lc simulations of the exoplanet at a variety of redshifting to determine its possible redshift limits. on the basis of these simulations, we find that the maximum value of the lorenz
a model with adiabatic matter creation was proposed firstly in order to interpret the cosmological entropy and solve the big - bang singularity problem @xcite.   the basic idea is to modify the usual energy conservation law in open system in the framework of cosmology, which adds a balance equation for the number density of the created particles to the dynamic equations of the universe. in this paper  , we use recently 186 sne ia sample@xcite, combined with the observational @xmath2 data from the differential age measurements of galaxies @Xmath2, the cosmic microwave background ( cmb ) and bao data @xaite, to test the cos molecular model with matter creation and make constraints of the parameters. as a comparison, the model with either matter creation or cosmology constant is also examined.
we have developed a method for calculating massive two - loop feynman diagrams.   we show that for any external kinematics and internal masses, we can reduce every two-loop amplitude for a process due to any renormalizable interactions into a set of ten scalar integrals and their derivatives. in the following section  , we discuss the steps and arguments needed to perform a tensorial decomposition.we show that there is a small set of basic functions which are needed, which have simple, one - dimensional integral representations. by partial differentiating with respect to @xmath9, there is in principle only one basic function arising from@xmath10, although for convenience one may add @x math11.    it is clear that different interactions and different graphs will give different polynomials of feyn mann parameters to the numerators, and also different tensor integrals. using this formalism,   it is possible to obtain rates for exclusive processes, without the need to integrate over the whole final - state phase space.
we study the consistency of maximum likelihood estimation for a family of parametrized families of deterministic systems observed with noise.   we find that the statistical properties of the family of dynamical systems are consistent with those of the observed data, and we show that this consistency is particularly strong for hidden markov models ( hmms ) in which each parameter value corresponds to a stochastic system observed with noisy observations. under some additional conditions,   our results are even more consistent for non - markov systems, where the hidden state space and the observation space are finite sets. using these conditions, we also establish several connections between well - studied properties of dynamic systems and statistical properties relevant to maximum likelihood estimating the unknown parameter in a model with an unknown parameter. finally, we apply these results to some examples, including shifts of finite type with gibbs measures and axiom  a attractors with sinai  ruelle   bowen measures.
we present a new equilibration scenario of the increasingly strongly interacting parton plasma ( isipp ).   the new scenario arises out of the previously neglected running of the coupling. in high energy nuclear collisions, the interactions in the early stage are pretty hard, so perturbative qcd is applicable. by combining boltzmann equation with the relaxation time approximation for the collision terms, c(p, ) = -  and construction of the latter again explicitly from qcd matrix elements of the simplest elastic and inelastic interactions, we can solve for the distribution function @xmath11 and hence find out the time evolution of the Parton plasma. using the one - loop running coupling formula, we show that the equilibrium of quarks and gluons in the plasma is faster and improved when the system is driven out of equilibrium but only for quark and antiquark are there any improvements towards the end of the time evolvement. to end, we have three news to report on three different particle productions.
the double  lepton polarization asymmetries in the baryonic @xmath0 decay induced by the flavor  changing neutral current ( fcnc ) are investigated using a general form of the effective hamiltonian, including all possible forms of interactions.   the analysis is carried out at quark level and the results are compared with those of the experimentally measurable quantities such as branching ratio, polarization and single lepton polarization in @xcite.
electron energy - loss spectroscopy ( eels ) has been used to investigate the electronic excitations of pentacene single crystals in transmission with unprecedented energy resolution and at low temperature ( 20 k ).   the results show that the exciton dispersion in the @xmath0 reciprocal lattice plane is highly complex and can not be rationalized on the basis of molecular frenkel excitons only. instead, a mixture of frenkel and charge transfer excitations are responsible for the observed behavior of the lowest lying singlet excitations in the crystal lattice planes.. the electron energy loss spectra of the excitation spectrum obtained by eels at energies of 85 mev and 0.03@xmath8, respectively, are compared with those obtained by means of x - ray diffraction and density functional theory calculations. using these calculations,   it is shown that the energetically lowest lying excitations occur in the crystalline plane of @x Math0/xmath1-conjugated compounds, where the highest energy satellite features are the vibrational vibrations as well as the charge transferexcitons. moreover, the present investigation provides insight into the complex behavior of higher energy satellite
we have developed algorithms to compute templates that take only one - half of the computational time to filter out the detector data through the gravitational wave ( gw ) signal from binary black holes ( bh ) and neutron stars ( ns ).   this is achieved by solving a pair of ordinary differential equations in the time- and frequency - domains, and by using explicit analytic expressions of the fourier components of the phasing formula @xcite that constitute an accurate representation of the time - domain signal truncated at, or slightly prior to, the last stable orbit ( lso ). in the frequency - domain   we have also derived explicit analytic functions for the amplitude and frequency of the peak gravitational wave emitted by the system when it merges into a single spinning kerr hole.
josephson effect is an example of macroscopic quantum phenomena and is of fundamental importance in condensed matter physics.   recently, there has been a growing interest in understanding coherent transport phenomena in hybrid heterostructures involving s - wave superconductors and non - superconducting nanostructured  @xcite. in this paper  , we study josephton effect in superconductor - semiconductor nanowire - supercond conductor heterostructure ( sc - sm - sc ) where the system consists of a semiconductornanowire with strong rashba spin - orbit coupling(soc ) subject to a large in - plane magnetic field. by employing a combination of analytical and numerical techniques, we develop a quantitative theory for the coherent transport through the nanowires in the clean limit by employing two different analytical methods : local density of states ( ldos ) and tunneling conductance ( t conductance ). using the ldos method, we show that the helical phase in the semiconductor Nanowires can be identified by a sharp decrease of the supercurrent as one increases an in - Plane magnetic field ; however, the long - junction limit is not affected by any change in the nan
we show that any two - dimensional ( 2d ) measurement on a 2d hilbert space can be realized by local operations and classical communication ( locc ).   this is true for any two pure orthogonal states in finite - dimensional systems, no matter how entangled they are. to prove this, we consider the case of two quantum states @xcite and find that they can be optimally distinguished using only locc.
we present the first results from follow - up observations with the _ suzaku _  observatory @xcite of the active galactic nuclei swift j0601.98636  and swift j0138.64001 , which were detected in the _ swift_/bat survey at energies above 1015 kev.   these targets are essentially randomly selected from a bright _ swift   agn sample for which soft x - ray ( @xmath910 kev ) spectroscopic observations had never been performed, and are thus reasonable representatives of unknown agn populations selected by hard x - rays above 15 kev as long as the column density is less than log@xmath1  @x Math8 @x math6.    we also present an optical spectrum of swift j0801.8600  taken at the south african astronomical observatory 1.9-m telescope.
non - gaussianity is a key parameter in the search for the origin and evolution of cosmological structures.   it is often taken to be of the so - called local type and is parameterized by the constant dimensionless parameter @xmath7 @xcite. here   we use the power spectrum from the nrao vla sky survey ( nvss ) and the quasar catalogue of the sloan digital sky survey release six ( sdss dr6 qsos ) to revisit the constraints on the primordial non - gaussianity from these two large - scale structure tracers using the power spectra instead of the correlation function@xmath24, which is commonly used as a proxy for the observed auto - correlation function. while the angular correlation function and the angular power spectrum are spherical harmonic pairs, each of the two measurements is affected by systematic errors in different ways. with the exception of the sdss ii lrg photometric redshift survey, megaz - lrg, which has been used to investigate the late integrated sachs - wolfe effect,   the results show that the observed autocorrelation function is only slightly affected by the survey mask but the power
the long - time behavior of the period of an eclipsing binary could reveal the presence of another component orbiting with the eclipsing pair around the common center of mass.   the motion around the barycenter causes apparent changes of the observed binary s period with a period corresponding to the orbital one of the third body, called the light - time effect ( or light - travel time, hereafter lite ). in this paper   we present new times of minima based on ccd observations ( kwee - van woerden ( @xcite ) method ) of three systems of contact ebs, of w  uma or @xmath13  lyr type, with components of similar spectral types ( ranging from f to k ). for some of the systems studied in this study the spectral types of the secondaries are known with a low confidence level, light - curve analysis is missing and spectroscopy has never been done. using the new measurements, we show that the apparent orbital period changes in these systems are caused by magnetic activity cycles and convective envelopes.
entanglement, nonlocality and quantum discord  ( qd ) are all different but somehow related aspects of the quantumness of the correlated composite quantum systems.   entanglement is a kind of quantum correlation and determines whether the given state is separable or not. on the other hand,   quantum discord is found to be nonzero for some separable states and it is believed to be useful in the deterministic quantum computations with one pure qubit context. here   we present a new study of the dynamics of quantum correlations between two qubits coupled to a common environment modelled by ising spin chain in a transverse field and discuss the effects of decoherence and dissipation on the behavior of quantum discord as well as entangler sudden death.
the core collapse of massive stars is the fate of the stellar evolution, which leads to the variety of explosive phenomena, including the formation of compact objects and the neutrino burst.   the progenitors of the core collapse supernovae are thought to form black holes after the supernova explosion. in this review,   we discuss the results of the recent numerical simulations of the failed supernova involving the prompt black hole formation by @xcite using the equation of state ( eos ) with hyperons for the initial mass of @xmath420@xmath5 and the solar metallicity of ~1.2  mpc.    the results show that the rate of the blackhole formation depends on the model parameters of the proton - based model. while the delayed black hole formations occur after the faint ( perhaps even undetected ) supernova explosions, the promptBlackhole formation occurs when the super Nova explosion fails.
short duration gamma  ray bursts ( sgrbs ) are the electromagnetic counterpart to the coalescence of compact binary systems, such as double neutron stars ( ns ) and neutron star and black hole ( bh ) mergers.   a potential means to distinguish between these two classes of progenitors concerns the signature of the disk and jet precession in the electromagnetic signal, i.e. the sgrb itself. here   we search for this kind of quasiperiodic signal in the data of the brightest s grbs detected with the _ fermi_/gbm, the _ swift_ burst alert telescope, and the _ compton gamma ray observatory - burst and transient source experiment, exploiting the exquisite time resolution available with these instruments. using a dedicated search technique, we find 18 out of 160 sgrs with @xmath0@xmath1  s  s that have a precession period of ~5  ms at the beginning of the burst and ~10  ms after the end.    we also find an additional 12 events with ~3  ms precession at the start of theburst and ~2  ms later, which are likely to be due to
the magnetization of a two - dimensional electron gas ( 2deg ) in a lateral superlattice, defined by a potential periodic in two directions ( electric modulation ), is calculated for a finite array of quantum dots using a mott - hubbard model for the electron - electron interactions, both intra - dot and inter - dot.   the results show that the bulk contributions to the magnetization are strongly dependent on the presence or absence of the exchange interaction in the models supporting the view that magnetization is an ideal probe of the many - body effects in a 2deg@xcite magnetization.
the quantum hamiltonian ( wheeler - dewitt ) constraint of einstein - hilbert gravity is a densely defined operator on a certain space of states and which is anomaly free on diffeomorphism invariant states.   thiemann @xcite proposed a definition of this constraint that is self - consistent, well defined, and can be used to calculate quantum versions of the commutator of two ham Miltonian constraints. in the preceding paper @xxcite, thieman showed that the algebra is consistent at this level : his quantum version of both the left and right hand sides of (  ) vanish on diffed states. however, it is still not clear whether the resulting theory is connected with the physics of gravity. in this paper  , we show that the original quantization of this function yields the zero operator on the larger space @xmath11, so that one could consider the calculation consistent. as a result,   the quantum commutators of the hamiltonic constraints are nonzero.. however, there exist regularization ambiguities that allow us to propose quantum variants of @x math14 and @x maths9 that are non zero
we investigate the stability properties of cc solutions of the gradient fluid equations for a subclass of the rivlin - ericksen - green multipolar fluids treated in bellout @xcite that has energy density given by .   the equations of motion for gradient fluids are obtained from the eulerian form of hamilton s principle introduced in holm, marsden and ratiu ( foias@xcite ), where  is the order of the velocity gradients appearing in ( /).for cc solutions in an unbounded domain, the fluid velocity is linear in the spatial coordinate and the pressure is quadratic.the cc solutions may be regarded as the first term in a taylor expansion in space, around a stagnation point of the flow in a moving frame. using the theory of elliptic instability to investigate the exact nonlinear growth rates when cc solutions interact with a wave packet whose phase is frozen into the cc flow for gradient liquids of degree, we find that the rate constants of the growth rates are approximately 1.5  kcal / mol for the whole wave packet and about 2.5
magnetic helicity is a useful tool in understanding large scale dynamo action.   it is important because it is conserved in the limit of vanishing resistivity, and it has been used to explain the final saturation field strength of helical dynamos in periodic domains. in the present paper   we use similar ideas to obtain a more detailed understanding of the case with an imposed magnetic field. using the model equation governing the evolution of the magnetic helicity in a periodic domain in the presence of an imposed field, we show that the magnetization of the fluctuating component of the mean - field is gauge - dependent, and that the dynamic field is suppressed above a certain field strength. by taking into account the time scale of the imposed field  , we derive a model equation for the dynamics of the parametrization of the electromagnetic helicity for different imposed field strengths.the model equation is then used to derive the differential equations governing the phase transition from the nonresistive to the resistive limit of the current density of the fluctuationsuating magnetic field, and the diffusion of the helicity between the two parts of the dipole force. as a result, we find that the dependence of the gradient term on the
we present a study of the integrated spectra of 23 normal galaxies in kennicutt s ( 1992a, b ) spectrophotometric atlas.   we find that the spectral sequence of almost all galaxies is arranged along a quasi - linear sequence which we call _ spectral sequence_. the few outliers are sc and sm / im galaxies with spectra dominated by nebular emission lines. for these galaxies, emission lines associated to ongoing star formation   dominate the spectra. using a revised model of the star formation time - scale of a galaxy, bruzual & charlot ( 1995, hereafter b&c ) suggest that one single parameter may be responsible for the global regularities in the integrated spectrum of normal galaxies.
the allen - cahn / cahn - hilliard model ( ac - ch model for short ) is a diffuse interface model which combines and extends two famous diffuse interface models : the allen  cahn equation and the cahn   hilliard equation.   both have been applied successfully to model segregation, precipitation and phase change phenomena in alloys and liquid mixtures in materials science, geology, physics, and biology. here   we study an extension of this model with a particular ansatz for the elastic energy.. the new model is valid for @xmath7 dimensions and provides a basis for the generalization of further existing isothermal diffuse interfaces models.
complex networks are ubiquitous in nature.   they are seen in phenomena studied by physicists from resistor networks to polymer contact structure to spin interactions in disordered systems, in engineered systems ( e.g., the internet and the power grid ) and in the biological world from the intra - cellular signaling system to neuronal networks to ecological food webs. while both modular and hierarchical features are increasingly being reported in a wide range of systems, it is still not clear what role such patterns play in the dynamics and function of the corresponding systems. in this paper   we show that in a hierarchical modular network of oscillators arranged into @xmath1 levels, there exist distinct time - scales of the synchronization dynamics. for example, the oscillators belonging to the elementary modules synchronize earliest, followed by those of the more strongly connected modules at the top of the network. on the other hand, for the intermediate modules,   the synchronized oscillators tend to synchronize earlier than the non - synchronized oscillators, as indicated by the higher order of the average path length and the lower order of their clustering coefficient. these results suggest that the existence of modules can give rise to two distinct times - scales for the dynamics on such networks :
a stochastic equation for the critical dynamics of a bose - like system in the presence of a random velocity field was proposed in @xcite.   the model is based on a modification of model e, which is relatively simple and corresponds to the stable infrared - scaling regime in model f. the renormalization group ( rg ) approach is used to analyze the model using the standard martin - siggia - rose formalism and dimensional regularization around its critical dimension four with the standard @xmath2-expansion. by means of the one - loop calculations of the rg functions,   we show that the model can be described in the vicinity of the critical points of the considered system by the following equations : order parameter, order parameter = internal energy and density, temperature = temperature / viscosity, and velocity = fluctuating velocity field. as a consequence, the equilibrium fluctuations of velocity are included in the model, and the phase transition into the superfluid state is characterized by the existence of an equilibrium turbulence regime.
theoretical models of the evolution of star - forming disks at @xmath0 have suggested that they evolve into giant clumps that migrate to the centers of their galaxies, where they become stellar - dominated and sink to the center of the galaxy.   these models have been interpreted as supporting the picture of long - lived migrating clumps, but none of the simulations reported so far include strong galactic winds, which as noted already are directly observed. in this paper  , we show that incorporating galactic superwinds resulting from stellar feedback into the existing theoretical picture can have important implications for our understanding of @x Math0 disks and their evolution. using hydrodynamical cosmological simulations, we use a phenomenological model for the generation of galactic winds to test a scenario in which galacticsuperwinds are generated by a large number of stars, including those that have migrated from the outermost regions of the disk into the central region of the core of the system.. we find that the simulation results are consistent with observations, while the simulations show that the dynamical strength of the galactic winds depends on the presence of a redder / older component within the system, not the size of the clump.
the influence of the reciprocity of the phase of two counterpropagating spin waves excited by a microwave current through an antenna mounted on top of the magnetic film significantly depends on the used geometry. in the case of reciprocal backward volume magnetostatic spin waves ( bvmsws )   these waves propagate with identical amplitudes.   if one excites the non - reciprocal surface spin waves this amplitude symmetry is drastically distorted and spin - wave propagation in one direction is strongly suppressed. in this article   we demonstrate that the phase symmetry is distorted when the reciprocal bv msw is excited and is preserved in the cases of the non-reciprocal surface spin wave ( mssw ). as a measure of the initial phase symmetry we used the difference in initial phases of the two counter Propagating waves excited using the same transducer.. the results show that the excitation phase of the bvvsw is different from that of the mssws, which are both in - plane and parallel to the propagation direction. for the first time   it is shown that the observed effect is due to the existence of a nonlinear interaction between the two spin waves.
the ratio between number of fluorescence photons and deposited energy, i.e., the fluorescence yield, is a key calibration parameter determining the energy scale of the @xcite fluorescence telescopes.   a number of experimental values of the absolute fluorescence yields are available in the literature. in this work   we compare the absolute values reported by the above authors. for the most intense fluorescence band at 337  nm  , we normalize all the results to the most accurate experimental data in full agreement with the experimental data. using the same experimental data, we find that the mean value of the total emitted fluorescence intensity along the track of an energetic primary electron is about 1.5  nm in the @xmath0  nm spectral range. however, the emission of the second positive ( 2p ) system of n@xmath2 is much higher than that of the first negative ( 1n ) system at about 15  ev decreasing strongly with an @x math7 dependence. as a consequence, the absorption spectrum of the 2p system shows a very smooth growing behavior at larger energies. on the other hand, the excitation cross section of the 1n system decreases with energy up to about 15
we propose a new model of maxwell s demon, which is autonomous but possesses separated measurement and feedback processes.   the key ingredient in the model is an additional stochastic variable, which plays a role of separating the measurement phase and the feedback phase. on the basis of this factor,   an integral fluctuation theorem ( ift ) with the mutual information can be derived for this model, which has distinct features from the ift obtained for the szilard - type systems. to explain the difference between the two types of autonomous demons, we review the general framework that leads to ift of autonomous and non - autonomous demons in a unified way, on the based of the concept of the partial entropy production.
the physics of systems involving large numbers of interacting agents is currently a thriving field of research.   one of its many appeals lies in the opportunity it offers to apply precise methods and tools of physics to the realm of " soft" science. among them, sports competitions are particularly appealing because of the large amount of data available, their popularity, and the fact that they constitute almost perfectly  isolated  systems. in this work, we study the basic statistical features of game outcomes in major - league baseball using the 163674 regular - season games that have occurred between 1901 and the end of the 2005 season ( 72741 between 190160 and 90933 between 19612005 ). while the record of each team can change significantly from year to year, we find that the _ time average _ win / loss record of the @xmath3-ranked team as a function of rank@xmath4 is strikingly regular during the modern era of major -league baseball, and that the bradley - terry competition model ( bt ) provides an excellent account of the team win / lose records.. another goal of this work is to understand the statistical features for consecutive - game team winning and losing streaks.
among known soft gamma- ray repeaters to date, only sgr 1900 + 14 and sgr 1806 - 20 are the objects for which a secular spin - down of the pulse periods ( 5.16 s and 7.47 s accordingly ) with @xmath2 of order@xmath3s / s was detected and thereby was established that these sgrs are neutron stars with a superstrong magnetic field of order @x Math4 g.   since the end of 1998 we carried out the observations of the sgr1900 + 14 at low frequency ( 111 mhz ) and have detected the periodic pulsed radio emission from this magnetar. in this paper   we report the results of our observations obtained till august 1999.
the relationship between the bare coupling and the cutoff is an essential ingredient in lattice calculations.   usual monte carlo simulations require the knowledge of this relationship far from the critical point, where corrections to asymptotic scaling could become relevant. in this paper   we present a calculation of the first non - universal coefficient of the lattice @xmath0 function in pure yang - mills theory for the three - loop perturbative background of the topological susceptibility in pureyang - millers theory. using a coordinate space method @xcite  , we show that the first two coefficients are scheme - independent ; however, the third coefficient, @x Math12, can be computed by evaluating two - loop diagrams on the lattices provided the corresponding coefficient in the renormalized @x math0 function is known.we give explicit formulae that relate the coefficient@xmath12 to the same coefficient in each of the previous two coefficients. in order to derive the value for @x maths12, we use a two - loops method where firstly the integrands are taylor expanded in powers of the external momenta and then computed term by term with the introduction of an ir regulator
coherent diffraction imaging of single molecules at atomic resolution @xcite is a major goal for the present and forthcoming x - ray free electron lasers ( lcls, sacla, european xfel ).   the continuum approach is an efficient way of modeling damage within large systems, but the continuum methods follow the average single - particle densities, and the recorded diffraction intensities reflect two - particle correlations. in this paper   we analyze this limitation of continuum models and discuss the applicability of continuum model for imaging studies. to study this specific problem we do not need to construct a full ab initio model of radiation damage. instead, we use a simplified molecular dynamics model reproducing the conditions typical for coherent diffraction images that are known from experiments and from theoretical studies of radiation damaged samples. using this model, we derive an approximate formula for signal scattered off an xfels irradiated sample. it is derived from the estimates obtained with single-particle density estimates obtained from the continuum model and then tested against numerical simulations. as a consequence  , we find that the calculated signal intensity can be approximated as an incoherent sum of the intensities scattered at instantaneous snapshots of the system
damped lyman - alpha ( dla ) absorption systems, observed in spectra of quasars, provide a powerful tracer of the chemical history of high redshift galaxies and represent a unique sample for studying the interstellar medium of distant galaxies.   we have carried out a spectroscopic study of a spiral galaxy 1.5@xmath3 away from 3c196 ( q0809 + 483 ) in the hii region of the spectral spectrum of the quasar. to determine the star formation rate ( sfr ) of the galaxy, we measured the luminosity of the hydrogen recombination lines in the optical wavelength range h@x math0 in the absorption line of the host galaxy using emission line imaging. by combining high angular resolution images and high - resolution single - photon resonance ( snr ) spectroscopy  , we show that the sfr of this galaxy is significantly lower than that of the other dlas studied so far : ~1.5 @xmath2 yr@x Math = 0.6 m/yr in the case of the cii@x maths12 absorption lines and ~4.8 yr@Xmath13 absorption lines. however, the sf
tracking active galactic nuclei with austral milliarcsecond interferometry ( tanami ) is a radio vlbi monitoring program of active galactic nucleus ( agn ) jets south of @xmath3 declination.   the observations are performed approximately every two months with the telescopes of the australian long baseline array ( lba ; *???   * ) in combination with telescopes in south africa, antarctica and chile. for the first year of _ fermi_/lat operations, we analyzed the @x Math0-ray emission of the sources in the tanami sample consisting of 65 agn as of 2009 november.    we searched for associations with @x math0-rays from the 1-year catalog under development by the large area telescope ( lat ) team and determined upper limits on the@xmath0-radiation flux for tanami sources without a @x maths0- ray counterpart in this catalog. to obtain a first tentative association of an agn from the sample   a simple comparison of the positions of thetanami sources with that of the #1 lat source in the preliminary version of the first lat catalog turned out to be an
we present a theoretical model to describe the coulomb breakup of a projectile within the framework of the post form distorted wave born approximation ( dwba ) where finite range effects are included, approximately, via a local momentum approximation ( lma ).   we attempt to put constraints on the ground state structure of these nuclei by analyzing almost all the available data on the energy, angular and longitudinal momentum distributions of fragments using various configurations of the projectile ground state. in this paper, we present the application of this theory to the coupling of neutron rich nuclei@xmath0be and @xmath6c on a number of heavy targets.. the results show that the proposed model is able to reproduce the behavior of the breakup reactions induced by the halo nuclei with respect to the core nuclei at high beam energies and has good agreement with the experimental data.
the holographic dark energy ( hde ) is one of the most attractive and active fields in modern cosmology due to the indications of accelerated expansion of the universe through type ia supernovae.   it is derived with the help of entropy - area relation of thermodynamics of black hole horizons in general relativity which is also known as the bekenstein - hawking entropy bound, i.e., @xmath1. here  , we have formulated the scalar field models for hde by using new infrared cutoff ( nhde ) for interacting hde with hubble horizon as an infrared cutoff in non - flat universe. from this model,   the density of hde is calculated as a function of the ricci scalar or generalized form of the rscalar. on the other hand, the stability of the hde model against small perturbations is checked by using the sign of the square of the speed of sound. at the same time, the quantum zero - point energy of a system with size < 1.5   kcal / mol is considered as the limit of the current value of de density.
extremely low mass ( elm ) binaries are the signposts of the type of binaries that are strong gravitational wave sources and possible supernovae progenitors.   we present the discovery of 17 new elm wd binaries from the hypervelocity star ( hvs ) survey of @xcite, including the first degenerate helium - core wd with @xmath5 ( cm s@xmath6 ) surface gravity and the first tidally distorted wd .
we report on the results of the analysis with eclipse mapping techniques @xcite of a set of lightcurves of hs1804 + 67, which allow to follow the evolution of the structure of its accretion disc through the outburst cycle.   the results reveal the formation of a spiral structure at the early stages of the outburst and show how the disc expands until it fills almost all of the primary roche lobe at maximum light, becoming progressively fainter through the decline while the bright spot starts to become more and more perceptible at the outer edge of the disc. at the phase of minimum the disc mostly disappears, leaving only a small bright region around the white dwarf, possibly a boundary layer. in quiescence the disc is asymmetric, with the region along the gas stream trajectory being noticeably brighter than the neighbouring regions.
in this paper we explicitly work out the example of 1/2 supersymmetric bps solutions in a deformed wess - zumino model in 2 dimensions, whose commutative counterpart has been studied long ago by witten and olive in 2 dimensional deformation wz model, as in its 4-dimensional counterpart, a modification proportional to @xmath1 ( with @x math11 as the auxiliary component of the scalar superfield ) arises which breaks all the@xmath5 supercharges explicitly.   but here, unlike in 4- dimension case, also a kinetic part for @x Math11 appears which makes it a dynamical field in contrast to the undeformed theory and it also breaks the whole supersymmetry explicitly. as a result, scalar solitons ( or lumps ) can indeed do exist in 2 spacetime dimensions just as they can in any other dimension, as the deformation of superspace by non - anticommuting odd coordinates in a theory in any dimensions does not violate the conditions of derrick theorem, as it does not bring higher order derivatives into the spacetime formulation of the theory.
the fourth - order quantum diffusion equation @xmath1 is the zero - temperature and zero - field limit of the quantum drift - diffusion model, which describes the evolution of the electron density in a quantum semiconductor device.   it was derived in @xcite from a relaxation - time wigner equation using a chapman - enskog expansion around the quantum equilibrium. for smooth positive solutions,   the equation can be written in a symmetric form for the variable@xmath5 : @x Math6 where here and in the following, we employ the summation convention over repeated indices and the notation @x math7, @x maths8.    this is the multidimensional form of the so - called derrida - lebowitz - speer - spohn ( dlss ) equation, which was derived by means of a scaling limit from the time - discrete toom model and the variable @xMath9 is related to a limit random variable. with the help of the rich mathematical structure of the equation, we have developed numerical approximations which preserve the structure - preserving temporal higher - order numerical properties like positivity preservation, entropy stability, and entropy dissipation estimates.
we are developing tools to determine the ideal aperture size and energy range to use for any source.   these tools take into account the cataloged spectrum of the source of interest, potentially contaminating nearby sources, and emission from the galactic plane. once apertures and energy ranges have been determined, aperture photometry will then be generated for all cataloged gamma - ray binaries.
in a recent paper liang et al. studied experimentally dynamical effects in the coulomb breakup of @xmath0f.   they used first - order perturbation theory to calculate proton breakup via an increase of the effective binding energy of the valence proton treated as if it were a neutron, according to a model that was proposed some time ago by some of us @xcite. here   we report results of such a study for some observables such as parallel momentum distribution and proton angular distributions following breakup. at fixed impact parameter values,   the results show that the reduction of breakup probability for the proton - target is due to the polarization effect of the core - target and to the proion - target coulomomb repulsions.
we consider the anomaly - mediated supersymmetry ( susy ) breaking model @xcite, which is a spontaneously broken global abelian symmetry which is anomalous under qcd. in this model,   the peccei - quinn symmetry is broken and the nambu - goldstone boson ( called " axion " ) couples to the gluon as @xmath7 where @x Math9 is the decay constant of the axion.   we study how axion models can be constructed in the framework of the anomalies - mediated models. in particular, in some class of theaxion model, we emphasize that the axial multiplet changes the prediction of the minimal anomaly - mediating model and that the negative slepton mass problem may be solved. in addition, we show that the resulting superparticle mass spectrum is similar to that of the deflected anomaly mediation@xcite.
electronic filtering of optical signals plays an important role in experimental quantum optics.   the aim of the present paper is to compare the spectral measurements of broadband radiation, based on optical and electronic filtering. using the example of the squeezing spectrum of the atomic resonance fluorescence, we show that the spectral filtering light limits the ability to detect the squeezing to a greater extent than the current filtering light, making the latter preferential for this setup.
we study the diffusion of a new behavior in a complex network where the underlying graph is a random network with given vertex degrees.   we analyze the diffusion in the large population limit for a game where players payoffs depend on the actions taken by their neighbors in the network but not on the specific identities of these neighbors. using a very simple dynamics for the evolution of the play, we show that local interaction can drive the system towards a particular equilibrium in which all players take the same action.
we investigate the evolution of positively curved frw models with a scalar field having the potential which arises in the conformal frame of the @xmath0 theory in vacuum.   we use the methods of the center manifold theory and the normal form theory to study the dynamics of the dynamical systems involved in such models. using these methods we show that the equilibrium corresponding to the de sitter solution of the model is asymptotically unstable, since two of the equations decouple. for an initially expanding universe filled with ordinary matter,   the stability of the equilibrium points is determined by the expansion of the spacetime. for a flat frw space filled with a barotropic fluid in the conformer of the@xmath6 theory we find the same equilibrium points and discuss the physical meaning of these particular solutions.
the gravitino in models with bilinear @xmath4-parity violation is an attractive dark matter ( dm ) candidate since this type of models provides a possibility to reconcile the generation of the baryon asymmetry in the universe via thermal leptogenesis with the constraints on late - decaying particles from big bang nucleosynthesis ( bbn ).   we report on lower limits on the gravitinos lifetime and the corresponding upper limit on the amount of @x Math4-Parity violation that were derived from observations of cosmic - ray antiprotons with the pamela experiment   @xcite. for the decay of the next - to - lightest supersymmetric particle ( nlsp ) in the galactic halo,   the results show that the lifetime limits are in the range of several tens of thousands of gev.    the obtained lifetime limits can be compared to constraints derived from gamma - ray and neutrino observations.
neurons are the fundamental building blocks of information processing by the nervous system of every multicellular animal on earth.   reproducing some, if not all, of the capabilities of a biological neural network using electronic components has always been a goal of research into artificial intelligence. in this work   we propose a type of molecular neuron based on the mechanism of franck - condon blockade and show that it reproduces all the main features of a spiking neuron.
the kondo lattice model of the heavy - fermion material ybrh@xmath12si@x Math12,  @xcite is widely used to describe the quantum phase transition between the non - magnetic metal and the magnetic one.   however, recent experiments of the hall coefficient in this material have provided new intriguing elements that renewed interest in the phase diagram of the klm. in particular, the rapid jump of the Hall coefficient  @xaite is suggestive of a sudden change of the fermi surface topology at, or close to, the spin - density - wave quantum phase transitions between the paramagnetic and the magnetically ordered states.
the second order fermi acceleration is the most promising candidate for the particle acceleration mechanism in the @xcite gamma - ray emission.   we revisit the stochastic acceleration model for the fbs focusing on the effects of the time - dependence and escape from the acceleration regions. by simulating the acceleration and photon emission of the electrons advected away from the shock front with evolving acceleration efficiency  , we show that the emission from the escaped electrons is important.
the symbiotic star ch cygni is a very complex system.   it contains an accreting white dwarf fed from the wind of a red giant and surrounded by an ionized nebula. in the face of this complexity, one way to isolate emission from the accretion region   is to examine rapid ( time scales of minutes to hours ) optical variations. here  , we report the results of our fast photometry of ch cyg between 1997 and 2000. during this period,   the star produced a radio jet after a drop in the optical flux ; in 1998, it entered a high activity state ; and in 1999, the hot source was eclipsed by the red giant. using the 1-meter nickel telescope at lick observatory, we performed high - time - resolution optical differential photometry at@xmath0 and at @xmath2, using the best comparison star, sao 31628, on 14 nights between 1997 or 2000. for each of these phases, we found that the properties of the optical flickering changed, and in combination with the optical spectra, these changes provide information about the accrete disk during jet production, the nature of the high activity states, and the timing of
universality is the amazing phenomenon when the critical behavior arising in different physical systems is characterized by a common set of universal quantities.   all systems belonging to a certain universality class share the same critical exponents, universal amplitude ratios and universal scaling functions. at times,   two system belonging to one universalityclass appear to be entirely disparate at first sight. in this paper   we discuss such a remarkable case, _ viz. that of driven surface diffusion under detailed balance conditions and crystalline solids near their shear instability which are both described by a hamiltonian. using field - theoretic renormalization group ( rg ) methods  , we show that these respectively two and three dimensional systems are described by an idealized hamiltonians. for the latter, we find that the scaling behavior of the system is scale - invariant when an appropriate co - moving coordinate system is used and a certain model parameter vanishes. on the other hand, for the former, we found that the scales of the systems are non - scale - eviscerated when the coordinates of the growth equation are used and the model parameters are neglected.
star formation histories ( sfhs ) of nearby galaxies can be estimated by analysis of their resolved stellar content, as many features present in a color - magnitude diagram ( cmd ) provide evidence of star formation at specific ages.   while significant work has been dedicated to the derivation and implementation of sfh measurement techniques, estimation of uncertainties in these measurements has been given considerably less attention. here  , we evaluate the bootstrap monte carlo technique for estimating the size of random uncertainties in s fh measurements and several alternative approaches. using this approach, we find that the mean uncertainty of the measured sf hs is significantly smaller than that of the simulations performed using the best - fitting synthetic cmds generated through application of stellar evolution models, an observational error model, and other parameters ( e.g., distance, extinction, imf, and unresolved binaries ). when comparing two systems, the relative uncertainties are dominated by random errors.
the cosmological constant problem of quantum field theory is a long - standing problem in theoretical physics.   it arises when one regards the quantum fields as living on the background, and this view runs into a serious problem when one considers the effect the quantumfields should have on spacetime. to address this problem, we argue that if the theory is formulated in a background independent way it allows for the solution of one of the long -standing problems of quantum Field Theory : the cosmologic constant problem. by doing so  , one can formulate the dynamics of a large class of models without recourse to a background structure. notions of distance can then be recovered from the dynamic dynamics of the theory. since general relativity is background - independent, namely, space and time are dynamical degrees of freedom, it is difficult to see how gravity can be included in the search for a quantum theory of gravity.
we investigate the consequences of using completely phase equivalent two - body potentials in three - body calculations based on the adiabatic hyperspherical approach.   the method was suggested and previously tested approximately for two neutrons and a core @xcite. in this report   we carefully follow this prescription using phase equivalent potentials and rigorously derive the short and long - distance behavior of the all - decisive effective radial potentials for cases when one, two or three of the two-body potentials have pauli forbidden states characterized by various quantum numbers. to obtain the results we use a simple @xmath0-wave potential as an analytical example and then show a number of qualitatively different numerical examples.
the origin of cluster - wide magnetic fields is still poorly understood.   two scenarios have received most attention : a ) magnetic fields are initially from the outflows of normal or active galaxies, and such fields can be further amplified by cluster merger and turbulence @xcite ; and b ) very small proto - galactic seed fields are amplified by dynamo processes in clusters, though the exact mechanism for dynamo is still being debated. in this letter, we present self - consistent cosmological magnetic density simulations of galaxy cluster formation with the magnetic field injection from an agn using the newly developed enzo+mhd code to address the question of the origin of magnetic fields in clusters. here  , we explore specifically the scenario that magnetization of the inter - galactic medium ( igm ) by agns initially came from the magnetic fields of an ag n. we also describe the properties of the igm turbulence and demonstrate the existence of dynamo in the icm.
experiments with ultrarelativistic heavy ions at the cern sps which are on the quest for a new state of strongly interacting matter have obtained a wealth of information during the last years.   hydrodynamical models or simple parameterizations have been used as tools to help understanding some of the issues in heavy ion reactions. while even the more complex versions of such models are believed to be crude approximations, it is worthwhile to use them and also the simpler parameterizations to test strongly different scenarios and provide first guidelines on the possible dynamics, if the reaction mechanisms are not too far away from the concept of local thermal equilibrium. in the following   i will review the experimental results on momentum spectra and interferometry that have been applied in applications of these hydrodynamic models and check their implications for the estimates of freeze - out parameters.
quantum computing relies on two - states quantum systems ( qubits ) to store information and quantum gates to process it @xcite.   although other formulations exist, this formulation have dominated the field due to its close analogy with classical binary information processing, among other reasons. in the present paper   we formulate general requirements on control and interaction between systems that represent qubits that are necessary to perform quantum gates via continuous time quantum walks. for systems that have at least one accessible ( higher energy ) auxiliary state in addition to two qubit states, we formulate a class of quantum walk solutions for systems involving one to three qubits. using examples of one-, two-, and three - qubit gates  , we obtain exact analytical solutions for quantum walks on non - symmetric linear chain graphs, with up to five states, and square graphs are obtained.
the intriguing white dwarf  m dwarf eclipsing binary qs vir ( da+m2 - 4 3.6  hr ; formerly known as ec  13471@xmath6 ) was first discovered in the edinburgh - cape blue object survey @xcite.   it has gained considerable recent attention as a potential diagnostic of close binary evolution and angular momentum loss in cataclysmic variables, as well as controversy regarding currently unexplained orbital period variations. here   we review the current state of knowledge about the magnetic activity of qs  vir and discuss the implications of these findings for our understanding of its evolution.
with the growing popularity of real - time data processing in big data environments, there is a pressing need to re - imagine the traditional computing techniques.   we propose a control - flow based intrusion detection technique for big data systems that checks for program level anomalies by analyzing and comparing the control -flow behavior of all processes running inside a big data system using a set of minimum spanning trees ( msts ) extracted from a computer - machine interface ( cfg ). with the proposed technique,   the control-flow of each process running on a data node in the big data cluster is locally analyzed and compared with the control flows of all other processes running on the same node. then, the extracted set of msts are hashed and stored in an array called the _ program signature_ which is encrypted and shared with other replica nodes that run the same program. in the second step, the received encrypted program signature is decrypted and matched with the local version to check for coherence. in this paper, we present a proof of concept of the proposed method for detecting process - level intrusions within big data platforms.
the thermalization process of positronium ( ps ) in mesoporous silica with an interconnected pore network is studied using time of flight ( tof ) spectroscopy.   the effects of the size of the pores on the ps emission energy are investigated and the results are compared with those of a classical model of thermalization of ps in a box ( closed porosity ), which is not expected to be able to reproduce the behavior of ps confined in few nm pores because quantum mechanical effects become relevant. for the first time, we show that the minimum energy of ps emission in vacuum at low temperatures can be determined by measuring the absorption peak of the emitted ps in the x - y components of the pore networks. as a consequence,   it is possible to distinguish between the two types of pores architectures. from the experimental results, we propose a method to measure the ps emissive energy in vacuum based on the theory of bose - einsteinian condensation of ps via phonon scattering.
a two - boson system of sodium or rubidium atoms in an optical trap can be subjected to a one - dimensional double - well potential using coherent laser beams.   the population transfer from the ground state into one of the excited states can be achieved using time - modulated ( i.e pulsed ) electric fields or laser radiation pulses, applied sequentially in a counter intuitive manner. here  , we show that the quantum effects of the radiation, induced by the pulse modulation, on multilevel transitions in a 2-boson system can be studied using floquet theory and the schrdinger equation for the quantum dynamics of this system. as expected, the quantum eigenstates of the system are found to be in the number squeezed state, and the quantum phase space of the eigenstate is similar to that of the classical phase space. at the same time, the excitations of the systems are driven by two sinusoidal electric field pulses applied in sequence, which will be chosen to connect specific undriven energy levels of the System.    the fluence of the pulses is controlled by the frequencies of the fields, and it is shown that the vibrational properties of the spectra of
we argue that it is possible and useful to use the term " complexity science" in a specific and reasonably well defined way.   it is useful because a number of common trends and implications become clear when a phenomenon is classified as part of'complexity science'.the science of complexity emphasises the interactions between components.it stresses that components, most often, are heterogeneous and evolve in time.complexity is concerned with the emergent properties at systems level originating from the underlying multitude of microscopic interactions.we consider here statistical mechanics as a mathematical methodology, which can be applied to many different sciences including economics, population biology and sociology. by systematically applying it to fields outside its traditional range of application in physics, statistical mechanics can be developed further, in addition to simultaneously contributing to the understanding of those fields, such as ecology.
the internet has made it valuable, and that value has naturally led to conflict between contenders for the profits.   many parts of the internet design have avoided such conflict by providing a sufficient supply of valuable resources, and by economic network effects that make one party s holdings even more valuable when others gain similar holdings. in this article,   i discuss the need for the four different sorts of tokens that may be used in a network : handles, addresses, top - level domains, and domain names. with such independence, conflict over handles   should be insignificantly small, and the greater flexibility allowed by independent use of handles and names may allow more effective management of names as well.
the quiescent x - ray properties of neutron star systems are very similar to those of the persistent sources.   the high emission of x - rays from the quiescence states is due to the accretion of matter onto the neutron star surface, and the low emission of radiation below a few kev is caused by the thermal emission of the cooling neutron star. in this study, we investigate the influence of the long term accretion history of the neutron stars on the observed qiescent luminosities. using sensitive imaging instruments, we have been able to measure the time averaged ( over @xmath10 years ) accretion luminosity of the detected systems and obtain estimates of the lifetime of the emitting regions which are in good agreement with the predicted ones obtained from estimates of their accretion histories. during the most recent accretion episode,   both the emitted radii of the emitters and the emitting areas were found to be significantly lower than the expected radii for the system as a whole. at all wavelengths, the emitted radiation is dominated by thermal emission originating from the surface of the cooled neutron star, which can be explained by the residual accretion model. however, the observational data show that the emission of
the proximity effect between a superconductor ( @xmath0 ) and a ferromagnet (@xmath1 ) in a well controlled hybrid structure, where the ferromagnetic slab is replaced by a metal substrate, is studied.   we find that the interaction between the two metal substrates leads to the formation of a new state, @xcite, which is also a fingerprint of the oscillatory behaviour of the pairing amplitude ( cooper pair density ) at the fermi level. for certain values of the exchange field a new superconducting depairing state is realized through first order phase transition from the @x Math3 state and it transforms continuously into the normal state as the strength of the spin exchange field is increased.. this state has a spatially dependent order parameter corresponding to the nonzero center of mass motion of the cooper pairs.    another novel feature of this state is a quasiparticle current flowing in the ground state, which flows parallel to and within a coherence length of the interface., we also find zero energy bound states due to the finite size of the @Xmath1 slab. even though the energy of these states depend on the thickness of the normal
synchronization of neural activity appears in different parts of the mammalian cerebral cortex, and underlies different neural processes in both normal and anomalous brain functions.   it has been suggested that synchronization plays a vital role in information processing in the brain, e.g., processing information from different sensory systems to form a coherent and unified perception of the external world. on the other hand,   synchronization has been detected in pathological conditions such as parkinson s disease and epileptic seizures. understanding the mechanisms of synchronization may be a critical step in elucidating how neural systems work. in this work, we numerically investigated the dynamical mechanism underlying the influence of synaptic efficacy on firing synchronization in hodgkin - huxley ( hh ) neuron networks. to do this, we first studied the dynamics of the response of hh neuron to excitatory synaptic current. when the efficacy of synapse is low, namely, strength is weak and duration is short, the limit cycle is stable to the perturbation of the synaptic current ; however, when synaptic efficacy is high, synaptic current can induce the transition of the neurons from limit cycle to fixed point or transient state which is determined by dynamics of neuron s ion
galaxy clusters are the largest known gravitationally bound systems in the universe.   the detailed analysis of the mass distribution of clusters is thus important in the process of understanding the large scale structure, and the nature of dark matter. to obtain the estimate of the total mass ( including that due to dark matter ) of a galaxy cluster from its x - ray emission it is necessary to make the assumption of hydrostatic equilibrium. here   we use two superb x -ray observatories, chandra and xmm - newton, with excellent angular resolution and exceptional effective area coupled with good spectral resolution to measure the mass of abell 1689, a cluster showing a large discrepancy among various mass determinations. using this method, we find that the mass estimates of the cluster are in agreement with gravitational lensing for clusters with a high concentration of central x - Ray emission ( the so - called " cooling flow " clusters ) but seemingly in disagreement for other, less centrally peaked objects such as @xcite. by contrast, the mass profiles of the galaxies within the cluster appear to be in good agreement with the theoretical predictions of cold dark matter hierarchal clustering.
the most widely accepted model for the structure of an active galactic nucleus ( agn ) consists of a supermassive black hole surrounded by an accretion disc and an axisymmetric distribution of gas and dust.   the broad line region ( blr ) of the torus is the main source of the mid - ir continuum emission in the visible spectrum of an agn, but it can be obscured by the dusty torus depending on the galaxy s orientation. here   we show that the rest - frame @xmath10 luminosity, /@xmath2, as a probe of warm dust emission, correlates with the radio luminosity of the central engine that powers the jets ( e.g. @xcite, @xcites ), a tracer of jet power, and with the light intensity of the narrow line regions ( nlr ), which we assume tracks the underlying continuum emission of the agn. to test this hypothesis, we find that the redshift of the nlr at 178 or 151  mhz correlates with its luminosity with those of the jets at 6c * and 7c *, but not with the luminescence of the blr.
the cosmological constant problem is a great mystery for fundamental physics.   the answer to this question is that we are facing a profound mystery : why is the vacuum energy density of the universe so small?   it is also a mystery why the matter energy density decreases as the universe expands, while the vacuum energies of the two are comparable just at the present time, while their ratio has been tiny in the early universe. here   i try to explain why these two problems are not related, and i discuss the history of the @xmath0-term, which is quite interesting ( this history may also be considered as a warning to over - enthusiastic cosmologists, who believe that the solution of great problems in cosmology lies just around the corner.
quantum state discrimination is one of the most basic yet fundamental tasks in quantum information.   it consists in a protocol that tells in which out of two given states a quantum system was prepared. in this paper   we combine the two concepts above and analyze the optimal performance of a qubit multiple - copy programmable machine when an error rate is allowed. by relaxing the zero error condition slightly  , we show that the resulting scheme provides an important enhancement in performance over the widely used unambiguous scheme.
social media is an increasingly popular communication tool by which people have massive social interactions in cyberspace.   these interactions can have a significant effect beyond cybers space, with real world consequences. here  , we show that twitter, a popular social media, can behave as a network of social sensors, in which twitter users actively sense real - world events and spontaneously mention these events by posting tweets, which immediately spread over user networks in cyber space via chains of retweets ( re - posted tweets ) from other users or followers. using the twitter search api, we compiled a dataset of tweets related to japan s 2013 nippon professional baseball ( npb ) games, including at least one hashtag of npb teams such as @xmath1giants ( yomiuri giants ) and @x math1rakuteneagles ( tohoku rakutenagens golden eagles ), and used a non - negative matrix factorization approach to determine the function of these concurrent bursts of tweets and retwebs in social sensors. for the npb games,   the results showed that the largest number of tweets were related to the game of the yomiori giants team and the second most
the radial distribution functions ( rdfs ) of the various nanoparticles are calculated by assuming that they are continua, for the corrections of the averaged size and the shape effect.   the corrected formulation of the radial distribution function is presented. based on our calculations, the method to estimate the sizes of the parts with ordered and disordered lattice in the particle   is also proposed.
btev is a new experiment being prepared at fnal, usa @xcite.   it is aimed at challenging the standard model explanation of cp - violation, mixing and rare decays in the _   b-_ and _ c-_quark systems. to study final states containing photons, an electromagnetic calorimeter using lead tungstate ( pbwo@xmath3 ) scintillating crystals will be used. for this purpose  , we need to measure the energy resolution with a beam able to span a wide range of electron energies and yet having a low contamination of hadrons and muons.an electron beam in the energy range of 1 to 45  gev which satisfies the above requirements has been commissioned at the u70 accelerator at protvino, russia. since the natural energy spread of the beam is @xmath4  3  % at 27  g ev, we have installed a beam tagging system to determine the energy of each individual electron using a spectrometer magnet and four drift chamber stations.the tag system consists of a 4 meter long spectrometre magnet denoted m14 and four drifting chamber stations. in order to decrease multiple scattering,
the perron - frobenius theorem asserts that a real square matrix with strictly positive entries has a'spectral gap ', i.e. the matrix has a positive simple eigenvalue and all other eigenvalues are strictly smaller in modulus.   it is desirable to obtain a description of a projective contraction and, in particular, a spectral gap condition for complex operators without the above - mentioned restrictions. here   we introduce families of @xmath9-invariant cones in complex banach spaces and a theory for the projective contracting of such cones. using the poincar metric as a ` gauge'on 2-dimensional affine sections of a complex cone, we show that any linear map preserving the cone is a contraction for the metric and the contraction is strict and uniform if the image of the cone has finite projective diameter.
the milky way is a spiral arm of the Milky Way that extends from the border of cassiopeia and camelopardalis to the auriga.   it is characterized by a population of dense dust and molecular clouds, as well as by the presence of young stars and other objects related to star formation. in this review   we will discuss the distribution of these objects in the local spiral arm and their association with the cam ob1 association at a distance of 0.91.0 kpc and with other young objects in its vicinity. 	 we will also discuss the effects of interstellar dust and molecules on the formation of new stars in the region.
a number of phenomenological models describing kaon photoproduction have been proposed in the last decades.   most of them have been performed in the framework of tree - level isobar models, coupled channel approaches, regge model, or quark model @xcite. at present, experimental data are abundant from threshold up to 2.5 gev. however, the exact values of the extracted coupling constants are still not settled. here   we present a new model for the electromagnetic production of kaon based on the su(3 ) symmetry and a number of nucleon resonances that are well known to contribute to the process. by using the regge formalism,   the model is extended to the highest energy range of the threshold energy of interest ( ~2.5 mev ), which is very close to the production threshold ( @xmath7 mev for@xmath8 photoprotozoite ). as a result, the model takes into account all the excited states of the process, including the intermediate states of both the pion and the quark excited states. with the help of this model, we estimate the hadronic and electromagnetic coupling constants of the induced intermediate states
we study the role of long range coulomb interactions in the decay of the superconducting order parameter from a normal metal to a josephson junction array ( jj ) chain.   we take into account phase slips, which have been shown to be important for the unbinding of phase slips in recent experiments@xcite. using a hamiltonian model of jj chain and high-@xmath2 materials, we calculate the average andreev current between the two phases of the order parameter as a function of time and space. by taking into account the screening of the long range coupling between islands, we obtain the phase correlator of the Superconducting Order parameter, which is used to predict the average Andreev currents from a regular metal to an underdoped Jj chain.
we investigate the thermodynamic properties of the @xmath5fe and@xmath6fe isotopes starting from nuclear level densities.   the results show that the thermal properties of both isotopes are strongly correlated with the quenching of pairing correlations, and that the temperature - dependent changes in the heat capacity curve derived from the level density of low - spin states can be interpreted as a signature of a pairing phase transition.
the study of resonances in scattering systems with chaotic classical dynamics is an active field of research.   it has been a very successful approach to gain coarser information on general properties of the resonance distribution in terms of the underlying classical dynamics and geometry, respectively. despite the large progress that has been made in obtaining rigorous results on the distribution of the resonances, there are still many open questions. for example   the upper bound on the exponential growth of the quantum resonances which has been proven in the fractal weyl law @xcite is only conjectured to be sharp and there exists also a conjecture on the improvement of the spectral gap estimates obtained from the previous results. here   we give an overview of the current state of the art in the study of resonance distributions in these systems.
the performance of a quasi - orthogonal space - time block code ( qstbc ) with transmission rate one for four and eight transmit antennas is compared with that of an orthogonaally transmitted channel ( ostbc ) using a mimo antenna system.   the results show that the performance of both schemes is significantly improved with the use of multiple transmit and receive antennas in the presence of rayleigh fading, whereas the effectiveness of the latter depends on the number of receive antennas and the channel rank of the mimo system. by properly choosing the signal constellations as done in  @xcite,   it is possible to improve the ber performance with ml - detection for the codes given in @xcite. the key achievements of this paper are as follows : ( 1 ) the eigenvalues of the resulting equivalent channel are pairwise independent and identical ( i.e., noncentral chi - square distributed with @xmath2 degrees of freedom ) ; ( 2 ) the probability density function of the random mutual information for independent identically distributed channels for two transmit and one receive antennas is obtained from the inverse laplace transform ; ( 3 ) the optimal transmit strategy and the impact of correlation on the outage
concrete computing machines, which perform actual computations in physical time, are not equivalent to turing machines.   the interest in concrete machines comes from their intimate relation with physical time. if computing machines go faster than humans, then one must be confident in their action, as in most cases one can verify the correctness of a result in much less time than is needed to obtain it. even if the confidence one can put in a machine relies on good modelizations of both its physical and logical functioning, how could such a machine perform more than it has been designed for, more than our present theories can modelize?
we investigate the optimal measurement schemes for estimating relative parameters for a rotational degree of freedom given a pair of spin systems.   we prove that any scheme for estimating such relative parameters, performed using only local operations and classical communication ( locc ), can not be optimal in the case where the reference frame ( rf ) is itself quantized ; the ability to perform _ joint _ measurements is necessary to achieve the optimum. by considering the limit in which one of the spins becomes large, we show that the optimal relative measurement for estimating a relative angle can be chosen to be rotationally - invariant, demonstrating that an external reference frame is not required. moreover, we find that the information gain that can be achieved as different aspects of the estimation task are varied, such as the prior over the relative angle or the magnitude of the spinning degrees of freedom, is proportional to the number of spins in the collective tensor representation, and that the need for joint measurements disappears in this limit.. these results contribute to our understanding of how collective degrees offreedom, which are defined with respect to a classical reference frame, can be treated as relative ones between quantized systems.
the bacteria  l. monocytogenes,  s. flexneri,  and  spotted - fever rickettsiae  move through the continual polymerization of actin @xcite in distinctively curved " comet - tails " of filaments behind the motile particles.   the curvature of the tail varies from bacterium to bacterium, and changes over time for individual bacteria ; however, it is not known what determines the bacterial path, and hence the tail curvature. here  , we show that the curve results from the random location of active actin filaments pushing against the bacterium. using video microscopy, we find that the curvatures of the bacterial tail are determined by the number of active filaments at the bacterial surface, and can be used to predict filament lifetime and surface diffusion rates. if filament lifetimes and diffusivities are closely localized to specific bacterial surface proteins, then curvature autocorrelations can be inferred.
abstractwe present the first complete maps of the kinematics and stellar populations of the decoupled core of ngc4365, taken with the wide - field integral - field spectrograph  @xcite.   we show that the core is triaxial, and that the formation of the core involved substantial gaseous dissipation and star formation. at the very centre of the galaxy   there is a blue point source, which is likely to be a point source for the mass of the main galaxy.  in contrast, the core contains a high - metallicity population, with an enhanced  ratio as commonly found in giant ellipticals. using the mg-@xmath15 diagram, we find that the distribution of non - solar abundance ratios is similar to that observed in the morphologically normal galaxies ic1459 and ngc5322, suggesting that the cluster formed from the accretion of material with angular momentum misaligned from that of the major galaxy.
we investigate the effects of extra normal - metal electrodes attached to superconducting electrodes of a sinis cooler on the nonequilibrium distribution of electron energy in a generic sinis structure.   this structure is a nisin@xmath0isin multiple heterostructure which is used to cool electrons in small wires by applying a bias voltage between the two normal electrodes of the device. using a tunneling hamiltonian model based on time - dependent keldysh green function formalism, we show that the effect of the extra n electrodes on theNonequilibrium distributions of the electron energy distribution in all inner islands of the structure is stronger than that in the central n island and that these effects are independent of the chemical potentials of the two superconductor islands.
the recent release of data from the satellite @xcite ( http://www.ncbi.nlm.nih.gov/nci/satellite/xcite/ ) provides a large sample of stars in the solar neighbourhood with distances and full space motions.   the distribution of these stars is broken into several streams : the hyades, sirius, hercules, pleiades, and hercules stream, which are each separated by a distinct radial velocity component. for each stream,   there is little in the way of an underlying smooth component and the entire stellar distribution is broken up into several principal streams. while some of the features are too substantial to have simply arisen from groups of stars that were born with similar kinematics, it is clear that the entire  has been sculptured by dynamical processes.
a new model for the effective two - dimensional dynamics of a vibrated system of spherical particles confined between two parallel plates is proposed.   the model is formulated at the level of particle dynamics, and the methods of non - equilibrium statistical mechanics and kinetic theory developed for inelastic hard spheres and disks can be easily extended and applied to the new kinetics @xcite. as compared with the navier - stokes equations of a normal fluid, the time derivatives of the hydrodynamic fields do not vanish in the homogeneous limit, i.e. there is an homogeneous hydrodynamics. upon studying the linear hydrod dynamic stability of the system and the possible existence of instabilities driving the system to inhomogeneous configurations, it is important to carry out the analysis around the time dependent state defined by the homogenous hydrod dynamical equations, instead of considering linear deviations from the steady state. here  , we show that the solution of the solutions of the first order differential equations of the systems of first order hydrod Dynamic equations of granular media, described by the boltzmann - like equation, allows the identification of the associated transport coefficients, which are given by the values of the macrosc
the density matrix renormalization group ( dmrg ) is a recently developed method for the calculation of the shell model of the low  energy structure of nuclei in the @xmath1shell.   it has been recently applied to a pairing plus quadrupole model of relevance to ultrasmall superconducting grains @xcite, and its convergence properties have been shown to be very similar to those of exact diagonalization. here  , we report here the results of a more thorough investigation of the recent application of the d mrg method to the one - orbit pairing plus quenching model of @Xmath3 + j. the results show that the method can be used to perform reliable large  scale shell - model calculations for the ground state and for low  lying excited states without ever requiring the diagonalization of very large matrices. furthermore, even when the problem was not amenable to exact solution, the method was seen to exhibit rapid exponential convergence.
the study of statistical associations between foreground galaxies and background agns has a long and controversial history.   the results for radio - quiet qsos are confuse and often even contradictory. in this paper   we extend our study to a larger sample ( 21 radiogalaxies ), and perform it in the @xmath3 band. using the data from the 3c catalogue and the literature, we find that the number of apparently foreground galaxies is significantly higher around a sample of 24 radio - loud agn sources with @x Math3 than around a sampling of 21 radio -quiet qso samples. at small scales   there are both positive and negative results, but at large scales there are no detections of positive correlations but evidences of anticorrelations.graphical abstract
we investigate the effect of a small disordered potential on bloch oscillations of bose - einstein condensates in a 1d optical lattice potential.   we show that the inhomogeneity of the disorder potential leads to a significant damping of the centre - of - mass motion, which increases with disorder depth and is quantitatively compared to numerical simulations using the gross - pitaevskii equation ( gpe ). furthermore, the disorder induced broadening of the quasimomentum distribution, which is the underlying mechanism for the damping, reduces the fraction of atoms in the bec.
cataclysmic variables ( cvs ) are close binary systems consisting of a low - mass main - sequence star that fills its roche lobe and a white dwarf.   the evolution of cvs is determined by losses of orbital angular momentum due to radiation of gravitational waves and magnetically coupled stellar wind. in this paper   we investigate the stability of mass exchange against runaway mass loss and its dependence on the donor to accretor mass ratio @xmath1. for stars with deep convective envelope as well as for white dwarfs mass loss results in increase of the radius, while for Stars with radiative envelopes it leads to the shrinkage of the star.
the exploration of complex energy landscapes poses a series of problems of wide interest.   their multi - modal geometry is on one side challenging for optimization algorithms attempting to find the global minimum   @xcite, while on the other side it provides a framework to model slow relaxation dynamics in nature. to disentangle the inherently geometric features of the landscape, we apply a decidedly non - thermal optimization algorithm, called extremal optimization ( eo )  , to explore the energy landscape of a spin glass whose structure has been studied recently with a thermal algorithm @xcite. focusing on the temporal succession of energy values of record magnitude, we present a set of measures which characterizes the difficulty of local searches and the complexity of the geometrical landscape.
the complex dynamics of a fluid of orientable, e.g. rod - like particles is a fundamental example of a soft - matter system driven far away from equilibrium.   the rheological properties of the viscosity of the fluid are already non - linear, implying a non - newtonian behavior of the viscous phase. in the present study   we explore the implications of controlled stress ( as compared to controlled shear rate ) via an extension of the mesoscopic equations for the nematic order parameters for @xmath2 @xcite. in order to fix the (  time - averaged ) shear stress at an externally imposed value, we supplement the five equations of motion for these order parameters by a further differential equation for the shear strain tensor @x Math1, which is governed by a control time,@xmath5.    this control scheme is inspired by the method used in experimental devices : the desired value of the shearing rate is adjusted such that the desired values of the stress and strain are reached at the same time, and the observed shear - banding behavior is studied at different shear rates. within the isotropic high - temperature state, application
we have observed the pulsar vela with a range of australian telescopes.   we have measured the proper motion and parallax of the vela pulsar to an unprecedented accuracy, and have been able to convert these back to its space velocity and position angle with greater precision than previously possible.
the electron transport properties of a semiconductor system based on the two - dimensional electron gas ( 2deg ) are probed with a local perturbation introduced to 2deg by the charge probe at the atomic force microscope tip.   the spatial distribution of the pointer states was extracted by post - treatment of the conductance images as obtained by scanning gate microscopy. in this work   we show that the resolution of the local density of states at the fermi depends on the work point defined by the electron density. for systems with lateral confinement   in the cavity the electron gas deformation can not freely follow the tip, so a local form of the effective potential can only be an approximation of the actual tip potential. for 2deg which is not confined laterally the tip potential is close to lorentzian which for small 2deg - tip distance is isotropic outside the edges of the cavity and of the width near the tip-2deg distance.
the key principle governing the onset of superconductivity in su(n ) gauge theories is the spontaneous breaking of the u(1 ) gauge symmetry via a non - zero vacuum expectation value of a charged field @xcite.   an immediate consequence of this is the generation of a photon mass and, for type ii superconductors, the formation of vortices which confine magnetic flux to narrow tubes as revealed by the ginzburg - landau theory@xcite.the lattice higgs theory, treated as an effective theory, i.e. limited to classical solutions, and considered in the dual sense, provides a model for interpreting simulations of the pure gauge theory that can reveal these important connections.
the evolution of the central regions of galaxies is a complex process, and it is usually difficult to disentangle the relative contributions of the bulge and the disk.   recent studies, benefiting from the high spatial resolution of hst, show that early - type bulges tend to be older, with a small spread in age, similarly to ellipticals, and that the central surface brightness profiles of ellipticals seem to basically separate into two classes : core and power - law cusps. although the dichotomy between these two classes is clear, there are hints for the existence of an intermediate population of galaxies which do not clearly belong to one of the two classes, and are intermediate in terms of absolute magnitude ( rest  2001).this paper is not meant as a thorough survey of our present knowledge of the evolution processes involved in the central structures of galaxies, but more as a short commentary on some of the interesting issues which have been recently discussed in the literature.
we study the trade - off between the rate of description and the reconstruction distortion for a source sequence generated by a source that is to be described succinctly to a reconstructor ( " decoder " ) with access to some side information.   we find that the degree by which the reconstructing terminal utilizes the side information depends on the precision with which the describing terminal can compute the reconstruction sequence. in this paper  , we provide a single - letter characterization of the Trade - Off between the description rate and the distortions at the encoder and decoder sides for discrete memoryless gaussian sources and finite single -letter distortion functions. using a modified wyner - ziv setup where the encoding terminal can influence the decoder s side information via an action - generator, we show that it is possible to improve the trade-off between the two sides by improving the precision of the reconstruction.
the polyakov loop enhanced nambu - jona - lasinio ( pnjl ) model @xcite is a well - studied model for the thermodynamics of strongly interacting matter.   the two major thrusts in recent times have been to estimate various thermodynamic observables using this model, and to make systematic improvements of the model@xcite. in this note   we deal with the improvement of the polyakov Loop model and describe some of its consequences, remaining within the domain of mean field analysis.
the abelian sandpile model ( asm ) is the original model of self - organized criticality, and is one of the simplest and most interesting models of power laws.   the asm is a two - dimensional, conservative, isotropic, two - dimensionally symmetric, stochastic model that evolves stochastically on a lattice of sites, and has been used to investigate the generation of power Laws in a wide range of natural and man - made phenomena.    the asms are robust, and can be used to explain the ubiquity of power law generation in nature. here  , we review the properties of this model, and discuss the relationship between it and the central charge -2 logarithmic conformal field theory ( @xmath10 lcft ), which is the standard model for the same phenomenon.
we have developed a model for proportional elections based on the sznajd model proposed to simulate the process of formation of opinion.   we show that the model is able to reproduce the distribution of the number of votes obtained by different candidates for the 1998 elections in brazil, where the voters vote directly for the candidates and not for the parties. using the results obtained by costa - filho   et al. ( e.g. @xcite ), we also show that this model can be used to model the evolution of social networks.
we study the critical behavior of topological charged black holes in hoava - lifshitz theory of gravity using a canonical framework.   the black hole solution is given in @xcite and the thermodynamic quantities like temperature, entropy, energy etc. are evaluated.    the phase transition of the blackhole solution is studied in terms of the critical exponents of the power laws characterized by a set of static critical Exponents which are found to satisfy certain _ thermodynamic scaling laws _ near the critical point. based on the canonical framework ( i.e. keeping the charge of theBlackhole fixed ), we find that the most important critical exponent for the time scale of the system is depe ndent on @xmath1 where the interaction between the constituent elements is short range. however, for the spatial dimension of the systems, where the space and time themselves are fixed, the critical exponent is found to be depe pn dent on@xmath2. at the same time, the rate constants of the phase transitions are not significantly different from those of the ordinary thermodynamics.
the origin of gamma - ray bursts ( grbs ) remains enigmatic.   the central engine, the photospheric emission, and the particular emission mechanisms are still under debate. here   we show that in about 30% of xrt observations where the first rapid decay after the triggering of the prompt emission is followed by a steep decay phase, the black hole spindown is observed only in the first 10 to 100 seconds of the afterglow emission. for this reason, we propose a new model for the mechanism that powers the burst, the blandford - znajek mechanism ( bz ), which involves the extraction of energy from the rotational energy from a stellar mass black hole. using data from the swift satellite and the bat and xrt instruments aboard the swift spacecraft, we show how the bz mechanism can be used to explain the observed energetic properties of short- and long - duration grbs.
cygnus  x-1 (= hde 226868, v1357 cyg ) is a well - studied x - ray binary.   the binary period, 56, is well - established from optical observations ( e.g. gies & bolton 1982 ) and has also been found in soft and hard x - rays ( 212 kev : zhang, robinson & cui 1996 ; 20100 kev: paciesas et al. 1997 ). here   we report data from the ryle telescope at the mullard radio astronomy observatory, cambridge, uk, during the hard / low state of the 56 period of the source, @xmath0, and from the green bank interferometer at 2.25 and 8.3 ghz. for the first time, we compare the radio data with the soft x -ray data, which are available from the _ rxte all - sky monitor ` quick - look'database covering 212 kevs. using the spectroscopic ephemeris recently derived by tarasov, we show that the modulation at the higher frequencies is stronger at the highest frequencies, and is barely detectable at the lower frequencies.
we study the time dependence of entanglement of initially disentangled few - photon states in the two - mode jaynes - cummings model.   this model closely corresponds to the dynamics of entangling of the photons in the initially pumped cavity with a single atom admitting transitions with different helicities. from the canonical point of view,   the absorption and re - emission of photons with different polarizations is assumed to be completely independent. however, as we will show, due to the complex character of the photon states the interaction with the atom leads to entangling states with different Polarizations with non - trivial time dependent of @xmath0.
we discuss a possible third degenerate regime : dirac neutrino matter consisting primarily of big bang relic neutrinos that have condensed from the primordial and anti - neutrines of the big bang.   we derive the equation of state for the condensation of these particles using the most recent particle data available, which show that they have mass of the order of 1 ev / c@xmath1 ( c : speed of light ) and a mass degeneracy of 6. by deriving the theoretical formula for simple harmonic motion ( shm ) of a galaxy near the center of condensed neutron matter, we show that it undergoes simple harmonic motions with respect to the central galactic mass centroids, which can lead to asymmetric galactic rotation velocity profiles. in this case,   the observed asymmetry is due to the existence of a large number of galaxies embedded within the compacted degenerate neutrine matter object.
weakly interacting massive particles ( wimps ) are a well - motivated class of candidates for dark matter.   they may be directly detected through measuring nuclear recoils in terrestrial detectors produced by their scattering off target nuclei @xcite. here   we designed an experimental configuration : four wimp detectors with cesium iodide ( csi(na ) target are individually placed inside four reactor neutrino detector modules which are used as a neutron veto system. the experimental hall of the configuration is assumed to be located in an underground laboratory with a depth of 910 meter water equivalent ( m.w.e. ), which is similar to the far hall in the daya bay reactor experiment@xcite and the neutron background for this design is estimated using the geant4 @xmath4@xmath5 simulation.    the experimental results show that the detection efficiency of wimp detection can be reached up to about o(@x Math14 ) with csi-doped liquid scintillator ( gd - ls ).
error correcting codes are an important device for communicating information through noisy channels.   a family of error - correcting codes based on an identification with the ever popular ising model from statistical mechanics were proposed by sourlas @xcite, and novel coding methods were examined. in this article   we investigate how the overlap between the original and estimated messages in the first state of the cascading sourlas codes, for which only @xmath4 interactions are considered, are influenced by the employed decoding algorithms when the almeida - thouless ( at ) stability is broken@xcite. using a finite temperature survey propagation algorithm ( sp ) to the first stage of a biased 3-body sourlas code, we find that we can increase the overlap with the original message below the at - transition, which in turn improves the chance of being within the basin of attraction for good decoding once we introduce higher body interactions.
the electrical conductivity of gapped graphene is investigated on the basis of first principles of quantum electrodynamics at nonzero temperature.   the polarization tensor of graphene is derived from the current - current correlation functions of the random phase approximation, the two - dimensional drude model, the quasiclassical approach, the kubo formula, and boltzmann s transport theory. for a pure ( pristine ) graphene having a nonzero mass - gap parameter,   explicit expressions for the polarization Tensor at real frequencies are obtained. in doing so, several novel analytic asymptotic expressions and numerical results ( especially for the imaginary part of conductivity ) have been obtained.
in this paper, we evaluate the upper limit of connected network size above which the network becomes unstable by cascading overload failures and discuss how the maximum stable size can be controlled.   we examine uncorrelated random networks with poisson and power - law degree distributions by employing the model of cascading failures triggered by temporally fluctuating loads proposed by kishore et al. in this paper  , we analyze the stability of networks against cascading overloaded failures and find that the network size can not be increased unboundedly for any given number of nodes. to understand the origin of these results, we use a model of unidirectional networks with stochastic degrees of freedom ( dmfs ) and a poisson model of the degree distribution of the probability of each node to fail due to cascading load fluctuations. using this model, we show that the mean value of the capacity of a network can be reduced by increasing the number of non - interacting random walkers on the network by a factor of 2.5 or more, while maintaining the global connectivity of the network. as a result,   the network can remain stable even at the largest network size.
the emergence of classical dynamical chaos from more profound quantum mechanics is one of the most intriguing problems in physics.   the current consensus is that isolated bounded quantum systems do not show sensitive dependence on initial conditions in the same way as classical systems because their evolution is unitary. here   we show that, even in the absence of any other interaction with the environment, the interaction of the quantum atom - field system with the external atomic degree of freedom provides, under appropriate conditions, the emergence of classic hamiltonian chaos from quantum electrodynamics.
the wrapping of nanoparticles by biomembranes can either occur spontaneously from an interplay of bending and adhesion energies, or can be assisted by the curvature - inducing proteins and protein machineries of cellular membranes.   the cooperative wrapping of prolate or triblock janus particles in membrane tubules provides a route to induce membrane tubulation. for spherical nanoparticles, the stability of these tubules strongly depends on the range of the adhesive particle - membrane interaction that causes the tubulation.in this article, we show that elongated and patchy nanoparticles can induce particle - filled tubules that are highly stable for all ranges of the particle-membrane interaction. here  , we focus on wrapping scenarios in which the characteristic dimensions of the particles are much smaller than the inverse spontaneous curvature and the characteristic length of the membranes where the spontaneous membrane curvature is then negligible, and the bending energy (  ) dominates over the membrane tension.we find that the nanometer - sized particles wrap the membranes in a way that is energetically favorable compared to the individual wrapping of the cells.    the binding of the membrane to the particles results in the formation of membrane tubule - like structures
strongly correlated electrons and heavy fermions display a number of phenomena not understandable within simple fermi - liquid theory of metals.   these unusual effects include dynamical formation of magnetic local moments and magnetic orders, mixed - valence fluctuations, kondo and heavy - fermion behavior, non - fmsl phases and metal - semiconductor transitions. at present   there are two principal approaches for treating electron correlations : ab - initio investigation within the density - functional theory and the local - density approximation taking explicitly into account the coulomb repulsion to equilibrium states within elementary cells ( muffin - tin sphere ) spread over a few interatomic distances. in this paper   we present a new theoretical approach based on many - body perturbation theory with sophisticated renormalizations of one as well as two - particle green functions ( propagators ). in particular we show how the complicated algebra of two-particle multiple scatterings can be simplified to a manageable form by using a single - band theory that can be extended to the multi - band case.
we have proposed an adaptive resolution molecular dynamics scheme ( adress ) that concurrently couples the atomistic and mesoscopic length scales of a generic solvent@xcite.   the system is represented by a flexible polymer chain embedded in a solvent of tetrahedral molecules where the chain monomers are surrounded by solvent with atomistic resolution. when the chain moves around, the sphere of atomistically resolved solvent molecules moves together with the center of mass of the chain. in this way the chain is free to move around, although the explicit resolution sphere is much smaller than the overall simulation volume. as a result  , the solvent molecules in the vicinity of the macromolecule are represented with a sufficiently high level of detail to take the specific interactions between the solvent and the solute into account. for systems of biological relevance, e.g., a protein solvated in water, the solution solvent is represented on a more coarse - grained level. using a dual scale model of a polymer chain in solution   we show that the simulations can be performed at both the time and length scales accessible to simulations that still retain an atomistic level of Detail and the solvent - polymer interactions on longer time and larger length scales.
abstractglobular clusters ( gcs ) are the best examples of a simple stellar population, being defined as an assembly of coeval, initially chemically homogeneous, single stars.   however, recent photometric and spectroscopic studies have shown that each gc is composed of multiple stellar generations, with the coexistence of both first ( fg ) and second generation ( sg ) stars. in this review,   we discuss the current state of knowledge on the formation and evolution of gcs, focusing on the chemical composition of the @xmath4-process elements, like barium, which can be used to address both the formation process and the early evolution mechanisms.
very low frequency ( vlf ) radio waves from a known magnetar sgr j1550@xmath05418 were detected by the south america vlf network ( savnet ) tracking system @xcite on 22 january 2009.   the signal amplitude and phase changes caused by the gamma - ray flares were measured using vlf radio waves recorded from 4:00 to 10:00 ut in brazil, peru, and argentina at the time of the most intense flare ( 6:48 ut ). during the flare,   vlf signals from the earth were reflected at the lower ionosphere and the ground, and propagation within the earth - ionosphere waveguide was observed by npm - ati satellite. since vlf data are sensitive to the condition of the lower ions, they have been used to investigate the physics of the ionosphere..vlf signals were also used to study the ionospheric disturbances caused by high energy photons ( x - rays and gamma - rays ) from extra - solar sources, such as solar flares and giant flares. here  , we report on the first vlf detection of short repeated gamma -ray flares from a magnetar.
class 0 sources are often classified using the spectral energy distribution ( sed ), and class 0 sources have cold spectra that peak in the submillimeter / far - ir band.   hh 24 mms is a class 0 source located @xmath120@xmath0 southwest of the herbig - haro object hh24a in the l1630 cloud in the southern sky. here   we investigate the fragmentation mechanism of this young pre - main - sequence star using high - resolution millimeter observations of the mass and density of the dust emission from hh 25 mms.. the mass of hh 23 mms was found to be very deeply embedded in the dust disk and extended envelope, and the unresolved component of the source has a sed consistent with the presence of a star - disk system surrounded by a collapsing envelope.  also, the x - ray emission from the source is strongly enhanced in the near - ir region, suggesting that it is a highly embedded protostellar system. however, the extent of the fragmentation of the core is not well understood since the nature of the ejection from the core remains unclear. while collapsing cores fragment easily, the relative importance of rotation and turbulence in
the adhesion of microspheres to substrates is a fundamental aspect of microparticle adhesion.   we study the delamination of semi - ordered microsphere monolayers adhered to an aluminum - coated glass substrate using a laser - induced spallation technique, wherein, a pump pulse laser light is used to excite acoustic waves in the substrate to eject the particles from the free surface of the sample and create a tensile pulse that causes delamination near the surface. by monitoring the time - resolved displacements of the surface of a substrate without a monolayer via optical inteferometry, we estimate the adhesive force acting on the monolayered substrate by measuring the out - of - plane surface displacement of the substrate surface at the point of maximum tensile force at the contact between the nanoscale and the microspherically disordered domains of the microstructure. for a pump energy of 36 mj, the effect of the laser - generated acoustic compression pulse on the surface dislodging of the particle - substrate contact is estimated to be ~1.5 times larger than the force acting upon the monobonded monolaying area.    scanning electron microscope images of
regulus ( @xmath1 leo ; hd  87901 ; hr  3982 ; hip  49669 ) is a nearby intermediate mass star of spectral type b7  v.   it is one of a number of nearby b- and a - type stars exhibiting extremely fast rotation, with a projected rotational velocity of @x math3 km  s@xmath4 @xcite. here   we present a summary of the velocities measured in the spectra of regulus from run numbers 1  8, and we find that the star is in fact a low amplitude, single - lined, spectroscopic binary consisting of a pair of k2  v and m4  v pairs at a separation of about 2.5  km.    we also discuss the possible nature of the companion, which is likely to be a low mass donor remnant.
the coulomb interaction between electrons in granular metals and arrays of tunnel junctions is studied using the theory of ambegaokar, eckern and schn ( aes ).   the theoretical framework for the description of these systems is simplified by taking into account only the long range part of the interaction that leads to coulomomb blockade effects. as a result  , we develop a perturbative theory with the macroscopic dimensionless conductance of the granular metal as the small parameter. within this theory,   physical quantities of interest can be calculated at arbitrary temperatures and the diagrammatic analysis is supplemented by the derivation of a @xmath3-model that can be considerably simplified provided one does not take into account weak localization effects.the results show that the aes free energy functional is valid for the described system if the quantum dissipation term is incorporated into the theory.
we study the possibility of having light sterile neutrinos at a scale much below the scale of left - right symmetry.   we show that this can be achieved by fine tuning the yukawa couplings of the left handed neutrino model @xmath2 tev to give sub - ev light neutrines from type i seesaw if the fermions are in the order of tens of mev. using these models, we also show that the lightest neutral particle among them can be a cold dark matter ( cdm ) candidate.
in the current paradigm for the unification of seyfert  2 galaxies, the observed differences are due to significant obscuration along the line of sight to the nucleus in the latter class.   the material responsible for this obscuration lies preferentially in the equatorial plane of the agn, and for this reason it is commonly referred to as the " torus".we present a thorough near - infrared and x - ray study of the nucleus of ngc  3281, which was observed using the irac-1 infrared array camera on the european southern observatory 2.2 m telescope at la silla, chile, and find that the gas - to - dust ratio ( or, more correctly, the ratio of effective hydrogen column density to visual extinction, @xmath2 ) along the lines of sight is more than an order of magnitude greater than the galactic value.    we investigate possible interpretations of this result.
there is a growing interest in the scalar field in the cosmological situations because of its important role played in the inflationary universe scenario@xcite.   there the expansion of the universe is totally governed by the behavior of the Scalar field. in this paper   we would like to make a comment on the effects of nonminimally coupled scalar fields on the expansion behaviour and on the chaotic inflationary scenario. in the de sitter universe,   the effect of the nonminimal coupling constant is similar with that of negativecosmological constant. in some special circumstances   it turns out that such a universe has remarkably rich behavior such that the universe recollapses to a singularity in a finite time. more than that there are situations where the universe show rebouncing behavior before the final collapse. in these situations   most of the time the universe shows an isotropic expansion which is due to the reorientation of the spacetime curvature as well as to the formation of a new vacuum energy of the space - time depending on the spatial curvature constant.
the instantons are non trivial solutions to the euclidean equations of motion which are interpreted as the spontaneous quantum nucleation of a spacetime with some distribution of fields defined on it.   previous studies of instanton solutions possessing either@xmath0, @xcite or @xmath1, invariances have assumed a constant gravitational coupling. in this letter   we treat the gravitational coupling to matter as one such dynamical variable and show that the presence of a varying dilaton field can lead to both singular and non - singular instantons. depending on the parameters of the model, unless we invoke a potential in the dilaton sector the e Euclidean action may become divergent.
the three - dimensional ( 3-d ) fermi surfaces ( fss ) of the transition metal perovskite oxides lanio@xmath0 and @xcite have been studied by angle - integrated photoemission spectroscopy ( pes ).   the x - ray angle - resolved photoemissions of the two dimensional high-@x math2 cuprates and other low dimensional correlated materials have been reported, but there is no report of a fs study of a three - dimensionally correlated oxide. here   we show that the @xmath1 dependence of the imaginary part of the self - energy for a 3.5  0.4 kcal / mol self - energies for the oxygen vacancy controlled metal to antiferromagnetic insulator transition in lanio=xmath21 is due to charge - order rather than orbital ordering as was recently characterized by resonant soft and hard x -ray scattering.
the current generation of imaging atmospheric cherenkov telescopes ( iacts ) have revolutionised the field of very high energy ( vhe ) @xmath1-ray  astronomy.   observational data obtained using the stereoscopic arrays have contributed over 100 new sources to the catalogue of confirmed gev - tev emitters. however, the motivation for astronomers to continue identifying and categorising additional @x math1-rays and source populations remains undiminished. in this work,   we investigate methods for the appropriate statistical treatment of systematic uncertainties affecting iact observational data and their subsequent analysis. by virtue of their ability to capture the temporal variation of the instrumental response to a given experiment, these techniques are able to ameliorate the impact of irreducible systematic effects on the overall error budget and improve the performance of an established technique for source detection originally developed by @xcite.
the ice cube deep core array ( icdc ) is a low energy extension of the icecube detector.   it consists of six densely instrumented strings ( @xmath2  m spacing among optical modules ) located in the deep center region of the Icecube detector plus the seven nearest standard icecube strings. by exploiting the cascade channel  , icdc could firstly provide strong evidence for tau neutrino appearance from oscillations of atmospheric neutrinos, greatly improving previous super - kamiokande ( sk ) results on this evidence  . however, the best fit oscillation parameter values obtained from present data are @xcite :    m^2_21&= & 7.6 10 ^ -5 ev^2 + ^22_23&=& 1 + ^2_12&= and 0.47 with 99% cl allowed regions given by : |m^2 _31|,,,,(2.1 - 3.1 ) 10 ^-3 ev^ 2 + m^two_21+#(7.2 - 8.9 ) 10^{2}+\documentclass{amsidemargin}{amplitude } ( 36 ^ -54^
the lagrangian points of the sun / earth pair @xcite are a feature of newtonian gravity.   they form a configuration rigidly rotating together with the earth, and their stability makes them appropriate to work as basis for a physical reference frame at the scale of the inner solar system. in this paper   we discuss the advantages of exploiting these points for fundamental physics experiments and for the positioning and guidance of spacecraft out of the terrestrial environment.
the radial - velocity variations in the orbit of nine close binary stars observed at the david dunlap observatory have been studied for the first time.   the radial velocities of the binaries are derived from measurements of the spectroscopic orbit parameters : the amplitudes, the center - of - mass velocity, and the time - of primary - eclipse epochs. using a two - dimensional approach borrowed from image processing techniques, we present data for the systems with very weak signatures of binarity in their broadening functions, resulting either from exceptionally weak mg  i @xmath7 triplet lines ( v395  and, section   ) or from the presence of a bright third star in the system ( tu  umi ) which limits the dynamic range in the broadening function. all systems discussed in this paper, except three : hs  aqr, sw  lac, and ks  peg, have been observed by us for radial-velocity variations for theFirst time.
we study the effect of soft - gluon resummation on the transverse - momentum distribution of the incoming partons in prompt - photon production at large @xmath4.   we find that the intrinsic transverse momentum of the outgoing partons can be considered as a function of the number of hard ( rather than soft ) gluons in the hadron, and this is shown to be the case for the high-@xmath8 limit of the inclusive photon cross section.    the results are compared with the recent e706 prompt - photons from the tevatron, where an excess over the qcd prediction has been reported by the cdf collaboration.
the spin - polarized surface currents of a topological insulator can be used to control the magnetic moment of a molecular magnet adsorbed on the surface of a three - dimensional topological Insulator ( ti ) or at the edge of a two - dimensional ti.   the effect is based on the spin - polarization of the surface charge current in the ti, which is triggered by backscattering of electrons moving in opposite directions from the helical edge of the ti. for molecules with a higher spin and for molecular magnets coupled to the two - dimensionally two -dimensional surface of an insulator,   it is possible to manipulate the magnetic moments of the molecules by applying a large enough applied current at the ti surface to flip the localized spin from the " down" state to the " up" state.
we show that the mutation fan of a fan defined naturally by quasi - laminations of marked surfaces equals the rational part of the universal geometric cluster algebra for @xmath0 over  @x Math3 if and only if the surface has a property that we call the curve separation property ( theorem   ).   we show that this property is true for all marked surfaces except once - punctured surfaces without boundary, and that the shear coordinates of allowable curves are universal geometric coefficients when the surface also has a stronger property called the null tangle property.
we report the first measurements of transverse single spin asymmetries for forward jet production by drell - yan ( dy ) dilepton pairs in the 2011 rhic experiment.   the experiments were carried out using modular hadron calorimeters ( hcal ) and beam - beam counter ( bbc ) annuli that are mirror symmetric in @xmath11, where each annulus spans the azimuth in the @x math12 plane with 16 trapezoidal scintillators. at leading order, the hcal response to incident electromagnetic particles ( em ) is averaged over for incident jets, and the reaction energy scale is determined for each event. during the 2011 run,   a large number of events were observed that produced jets, direct photons or virtual photons from polarized proton collisions. among them, we found that the initial state spin - dependent parton distribution function ( pdf ) for the jet was significantly correlated with the orbital angular momentum ( oam ) of the proton, but not with the gluon polarization degrees of freedom. as a result, we propose that the present results are consistent with the existence of a non - zero - spin mechanism for the generation of the jets.
the study of phase transitions under the view of exclusively quantum correlations has hooked the interest of the quantum information community recently.   recent results have shown a narrow connection between entanglement and critical phenomena. here  , we go further in this direction starting from the generic result that, for a bipartite system at thermal equilibrium with a reservoir, there exist two distinct phases, one in which some entanglements are present and another one where quantum correlations completely vanish. to cross this barrier, we give necessary and sufficient conditions to a large class of multipartite Entanglement quantifiers to signal singularities in the ground state energy of the system.    we then exemplify this result with 2-qubit systems subjected to different hamiltonians and curiously it is viewed that, by choosing different entangler quantifiers, one attributes different orders to the phase transition.
the problem of computing the sum of a borel - resummable divergent series expansion has been solved by the direct method by factorial series in the framework of the hyperasymptotic theory @xcite.   this method can be applied to a large class of problems, for instance to the so - called exact bohr - sommerfeld equations which are nowadays quite common in physics. here   we show how the resurgent structure of the borel transform can be described through general tools from resurgent theory, and this allows hyperasy mptotic expansions. using a celebrated test problem, the calculation of the zeros of the airy function @xmath0 in@xcite, we show that the effective resummation of a divergentseries defined implicitly, so that no formal integral is computable, can be done by the same method as the one used in the hyper asymmetric method. however, as we shall see, the resurgents of the series to be resummed are essentially governed by the riemann sheet structure of its borel transformation, which is basically governed by a formal integral which can be derived directly from the problem. with the help of the alien differential calculus
quantum coherence plays a prominent role in the transport properties of mesoscopic systems ; interference between different electron trajectories can lead to interesting effects like weak localization  @xcite and aharonov - bohm oscillations.   inelastic scattering events will destroy phase coherence and as such interference effects will be smeared out. however, a proposal has been put forward some years ago for incorporating these effects phenomenologically within the landauer - bttiker ( lb ) formalism ( which is a single particle theory ), by attaching extra voltage probes to the sample @xcite. nevertheless, only few papers have made use of it because the widely used standard recursive green s function method is unable to calculate the transmission coefficients between the extra voltage probe probes. in this paper   it will be shown how to treat the regime of weak inelastic scattering with a perturbation approach to the original voltage probe model, still keeping the computational effort the same as needed for the standard recursion green s functions.
in ref.   @xcite, two of the authors have developed and explored a very effective approach for constructing numerical black - hole binary initial data. in this paper, we further test the komar - adm mass ansatz for constructing quasi - circular orbits by constructing circular orbits using the effective - potential method. here  , we focus on the spin of the individual black holes in the binary first data set constructed by gourgoulhon et  al. ( j.@xcite. 2015;2:e0099 - 001 - 009 - 0010 ) as well as the inner - most stable circular orbits for both non - spinning and spinning black holes. to achieve these results, we must refine our method for setting the boundary conditions for the calculation of the quasi - local angular momentum of the black holes at the surface of the binary. for the case of corotating black holes,   the choice of boundary conditions is unambiguous, but for non - spins, it is not clear whether the boundaries should be chosen in a way that should be correct in the limit of large separation between the blackhole pairs. finally, we present results related to the inner- and outer - most
we propose an alternative way to create an effective bose - hubbard model for the evolution of polaritons, combined atom - photon excitations, in a coupled array of optical cavities each interacting with an ensemble of atoms.   this is achieved by varying the intensity of the driving laser and hence the strength of the generated kerr nonlinearity that occurs if atoms with a specific level structure, usually considered in the context of electromagnetically induced transparency @xcite, interact with light. using this approach,   we show that strong - correlation phenomena can be observed in a system of photons, which emerges as one of the limits of the polariton excitations.
the influence of the strutural quality of ferro(i)magnetic films ( f ) on the exchange bias of antiferromagnetic films ( af ) has been investigated.   the films were grown at 250@xmath6 substrate temperature to avoid the unwanted interdiffusion of magnesium ions from the substrate into the bilayer@xcite. in the presence of nio and fe@x Math0o@x math1/nio - bilayers, the film thickness of each film decreases with increasing substrate temperature. a stoichiometry of the bilayers was analyzed by x - ray photoelectron spectroscopy ( xps ), while the structural properties were investigated by low energy electron diffraction ( leed ) and @xmath8 x -ray diffraction.the results show that the increase in the thickness of the films is dependent on the crystallinity of the interface between the two films and the grain roughness of the surface of the interfacial layer.  also, the cross - sectional area of the edge of the frayer is affected by the grain roughenerization of the interfaces between the films.
the theory of electromagnetic radiation emitted by a bunch of ultra - relativistic positrons channeling through a periodically deformed crystal ( a crystalline undulator ) is presented.   the essential conditions and limitations which must be fulfilled to make possible the observation of the effect were formulated in an adequate form for the first time. a number of corresponding numerical results were presented to illustrate the developed theory.
in the last years, several generalizations of general relativity have been proposed in order to make 3-dimensional dynamics more alike the realistic @xmath0-gravity.   one of these generalizations is the so called topological massive gravity ( tmg ), which adds to einstein action a chern - simons term free of torsion. in the present work  , we show that it is possible to remove the curvature singularities of topological nature existent in vacuum einstein s general relativity in 3 dimensions by working with a determinantal form of the action. for this purpose, we have found a circular symmetric vacuum solution in three dimensional spacetime without cosmological constant. when the born - infeld parameter@xmath6 tends to infinity, the conical geometry characterizing the elementary solution of the einstein equations in vacuum is replaced by a closed timelike curve, which is consistent with the fact that the angular momentum of the radial coordinate is not only a function of the radius of the origin, but also of the riemann curvature tensor. remarkably, the geodesic incompleteness of the solution is reduced to the same extent as that of
v2491 cyg is a super - soft x - ray source ( sss ) of a white dwarf ( wd ) and a low - mass late type main sequence star.   it was detected by hiroshi kaneda on 2008 april 10.728 at @xmath1=7.7 @xcite and the nova was very fast : @x Math2 ( time needed to decrease in luminosity by 2 mag by 2 min ) in the @x math1 band was 4.6 days and the ejecta velocity reached 4860 km s@xmath3, corresponding to a hydrogen column n(h)=2.5/h = 2.5@x maths5 @Xmath5, assuming a distance of 10.5 kpc from the wd. during the outburst   v2491cyg was observed with _ rosat_,   _ xmm - newton _, and   suzaku  x - rays and extensively monitored with _ swift   x -rays, from the day after the discovery until the pre - outburst flux level, from which the object evolved into a sss. for the first time   the sss
very active, late - type stars show a bluer @xmath0 photometric colour with fainter @x Math1 photometric magnitude ( @xcite ) ; opposite to what one would expect from spotted stars.   the most probable explanation, according to both papers, is a facular component in the photosphere of the active star. here   we investigate whether the faculae explanation can apply to other stars showing the same colour - brightness relation as.
the accurate measurement of cosmological parameters has been a long - standing challenge for cosmologists.   the standard methods for power spectrum estimation work reasonably well for data in a large, contiguous, three - dimensional volume, with homogeneous sampling of the galaxy distribution, and a weighting scheme optimized for the shot - noise dominated errors. however, these methods are not efficient when applied to data in oddly - shaped and/or disjoint volumes, or when the sampling density of galaxies varies greatly over these regions. here   we present a new method for estimating the power spectrum of galaxy clustering based on the karhunen - love ( kl ) eigenmodes of the largest publicly available redshift survey, the las campanas survey ( lc ). using this method, we show that the observed power spectrum can be accurately estimated at the largest wavelength for which an accurate measurement can be obtained by taking into account the effects of both the survey geometry and redshift distortions.
the discovery of a scalar boson with a mass of approximately @xmath8 gev at the large hadron collider ( lhc ) is a spectacular triumph of the standard model ( sm ) @xcite.   the hints of a larger than expected branching fraction for@xmath9, although they have recently weakened, could suggest possible extensions of the scalar sector @xcites. in this paper  , we review the two higgs doublet model ( 2hdm ), a generalization of the so - called dark photon model whose coupling is of the same form as the photon coupling and which can be used to explain the observed astrophysical anomalies such as the @x Math14 gamma - ray from the galactic center or the positron excess observed by atic @xaite and pamela experiments.
extrasolar giant planets ( egps ) are now being discovered at an accelerating pace.   the most studied transiting extrasolar planet, hd209458b, orbits a main sequence g - type star at 0.046 au ( period 3.52 days ) and is the first one for which repeated transits across the stellar disk were observed ( @xmath0 1.6% absorption ; @xcite ). here   we model the spectral absorption features in the mid - infrared ( mir ) due to the most abundant atmospheric molecules during the planet s primary eclipse, i.e., when the planet passes in front of the parent star. using transmission spectroscopy, we show that carbon monoxide ( co ), methane ( ch@xmath8 ) and other photochemical products, such as carbon dioxide ( co@x maths9 ) and acetylene ( c@x Math9 ), are among the most likely to be present in the atmosphere of the transiting egps during their primary eclipse. by combining these results with observations of the second primary eclipse of the planet hd189733b, we find that the absorption features observed in the mir during the transit of this planet are
quantum correlations have a central role in quantum information processing, in quantum foundations, as well as in the physics of strongly correlated systems  @xcite.   the interplay between local and global properties of quantum states is a key aspect in the study of quantum correlations, both from a fundamental perspective and an applicative one. in this work   we study what can be inferred about the quality of the correlations of the global state given information about the two - body reduced states, aiming at answering the question : _ what correlations need to be present globally to explain what we see locally?  in order to answer this question, we provide examples of triples of bipartite reduced states that, albeit separable, are only compatible with genuine tripartite entanglement. by contrast, we find that strictly classical reduced states may still be compatible only with global entangler, and that, at least for qubits, the strict classicality of the two-body correlations makes it impossible to certify genuine multipartite entableries based on the knowledge of the reductions.
the surface amplitudes of @xmath1-mode acoustic oscillations have been known to be significantly smaller within magnetically active regions compared to those in the surrounding quiet sun @xcite.   several theories have been proposed to explain such power suppression. here, we investigate these aspects using our high spatial- and temporal - resolution observations in four different channels obtained simultaneously with the dunn solar telescope ( dst ). for this work,   our main focus is on the suppression of oscillatory power within magnetic regions at low frequencies. as observations progress to higher cadences, it has been observed that at high frequencies (@xmath25 mhz ) the power is in fact enhanced surrounding magnetic regions. at larger heights in the atmosphere, enhanced suppression is found at higher frequencies surrounding active region and quiet - sun magnetic fields. although the exact physical mechanism responsible for these phenomena is not yet clear, currently the most popular theory that explains the observed features at both low and high frequencies is the interaction of acoustic @x Math1- mode oscillations with the embedded magnetic fields, which generates fast and slow magnetoacoustic waves in the magnetic canopy through the process of mode conversion.
experimental research topics require the capability of simulating electron interactions with matter over a wide range - from the nano - scale to the macroscopic one.   the developments described in this paper address the problem of endowing a general purpose, large scale monte carlo system for the first time with the ability to simulate electron impact ionisation down to the scale of a few tens of electronvolts for any target element. for this purpose, models of electron impactionization cross sections suitable to extend geant4 capabilities in the low energy range have been implemented and validated with respect to a large set of experimental measurements : the validation process, which involves experimental data pertinent to more than 50 elements, also addresses the ionization cross section encompassed in the evaluated electron data library ( eedl ) @xcite, which are used in geant 4 low energy electromagnetic package. to the best of the authors knowledge,   this is the first report of extensive experimental benchmarks below 1 kev.
the determination of scattering amplitudes between pairs of mesons is an interesting problem in strong qcd.   it is also a complicated problem, because both annihilation to @xmath15-channel resonances and " nonresonant " scattering are important effects, and it is often difficult to separate the various contributions. by specializing to annihilation - free channels such as i=2@xmath0 and @x Math16, i=3/2 k@x math17, kn and nn, one may study nonres onant scattering in relative isolation.. the determination of resonance parameters, reaction mechanisms, and many other aspects of hadron physics are complicated by the presence of nonresoneant scattering, which is treated as an initial - state and final - state rescattering effect. here   we present a new method for the determination ( using lgt ) of the hadron - hadron scattering amplitude differences between two - meson isobars, based on the calculation of the effective hadronic lagrangian vertex strengths of the quark - gluon interaction.    the results are compared with those of previous work on the analysis of the d and d@x maths19 decays
we propose two hierarchical models for domain adaptation ( da ) and multitask learning ( mtl ), one for da and one for mtl.   we treat the hierarchy nonparametrically, employing kingman s coalescent @xcite. in the da model, we assume that there is a single classifier that " does well" on all domains ; in the mtl model, it is assumed that there are more than two hypotheses to be learned. by using a latent hierarchical structure, we derive an em algorithm that makes use of recently developed efficient inference algorithms for the coalescent, and show the efficacy of our model on several da and mtl problems.
magnetic activity in m dwarfs is directly related to their age.   however, the mechanism that controls this relation is still unknown. here   we use the sloan digital sky survey ( sdss ) to investigate the relationship between magnetic activity and age in a sample of ~1,000 m dwarf clusters from the southern polar region of the solar neighborhood. using a combination of spectroscopic and numerical methods, we find that the activity of the clusters is strongly related to the age of the stars.. the activity - age relation is stronger for the oldest stars than for the youngest stars and is independent of the spectral type of the cluster or the star s mass at the time of observation.    the age - activity relation is best explained by the fact that the number of stars in the cluster is proportional to the size of the magnetic field and the density of the surrounding stars. with the advent of large surveys such as the sdss, it is now possible to obtain a more accurate estimate of the activity lifetimes of the nearby stars and to calibrate the age- and spectral - dependent relation.
the number of dimensions in superstring theory is fixed by the theory.   the theory is only consistent in 10 dimensions. here   we argue that this assumption can be altered and yet we still end up with a theory which is consistent and is lorenz invariant in our 4 space - time dimensions after compactification. to do so we use the light - cone gauge to derive the number of dimensional constraints on the quantisized theory for bosonic string theory and the quaternion gauge to calculate the dimensionality of the quantum gravity of superstrings. using these constraints, we find that the theoretical theory is consistent in all but 4 of the 4 dimensions where the rotation group of the space must be o(d-1,1 ). however the assumption that the uncompacted theory in d dimensions must also be lorenz inv invariant is an assumption which need not necessarily hold true. as a result   it is hard for us to imagine a space of higher than 4 dimensions let alone one with a complex lorenz group structure.
the wetting properties of water on graphene have been extensively studied in the last decade.   however, the physical interactions between graphene and water have remained elusive. here  , we show that the contact angle of water adsorption from water vapor on graphene nanopowders consisting of nanoflakes of different thicknesses is indistinguishable from 180@xmath1 for molecularly thin few layers graphene. this is due to the adhesive interactions from a molecular layer being vanishingly small.
the ginzburg - landau model ( gl ) is a phenomenological model for superfluidity and superconductivity. in its one component order parameter version   it has been used with remarkable success as a statistical mechanics model for the critical phenomena of systems lying in the same universality class as the ising model @xcite. however, in this last situation the @xmath4-expansion, which works very well in the non - gauged version, seems to be insufficient to describe unambiguously the critical properties of the model @xaite.   we have performed a 1-loop calculation of the critical exponents of a gl model with a topological chern - simons ( cs ) term by malbouisson using a fixed dimension approach. due to the presence of a cs term, an intrinsically three dimensional object,   the calculations are performed in @x Math14 and@xmath11, resulting therefore in an uncontrolled approximation since there is no small parameter as @x maths4 or @x math15. only in the large @xMath3 limit   does the scaling allow for a consistent zero cs mass limit. when evaluated at zero external momenta this graph gives zero due to
the laser interferometer gravitational wave observatory ( ligo ) s third scientific run, s3, is now complete, and the data is being analyzed by the ligo scientific collaboration ( lsc ).   the lsc is actively searching for signals from the inspiral of compact binary objects. in this paper   we present a summary of the veto and data quality study results from the s3 data, and state how they will be used in the binary inspiral search.
we show in theorem  that in case the sizes of schools and households are all the same, then epidemics spread more easily in the independent partition model than in the more realistic hierarchical model.   we use branching process approximations to compute this conclusion. for a given number of homes and schools,   the probability that an epidemic will occur if a disease is introduced in a population is estimated by using the expected fraction of the population that is infected throughout the course of the epidemic as the function of the school and household sizes. however, if the size of houses and schools are variable, then the probability of an epidemic is not proportional to the number of schools or households.
there is increasing evidence that supermassive black holes ( smbhs ) exist at the center of all galaxies, and that they are the sources which power active galactic nuclei and quasars.   however, the actual formation process of these objects is still uncertain. here   we discuss the collapse of a supermassive star ( sms ) as one scenario of formation of an smbh. in general relativity,   the onset of radial instability at the mass shedding limit takes place at @xmath11 in the uniformly rotating sms, which is also considered as a critical threshold between formation of a stationary black hole ( bh ) and of a naked singularity. to test this hypothesis, we set up a differentially rotating star, adding radial velocity to induce the collapse, and deplete 99% of the whole pressure to induce its collapse. by depleting the pressure of the star, we find that the criterion of bh formation is @x Math19 when the rest mass is sufficiently larger than the maximum allowed mass on the pressure depleted@xmath1 constant sequence. using numerical simulations, we show that the final state of the collapsing star of @x math13 is a stationary kerr bh.
the problem of packing of spheres plays a major role in the modeling of many physical systems.   recent investigations of such systems have focused on the study of the statistical geometry of the dense sphere packing. in this paper   we propose a simple numerical algorithm to compute void statistics for the packing of shapes other than spheres. unlike a probabilistic algorithm ( monte carlo ),   our algorithm is based on digitization and cell counting. as a proof of concept  , we consider a membrane made up of only circular disks interacting pairwise via the _ lennard - jones _ potential : @xmath0 where,@xmath1 is the distance between the centers of the @x Math2 and @x maths3 disks, @x math4 determines the range of hard core part in the potential and @Xmath5 signifies the depth of the attractive part.we choose the number of disks such that the area occupied by these disks is around @xMath6, which is less than that of the close - packed structure but still large enough to produce some closed voids.    further, we investigate different _ shape anisotropic _ combinations ( dopants ) consisting of # number of circular disks
the superconducting phase qubit ( scpq ) is a macroscopic device with two quantum states decoupled from the environment which can be manufactured and combined with others by conventional techniques.   it consists of a frustrated josephson junction circuit @xcite with two states distinguished by their superconductor phases. in this paper   we propose an experiment to probe the state of such qubits and to determine their decoherence time using the andreev conductance between the ground and a normal wire in the geometry of a fork with the two prongs connecting to two separate islands of the qubit.. the experimental results show that the low-@xmath5 conductance is due to coherent electron diffusion in the normal metal prongs of the " fork " leading to periodic conductance oscillations as a function of the magnetic flux penetrating through the @xmath7 region of the fork. at small bias voltage the quantum phase acquired by the reflected electrons fluctuates and the resulting contribution to the conductivity averages out. at larger voltages   the phase fluctuations become slow compared with the electron tunneling time and the contribution to its conductivity is restored.
we study the behaviour of stochastic billiards in two - dimensional infinite domains ( ` tubes') of the form @xmath0 where @x Math1 and @x math2 are monotone smooth functions.   we consider two types of problem : ( i ) the continuous - time motion of the particle in the tube ; and ( ii ) the discrete - time embedded process obtained by observing the instances of collisions on the boundary.. the embedded process is of interest in its own right, and is also a vital ingredient for the study of the constant - time process. to study the asymptotic phenomena that we study for each process, we consider recurrence or transience, and existence of moments for recurrence times ; and almost - sure bounds for the location of the particles at time@xmath8, as @x maths9. using our results, we obtain criteria for recurrences and transience of our processes which imply that for some cases the particle always has transient dynamics, but can be recurrent for others depending on the reflection distribution. for very shallow tubes such as those with sub - linearly growing widths,   the introduction of random reflections ensures that the process
a parallel dispersive finite - difference time domain ( fdtd ) method for the modeling of three - dimensional ( 3-d ) electromagnetic cloaking structures has been developed and validated.   the method is based on the coordinate transformation technique used in the previously proposed 2-d model of a simplified electromagnetic cloak @xcite, which is able to guide waves to propagate around its central region, rendering the objects placed inside invisible to external electromagnetic radiations. using this method,   a complete set of material parameters of the ideal cloak in spherical coordinate is given by @xmath1, and the distance from a spatial point within the cloak to the center of the cloak is taken as the radial dependent material parameter. under the conventional two - dimensional assumptions, the material parameters can be directly modeled using dispersive material models, for example, the drude model or the full - wave finite element method ( fem ). however, due to the computational complexity of the problem, the methods are not suitable for the analysis of all materials. in this paper, we propose a new method that takes advantage of the dispersive nature of the material model to model the cloaking structure in a parallel manner, and reveal the extraordinary behavior of the
quantization of classical chaotic systems has long been of interest because of the challenges in identifying quantum signatures of systems that, in a classical limit, exhibit chaotic behavior.   we study entanglement by considering a finite multipartite system, whose collective dynamics obey chaotic hamiltonian dynamics in the classical limit. for each qubit,   the linear entropy and the concurrence are used to quantify the degree of entangler between the two subsystems ; for the remaining qubits, the averaged bipartite or pairwise entangling power is used to identify the edge of chaos and quantify the onset of global chaos. as the chaoticity parameter   @xmath0 is increased, the quantum kicked top ( qkt ) undergoes a transition from predominantly regular to predominantly chaotic behavior, which is consistent with the observation that the quantum entropy increases more rapidly for an initial state centered in a chaotic region of the classical phase space than one centered on a fixed point.. furthermore, we show that the pairwise Entangling Power also reveals a dramatic change for a spin coherent state whose mean traverses the edges of chaos on its transit through chaotic and regular regions of the phase space.
the galactic halo of m31 is a large, complex, massive galaxy with a population of intermediate - age stars.   the number ratio, c / m, of carbon - rich ( c ) stars to the oxygen -rich ( m ) stars in all of the halo fields shows a strong correlation with metallicity, and the presence of carbon stars in significant numbers guarantees the existence of substantial populations of intermediate- and late - type stars. here   we review the current understanding of the history of accretion events in the local group and discuss the possible mechanisms by which these events have occurred. using data from the main sequence turnoff measurements of the m31 halo star formation history, we show that the majority of the halos are dominated by carbon stars, with the exception of the dwarf spheroidal cluster of the milky way, which is dominated by oxygen - rich m - stars. despite the fact that there are no carbon stars found in the globular clusters of the small magellanic cloud of the lmc,   this cluster system is known to have a large contingent of heavy metal - poor stars, suggesting that it may have been ingested by a variety of recent mergers.
entanglement is a defining feature of quantum mechanical systems and leads to correlations between sub - systems of a very non - classical nature.   the deeper mysteries of entanglement were quantified by bell in his famous bell s inequalities, which raise testable differences between quantum mechanics and  all _ local realistic theories. since then numerous experimental tests of bell - type inequalities have been made using photons starting with aspect @xcite.. violations, showing agreement with quantum mechanics, of over 200 standard deviations of the original spin of each qubit of information for two subsystems of a quantum mechanical system, including the original state of the atoms, have been reported.    this paper discusses a scheme based on recent results by beige_@xcite which allow to prepare @xmath0 two - level atoms in an arbitrary entangled state by using a leaky optical cavity. during the state preparation no photons are emitted and observing a violation of bell s inequality is the only way to test whether the scheme works with a high precision or not.
the measurement of the cross - section of forward jets in the low - x region at the lhc ( large hadron collider ) is an important test ground for quantum chromodynamics ( qcd ) predictions of the standard model.   the data are obtained from the anti-@xmath6 clustering algorithm @xcite with a distance parameter r = @xmath8 = 0.5. to extend the study of the parton evolution equations,   azimuthal angle differences were also measured. when both jets are widely separated in rapidity ( eg : mueller - navelet jets ), the shape of the proton  proton interaction becomes more complex and the jet   proton interactions become more strongly coupled. as a result, the rate of jet production is faster than expected by the theory and the size of the collision energy is larger than the hard scattering scale given by the jet transverse momentum. this leads to the prediction of new dynamic effects, which are expected to be described by balitsky - fadin - kuraev - lipatov ( bfkl ) evolution and/or @x Math6 factorization.
the self - assembly of ionic nanoparticles from a colloidal suspension onto a glass substrate is an important tool in nanotechnology.   the main goal of our paper is to present a stochastic statistical physics model that encapsulates the essential features of the self - assembling process.    the model is validated by experiments conducted in our lab that show the effect of the concentration of thecolloidal suspension on the nanoparticle coverage of a glass substrates.. the analytical results are compared to the experimental data and to monte carlo computer simulations, and we found excellent agreement between the three methods.
the entropy of the baados - teitelboim - zanelli ( btz ) black hole in the cosmological topologically massive gravity ( tmg ) has been studied and it is found to be satisfied with both the einstein tensor and the cotton tensor derived from the gravitational chern - simons ( gcs ) action.   next, one may consider another kind of black hole solution satisfying the equation of motion totally. for instance, the warped anti - de sitter ( warped ads@xmath0 )   can be considered as a candidate of new vacuum, while the well - known ads@Xmath0 is a vacuum of the btz black hole. once the warped vacuum is defined, then the warped ads#0 black hole can be obtained by coordinate transformations. using the wald s formula, one can see that the entropy receives some corrections : the entropy  (  ) does not satisfy the area law ; specifically, the entropy correction is given by @xmath21 $, where @x Math22 are radial coordinates of inner and outer horizons. in addition, it has been conjectured that the warp factor of the warped ad(s@x
the 16s rrna tag - sequencing approach to identify microbial community members using fragments of dna from the hypervariable regions of the ribosomal 16s gene has become a rapidly expanding field.   although the amount of collected data is growing exponentially, our ability to interpret this data still has important limitations. here  , we combine error - model based denoising and systematic cross - sample comparisons to improve the resolution of 16s data analysis beyond the standard 97%-similarity operational taxonomic units ( otus ) that are commonly used for clustering reads by sequence similarity into operon - based taxonomic unit ( otu ) clusters. in order to achieve this, we have developed a new method that uses a combination of error - models based denobleming and cross - samples comparison to resolve the fine - grained noise in the 16s genome data. with this method, we show that it is possible to assign low - abundance ( sub - abundant ) species to otus using only a small number of samples, and that the resulting otus can be assigned to a single set of bacterial subpopulations without the need for any prior knowledge of the underlying phylogenetic structure of each subpopulation.
celeste ( cherenkov low energy sampling and timing experiment ) was a Cherenkov experiment using the heliostats of the former lectricit de france solar plant in the french pyrenees at the thmis site.   it detected cherenov light from electromagnetic showers produced in the atmosphere by the @xmath0-rays coming from high energy astrophysical sources. during the first one ( between september 1999 and june 2001 ), 40  helistats were used with two types of pointing ( single pointing : all heliastats at 11  km, double pointing : half at 11 or 25  km ), and during the second one (between septmber 2001 and july 2004 ), 53  helisostats pointing at11  km were used ( of which 12 veto heliosteroids aiming wide for proton rejection ).. an analysis improvement has been made on the last data with 53 heliostat taking the crab ( nebula ) data as reference.    the new analysis variable provided a sensitivity of 5.1  @x Math1 on 5.3  h data, whereas the old data analysis gave 2.
the zaklan model is a socio - economic model of social and economic application.   it is based on the equilibrium ising model on square lattices, which has been proposed and studied recently using the nonequilibrium majority - vote model ( mvm ) @xcite. in this paper   we present an analysis of tax evasion dynamics with the zklan model on ans, using mvm for their temporal evolution under different enforcement regimes ; we also show that mvm is capable to control the different levels of the tax evasion analysed in the previous work by zaklans et al.  using ising models.
rayleigh - taylor ( rt ) instability is one of the most fundamental and ubiquitous forms of interfacial instability between fluids with different densities.   it covers a wide range of applications and objects, from microscopic to macroscopic level, such as inertial confinement fusion, astrophysics, atmospheric science, oceanography, combustion, etc. at present, it is still an open subject with many challenging issues, especially those relevant to hydrodynamic non - equilibrium ( hne ) and thermodynamic non - equilibration ( tne ) behaviors in non -ilibrium environments. to investigate those complex non -equilibration manifestations,   a feasible method is to employ the boltzmann equation which describes the evolution of non-equilibrium statistical physical systems. here, we extend the discrete boltzman kinetic method ( dbm ) to the system containing two components with independent specific heat ratios in a force field and study the dynamic process of non - Equilibration rt instability by using the proposed dbm. based on the navier - stokes ( ns ) equations, the proposed model is validated theoretically that it has the capability of simulating ns models describing fluid flows in the hydrodynam limit. in sec.
we study the influence of damping of the molecular motion by emission of phonons into the substrates in a model of one single molecular orbital with strong coulomb repulsion coupled to a dissipative environment.   the dissipation is caused by coupling to phonon modes of the electrodes as well as electromagnetic modes and it is represented by a bath of harmonic oscillators. for this reason, we derive a general formula for the @xmath2-@xmath3 curves using a continuum model for the substrate, and compare our result to a reference model featuring frequency - independent damping and quality factor.
the analysis of polarization power spectra from the cosmic microwave background ( cmb ) is a key step in the study of the origin of gravitational waves.   it is essential to develop powerful and flexible data analysis tools to extract the desired information from the raw data reliably. in this paper   we present a new method for analyzing polarization data using gibbs sampling, extending the sampling steps from temperature to polarization by extending the map making operation from time - ordered maps to block - diagonal covariance matrices. as a result  , we can now analyze planck - sized data using the same approach as previously described for the analysis of the temperature - gradient cross - power spectrum from the wilkinson microwave anisotropy probe ( wmap ) 3-year data . with the exception of the case of uncorrelated noise and symmetric beams,   the sampling process is essentially the same as that for
we address a fundamental question of how the specific energy of phaseonium fuel is scaled with the number of quantum coherent levels.   we show that the scaling law against decoherence and dephasing could be favourable for the performance of quantum carnot engine ( pce ), which is a proposed quantum heat engine for photonic carnot engines. in this paper, we describe multilevel generalization of @xmath0 level atom phaseonial ( nlap ) fuel by exploring how the energy content of the fuel depends on the size of the molecule characterized by@xmath1. as a result  , we can imagine different molecules of nlap for a given atom of unit mass and explore how the particular energy of the atom depends on its coherence phase. next to the phase of coherence,   @x Math1 becomes another control parameter which could favourably contribute to the enhancement of the specific power of the single atom quantum fuel.
the lambda cold dark matter paradigm is consistent with many observable phenomena, but it predicts many more dark - matter halos than are actually seen as dwarf galaxies.   the newly discovered ultra - faint dwarf ( ufd ) galaxies appear to be an extension of the classical dwarf spheroidals ( dsphs ) to lower luminosities ( @xmath1  mag ) and individual stellar metallicities as low as @xmath5. here   we use galaxy formation simulations to test the hypothesis that ufds formed the bulk of their stars prior to the epoch of reionization ( e.g., before the dawn of the universe was fully reionized ) in the milky way. for each of these scenarios, we find that the density of dark matter in the ufd halos is much lower than that in the known dwarf galaxies, suggesting that they were formed during the early stages of star formation. using a new model of galaxy formation, we show that the mass - to - light ratio of the ufs is only a factor of @x Math1  =  1.0, which is sufficient to exclude significant dark matter from the origin of the hal
in this article, we show how luttinger liquids may be obtained from sea - bosons.   this rectifies some serious errors of judgement of previous works @xcite. in addition, we are able to solve for the one - particle properties of various systems highlighted in the abstract. specifically, we can write down a closed formula for the momentum distribution of the wigner crystal mentioned in thestract that does not involve arbitrarily chosen momentum cutoffs and thus is able to provide information about short - wavelength physics as well as the asymptotics.
we discuss the role of weak measurement ( wm ) and quantum measurement reversal ( qmr ) in the protection of entanglement under two - qubit memoryless amplitude damping ( cad ) channel, where the memory effects are characterized by a memory parameter @xmath0 which ranges from 0 to 1.   we show that wm and qmr can effectively suppress decoherence and enhance the entangler transmission under cad channel by choosing proper measurement strength of wm. particularly, for the memoryless and fully memory cases, the maximal achievable entangement approaches to 1. our results provide an active way to suppressDecoherence or enhance the Entanglement transmission under ad channel, which is rather significant in quantum communications.
jordan  brans  dicke ( jbd ) theory is the simplest extended theory of gravity, depending on one additional parameter.   it is used as a laboratory for quantifying how accurately the predictions of general relativity stand up against observational tests. in this paper   we make a comprehensive comparison of predictions of the jbd theory to current observational data, using the wilkinson microwave anisotropy probe ( wmap ) and other cosmic microwave background ( cmb ) data plus the galaxy power spectrum as measured by the two - degree field ( 2df ) galaxy redshift survey. from these data, we obtain complementary constraints from the effect of modified gravity on the structure formation process, which are not competitive with the very stringent solar system bound given above, but complementary in that they apply on a completely different length and time scale. when the universe is dominated by a single fluid, the present value of the cosmological scale factor @xmath18 must correctly reproduce the strength of gravity seen in cavendish - like experiments, which requires @xcite@xmath17 where here and throughout a subscript ` 0'indicates present value.    the results are compared with the expected total intensity and polarization microwave an
we study the local dimension theory of equicontractive, self - similar measures @xmath3 of finite type, whose support is a compact interval and for which the underlying probabilities are regular.   we prove that the set of attainable local dimensions of @x math3 at periodic points in the support of the measure is a closed interval and that theSet of local dimensions at periodic point in the loop class is a dense subset of this interval. when the essential set is the interior of the support ( i.e., the measure has no isolated point in its set of measurable local dimensions ), then the Set of attainability local dimensions can be considered as the union of the local dimensions from the inner and outer parts of the open set condition.
the cosmos survey ( @xcite ; http://www.astro.caltech.edu/cosmos/ ) is a deep multi - band photometric survey that covers an area of about @xmath12 with imaging by space - based telescopes ( hubble, spitzer, galex, xmm, chandra, subaru, vla, eso - vlt, ukirt, noao, cfht, and others ) as well as ground based telescopes. in this paper   we combine publicly available u, b, v, r, i, z, and k cosmos data with proprietary imaging in the humboldt galaxy redshift survey ( hdfs ).   the results show that the cosmological properties of the cosmos survey can be used to probe the evolution of global galaxy properties over a large redshift range from @x math6 to @x Math12.    we find that the observed redshifts of the universe are within the range of 0.0.02 to 0.1 for most of the galaxies studied so far, but also up to a redshift of > 0.5 for some very rare objects such as starsburst galaxies.
the temperature of the ultracold atoms in the optical lattice has to be small in units of typical model parameters.   experimentally it is an open problem to measure this temperature. in a recent work @xcite we found that the temperature in the mott insulating phase of the one - dimensional bose - hubbard model is surprisingly large, namely of the order of the onsite hubbard interaction @xmath0. in an analogous experiment the so - called tonks - girardeau regime ( tg )   was investigated. from this experiment, a rather small temperature of which the hopping parameter  @xmath1 has been deduced. in the present work   we provide a consistent thermodynamic picture of both experiments. for the tg case   the difference in temperature can be understood solely from entropy considerations.in the undoped mott Insulating phase the groundstate is unique and does not carry any entropy.    it is separated from excited states by an energy gap which is determined by the interaction @Xmath0 ; the entropy increases appreciably only at temperatures which are of the Order of the gap. in doped insulators the low - lying states produce a finite
stochastic resonance is a property of level crossing triggered devices or time series sequences.   it is usually assumed that noise in physical systems is gaussian. here  , it is assumed that the noise is more general, i.e. the gaussian noise is replaced by the non - equilibrium, heavy tailed @xmath0-stable noise. for the latter,   the stability index and asymmetry parameter are set to be symmetric and non - asymmetric, respectively. as a function of the scale parameter, the signal - to - noise ratio, spectral power amplification, residence time distribution and probability of a given number of transitions per period of an external driving   are obtained from the analysis of the stochastic resonance induced by the lvy stable noise.
the contribution of the gluon field to the proton spin is investigated using the non - perturbative methods  la heisenberg @xcite.   the main idea of our approach is that flux tubes between quarks in a proton have the angular momentum density coming from colour electric and magnetic fields, which are in the flux tube stretched between two infinitely separated quarks. by considering the quantum superposition of states with different transversal fields in each flux tube   we can calculate the total angular momentum of a Proton.    the results show that the contributions of the green and blue fields to the protons spin are very small.
the pamela satellite ( payload for antimatter exploration and light - nuclei astrophysics ) has produced its first data releases in 2008.   of particular interest has been the positron fraction @xmath13 data, which shows an excess in the 10 -100 gev range with respect to what is expected from secondary cosmic rays, i.e. a fraction diminishing as the energy increases ( secondary electrons and some positrons are produced in the interactions of cosmic ray protons and heavier nuclei ). this result confirms what was earlier called the " heat excess "   @xcite, also observed by ams-01  . it is now clear that the most energetic particles in nature are not only charged particles, but also photons and neutrinos.
restricted boltzmann machines ( rbms ) have become a model of choice for learning unsupervised features for use in deep feed - forward architectures @xcite as well as for modeling complex, high - dimensional distributions@xcite. despite their popularity,   direct learning of these models through maximum likelihood remains problematic.   many learning algorithms have been proposed in the literature to address this issue : stochastic maximum likelihood ( sml ) or persistent contrastive divergence ( pcd ), which relies on a persistent markov chain to sample the negative particles and is run for a small number of steps between consecutive model updates. here  , we show that the choice of @xmath11 can be automated for parallel tempering, both in terms of optimal temperature spacing,as well as the number of chains to simulate. by minimizing the average * return time * of particles under simulation, we find that optimal temperature intervals can be obtained by running the algorithm with a set of chains at different temperatures. using this method, we also show how the algorithm of katzgraber et al. can be adapted to the online gradient setting for use with sml - pt.
the pre - neutron - emission mass distributions of the fission fragments for reaction @xmath0th(n, f ) at intermediate energies up to 60 mev have been calculated by using an empirical fission potential.   the results show that the double - humped and triple - humping pre - neutron - induced mass distributions for reaction@xmath1u(n,f ) gradually change with increasing the incident energies. in this work, we attempt to describe quantitatively both thedouble - humps and triple-humps of the pre - neutron - emission masses for reaction #x Math0th ( n, f)(n = 10, 2 ) at higher neutron energies using five harmonic - oscillator functions. a new model for neutron - induced fission of actinides is proposed based on the theoretical model of the first step of the nuclear fission process, which assumes that a compound nucleus separates into a pair of daughter nuclei in the fissure process. from the model  , we obtain the following parameters : the normalization constant, the mass number of the primary fragment, the position of the peaks of the light and heavy fragments, and the positions of the valleys
the problem of hadron production in the transfragmentation region ( tfr ) in heavy - ion collisions has been studied in the recombination model @xcite, taking into account the regeneration of soft partons and the transverse - momentum aspect of the problem.   the results show that there should be no jet structure associated with the particles detected at any @xmath3 in the forward region.
quantum interference is one of the most intriguing phenomena of quantum mechanics.   several effects in atom - light interaction have been predicted and demonstrated experimentally, which have their origin in quantum interference. in a recent paper   @xcite, a system of two - level atoms strongly driven by a coherent light field and perturbed by collisional noise was analyzed by the quantum - trajectory method. here   we present the detailed analysis of a systems of coherently driven two - levels atoms, when both collisional and phase noises are present. for this purpose,   the master equation describing the system is constructed for the atomic density operator as a set of ordinary differential equations, and the resonance fluorescence spectrum is obtained. based on this  , we carry out the complete quantum - trajectories simulation of the system, which reveals the underlying physical processes in the quantum interference phenomena.
the non - equilibrium green function ( negf ) method coupled with the density functional theory ( dft ) using pseudo - atomic orbitals ( paos ) and pseudopotentials is implemented for the ground state calculation of the electronic transport properties of nano - scale materials such as single molecules,@xcite atomic wires,@xaite carbon based materials,@xficite and thin layers.   the new method is based on a contour integration method which is based upon a continued fraction representation of the fermi - dirac function. to evaluate the equilibrium density matrix within the negf method, we have developed a method for calculating the hartree potential by a combination of the two dimensional fast fourier transform ( fft ) and a finite difference method so that the boundary conditions between the scattering region and leads can be correctly reproduced. in addition, we propose a careful treatment to construct the charge density near the boundaries of the system at equilibrium by treating the equilibrium state of the scattering area under a finite source - drain bias voltage with respect to the self consistent field ( scf ) calculations of the source and drain leads, and the calculated results are incorporated into the Negf calculations through the self energy and the boundary condition
we analyze a system, based on a tunable optical cavity filled with a nonlinear kerr medium, that may be used for the preparation of squeezed coherent - state superpositions.   we obtain a closed expression for an arbitrary initial state of the system and demonstrate that, under certain conditions, squeezed - statesuperpositions can be generated within the cavity.    furthermore, we show that the squeezing degree of the produced states can be easily tuned, a feature that may lead to interesting studies in the field of quantum state engineering.
the financial dynamics is a multiscale phenomenon and the question which of its properties are scale invariant and which are scale characteristic refers to the essence of this phenomenon.   the general solution to this equation reads  @xcite : @xmath4 where the first term represents a standard power - law that is characteristic of continuous scale - invariance with the critical exponent and the second term denotes a periodic function of period one. in the context of the financial dynamics   there exists strong related evidence that at least a large portion of the market dynamics is governed by phenomena analogous to criticality in the statistical physics sense. for the real markets   more and more evidence is collected that the preferred scaling factor, expressed as a ratio of the contraction ratio expressed by the three - cosine, cosine modulus and saw - like functions, is common to all the scales and markets both, in the log - periodically accelerating bubble as well as in thelog - periodically decelerating anti - bubble phases. here   we present a new methodology for the analysis of the global financial dynamics, based on the concept of log - periodicity, which allows to properly map the observed patterns of oscillations in the financial literature.
force - free electrodynamics ( ffe ) has been used to describe the electromagnetic fields of bright crab - like pulsars.   it has been argued that ffe is dissipationless, and that the entire spin - down power is carried by the large - scale poynting flux. in this paper   we show that sfe is well - defined everywhere. for certain initial fields,   sfe reduces to ffe with small dissipative corrections. however, in the regions where the ideal ffe 4-current is space - like, sfe fails in the region where the current is time - like. because of the singularities, we erroneously concluded that sFe reduces to Ffe only in the space - Like current regions, and fails in all the time -Like current regions. on the other hand, we found finite - time singularities for some initial fields in ffe, which are regularized by an arbitrarily small diffusion. using these singularities as a guide  , we calculate the dissipative pulsar magnetosphere and find the microscopic mechanism of the finite conductivity and the radiation counterpart of the dissipation.
we introduce a quasi - deterministic model of the analyser process for in - sequence photon counting experiments.   this model involves an independent stochastic variable in each analyzer, and a deterministic criterion for selecting the polarization eigenchannel in the analyzer. in this model, photons are viewed as field wave packets and trajectory calculations are not involved. using this model  , we show that the law of malus for light polarization measurements can be successfully explained by accumulating the distributions one particle, or particle pair at a time, with no need for a hidden variable model.
very high energy ( vhe ) @xmath0-rays from the galactic center ( gc ) have been detected by the cangaroo, veritas, h.e.s.   @xcite and magic collaborations. in this letter  , we present results on the detection of vhe @x Math0-ray  emissions from the gc using a dataset collected in 2004 with the complete h. e. s.i.d.a.r.t. -2 x - ray observatory. for the first time, we show that the observed @x math0-rares are not due to the formation of new dark matter ( dm ) particles, but to the annihilation of existing dm  particles at the center of a cuspy halo. as a result, we propose a new theory for the origin of the @x maths0-radiative fluxes of very high energy @xMath0- rays from the Gc.
we study the effects of up  down asymmetry in bubble dynamics.   we find that the initial conditions of the cavity determine the bubble shape just before the impact that spawns the worthington jet, a jet of water that shoots upward after such an impact.
the issue of non - gaussianity of the cmb signal has attracted great attention since the release of the wilkinson microwave anisotropy probe ( ) 1-year results ( hereafter wmapi ) refs.   1, 2 and 3. in this paper   we investigate the origin of the peculiarities observed in the low multipoles of the interleukin-6 ( ilc(iii ) ) signal for the k - w band at the synchrotron, free - free, dust emission at the same time as the wmapiii foregrounds. using the de oliveira - costa & tegmark quadrupole data, we show that the spatial distribution of the colloidal temperature anisotropies on the sky is cosmological with respect to the intensity of the background dust emission. by comparing the experimental data with the w map - making algorithm ( mma ) generated by the team, we find that it is most likely due to systematic effects ( such as estimation of the gain factor and foreground separation ) rather than primordial one.
extra spatial dimensions have been widely studied in particle physics since the pioneering works of arkani - hamed, dimopoulos and dvali ( add ) and randall and sundrum ( rs ) ( @xcite ).   the possibility of extra spatial dimensions has been probed in the past colliders but no evidence has been found. in this work   we have investigated the effects of additional spatial dimensions via the process @xmath0 at the large hadron collider ( lhc ). by using a modified version of equivalent photon approximation ( epa ), we show that the process@xmath1 takes part as a subprocess in the main proton - proton collision reaction @x Math5 with quasireal photons which are emitted from one of the proton beams. on the other hand, in the collisions between proton emitting protons and quasires,   both of the incoming protons dissociate into partons while the remaining intact protons remain intact. to test the existence of extra dimensions at the tev scale, we have measured the energy reach and effective luminosity of the processes @x maths0 and @x math3 processes at the lh
active circular depressions are a common feature on the surface of comet 67p / churyumov - gerasimenko ( 67p ).   the origin of these pits has been ascribed to several mechanisms, including impacts, erosion due to insolation, excavation by outbursts, or sinkhole formation resulting from the collapse of a cavity s roof. in this letter  , we examine a series of thermal processes resulting in the local depletion of volatiles, either in the subsurface thus forming cavities, or at the surface leading to an outburst. using a quasi-3d thermal evolution model, we investigate the conditions needed for clathrate destabilization, ice sublimation and amorphous ice crystallization on 67p along its orbit along its orbital evolution.we show that the mechanisms at the origins of active pits on 67c can be multiple, and we place some constraints on the thermo - physical properties required for forming pits at the surfaces of this comet.    we also discuss the effects of different thermal processes possibly affecting the surface and subsurfaces of 67p.
the geometric quantum discord ( gqd ) is an information - theoretic measure of non - classical correlations originally proposed by ollivier and zurek through an entropic ( non - geometric ) approach.   it is known to be sensitive to the choice of distance measures, since it may increase under local operations on the unmeasured subsystem. in this work,   we show that the 1-norm geometric qd can be considered as a good measure of the quantumness of quantum correlations under trace - preserving quantum channels. for bell - diagonal states going through markovian local quantum channels that preserve the bell - diagonality form, we analyze the geometrization of the1-norm gqD as a function of the decoherence probability.    in particular, we provide evidence for the existence of double sudden changes and freezing behavior during its evolution. concerning double suddenly changes, we find that the occurrence of freezing behavior occurs for both the entropical and the schatten 2-norm geometry qd, being interpreted as a sudden transition between classical and quantum decoherent states. moreover, we also consider the dynamical properties of quantum correlation in the xxz quantum spin chain
we study the quantum gravitational bremsstrahlung of a spin-2 quantum gauge theory with massive gravitons in the neighborhood of momentum space.   we find that it is consistent with nature for the very small graviton mass @xmath2 as far as the graviton propagator is concerned, and it is fully lorentz invariant. however, there is a question whether the additional degrees of freedom of the massive graviton give rise to a low strong coupling scale as in the theories ( @xcite ) mentioned above. since the longitudinal graviton states do not belong to the physical hilbert space, we calculate the differential cross - section and the total radiated energy of quantum gravitationalbremsstrahlung in the lowest order of the order of magnitude.
quantum entanglement is a cornerstone of quantum physics and has potential applications in quantum technology, such as quantum information science and quantum metrology.   recently, there has been considerable interest in investigating entanglements in mesoscopic and even macroscopic systems due to the fact that it might provide explicit evidence for quantum phenomena and also might possibly help us to clarify the quantum - to - classical transition, as well as the boundary between classical and quantum worlds. since mechanical oscillators resemble a prototype of classical systems, they are beginning to be important candidates for the investigation of quantum features at both mesoscopic ( e.g., quantum ground state ) and macroscopically ( i.e., stationary entangled state ) scales. here  , we report a scheme to generate quantum entangler between two separated mechanically oscillators in an optomechanical cavity by injecting broad band squeezed vacuum light and laser light into the ring cavity using a kerr - down - conversion crystal consisting of a nonlinear medium and an optical parametric amplifier ( opa ) inside the cavity. through driving the system by the red - detuned laser in the resolved side band limit,   the injected field can be adjusted to the
in this paper we present an experimental test for one of the most debated items in quantum theory, namley the " measurement problem ", within the spontaneous collapse of the wave function model.   the rate of the radiation spontaneously emitted by free electrons, as a consequence of their interaction with the stochastic field, causes an enhancement of the energy expectation value, which, for charged particles, means an emission of electromagnetic radiation ( called spontaneous radiation ) not present in the standard quantum mechanics. using the measured radiation rate obtained for an isolated germanium detector @xcite fu, we obtain an upper limit for the mean collapse frequency @xmath2 based on this effect, using the radiation measured by a system of germanial detectors@xcite.
time in quantum theory is often regarded as a classical parameter labelling the evolution of states, but it is not allowed to fluctuate as position does.   this is because time is considered as a disciplined parameter trained to order events, much as it is used in classical physics. here  , we explore the possibility that true quantum degrees of freedom, those such as fluctuations which completely lack a classical analog, could play a role of or for time. in this way, we will take seriously quantum space - time, not ( just ) as a new and possibly discrete structure but as a fully dynamical quantum entity. more specifically, cosmological models will lead us to an analysis of quantum correlations as quantities changing with a trend. if consistently realized, such a perspective is very different from the traditional ones regarding time : time would be inherently quantum ; it would not exist in a classical world. in semiclassical physics, it remains only as a shadow of the quantum physics that lies beneath.
we investigate the role of doping levels across the laser structure, and, if only possible, to find doping concentrations that would lead to the best opto - electrical parameters, maximizing optical efficiency.   we assume here uniform doping profiles accross laser layers. for simulations, we use sentaurus tcad from synopsys @xcite, which is an advanced commercial computational environment, a collection of tools for performing modeling of electronic devices. in order to find agreement between the calculated results and these observed experimentaly ( the threshold current and the slope of optical power ), we adjust accordingly values of@xmath4 and @xmath5. the results are compared with those of experimentally observed laser parameters. by changing the width of active region ( quantum well ), waveguide width, as well as the waveguide profile by introducing a gradual change of al concentration, we were able to decrease significantly the lasing threshold current, increase the slopeof optical power versus current, and increase optical efficiency of the laser.    the effects are more pronounced at low temperatures.
the detection of circumbinary planets kepler 16 through the multiple system kepler 47 ( @xcite ) has propelled a renewed theoretical effort in explaining how such planets would be assembled in a binary environment.   we investigate planetesimal accretion in the kepler-16 system using fully self - consistent hydrodynamical simulations of the protoplanetary disk and the magnetorotational instability ( mri ), and show that the observed planetesimals are embedded in a highly erosive midplane dominated by a " dead zone " with near - laminar flow driven by magnetohydrodynamically driven turbulence from the magnetic field of the central binary. for the most favorable conditions,   the density of the planetesima is strongly enhanced by gravitational perturbations induced by density fluctuations, and the eccentricity and longitude of pericenter of the region of interest are significantly increased by the development of bulk eccentricities and spirals. however, the magnitude of these effects depends on the details of the hydrodynamic simulation, and may vary depending on the extent of the turbulence. here  , we propose that the acceleration of the global velocity dispersion of the world - sized planetes
we estimate the broadband afterglow emission of short gamma ray bursts ( grbs ) from the hete ii and swift satellites.   we use observational data and some theoretical ideas to estimate the relative magnitudes of the burst duration, fluence and spectral hardness in short and long grbs that have been observed with afterglows. using a multivariate clustering method, we find that the average fluence of short grbs is about 25 kev1 mev, while the average duration of longgrbs with after glows is about 16 s. these results are in good agreement with those of studies of the temporal and spectral properties of short and high - duration grbs. for the short duration grb population,   the peak frequency of the @xmath8 spectrum increases with the bulk lorentz factor of the grb in the external shock model for producing@xmath0-ray emission, but the relationship between the two parameters is complicated by the internal shock model, which shows that the initial jet opening angle of the late - time grb remnant which produces the afterglowing remnant is practically independent of the Lorentz factors of the early grb during the early gabaa phase.
we have derived efficiency estimates for the four quadrants of the vimos spectrum - based optical coherence experiment ( eso ).   the new estimates are based on observations of two spectrophotometric standard stars with the broadest possible slit ( 5@xmath0 ) and the grisms lr - blue ( for u, b, v, and v ) and lr- red ( for r, i, and z ) and were compared with the efficiency estimates provided by thevimos consortium in the past.. the newly derived estimates agree very well with the consortium estimates, except for the b and especially the u - band, where the newly measured transmission is about 20% lower.
hyperfine splitting in the charmonium system is studied using overlap fermions.   we show that hyperfine splitting is very sensitive to the scale of the quark propagator, and that the errors are small all the way up to @xmath7. for heavy quarks,   the effects of the size of the propagator are negligible.
a general and easy to implement bootstrap procedure for functional time series is proposed which generates bootstrap replicates @xmath0 of an observed functional time Series @x Math1 and is applicable to a large class of stationary functional processes.   the procedure avoids the explicit estimation of process operators and exploits some basic properties of the stochastic process of fourier coefficients ( scores ) appearing in the well - known karhunen - love expansion of the functional random variables. under quite general assumptions, the sto chastic process obeys a so - called vector autoregressive representation and this representation plays a key role in developing a bootstrap method for the functional timeseries at hand.. more specifically, to capture the essential driving functional parts of the underlying infinite dimensional process, the first@xmath2 functional principal components are used and the corresponding @x math2-dimensional time series of fouriers is bootstrapped using a @x maths3th order vector autostep autoregression fitted to the vector time series by means of kernel - driven resampling probabilities. in this way, a pseudo - time series with a set of 3d parameters is generated which imitates the temporal dependence of the time series
there is a growing body of work on the dynamical evolution of globular star clusters, in the traditional sense.   this review highlights some of the ways in which @xmath0-body simulations are being used in studying the effects of collisions and stellar evolution on globular cluster dynamics. despite such successes,   it is disappointing that not one of these is a simulation of a globular clustering, as the number of existing globular clusters is likely to be much smaller than is suggested by the particle number alone. while the effect of collisions on the dynamics of point masses can be computed with precision, the influence of collision on the dynamic evolution of stars is very uncertain.    the study of the interaction between stellar and dynamical factors, and the impact of collisions, will require comprehensive simulations of all globularStar clusters within the next few years.
diffuse gas is a major fraction of the baryons in the universe and predominantly exists in the intergalactic medium ( igm ).   diffuse gas around galaxies, i.e., the circumgalaxy medium ( cgm ), is the link between the igm and galaxies. here  , we examine the cgm of galaxies in a cluster environment using data from the virgo galaxy catalog and the sloan digital sky survey. for the majority of the galaxies in this region,   the cGM is strongly influenced by the hotacluster medium ( icm ) and the density of galaxies. however, for the remaining galaxies, the effects of the icm and density are not as strong. to investigate the effect of the environment on these properties, we have used the same spatial and velocity range that we used for the background qso absorption line survey to select 43 absorbers toward 23 background qsos in and around the vir go cluster.    we find that the cgc of the cluster galaxies is strongly affected by the size and density of the ice - filled field. when we consider the cluster and circumcluster environments separately, the results show that the diameter of the Ice - filled fields
the algebraic diagrammatic construction  ( adc ) scheme is a method to approximate the feynman - dyson perturbation of the self - energy of @xcite by means of many - particle techniques similar to those employed for molecules.   the adc scheme is based on the use of the outer valence green s functions  ( ovgfs ) for the orbitals of crystal orbitals and the quantum monte carlo  ( qmc ) method for the fermions. in the present paper, we show that the adsorption of the ovgf orbitals into the self- or energy - dependent self - energies improves the band structure results obtained from density functional theory calculations using the local density approximation  ( lda ) when electron correlations are strong such that in quite some cases the one - electron picture becomes inappropriate.
the lacerta ob1 ( i lacertae ) association is a cluster of 96 members of the gould belt system, including 1 o, 35 b, 46 a, 1 f, 8 k, 3 m - type stars, 1 carbon star and 1 star without spectral information.   the entire lacob1 is centered around ra=22h35 m and decl=@xmath3, and covers the large sky region @xmath4 and @x Math5 @xcite. with a distance less than 400  pc, it ranks among the nearest ob associations in the solar neighborhood, and forms a part of the lindblad ring, which is a giant expanding ring of interstellar matter that is organized into a huge expanding ring, called the lindle blad ring.see research article http://www.biomedcentral.com/1471-7007/1741-2148/9/8/lacerta-ob1.html for a comprehensive reference list of the latest data on the physical properties and dynamical evolution of lacot1.
we propose a renormalization - invariant scheme for the theory of distributional sources of matter on codimension - two branes.   we analyze couplings between bulk fields and brane fields, free to live in the entire six dimensions, and show that the theory is renormalizable. using this approach, we demonstrate that the three and four - point functions of the three - dimensional interactions between a bulk and a brane scalar field are independent of the regularization scheme used to regularize the brane, and that the effects of the coupling terms on the effective theory can be removed by appropriate renormalizations.    we also show that these results are applicable to all possible relevant and marginal couplings.
quantum simulation is an active area of research in which the behavior of complex quantum systems is modeled by simpler, more controllable physical systems.   we describe a system used to manipulate ultracold @xmath3rb atoms trapped in two dimensions using a large area 2d trap which prevents motion in the vertical direction while allowing near - ballistic motion within the plane. at the same time we project customizable light patterns created by an spatial light modulator ( slm ) using intensity modulation. for our experiments we desire an imaging system capable of producing optical structures of comparable size to the atomic de broglie wavelength, which is on the order of 1 @xmath1 m. this will enable a range of experiments, including exotic lattices, and will tie in with our future aim of studying disordered systems in 2d.
the antares neutrino telescope is a multi - detector array in the mediterranean sea, 40  km off the coast of la seyne - sur - mer, france.   it uses a three dimensional array of photodetectors to detect cosmic neutrinos and other ultra - relativistic muons induced by high energy interactions with the atmosphere. at the present time   the detector is equipped with a filter to reduce the optical background rate and to suppress the formation of misreconstructed events that can mimic upward going neutrine induced muons. here   we describe the performance of the detector and the use of monte carlo simulations to investigate the effect of the filter on the elevation angle distribution of the muon track in the detector.
we propose a new method for measuring the weak cosmic shear from the galaxy images using the spatial derivatives of the galaxy surface brightness field ( psf ).   this method is based on the use of fourier transformation to deal with general forms of psf, and is shown to work well on different types of computer - generated mock galaxy images with isotropic gaussian psf. given a high image resolution,   the method can potentially probe the cosmic shears from galaxy substructures, greatly suppressing the shape noise.
electronic transport through an open quantum dot has attracted broad attention due to its potential in the investigation of various bound - state features, @xcite phase coherence,  @xcite and wave function imaging.   by coupling two quantum dots in series or in parallel, a double quantum dot is formed. here   we study the tuning of coupling modes of parallel double open quantum dots ( doqds ) embedded in a quantum wire with a central elongated potential barrier separating the system into upper and lower channels. in addition, an external perpendicular magnetic field is applied to manipulate the electronic cyclotron motion and the coupling between the upper dot ( ud ) and the lower dot ( ld ). using the lippmann - schwinger approach  , we show that the electron probability distribution as well as the electron current flow in the system can be tuned by adjusting the mode mixing between the wire subbands and the dot levels.
a new approach to the computation of hyperbolic tilings is presented.   the approach is based on a planar cellular automaton, which is implemented in the form of a railway model and its implementation in the hyperbolus tiling we use in this paper. with the constraint of using two states only, it is possible to implement the model with the following features : ( 1 ) the train tracks are blank cells marked by appropriate milestones ; ( 2 ) the locomotive is implemented as a single black cell : it has the same colour as the milestones of the tracks ; ( 3 ) the round - about replaces the crossing, a railway structure, by a structure inspired by road traffic ; ( 4 ) the control devices are no more immediate neighbours of the cells where tracks arrive at the point which define a switch ; ( 5 ) the sensors and control devices do not have to be present at the points where the tracks arrive ; ( 6 ) the switches are always located in the same cell ; ( 7 ) the trains are always in one state ; ( 8 ) the signals are always connected to each other via a simple locomotive ; ( 9 ) the circuits are always linked by a * double one * ; ( 10
the optical alignment system ( oasys ) is a real - time monitor of the relative alignment of muon chambers in a muon magnet.   it is a straightness monitor consisting of a fiber optic divergent light source at station one, a convex lens at station two, and a computed tomography ( ccd ) camera at station three. by combining the seven oasy beams for one octant chamber, the translational misalignment of the chambers, as well as rotational and linear temperature expansions, can be measured. to achieve this,   the central axis of the beam is aligned in the plane parallel to the chamber plane with a precision of about 25@xmath0 m. the system is designed to measure the position of the chamber in the time span of minutes anytime during data taking from the phenix experiment at rhic.
type i supernovae ( sne i ) are characterized by the lack of prominent hydrogen lines in the spectra.   most of ordinary sne ib / c, if not all, occur in star - forming galaxies, indicating that they have a massive star origin.. there exist mainly three possible ways for massive stars to become a hydrogen - deficient sn progenitor : mass loss from single stars via stellar winds, binary interactions, and chemically homogeneous evolution with rapid rotation. in this review,   we summarize theoretical results on snib / c progenitors via single and binary evolutionary paths. 	 we emphasize that each case has its own unique prediction that can be in principle well tested by observations.
we present a new method for the analysis of the dynamics of a hamiltonian three degree of freedom ( 3-dof ) galaxy model using poincar maps.   the first step is to reduce the unperturbed system to a two degrees of freedom system and to build up the 4 dimensional map as a stack of 2 dimensional reduced maps. in the second step   we add a perturbation which destroys the rotational symmetry around the @xmath0-axis and then apply a rotation to each copy of the stack structure. by using this method we show that the restricted map on the reduced map can be used to obtain a global panorama of the observed dynamics of the galaxy model.
correlations between time series are fundamental for understanding and interpreting stochastic processes. very often the time between the signals of a series is distributed in an uneven fashion, causing asynchronicity of the compared series.   correlations between asynchronous signals can be of great importance in several areas. when computing the pearson correlation coefficient of two stationary signals we often have to face an important problem : the correlation measure is designed to determine the grade of co - movements of synchronous observations, while the signals are asynchronous. in this paper   we present a method for estimating the asymptotic correlation coefficients for correlated, asynchronous pairs of data based on an appropriate decomposition of the expression for the correlation coefficient for large @xmath0 by using the value of the coefficient for small time window and decay of lagged correlations.the latter can be calculated from the good statistics high resolution data. here   our method is applied to the case of neutron activation analysis.
the generation of continuous variable ( cv ) nonclassical light via the pulse pumped high gain fiber optical parametric amplifiers ( fopas ) using four wave mixing ( fwm ) in fibers is a promising method for quantum communication.   the pulsed twin beams with the intensity difference noise below the shot - noise limit ( snl ) by 3.1 db ( 10.4 db after correction for losses ) were generated by using the high gain fopa with photon number gain of about 16 db. in this paper, we derive a multi - mode quantum theory of the generation of non - degenerate signal and idler beams via the high gains fopa based on the bogoliubov transformation in the analytical form of infinite series. according to the hamiltonian of fwm in fibers,   it is shown that the noise performance of the high Gain fopa highly depends on the joint spectral function ( jsf ) of the fwm. in order to achieve the maximum noise reduction, the jsf needs to be reduced from about 1.1 to 0.5 db ( 2.6 db after corrections for losses).the results show that the jfss of the two modes of the bog
we have made simultaneous 6 cm observations of the a and b  images of 0957 + 561, the first gravitational lens system to be discovered, using a set of vlbi antennas comprising l, k, o, and vlba antennas.   we find that the mass distribution within the lens is constrained by the relative magnification matrix of the core and inner - jet components of each image, and that the time delay between the two images ( @xmath2 ) is approximately 1.5yr.  in contrast, the apparent propagation times from source to observer via two images are estimated to be about 1.4yr.
the topic of parity - time symmetry and its relevance to physical applications on the one hand, as well as its mathematical structure on the other have drawn considerable attention both from the physics and the mathematics communities.   most of this nonlinear activity has been centered around schrdinger type systems, where the original proposal by c. bender and co - workers involved quantum mechanical settings, where this is natural and in addition the hamiltonian hamiltonians were placed chiefly on a similar footing ( i.e., paraxial approximation to the maxwell equations ). however, there have been a few notable exceptions where nonlinear oscillator models ( involving second order differential equations in time ) have been considered, especially in the context of systems consisting of split - ring resonators. here  , we provide a simple, _ prototypical _ nonlinear model of a nonlinear coupled oscillator system for which the linear analog is effectively the one used in the experimental investigations of @xmath0-symmetric dimers in the form of a waveguide dimer, while the nonlinear structure is such that it allows to obtain a detailed numerical and even considerable analytical insights on the phenomenology of such a nonlogistic
the intertwining operator method has been applied to schrdinger equation with position dependent ( effective ) mass to construct first order and chains(iterations ) of first - order darboux transformations.   the second order intertwiner is constructed by taking it as @xmath19-th order differential operator between two hamiltonians with the same effective mass sharing identical spectra upto the zero mode of the supercharge. in this way   one obtains two partner potentials with similar effective mass, but with different spectra. for the first hamiltonian, the intertwining operators are taken as first order differential operators similar to constant mass case, but now they depend on both superpotential and mass function. a detailed analysis has been given about zero mode equations of second order supercharges and possible reduction of 2-susy scheme to first order susy.
the present article presents a model of thermal regulation of an animal.   the model describes heat dissipation from an animal that performs at near to rest metabolism, and is situated in an environment with a temperature that is within the thermo neutral zone ( tnz ) of the animal.the model is not related to the animal as a whole, but rather describes local behaviour of heat transfer and possible mechanisms of heattransfer regulation. for the model to be valid, it is necessary to take into account the fact that any living being lives within a clearly determined range of environmental conditions, where temperature is one of the most important parameters. therefore, the model takes into account this problem from both " ends " of the viable temperature range.
we consider an array of harmonically coupled overdamped anharmonic oscillators subject to additive noise.   the system is governed by the system of langevin equations and exhibits a continuous phase transition with a critical point, where the mean field critical exponent and the stationary probability density are non - symmetric with respect to the control parameter. for weak noise the critical point is determined by the occurrence of a non - trivial solution which yields a value of @xmath19 which is asymptotically correct for strong coupling. for multiplicative noise instead of additive noise also continuous phase transitions are driven by additive noise in the range of 0.1 to 1.5  kcal / mol. for each pair of coordinates the central component of the system undergoes a pitchfork bifurcation if the control parameters change the sign of the equation of motion ( e.g., the number of oscillators ) and the stability of the stationary state is affected by the presence of the critical Point.    we show that the fluctuations at this critical point are non-gaussian and occur at a slower time scale than the noncritical fluctuations. using a self - consistent dynamic mean field theory   we prove that the critical
hd271791 is a massive ( @xmath1 ; przibilla et al.   ( @xcite ) ) extremely high - velocity runaway star with a galactic rest - frame velocity of @x math0, typical of the so - called hypervelocity stars ( hvss ). in this review,   we discuss the possible mechanisms for the origin of hd2717 91 and its peculiar velocity.. first, we consider a proposal by przybilla & colleagues that the star was ejected from the periphery of the galactic disc following the disintegration of a close massive binary system following the supernova ( sn ) explosion as a secondary component of a massive tight binary and that its surface was polluted by the nucleosynthetic products after the primary star exploded in a sn. then, we outline the proposed mechanism for the formation of the hvvs and discuss the implications of the proposed scenario.
we give an entirely new proof of the classification of the tensor ideal localising subcategories of the stable category @xmath4 of finitely generated modules over the group algebra of a finite group from the work of alperin and evens, avrunin and scott, benson, carlson and rickard ( @xcite ).   the proof is based on a new concept of cosupports, which we introduce and study as a generalisation of the theory of @x Math0-points developed by friedlander and the fourth author@xcite.  in this paper we prove that @x math0-cosupport detects projectivity for any finite group scheme defined over a field @x maths5 over a module of homomorphisms, and that it can be used to classify the tenser ideal localizing subc categories of the stable category #2 of all @xMath3-modules over a polynomial ring using methods from commutative algebra.
we study the low - energy properties of the system with a partially filled high landau level@xcite.   we derive the effective interaction between the electrons occupying this level by integrating out all the other degrees of freedom, and find a pseudo - gap with a characteristic width in the tunnelling density of states which confirms the result of the hydrodynamic approach @xcite.the effective hamiltonian enables us to develop a microscopic theory of the thermodynamic and tunnelled densities of states, and a description of spin excitations.
x - ray flares on the weak - line t - tauri star ( wtts ) v  773 tau have been observed many times with the _ einstein _ mission.   the x - ray flare spectra and light curves have been modeled in two ways : as a single heating event in a quasi - statically cooling magnetic loop and as a series of heating events in a coronal active region. here  , we present a new model for the formation of strong white - light flares on @xmath4  ophiuchus, ylw  15, wl  6, and elias  29, which is based on the existence of a magnetosphere / disk coupled to a large - scale magnetized field in the vicinity of the wtss.. the solar - type coronae are characterized by very hot plasma that rises from a quiescent value of 620  mk to a peak value of 50100  mk in minutes to hours and decays on time scales of many hours.    the long - duration flares are a manifestation of continuous reheating events rather than a single flare in a large, low - density loop. at the center of the magnetosphere
we present here the results of a pilot study of near - infrared ( nir ) imaging of three radio - loud quasars ( rlqs ) at z@xmath8 1 using the hubble space telescope ( hst ) and the 4-m class telescope.   the rlq hosts were found to be extremely luminous ellipticals with very high star formation rates, and are close to the brightest cluster galaxies in the local universe. for the radio - quiet quasar ( rqq ) hosts,   however, the distribution of the bulge component is much more variable, with two types of hosts being found : one with a bulge - dominated galaxy and the other with a spheroidal component. by contrast, the rqqs are generally fainter than the rLq hosts, suggesting that the two type of quasar hosts have distinct types of host galaxies, rather than being different only in their level of radio emission.
the m1.0 non - eruptive solar flare occurred on 12 june, 2014, in active region noaa 12087, located approximately 50 degrees south - east from the disk center.   this flare showed an intriguing activity in the vicinity of the polarity inversion line ( pil ) of the line - of - sight magnetic field, which was discussed in a couple of previous works by @xcite. in this work   we present a detailed analysis of the flare energy release in the low solar atmosphere near the pil using various unique observations of the solar atmosphere made by interface region imaging spectrograph ( iris ) and atmospheric imaging assembly ( rhessi ) instruments onboard solar dynamics observatory ( sdo ), together with the helioseismic magnetic imager ( hmi ) instrument onboard new solar telescope ( bbso ). to study the flare processes in the area around the pil, we have used a combination of two different types of multispectral observations : ( 1 ) measurements of the auroral emission from the flare during the first few minutes of its eruption and ( 2 ) measurement of the peak of the flares emission at the end of the eruption. for the first time
mimetic gravity is a new type of modified gravity, in which we replace einstein - hilbert action by another set of geometrical objects like second order invariants or functions of ricci scalar, gauss - bonnet topological invariant and so on.   the main idea behind this new modification of gravity is to propose a conformally invariant, scalar theory of gravity in which scalar degree of freedom does not cause any problem with ghosts. here  , we address noether symmetry issue of such mimetic models. for different types of simulated mimetic gravity,   we have investigated the dynamical behavior of mimetic f ( r ), where @xmath1 is the trace of the energy momentum tensor of matter fields, which is defined by @x math1 and the boundary term is given by@xmath2. using our results, we have shown that the model is physically reasonable, ghost - free and non - minimally coupled, and conformally equivalent to the scalar field theory in einstein frame as well as to the other types of modified gravities proposed in literature.
bacterial motility and pattern formation depend on the production, diffusion and degradation of chemicals that attract or repel bacteria.   chemotaxis is one of the most well - studied examples of bacterial motility, but the mechanisms leading to this behavior are not fully understood. in this review,   we discuss the role of self - induced chemokinesis in the motility of non - acqueous bacteria, such as the bacterium myxococcus xanthus and the eukaryote dictyostelium discoideum ( slime - mould ), which crawl on agar plates and are driven by auto - released fibril trails to aggregate and form multicellular compounds called fruiting bodies. under nutritionally abundant environments or under conditions of high population density, both cellular systems generate repulsive fibrillar trails, leading to the formation of a complex network of molecules which can be used to guide the movement of the cells. here  , we focus on the effects of these molecules on the direction of cell motion and the turning frequency of the drosophila melanogaster, a slow - moving rod - like organism which crawls on an agar plate. using a
a scripted dialogue is a dialogue which is performed by two or more agents on the basis of a description of that dialogue.   the plan of this paper is to first motivate why the study of scripted dialogues is interesting and useful, whilst also pointing out the limitations and complications of scripted dialogue. in addition  , we present a number of strategies for the automated generation of scripteddialogue.
self - interstitials are common in silicon and they are expected to react with impurities to form defect complexes.   hydrogen is a very common impurity in semiconductors whose roles in silicon include passivating surfaces and defects, and hydrogen - silicon complexes have been detected in experiments. here   we report the results of calculations on the @xmath7 family of self-interstitials based on the split-@xmath4 self - interstitium defect.    the results show that the most stable structure is the hexagonal interstitial with two hydrogen atoms bonded to one silicon atom and one hydrogen atom bonded to a neighbouring silicon atom, i.e., the highest energy structure. for the tetrahedral interstitial,   the second nearest neighbour silicon atom to the hydrogen has a dangling bond, whereas van de walle and neugebauer s lowest energy structure does not contain dangling bonds.
we report the results of two target of opportunity ( too ) observations of grb970402  by the _ beppo_sax  gamma ray burst monitor ( grbm ) and the ulysses satellite.   the first observation was performed on april 3.280 ut, @xmath19 hours after the burst trigger. in the wfc unit 1,   two sources are detected at a high statistical significance : one is near the center of the wide field camera error circle and the other is west of it. for the second observation we find that 1sax j1450.16920  lies on the eastern edge of a diffuse quasi - circular emission region with an x - ray emission in the second too. to our knowledge, this is the first report of a gamma - ray  and x - rays  afterglow from a gamma rayburst detected by a single satellite.
the interpretation of astrophysical spectra depends heavily upon the availability of collisional rate coefficients for the rotational excitation of molecules in collisions with h@xmath3.   the theoretical calculation of such data is extremely time consuming, involving the computation of a potential energy surface for the system in question, followed by extensive scattering calculations. even for those molecules for which such calculations have been carried out, the available data are often limited to collisionally - excited collisions involving a relatively small set of low - lying states. here, i have explored the use of an artificial neural network ( ann ) to extrapolate a set of rate coefficients obtained from quasi - classical trajectory calculations for transitions among the lowest 45 rotational states of water that are characterized by an energy, @xmath4, and rotational quantum numbers @x Math5, @ xmath6 and @x math7 that describe the total angular momentum and its projection onto the principal axes of the molecule.. the performance of the ann in reproducing a known set of collisionals is discussed.
the phase - field method is a powerful tool for the simulation of solidification microstructures, due to its capability to simulate complex time - dependent and three - dimensional morphologies with relatively simple numerical codes @xcite.   the general principle of this method is to describe a multi - phase system by a set of phase fields which take constant values in each of the bulk phases and vary smoothly through interfaces of a characteristic thickness @xmath0.. however, the equations of motion for the phase fields and their coupling to the local thermodynamic state variables ( temperature, density, composition etc. ) can be obtained by taking a variational derivative of a free energy functional that depends on the phase field, the temperature, and the concentration. here  , we present a model of the solidification of a pure substance using the two - phase approach, in which the interface is treated as a mixture of two phases, each of which retains its bulk properties even inside the interface. under this approach,   all equilibrium quantities and transport coefficients are interpolated between the coexisting phases with smooth functions of the phasefields that can be freely chosen from the equation of motion, and both the equilibrium and kinetic properties of the interfaces
high redshift galaxy clusters provide important laboratories for the study of structure formation and galaxy evolution.   we report the discovery of a high redshift cluster at @xmath8 in the xmm cluster survey ( xcs : *????   * ) and the measurement of its x - ray temperature. at@xmath11,   xmmxcs  j2215.9 - 1738 is the most distant cluster with spectroscopic redshift confirmation to date.
in a number of semiconductor nanosystems at low enough temperatures the ballistic transport properties are dominated by a single resonance. in the fano regime   strongly asymmetric conductance peaks as well as anti - resonances are observed @xcite which result from a coherent interaction of the resonance with a nonresonant background.   it is known that in real experiments one has to add to this coherent conductance a noncoherent conductance background resulting from independent transmission channels. here   we analyze the pulse transmission properties in the presence of a fano resonance. assuming a simple gaussian incident pulse and the validity of eq. (  ) fano - type resonances in the stationary conductance @xxcite we obtain a first analytical description to cover the pulses in the entire Fano resonance regime. using the landauer - bttiker formalism we show that in a pulse transmission experiment, one can distinguish between a resonant and a nonreonant conductancebackground making it possible to determine the parameters @xmath8 and @x Math6 uniquely.. however, at typical confinement lengths in the order of tens of nanometers we find typical times to resolve the needed shape
the solar dynamics observatory ( sdo ) takes full - disk images of the sun in 3 uv - visible and 7 euv channels with a resolution of 0@xmath2.6 pixel@x Math0.   the channels of 211 , 193 , 171 , 304 , 1600  and 1700  are used to detect the plasm outflows along the coronal loops rooted at the edge of ar noaa 11504, which were observed about from 18:00 ut to 23:00ut on july 1, 2014 using the atmospheric imaging assembly and the helioseismic and magnetic imager ( hmi ) @xcite instruments onboard the sdo. during the observation period,   plasma outflows are observed in these channels with velocities ranging from tens to hundreds km s@x math0, and they are thought to originate from the cancellation of small scale mixed magnetic fields at the boundary of the main active region by the reconnection events occurring at the foot points of coronal loop.
the method of maximum relative entropy ( which we abbreviate as me ) is developed to generate optimal approximations for the probability distribution functions ( pdfs ) of simple classical fluids.   the general formalism is developed by using the use of relative entropy as the unique and natural criterion to select the preferred approximation, which is labeled by some parameters. a suitably weighed average over the whole family of trial distributions with the optimal weight provides an optimal approximation. in the second part of the paper   we demonstrate the proposed formalism by applying it to simple classical liquids, a well studied field in the past barkerhenderson76-@xcite. to approximate the behavior of simple fluids we chose trial distributions that describe hard spheres that describe soft spheres @xcite-@xcite. from these distributions we choose the preferred value of the hard - sphere diameter and then marginalize over the variational parameters to obtain the optimal approximation with a suitable weighting. at high temperatures   this leads to significant improvements over the standard variational method. when tested on a lennard - jones model for argon with molecular dynamics simulation data we find that the me predictions for thermodynamic variables and for the radial distribution function
the occurence of a transition between hadronic phase and ( deconfined ) quark phase in dense matter is an unsettled issue. from the experimental side,   observing the formation of a quark - gluon plasma is one of the main objectives of cern - sps and rhic experiments.   this state of matter is also expected to take place in the interior of neutron stars, due to the high pressures typical of the stellar core. however, the phase transition in energetic heavy - ion experiments typically involves low densities and high temperatures, whereas high density cold matter constitutes the inside of stable neutron stars. here  , we explore the characteristics and the model dependence of the quarks - hadron phase transition for weakly isospin - asymmetric nuclear matter within the mit bag model. using the energy density of quark matter as a starting point, we discuss possible values of the bag parameter @xmath4 and a simple parametrization for its density dependence, based on the condition that the energy densities of the Quark phase and the Hadronic phase are equal at the transition. by taking into account the observed value of @x Math4, we find that the model
m51 is one of the most famous galaxies in the sky, known as the " whirlpool galaxy " because of its close proximity to its companion ngc  5195.   it is also a very interesting target for studying its population of young massive star clusters ( ymcs ), which are abundant in interacting and merger galaxies like e.g. the " antennae " ngc 4038/4039. here   we study the ymc population in m51 using archive hst / wfpc2 images obtained by the lick 3 meter shane telescope at mount hamilton, california on mar 13  14, 2000 with the prime focus camera ( pfcam ). from these images,   the specific @xmath1-band luminosity of the m51 cluster system is derived and compared with other galaxies, including the milky way and the light - emitting diode galaxy ( lmc ), and the area - normalized star formation rate of the whole cluster is calculated. among the many clusters studied, only a few are found to be large enough to support a significant number of stars, suggesting that they are likely to have been formed from different types of star formation.
quantum theory is a new type of probability theory.   its predecessor, classical probability theory, is very intuitive and can be developed almost by pure thought alone employing only some very basic intuitions about the nature of the physical world. in a recent paper   i have shown that the basic structure of quantum theory for finite and countably infinite dimensional hilbert spaces follows from a set of five reasonable axioms ( @xcite ) which are consistent with both conventional probability theory and quantum theory. here   we discuss the main ideas referring interested readers to the main paper@xcite.
abstracth@xmath0o is a measure of the mass of hydrogen in the atmosphere of a white dwarf star.   it is currently used to measure the bulk composition of extrasolar asteroids and minor planets. here   we discuss the use of white dwarfs as a tool for studying h@x Math0o within extrasolar planetary systems. while the interstellar medium has usually been assumed to be the source of the hydrogen accreted onto helium white dwarf atmospheres, recent studies have found that the atmospheric hydrogen content of these stars increases with the cooling age of the star, suggesting ongoing hydrogen accretion during the white dwarf phase of evolution. however, the importance of this process is uncertain since the mean free path between interstellar atoms is greater than the typical accretion radius and the fluid approximation fails. instead, alternative models for the accretion of hydrogen should be considered including the aftereffects of the destruction of a parent body with internal ice and the effects of the host star s high luminosity asymptotic giant branch evolution.
we present a quantum model of photon - pair emission in a nonlinear, one - dimensional photonic - band - gap structure, based upon a perturbative solution of the schrdinger equation.   this model extends those developed for bulk nonlinear materials in @xcite and is compatible with models based on methods of classical nonlinear optics ( multiple - scale spatial and temporal expansion methods ) with a specific kind of stochastic averaging concerning emitted spectra. at the single - photon level,   the model describes the spontaneous character of the process of parametric down - conversion of a quantum field in a layered medium. as a result  , the model can be used to predict the behavior of physical quantities characterizing a photon pair, both for cw and pulsed pumping regimes.
the hologram is the interference fringe of the recording wave and the object wave, and therefore, for retrieving the hologram image with sufficient viewing angle the spatial frequency gets to the extent of the wavelength of the light field.   the holographic display can reconstruct the image to the display size, but the viewing angle of the reconstructed image is still limited because of the high spatial frequency of the fringe pattern. in this research, we find how to enlarge the viewing zone of the reconstruction image optically by varying the incidence angle of a plane wave illuminating the holograms in other direction than that used in the recording process. first, for the fresnel and fourier holograms we investigate the possibility of the viewing angles change by varying an incidence angle at which the illuminating plane wave generates high - order diffracted beams emanating to the shifted position of the recovered image, which can make the viewing area with another perspective of the image.    next, in the sampled hologram with pixel structure the method of extending the viewing zones angle by collecting high - Order diffracted beam is proposed.. finally, we carry out the numerical analysis for the sampled overlapped hologram showing high - ordered diffraction beams with various viewing zones.
the finite temperature behavior of free sodium clusters in the size range of @xmath1=39 - 55 is investigated by density - functional molecular dynamics ( dfmd ) simulations.   the results show that the shape of the heat capacity curve is size sensitive, e.g. it is not easy to discern any melting peaks below@xmaths1=25 for the small clusters. however, the simulation data available at rather coarse sizes above @x maths1=40 already show size - sensitive feature. as expected most of the atoms in these clusters lie on the surface and a discernible core develops after about @x math4=15 - 16. from the obtained equilibrium geometries,   two distinct evolutionary trends are observed : the first one is that of symmetric partially icosahedron core and the second one is of complete icosahedral core.
chaotic systems have several significant features favorable to secure communications, such as aperiodicity, sensitivity to initial condition and parameters, and random - like behavior.   however, during the last decade, many pitfalls and drawbacks of cryptosystems based on chaos synchronization have been found. among them are : low security due to easy reconstruction of chaotic dynamics @xcite, slow performance speed due to analytical floating - point computation, and weak resistance against channel noise due to large bit error propagation caused by finite chaos synchronization time. in this paper   we propose to use a one - way coupled chaotic map system to construct a cryptosynthesized system with optimal overall properties. for example, we use spatiotemporal chaos to fully apply and develop the advantages of chaotic cryptography, and on the other hand we incorporate some simple algebraic operations in the conventional cryptographic methods to overcome the disadvantages of analytical chaotic computations. with the combinative applications of chaotic and conventional methods our system has optimal cryptographic properties much better than the separative application of chaotic- and conventional - based methods known so far.we design an experiment set with embedded cpus and use this set to practice duplex voice secure communications in realistic wired public switched telephone
the electronic structure and magnetic properties of a series of ti@xmath15 ( @xmath7=fe, co, ni, @x Math8=al, ga, in ) heusler alloys with the hg@x math0cuti - type structure have been investigated by density functional calculations.   the structures of these compounds are characterized by the scalar relativistic version of the full - potential local - orbital ( fplo ) minimum - basis band - structure method using the generalized gradient approximation ( gga ) for exchange - correlation ( xc ) potentials and the perdew - burke - ernzerhof 96 of the generalization of generalized gradient approximations ( ggas ) for transfer - correlation potentials ( xcs ).. the slater - pauling ( sp ) behavior of the total moments is studied by the differential scanning calorimetry ( dsc ) and the bulk and the effect of lattice constant are analyzed by the energy - dispersive x - ray diffraction ( edx ). to study the half - metallicity of the compounds, we have determined that the most commonly used crystal structure of the proposed heus
the conflict between quantum mechanics ( qm ) and local hidden - variable theories ( lhvts ) is more apparent in tri- or multipartite quantum systems which was analysed by greenberger, horne and zeilinger ( ghz ) state for single neutrons @xcite where one external degree of freedom ( path states in the interferometer ) is entangled with two internal degrees of freedom   ( spin and energy ) leading to a violation of a mermin - like inequality.   this violation confirms the impossibility of noncontextual hidden variable theory ( nchvt ) from quantum contextuality.
short gamma - ray bursts ( grbs ) are short bursts with a measured redshift, isotropic burst energy and rest - frame spectral peak energy @xmath17 mev.   they have been observed in both early- and late - type galaxies with older stellar population ages, and at systematically larger radial offsets from their host galaxies than long grbs..we propose in this article the existence of two families of short grbs, both originating from binary neutron star ( ns ) mergers : the difference between these two families depends on whether the total mass of the merged core is smaller or larger than@xmath18. for the first family, we assume that the coalescence of the merging nss leads to a massive ns as the merged cores. for each family,   the presence of the bh allows us to address the grb nature within the fireshell model leading to specific signatures in the x - ray luminosity, spectra and time variability observed in two very different components : the proper - grb and the prompt emission. using the results obtained in the case of the prototype of the short grb prototype, grb 090227b, we derive the theoretical predictions and the observational diagn
rotational brownian motion is the irregular motion exhibited by a massive particle as it collides with molecules in a fluid.   it is also known as the radial motion of a black - hole binary due to encounters with a single field star that passes within a distance of the binary. here   we consider the second kind of brownian movement experienced by a binary, the irregular variation of the orientation of the binaries spin axis due to repeated encounters. using the conservation equations for interaction of a field star with a massive binary, we derive a relation between the degree of hardening of a binary and the change in its orientation ; this relation is used in conjunction with scattering experiments to investigate the rotation of the spin axis of amassive binary during encounters with field stars.
the transport properties of the electron transport through a driven nanoscale conductor under the influence of time - dependent forces have been studied by means of a floquet approach.   this formalism is applicable to arbitrary periodically driven tight - binding systems and, in particular, is valid for arbitrary driving strength and, as well, extends beyond the adiabatic regime. within this work, we derive explicit expressions for the current and the noise characteristics of the electrons transport through the conductance of a driven system using the heisenberg equations of motion for the electron creation / annihilation operators in terms of the single - particle propagator. for effectively non - interacting electrons, i.e., when no strong correlations between the electron reservoirs are observed, the current can be treated within a generalized floquet theory. for the scattering of a single particle by an arbitrary time - independent potential,   the quantum transmission coefficients for the respective scattering channels are derived from the landauer scattering formula @xcite and its various generalizations. here  , we show that the density of the current fluctuations in the presence of a proper driving field can be controlled by controlling the ac component of the electrical current _ a priori  . however,
diffusive shock acceleration ( dsa ) is an established mechanism to convert bulk kinetic energy into a non - thermal distribution of relativistic particles with a maximum energy much larger than the average energy of particles in the plasma.   we model the emission from radio to x - rays in the southern hotspot of the fanaroff - riley ( fr ) source 4c74.26 using data provided in @xcite and determine that the compact radio emission traces out the location of the shock where the magnetic field@xmath5 is amplified by plasma instabilities up to @xmath2100  at 2  kev, and it damps rapidly downstream of the shocked region. on the other hand,   the synchrotron spectrum between infrared and optical wavelengths implies that the cosmic ray electron scattering length is much longer than the larmor radius and consistent with the amplified magnetic field being structured on very small scales and comparable with the ion skin - depth.
the transjovian objects ( tjos ) are a group of small objects that form out of the debris left over after planet formation, and their physical properties potentially contain information about the early solar system.   the main method of searching for these small objects is through stellar occultations, when they pass in front of a background star, blocking and diffracting its light. because the tjo population is in the distant reaches of the solar system, our ability to observe and understand them is limited. here   we review the current state of the art in the search for tjo occultations with atmospheric cherenkov telescopes ( iacts ), and discuss the advantages and disadvantages of the technique.
the ads - cft correspondence, proposed by maldacena @xcite, has generated a flurry of activity both in high energy and condensed matter physics since it can address issues in strongly interacting systems in the latter ( that are otherwise intractable in conventional condensed matter framework ), by exploiting results obtained in weakly coupled systems.   we study the effects of non - commutative ( nc ) geometry on the generalized ads - Cft correspondence and subsequently on the properties of holographic superconductors, in the presence of both bulk electric and magnetic fields. in this context  , the backreaction of the matter field on the metric is assumed to be suppressed by considering the probe limit.
granular gases are non - equilibrium gases that exhibit behavior reminiscent of conventional phases of matter.   it is often assumed that in the bulk, where the boundaries are far away and spatial gradients are small on the scale of the mean free path of the particles, both heating methods should give the same behavior. here  , we show that there are striking differences in the behavior of granular gases heated uniformly or through the boundary. for a gas heated uniformly,   the velocity distributions deviate from the gaussian distributions that one would expect if the collisions were elastic. using a simulation with a variation on uniform heating, we find a distribution with an exponent of @xmath8 over the whole observed range of velocities, which is unaffected by changes in amplitude and frequency of driving.. this distribution is consistent with the results obtained by rouyer and menon, but is not the same as the ones reported by van noije and ernst, who found a crossover from exponential to gaussian distribution as the amplitude of the driving increased. at present, there is no agreement on what the velocity distribution of a granular gas looks like exactly, nor is it clear what causes the deviations to occur.
we investigate theoretically an experimental scheme based on recent advances in the ultrashort laser technologies which allow to shape laser pulses in femtosecond or even sub - millisecond time scales.   this scheme is based on a pump - probe excitation scheme in which a pump laser pulse prepares a dissociating nuclear wave packet on an ungerade ( repulsive ) surface of a @xmath0  molecule and then a probe pulse is used to photoionize it at large internuclear distance r., scaledwidth=80%. by analyzing the photoelectron spectra we show that the two - centre fano interference in the photelectron spectrum in diatomic molecules is modulated by an interference factor for the quantum state describing a localized electron on a single heavy ( 1836.15 times heavier than the electron ) centre, during the dissociation process, due to localization via coulomb attractive force. since the molecular hamiltonian has also this symmetry we conclude that the state before the turn - on of the probe pulse should preserve the symmetry of the dissociative state prepared by the pump pulse. in other words,   the quantum dissociation state is not a simple product of the hydrogen
the nebula around @xmath0-carinae was discovered by @xcite and the name " the homunculus " arises from the fact that on the photographic plates it resembled a small plump man.   the shape and kinematics of the nebula are explained by the interaction of the winds expelled by the central star at different injection velocities with an aspherical circumstellar environment. in order to model the complex three - dimensional ( 3d ) behaviour of the velocity field of the expanding nebula, we have used a numerical two - dimensional gasdynamic model which takes into account the effects of stellar rotation and the associated latitudinal variation of the stellar flux due to gravity darkening. using the model we have developed a new ad hoc formula for the latitude - dependent wind where the major radius is fixed at 22014  au ( 0.106  pc ) and the equatorial radius at 2100  au(0.01  pc).the radial expansion velocity rises from @x Math6 at the equator to @x math7 in the direction of the wind at which the star is rotating and then decreases again to@xmath4 at the end of the time of the simulation.
multi - user mimo ( mu - mimo ) is a key building block of the next generation wireless communication system.   the multi - user interference, which is the major performance limiting factor of mu - mimic systems, must be managed intelligently using the physical layer techniques such as beamforming. in this paper, we propose an iterative algorithm named mmse - socp, which aims to solve the qos - constrained power minimization ( qcpm ) problem directly. by switching between the downlink and the dual uplink channels  , the algorithm updates the transmit / receive beamformers and powers in the order of updating the transmit power and the receive power. for the single stream case,   both the transmit and receive beamforms are updated exactly after the receive beamformer update. under the assumption of no joint detection at the receivers, the udd algorithm monotonically decreases the total transmit power while satisfying the qs constraints.. however, it is not known whether the convergence of the proposed algorithm to a kkt solution is possible. in order to settle the convergence issue, we present a local optimum solution of the qc pm problem based on the iterative optimization methods @xcite and
the mellin  barnes approach to the evaluation of feynman integrals in the minkowski region has been used extensively for numerical cross - checks of analytic results in the euclidean region, including in two - loop massive bhabha scattering in qed and three - loop massless form factors.   it has also been used to obtain direct numerical results in computations in supersymmetric yang - mills theories : for the four - loop cusp anomalous dimension   and two - loops five - point amplitudes at six loops and beyond in @xmath2 chern  simons theory. here  , we report the implementation of a new software package,  @xcite, which performs the calculation of multi - dimensional integrals with multiple scales in the mid - minkowskow   region using the mellin- and barnes - based approaches. by shifting and rotating the contours of the integrands,   the parametrizations are shifted from standard to tilted, and the coefficients are reduced to finite mellin - barnes integrals that can be computed either analytically or numerically. as a result, the resulting integrals are
the contribution of agns to the far infrared background ( firb ) is investigated using the latest observational data.   the total luminosity emitted by agns can be compared with the mass density of supermassive black holes in order to investigate the average efficiency of accretion in converting mass into energy.
risk averse markov decision processes ( mdps ) are commonly used to solve sequential stochastic decision making problems in robotics and other disciplines.   risk aversion is a key feature of risk - neutral mdps, whereby optimal policies are not guaranteed to be markov stationary but are instead history dependent. in this paper   we consider how the average value at risk ( avar ) metric can be applied when an undiscounted, total cost criterion is used to estimate the risk of a risk - averse mdp problem for a given random value and a predetermined confidence level. by taking into account the fact that the avar metric is a risk metric, we identify conditions for the underlying mdp and define a surrogate mdpproblem that can be efficiently solved and whose solution approximates the optimal policy for the original problem with arbitrary precision. using a rapid robotic deployment task where the objective is to maximize the mission success rate under a given temporal deadline, we validate our findings on simulation results.
the magnetic interaction model of superconductivity on the border of long - range magnetic order has been explored in the copper oxide superconductors @xcite and @xmath2@xcite.   the model predicts the symmetry of the cooper state in the nearly antiferromagnetic state in a quasi-2d tetragonal lattice and is consistent with spin - triplet p - wave pairing in superfluid@xmath0, but it is not applicable to systems with strong spin - orbit interactions or in the spin - polarised state close to the edge of ferromagnetism where spin anisotropy is expected to be pronounced. here   we review the results of numerical calculations of the magnetic interaction between quasiparticles in these systems and discuss the advantages and disadvantages of the model.
we propose a new mechanism for the formation of massive planets around a sun with non - zero eccentricities.   we show that the massive planets are captured after some @xmath0 y and the final eccentricity is non - negligible ( @x Math1 ).    we give results based on high - accurate dynamical simulations about the distribution of the orbital elements of the trapped objects in the disc.
glueballs are bound states of gluons, that are expected to appear in high energy physical processes, as a consequence of the self - coupling of Gluons in qcd.   glueballs are predicted by qcd and are modeled using lattice gauge theory. here   we apply the lattice approach of shannon entropy and its statistical mechanics underlying structure, described in the ads / qcd correspondence @xcite, to the glueball case. for the glueballs,   the model is introduced by a dilaton - graviton bulk action, with a subsequent scalar glueball action. a beta function with an infrared fixed point at finite coupling   is then used in the model. employing the collective coordinates and the structure factor, calculated upon the energy density of the system, the thermodynamical entropy is a foundation to compute the conditional entropy associated with glueball states. on the other hand, the decay process of glueballs ( and other hadrons ) is in general difficult to describe because of the fact that radially excited states, that have the same quantum numbers, get mixed in lattice imaginary time numerical simulations. in this work  , we develop a procedure that leads to a
we present a new theory of einstein gravity based on finsler spacetimes, which provides a generalization of the weak equivalence principle that states that the trajectories of small test bodies are independent of their internal structure and composition.   we develop a consistent gravity theory which determines the finsler function dynamically by means of a generalized clock postulate and point particle action. in particular, we show that finsler spacetime can be used to explain the fly - by anomaly   @xcite in the solar system as well as the rotational curves of galaxies and the acceleration of the universe.
galactic chemical evolution ( gce ) models are useful tools to understand how galaxies form and evolve.   however, dealing with very complex and poorly known mechanisms such as mass accretion, star formation and stellar feedback, brings with it the need for many assumptions and parameters. here   we show that particular imf slopes can be ruled out in the galaxy, whilst a " standard " solar neighbourhood imf is not suitable to describe the high metallicities observed in ellipticals.
the soft - collinear effective theory is used to establish a theoretical foundation of the factorization for b - meson multi - body decays, in particular for @xmath6 decays in qcd.   the proof of factorization is done by using the methods of momentum regions and ward identities.    the results show that the generalized factorization assumption is valid as the leading approximation of an asymptotic expansion.
the origin of the narrow absorption lines observed in quasar spectra has been a major focus of research in recent years.   their large number density along a typical line of sight ( @xcite ) shows a strong evolution with redshift, outnumbering any other known object for redshifts accessible from the ground. at low redshift  , where the detection of galaxies is fairly complete to low - luminosity, a consensus appears that the largest column density  systems are distributed more like galaxies than the low column density ones, and that there is evidence that lower column density systems also correlate with galaxies. here   we show that the two point correlation function for the  forest between lines of sight at @xmath27 on angular scales of @x math28 kpc and @x Math29 kpc for absorbers is significantly larger than that for galaxy counterparts at@xmath30 kpc, which is consistent with the existence of coherent structure on the scale of 100  over a separation of ~0.5 arcmin ( @x maths34 kpc ) ; however, it is not clear whether this scale probes the same clouds or is more characteristic of a correlation length. using high signal to noise ratio
the study of " jets " of particles produced in the final state by high - energy collisions has proved to be a powerful tool for probing the underlying elementary dynamics of the strong force.   the main obstacle to studying jets in heavy - ion ( hi ) collisions is the presence of the huge background given by the underlying event ( ue ) produced simultaneously with the hard nucleon - nucleon collision that initiates the high - transverse momentum jet of interest, which needs to be properly subtracted from the momentum of a given jet in order to reconstruct its " true " momentum. in this article   we give a systematic examination of the performance of several methods to reconstruct jets in hi collisions, applying them to monte carlo simulations for the relativistic heavy ion collider ( rhic ) and the large hadron collider at the hadron centre of mass energies of @xmath9  tev and @x math10.5  teV, respectively.    in particular, we compare the accuracy with which jet momenta can be effectively reconstructed, using several different jet reconstruction algorithms.
the temperature anisotropies in the cosmic microwave background ( cmb ) can provide crucial information on the origin of the universe and help us to discriminate between different cosmological models.   the wilkinson microwave anisotropy probe ( wmap ) 1-year data have been used to study the cmb fluctuations with high accuracy, and the results are consistent with the standard inflationary model. however, recent analyses revealed asymmetries or non - gaussian features which have been confirmed in the 3-year wmap data. among them, a very cold spot in the southern hemisphere has been found to be the main cause of the deviation from gaussianity, using the spherical mexican hat wavelet ( smhw ) analysis. here  , we present a new method for the detection of the cold spot using the smhw analysis, which is based on the use of scalar indices instead of wavelets. at the same time, we propose a new estimation of the kurtosis of the spot, namely @xmath4 and higher criticism, which shows that the spot is the most likely to be driving the bianchi vii@xmath5 template detection.
the fulde - ferrell - larkin - ovchinnikov ( fflo ) phase in pauli - limited superconductors is one of the most interesting properties of these materials.   it is an inhomogeneous phase, where the spin - up and spin - down sheets of the split fermi surface are formed by cooper pairs with non - zero total momentum. here   we report the first experimental verification of the fflo phase in a series of heavy - fermion superconductor kfe@xmath7as@x Math = x2 + 1.5  0.1  nm, which is characterized by a peak in the specific heat @xmath12 at the critical magnetic field @x math2. using this method  , we show that the transition from the bardeen - cooper - shrieffer ( bcs ) state to the f flo phase occurs only in the presence of an external magnetic field, and that the temperature dependence of the phase transition is related to the size of the vortex core and the diameter of the outer edge of the gap function.
we investigate the effects of the density fluctuations and fourth - order phase fluctuations on the coherence properties of quasi - one dimensional bose gases confined in a one - dimensional harmonic trap at mit lab @xcite.   we rederive the known low - energy modes at zero temperature and incorporate the temperature into theory through the temperature dependent chemical potential. using the phase - density representation of the bose order parameter, we calculate the one - body density matrix, phase correlation length and momentum distribution by taking care of the effect of the lower order density fluctuations ( e.g., the four - order term in the phase fluctuations ) and the higher order phase fluctuating phase fluctuations which are important for the dynamics of the trapped bose - einstein condensation ( bec ) as well as the time - evolution of momentum transfer to the system due to a two - photon bragg pulse from the trapping frequency to the radial trapping frequency. under certain conditions, we can form a quasi - condensate of a quasiexperfantastic bec by changing the trapping frequencies and the chemical potentials. with these parameters,   the structure factors and the momentum transfer behavior of the system can be analyzed. also, we
the colour - magnitude diagrams ( cmds ) of resolved stellar populations have been extensively used to infer the star formation histories ( sfh ) of galaxies in the local universe.   the use of hst / wfpc2 and the synthetic cmd method has significantly improved our understanding of galaxy formation and evolution.
the effects of dielectric inhomogeneities on the interactions between charged macromolecular surfaces mediated by the dissolved mobile counterions are studied in aqueous environments.   the influence of these dielectrics on the interaction between charged bodies is analysed using the weak and strong coupling approximations based on the field theoretic representation of the grand canonical partition function of a system composed of fixed surface charges with intervening mobile counterion - mediated interactions. for highly charged systems, the mean - field poisson - boltzmann approach to coulomb fluids is no longer sufficient to explain the observed differences in the behaviour of the counterion layer around charged objects. instead, the two most important recent advances in this field have been the introduction of the concept of  weak and  strong coupling  which allow for an explicit and exact treatment of charged systems at two disjoint limiting conditions whereas the parameter space in between can only be analysed approximately and is mostly accessible only via computer simulations.
the pound - drever - hall ( pdh ) locking method is the most common technique used for locking optical cavities that are operated detuned from resonance by a small fraction of a line width.   however, the error signal becomes nonlinear and even changes sign when the cavity is detune from resonance, making it unsuitable for use at detunings exceeding a small fractions of a lines width. here   we demonstrate a technique where an admixture of amplitude modulation ( am ) and phase modulation ( pm ) yields useful error signals for cavity operations that are on resonance or continuously detuned by many line widths. to determine the error signals from an optical cavity driven with an arbitrary combination of phase and amplitude modulated light, we review the theory of modulated lights from the universally tunable modulator ( utm ), and then derive expressions for the errors for arbitrary detuning of the cavity.
the search for @xmath0-rays from radio galaxies is important for the understanding of the dynamics and structure of jets in active galactic nuclei ( agn ).   even though radio galaxies are agn with jets, their jet is not oriented toward the observer and therefore the radiation produced by the jet does not be doppler - boosted towards higher energies and luminosities, making them more challenging to detect in the very high energy ( vhe :@xmath1  gev ) regime.    the discovery of vhe @x Math0-ray emissions from the radio galaxy ngc  1275 ( perseus  a, 3c  84 ) by veritas has shown that non - blazar agn can produce very energetic photons from non - thermal processes. here   we present a new model for the evolution of the @x math0- ray emission from this galaxy, based on the observations of the vhe emission from other radio galaxies.. the model is based on an inverse compton ( ic ) mechanism, where the accelerated protons in the jet interact with the downstream seed photons with an amplified energy density, because of the doppsler boost due to the relative lore
the influence of environmental degrees of freedom has been identified as the key concept in explaining the classical behavior of macroscopic systems in a quantum framework @xcite. according to this notion a preferred set of localized system states  called the pointer basis  is induced in the course of the interaction of the system with its surrounding.   most characteristically, any initial superposition of these pointer states gets rapidly mixed, while the only states who retain their purity for a long time are the pointer states themselves. here  , we derive the corresponding pointer states which are shown to form an overcomplete, exponentially localized set of basis states, and we prove decoherence to these states using the orthogonal unraveling of the master equation from the ghirardi - rimini - weber ( grw ) model of collisional decoherents. by means of this stochastic process,   we show that the statistical weights of the pointer state are given by the overlap with the initial state. moreover, we demonstrate that the ` candidate'pointer states move on classical phase space trajectories if they are sufficiently localized.
massive stars are rare in the universe, but their high luminosities and mass  loss rates make them important to the ecology of the universe.   it is therefore important to understand what effect leaving the main sequence has on the fundamental parameters of the star. here  , we present a new study of the embedded triple system @xmath0 ori aa ( o9.2 ibvar nwk+o9.5 ii - iii(n ), @xcite, @xficite,@xcite,@rficite ), which has been known to contain multiple components for well over 100 years. by virtue of its proximity and brightness, as well as encompassing the detached binary system aa,   the system is an excellent choice for studying the evolution of massive o stars. using spectra obtained with the international ultraviolet explorer and hipparcos photometry, we have determined the mass and radius of the primary component of the system. while the orbital elements are well constrained, the actual masses and radii are poorly constrained due to the presence of a relatively weak secondary component and poor light curve coverage and precision. this paper is part of a series which will attempt to characterize as rigorously as
a new cooling mechanism for polarisable particles is proposed based on a non - linear fokker   planck equation for the statistically averaged phase - space distribution, which includes friction and diffusion and allows to predict cooling time scales and the unique steady - state distribution.   the system is fitted to a lossy standing - wave resonator with strong transversal confinement where the particles are off - resonantly illuminated by a transverse laser standing wave and scatter light into the cavity. in the absence of a cavity resonance, the particles selforganise in a periodic pattern and the cavity losses are characterised by the decay rate. as a result  , the particle - field dynamics are coupled to the cavity decay rate and can be controlled by a threshold pump intensity that leads to spatial selfordering of the particles into a regular pattern. due to cavity losses this dynamics is dissipative and thus can constitute a new heating mechanism for a very general class of polarisable objects.
non - local transport in superconducting structures is a key issue in electronic devices.   experimental data on this topic are still not well understood. to bridge this gap, we analyze a nisin planar structure using a microscopic model which we solve self - consistently in order to obtain the current profile inside the superconductor in the presence of an applied voltage and magnetic field. by means of this model   we show that the non - local conductance of the s region is dominated by elastic cotunneling ( ec ) or by crossed andreev processes ( car ) depending on the value of the applied bias. for an opposite applied voltage,   the signal is dominated either by ec or by car according to lowest order perturbation theory. as the applied voltage approaches the temperature - dependent gap value @xmath0, the non-local conductance vanishes in this limit. also, when an external magnetic field is applied much smaller than the critical one, both ec and car are suppressed.
many scientific domains rely on the concept of networks to represent an observable state of a system, where networks are usually seen as the outcome of a generative process.   while current technological advances have been making it increasingly easy to collect datasets for large networks, it is difficult to extract models from this data. following conventional scientific methodology, researchers devise models that can account for a network and then test the quality of the model against a number of metrics. in this paper  , we propose a new method for extracting plausible morphogenetic processes from experimental data using genetic programming. by using symbolic regression, we show that it is possible to discover and select plausible morphogenic processes for real - world networks.. the method we propose can be applied to both synthetic networks and on real - life networks. in the case of synthetic networks,   it makes it possible to find the exact generative rule used to construct the particular type of network in question, while in the cases of real - reality networks, its use allows researchers to discover a generatively generated rule that robustly reproduces the original topological features. in contrast with previous works, our approach relies only on local information and uses a parameter - free fitness function without any
graphene, a two - dimensional allotrope of carbon, has created a immense interest in the condensed matter community and in the media since its isolation in 2004 @xcite.   graphene is one of the strongest materials in nature, with literally none extrinsic substitutional impurities, leading to the highest electronic mobilities among metals and semiconductors ( @xmath2 ev ). unlike ordinary semiconductor such as germanium, gallium - arsenide, and silicon, graphene s unusual properties have to be understood before it can really have an impact in technological applications. in this paper   we review the current state of the art in the field of graphene s electrodynamics, which is a mix between a relativistic and a non - relativist problem. using the slater - koster theory, we compute the main matrix elements of the problems in terms of the angle between the@xmath4 hybridized orbitals. in section     we move from molecular orbitals to the crystal and discuss the simplest tight binding hamiltonian for graphene. in sections  and  we show that the problem of hybridization is controlled by the
the speed with which a quantum system evolves from one state to the next is a subject of both theoretical and practical interest.   it has been shown that entanglement speeds up evolution@xcite, but with mixed states these are not always the case. in this paper   we investigate the role of classical correlations and entropy in the speed of evolution of mixed states.we look at a specific model of a bipartite two level system system and examine factors affecting time evolution, first when the system is in a pure state, and then when it is mixed. with apure state the system behaves as expected, but by looking at mixed states we find surprising behavior. for all three classes of states,   the decay coefficient as a function of mixing is inversely proportional to @xmath1, so that the lower the graph, the faster the rate of decay. for mixed states with the identical @x Math1, however, the decay coefficients are not inversely related to the same @x math1, and they are not necessarily a monotonic function of entanglements.    we find that other factors are at work as well, including classical correlations, entropy, and the mixing of the product states.
we rederive the quantum kinetic theory associated to the square - root klein - gordon - poisson system, as already done in @xcite.   a distinctive feature to this reference is that here the evolution equation satisfied by the non - covariant wigner function is set into a manifestly schrdinger - like form. in section   iii the dispersion relation for linear electrostatic waves is obtained. a new quantum modified relativistic factor   is then identified. an application is devised for a mono - energetic beam equilibrium, where the joint quantum and relativism effects significantly alter the wave propagation. in addition the underlying validity conditions and limitations of the model are considered.
the observed high redshift supernovae are significantly fainter than expected for the deceleration parameter, @xmath0, and they are compatible with a medium density, flat universe, where roughly 70% of the energy density comes from vacuum energy.   this is an astonishing result because it means that, taken together with the recent results on neutrino masses from super - kamiokande, there are at least four components contributing almost equally to the cosmic energy density budget : baryons, neutrinos, cold dark matter and vacuum energy.in the present paper we investigate whether it is in fact possible to expel only very elliptical and large grains from galaxies at high red Shift. using a relatively simple model of radiation pressure as a source of dust expulsion   we show that it is not possible to do so, unless very special conditions prevail in the host galaxies. by using our simple model we are able to make the very robust prediction that dust segregation at the level needed to explain the data is not feasible, i.e., enough large dust grains can be expelled from galaxies without simultaneously expelling small dust grains.
accelerating a thermonuclear flame to a large fraction of the speed of sound ( possibly supersonic ) is one of the main difficulties in modeling type  ia supernovae.   numerical results have shown that a prompt detonation does not yield the right abundance pattern to account for the observations @xcite ; consequently, the burning must begin as a subsonic flame. here  , we investigate the effects of the rayleigh - taylor ( rt ) instability on the flame through 2-dimensional spatially resolved simulations in conditions appropriate to the late stages of a type  iia supernova explosion. by using a two - dimensional implicit lagrangian - remap hydrodynamics code with a mixing - length subgrid model to follow a rt unstable flame, we show that the rt instability greatly convolutes the flame front, leading to a significant enhancement of the flame speed. at the same time, the shear layer between the fuel and ash which develops as the instability evolves is kelvin - helmholtz unstable, creating turbulence in the region of the flaming flame. as the flame surface is wrinkled by the rn instability, it will interact with this turbulence, increasing the
the interaction of a moving soliton with an attractive local defect in a fiber bragg grating ( fbg ) is the subject of several theoretical works @xcite-@xcite.   the main objective of these studies was to predict a possibility of trapping a moving ( relatively fast ) soliton by a defect, and thus transforming it into a stable optical soliton, which may be of considerable interest, as, besides being a challenging problem to fundamental nonlinear optics and nonlinear - wave dynamics in general, it may find applications to the design of all - optical memory and logic elements, the trapped soliton playing the role of a data bit. here  , we show that this is possible, at least in the form of pairs of attractive defects, separated by some distance, or, still more efficiently, by pair repulsive local defects, in the case of a single attractive one. for the first time, we demonstrate that the formation of a pair of attractive local defects in the fbg can be achieved by means of a new experimental technique, which is based on the use of a high - energy localized gain applied at the same position where the pinning defect is created.
we propose a comprehensive theory of the relative phase for three - level atoms interacting with quantum fields.   we use the polar decomposition of the quantum amplitudes of two quantum field modes in terms of a polynomial deformation of the algebra su(3 ), which describes two - level systems, to obtain a bona fide hermitian operator representing the phase between the quantum field and the atomic dipole. using this new operator, we show that the reemitted quantum field can be regarded as a selfadjoint operator whose relative phase is determined by the quantum coherence of the atom and the quantum dipole.the results are compared with those of the classical model of atom - field interaction, which is well established in the classical limit.
generalized synchronization ( gs ) is a nonlinear synchronization of two chaotic systems, which is defined by a time - independent nonlinear functional relation between the states of two systems.   experimental detection and characterization of gs from observed data is a challenging problem, especially in biology ; e.g., for study on nonlinear interdependence observed in binding of different features in cognitive process and epilepsies in the brain. in this paper  , we propose a novel approach for analyzing gs based on _ kernel canonical correlation analysis _ ( kernel cca )  which is a version of the kernel methods used in recent years for analyzing data with high nonlinearity. using the proposed method, we show that the nonlinear coupling strength between two unidirectionally coupled chaotic systems can be captured by the proposed approach, and give global coordinates characterizing the synchronization manifold.
the vela - puppis region of the cosmic microwave background radiation ( cmbr ) is a region of intense x - ray emission from the vela pulsar, which is located in the southern part of the galactic far infrared radiation ( fir ) band.   it has been proposed that this region is a hadronic region with a strong thermal component and a bright radio filament running along its edge. here   we review the evidence for a leptonic origin of the signal from the region, as well as the role of relativistic particles in the formation of the radio filament.
massive luminous ob - type stars possess strong stellar winds.   the winds are fast, with typical velocities up to 2500kms@xmath0, and dense, with mass - loss rates @xmath1yr@x Math0. a theory of x - ray transfer in clumped winds that accounts for clumps of any shapes and optical depths was developed by feldmeier  ( 1997a, b ) and oskinova  ( 2004 ). here   we use hydrodynamic simulations to derive the dynamic and thermal structure of stellar winds from the basic underlying physical principle, namely the acceleration of stellar wind by the line scattering of stellar uv photons. as a function of radius and time, the wind density and velocity   are found to be very large because of the strong variations in the wind velocity ( shocks).the variability of accretion rate is much larger than even the strongest variability observed in high - mass x -ray binaries. however, the photoionization of the wind by radiation from accreting object is strongly affected by the wind clumping. in the optically thin case  , it is shown that the photoionicization parameter has to be reduced by a factor @
we investigate the macroscopic motional states of two trapped ions @xmath0ba@xmath1 under the action of laser cooling.   we find that the collective motion of the trapped ions depends on the lamb - dicke parameter ( ldp ), which is the ratio of the recoil energy transfered when scattering a photon and the energy of the vibrational quantum @xcite. with a single trapped particle, distinct phase transitions between macroscopically distinct states   have been observed with different parameters of the cooling lasers @Xcite. for a cloud of ions, changes in the temperature induced by laser cooling cause phase transitions from a crystalline state to an evaporated state. here  , we use the model to find optimized laser parameters for the cooling of the collective motions of two ions of mass in a three - dimensional ( 3d ) harmonic trapping potential using raman cooling @xracite. as a result, the experimental results show that the temperature at which these phase transitions take place perfectly agree with the values calculated from the theoretical model.
the loschmidt echo ( le ) is the revival that occurs when an imperfect time - reversal procedure is implemented @xcite.   the decay rate of the le corresponds to the classical lyapunov exponent, and the perturbation independent decay ( pid ) regime results from the phase fluctuations along the unperturbed classical trajectories. in this review,   we discuss the role of the pid regime in the decay of the echo in a quantum system where the many - spin dynamics are reversed by changing the sign of the local magnetic fields.
the ghost dark energy ( gde ) model of dark energy has attracted a lot of interest in recent years.   the advantages of this model compared to other dark energy models are that it is totally embedded in standard model and general relativity, therefore one needs not to introduce any new parameter, new degree of freedom or to modify gravity. in this paper, the cosmological constraints on the gde model in the framework of the bd theory ( gdebd )   are investigated by using the marko chain monte carlo ( mcmc ) simulation. for each of the constraints, the modified cosmomc @xcite code is used to put the constraints. from the results of the simulations,   it is shown that some features of gde in bd cosmology differ from einstein s gravity ; for example, while the original dark energy is instable in all range of the parameter spaces in standard cosmology, it leads to a stable phase in bds theory.
recently, kilborn et al. ( 2000 ) announced the detection of an isolated compact high velocity cloud, hipass j1712 - 64, with a systemic velocity of @xmath5450kms@xmath6.   this paper presents the new, deep images of j17 12 - 64 obtained from the wide field imager mosaic camera at the anglo - australian observatory ( aat ) using a new data - pipeline based on the isaac newton telescope wide field camera ( int wfc ) data pipeline developed for the hi parkes all - sky survey ( hipass ). to the best of our knowledge,   these are the deepest optical images ever obtained from a single galaxy.
modelling and forecasting electricity loads is a problem well - known within both the academic and the applied statistics community.   the approaches used to model and forecast them vary a lot : some authors work with univariate time series models, while others use a bayesian semi - parametric regression model. here   we present a methodology to improve the estimation and the predictions of a parametric multi - equation model ( similar to the one presented in @xcite ) over a short dataset by using an informative prior distribution.
the interatomic potential for the high - temperature bcc - phase of zirconium is developed using the tight - binding ( tb ) approximation.   the model is based on the moment expansion of the density of states up to the fifth moment, which is the lowest order needed to reproduce the general trends in the elastic constants of hcp and fcc transition metals as a function of band filling @xcite. by using monte carlo simulations,   we calculate the temperature behaviour of the relevant elastic constants and compare them with the available experimental data. while the agreement between the results is rather satisfactory, it does not allow us to draw conclusions about the reliability of the potential. here  , we show that most of the fundamental physics governing the vibrational properties of the bcc-zr is contained in the inter atomic potential model.
the elasto - viscoplastic deformation of amorphous solids is a complex process that couples widely separate time and length scales.   the most successful methodology for bridging over these widely separated scales is equilibrium statistical thermodynamics, but it is not applicable in the case of the large elastosilane - viscosmolybdenum deformation. here   we propose a continuum thermomechanical framework for the elastotransformation of polycrystalline solids based on the recently developed out - of - equilibrium statistical concepts of configurational degrees of freedom and thermodynamic interactions. using the colloidal glass experiments of @xcite, we show that the long time dynamics of an aging glassy material satisfy a generalized fluctuation - dissipation relation with a temperature that is different from the temperature associated with the vibrational motion of the microconstituents ; this relationship is consistent with the existence of a well - defined " effective temperature " ( i.e. the temperature at which the properties of the mechanical configuration are most closely related to the thermal fluctuations ). by taking into account the fact that the structural order of the plastic deformation is determined by the slow shear -
the problem of parameter degeneracy in measuring leptonic cp violating phase and t violation in neutrino oscillations is a well - known one.   it is well known that there exist two sets of degenerate solutions ( i=1, 2 ) even if the oscillation probabilities of @xmath10 and its cp conjugate, cp@xmath11 \equiv p(\bar{\nu}_{\mu } \rightarrow \bar{\ nu}_{e})$ ], are accurately measured. to determine the optimal solution to this problem, we use the " cp and t trajectory diagrams in bi - probability space " for pictorial representation of cp - violating and cp - conserving phase effects as well as the matter effect in neutrocyte oscillations. using these two types of trajectory diagrams  , we show that they provide a powerful tool for understanding and analyzing the problem of parameters degeneracy, as partly exhibited in ref.@xcite.
abstractthe photometric signal of transits by the low - mass companion of hd  209458b was discovered in 2000, and the discovery made possible a number of unique and important follow - up studies, based on more subtle changes in the received starlight that should occur during transits.   we have now used this technique to search for h@xmath0 absorption from the hydrogen exosphere of Hd 209458b.we have observed a @xmath11% increase in the transit depth in the yellow light of the sodium resonance doublet in the 0.3    band, which is caused by the passage of a small fraction of the starlight through the atmosphere of the planet. at the same time, the temperature of the exosphere has increased by ~5  k above the earth s surface, and an apparent blueshift of the absorbing atoms has been observed in the uv - visible spectrum. using a combination of spectroscopic and theoretical calculations, we have established upper limits for the absorption of h#@x Math0 ( 6563   ) in the balmer lines of the stellar spectrum, which are consistent with the results of the lyman-@x math
the einstein equivalence principle ( eep ) postulates that fundamental physical laws are invariant in space and time.   however, some of new theories beyond the standard model of particle physics suggest a violation of the eep. to test the validity of eep in astrophysics, we used the alkali doublet method to measure the relative variation of the fine - structure constant, @xmath0, obtained from optical spectra of quasars with a new generation of giant telescopes at the vlt, keck, and subaru telescopes. for this purpose,   frequencies of two or more lines with different dependence on the fundamental constants are compared to each other in time to monitor a relative frequency shift,@xmath16. using the many - multiplet method which utilizes absolute laboratory wavelengths arising from many different multiplets in different ions, we found that the present - day upper limit of the relative variability of @x Math0 is limited to a few @x math14 at redshift @x maths15.. a further improvement approximately by an order of magnitude can be expected only with the new high - resolution - ultra - stable spectrograph espresso at the Vlt, whose commissioning will start in
supercontinuum generation ( scg ) in silicon on silica nanophotonic waveguides is investigated by controlling the group velocity dispersion ( gvd ) along the pulse propagation distance.   the effect of the waveguide width on the gvd is studied using a genetic algorithm and the results are compared with those of single mode photonic crystal fibers ( pcfs ), in which the dispersion properties are optimized to allow for the generation of broad and flat coherent supercontinuum.
the bayesian approach is becoming a popular technique to solve problems in data analysis, model selection and hypothesis testing.   the application of variational methods to bayesian problems results in the variational bayes ( vb ) algorithm. here   we further study the use of Variational methods in the context of bayesian approaches, focusing on data clustering problems. for two - sides clustering real value data and for clustering data represented by a hypergraph or bipartite graph  , we obtain a vb algorithm. depending on our starting statistical model, either the vb or the expectation maximization ( em ) algorithm provides an approximate solution to the inverse inference problem. because of its bayesian root, the v b algorithms have a built in correction for model complexity or bias and, therefore, they do not require the useof additional complexity criteria.. the performance of the vB algorithms is tested in some examples, obtaining satisfactory results whenever there is a significant distinction between the groups.
inflation @xcite is a successful paradigm for explaining why the universe is so big, so old, and so flat.   it provides a mechanism for generating the primordial cosmological perturbations, but the fundamental physics responsible for inflation remains elusive. in this paper  , we derive an extended version of the lyth bound on the variation in the inflaton field during inflation in terms of the ratio between tensor and scalar perturbation fluctuations generated during inflation, known as the _ lythbound_. using slow roll theory, we find that the field variation during the inflationary period is generically of order, even for models with a very small tensor / scalar ratio. at the end of inflation,   the rate of field variation is rapid enough to ensure that the last e - fold of expansion is sufficiently fast to allow for the introduction of a small self - coupling or a hierarchy of mass scales into the lagrangian. by contrast, when the field rolls off a local maximum of the potential, the amplitude of the oscillations is strongly suppressed relative to the observed amplitude of tensor fluctuations.. these results are consistent with the theoretical prejudice based on effective field theory,
cyg x-1 was observed on 12 january 2000 ( mjd = jd - 2400000.5 = 51555.34 - 5.51 ) with the high energy transmission grating spectrometer ( hetgs ) on the _ chandra _  x - ray observatory.   the absorption lines of highly ionized species of s, si, mg, ne, and fe are redshifted by 300 to 800 km / s but are generally consistent with the weighted mean : 460 @xmath0 10 km /s.    the column densities of the photoionized plasma are systematically lower than those of the corresponding h - like ions, which could indicate that the photoionic plasma has been formed through a low density ionized gas that is associated with cyg X-1.
general relativity ( gr ) effects on the aligned pulsar magnetosphere are studied using particle - in - cell ( pic ) simulations.   we first construct a force - free simulation of the aligned rotator in @xmath6 using the general relativity code @xcite. to estimate the strength of the effects of general relativity on the alignment of the current density along the magnetic field, we run the simulation in kerr metric and show that the polar pair cascade is restored in general relativity.
directed flow measurements for charged kaons in au+au collisions from the star experiment at the relativistic heavy ion collider ( rhic ) in the range @xmath10 7.7 to 200 gev are presented as a function of rapidity and centrality.   the measured directed flow is the first harmonic coefficient of the fourier expansion of the final - state momentum - space azimuthal distribution . here   we report the results of directed flow measurement for charge - neutral kaons with high precision for central ( 0 - 10% ), intermediate - centrality ( 10 - 40% ) and peripheral ( 40 - 80% ) au+ao collisions at@xmath1= 7.9 - 200 g ev.    the measured data are compared with the theoretical data obtained from the same energy range using the nuclear transport models hsd, phsd and urqmd which show that the experimental results are not consistent with the model calculations since the event plane used in the experiment does not exactly coincide with the known reaction plane in the theory calculation.
we summarize the constraints obtained on wind clumping in hmxbs using the hard x - ray variability observed by the ibis / isgri instrument on board integral @xcite.   we analyzed the available integral data for 12 candidate super - giant fast x - rays transient ( sfxt ) systems that have large variability factors and compared them with the classical and absorbed underflow roche - lobe underflow,super - giant hmxb ( sghmxb ) systems, which have a typical variability factor of @xmath4. as the sources are flaring at most once per day, their average hard x-ray luminosity is very low and the free - fall time from the accretion radius towards the compact object is of the order of ~1.5 to ~2.5 years. since the interaction of a compact object with a dense clump formed in the wind of a massive companion leads to increased accretion rate and hard X - ray emission, the flare duration is therefore very probably linked with the thickness of the clumps which, for a clump radial velocity@xmath13, is @x Math14.    the clump density at the orbital radius can be estimated as
we consider two - flavor neutrino oscillations within the framework of quantum estimation theory ( qet ) and analyze the estimation of the mixing angle @xmath0 which characterizes them.   we will consider neutrinos produced in a definite flavor and two types of models for the ensuing neutrini oscillations :   the standard plane - wave model ;   a " decoherence model " which takes into account the essential feature of wave - packet models, which is the dynamical suppression of coherences between different neutrine mass states and the corresponding damping of the flavor oscillation probability. in both cases  , we will calculate the quantum fisher information ( qfi ) and the population measurement Fisher information ( pmfi ), which quantifies the sensibility of this commonly used protocol for the estimation at specific times - of - flight and the maximum precision achievable with it. for models of type ( 2 ), where the projectors onto eigenstates of the symmetric logarithmicrometer derivative ( sld ) can be physically interpreted, direct mass measurement will be shown to be the scheme which realizes the qfi, and the pmfi is optimized for both models at specific
the two best studied variants of the massless gross - neveu ( gn ) model @xcite differ by their chiral symmetry groups.   the first model has the lagrangian @xmath3 throughout this paper, we are always in 1 + 1 dimensions and suppress contracted  color " labels on the fermion bilinears ( 1...   @x Math0 ).. the second model has a continuous u(1)@xmath6u(2)@Xmath2 chiral symmetry and is often referred to as two - dimensional nambu  jona - lasinio ( njl@x math7 ) model.    the same theory is also exactly solvable in the large @x maths0 limit, see the recent paper @xaite. here  , we consider the generalization of the gn model to two flavors : it is the njl - type model with u(2).the solution of the u( 2)-njl model is expected to be simpler than that of the su(2)-njc model.
it is expected that sim will achieve the @xmath0as mission accuracy in determination of parallaxes to a nearby stars. here   we would like to analyze whether or not the future sim astrometric accuracy will be compromised by the spacecraft navigational errors.   analysis of tolerable errors for position determination in a general case is a complicated problem and should be addressed by using a formal numerical treatment. however, we may simplify the task by analyzing a special case which is expected to provide the most stringent requirements on the positional accuracy.
the study of collisional relaxation in stellar nuclei around massive black holes and the associated rates of capture has a long history.   the pioneering work of @xcite established a quasi - steady - state solution for the stellar distribution, now known as a bahcall - wolf cusp, which is characterized by zero ( or very small ) flux of stars with respect to energy into the central hole. here   we review the results of studies based on the one - dimensional fokker - planck equation describing two - body relaxation and energy exchange between stars in the ( newtonian ) gravitational field of the massive object, and discuss the consequences of the neglect of the third integral in the axisymmetric problem.
we have studied the asymmetry factor of the time structure of the signal in the water - erenkov detectors of the pierre auger observatory for proton and iron initiated showers.   we have found a new observable related to this factor, which is a measurement of the logarithmic rate of change of the variable considered, and it is a function of the core distance and the atmospheric depth. using a taylor expansion in slant depth around @xmath16, we obtain :@xmath17 if @x Math18, the asymmetric factor @x math19 depends on the core distances and the atmosphere depth, and its magnitude is strongly dependent on the muon to electromagnetic ratio at ground.
wavelets are a new mathematical tool that has proved to be of great help for noise reduction in digital signal / image processing.   the basic idea behind wavelets is that they provide a multi - resolution view of the signal. using wavelets   we can thus remove most of the noise without altering the inherent structure of the signals, and we can do this very quickly because the algorithm is even faster than the fast fourier transform. by de - noising the noise in the signal at each timestep  , we can reduce the number of particles needed for a simulation with two orders of magnitude more particles compared with the real number of particle @xmath0.. we provide convincing evidence that our wavelet method works so successfully by making a detailed prediction and carrying out three hard tests : one concerns the onset of a gravitational instability, the other two concern the heating and accretion following the fragmentation of a cool galactic disc, and the third concerns the formation of a black hole. while the prediction and the tests are specific to disc galaxies, our approach is also expected to work successfully when applied to cosmological and plasma simulations.
we present a new approach to the approximation of a marginal distribution using markov chain monte carlo ( mcmc ) and importance sampling type correction of the output.   we focus on bayesian state space models, where importance sampling and particle filters are used for correction. in order to ensure the validity of the estimation,   the outcome is corrected with importance sampling - type estimates. as a general rule, we recommend an approximate method for estimating the marginal distribution based on the mcm cmsc approximation of the importance distribution.    we detail minimal requirements which lead to strongly consistent estimators and give general conditions under which central limit theorems hold.. we also show that the setup is useful much more generally, for instance in latent variable models or discretisations of continuous models, such as diffusions or inverse problems.
globular clusters ( gcs ) are the oldest stellar systems found, with ages in the range @xmath3 to@xmath4 gyr, so to represent tracers of the early formation history of the galaxy.   they are the best systems to study stellar dynamics, having relaxation times smaller than their age, so that, at least in the core, stars are expected to have lost memory of their initial conditions. since shapley s pioneering work @xcite, globular cluster models have played a key - role in our understanding of the evolution of the universe and of the manner in which our galaxy formed. here   we review the recent findings of two tidal tails emanating from the outer part of the palomar 5 globular system, which show the presence of clumps of stars in their tails, and discuss the possible mechanisms of their formation.
we study the morphological instabilities of a dislocation - free, one - dimensional, single - crystal, epitaxially strained thin solid film in a wetting interaction with a solid, semi - infinite elastic substrate.   we show that the film thickness and the wetting length are two _ independent  characteristic lengths, i.e. the former length is determined by film deposition, while the latter one is determined from the molecular structure and properties of the film - substrate interface. for wetting ( non - wetting ) films, the solution of the elastic free - boundary problem with boundary conditions that include wetting stress terms results in additional destabilizing ( stabilizing ) contributions in the dispersion relation. in this case  , the perturbation wavelengths may be comparable to the deposited film thickness but still much larger than the Wetting length. in these cases, the long wavelength approximation may hold with respect to the wetts length, but not with respects to the film thickening.
the ability to predict the conditions under which a material will yield is of great fundamental interest and technological importance. over the past three centuries, a number of yield criteria have been formulated that predict whether a combination of stresses on a solid will produce irreversible deformation. in this paper  , we use molecular dynamics simulations to test the applicability of these criteria to amorphous polymer glasses under multiaxial loading.   we find that the pressure - modified von mises ( pmvm ) criterion is the most commonly used for predicting the yield of polymers. however, the tresca criterion ( pmt ) and offset stress ( offset - stress ) are also well described by the pmvm criterion. at low temperatures,   the pmt criterion gives a lower yield stress than the pm vm criterion, but at high temperatures, the pmmethacrylate ( pmma ) criterion shows the best agreement with the pmv criterion.
the current paradigm of an exponentially expanding universe implies that large - scale, gravitationally bound structures will eventually become causally disconnected from each other, forming island universes scattered inside a mostly empty universe. in our previous paper ( @xcite, hereafter  paper i " ), we presented a criterion to determine the limits of bound structures, defining superclusters as the biggest gravity - bound structures that will be able to form.   this criterion defined a critical density contrast over which a spherical shell will stay bound to a spherically distributed overdensity, and can only be applied to data given in real, three - dimensional space (  real space " ). here   we present a way to apply our theoretical criterion to redshift - space data, permitting its application to Redshift surveys.    the new criterion is based on the geometrical appearance of the real - space criterion as seen in redshift space, and needs to be calibrated using statistics from @xmath0-body simulations to account for velocity dispersions not considered in the theoretical model presented in paper i.see research article http://www.biomedcentral.com/1471-2148/7/8/9/11/
loop quantum gravity is a canonical quantization of the classical theory of general relativity.   it turns the classical metric and extrinsic curvature into operators on a hilbert space which are then transformed into new basic fields, given by the _ ashtekar variables, the densitized triad, and the spin connection. in this paper   we show how to use these new variables to develop a set of complete scenarios for the behavior of a universe close to a classical singularity.
the electro - mechanical coupling in nanoelectromechanical systems ( nems ) is typically rather weak and although there are important examples where non - linear coupling plays a significant role, in many cases a linear description is sufficient. in this paper   we use a simple model system consisting of a nanomechanical resonator linearly coupled to a normal - state single - electron transistors ( sets ) to explore how even very weak linear electro-mechanical coupling can give rise to a strongly non -linear response when the resonator is driven close to resonance. in the weak - coupling limit and in the absence of driving,   the set acts on the resonators like a thermal bath with an effective temperature proportional to the bias voltage ; it also damps the mechanical motion and renormalizes the frequency of the resonate resonator.   for drives above a certain threshold the mechanical response as a function of frequency becomes stronglynon - linear and the mechanical system displays many of the characteristics of the duffing oscillator :@xcite frequency pulling, a strongly asymmetric line shape, hysteresis and bistability. exploiting the fact that the underlying electro - mechanics coupling is very weak, we describe the
recent results from the relativistic heavy ion collider on the suppression of high transverse momentum hadrons in central heavy ion collisions at @xmath1   @xcite, which are being attributed to energy loss of hard scattered partons in the dense medium created in these collisions, have received a lot of attention.   it has been proposed that these effects may be explained by a collective production mechanism, namely  recombination  or  coalescence  ( called " reco " below ). in the reco mechanism hadrons are made through assembly of existing quarks or antiquarks, and this is further enhanced compared to fragmentation due to the penalty the latter receives because a colored object ( the parton ) tries to pull away from another color source and loses energy in the field. for the production of color singlets reco deals with the formation of baryons which do not suffer such interaction effects. here   i discuss the possible mechanisms underlying these observations.
the kagome geometry presents one of the most highly frustrated quantum spin systems achievable in two dimensions ( 2d ) with only nearest  neighbor heisenberg interactions.   the @xmath0 = 1/2 kagomite lattice has been found to have a spin  liquid ground state,@xcite, whose ultra  short spin   spin correlation lengths are effectively those of a dimer liquid and whose excitation spectrum shows a manifold containing an extremely large number of low  lying singlets. here   we investigate the effects of static impurities in the kagomer lattice on the dynamics of dimer   dimer correlations in the presence of ga@xmath10, spinless impurities. despite the very short intrinsic spin  spin correlation length, dimer Dimer correlations   develop over considerable distances in the absence of dopants, and we show that there is no evidence for free local moments induced around impurity sites, and that a highly unusual effective repulsive interaction arises between such holes in the spin background.
baryonic matter is the dominant baryonic component of present day galaxies, but it is not well understood whether this is due to poor retention of baryons, of the low efficiency of gas - to - stars conversion, or of a combination of both.   we show that the baryon retention fraction in low - mass halos depends strongly on the mass of their host halo, and that the average value of the galactic stellar mass function ( smf ) inferred for these halos never exceeds @xmath13%. using data from the two degree field galaxy redshift survey ( 2dfgrs ) and the sloan digital sky survey ( sdss ), we find that the smf decreases with decreasing star mass, and increases with increasing cold gas mass.    we propose that the observed decrease in the smmf is a result of the transition from a " stellar - mass  dominated to a " cold gas  dominated" galaxy, which is caused by the accretion of cold gas into the galaxy, and the subsequent reduction in the abundance of stars as a function of star mass.
the notion of boxicity of graphs was introduced by roberts @xcite.   it has applications in some research fields, like niche overlap in ecology and fleet maintenance in operations research. recently, chandran et al. proved the relation between boxicity and chromatic number under the generalized mycielski s construction. here   we consider whether this relation is similar to that of chromatic numbers under the generalization of the focalization of graphs. for a complete @xmath0-partite graph,   the boxicity is at least that of a graph with @x Math12 vertices.    we observe that the boxivity of the generalizedMycielskis of a complete@xmath5-partitie graph is more than that of its induced subgraphs. as a consequence  , we give an upper bound and a lower bound for theboxicity of our results.
the kuramoto model of globally coupled ( all - to - all ) phase oscillators with a time delay and subject to the ornstein - uhlenbeck ( ou ) colored noise @xcite, that is a gaussian process with a finite correlation time, and a non - gaussian colored noise@xcite is considered.   the effect of the time delay on the onset of synchronization is investigated for different noise strengths for both ou and non -gaussian noises. in this paper   we show that the influence of the ou noise qualitatively differs from the case of white noise as the former allows for the full synchronization despite the fact that the system is subject to a noise while the latter allows for only partial synchronization when the intrinsic correlations are small. by taking into account the effects of noise and time delay  , we demonstrate that the critical coupling of the system grows nonlinearly with the increase of theTimeDelayed interactions. also, we investigate how the transition from the gaussian to the non - Gaussian noise changes the dynamical properties of the systems.
we describe a new scheme for the use of a dual - frequency modulation ( dfm ) method for the absolute - length stabilisation of an optical cavity for measurements on timescales reaching from several seconds up to hours.   the technique is based on locking the frequency difference between its n@xmath0 and its ( n+1)@x math0 longitudinal mode by using an acousto - optical modulator at a fixed value matching half of the free - spectral range of the reference cavity. in order to avoid a long - term drift of the laser frequency  , we have chosen to stabilize the length of the referent cavity by locking the rate difference between two eigenmodes of the same laser at frequencies largely beyond 100  mhz.the described method is independent from the existence of nearby atomic transitions and allows to obtain excellent frequency stability for periods up to an hour.
quantum chromodynamics ( qcd ) and random matrix theory ( rmt ) are two seemingly unrelated theories.   they are both strongly interacting, relativistic quantum field theories that describe the weak and electromagnetic interactions among all elementary particles. in this short introduction   we would like to introduce the two players in the title, rmt and qcd, on a superficial level, and give a motivation why and where it will be beneficial to relate them.
the measurements of photon structure functions have a long tradition since the first of such measurements was performed by the pluto collaboration in 1981.   the investigations concern the qed structure of the photon as well as the hadronic structure. here   we review the results from the four lep experiments on the structure of quasi - real photons, which are based on the measurement of deep - inelastic electron - photon scattering events in which a pair of muons is produced by the @xmath14 system. for the last few years  , the experimental data have been updated with new parametrisations of the effective structure functions of the quasiexperimental and the virtual photons. at low values of@xmath2, the main areas of interest are the behavior at low momentum squared values of @x Math2 and the evolution with the momentum scale, which is predicted by qcd to be logarithmic.
in the past two decades there has been a lot of activity in the so called field of quantum chaos, or quantum chaology, where people were trying to understand the essential and significant features of quantum systems which behave chaotically in the classical limit.   this article will be about discussing the possibilities to characterize randomness and dynamical complexity in quantum mechanics and relating this issue to the questions of non - equilibrium statistical mechanics. for example, it has been suggested that exponential sensitivity to initial conditions, the essential characteristics of classically chaotic systems, has many fingerprints in quantum physics.. we shall try to illustrate, mainly by presenting various numerical examples, a possible ` cyclist approach'towards the _ quantum many - body problem _ which is inspired by experiences gained in studies of quantum and classical chaos of one or few particles ( see e.g. @xcite ).
the ability to perform quantum error correction ( qec ) by feedback is a crucial step towards fault - tolerant quantum computation.   two nominally distinct feedback strategies for qec are the measurement - based and driven - dissipative approaches. here   we report an experiment in which we built a feedback platform utilizing a nearly quantum - limited measurement chain and a customized field - programmable gate array ( fpga ) system to perform both measurement -based and driven-dispersive feedback schemes within the same setup. using this platform, we stabilize an entangled bell state of two superconducting transmon qubits@xcite with the help of repeated active correction through conditional parity measurements. by performing both schemes on the same hardware setup and circuit qed ( cqed ) system @xcite, we shed light on their close connection and compare them on a level playing field.
side injection of a low energy electron bunch to the wakefield at a small angle is a promising technique for improving trapping efficiency of proton driven wakefield acceleration.   the theory of side injection is essentially two - dimensional, and the one - dimensional hamiltonian approach of @xcite helps to some extent to identify rough scalings, but quantitative results necessarily rely on simulations. in this paper   we make a step toward creation of a two - dimensional trapping theory and formulate necessary conditions for side injected electrons to penetrate into the Wakefield.. we assume electrons are injected at a very small angle ( ~0.5 cm ) to the direction of driver propagation and show that there is an optimum value of this angle., we also generalize the formalism to laser - driven wakes.
clusters of galaxies are the most massive bound systems to trace the large - scale structure of the universe.   they are also important laboratories to investigate the evolution of galaxies in dense environment and act as natural telescope to study lensed high - redshift faint background galaxies @xcite. for large samples of galaxy clusters,   the determination of optical richness still has a large uncertainty because of difficulties in the discrimination of cluster member galaxies from background galaxies using photometric data. in this paper, we improve the method of detecting galaxy clusters from the sloan digital sky survey ( sdss ; *??? * ) using photometrical redshifts up to @xmath16. by using a new cluster detection algorithm, we identify a cluster richness that is closely related to cluster mass. here, we compare our sample with the previous cluster samples from the sdss, and correlate the cluster richness with x - ray and sunyaev   zeldovich ( sz ) measurements. in addition, we study the brightest cluster galaxies ( bcgs ) and cross - identify them with thesdss luminous red galaxies ( lrgs ).
we present a dimensionality reduction technique called principal component analysis ( pca ), applied to a huge database of synthetic spectra from the gaia eso public survey.   the procedure is applied to more than 800 stars, members of the open clusters ngc3293, ngc6705, and trumpler. using pca,   data can be represented in a fewer number of data points, allowing a fast  nearest neighbor(s ) " search between the observed data set and the synthetic spectroscopy data set.the results show that the method is very sensitive to normalization of spectra, thus an iterative inversion process is required to achieve a fast inversion of stellar parameters of the observed targets.
we derive the _ quantum - jump _ stochastic master equation for a single superconducting cooper - pair box ( scb ) charge qubit continuously measured by a single - electron transistor ( set ).   this master equation describes the random evolution of the measured scb qubit density matrix which both conditions and is conditioned on a particular realization of the experimentally measured electron tunneling events through the set junctions. in this monte carlo method, one takes a trace over environmental ( detector ) microscopic degrees of the freedom but keeps track of the number of electrons that have tunneled through theSet into the drain during time in the " partially" reduced density matrix. to our knowledge, this approach has not yet been formally applied to quantum measurement problems by a set detector. here   we show that the master equation presented here can be obtained by taking a " partial " average on the stochastically derived master equation over the fine grained measurement records of the tunneling processes in the set.. finally, we present some monteCarlo simulation results for the scb / set measurement process.    we also analyze an important ensemble quantity for an initial qubit state readout experiment, @x
in the early 60 s, @xcite published a work that influenced modern psychology by showing that humans violate the laws of probability theory when making decisions under risk.   the sure thing principle was one of the most important laws in bayesian probability theory and was originally introduced by @xcite.  it states that if one prefers action @xmath0 over @x Math1 under state of the world @x math2, and if one also prefers @x maths0 over #1 under the complementary state ofthe world @Xmath2, then one should always preferaction @xMath0 over#1 even when the state of the world is unspecified. in their pioneering work,   @excite realised that the beliefs expressed by humans could not follow the rules of boolean logic or classical probability theory, because humans can not process large amounts of data in order to make estimations or judgements. therefore, the inferences performed are based on limited data coupled with several heuristics, leading to a violation on the law of total probability. in this article  , we will discuss the role of the sure things principle in the problem of violations of the axioms of probability.
the spin - incoherent luttinger liquid ( sill ) is a phenomenon of spin - charge separation where the elementary excitations of the fermionic system are decoupled charge and spin bosonic modes that propagate at different velocities.   the properties of the sill have already been established theoretically,@xcite but the experimental effort has been slowed due to the difficulty of reaching the aforementioned window of energy. in this work   we study the transport properties of a sill in the opposite limit where it is contacted via tunnel junctions to a superconductor and/or a ferromagnet. using hybrid devices consisting of superconductors ( sc ) and ferromagnets ( fm ) coupled to a sill, we show that the interaction between the sill and the leads / sc results in a universal reduction of the conductance of a single - channel quantum wire from @xmath17 to @x Math18.@xaite, and the critical josephson current through such a sill - sc system suffers the same fate : the critical value of the josephal current is halved relative to the spinless lutginger liquid case.    the main results are attributed to
decentralized social networks ( dsn ) are emerging as a viable alternative to centralized online social networks.   however, the widespread adoption of dsn services is still limited due to the lack of a gradual transition path for a user to migrate to a dsn without leaving behind a large portion of his / her friends who are likely to stick with only existing centralized social networks for convenience. in this paper, we propose snsapi, a middleware which enables an end - user to aggregate and stitch together all of his or her online social activities and become a node in a " meta social network " by performing cross - platform socialization over existing social networks such as facebook, twitter and twitter plus other heterogeneous platforms using a meta social networking approach called instantiated - metasn. here  , we describe the design, implementation and evaluation of the sns api middleware and present sample applications built using it to demonstrate its flexibility and extensibility. at the same time, we provide an analytical model to characterize the performance of the system with results presented in section .
leo  i is one of the brightest dwarf spheroidal galaxies of the local group and is the most distant galactic satellite presently known.   the uncertainty on its actual distance is the major contributor to the error budget in this kind of studies. in this paper   we provide a new estimate of the distance to the leo i galaxy using the tip of the red giant branch ( trgb ) as a standard candle, and we derive the distance modulus of leo - i adopting our recent calibration of the method whose zero - point is fully independent from the rr - lyrae distance scale.the data were obtained at the 3.52 @xmath9 italian telescope tng ( telescopio nazionale galileo - roque de los muchachos, la palma, canary islands, spain ), using dolores, a focal reducer imager / spectrograph equipped with a@xmath10 pixels ccd array.    the observations were carried out during three nights ( march 19, 20 and 21, 2001 ), under average seeing conditions. for each observation,   five 300s exposures in i, and two 600 s and three
the new space - time - sensitive radio telescope ( ska ) will be used to search for pulsars in the sky.   the ska will have a sensitivity of @xmath9jy in only 1 min integration time, which is about 10 times smaller than for arecibo and 100 times larger than for the lovell telescope, effelsberg or the gbt. at the low end, this will provide an essentially complete census of the milky way pulsars, but reasonable integration times even allow the discovery ( and study! ) of pulsars with very narrow pulses. as a result, the number of sources that will be discovered and studied will increase dramatically over the next few years. here   i review the major aspects of the science case for pulsar astronomy and discuss the potential applications of the Ska.
we investigate the entanglement dynamics of two peculiar states in the lipkin, meshkov, and glick ( lmg ) model of bose - einstein condensate ( bec ).   the first state is a ferromagnetic coupling where all atoms are either in one of the two modes or equally distributed between both modes. for the second state,   only one atom is in one mode and all other atoms are in the other. using the one - tangle and the concurrence observables, we show that the quantum dynamics of these two states have completely different behaviors depending on the initial state. for this purpose, we introduce the lmg model and discuss its phase diagram which can be easily derived using a semiclassical description @xmath0 mutually interacting spins embedded in a magnetic field. by mapping the phase diagram onto the schwinger representation of the system via the tunneling term, we find that the time evolution of the ground state of the quenched state is much faster than that of the unquenced state.  also, the one- and two - spin entanglements exhibit completely different behavior depending on their initial state : the former is more stable and the latter is more
the detection of r peak in the qsr complex is a preliminary step in the computer - assisted system for electrocardiogram ( ecg ) signal analysis.   one of the most popular methods used for noise removal in the ecg signal is the wavelet transform technique including continuous wavelet transforms ( cwt ), discrete wavelet transformations ( wtrs ), and wavelet package decomposition ( wpds ). in this paper, we propose to study and quantitatively compare the performance of these three wavelet functions on their capability in enhancing q signal to noise ratio and demonstrate its potential application in q detection algorithm of ecg data.
the sunyaev - zeldovich ( sz ) effect is the largest secondary anisotropy in the cosmic microwave background ( cmb ), imprinted by material along the line of sight at redshifts.   we investigate the feasibility of measuring peculiar velocities and cluster temperatures at cm and mm wavelengths in the presence of contaminating sources, focusing on the effects of dusty high - redshift galaxies. using a four - channel reference experiment, we forecast uncertainties for the sz - parameter fisher matrix for multi - frequency maps that contain signals from the clusters as well as noise from the cmb anisotropies, dusty galaxies and the measurement process. to guide experimental design, we vary experimental parameters such as angular resolution, observing time and number and placement of frequency channels. with new experiments providing high sensitivity and high angular resolution   it should be possible to probe other cluster properties, such as bulk velocity and electron temperature.
the copernican principle implies that the earth, and, by extension, the solar system, do not hold a central or specifically favored position in the galaxy s dominant mode of planet formation.   we present 16.6 years of precision doppler velocity measurements for the nearby m3 dwarf gliese 687 ( lhs 450, bd+68@xmath13946 ) with the keck telescope and its hires spectrometer, and we report the detection of an exoplanet with a mass of @xmath2 + 1.5  km and an orbital period of ~1.4  yr. using the keplerian model for these observations, we show that the probability of finding a planet orbiting this star is 95% confidence ( 95% ci : 98%100% ) based on the presence of a planet - metallicity correlation between the star and its parent star, and our results are confirmed by photometric time series data from the automated planet finder telescope @xcite. here  , we use this discovery to motivate a larger discussion of the frequency of occurrence, physical properties, and detectability of low - mass planets orbiting m - type stars.
grs 1915 + 105 is a well - known and somewhat unusual example of a galactic x - ray binary system.   it was first observed in outburst on 1992 august 15 @xcite, and is believed to contain a black hole that is both maximally rotating and rather massive at @xmath3 solar masses. here   we report daily monitoring of the @x Math0-band counterpart of grs 2015 + 105, which has been discovered by using the all - sky monitor ( asm ) instrument aboard the _ rossi x -ray timing explorer _ ( _ rxte _ ) satellite.    our observations span seven seasons, from mjd 51652 to 53969 ( 2000 april 18 to 2006 august 21 ), with a total of 604 individual data points. for each observation,   an ir flux of ~1.5 kev was measured using the andicam instrument and the yale 1.0 m telescope at the cerro tololo inter - american observatory ( ctio ), and for each of the measurements an x - rays count of ~10,000 hits was obtained from the asm instrument. during the observation
the relativistic jets of agns or grbs are known to have two main effects : doppler boosting and deboosting.   the first effect is related to the bright cores of agn and the bursts of grbs, and the second effect is linked to the rapid decays and discontinuous light curves in grbs. here  , we will review the current knowledge about the relativism of forward jets and discuss the possible mechanisms of the two effects.
we report the first " x - ray doppler imaging " of a late - type binary system, made possible by the high spectral resolution and stable wavelength scale of the _ chandra _  high - energy transmission grating ( hetg ).   phase - dependent line profile measurements of the contact binary 44_@xmath0 _  boo, together with temperature - selected light curves, provide powerful new diagnostic capability.
we consider the case of a dendrite which is sealed at its right end and connected to a soma with surface area @xmath5 at its left end.   we use the classical cable equation to describe the electrical potential along the fiber and we find that the optimal shape of the dendrites which minimizes the attenuation of the electrical signal is a cylinder. in this paper, we show that nature is in accordance with mathematics for this problem and solves a shape optimization problem.
the star experiment at the rhic provides full azimuthal coverage at mid - rapidity ( @xmath14@xmath151 ).   it has long been suggested that, due to the screening of the heavy quark potential, the yield of top quarkonium is suppressed in heavy - ion collisions compared to expectations from p+p collisions. here   we review the results of star bottomonium measurements in au+au collisions at @x Math22 gev   @xcite as well as preliminary results in u+u collisions at@xMath26 gev. for each of these experiments,   the nuclear modification factor is calculated and compared to theoretical calculations.. the results show that the suppression of @x math1production in a+a collisions is rather weak from sps to top rhic energies  @xfite, although the uncertainties are relatively high. moreover, the temperature dependence of this suppression is not consistent with the sequential suppression hypothesis, where states with lower binding energies dissociate ( " melt " ) at lower temperatures than states with higher binding energies.
the neutrino emission from a supernova explosion is one of the most important components of the explosion mechanism.   it is believed that neutrinos play a key role in depositing energy above the collapsed core to drive the explosion. here  , we study the role of the fallback from the supernova ( " fallback " ) in determining the neutrinino luminosity arising after the first few seconds of the initial explosion. using a suite of new 2-dimensional simulations of supernova explosions, we show that the fallbacks can be used to estimate the initial mass of the neutron star formed in the supernovae and to calculate the r - rpocess yields for a range of explosion energies and stellar masses. with these calculations,   we find that the mean fallback luminosity is about 1.5 times higher than the observed luminosity at the onset of collapse ( or bounce ) when the material falling back from the explosion begins to accrete onto the proto - neutron star. as the explosion energy and stellar mass increase, the fallouts from the original explosion   are reduced, and the rise in the fallout from this material is much smaller than that from the blast itself.
cosmic - ray ( cr ) particle accelerators are ubiquitous in the universe.   they are seen from a large variety of objects, including the sun, nova and supernova explosions, gamma - ray bursts, supernova remnants, pulsar wind nebulae, relativistic stellar binary systems, galaxies ( and in particular our own galaxy from which widespread diffuse emission is observed ), active galactic nuclei ( agn ), and galaxy clusters. while the ubiquity of synchrotron emission is a clear demonstration that particle acceleration is omnipresent in the cosmos, we still have a poor understanding of where and how the large majority of crs are accelerated. here   we review the current state of the art in the field of cosmic particle acceleration research, with a focus on the very high energy ( vhe ) region of the universe, which is characterised by the decay of hadronic crs at @xmath2  mev and the interaction of the hadronic component with the earth s atmosphere.
quantum monte carlo ( qmc ) methods are a vital tool in the study of many - body systems, providing the most accurate and reliable results for correlated fermionic systems of interest.   however, the application of qmc methods to the calculation of excited - state properties is more challenging, and typically requires the use of an accurate trial wave function with which to constrain the sampling dynamic of the excited state. in this article   we introduce a new approach, whereby fciqmc wave functions are orthogonalized against each other in order to prevent collapse to the ground state. by using a simple gram - schmidt procedure,   simulations for higher energy states are orthotonic against those for lower states, and the results are compared to accurate dmrg results for the carbon dimer in cc - pvdz, cc-pvtz and cc-Pvqz basis sets. while the approach is not affected by a noticeable systematic bias in any of our investigations thus far, we find that systematic improvement to exact results for many excited states is possible.
the rashba and dresselhaus spin orbit interactions arise in materials which lack either structural or bulk inversion symmetry, respectively.   these two kinds of interactions have recently been given a great deal of attention due to their potential role in the generation and manipulation of spin polarized currents, spin filters, spin accumulation, and spin optics. here   we readdress the problem of spin filtering by interferometry in a quasi two dimensional system, and make connection to an experimentally feasible test of these ideas through an electronic mach zehnder interferometer ( mzi ) within rashbae and dreselhaus media where the yang mills gauge point of view is advantageous. using this setup, we derive the conditions for perfect spin filtering that are applicable independently of the incoming spin state and the full energy range of the injected electrons. with the help of experimental parameters, we obtain exact conditions for spin filtering which can be achieved by tuning appropriate experimental parameters. such conditions greatly generalize previous special situations where the spin polarization is a conserved quantity, and show new possibilities for spin filter design.
the measurement of relative positions to obtain the motion of radio sources is one of the most important tasks in space - based astronomy.   the method for the determination of radio source positions is based on the use of a reference frame which is quasi - inertial in that its origin has negligible acceleration and the reference axes have little rotation ; however, the accuracy of the measurements is limited by the uncertainty in the mass of the major solar system members, predominantly the sun and jupiter.    the most convenient celestial reference frame has its origin at the barycenter position of the solar system, and a method must be developed by which observations of celestial objects can be located on this frame. here  , we describe the current state of the art with respect to the measurement of the relative positions of two basic observed quantities, the phase and the group delay.
the ability to coherently transfer atoms out of a bose - einstein condensate ( bec ) in a trapped atomic gas is of fundamental importance in the creation of coherent matter wave generators, often called " atom lasers ".   theoretical interest has developed toward characterizing the out - coupling stage of such an atom laser, with the hope of developing efficiency criteria for this process. in this paper, we set up a general linear response theory approach for treating the coupling of two bose gases at finite temperatures, which gives a formally exact expression for the tunneling current. using the bogoliubov - popov approximation for the single - particle excitations in the trapped bosegas,   we show that the main contribution from tunneling of ions out of the condensates comes from the formation of a pair of correlated pairs of atoms, with one output atom appearing simultaneously with the creating of an excitation in the trapping bose gas.
weave structures consisting of a nano - scale wide, flat, one - way " thread " of the longitudinal - chirality chain of plasmonic particles that rotate in a single plane in the @xmath12 direction are proposed.   the structure is described as a nanoscale wide and flat meta - surface, which can be used to fabricate new types of photonic topological insulators based on edge - states between two bianisotropic metamaterials. for this purpose  , we introduce the concept of broken time reversal symmetry, by suggesting the _ meta - weaves_ being a nano- and one -way " thread" of the long axis of the transverse - magnetic chain. using these structures, we show that the optical behavior of the system is strongly non - reciprocal, with the propagation of the excited dipole in each particle into a cone whose vertex angle is@xmath13 when excited by a point source at the interface of a magneto - optical ( mo ) layer of @xcite and a perforated perferct electric conductor ( pec ) placed at the interfaces of a mo material and a near zero ( enz ) material. from the results
the elastic field mediated interparticle interactions ( section  ) and the interactions of particles with point topological defects in a particle - doped columnar phase ( @xcite ) are calculated.   the results show that the effective of the interactions between the particles in the liquid crystalline host depends on the overlap of the elastic deformations of the particles, and that the effects of the topological defect on these interactions are independent of the order parameter at the particle surface. as a result  , the effect of the boundary conditions on the interaction between the dispersed particles is not well understood.
accretion onto compact objects is highly variable, but in black hole binaries the variability can be particularly dramatic.   disks in these systems exhibit transitions between a luminous state in which the emission contains a substantial thermal component, and a quiescent state dominated by non - thermal emission. to understand the origin of this hysteretic cycle, we have performed numerical simulations of the magnetorotational instability ( mri ) at the interface between the hot accretion flow and the inner thick disk of a black hole binary, and show that the transition from a thin to a thick disk is driven by a strong net field, which threads the inner disk while it is hot and geometrically thick. once a thin disk has formed and the accretion rate has dropped significantly below eddington, the net flux is able to diffuse out radially through the disk, and the hot inner flow is then re - established at a much lower @xmath9. to complete the cycle,   net flux regenerated in the outer thick disk at the interfaces with the adjacent thin disk.. the mechanism for the hysteresis is based on established properties of accretion flows in which angular momentum is transported by the
we study the stability of two  dimensional bravais lattices with high symmetry properties, namely the square lattice and the hexagonal lattice, with respect to classical harmonic vibrations.   we use the nearest  neighbour approximation to derive analytic expressions for the dispersion relations of both lattices. in the case of a finite  ranged repulsive pair potential,   the squares are unstable for all values of the density. in both cases, we present numerical results which show that taking into account more rings of neighbours does not affect the qualitative behaviour of the system. applying our results to a two  dimension system of ultracold composite bosons  , we infer that, for value of the mass ratio and density leading to a crystalline phase, the system crystallises into a hexagonally oriented lattice.
digital predistortion ( dpd ) is one of the most effective solutions for mitigating transmitter nonlinear distortion in carrier aggregation ( ca ) transmission.   the conventional dpd approaches seek to linearize the full composite transmit signal, and hence refer to such solutions as full - band dpd. here  , we present a new method for efficient concurrent linearization of the power amplifier ( pa ) for multi - band transmitters that employ only a single pa @xcite. by focusing the linearization efforts to the most critical spurious emissions only, the processing and instrumentation requirements can be significantly relaxed, thus potentially facilitating the dpd processing also in lower - cost devices such as mobile terminals and other low - cost wireless communication systems.
the formation of black holes during a failed supernova ( sn ) has been assumed to lead to the formation of a black hole with the mass of the star at the time core collapse is initiated.   @xcite recently suggested that this is not the case for red supergiants and that the ejection of the hydrogen envelope following a failed sn of a red supergiant will result in the creation of dust, which will be ejected en masse into the interstellar medium. here   we investigate the effect of dust on the optical properties of the transient from a sn  2008s class of explosive transients using the binocular telescope and find that the observed transient is substantially modified by dust formation, which is almost certainly caused by the re - forming of dust in a pre - existing dense wind after being destroyed by the transient. as a result  , the transient is more likely to be visible in the absence of dust than in the presence of dust because the density of the dust is much higher than that of the envelope, and it is also likely to have a much longer lifetime than the transient predicted by @xmath4-@xmath5.
the effects of adsorbates and vacancy effects in graphene have been a major field of research in recent years.   the formation of magnetic moments near vacancies and hydrogen atoms in graphene has been extensively investigated, both theoretically ( see, for instance @xcite ), and experimentally@xcite. on the other hand, it is known that adsorbate on graphene form ordered arrays in a variety of situations. here   we analyze here the combined effects of the exchange coupling and modified spin - orbit coupling due to hydrogen adsorbations which form a regular array in the @xmath2 supercell of graphene. using a tight binding model, we study the topological properties of the hydrogenated graphene superlattice considering only the local adatom - induced so couplings. by comparing the results of our work with those of previous studies, we show that the structure of the periodic array composed of an isolated vacancy and a hydrogen adatom on top of a carbon atom is not affected by the interaction between the two atoms, but is influenced by the interactions between the adatoms as well as the spin- and exchange coupling. however, the order of the array is different depending on the presence of the adsorbed
in the recent years it has been realized that in mesoscopic metallic systems the electron scattering by some dynamical defects may play a major role in understanding the energy relaxation and dephasing processes of the electrons at low temperature.   such defects can be formed as defects in the bulk region of crystalline materials, or at dislocations, at surfaces due to impurities and also in amorphous materials. in most of the cases   the internal structure of the two - level systems ( tlss ) is unknown and they can behave very differently. here   we review the experimental results of the study of tls in the contact region using point contact spectroscopy and compare the observed behavior with the predictions of the so called slow tls model which is based on the conventional theory of tlrss.. the present review shows that there are many experimental facts which can not be described in that way, and show resemblance to the magnetic kondo anomalies even if their magnetic origin is very unlikely.
coherent scattering of neutrinos on complex nuclei was proposed long ago @xcite as a prominent probe to study neutral - current ( nc ) @xmath0-nucleus processes, but up to now no events have been experimentally measured.   recently, it became feasible to detect neutrino by exploiting the neutral current interactions and measuring the nuclear recoil signals through the use of very low threshold - energy detectors at the spallation neutron source ( sns ) at oak ridge national lab ( oak ridge, uk ). in this review,   we discuss the experimental and theoretical results obtained from the experiments performed at the sns and fermilab.
we propose an experimental scheme to explicitly test the non - locality of very - high - dimensional two - photon orbital angular momentum ( oam ) states by using just @xmath8 detectors.   the idea is first to project the infinite - dimensional 2d state of the quantum system onto several different four - dimensional subspaces, and then to apply the clauser - horne ( ch ) inequality to each selected state. in the present paper   we show that this scheme works well for the case of a thin nonlinear crystal yielding oam - entangled photon pairs, and the two photons are fed into two balanced mach - zehnder interferometers. with respect to those using @x Math5 detectors, the advantages of our method are obvious for the cases of@xmath9 and @x math10.    additionally, we stress that the scheme we propose is designed to realize dichotomic observables.
hidden variable resultant methods are a popular class of algorithms for global multidimensional rootfinding.   they compute all the solutions to zero - dimensional polynomials with complex coefficients of the form : @xmath0 where @x Math1 and @x math2 are univariate polynomial systems in which the roots are well - conditioned and the dimension is small. despite this significant interest, these methods are notoriously difficult, if not impossible, to make numerically robust. in this paper  , we show that any plain vanillaHidden variable resultant method based on the cayley or sylvester matrix is a numerically unstable algorithm for solving a polynometric system. in particular, we identify a numerical instability that grows exponentially with the dimension of @x maths5.    we also show that for@xmath7 the sylvesterster matrix leads to a hidden variables resultant method that can also square the conditioning of a root.
the galactic neighborhood ( gan ) is a local volume of the universe that contains a diverse array of objects ( e.g., galaxies of vastly different masses, morphologies, and star formation rates ).   the study of the interconnection among these constituents is a key part of the gan science. because of their proximity, objects can be observed with unparalleled sensitivities, on small physical scales, across the electromagnetic spectrum, and within a relatively well - determined galactic or intergalactic environment. in this review,   i briefly describe my interpretation of the laboratory astrophysics needs as well as the questions / discovery areas, particularly with consideration of the observing capabilities likely available from existing and upcoming nasa missions.
the detection of gamma rays at very high energies ( vhe ; @xmath1 gev ) from distant sources is a challenge for imaging atmospheric cherenkov telescopes ( iacts ).   however, the detection of vhe gamma - ray emission from sources with high redshifts in the vhe range allows us to test different ( longer than in the lat energy range ) wavelengths of the extragalactic background light ( ebl ) which have not yet been investigated. in this paper   we report the observational results of the distant quasar 4c + 55.17 (@xmath0 ) detected by the magic telescopes using data from the large area telescope ( lat ) on board the _ fermi _ satellite @xcite and the super - fast x - ray spectroscopic system ( h.e.s. ; *????   * ; *????,4c+55.17 ) as a promising high - redshift candidate for vhe emission from the first lat agn catalog ( 1lac ; ~1lac;*??=4c + 56.17).we used a dedicated high - energy data analysis ( private communication,
we study the conductance of a single - atom atomic - sized metallic point contact using parameter - free _ ab initio  calculations.   we use the screened korringa - kohn - rostoker ( kkr ) green s function method supplemented with the baranger and stone formulation of theconductance problem to analyze the eigenchannel decomposition of the current - voltage characteristics of the system. in particular, we focus on the issue on how the valence states of the central atom of a one - atom contact determine conducting channels.. the results show that the number of conducting modes ( eigenchannels ) for a single-atom contact correlates with the numberof valence orbitals of the contact atom which therefore determines the current flowing through the system as measured by scanning tunneling microscopy.
we present density functional theory calculations of the electronic structure of self - assembled monolayers of phenylthiolate ( pt = -s - c@xmath0h@x Math1 ) on noble metal substrates cu(111 ) and au(111).we find significant lateral dispersion of the molecular electronic states derived from the molecular orbitals of the sam.   the electrostatic contribution from the polar molecules as determined by the dipole moment of the isolated array of molecules in addition to that of the bare metal surface is the largest contribution to the workfunction change associated with sam formation, for which we calculate two - photon photoemission spectra.
a new lab experiment based on atom interferometry with a test mass inside a vacuum chamber has been designed for testing modified gravity models@xcite.   the idea is that, even if their nuclei appear to be dense, atoms are so small that the scalar field at the center of the chamber is unsuppressed. additional acceleration on individual atoms due to the chameleon field gradient inside the vacuum chamber in the presence of the test mass could be measured. here  , we provide numerical computations with the following minimal assumption@xmath0 in the outside atmosphere : the chomeleon field reaches its equilibrium value @xmath1 in the space outside the chamber and the klein - gordon equation is solved inside the chamber, the vacuum chambers, the wall and in the air outside the vacuum Chamber.we compare the numerical and analytical profiles of the scalpleur field and the acceleration for various experimental constraints coming from sneeze's cosmological constraints ( experimental constraint=2, chamber size=2 ) and the earth gravitational acceleration(experimental constraint=3).we find that the amplitude of the scalor field inside the cavity is related to the chamber size, in the case where the test masses
we compare the predictions of pairwise and stochastic models for the initial phase of susceptible - infectious - recovered ( sir ) and susceptible - exposed - infectious- ( seir ) epidemics with preventive rewiring among individuals.   we assume that susceptible individuals break off connections with infectious neighbors at a given rate and, in place of them, new connections to susceptible and recovered individuals are created with probability. as for the seir model, we consider two alternative scenarios for the dynamics of exposeds ( i.e., infected but not infectious individuals ) : one where they rewire away from both exposeds and infectives and the other where they don’t rewire at all. in both scenarios,   the degree distribution of the number of contacts per individual changes over time and its mean degree is preserved ; however, the spread of the disease is assumed to be more rapid in the first scenario than in the second. by comparing the prediction accuracy of the two models, we show that the effective degree model developed for the sir model is better able to predict the epidemic threshold than the stochastics model, but the latter has a higher computational complexity.
hydrodynamics @xcite provides a universal description of the long range, long time - scale behavior of a wide variety of thermal systems.   at the same time however, one feature that sets aside relativistic quantum field theories is the existence of quantum anomalies, which cause some classically conserved quantities to be non - conserved. in this paper  , we consider a simpler problem where anomalies enter the hydrodynamic equations already at the linearized level. for a theory with a set of global conserved charges for which the triple correlators contain anomalous contributions, we turn on an external magnetic field coupled to one of the global charges. by using two complimentary approaches, we show that the constitutive equation for the currents is modified in the presence of such quantum anomalies. in an anomalous theory, any current participating in an anomaly now receives a contribution so, in addition to the diffusion and ohmic current, there is a new, dissipationless contribution proportional to the magnetic field and a density of charges. in the second approach, which is appropriate in the weak - coupling regime, we use a single particle spectrum treatment, similar to the " level - crossing " pictures usually used for explaining anomalies   @
we present a new all - sky survey of the extended source catalog of galaxies ( 2mass xsc, ( *???   jarrett  2000 ) of ~1.5 million galaxies with a median redshift of 3.0  kev.   the data are obtained from the @xmath5 sr redshift survey, which is the largest and most comprehensive all -sky galaxy survey in the world. using a combination of three - dimensional ( 3d ) spectroscopy and density functional theory, we show that the 2m++ dataset contains more than 70,000 galaxies at all redshifts ranging from 0.2 to 5.0 mpc, and that the distribution of these galaxies is very homogeneous and isotropic ; this is consistent with the copernican principle of an early universe which was highly homogeneous but inhomogeneous. however, we find that the distributions of the galaxies are not as homogeneous as previously thought, and there is a strong pull on the local group of galaxies towards the center of the universe, which may be due to the presence of high - amplitude large - scale flows of stars and/or low - scale structures. 	 we also find that
the evolution of disk galaxies is significantly influenced by the main features within their disks, notably spirals and bars.   galactic evolution also significantly influences the evolution, morphology, and dynamics of these features. in this paper  , we apply the buta, block, & knapen ( bbk ) method to 17 representative disk galaxies covering a range of early to intermediate hubble types and de vaucouleurs family classifications. using the gravitational torque method ( gtm, buta & block 2001 ), we derive the maximum relative bar torque per unit mass per unit square of the circular speed for each nonaxisymmetric feature alone. from these torques,   we calculate the mean radial force and the maximum tangential - to - radial force ratio, which are then used to derive maximum relative torques for each spiral arm. because the near - infrared spirals often look different from optical spirals with regard to pitch angle, continuity, and symmetry, we have shown that the light distribution at 2.2@xmath4 m emphasizes the mass distribution in the old disk, and the @xmath3-band spirals are more important for bar driving than the ~2.1@x
the classic one - loop triangle abj anomaly for the decay of a spinless neutral meson into two photons in the presence of an external electromagnetic field is corrected by regularizing the lower end of the momentum scale.   the effect of this correction is discussed in the context of the so - called adler - bardeen theorem and the equivalence theorem on the next dynamical level, which states that in the low - energy regime, a pseudoscalar interaction between a spinessive neutral mesons and a fermion leads to the same result for the meson decay into two photon as a pseudovector interaction.
the photometric redshift technique is an efficient and effective way to measure approximately the redshifts of galaxies and to study their statistical properties and evolution.   the technique is a transformation between a set of observable parameters ( e.g., magnitudes, colors ) and estimates of the physical properties of galaxies ( i.e., redshift, luminosity ). with more and more large multi - color imaging surveys, larger and statistically more complete studies of galaxies can be done. in this paper   we describe details of the rcs follow - up observations in @xmath2 and@xmath3 for a sub - area of the red - sequence cluster survey ( rcs, *????   * ) which cover a relatively large area ( 33.6 deg@x Math4 ) which samples a large cosmological volume for galaxies up to redshift @x math15 1.5. by applying an empirical quadratic polynomial photometry redshift fitting method to the rcss photometric catalogs, a photometric catalogue containing about one million galaxies at @xMath17 with relatively small redshift errors can be generated.
using high resolution images at 90 cm and 20 cm, pedlar et al ( 1989 ) have obtained constraints on the relative location along the line of sight of the main components of the sgr  a complex.   they show that much of the thermal gas associated with sgra west lies in front of sgra * and sgra east and that the latter has become optically thick at @xmath2 = 90 cm as a result of absorbing the radiation from the non - thermal source sGra east which is possibly an energetic supernova remnant.
we study the stability of homogeneous einstein and ricci soliton metrics on non - compact manifolds, with respect to the operator from.   we first consider the stability for solutions of ricci flow in terms of dynamical stability, that is, does there exist a neighborhood @xmath1 of@xmath0 such that all ricciflow solutions with initial data in @x Math1 converge to @x math0?   then we study the linear stability of these metrics on some non - compressive manifolds. using the program initiated by guenther, isenberg, and knopf in @xcite, we find that the only non - trivial homogeneous Ricci solitons occur in the non - expanding, expanding, and non - gradient spaces, and all known examples can be realized as left - invariant metrics on simply non - compressible manifolds ; however, the latter are not always considered as " distinguished " metrics because they do not have any topology on the space of metrics. finally, we show that the existence of a neighborhood at a fixed point between the two types of metrics is not sufficient to prove linear stability.
we report here on the results of a search for the lepton flavour violation ( lfv ) decay @xmath5, based on data collected during the 43 days of data acquisition in november and december 2009 by the meg experiment.   the search was performed using data collected from the 590@xmath6mev proton ring cyclotron facility of the paul scherrer institut ( psi ), in switzerland. to select matched photon and positron candidates in a high rate, continuous beam environment and store sufficient information for offline analysis requires a well matched system of front - end electronics, trigger processors and data acquisition ( daq ) software. at the time of the search,   approximately 6.5 10@x Math1 muons were stopped on the target and 22 m triggered events acquired.    the results show that the most likely source of background is the formation of a two - body final state, with the positron and photon being emitted in time and back - to - back in the rest frame of the muon, each with an energy equal to half the Muon mass.  also, a small fraction of the correlated background produces a high energy photon
a family of fixed - point algorithms for the numerical approximation of nonlinear systems of the form @xmath0 is introduced.   the first part of the work, carried out in @xcite, analyzed the convergence of (  ) and showed that the stabilizing factor of the method acts like a filter of the spectrum of the matrix @x Math12 in the sense that :   * the eigenvalue @x math26 of @x maths12 is transformed to the eigvalue@xmath27 of the iteration matrices @xMath28 of ( iterop ). from these conclusions,   several results of convergence can be derived. in this paper, we analyze the acceleration of some of these algorithms by introducing the strategy of minimization of the residual in some norms at each step. as an example, we consider the case of traveling waves generated by the petviashvili type algorithms, where the algorithm is not convergent in general but is able to transform divergent into convergent cases when the stabilization factor is used.
the sdss   rass cluster ( src ) survey is a new sample of galaxy clusters constructed through the unique union of the sloan digital sky survey and the rosat all  sky survey.   the src is a critical first step in the construction of the " virtual observatory" ( vo ) ; for the first time, we plan to perform a joint optical  x - ray cluster selection using these existing, multi  dimensional, data archives at @xmath10. the src will span a large dynamic range in both redshift and mass as well as possessing a well  understood selection function. by using state  of  the  art cluster  finding methodologies, we will construct a sample of @x Math9 clusters and groups that will cover a broad range in Redshift and Mass as wellas possess physically meaningful parameters for these clusters such as x  ray and optical luminosities, lensing masses, velocity dispersions, etc. here  , we discuss the src and its implications for the future of the vo.
the thermodynamics of the bcs to bec crossover problem of a fermi gas with an adjustable attractive interaction is investigated using a local density approximation.   we compare our results with those of recent experiments and show that the entropy as a function of temperature can be used to calculate the critical temperature and the associated entropy per particle for the trapped unitary gas. in addition, we show that starting well in the superfluid regime, much lower temperatures and entropies can be reached by removing atoms from the edge of the cloud, which carry most of the entropy.
we present a simple way to go beyond the mean - field description of rigidity and include local stress corrections.   this is achieved by performing maxwell constraint counting on size increasing structures, starting from the short - range level corresponding to the previous means - field approach.. the analysis reveals two transitions : a first one, at which the number of zero - frequency modes per atom vanishes, and a second one, beyond which stress in the entire structure can no longer be avoided. in between the two transitions,   one can define an almost stress - free network structure for which the fraction of isostatic clusters can be computed. using size - increasing cluster approximations ( sica )  , we show that the orders of these phase transitions are different and depend on the fractions of ring structures. in the first transition, the order of the stress transition is related to what has been previously obtained in the mean-field approach, but the second one is different and depends on the degree of ring structure complexity.
the scattering of thermal and hyperthermal energy heavy rare gas particles from surfaces composed of atoms of smaller mass presents an interesting problem because in these cases most of the incident beam is trapped at the surface and then subsequently desorbed after spending a substantial amount of time in the physisorption potential well.   the purpose of this paper is to carry out calculations with a recently developed theory of gas - surface scattering that can not only treat direct scattering but can also track the initially trapped particles and follow them until they are ultimately desorbing.    the theory treats the trapped particles, those with both positive and negative energy, as a series of successive collisions with the surface while bound in the well. for the heavy gas atoms considered we use the scattering model initially treated by brako and newns for a smooth surface with vibrational displacement corrugations due to the thermal motions of the underlying substrate atoms.the calculations are compared with experimental data for the scattering of well - defined incident beams of xe atoms colliding with molten ga and in surfaces using both total angular distributions and energy - resolved time - of - flight spectra. comparisons with the angular distributions from a ga surface   confirm earlier observations that collective effects require an effective
@xmath2 linear colliders ( lc ) are being proposed for the @xmath3 = tev  @xcite project.   the proposed detector layouts include a large - volume time projection chamber ( tpc ) and a few tracking layers of either silicon drift ( sdd ) or silicon strip detectors for the main tracker ( mt ), and a high - resolution pixel vertex detector ( vxd ) for the high - energy interaction region ( ir ). in all three proposals, the central mt is based on a single tracking layer of either an sdd or a silicon strip detector. at the nlc / jlc proposal,   each train will consist of 190 bunches, separated by 1.4  @x Math1, resulting in a train duration of @x math6265  @Xmath1. at tesla  , there will be 950 long trains of ~950 bunches separated by 337  @ xmath1, and ionization from only a fraction of a single train will be present simultaneously in both the sdd and the tpc. to achieve the best possible performance, it is important to match the trackers to the collision region and/or the v
the theory of motives is a cohomological theory that has been extensively studied in algebraic geometry and arithmetic.   it was introduced by a. grothendieck with the aim to supply an intrinsic explanation for the analogies occurring among various cohomology theories in mathematics, such as hodge theory,@xmath0-theory, algebraic cycles, polylogarithms, @xmath1-functions, galois representations etc. since then,   some new developments of this theory have been found or are about to be developed in number - theory and quantum field theory, with the support of techniques supplied by noncommutative geometry and the theory of operator algebras. in this paper   i give an overview on the theory ( algebraic and analytic ) of endomotives, which is a natural enlargement of the category of artin motives and it is particularly useful as it provides the data of a quantum statistical dynamical system, via the implementation of a _   endomotive_   canonical time evolution, which encodes in its group of symmetries, the arithmetic of the maximal abelian extension of @x math2.
we provide a detailed analysis of the structural properties of toroidal crystals from the elastic theory of defects in two - dimensional curved geometries.   we show that the ground state of a toroidal crystal has excess @xmath3fold disclination defects on the exterior of the torus and@xmath4fold defects on its interior.. the precise number of excess disclinations, as well as their arrangement, is primarily controlled by the aspect ratio of the crystalline torus. since defective regions are physically distinguished locations they are natural places for biological activity and chemical functionalization, a thorough understanding of the surface structure of crystalline assemblages could represent a significant step towards a first - principles design of entire libraries of nano and mesoscale components with precisely determined valence.
we report the discovery of eight new galaxy - scale lenses from a systematic lensed quasar survey, the sloan digital sky survey quasar lens search ( sqls ; *???   * ; *????', by early in 2009.   this brings our total number of known lens candidates to 47, and we have used these new lenses to construct a larger sample for cosmological studies.
entanglement is one of the inherent features of quantum mechanics @xcite.   it is unambiguously a crucial resource and also plays an important role in most of quantum information processing ( qip ) tasks, e.g., bennett1,bennett2. to create entanglement, we propose a method based on the nuclear magnetic resonance ( nmr ) technique using two spin - half quantum bits ( qubits ) which are separable at the beginning and then entangled with each other after some certain quantum operations. here  , we show that the separable state can be used to create entangled states between two non - directly - coupled spins with the aid of one ancilla spin, and most importantly, keeping the ancillary spin never entangled with the data spins.
a detailed description of flow in porous media is essential for building mathematical models with applications in, for example, water management, oil and gas recovery, carbon dioxide sequestration or nuclear waste disposal.   the systems of linear equations obtained from the finite element methods  ( fem ) discretisation are often very large, so that using direct methods is prohibitive and iterative solvers are warranted. in this paper  , we develop a robust and scalable solver for linear systems with the saddle - point structure as in  ( [ eq : sp - matrix}\ ) with the block@xmath7 either zero or nonzero. the solver is tailored to the mixed - hybrid formulation of flow on porous media using the lowest order raviart - thomas ( @xmath8 ) finite elements with combined mesh dimensions ( 1d, 2d and 3d ). in particular, we adapt the balancing domain decomposition by constraints ( bddc ) method to this type of problems, and find that it is efficient for solving the problem.
the large - scale distribution of galaxies has long been used to constrain cosmological models through two - point correlation function ( cf ) and matter power spectrum ( ps ) analyses.   this method is complementary to other methods such as the bao - scale method, and has a power comparable to the baos in constraining the dark energy equation of state. in this paper   we propose to use the pattern of the galaxy distribution to study both the primordial fluctuations and the expansion of the universe. by comparing the shape of the ps at two different epochs, knowing they should be the same, one can find how the universe has expanded between the epochs. for the first phenomenon,   the results are similar to those obtained from the cmb anisotropies and the lss observations, but the size of the initial matter fluctuations is smaller than that of the expansion history. using the second phenomenon, which is the growth of cosmic structures, we show that the distributions of galaxies are more complex than those of the previous two phenomena.. the present and redshift - dependent properties of intergalactic medium, including the integrated sachs - wolfe effect, the abundance of galaxy clusters, the weak
the large magellanic cloud ( lmc ) is the nearest galaxy of the local group with evident star formation activity.   the lmc has a very popolous system of globular clusters that cover a large range of metallicities and ages, ranging from a few million years to 1 gyr. in this paper   we present the results for one of the most massive and luminous globulars in the Lmc, namely ngc 1978, which has been considered for years a peculiar object ( _ i _ ) because of its high - ellipticity ( @xmath8=0.3, *???   * ), significantly larger than the one typically measured in stellar clusters @xcite, and ( _ ii  ) because it has been suspected to harbour a chemically inhomogeneous stellar population =-0.38 dex, firmly excluding the presence of a significant metallicity spread in this cluster. using the advanced camera for surveys ( acs ) on board the hubble space telescope ( hst ) we present a high precision count ( cmd ) of the cluster based on observations obtained with the advanced imaging camera for survey board theHubble Space Telescope ( hsts
we investigated the time lags of the horizontal branch oscillation ( hbo ) and its harmonics of gx  5 - 1 based on the rossi x - ray timing explorer ( rxte ) data.   we found that the time lag behaviors are related to the hbo fundamental frequency. in this paper, we describe the method of data analysis and the results of the cross - spectrum and power - density spectra of the hb and the nb using the rXte data. for the first time, we used single - bit mode, a high time - resolution data mode with @xmath0 s time - resolutions covering four energy bands ( namely 2 - 5.1 kev, 5.01 - 6.6 kev,6.6 - 8.7 kev ; 0 - 13, 14 - 17, 18 - 23, 24 - 249, respectively ), to calculate the pds and cross spectrum of the z source gx / atoll for 11 observations from may 30 to july 25, 1997. by analyzing the data, we found an increase in the time delay of hbo and its three harmonics with increasing fourier frequency, which is due to the
control of self - organized behavior in groups of artificial objects, including autonomous underwater vehicles and groups of autonomous agents, has received extensive attention in contemporary control theory.   it is still unclear, however, how the individual - level behavior and group - level ( macroscopic ) patterns are related. to address this question, we have developed a coarse - grained dynamical model of the self - propelled particle ( spp ), which reproduces the behavior observed in animal groups, but with a much more detailed set of rules for the interaction between the individual agents. using three - dimensional tracking of every individual in a population,   we show that the model can be used to study the formation of emergent patterns of collective behavior in a wide range of biological systems, including fish, honeybees, bacteria, amoebae, birds, wildebeest, and humans.. the model is based on a series of discrete - time rules that are similar to those in the ferromagnetic xy model, and includes a long - range interaction, which is assumed to be global, but local effects are ignored. by controlling the spatial details of the interactions between the individuals, we find that the models reproduce the
the electronic structure of the @xmath1  shell of the cerium monopnictides, cen, is investigated by means of a finite - u extension of the non - crossing approximation ( nca ), including some lowest - order crossing diagrams.   the calculations are based on the lda / gga level of approximation as well as the so called gw   @xcite approximation. in the present paper   we revisit the problem of the electronic structure and the localization - delocalization phenomena of the@x Math1 states for the heavier ce pnictide, cex, where x@xmath2 ( n, p, as, sb, bi ) form in a rock - salt type crystal structure.. the results show that the density functional theory ( dmft ) can be used to investigate the localization  delocalized transitions of the ~0.6 ev binding energy at the fermi level, which are observed in the x - ray photoelectron spectroscopy ( xps ) spectrum of cen. using both the nca and the gw approximation,   these transitions are found to be located in the octahedral voids of
nuclei are a collection of protons and neutrons that interact pairwise, with much smaller, but significant, three - body interactions.   the underlying laws governing the strong interactions result from a quantum field theory called quantum chromodynamics ( qcd ), which is constructed in terms of quark and gluon fields with interactions determined by a local su(3 ) gauge - symmetry and, along with quantum electrodynamics, underpins all of nuclear physics when the five relevant input parameters, the scale of strong interactions @xmath1, the three light - quark masses @x Math2,@xmath3 and @x maths4, and the electromagnetic coupling @x math5, are set to their values in nature.. the fine - tunings observed in the structure of nuclei, and in the interactions between nucleons, are peculiar and fascinating aspects of nuclear physicists.    it is remarkable that the complexity of nucleus emerges from " simple " gauge theories with just five input parameters. for the values of the input parameters that we have in our universe, the nucleon - nucleon interactions are fine - tuned to produce unnaturally large scattering lengths in both s - wave channels
tensor terms are unavoidable ingredients of the microscopic n - n interactions, i.e. those interactions constructed to reproduce the properties of two - nucleon systems.   they are usually neglected when effective interactions and theories are used. in the effective theories some complicated many - body effects   are treated, obviously in effective and average manner, by changing the values of the parameters of the interaction. in this article   we propose an alternative approach to select the strength of the effective tensor forces. using a recursive self - consistent hartree - fock ( hf ) plus random phase approximation ( rpa ) procedure  , we have chosen the strengths of the tensor terms of the effectiveness of the nucleon -ucleon (   n -n ) interaction to reproduce experimentally the experimental value of the 0@xmath0 charge conserving excitation in @xmath1o. with these new interactions   you have investigated the ground and excited state properties of various nuclei by doing hf plus rpa calculations.
the @xmath0 gauge singlet supermultiplet has been added to the minimal supersymmetric extension of the standard model ( mssm ).   the present paper is devoted to a thorough discussion of the model in its version with only dimensionless couplings in its superpotential, and universal boundary conditions for the soft supersymmetry breaking terms at the gut scale. using the most recent experimental constraints on sparticles, higgs and top quark masses from the lep and the tevatron @xcite, we analyze the results of our numerical procedure with the help of analytic approximations and inequalities among the parameters. once the vacua which break colour, electromagnetism or correspond to@xmath2 are forbidden and the experimental constraints are imposed, these formulae allow us to understand the essential features of the bounds on and correlations among some particle masses.. the main results of the careful analysis are discussed.
the charge and magnetic instabilities of one dimensional materials are well understood in terms of fermi surface ( fs ) nesting.   here it is shown that for two - dimensional materials, features in maps of the bare susceptibility can be understood in term of a series of fs ` nesting curves ', and the dominant instabilities are generally related to _   double nesting _ features. the analysis shows how to locate these nesting features in momentum ( @xmath2 ) space, often providing analytical expressions. as an application,   the full evolution with doping of the leading magnetic instices for several families of cuprates is presented, both in the conventional hartree - fock plus rpa ( hf+rpa ) and in a gutzwiller approximation ( ga+rPA ) calculation.    the analysis provides a pseudogap candidate and makes the surprising prediction that the ` checkerboards'seen in scanning tunneling microscopy ( stm ) studies are _ not _ the same phase as the ` stripes'in la@xmath3sr@x maths4cuo@x math5 ( lsco ).
the non - fermi - liquid behavior of the cuprates has two major features depending on the doping regimes : ( i ) near optimal doping no energy scales are present besides the temperature, while ( ii ) in the underdoped regime new energy scales appear in the form of pseudogaps, which persist well above the doping - dependent crossover temperature.   the latter is a consequence of the occurrence of an incommensurate charge - density - wave instability that occurs when the doping is reduced below a critical value and gives rise to the so - called stripe phase. here   we report on some spectroscopic consequences of the strong scattering mediated by charge fluctuations near optimal cycling doping. for the optimally doped cuprates,   these charge fluctuations couple with the spin degrees of freedom of the quasiparticles and give rise to a strong effective interaction both in the particle - particle ( p - p ) and the particle- and hole - hole channels. in the overdoped compounds, when the instability line @xmath20 is approached, a singular scattering between the qu asiparticles is again mediated by the charge fluctuations at wavevectors, with a new doping - independent energy scale. in both cases
diamond - like material is expected to be abundant in the interstellar medium.   diamondoids consisting of up to 11 diamond cages were isolated from petroleum by @xcite making these species accessible to laboratory investigations. here  , we present a new study of the infrared spectroscopic properties of diamondoid molecules using uv irradiation experiments and density functional theory ( dft ) calculations based on the solid - state ir spectra of diamondoids at room temperature and in the hydrogen - terminated phase of the hot gas phase. for the first time,   the ir emission spectra obtained by@xcite along with additional dft calculations have been used to assign two ir features of two different classes of astronomical objects : the unusual ir emission at 3.43 and 3.53 @xmath9 m originating from two objects whose spectra are elsewhere dominated by the well - known infrared emission bands of polycyclic aromatic hydrocarbons ( pahs ), elias 1 and 2, and the inner region of the circumstellar disk around hd 97048 @xa_97048, respectively. as the intensity of the interstellar band   could be correlated with that of the 3.08 @x math9 m band
francis galton, a renowned anthropologist, biometrician and statistician, published an article in the weekly journal of science, _ nature _, of march 7, 1907, about a weight - judging competition conducted at the recent west of england fat stock and poultry exhibition.   he used his method of percentiles to pick out the 95 percentiles of the estimates from the 787 entries for analysis, and found that the middlemost estimate was 9 per cent ( or 0.8 per cent ) of the whole weight too high ; this result was "more creditable to the trustworthiness of a democratic judgment than might have been expected" such a competition provides an early example of the forecast competitions that have become familiar in the forecasting literature. in this note   we take another look at galton s data, and show that his article, despite some inaccuracy, is an interesting precursor of two more recent developments in the statistical forecasting literature : the median on democratic principles and the public choice debate.
the presence of correlated disorder in twinned yba@xmath0cu@x maths1o@x math2 crystals with oriented twin boundaries introduces changes in the thermodynamic properties of the mixed state that go beyond the mass anisotropy approximation.   we show that the vortex solid transforms into a liquid through a first order transition at the melting temperature, @xmath8, and has a hysteretic behaviour both in temperature and field @xcite which corresponds to a superheating of the solid phase @xaite.. however, when the magnetic field is rotated away from the twin planes, the vortex liquid remains correlated in the field direction above the resistivity kink temperature, while the solid - liquid transition is non - linear. using the lindeman criterion and the scaling rules for anisotropic superconductors, we fitted the angular dependence of the temperature at which the kink occurred to the critical end point for the melting line for the bose - glass transition temperature, where the transition between the liquid and solid phases occurs. below this temperature, the v - i characteristics of the liquid state are non -linear and, what is more important, the resistive transitions are hyst
wz sge - type dwarf novae are an unusual subtype of su uma - type dwarfs.   they have properties common to all members of the supermoon family, but are characterized by the presence of early superhumps during the earliest stage of superoutbursts. in this paper, we investigate the origin of these unique characters by considering the quiescent viscosity of the accretion disk and the mass - transfer instability model of the disk - instability mechanism of wz s george's superoutburst ( @xmath0100 d ). using a combination of experimental and theoretical studies, we show that the required quiescence viscosities for the development of the magneto - rotational instability model is very low ( @Xmath1 = 0.01 ), and the observed outburst amplitude and duration are almost identical to those of the normal outbursts, which are usually once in years to decades. however, the maximum outburst amplitude is much larger than expected from the assumed values of the required q2/q3 ratio ( ~6 mag / d ), which is consistent with the observation of extremely long outburst intervals and the absence of normal out bursts in wz
many theorists hold that the superconductivity in quasi - one - dimensional ( q1d ) materials may be explained with the help of non - phonon many - body mechanism @xcite.   yet, there is substantial disagreement about the details of such mechanism and different theories predict different order parameter symmetries : @xmath3,@xmath4-, @x math0-, or @x Math2-wave @xcide.    the experimental findings @xcites have been unable to resolve these controversies.. in this article   we explain why establishing the symmetry of the order parameter is such a hard task. 	 it will be demonstrated that within the framework of the non - Phonon mechanism there are three metastable superconducting states : @Xmath4+-, #xmath0-,#xmath2-, and #x maths4+waves. for each of these states,   the ground state symmetry is determined by the difference in the energy differences between the contesting states. despite the obvious similarities between various families of the q1D superconductating materials in chemistry and structure, despite  universality " of their phase diagram @xc
we have developed a program to measure the age of white dwarfs ( wds ) using data from the all - sky supercosmos sky survey ( sss ).   we use reduced proper motion detection combined with accurate photometry over wide angles to extract the luminosity function ( lf ) for a large sample of wds from the survey data. in order to achieve this, we have used a combination of two different types of image analysis mode software, one that measures 32 parameters for each object detection, and the other that measures only the number of objects detected in each field. by combining these two modes, we are able to identify a total of 6000 wds in the sss, covering over 75% of the sky, and providing information on both the absolute age and the star formation history of the population as a whole. at low magnitudes,   the lf can be used to estimate the cooling ages of wd populations, but is constrained by the marked downturn in the l f at faint magnitudes.    we present our results, and discuss the limitations and possible future refinements of our method.
supermassive black hole ( smbh ) mass estimation is a powerful tool for studying the evolution of quasar populations.   we have recently shown that the quasar mass - luminosity plane is quite complex, and that the virial mass estimates of quasars are not sufficient to estimate smbh masses. in this paper, we use the sharpness of new boundaries in mass to place a tighter upper bound on the statistical uncertainty of virialmass estimates. by comparing virial and reverberation masses at redshift @xmath8, we show that the maximum statistical uncertainty can be estimated from the eddington luminosity of a quasar as a function of its mass. using this upper bound, we find that the theoretical relationship between quasar size and mass is not only weakly supported by the existing data, but also weakened by the existence of several new boundary in the quaserms - mass - lumus plane.
we consider self - similar solutions to smoluchowski s mean - field model for coagulation equations for kernels of homogeneous homogeneity with finite mass in the regime @xmath22 and describe their asymptotic behavior on the whole positive real line.   we show that these solutions exhibit a singular power - law behavior of the form @x math26 with, for example, the number density of clusters of size@xmath14 at time = 0.1 in the case  where the first value problem for the kernel is well - posed for initial data with infinite mass and the mass is conserved for all times. for homogeneous kernels it is furthermore expected that solutions converge to a self - like form for large times. here   this is not the case for the product kernel of homogeneity, which grows linearly at most linearly from the original value problem ( /s1e2b ). by taking into account the existence of a solution for the sum kernel, we find that the oscillatory character of the solutions becomes very explicit and can be interpreted in terms of simple odes coupled with explicitly solvable
the present review of theoretical atomic physics is aimed at astronomers and spectroscopists in general who need to understand the limitations of atomic data.   the present paper tries to give a general, but relatively simple, overview of the most commonly used approximations and methods for the production of spectroscopic data. from the point of view of quantum mechanics   there are two general atomic physics problems to be solved : the atomic structure problem is concerned with the computation of energy levels and rates of spontaneous transition rates among levels of the same ion ( transition rates or @xmath0-values ), and the scattering problem has to do with all different processes that can occur after a collision of an ion with a photon or with a charged particle.the review pays particular attention to the calculation of atomic structure and the spectral processes of photoionization and electron impact excitation. also, the present review emphasizes inner - shell processes that are most relevant to x - ray spectroscopy.
we propose a method of decomposing the radiation energy into work and heat in the framework of quantum master equation ( qme ).   we formulate the method by investigating the time evolution of the system ( called photon drain ) that receives the radiation from the cavity. using this method  , we definitely identify the systematic ( work ) and random ( heat ) energy transfers between the coherent and incoherent parts of the radiation.
the onset of starburst activity in many interacting systems is intimately tied to the formation of global bars, which drive gas inwards to the central regions.   however, a one - to - one correlation between interactions and central starbursts is not evident. here  , i describe how the structural properties of galaxies can influence the gasdynamical and star - forming response of galaxies to an interaction. using @xmath2-body models,   i show that differences in galaxy structure lead to significantly different responses to gravitational interactions. for example, major mergers of equal mass disk galaxies   are thought to result in the most dramatic starburst events, where massive amounts of gas have been driven into their central regions, fueling intense ( l@xmath1   l ) activity. by contrast, the merger involving galaxies with bulges has a very different history of inflow and star burst activity, as the presence of a central bulge acts to stabilize the galactic disks against the growth of bar instabilities ; instead, the galaxies form tightly wound spiral arms which provide a weaker torque on the gas, driving the strong inflow of gas into the nuclear regions. when the galaxies eventually merge, they are gas poor
a continuous water jet falling gently downward through a tap and its subsequent breakup into discontinuous drops is an everyday - witnessed common phenomenon.   there have been many attempts theoretically as well as experimentally to understand the physical mechanism behind the breaking up of jets into drops instead of continuing to keep reducing its cross - sectional area forever. in this work, we set up and conduct an experiment to verify the existence and effect of recoil capillary waves on the length of continuous liquid jet.. the experiments are carried out by damping the recoil capillaries wave using an earlier used method@xcite. after the jet breaks up, the tip of the remaining column contracts to make its shape round once again to minimize the surface energy.    the tip contraction gives rise to an upstream propagating capillary wave which upon reflection at the mouth of the nozzle moves downstream with doppler modified wavelengths. some of these waves with the right wavelength ( as discussed by rayleigh ) cause the liquid column to break producing another contraction of the tip from the lowermost neck of the column and the process repeats once again. for the first time, we show that the recoil Capillary wave can be used to study the effect of external perturbations
the kilohertz quasi - periodic oscillations ( khz qpos ) of the neutron star ( ns ) low - mass x - ray binaries ( lmxbs ) have been detected in 21 sources, including 2 accretion powered millisecond pulsars, 8 z sources and 11 atoll sources.   usually, these khz quasiexperimental oscillations appear in pairs, the upper and lower khz frequencies, which are found to be close to each other or half of the spin frequency. for the all z and atoll Sources,   the data plots of the upper - frequency versus the lower - frequency can be fitted by a power law function, and also roughly fitting by a linear function. however, for the individual khzqpo source, for instance sco x-1, a luminous z source in neutron star low - Mass x -ray binaries, we find that the khzQpo peak separation in a given source generally decreases with frequency, except for the recently detected khz Qpos in cir x-2, in which the peak separation increases with frequency. here  , we investigate the twin khzquasi-periodic oscillations correlation for the single
in the high - energy regime of qcd, an interesting new phenomenon is expected to show up : parton saturation. in this paper  , we would like to investigate how the saturation scale varies in impact - parameter space in the presence of both saturation and fluctuations.   our method will consist in proposing a simple toy model which contains the main physical features of q+cd, which may be implemented as a monte - carlo event generator and for which analytical calculations will be possible. while the model is introduced in the next section, we then provide the derivation of the analytical expression for the correlations between the gluon number densities at different points in impact-parameter space, as a function of the distance between the points and as a result of the rapidity of the evolution of the glucose content of the hadronic object. by taking into account the stochastic effects of the reaction - diffusion process described by the fisher - kolmogorov - petrovsky - piscounov ( fkpp ) equation at each fixed impact parameter,   the results show that the correlation of the global saturation scale between two points increases with the distance from the point where the
liquid metals ( lms ) are attractive low - recycling plasma - facing materials that could protect the underlying solid walls of a fusion reactor from high heat and neutron fluxes.   we have previously shown that, quite simply, and on the net of small corrections, the electrical conductance between two electrodes immersed in the liquid metal scales linearly with the local lm thickness. here, after briefly describing the experimental setup ( sec. ), we extend the measurements to multiple locations, requiring matricial formalism ( sec ) and to multiple times ( sec, ).. the results show that the electrical resistance between each pair of electrodes in a liquid metal can be measured in real time using a labview interface, and that the voltage and current signals are digitized at up to @xmath3 ksa / s and digitally filtered from high - frequency noise ( typically@xmath4500 hz ). as of recently,   the data are available at http://www.ncbi.nlm.nih.gov/pubmed/1471-7007/9/8/5.
the design of the compact receiving array of high frequency surface - wave radar ( hfswr ) is an important issue in the field of industrial wireless sensor networks ( iwsns ).   the size of the received array is very large due to the working frequency of the radar and the wavelength of the antenna. for this purpose,   it is required that the array size is small or limited so that the directivity of the system design requirement can be satisfied. in this paper  , we propose a new array miniaturization design based on circular array as a complementary form of linear array. by combining the advantages of circular array with the advantage of magnetic wsn, the super directivity array has been designed and optimized using the mwsn pattern synthesis method.. the results show that the proposed array design is more efficient than the conventional linear array design.
the first stars of the universe were thought to have formed at zero metallicity.   this is based on the prediction that they would have formed in a state of pair - instability, where the ambient photons in the interior of the star are sufficiently energetic to create electon / positron pairs that can be used to create dynamical instability in the core of the supernovae. here   we review the current understanding of the formation of the first stars, the evolution of stars that will reach this regime, and the predicted observational properties of the resulting explosions. for most of these stars,   the energy of the radiation - pressure - dominated core is sufficient to cause the generation of an off - center shell of @xmath3ni, the decay of which could power the light output. however, for some stars, such as those with massive oxygen cores, the instability occurs after the star has undergone its central helium burning and has formed a massive core composed primarily of oxygen ( with a small mass fraction of carbon ). unlike the case of iron - core collapse, the oxygen in these stars is subject to strong energy release by rapid thermonuclear burning, leading to rapid compression and heating of the inner core of oxygen
we explore new mathematical features of cosmological models with non - minimally coupled scalar fields that admit bounce solutions.   we consider models with the spatially flat friedmann   lematre  robertson  walker ( flrw ) metric. at the bounce point   the period of universe contraction changes to a period of expansion and the hubble parameter @xmath1 is equal to zero and its cosmic time derivative is positive. in such models the initial period of the universe evolution with energies above the planck scale   should be described by quantum gravity because the classical evolution includes the initial singularity, which is a fundamental question of theoretical cosmology. for this purpose   it is possible to obtain bounce solutions in models with minimally coupling standard scalar field models, because in these models thehubble parameter is a monotonically decreasing function. in this paper   our results show that the bounce solutions generalize the integrable model proposed in   @xcite with the ricci scalar@xmath5 as an integral of motion.. the bounce solution is characterized by two conditions : at this point the hubbleparticipation energy of the hub
we study the thermal properties of einstein  maxwell ads charged black holes and find behaviour consistent with field theory interpretations.   we do this for arbitrary dimensions ( greater than 3 ) and determine the thermal phase structure of the corresponding field theories, which correspond to the theories found on the world volumes of m2, d3, and m5branes, respectively. in the planar or infinite  volume limit, the charged black hole solutions correspond to near horizon limits of rotating m2 and d3branes. as the einstein - maxwell   anti   desitter truncation is naturally associated to rotating branes, it is very natural to suppose that there is an associated dual field theory, arising from the world - volume of some branes. here  , we consider the cases of ads@xmath10, ads @xmath11 and ads@Xmath12, which are all related to a rotating brane truncation of the gauged ads supergravity with appropriate compactifications of the yang   mills field theory at strong t hooft coupling.see research article http://www.biomedcentral.com/1471-7007/1741-7006/
the nonlocality of the normalized version of the twin - beam state of radiation produced by spontaneuos downconversion in a parametric amplifier @xcite has been a matter of debate for a long time.   bell s inequalities were originally formulated in the framework of discrete variables, but have recently been applied to systems described by continuous variable systems. here   we apply the various approaches hitherto developed to test non Locality of two- and three - mode continuous variable states.    we focus our attention on tripartite gaussian states as well as non - gaussian bipartite states, which are considered as sources for conditional generation of nonlocal proprties for the nonlocal state of the twb state. using the bell inequalities, we show that the violation of local realism is strong in the first case, allowing the bell factor to reach values of @xmath0, while in the second case enhancement of nonlocity is obtained in comparison with thetwb case.
the online variant of graph coloring is the problem of deciding whether a given graph can be colored with at most @xmath3 colors.   this problem is well known to be np - complete, even in the case with three colors. in this paper   we show that the online chromatic number of a graph is pspace - complete for all vertices of the specified graph@xmath0 if and only if the algorithm knows which vertices are sent and how they are colored so that it can properly color each vertex of the graph @x Math0 as it arrives from the start of the input.
in the social universe, global distances are small, and local interconnectedness is high. in order to find a model that accounts for both of these properties, one could choose a regular lattice whose nodes are indeed locally highly interconnected.   but since global distance is large in this type of network, it is an ineligible candidate for a small world model. yet, through the increased availability of data, it has been found that the simultaneous occurence of high local   global interconnectedness ( i.e.  clustering _ ) is prominent to a much wider class of systems, notably the internet, the world wide web, metabolic networks and food webs. here   we review the recent advances in our understanding of the role of degree related topological properties in epidemic spreading.
terahertz time - domain spectroscopy ( thz - tds ) has a great potential for the investigation of fundamental transitions in organic and inorganic molecules and nanostructures.   the wavelength of the thz pulse in standard far - field implementations of thz spectroscopic experiments greatly exceeds the length scale of the individual objects under investigation, e.g., bio - molecules or nanostructure. to compensate for these constraints, local field enhancements into subwavelength volumes are needed. resonant conducting structures, sustaining localized surface plasmon resonances ( lsprs ), are key in realizing these large local field enhancement @xcite. in this manuscript  , we demonstrate that it is possible to detect and measure the extinction of a single bowtie antenna at the output aperture of a conically tapered waveguide in a standard thz time -domain spectrometer. by using a plane wave polarized along its long axis,   a single resonant antenna can be formed by two triangular monomers with facing apexes and separated by a 5 micron gap. when excited by a linearly polarized thz beam, the antenna exhibits an lspr at 0.4 thz when
we present the radio observation of a sample of 8 ultracool field dwarfs and the detection of the new tight m8 binary lp  349 - 25 at 8.5  ghz ( 3.6  cm ) using the nrao very large array.   the magnetic field properties of this object are compared with those of other fully convective stars, and we discuss the radio emission from this object and its radio mechanism.
the study of entanglement in quantum many - body systems has become a common issue in condensed matter physics, statistical mechanics, and quantum information theory.   the affleck - kennedy - lieb - tasaki ( aklt ) model and its exact ground state known as the valence - bond - solid ( vbs ) state were proposed to understand ground - state properties of the @xmath1 haldane chain ni(c@xmath2h@x math3n@x maths2)@x Math2no@xMath2(clo@x mathematics4 ) ( nenp ) in which the vbs state is a unique ground state and there is an energy gap immediately above the ground state. here  , we present a new method for calculating the von neumann entropy of the reduced density matrix of a quantum system in an entangled state using the aklt model. by means of the new method,   we show that the vts state of the nenP spin chain can be expressed in a form of the matrix product state ( mps ), which is characterized by a hidden topological order and existence of degenerate edge states with open boundary conditions.
we present a new approach to the calculation of the widths of the qhps from a model which is purely based on the electron - electron interactions, supported by the local ohm s law  @xcite.   we solve the schrdinger and the poisson equations self - consistently within the thomas - fermi approximation @xcite, which implicitly assumes that the potential landscape varies slowly on the quantum mechanical length scales. in this work, we show that, by applying a current in the + y direction, it is possible to achieve equi - width incompressible strips ( iss ) on both sides of the sample, by using a certain imposed current. as a result, our self - consistent calculations show that the widthes of the Qhps also depend on the current direction, which is in strong contrast to the conventional approaches.
we present a general recipe for the description of quantum kinetic phenomena in quantum wires ( qw ) by using quantum kinetic equations ( qkes ) instead of the boltzmann equation ( be ).   the main effect of level broadening effects in qkes is that they allow scattering processes that are forbidden by energy and momentum conservation to be considered, and that are nonzero off the energy shell within some width defined by the interactions and the external fields. when there are small energy scales in the problem that are narrower than the quantum width of the state, such as narrow band - width laser excitations, these effects can be neglected, and the qkes can be presented in a form similar to the bes.the application of this recipe to the problem of hot luminescence from a quantum wire ( qwr ) due to electrons excited by a narrow band, noncoherent laser to the close vicinity of the threshold for optical lo phonon emission is discussed.
we report the discovery of a " r - h dropout " in the hubble deep field ( hdf ) test image of the near infrared camera and multi object spectrometer ( nicmos ) on board the Hubble space telescope ( hst ).   the object is a redshift elliptical galaxy with a very high formation redshift ( @xmath11 ), but its morphological characteristics are not well understood.    the morphology, the size and the colors strongly suggest the object to be an " old" elliptical galaxies ( or bulge - dominated object ) at @x Math6 and therefore with a low formation redshifts.. the light profile and the effective radius of the object are measured using the hst angular resolution and the luminosity profile is well described by an@xmath0 law. models with dust are considered to explain the extremely red colors, given the growing evidence for significant amounts of dust in high redshift galaxies.
the sensitivity of numerical solutions to the @xmath0-body problem to small changes in initial conditions and numerical errors has been an active area of research since miller s landmark study.   if numerical errors in numerical solutions cause such drastic changes in the actual positions and velocities of particles then how can we trust the dynamics that these solutions represent?   shadowing is a way of proving that a true solution to a dynamical system follows close to a numerical solution. here   we discuss the existence of shadow orbits for the gravitational 3-bodyproblem. first, definitions and concepts related to shadowing of dynamical systems will be introduced. next, a refinement procedure which makes corrections to numerical orbits to reduce the errors incurred at each time step will be presented. the sitnikov problem   will then be presented and used as a simple model to discuss escape and capture of orbits.. an approximate poincar map is then presented to model orbits of the sitkov problem and will be used in conjunction with the refinement procedure to discuss the validity of numerical answers by way of shadowing. finally, it will be demonstrated that the shadow times for this problem can be modeled as a poisson process.
the coherent scattering spectrum of a two - level system with permanent dipole moments ( pdm ) at multiphoton resonant excitation in the field of a moderately strong laser radiation is investigated.   it is shown that the study of this process is important for efficient population transfer, generation of moderately high harmonics, as well as for generation of low - frequency radiation, specifically, for realization of intense smoothly tunable terahertz radiation sources. based on the results of numerical calculations,   a simple analytic expression for the time - dependent mean dipole moment, taking into account the dynamic stark shifts, is obtained. in particular, based on this expression results, concerning the main spectral characteristics of considering process, are in good agreement with results of performed numerical calculations. the effect of compensation of dynamic stark shift on the radiation spectrum   is also discussed.
we have designed and placed into operation a ccd camera system optimized for high speed time - series measurements of oscillating white dwarf stars.   the camera is based on a commercial ccd chip with a 512@xmath1512 pixel array size and a readout rate of 3.05 pixels per arcsecond, and uses a thermoelectric cooling system that keeps the chip at -45c to keep the dark count of 12 adu / s in the chip smaller than the dark counts coming from the moonless sky ( ca. 37 adu/s ). as a result  , we can obtain data of better quality on fainter stars than the photomultiplier ( pmt ) instruments could measure, and are now in a position to compare and contrast these two approaches to the same measurements, and demonstrate where ccds are superior for this work and where they are not.
the motion of a brownian particle harmonically trapped in optical tweezers in a volume of a viscous fluid is usually modelled by the ornstein - uhlenbeck stochastic process @xcite.   bayesian inference provides a principled solution to this inverse problem, making optimal use of the information contained in the partially observed sample path. here  , we present two bayesian methods for estimating the trap stiffness and diffusion coefficient from time series containing a million points in less than a millisecond. using the markov property of the sample path,   the first method estimates the mean regression rate and the diffusion coefficient jointly and the second method extracts information from the equal - time fluctuations of the position, which, in equilibrium, can not depend on the friction coefficient.
we report the first measurement of genus curves for the two - dimensional mass map in the neighborhood of distant rich galaxy cluster ms1054 - 03, reconstructed from weak lensing data obtained by suprime - cam ( subaru prime focus camera ) on @xmath4 m subaru telescope @xcite.   we examine the non - gaussian feature in the measured genus curve by comparing it with a gaussian prediction, and demonstrate the feasibility of the method to examine the statistical properties of the large scale mass distributions in the universe.
the adiabaticity of the gross - pitaevskii equation ( gpe ) is a fundamental property of the mean - field description of bose - einstein condensates ( becs ), and its applicability to nonlinear systems is well established in the context of the superposition principle of quantum mechanics.   however, it is of interest to determine to what extent this principle carries over to _ nonlinear  quantum systems, such as becs, in the region where the means - field theory is appropriate. here, we develop a physically relevant one - dimensional bec model based on the gpe, which we study in detail by means of analytical and numerical methods to determine the nature of adiapaticity in nonlinear quantum systems within mean-field theory. using these methods  , we show that when the dynamical time scale of the system is the largest one in the problem, the adiabsorbable state of the hamiltonian evolves sufficiently slowly in time for the applicability of the theorem to be valid, the dynamics can be adiobasic, and the equilibrium eigenstates of the soliton solutions to the nonlinear schrdinger equation can be
the integral field spectrograph ( ifs ) is a new instrument that will be used to study extrasolar planets.   tests on the ifs instrument were held in january and february 2013 at the _ institut de planetologie et dastrophysique de grenoble _ ( ipag ) facility with the aim to validate functionality of the science and calibration templates and to preliminary estimate the performances of the instrument.the tests were performed both in the yj ( 0.95@xmath51.35 micron ) and in yh - mode using the appropriate combination of lyot coronagraph and apodized mask. data were then reduced exploiting the data reduction and handling ( drh ) software that allows to perform all the required calibrations and the speckle subtraction procedure through the spectral deconvolution ( sd ) method or angular differential imaging ( adi ). for both the modes appropriately combining sd and adi,   a contrast better than 10 @xmath1 can be obtained for both types of data. to further confirm this results we add a number of simulated planets to the raw data at different separations and with luminosity contrast of 10@x Math7 and 10
we use observations of type ii supernova ( sn ) light to study the impact of  decay on the photospheric phase emission.   we show that  is important in many sne, and constrain the effect that  has on the light curve shape. by using the time - weighted integrated bolometric light curve, we derive a measure of the cooling envelope emission alone ( i.e., the one that would have been observed if there were no radioactive decay ), which is directly related to its light curve form. for most types of sn,   the decay rate is not correlated with other sne properties such as the peak brightness or spectral features.
the physics of the early universe represents a challenge both theoretically and experimentally.   quarkonia suppression in medium has been considered a promising probe to study quark gluon - like particles ( qgp ) in heavy - ion collisions @xcite. here   we show how to reproduce the neutrino thermal width by using the eft techniques for non - relativistic majorana neutrinos and heavy quarkonium in a weakly interacting qgp using the leptogenesis formalism.
we investigate the existence of three - dimensional ( 3d ) hairy black holes solutions for theories based on torsion.   in particular, we consider a scalar field non - minimally coupled with the torsional scalar, with a self - interacting potential in teleparallel equivalent of general relativity ( tegr ), and we find three -dimensional asymptotically ads, hairy blackholes. to study the properties of these black holes, we perform a regularization procedure to ensure that the scalar fields are finite on the horizon. by doing so  , we show that the dark energy sector is attributed to both the minimal case and the nonminimal case. also, we find that the black - hole solution has a richer structure than the one found in the cosmological context.
weak gravitational lensing is a powerful tool for mapping the distribution of dark matter since it measures the matter distribution directly without the need to make assumptions about the way that light traces mass.   most approaches focus on shear, which is the first - order distortion of the background galaxy images caused by the bending of light from large scale structure ( lss ). recently, weak lensing techniques have been extended to include higher - order distortions of background galaxies to improve the constraints on the mass distribution on small scales. in @xcite,   the second - order effect in gravitational potential has been detected for the first time and the term  flexion " has been adopted to describe it. in this paper, we compare the ability of two different methods to reconstruct the projected mass distribution from the flexion measurements using the global shear inversion method. both methods show that they can reconstruct the convergence map from the measured shear field in the presence of noise. however, the latter method is better able to do so than the former because it takes into account the intrinsic ellipticity dispersion of the random shapes of galaxies.
we study the spectrum of self - adjoint extensions of the symmetric operator constructed from (  ).   we find that under exactly the same conditions there is a subfamily of self-adjoint extensions whose point spectrum is @xmath17. in this case, we use the theory of singular finite rank perturbations to study the renormalization procedure @xcite for the re - resolvent of the hamiltonian extension of the scalar product in the hilbert tensor product.
we have recently shown that the distribution of the diffusion coefficients of the time - averaged mean square displacement ( msd ) in the stored - energy - driven lvy flight ( sedlf ) is different from that in continuous - time random walk ( ctrw ).   this difference is due to the fact that a random walker can not move while it is traped in sedlf, whereas it can move with constant velocity in lvy walk. here  , we discuss the origin of this difference and discuss the implications of our results.
we present the results for na and o abundances obtained for 20 rgb stars in ngc 2808, observed during the flames science verification.   we show that na is anti - correlated with o, and we find preliminary evidence that in this cluster the o - depletion in some stars could be as extreme as in m 13 super - o - poor stars.
the bell labs south pole polarization telescope ( @xmath2w ) is a 16-element array comprised of twelve 90  ghz and four 40  Ghz correlation receivers.   the goal is to probe the polarization of the north celestial pole ( ncp ) using a new feed system designed to couple to the 7-meter crawford hill antenna to produce a 4@xmath0 beam that will be sensitive to the predicted peak in polarization for the ncp region.
we present a unified approach to the formalism used in the hermite polynomials for the edgeworth and gauss - hermite expansions of the probability density functions.   we use the example of the @xmath0 distribution for various degrees of freedom to illustrate the properties of gram - charlier expansions, and we find that they are both very efficient and reliable methods for measuring the deviations of a probability density function from the normal distribution.
a strange quark star ( sqs ) is a hypothetical type of exotic star composed of strange quarks.   it is theorized that when the degenerate neutron matter which makes up a neutron star is put under sufficient pressure due to the star s gravity, neutrons break down into their constituent up and down quarks ; some of these quarks may then become strange qu atoms and form strange matter, and hence a strange quink star.    the aim of the present work is calculating some properties of polarized sqs at finite temperature in the presence of a strong magnetic field using the mit bag model with a density dependent bag constant. to this aim, in section , we calculate the energy and equation of state of sqm in the absence of magnetic field at finite temperatures by mit bag models using a density independent bag constant.in section ,we solve the tov equation, and calculate structure of sqs. in section,We study the properties of strange qark matter and resulting equation of states.
the detection of x - ray emission from hot gas at large radii is limited primarily by its intrinsic low surface brightness, uncertainties associated with the subtraction of background ( and foreground ) emission, and the ability to remove contamination from compact sources unrelated to the cluster.   we report the detection of X - ray emissions from the most luminous cluster in the @xcite sample of clusters at @xmath5 selected from the _ bright cluster survey_ ( 1835  ), using three observations for a total of 193  ksec exposure time, extending the analysis of these _ chandra _  data performed by@xcite.,1835  has a redshift of @x math0, which for @x Math6  km  s@xmath7  mpc@x maths7, @xMath8, @Xmath9 cosmology corresponds to an angular - size distance of @exposure10  m pc, and a scale of 237.48 kpc per arcmin. due to its high luminosity and availability of deep   chandra  observations with local background, 1835 makes it ideal candidate to study its emission to the virial radius.
the dynamics of opinion formation in a multi - agent society has received growing attention in recent years, and the role of conviction has been introduced as a relevant parameter in a class of discrete opinion models.   it was shown in @xcite that beyond a certain value of this conviction parameter, the society reaches a consensus, where one of the two choices ( positive or negative ) provided to the individuals prevails, thereby spontaneously breaking a discrete symmetry. in this paper, we introduce a kinetic model for conviction formation, by assuming that the way in which conviction is formed is independent of the personal opinion.. then, the personal conviction parameter will enter into the microscopic binary interactions for opinion formation considered in @xaicite, to modify them in the compromise and self - thinking terms. within this picture, both the conviction and the opinion are modified in time in terms of microscopic interactions.    as we shall see by numerical investigation, the additional conviction variable is to bring the system towards a steady distribution in which there is formation of clusters even in absence of bounded confidence hypotheses.
the two - dimensional ferromagnetic xy model has had a long history of studies concerning the dynamics of spinwaves at low temperatures.   it was first analyzed in the harmonic approximation, and the divergence of the dynamic structure function at the spinwave frequency was found. here   we describe an alternative theoretical description in which the divergence does not occur. for very low temperatures,   any nonlinear effects should be very weak, do not lead to vortex production, and can be included as the damping or scattering of the spin wave modes, that results in a spinwave lifetime. using the feynmann diagram technique for finite temperatures, we calculate the spinaway damping by applying the leading diagrams to second order in the fourth - order hamiltonian, using the memory function formalism, combined with some input information from classical monte carlo data. when the temperature is reduced to the range of 0.5 to 2.0, the spinstroke damping is negligible, and no vortex production is observed.
we have developed a simple model for the evolution of the extragalactic background radiation field using a minimum number of parameters by fitting the emissivity predicted by the model to recent results of high - redshift galaxy surveys.   the intrinsic spectrum of mkn501 inferred from our model is in good agreement with theoretical predictions.
non - critical string theory @xcite provides a simple and tractable toy model to understand various aspects of string theory.   one of the fascinating formulation of the theory is given by the description with the matrix model. in this paper  , we try to give explicit answers to the following questions : how do critical points and potentials look like and what is the corresponding geometry appearing at the vicinity of critical points?   our results provide further insight into the relationship between the existence of critical point and the choice of hermiticity of critical potentials.
we investigate the role of the mean reverting behaviour of the electricity spot price in the pricing and hedging problem of european options on forwards.   we use an exponential model to model the delivery period of the underlying commodity and its effect on the option price.    we find that the impact of the speed of the means reversion of the spot prices varies depending on the length of the delivery periods and on the time since the exercise of the option. as the underlying forwards typically deliver the commodity over a period, one may expect that the effect of this mean reversion on theoption price averages out in the price of the forward price. however, if one or more of the factors are not taken into account, the effect is even more pronounced, and the pricing error is much larger. for this purpose, we consider a multi - factor spot price model consisting of one non - stationary process and a sum of independent ornstein - uhlenbeck processes. by fitting the model to the observed time series, we show that the results are in good agreement with the results of the literature.
the solution of the in - medium four - particle equation describing the modification of the binding energy of the @xmath0-particle in symmetric nuclear matter is reported.   an alt - grassberger - sandhas - type equation has been solved and the results will be compared with those of perturbation theory.
we present a theoretical approach to the study of proton - neutron ( pn ) knockout in the electromagnetic current operator @xcite.   the main features of the theoretical approach are outlined, with special emphasis on the treatment of the two - nucleon overlap function and the center - of - mass effects in the electromagnetically induced final state interaction operator @xmath0o(e, e@xmath1pn)@x Math2n and @x math0o@xMath2n reactions in different kinematics. for the exclusive process, where the residual nucleus is left in a discrete eigenstate of its hamiltonian, we study thoroughly the impact of the conceptual improvements performed in the past years by the pavia group on the analysis of the cross section of the effect of pn - knockout on the tensor correlations @xracite. under the assumption of a direct knock - out mechanism, we show that the results obtained from experimental data are consistent with the theoretical results. however, the influence of competing two - body mechanisms like meson - exchange currents, isobar - excitation or final state interactions ( fsi )
we present an online suffix tree - based algorithm for locating the most recent longest match of an arbitrary pattern of a string in @xmath1 time.   the algorithm is optimized for the special case of lempel - ziv factorization, where it is desirable to find the most recently occurrence of each factor of the factor in order to reduce the number of bits necessary for subsequent encoding.
optical phase estimation has many practical applications, such as metrology, optical communications, quantum communications, and quantum computation.   generally, the precision of phase estimation is limited by the standard quantum limit ( sql ) @xcite. to improve the precision with which these applications can be implemented,   it is important to generate strongly phase - squeezed light pulses with large coherent amplitudes, i.e., the high peak power. in this paper  , we propose a scheme to perform phase squeezing on coherent light pulses using quantum interference between two slightly phase - shifted coherent states followed by post - selection of the destructive interference. in order to verify the phase - squeezing effect, we calculated the maximum fidelity between the generated state and an arbitrary squeezed coherent state. here, we found that a @xmath19-db phase -squeezed state can be generated with a mean photon number per sec of @x math19 db at 1064 nm using a monolithic standing - wave lithium - niobate optical parametric amplifier.
deep neural networks have significantly improved the state of the art for a wide variety of machine - learning problems and applications.   unfortunately, these impressive gains in performance come only when massive amounts of labeled data are available for supervised training. since manual labeling of sufficient training data for diverse application domains on - the - fly should be prohibitive, there is strong incentive to establish effective algorithms to reduce the labeling consumption, typically by leveraging off-the - shelf labeled data from a different but related source domain that is big enough for training large - scale deep networks. however, this learning paradigm suffers from the shift in data distributions across different domains, which poses a major obstacle in adapting predictive models for the target task. here   we propose a novel residual transfer network ( rtn ) approach to domain adaptation in deep networks which can simultaneously learn adaptive classifiers and transferable features from labeled data in the source domain and unlabeleddata in the target domain by embedding the adaptations of both classifier and features in an end - to - end deep architecture.. extensive empirical evidence suggests that the proposed rtn approach outperforms state of art methods on standard domain adaptation benchmarks.
the lattice boltzmann method ( lbm ) is a mesoscopic simulation method that can be used to study microflows on the length scale of the lattice constant.   it has been shown that in the macroscopic limit, the navier stokes equations can be recovered from the lbe equations. however, when these models are applied to near - continuum flows, the slip boundary conditions must be perfectly specified to capture possible boundary effects on the flow behavior. in this paper  , we use a recently proposed velocity boundary condition for the Lbe that is independent of the relaxation process during collision and contains no artificial slip and thus simulate slip flows by the use of a parameter @xmath0 that defines the surface tendency to cause slip.. thus we study flow past surfaces on which the slip length is modulated in stripes.
according to the instanton liquid model ( ilm ) instantons are largely responsible for the spontaneous breaking of chiral symmetry and the low energy properties of light hadrons.   this has been demonstrated using phenomenological instanton liquids. in the present paper   i address the question of how to reconcile the insensitivity of light Hadrons to the string tension with the failure of the instantons alone to reproduce the correct physics ( found in @xcite ). along the way   I show that the optimised clover dirac operator introduced in@xcite performs much better in this respect than the wilson operator. by explicitly studying the zero mode zone in the simplest nontrivial case, that of an instanton antiinstanton pair,   it is found that the mixing of the two types of quark ( quasi)zero modes is not essential for the physical picture emerging from the ilm.
gdino@xmath4 is a rare earth indate compound with gd@x Math1 ion as the outermost orbital.   the magnetic ordering, the crystal structure and the possibility of spin and lattice coupling in this system have been investigated by means of rietveld refinement of low temperature x - ray diffraction ( xrd ) patterns, magnetostriction measurements and density functional theory ( dft ) calculations. among all the compounds in the rare - earth indates series, gdino @x math4 draws a special attention because of the presence of large in@x maths1 ion which has exact half - filled 4@xMath8 shell as the outsidemost orbital.the experimental results show that the system exhibits the negative thermal expansion ( nte ) over the temperature range between 50k and 100k. erythroidization of the crystalline gd @xcite at temperatures below 150k is attributed to the change in magnetic ordering due to the distortion in the non - centrosymmetric atomic structure of the system. while the mechanism of nte in crystalline Gd@xcite is associated with the changes in magnetic order, the same is not observed in gdinos
exoplanets are a large population of planets that allow models of planet formation and migration to be constrained.   however, the majority of known exoplanets orbit too closely to their host stars in order to be accessible to advanced imaging instruments, such as the gemini planet imager, which allows direct detection of thermal emission from long - period exoplanet transiting systems. while accurate exoplanetary masses are needed to characterize individual exoplanetry, the dominant exoplanetic - finding technique, radial velocity, is insensitive to stellar reflex motion in the plane of the sky, and therefore, measured mass is only a lower limit to the true mass because @xmath5 is the most probable value for the orbital inclination distribution. here  , we review the current state of the art in the use of transmission spectroscopy to detect scattered and emitted flux from exoplanetting systems, and we discuss how these techniques can be used to determine accurate ex Earth masses for non - transiting ex orbiting stars.    we also discuss the potential of using transmission spectra from transiting system observations to determine the mass of non - transit exoplanettes, and show that the method is applicable to the study of hot jup
physical layer security is an alternative to the traditional upper - layer cryptographic techniques using secret keys. in @xcite, it is assumed that the channel state information ( csi ) from the eavesdropper is perfectly or statistically known at the source.   this assumption, however, is unlikely to be valid in practice, especially when the eaves dropper is not an authorized component of the communication system. in this paper   we propose a location - based beamforming scheme for wiretap channels that does not require any form of csi be passed by the eavesdrop back to the source.we consider a wiretap channel with rician fading, where alice and bob are equipped with uniform linear arrays ( ula ) with @xmath1 and@xmath2 antennas, respectively, while bob is equipped with a single antenna. as such, the locations of alice, bob, and eve are denoted by @x Math3, @x maths4, and @x math5, respectively.    we consider that the main channel between alice & bob and the eavesdropping channel between Alice and eve can be used to beamform the mainchannel and the wiretap Channel. 	 we find that the
a double exchange model for the motion of conduction electrons in the background of core spins is introduced in @xcite.   the model describes the interaction between core spins induced by a single conduction electron and the spin of an electron at the same lattice site. here   we consider the model in the limit of a very strong hund s interaction between two core spins and of very large core spins. to specify the model completely we have to fix the total number of conlation sites in the sample ( filling factor @xmath9, where @x Math10 is the number of sites of the lattice ). using this formula we derive the berry phase for a single spin using a fermionic determinant representation for the kinetic part of the action. as a result   it is shown that the effective action for core spins can be written as a function of the total spin operator on a given site which is either an integer or a fractional one.. however, the ambiguity of the berytheoretic phase for fractional spins raises the question of what one means by a “ fractional spin”.    we show how the ambiguity depends on the fact that the total
we extend the result of ref.   @xcite for light - light and heavy - light mesons by considering the presence of quarks with finite masses and the introduction of a coulomb - like interaction and constant potential in addition to the confinement. in the limit of small masses and small strength of the short range potential, or in the limits of large angular momentum,   all calculations can be worked out analytically.
non - gaussian nonclassical states of light have been used experimentally to perform continuous variable teleportation of a schroedinger s cat state generated with the photon - subtraction protocol @xcite.   the quality of the teleportation is high enough that the output teleported state is also a non - classical state of light with a negative wigner function. in this paper  , we present a theoretical model for the case of non - gaussian non - classical quantum states using the heisenberg picture as an input state and show that it is possible to predict the success of teleportation in a way similar to the recent experimental results of@xcite by considering the temporal properties of the input state from the point of view of quantum field fluctuations.
supernova ( sn ) light curves are one of the major sources of information about the nature of these events.   they infer structures of the stellar progenitors and reflect the underlying energy sources created in the explosion. here   we report our initial results of the intermediate - band sn photometry program using a unique photometric system, also dubbed the batc system, which is designed to cover the wavelength range 3300 @xmath1- 1@xmath2 m. we have been engaged in systematic optical monitoring of bright thermonuclear supernovae ( sne ia ) in nearby galaxies ( z@x Math00.01 ) by using several batc filters near maximum light in several passbands. among the five sn ia observed so far, sn 2003cg was found to be the most intrinsically subluminous event because it has a shoulder or secondary peak that is missing from its light curves in i and k bands.    the secondary peak feature was observed in batc s redder light curves but not in the other sn ias.
many - electron atom is usually considered as many - body problem and is described by the wave function constructed from the wave functions of one electron, moving in the central nuclear charge field and in the screening field of the remaining electrons.   it is necessary to account for relativistic and correlation effects in order to obtain accurate values of atomic quantities. in this paper   we present a new method for calculating the non - relativity hamiltonian of many - electron atoms and their ionization degrees based on the breit - pauli approach using the spin - spin - contact term and the orbit - orbit interaction as two - particle operators.
massive stellar clusters are rare, distant and often obscured by surrounding gas and dust.   however, they are important tools for understanding the evolution and feedback from massive stars in the milky way. here   we review the current state of the art in the search for massive star forming regions in the Milky Way using a series of recent and future optical and near - infrared surveys including the vista variables in the va lctea ( vvv, borissova et al., 2003 ) and the two micron all sky survey ( 2mass, dutra & bica 2000, 2001, froebrich et al., 2007 ). with the advent of new facilities such as gaia, jwst, alma, ska, this field will benefit greatly from the detection of new objects and the characterization of the identified cases.
we study the effects of rotation on the radiation driven winds of early - type supergiants.   we focus on the explanation for the occurrence of disks around fast rotating bsupergiants, i.e. a dense disk of outflowing material in a fast line driven wind to explain the observed characteristics of the spectra of these stars. using the rotationally induced bi - stability model ( rib - model ) of lamers & pauldrach   ( @xcite ), we find an increase in the mass flux from the equator and a decrease in the equatorial wind velocity compared to the poles for rapidly rotating b(e ) supergiant stars with effective temperatures between 20  000 and 30  000 k. we also find that the rotational terms in the equation of motion can be modified to account for the effect of gravity darkening and oblateness on the shape of the star.
lutetium ( lu ) is the last element in the lanthanide group and has a rather simple spectrum compared to most other lanthanides.   the first rydberg series of lu ionic states converging to the ionization potential ( ip ) were determined by laser resonance ionization spectroscopy ( ris ) in 1989. in this work  , we applied ris to study the even - parity rydburg series of Lu @xmath0@xmath1, @x Math0 @x math2 and @x maths3 @xMath4, which converge to the ip.. the results are compared with the literature and the level energies of 104 new states are reported.    furthermore six new even - para - parity ai series converging into lu ions are also reported. for each of these states, the configuration of the ai states has been assigned with the aid of rmct theoretical calculations.
in the brightest radio galaxies, hotspots at the ends of the radio jets are often found which radiate from radio to x - rays.   these are formed where the jet interacts with the ambient medium and decelerates abruptly, forming a double shock structure. in cyga,   the jets form primary hotspots b and e and secondary hotspots a and d in the western and eastern lobes, respectively, as designated by hargrave & ryle ( 1974 ). for some of these hotspots, the x - ray emission is consistent with production by the synchrotron self - compton process ( ssc ), but the origin of the kev photons from the hotspots can not be explained in terms of a ssc model. here  , we review the current understanding of the mechanism of the hot spot emission from cyga's radio jets, focusing on the role of the magnetic field strength in the formation of the hotspot emission.
we report the first detailed spectroscopic determination of the photospheric properties of two recently discovered transiting planet systems, @xcite and @xmath16100 pixel@xmath18.   we use the constraint on the stellar density that comes directly from the transit light curves to derive more accurate values for the mass and radius of the parent stars, and we also perform a reanalysis of existing photometry utilizing a technique which treats stellar limb darkening using adjustable parameters. in both systems,   the effective temperature and metallicity determinations are improved over those reported in the discovery papers, and the radial - velocity and photometric observations of the two systems are refined.
this paper addresses a theoretical problem arising in a novel approach to network traffic measurement the authors and their collaborators have recently developed.   the authors present a novel counter architecture, called " counter braids ", which is fast, very efficient with memory usage and gives an accurate measurement of _ all  flow sizes, not just the elephants. under a probabilistic model for the flow sizes ( namely that they form a vector of iid random variables ),   counter brabs achieve a compression rate equal to the entropy of the flow size distribution, in the large system limit. using this method, we prove that for any rate larger than the flow entropy, the flows can be recovered from the counter values, with error probability vanishing in the big system limit.graphical abstract
the interplanetary magnetic field ( imf ) is formed as a result of the transport of the photospheric magnetic field by the solar wind flowing continuously from the sun.   the imf is organized into large regions of opposite polarity separated by the neutral sheet, which is wavy and is inclined to the plane of the ecliptic. in the present study, we used the tibet - i air shower array to explore the magnetic field of the sun s south polar region at the radial distance of about 2.3 au from the Sun being at near solar minimum activity. during the study  , we found that the radial component of the solar magnetic field was independent of latitude, that is, the dipolar pattern of the field strength is not reflected in the heliosphericagnetic magnetic field. on the other hand, the direction of the rotation of the corona hole was more strongly related to the solar activity cycle than the radial components of the magnetic fields.
radio continuum emission from normal galaxies arises from a combination of non - thermal ( synchrotron ) and thermal ( free - free ) processes.   the former critically depends on a galaxy s magnetic field and cosmic ray ( cr ) electron distributions, while the latter relies on the formation of star - forming regions that emit photons that are re - radiated by dust grains at far - infrared ( fir ) wavelengths. in this letter   we explore how star formation activity affects the relative spatial distributions of fir and radio continuum emission for a sample of 12 spiral galaxies observed as part of the _ spitzer _ infrared nearby galaxies survey ( sings ) legacy science project @xcite and the westerbork synthesis radio telescope ( wsrt)-sings radio continuum survey. to date, the evolution of crs has been studied directly only in the milky way, without providing any information regarding the initial source distribution or propagation history. using these data, we show that star formation rates ( sfrs ) vary by a factor of about 1.5  kcal / mol at 24  kpc within the largest magellanic cloud ( lmc ) and by an order of magnitude at 70  k pc within the second largest
we study the role of large - scale ( organized ) magnetic fields on the properties of motion near a rotating black hole.   we assume that the magnetic field arises from currents flowing far out in the accretion disk of the black hole, and that it arises from the formation of ordered bundles of the magnetic lines of force with a significant degree of long - range coherence. using general - relativistic magnetohydrodynamic simulations, we investigate the effects of organized magnetic fields in a different context of particle motion near weakly - magnetized black holes. as a matter of principle  , we want to understand under what condition chaos emerges and drives the particles motion near magnetizedblack holes.. we address the problem of regularity versus chaoticity of the resulting motion of electrically charged particles ( electrons and ions ) resulting from the mutual interplay of gravitational, electromagnetic, and gravito - magnetic effects of general relativity.
the interpretation of the high energy neutron scattering spectra of the cuprate superconductors ( cuprates ) has been a matter of debate.   it has been suggested that the observed high energy magnetic excitations in the cuprates may be due to the quantum excitations of spin stripes, which are unidirectional modulation in an otherwise antiferromagnetic texture. here   we show that at @xmath10, satellite peaks for even the most extreme case of square - wave spin stripes have very low intensity, and also that spin wave cones are rarely observed in the low energy regime. instead, the intensity can be gathered on the inner branch of the spin wave cone, or on the outer branch, depending upon the relative strength of the effective spin coupling across the charge stripes. by renormalizing the exchange integral using a parametrized heisenberg model  , we find that the spin polarization of the antiphase domain walls is strongly influenced by the spin degrees of freedom of the charge component, and that the effect of the interaction between the spin stripes is more pronounced at higher energies than at lower energies.
the judidt  @xcite readout system was developed for the small angle neutron scattering ( sans ) diffractometer kws1 at the previously active research reactor frj-2 of the forschungszentrum jlich, germany.   the system was then modified for a later use at the kws2 experiment at frm - ii. within the fp7/nmi3 @xcite european - founded project   it was proposed to use the Judidt readout electronics for the data acquisition of a novel anger camera prototype  @xxcite, being able to cope with counting rates of several hundred kilohertz. in this paper the results of the characterization of the stand - alone electronics are presented and commented. in addition, the data acquired with the entire system detector plus thejudidtReadout system is described and the corresponding results discussed.
the microbunching instability of a thermal electron beam in an accelerator is studied in the space without acceleration using the vlasov and poisson equations and the klimontovich distribution.   the oscillation of the electric field due to the density perturbation is derived by combining the solution of the initial - value problem and the poisson equation  @xcite together, and the amplitude of the energy modulation driven by the lsc impedance with and without the plasma effect is computed for a typical linac lattice starting from the exit of the electron gun and ending before the bunch compressor. at low energies that the quasilaminar approximation does not hold very well, the results show that the difference between the energy modulations calculated by the different methods develops rapidly at low temperatures and becomes very large before the whole bunch compressor, and leads to the noticeable change to the gain of the instability.
the acer ( _ activation  construction  execution  reflection _ ) framework is a network analytic framework that bridges the gap between prescriptive problem solving and knowledge - in - pieces.   we use the acer framework to investigate how upper - division students written work shows their mathematical thinking on typical homework problems. using data from a traditional undergraduate classical mechanics class, we find that students often fail to use the proper mathematical tools when solving homework problems because they are not explicitly taught to do so. within each of these four components, students perform multiple specific actions that are then detailed using sub - codes. within construction, students choose a coordinate system or set the limits of integration. within execution, students select among known mathematical tools such as evaluating integrals, using differential equations, or choosing appropriate coordinate systems. by using network analytic methods, we show that students use the correct mathematical tools to solve homework problems in a traditional course.
the absolute mass scale of the neutrinos is a great challenge in experimental particle physics.   the present work provides an analysis of the influence of the dark energy ( de ) model on the upper bound of the total neutrino mass, i.e. @xmath31 ev ( @x Math32 ), using the dataset _   tt, te, ee+lowp+bao and the base@xmath3cdm model. for the most simplest de model, which is the most commonly used to explain the observed accelerating expansion of the universe, the equation of state ( eos ) of the de component is = 0.1 + 1.0, where de is the dynamical de model with a free ( but constant ) eos parameter. by taking into consideration the different types of neutrines, we find that the nh hierarchy is slightly favored than the ih hierarchy, and the difference between the two hierarchies is smaller than that between the normal and inverted hierarchies. however, the differences between the three hierarchies are not very small, and they are not sensitive to the squared mass differences of each of the three masses. when considering the interaction between the neut
we study the low - frequency oscillations of a typical @xmath0-doradus star.   we show that dealing with rotation by the means of a second - order perturbative theory is not correct for rotation periods less than 3 days. using the same geometric formalism as above ( i.e. calculations of orbits of characteristics ) allows us to compute the frequencies of oscillations in the rapid rotation rgime.
the na49 experiment at the cern sps has measured the final distributions of strange hadrons from pb+pb collisions at different centralities in the range @xmath0 = 6.3 - 17.3 gev.   the results show that the strangeness enhancement factor for quark gluon plasma ( qgp ) production is enhanced in collisions with qgp production in comparison to those without qgp and could thus serve as a unique signature of the quarkgluon plasmas. this enhancement can be quantified by the ratio of yields in nucleus+nucleus to p+p collisions where the system is very small and the qgp creation is not expected.
the universe is assumed to be statistically isotropic at large scales in the standard model of cosmology.   recently, however, several evidences appeared for possible deviations from the statistical isotropy of the cmb temperature fluctuations. by the " power tensor " technique, we study the correlations between two multipoles and obtain eigenvectors with the maximum eigenvalue of the correlation matrix of two power tensors. using the randers  finsler spacetime as a special case, we find that the quadrupole  octopole alignment of cmb anisotropy is of about @xmath1. based on the one - year wmap data,   the probability of this alignment is expected to be much smaller than that of the planck 2013 results. in this paper, we propose an anisotropic inflation model in theranders spacetime to study the dipole modulation of the central microwave magnetic field ( cmb ) temperature fluctuations while there is a misalignment between the quadrant and octagonally oriented orientations by an amount between@xmath2 and @x math3.    the deviations from isotropy may be related with a privileged axis in the universe.
we develop a basic analytical theory for the gate electrostatics and the quantum capacitance of the graphene nanoribbons ( gn@xcite ).   we complement this analytical theory by exact self - consistent numerical calculations based on the tight - binding @xmath0-orbital hamiltonian within the hartree approximation. in order to understand the origin of the discrepancies between the analytical theory and the experimental results  , we relate the above discrepancy to the inability of the simple electrostatic model to capture the classical gate electrophysiological properties of the gated gn. the results of the analytical and numerical calculations are compared and discussed.
melanin is a biological pigment found in the skin, hair and eyes of many species, including humans.   it is thought to be a photoprotectant, but paradoxically has also been implicated in the chain of events that lead to melanoma skin cancer. as a result,   the origin of the broadband absorption spectrum of eumelanin has long been the topic of scientific debate. here   we review the current state of knowledge on the role of optical scattering in this process, and discuss the recent advances in the field.
counterfactuals are things that might have happened, although they did not.   the idea of the ifm has been applied to " counterfactual computation " @xcite, a setup in which one particular outcome of a computation becomes known in spite of the fact that the computer did not run the algorithm. recently  , this idea has been used for performing " counter Factual communication " @xaicite, which supposedly allowed to send information from bob to alice without transferring any particle between them. here   i discuss this issue in more detail and try to resolve the controversy.
the tunneling magnetoresistance ( tmr ) ratio of ga@xmath1mn@x Math2as/(gaas or alas ) heterostructures at 0.39 k in a mixed ferromagnetic and nonmagnetic tunnel junction ( mtj ) using diluted magnetic semiconductors ( dmss ) has been investigated.   the tmr ratio of the ga+/gaas+/ alas / gaas heterostructure was found to be more than 70% at 8 k in the absence of any applied bias @xcite, which is due to the high spin polarization of the dms electrodes and the high quality of sample and interfaces between gamnas and gaas layer. for the presence of an insulator layer,   it is possible to obtain a tmr ratios of up to 80% at 10 k with a cure temperature of 0.5 k. the results of the present study suggest that the effect of the interlayer exchange interaction between gaas and ga as well as gaas intermediary layer on the spin - polarized transport of electrons in the semiconducting band can be explained by the strong hund coupling between the itinerant holes in the valence band of gaas from
the current concordance @xmath0cdm cosmological model of the universe is the preferred model based on statistical selection criteria.   this model fits rather well the observational data and requires the minimum set of Cosmological parameters, but it suffers from the so - called coincidence problem ( i.e., why are the densities of cold dark matter and dark energy of the same order precisely today? " ). in this paper  , we show how to derive the matter power spectrum of a generic dark energy ( de ) model without the need of solving the perturbation equations for the radiation and matter components. by taking into account several observables such as the fluctuation of the matter density perturbations on a sphere of radius and the peculiar velocity of matter on spheres of radius, the weak lensing convergence spectrum and the cross - correlation of the sachs - wolfe ( sw and isw ) components of the cosmic microwave background ( cmb ) temperature anisotropies, the proposed model can be used to constrain the model beyond the expansion rate.
the relational data base model, introduced by codd in  @xcite, has been particularly successful since it is a mathematically elegant model well suited to describe almost all " real world " situations.   since the query languages associated to such model have a formal and simple definition, an interesting field of research is to study the expressive power of such language. in this paper   we introduce a new syntactic characterization of queries that are computable in a given data base based on the notion of partitions of the domain, where each partition represents a level of undifferentiation among objects, values or vertices. using this notion  , we give two new characterizations of relations expressible in a relational database : ( 1 ) a binary relation over sets of data values is defined, denoted by @xmath3, which relates those sets of information that can be extracted from the data base and ( 2 ) an automorphism, which describes the set of permutations over the elements of@xmath1 which produce a data base isomorphic to @x math1, which can be used to compute the same set of relations as @x Math0. these results are applied to a simple graph - based model
fundamental galaxy properties such as star formation history, morphology and gas content vary in a systematic way from dense environments like clusters of galaxies to low density regions in the general field.   it has long been known that there are systematic variations of these properties with the global properties of clusters, but it is still unclear to what extent the differences in galaxy properties in various types of clusters are due to the fact that the average local environment varies as a function of the cluster type. in this talk   we present the case of a cluster - related cluster with a very high star formation activity, which is strongly correlated with the presence of an irregular substructure, i.e. a cluster of early - type galaxies, and show that the fraction of spiral galaxies in the cluster decreases rapidly with increasing x - ray luminosity. at the same time, the proportion of elliptical galaxies within the cluster increases with increasing optical luminosity, suggesting that the cluster is more likely to be dominated by s0s than by s1s. on the other hand,   the distribution of the number of compact galaxies in each cluster is also known to be different depending on the size and shape of the substructures that are present inside the cluster
we analyze properties of a simple superradiance model interpolating between the familiar dicke and tavis - cummings hamiltonians.   the model shows a thermal phase transition, analyzed and discussed in refs.@xcite, as well as a zero - temperature ( ground - state ) quantum phase transition ( qpt ), which was realized experimentally with the aid of a superfluid gas in a cavity @xcite. here   we show that an unmistakable characterization of phases involving excited states is not achieved through the expectation values alone but rather through their different smoothed energy dependences ( trends).the main emphasis of our analysis is nevertheless put on the entanglement properties of excited states across the whole spectrum and their potential links to esqpts and quantum phases of the model.
the network and the ideas that flow through the network are inseparable and evolve together.   past events, stored in people s interest memories and the network structure, also affect future events. however, how this memory integrates with social dynamics and what role history plays in the process is still unclear. here   we investigate in a simple model how information about ideas is stored in the network and how information About the network is stored on the ideas. to investigate how much people s ideas can be recovered from the network topology and how much of the interaction pattern can be extracted from people s interests, we use a novel model of group formation in a co - evolving network where people s interactions influence the networks structure and vice versa. by comparing the results of our study with those of previous studies, we show that the network structures and ideas are integrated in the memory of the system, and that the relationship between the two processes is more complex than previously thought.
an extensive study of the reactivity of the transition - metal carbide and nitride ( tmx ) surfaces is being performed with the density - functional theory ( dft ).   it is aimed at an understanding of reactivity from fundamental principles, similar to the one available today for pure metal surfaces. due to the intimate relation between bulk and surface electronic structures, a careful mapping of trends in the bulk electronic structure is essential for the overall purpose to understand the trends in reactivity.the main electronic - structure properties are related to ( i ) the direction and amount of charge transfer between the tm and x atoms, responsible for the ionicity of the material, and ( ii ) the modifying effect on the metal _ d _ band upon the carbide / nitride formation, responsiblefor the formation of hybridized bonding and antibonding @xmath0 states.the key bulk properties are calculated, compared with earlier studies, and analyzed on the basis of the obtained knowledge of the electronic structure.
the galactic center ( gc ) is a promising region in which to search for highly variable and transient radio sources.   we have used recent advances in low - frequency and 3-dimensional imaging to produce a wide - field image ( @xmath3 ) of the gc, with uniform and high resolution across the field, from 0.33  ghz vla observations made between  1986 and  1989 ( @xcite ). here  , we report the detection of a new transient radio source, gcrt  j1746@xmath02757, and also report additional measurements of the radio counterpart to the x - ray counterpart to this source, xte  j1848@x Math0288.    the observations that led to the discovery of these two sources are described in detail, and we discuss what constraints we can put on them from our observations.
we have used the starburst99 code to synthesize the spectral energy distribution ( sed ) of the ionizing population of three giant extragalactic hii regions ( gehr ).   the synthesized sed corresponding to the corresponding ionizing clusters do not reproduce the observed emission line spectrum ( els ) ; they result too hard. in this case  , the intesity and equivalent widths of the wr features are underpredicted by factors of about 15 and 25 respectively. a number of possible causes for this discrepancy are discussed.
decoherence is the main limiting factor for quantum information processing.   we have previously shown that decoherence can be inhibited by subjecting a system to a sequence of very frequent pulses designed in such a way that their effect is equivalent to the application of the parity operator on the system. here  , we show that this method is also possible to harness the decohesion of the center - of - mass motion in ion traps.
the transit ephemeris refinement and monitoring survey ( terms ) is a project to refine and monitor known radial velocity ( rv ) planets at predicted transit times, particularly those planets in relatively eccentric orbits.   we describe techniques for refining ephemerides and performing follow - up observations using data acquired with the t10 0.8 m automated photoelectric telescope ( apt ) and lick rv spectrometer. through selective observations at optimal times, we produce viable targets for photometric follow - ups.
a dual - demodulator continuous time frequency modulation ( dd - ctfm ) system is a new technique for the measurement of difference frequency signals.   the aim of this paper is to review the basic principle of dd-ctfm technique and to discuss the issues in obtaining higher range resolution using dd -ctfm.    the problem of blind time limits the observation time and hence the range resolution in @xcite, which makes the claim of gough et al@xcite to be incorrect which states that " we have managed to eliminate the blind time associated with conventional c tffm sonars, thus making the output truly continuous"  . the phase mismatch problem in the output signal can be solved by using a local oscillator in the second channel of the receiver to extend the transmitted signal by a duration equal to the maximum blind time leading to high resolution in frequency and hence range.
euvej211558.6 (  ) is a magnetic cataclysmic variable star that was detected during the rosat all - sky survey in 1996 with a countrate of 0.05 cts s@xmath8.   we present here the combined results of our optical observations obtained over a 70-day basis from south africa and chile, including 21 low - resolution spectra of this star and one with intermediate resolution ( 3  fwhm, integration time 600 sec ), obtained with the efosc2 spectrograph at the eso / mpg 2.2m - telescope on october 23, 1996, between ut 0:19 and 3:30. for the first time  , we show that the x - ray spectrum of  can be fitted using a single bremsstrahlung component ( @xmath18kev, 1 kev of 2 photons ) with x - rays spectral flux at 1 Kev of two photons @x math19 s@Xmath8 kev@x Math8. folded over the most likely optical period, the x -- ray light curve shows a clear on / off behaviour with length of the bright phase extending for
the modularity @xmath0 of a network is a measure of the modularity of the network.   it describes the property of many networks that nodes divide into modules with dense connections between the members of each module and sparser connections between modules. in order to understand complex networks,   we need to develop new measures that capture the community structure of a given network. here  , we review the current state of the art in the field of identifying communities in a network. using this measure, we show that the probability of a link existing between two nodes is proportional to the degree of the two nodes in question. for example, if the degree distributions of real networks are often far from random, the choice of@xmath23 is sensible ; this model implies that the proportion of links existing between node(s ) in a community depends on the degree distribution of the other nodes in the network ( e.g., the number of nodes in each module ).
the scanning near - field optical microscope ( snom ) is a powerful tool for studying the sub - wavelength details of objects in the near field.   it can be used to probe the surface of dielectric and metal objects at wavelengths smaller than the wavelength of the light they are using, such as about @xmath0. here   we review the current state of the art in the theory of the snom and present a new approach to solving the problem of the electromagnetic scattering between tip and surface which is needed for a realistic description of the tip.. the method is based on a co - ordinate system which uses a real space discretisation to simulate the shape of the edge of an optical fibre tip scanned over a range of different objects. by taking into account the fact that the tip itself is a cone or paraboloid shape with a smooth surface,   the technique is able to reproduce the image produced by a snom which is capable of scanning over a wide range of objects with a diameter of about 20 - 500 nm. however, this method is limited by the need to use a regular, cartesian grid to represent both the tip and the object, which is not possible with the
we report on extensions to previous work on dynamical cavity qed effects in the photon statistics of transmitted light from a driven optical cavity coupled to an ensemble of two level atoms.   the system under investigation is an extension of the jaynes - cummings hamiltonian which includes effects of atomic and cavity field decay as well as a coherent driving field, and the coupling between the cavity field and atoms has a significant effect on the evolution of the system, in particular in the strong coupling regime where a single quantum of energy and hence single quantum fluctuations give rise to nontrivial dynamics. here   we show that nonclassical correlations in photon statistics which violate a schwarz inequality have been predicted for this system, including photon antibunching and sub - poissonian statistics, and also overshoots and undershoots. however, the theory matches the experiments in terms of qualitative behavior while the quantitative size of the non classical effect does not. in order to explain this discrepancy we consider complications in the experiments which may be responsible for the discrepancy including deviations from the weak field limit and dephasing due to atomic traversal of the cavity. by solving the master equation for the system and by quantum trajectory
the framework of supersymmetry ( susy ) for explaining the flavor structure of fermion masses and mixings is being challenged by the discovery of a higgs boson  @xcite and the lack of evidence for beyond the standard model physics.   we consider a class of models that attempt to explain this flavor structure. within these models,   the typical hierarchy between fermions of adjacent generations is roughly a loop factor ( with variations among models ), in qualitative agreement with the observed spectra. as a unique extension of the space - time symmetries of the s - matrix in four dimensions  , susy is well motivated at high scales, irrespective of its relevance for setting the electro - weak scale. using susy as a guiding principle for the particles and interactions that mediate flavor violation, we find that introducing susy at a high scale ( a pev or above ) automatically includes all of the necessary ingredients to mediate flavour violation from the third generation fermons to those of the first and second families.
we calculate the wrapping probability @xmath0 in the two - dimensional problem of percolation on a klein bottle and compare it with the results of the known calculation of per colation on the torus.   the monte carlo calculations were performed on square systems of various sizes with the newman   ziff algorithm. to this end, we use the _ union find with path compression _ algorithm for the joining of disks into clusters and the linear dependence on the number of objects is reached owing to the use of the_ union find by path compression   algorithm for its joining of clusters. as a result, the wrapping probabilities of the system are found to coincide with each other, whereas the scaling exponents of the quantities @x Math0 and @x math1 are significantly different.. the last circumstance can be due to the degeneracy of the percolating cluster on one or both surfaces.
the center of our galaxy is at @xmath11 kpc ( reid 1993 ).   the hipparcos catalogue of parallaxes will improve this distance measurement. in this paper   we present an estimate based on the comparison between the absolute magnitudes of the red clump giants measured by Hipparcos and by ogle ( optical gravitational lensing experiment, cf. udalski et al.,   1997 ). these stars are the metal rich equivalent of the better known horizontal branch stars, and theoretical models predict that their absolute luminosity only weakly depends on their age and chemical composition. to reduce the systematic error of the galactocentric distance determination, we compare the absolute magnitude of the nearby red clumps with accurate ( better than 10% ) trigonometric par allaxes measured by hippARCos with the apparent magnitudes obtained by the ogile in baade s window using the color - magnitude diagram of the same region. for each star, we determine the variance in the absolute i band magnitude to be only@xmath12 mag.. the difference between the values of the two groups of stars is less than 1.5 kpc.
in the 1970s it was recognised that the @xmath3-nucleus interaction near threshold in kaonic atoms is determined by the pion - nucleon scattering amplitude at subthreshold energies.   an algorithm devised to account for this energy dependence has been employed in extensive calculations using several models for strongly - bound @x maths3 mesons in nuclei and for strongly binding @x math5 mesons with a single in - medium nucleon. here   we revisit pionic atoms, a subject of which gerry brown made significant contributions in the early 1970s. based on global fits to pionic atom data, we present the model behind the algorithm for evaluating the subth thresholds of the@xmath0-molecular strong - interaction potential in the medium and the results of tests on the relationship between the proposed algorithm and experimental data are presented. as expected, the results show that the algorithm is sensitive to the presence of resonances near threshold but not to the nature of the interactions. however, the validation of the algorithm does not prove sufficient to confirm the validity of the approach. instead  , we discuss the role of the'minimal substitution'requirement'in the calculation of the @
quantum entanglement is the basis for quantum information and quantum computing.   spontaneous parametric down conversion ( spdc ), the generation of two lower - frequency photons when a pump field interacts with a nonlinear crystal, has been shown to be a reliable source of photons which are entangled in their orbital angular momentum ( oam ). here  , we calculate the exact analytical form of the biphotons for any laguerre - gauss pump, with no restrictions on the angular or radial momenta, @xmath0 and @x Math1, respectively, or, in particular, on the width,@xmath2, of the pump, signal and idler modes. using our results, we show that oam is conserved and that the coincidence amplitudes of the lg modes in the generated two - photon entangled state for a variety of pump beams are found to be in excellent agreement with previous analyses. by allowing the beam widths to be free parameters, we also show that the pump to signal / idler size plays a critical role in the engineering of the down - converted state, with states only being maximally entangled at particular width ratios.
the screw - boundary condition provides a flexible scheme to construct a finite cluster from an arbitrary number of spins @xmath0. with the aid of novotny s method @xcite,   one is able to implement this condition systematically.   the simulation results exhibit bumpy finite - size deviations depending on the condition whether the screw pitch@xmath10 is close to an integral number or not. in this paper  , we make an attempt to reduce the corrections inherent in the screw-boundary condition. as a demonstration, we adapt this idea to the ( ferromagnetic ) transverse - field ising model on the triangular lattice for @x Math5 and compare the numerical results with those of the fixed screw pitch @x math12. by tuning the spatial anisotropy and the biquadratic interaction, we are able to realize the deconfined criticality between the resonating - valence - bond and magnetic phases.
the spectra of brown dwarfs and extrasolar planets show emission at high energies that can not be explained by quiescent x - ray emission or magnetic field coupling.   the presence of this emission indicates an ionised atmosphere, but the cause of this ionisation is unknown. in this paper  , we argue that the reason for this emission may be due to rapid ionisation of dust particles in the dusty gases of extrasolar atmospheres. assuming that dust grains can be charged for long enough for avalanches to occur, then they may be capable of providing local and intermittent ionisation. if so, they may also be able to provide a low level of magnetic field coupled emission, or only intermittent coupling, leading to occasional flaring.
we investigate the solutions of the dirac equation for a fermion of rest mass @xmath3 in the background of a smooth step potential, termed kink - like potential just because it approaches a nonzero constant value.   the problem is mapped into an exactly solvable sturm - liouville problem of a schrdinger - like equation with an effective rosen - morse potential which has been applied in discussing polyatomic molecular vibrational states @xcite and relativistic@xcite-@xaite contexts. by using tabulated properties of the hypergeometric function, we show that the spectrum consists of a finite set of bound - state solutions. as one approaches the conditions for the realization of spin and pseudospin symmetries, all of those bound -State solutions disappear asymptotically. however, bounded solutions do exist only under strict conditions.
tunnel fets ( tfets ) are strong candidates for future electronics applications due to their promise of low power consumption originating from their subthreshold - swing ( ss ) being less than the conventional limit of 60 mv / dec @xcite.   however, tfets usually suffer from lower on - currents if compared to ultra - scaled mosfets@xcite, since their currents are the result of the tunneling process. to overcome the low on - current challenge, two obvious solutions are : 1 ) increasing the electric field at the tunnel junction, or 2 ) decreasing the band gap and effective mass of the channel material. in this work,   a new method for increasing the Electric Field at the Tunnel Junction is proposed. using a low - k dielectric next to high -k dielectrics   can, in principle, increase the electrical field in homo - junction tfets significantly.
we present a new method for the calculation of the transmission and reflection amplitudes of bloch waves through a single barrier.   we use the band structure and wave function of a periodic superlattice to calculate the transmission coefficient @xmath0 from the electronic structure of an arbitrary barrier and two semi - infinite leads of the material separated by a barrier, e.g. @xcite. in this way   the problem is treated as quasi 1-dimensional and the transmission coefficients are calculated using the screened korringa - kohn - rostoker ( screened kkr ) approach which is a technique for ab initio electronic structure calculations based on the bimolecular interaction of free electrons with planar interfaces within aqueous solutions of a quantum mechanical system.    the method is applied to free electrons and a cu / co ( 001 ) system and its first successful applications are presented.
we present a thermodynamically consistent approach to the dynamics of free surfaces covered by large concentrations of insoluble surfactants.   we use the classical thin - film hydrodynamic coupled equations of motion for a thin liquid film covered by a surfactant monolayer, and then amend them to account for the adsorption / desorption process that takes place between the bulk liquid and the surface active agent at high concentrations. in particular, we introduce a new term in the dynamical equations that accounts for the advective and diffusive transport of the surfactent from the solid substrate to the free surface. using this new term, we show that the governing equations for the surfactor surface tension driven flow are more consistent than those for the control of the surface tension induced by the solutal marangoni effect, since they do not require any change in the surfacant surface diffusion term. moreover, we find that the influence of the Surfactant coverage on wettability close to three phase contact lines of very thin films, the effects of phase transitions in the Surfactant layer at high concentration, and also the impact of a nearby solid substrate on such phase transitions that may result in substrate mediated cond
the palomar transient factory @xcite has discovered two new members of the ca - rich gap transients, ptf11kmb and ptf12bho.   they are the first to meet the criteria for a class of intermediate luminosity ( " gap " transients ) with a faster photometric evolution than normal supernovae ( sne ), a rapid evolution to the nebular phase, and a nebular spectrum dominated by calcium emission. in this paper  , we present our observations of these objects, as well as analysis of both the transients themselves and their host environments. while the majority of the objects have a spiral host galaxy, many are found at substantial offsets from their presumed host galaxies, suggesting either that they originate in extremely faint systems ( such as globular clusters ;@xcite ), or alternatively that the progenitor has traveled from its birth site.
the aim of the present paper is to revisit the paper by dalmont et al.   ( 2015 ) on a diagram of oscillation regimes of reed instruments with respect to two parameters : the reed opening and the loss parameter. in this paper,   the analytical calculations presented are based upon a generalization of the fact that for the two - state oscillating regime, when no losses are present, the flow rate is a constant, and are limited to the limit cycles corresponding to the emergence and extinction bifurcations of this regime. as a result  , it is shown that the existence of an oscillating system is not possible with reverse flow, but can be verified by calculating the thresholds related to the instability of the regimes.. the results show that the extinction b if the mouth pressure is equal to or below the limit of existence and stability of the static regime, then the resonance opening at rest is stable, and that the formation of the new regime is independent of the resonator length.
egaps is a multi - band survey of the galactic plane.   the main aim of egaps is to obtain broad band ( u, g, r, i, z, y, j, h, ks ) and narrow band ( h@xmath0 and hei ) photometry of a 10 degree latitude strip centred in the plane all along the galaxy, i.e. covering the northern and southern galactic planes, and going down to 21st magnitude in the optical bands. by surveying a 10-degree - wide strip we are gathering photometry for 1 billion stars, one per cent of the total number of stars in the milky way. this will allow the detection and study of emission sources such as am  cvn systems and of short period variables such as Am cvns, magnetic cataclysmic variables ( cvs ), post - bounce cvs and other ultracompact binaries and fast pulsators.
in this article we discuss some social contagion processes which may play an important role in the dynamics of radical opinion formation.   the prime applications in mind are conflict situations where a highly armed alliance of foreign troops fights against a part of the local population which has been radicalized in a way such that western social classification dubs them terrorists. for these type of conflicts military solutions are inappropriate, since counter terrorist attacks on terrorists moving around in populated places may lead to a phase transition in the number of passive supporters induced by what is euphemistically called " collateral damage " as is common as a consequence of counter - terrorist attacks and increase the willingness of civilians to become members of radical groups.
the spectral - efficiency / bit - energy tradeoff is the key concept capturing the tradeoff between bandwidth and power in the low - power regime.   it is shown in @xcite that when the receiver has imperfect fading side information, input signals with increasingly higher peak power are required to achieve the capacity as @xmath1. on the other hand, limiting the peakedness of the input signals, when neither the receiver nor the transmitter knows the fading, is known to have a significant impact on the achievable spectral efficiency in the high - power regimes. in this paper, we continue our study of noncoherent rician fading channels by considering the minimum energy per bit required for reliable communication when the input signal has limited peakiness.    we show that the minimum received bit energy for an average power limited discrete - time single - input single - output fading channel with gaussian noise is@xmath11 db.. we also show that efficient signaling schemes can be developed using the minimum bit energy at zero spectral efficiency as a function of the spectral efficiency curve.
in the analyses of cp - violation in nonleptonic @xmath0 decays, only some intermediate states are usually taken into account.   many authors restrict their studies to elastic rescatterring ( e.g., a pomeron exchange ) only. however, it has been pointed out that nonzero inelasticity strongly affects the extraction of final state interaction ( fsi ) phases in models based on quasi - elastic rescaterring. in this paper   we perform a simplified analysis of these corrections which should be introduced into the short - distance ( sd ) quark - line diagrams used in most studies of @x Math0 decayed mesons. using a tree - dominated model of the decay, we estimate the types and the number of states produced in the first stage of the non leptonic decay. as in other existing models, we take these states as composed of two ( flying apart ) resonances ; these resonances are assumed to rescatter into @x math1 through regge exchange. by estimating the contribution from an average single in elastic intermediate channel for each state, we find that the total number of channels involved in the process is very small.    we also find
we investigate the influence of strong gravitational lensing on the polarization of a cloud of particles moving through the radiation field of a thin accretion disc.   we find two critical velocities at which the polarization vector changes its orientation between transversal and longitudinal one. in the case of a cold cloud,   the polarization velocity is faster than that of a warm cloud, and the polarization lorentz factor is lower in the cold cloud than in the warm cloud. in cases of a black hole - enhanced signal from a source near the black hole horizon, however, the polarization speed is much slower than that in the other cases. to test the validity of the model parameters, we show that the time delay of the retro - lensing effect depends on the temperature of the cloud and the alignment of the source and the observer. by taking into account the polarization information, we find that the stokes parameters of the scattered radiation are more sensitive to the direction of the light - curve rotation than the polarization rate.
quantum entanglement is a powerful quantum energy resource that has wide applications in quantum information processing and quantum heat engines.   the increasing of the size of the quantum system is essential to overcome the decoherence effects and to increase the thermalization capability of quantum thermodynamics, which is essential for quantum heat engine applications. here  , we present a new scheme for the generation of large - scale atomic w states via an all - optical expansion mechanism for polarization - based entangled photons, which can deterministically expand an @xmath0-photon entangled state by adding one or two photons at a time via accessing only one photon of the w state of the entangled photons. using the monte carlo simulation, we show that the experimental accessibility to the prepared w states is improved by introducing detection mechanisms for post - selection to find out whether the attempt has been successful or not, and by shrinking the final size of each prepared w state in the successful attempts.
we investigate the dynamics of several vortex filaments that are all nearly parallel to the same @xmath8axis.   we derive a two - dimensional system of coupled equations for the filament positions, which is called the point vortex system or kirchhoff law, and we observe that the system combines two different aspects of the dynamics. on the one hand  , the linearized self - induced motion of each filament is represented through the schrdinger operator, and on the other hand, the interaction of the@xmath21th filament with the other filaments is represented by the potential field, which corresponds to the velocity generated by the otherfilaments. in the case of straight filaments,   the system is thought to be a simplified model for the dynamic evolution of filaments.. the existence and uniqueness of solutions are discussed.
a new method for the fabrication of a scanning tunneling microscopy and spectroscopy ( stm ) tip with an sc material has been developed.   the technique is based on the deposition of a @xmath2 layer of pb on a mechanically cut ptir tip and then covered by a@xmath3 layer of ag, which serves as a protection against the oxidation of the surface layer of the tip. in order to obtain a sharp tip,   a voltage pulse is applied between the tip and an au target inside the stm vacuum chamber at a temperature of ~1.5 k. the resulting tips are superconducting and allow for atomic resolution, but the gap values vary from one tip to the other, ranging from a few tenths of a mev to up to 1.5 mev. this variation is due to changes in the tip apex geometry and composition, which can be explained by the proximity effect induced by the bulk.
dissolving the " tragedy of the commons "   @xcite is a central concern of studying cooperation in humans.   vast experimental work on public goods game has focused on two different conditions which would lead to high contributions to the public pool, punishment and reward. in this article, the mechanism in the optional public goodsgame   is investigated experimentally, and first time, the cyclic strategy pattern in full state space is demonstrated by means of velocity. for the first time  , it is pretended that if the defectors have the highest frequency, the loners soon become most frequent, as do the cooperators after the lonsers and defecators. on average,   the number of defectors decreases over 50 rounds, and the numbers of cooperators increase over the next 50 rounds. however, the results, based on the initial conditions they manipulated, did nt come out in the subsequent real experiment. therefore, in the perspective of evolution, the empirical cyclic dynamic pattern in the full statespace has not been proved experimentally. in order to test whether the rock - paper - scissors type strategy cycle exists in the real experiment or not, we conducted an experiment in which a sample group
bayesian methods of inference are widely used in astronomy and cosmology and are gaining popularity in other fields, such as particle physics.   bayesian methods require the evaluation of a ` likelihood'function describing the probability of obtaining the data for a given set of model parameters at each point in parameter space. for some cosmological and particle physics problems   each such function evaluation takes up to tens of seconds, making markov chain monte carlo ( mcmc ) applications may require millions of evaluations. using an artificial neural network ( nn )   reduces the number of likelihood function calls by an order of magnitude or more, but further gains can be achieved if we are able to speed up the performance of the likelihood itself. here   we present the blind accelerated multimodal bayesian inference ( bambi ) algorithm, which combines the use of nested sampling and the multinest algorithm, and uses a nn to train a network to predict the likelihood function after a specified number of new samples have been obtained from multinerest. once a network is trained that is sufficiently accurate, its predictions are used in place of the original likelihood function for future samples for multinests. using the network
the hera experiments at cebaf and cleo are the first to investigate the photo- and electroproduction of neutral vector mesons with highly virtual photons at intermediate and high energies.   the experimental data are presented in terms of qcd - inspired pomeron exchange, which is used to study the transition from non - perturbative to perturbation production mechanisms.    the results show that the form factor at the quark - pomerin vertex for the photoproduction process is very similar to that of the usual pomerone exchange, except for the fact that the energy of the process is the only large scale in which the two - gluon aspect of the pomers is perturbatively affected. within this formalism for vector - meson electroproduction with highlyvirtual photons   it is shown that the soft - pomereron exchange is also related to the skewed parton distribution in the proton. as a link between hard inclusive and exclusive reactions which generalizes the ordinary parton distributions,   these results are discussed.
we have studied the switching of stt - mram@xcite by starting with infinitesimal normal modes of oscillation about an initial uniform state, and continuing them to finite amplitude ( sec. ).   we find that the transition from a quasi - uniform state to a fully uniform state is a process of incoherent switching in which the lowest - frequency mode oscillates first, then the higher modes, and finally the exact normal mode, which will gradually disappear as the system evolves according to the llg ( landau - lifshitz - gilbert ) equation. for elements large enough to be stable,   coherent switching is possible, but it is difficult to understand because of the complexity of the switching process.. we have found that the transitions are more complex than previously thought, and that the effects of damping and overdriven spin torque on the transition between the two states are negligible.
neutron stars are fascinating objects to probe exotic states of dense matter that can not be otherwise studied in a terrestrial laboratory.   the central density of its core surpasses the nuclear density by a few times and the exact nature of its internal structure is yet to be understood. among the various theoretical models proposed to explain its structure and characteristics, the density dependent ( dd2 ) mean field ( rmf ) model has been widely applied to study the neutron star matter @xcite. in this paper   we show that the values of both symmetry energy and its slope parameters in all the most popular and widely used parametrizations to model neutron star structure, such as gm1, tm1,nl3 etc, are fully consistent with the experimental and observational constraints for the current dd2 model.
we consider the problem of the quantum bouncer in the context of the generalized uncertainty principle ( gup ) in the form @xmath0=i\hbar(1+\beta p^{2})$ where@xmath1 is the gup parameter.   we use two equivalent nonperturbative representations which exactly satisfy the modified commutation relation and find the corrected gup corrected energy spectrum of the qbouncer. using these representations, we can relax the assumption of the smallness of the Gup parameter and obtain the solutions for arbitrary values of @x Math1. to show that the semiclassical results agree well with the quantum mechanical results even for the low lying states, we consider the case of a test particle which is bouncing elastically and vertically on the earth s surface as a manifestation of the particle - wave duality.
we study transmission of monochromatic thz radiation with well defined linear polarisation through a thin nbn film with magnetic field applied parallel to its surface.   transmission is measured for horizontal and vertical linear polarisations utilizing the wire - grid polarisation. in this case,   the relative transmissions of the horizontally and vertically polarized radiations should be equal in zero magnetic field because the angle between the electric vector of the incident beam and the extraordinary ray axis of the birefringent sapphire substrate is @xmath8. transmission anisotropy of transmission can be regarded as a sign of vortex presence.
we present an analysis of the late gamma - ray burst ( grb ) 121027a, which has extremely bright and long flares that last up to @xmath17 s post the grb trigger.   the x - ray flares share the same relations between spectral peak energy and burst energetics that have been found for long grbs with the prompt@xmath0-ray data, such as the @x Math12 relation ( the amati - relation ; amati et al. 2002 ) and the @Xmath13 relation ( yonetoku et al. 2004 ).  in addition, the concordance cosmology with parameters @x math18 km s@x maths19 mpc@xMath19, @x mathematics20, and @x mathematical21 is adopted to calculate burst energetic values. using the results of the analysis, we propose that the late flares are due to extended central engine activity at late times.
the single stable isotope of beryllium, @xmath1be, is a pure product of cosmic - ray spallation of heavy ( mostly cno ) nuclei @xcite.   analyses of be abundances in metal poor stars have found a relationship between  = log @xmath2 - log @Xmath3 and log(be / h ) with slope close to one, and between =@x Math4 0.5 and log ratio at lower metallicities, these results suggest a primary production of be in the early galaxy. as a primary element, and assuming cosmic - rays to be globally transported across the early galaxies, be may show a smaller scatter than the products of stellar nucleosynthesis at a given time, suggesting its potential use as a cosmochronometer. in this letter, we report the discovery of an extremely be enriched halo star, hd 106038
the dissipation of a quantum system can be used as a resource for quantum information processing.   this paper presents a stroboscopic time - evolution scheme for the generation of maximally entangled quantum states, which is based on the design of a dissipation that acts quasi - locally on different parts of the system. in order to obtain the desired quantum state,   the dissipation must be driven dissipatively into a superfluid phase with a fidelities comparable to those obtained by more standard unitary schemes. using a set of multi - qubit gates and dissipation steps, we show that such a scheme can be achieved in an analog fashion ( i.e. using always - on couplings without individual addressing ), and that it can be generalized to provide a variety of multipartite entangled states.
superradiance is a general phenomenon in open quantum systems where the excitation can be coherently spread over several sites under the influence of different environments with competing effects. here   we focus on a ring - like structure of two - level systems coupled with nearest neighbor tunneling amplitudes which has been recently considered in literature as a model for the coupling of molecular aggregates to the electromagnetic field or to a central core absorber.   the system is equivalent to a tight binding model where one excitations can hop from site to site, and the efficiency of excitation transfer is determined only through a comprehensive analysis of the effects due to the interplay of all those environments. by using the single - excitation approximation  , we show that superradiance can be achieved in the presence of both a common decay channel and a static disorder, which induce fluctuations in the site energies of the protein scaffold, in which photosynthetic complexes are embedded, and that these fluctuations are position dependent, but time - independent. when the aggregation is coupled to a single decay channel, the rate of the site energy fluctuations is cooperatively enhanced, while when the aggregate is not coupled to the same channel, it is suppressed. this behavior
we propose a scheme to cool and measure the 3d motion of a nanosphere by tem00, tem01, and tem10 modes of a single cavity driven by a single laser.   we show that each one of these three modes can be coupled to the motion of an optically trapped nanosphere in each dimension via a cavity @xcite. for detecting the individual collisions between molecules and the nanosphere, we use the tem00 ( or tem01 ) mode of a cooling laser at tem00/tem01/tem10 frequency, and the tem10 mode of the cavity at tem10/tem12.5 frequency. using this scheme, we find that the mass of the molecules and surface temperature of the nanospheres can be measured with ultrahigh precision at the same time.
a single scalar field with an exponential potential is known to drive power - law inflation.   the recent paper of liddle, mazumdar and schunck recently proposed a novel model of inflation driven by several scalar fields with exponential potentials. in this paper   we show that the scaling solution for these fields is the late - time attractor by choosing a redefinition of fields ( a rotation in field space ) which allows us to write down the effective potential for field variations orthogonal to the scaling solutions and show that this potential has a global minimum along the attractor solution.
we use a color - magnitude data obtained by the optical gravitational lensing experiment collaboration for 12 fields scattered across the galactic bulge to construct a three - dimensional model of the mass distribution in the galactic bar.   the model is based on the observation that the red clump stars lying at the positive galactic longitudes are systematically brighter by @xmath9 than those lying at negative@xmath1., we find that the nearer side of the bar is at the same galactic longitude as the star cluster at which the observed asymmetry in surface brightness is observed, and that the galaxy is a triaxial structure with the near side in the first galactic quadrant.. this finding is consistent with the hypothesis that the galactic Bar is a large stellar bar with semimajor axis of @x math7 and inclination placing the nearer part of the Galactic Bar at positive galacticLongitude. using the model we also show that the observed microlensing rate of the nearby stars can be accounted for by the presence of stars placed in the near parts of the galactic bars.
in quantum mechanics there is no microscopic arrow of time.   any state can be propagated to the future as well as to the past, so that there is a complete time symmetry. in order to explain this fact,   a group of scientists around ilja prigogine ( nobel prize in chemistry 1977 ), referred to as the " brussels school ", has worked out a quantum mechanical formalism especially applying to unstable systems, where time symmetry is claimed to be broken at the microscopic level. here   we review the rigged hilbert space formalism and show how it works, how it applies to physical systems and what its advantages over standard quantum mechanics are.the second part of this paper is devoted to the role of time symmetry within the riggedhilbert spaces formalism.    apart from its practical advantages, the brussels school points out that a microscopic arrow for time evolution can be implemented here.
we present numerical evidence that a proper modification of the standard ramsey interferometry technique ( srt ) on interacting two - level ensembles can be minimized and surprisingly to some extent even reversed.   the technique takes advantage of the atomic interactions to suppress decay by transferring the atomic excitation to subradiant collective states, which are then used for an enhanced ramsey spectroscopy allowing for a significantly higher precision than even for independently decaying atoms. in consequence, the total ensemble spin is shifted towards zero by spreading the individual spins by predefined amounts almost homogeneously around the equatorial plane of the bloch sphere. using this method we demonstrate that it works almost as well in 3d regular lattices.
quantum parameter estimation considers how to estimate parameters associated with the evolution of quantum systems by physical means.   a theory of quantum estimation, derived from the laws of quantum physics and statistics, has been developed and applied to various evolution processes yielding important results for various metrology situations. in this article   we consider various estimation protocols for the constrained situation where _ when the available initial state of each qubit is mixed. using the single qubit depolarizing channel as an example  , we show that the optimal estimation protocol requires qubit pairs, each initially in an entangled pure state, and that states displaying entanglement or correlations amongst more than two qubits will not give any advantages to estimation accuracy.
the alignment of the major axis of the host galaxy with the polarization direction of the quasar has been proposed as a key factor in the unification model of the agn.   we investigate the possible existence of a correlation between the direction and orientation of the linear optical polarization of type1 and type2 rq / rl quasars for which high resolution visible / near - ir images are available and with optical polarization data reported in the literature. using the mcs deconvolution method @xcite, we calculate the acute angle @xmath2 between the directions defined by the direction of each polarization and the orientation of its major axis ( @x math1 ) of the hosts galaxy from the observed polarization data. while no particular behavior is noted at redder wavelengths, a clear dichotomy appears in the uv / blue domain where the type1 quasarts tend to have their ee preferentially aligned with the polarized direction, these two axes being mainly orthogonal in the type2 objects.. moreover, the observed alignment effect seems to be independent of the radio - loudness.
centaurs are a transient asteroidal population whose orbits cross those of the outer planets.   they are believed to have their origin in the oort cloud, a vast and remote spherical reservoir of cometary material tens of thousands of astronomical units in diameter that completely surrounds the solar system. at 11.0%   ( 30 out of 272 catalogued objects in the jet propulsion laboratory small - body database ), centaurs have the highest retrograde fraction among all the dynamical groups or asteroid families. here  , we present a comparative statistical analysis of the properties of known prograde and retrograde centAsteroids that reveals compelling reasons to single out the largest retrograde objects. by using a numerical model based on the @xmath6-body simulations, we show that the three largest known ( in terms of absolute magnitude, @x Math0 = 9.3 mag ) retrograde asteroids are ( 342842 ) 2008  yb@xmath3 ( @x math0 = 8.1 mag ), 2011  mm@x maths4 ( @ xmath0 = 10.2 mag ) and 2013  lu@xMath0 = 7.8 mag.    these
the economic science has been influenced by physical concepts from its very beginning.   the newtonian principles, formulated at the end of the seventeenth century, have powerfully influenced most branches of science - economics undoubtedly. as a well developed branch of physics perfectly equipped with mathematical apparatus  , mechanics has permanently served an inspiration for theoretical constructions in economics. looking for recently arisen intersections of physics and economics one arrives to econophysics which describes the phenomena of development and dynamics of economic systems by using a strictly physically motivated methodology. in this paper   we present instructive examples of how the methodology of constrained dynamic systems, commonly used in classical mechanics, can be used for solving economic problems and, in this way, we supply instruments to present and demonstrate this interdisciplinary topic on the undergraduate level of physics education. being intended for the students of physics without preceding knowledge of economic theories, the examples given in the paper are based on intuitive economic terminology and supplemented by easy - to - read explanations and interpretations of the economical background. apart from the illustrative potential of the examples, the look at standard methodology procedures used in mechanics from a completely different point of view enables the reader to reach a better understanding of the physical background of these
we extend the notion of " forbidden words ", that is, symbol sequences whose appearance is restricted by the dynamical constraints, to systems with delays.   we derive forbidden words for the delayed system from the properties of the undelayed map and show how they are related to the time delays in the system.we apply the theoretical findings to two important practical problems : detecting synchrony in a large network with multiple delays using measurements from only a few nodes, and determining unknown values of the delay value in the network.
we present a detailed investigation of the properties of a two - dimensional ( quasi- ) quasicondensate in which the superfluid is best described as a kosterlitz - thuringless ( kt ) phase fluctuating condensate.   we use the hartree - fock - bogoliubov ( hfb ) formalism to investigate the coherence properties of this state, which are crucial for the question of whether it is best defined as a bec or as a quasia. using the hfb - popov approach, we show that the temperature - dependent coherence length and momentum profile of the kt phase can be obtained from the excitation spectrum of a bose gas with confinement in a harmonic trap. by comparing these results with those of previous experiments, we find that the time - independent, second quantized form of the grand - canonical many - body hamilton operator for the system is given by @xmath3, where the coupling parameter that characterizes interparticle scattering is derived from an approximation to the two - body t - matrix in the zero - energy and zero - momentum limit.conclusionsthe results of this study provide detailed predictions for comparison with
the lhcb collaboration has recently reported on the measurement of rare decays using the full lhc run i dataset  @xcite, with an integrated luminosity of @xmath11 fb@xmath10.   the results confirm the robustness of the experimental data, and are consistent with the hypothesis that new physics contributions to muonic operators are responsible for the observed anomalies in some cases.
we present a new approach to the non - perturbative dynamics of @xmath0 gauge theories in the chiral sector, which amounts to computing directly the relevant path integrals without making any approximation or assumption.   our results can be seen as the open string solution of the model, since we start from the gauge theory action and express the solution in terms of averages over colored partitions that can be explicitly evaluated. using this approach, we provide a full justification of the matrix model and equivalently a proof of the open / closed string duality for the chirality sector of the @x Math0 gauge theory.
the casimir effect involves the difference between the energy of a field subject to some constraining boundaries and that of the field with such constraints removed.   the classical limit of the effect, even for the electromagnetic ( em ) field, has not been clarified to date. in this paper   we address this problem by examining the case of a radiation field confined between two parallel conducting plates. using the first plate as a reference  , we find that the casimir energy at zero temperature due to vacuum fluctuations in the mode @xmath7 is the sum of the total energy density of the em field with the plates as boundaries and the energy density in an arbitrarily large volume,@xmath15.    the classical solution is shown to be robust to nonvanishing corrections to the classical value.
parametric resonance of magnons in yttrium - iron garnet ( yig ) crystals under the influence of an external microwave field has been observed by demokritov and co - workers.   this phenomenon is usually referred to as bose - einstein condensation ( bec ), but we argue that the coherent state generated in these experiments should perhaps not be called a bose-einstein condensate, because the condensation is not accompanied by spontaneous symmetry breaking in this case ; instead, the microwave field gives rise to a term in the hamiltonian which explicitly breaks the @xmath6-symmetry of the magnon Hamiltonian.. we propose an extension of the conventional kinetic theory of parametric resonances in magnon gases which includes the order parameter dynamics on equal footing with the kinetic equations for the distribution functions. since we would like to clarify conceptual points rather than perform explicit quantitative calculations, we derive our extended " s - theory" within the framework of a simple toy model which we motivate in the following section.    we show that this model contains the essential physics of parametrical resonance and bec of magnrons ; in particular, in the regime of strong pumping the
the imaging atmospheric cherenkov technique ( act ) is a powerful tool for the study of astrophysical sources of very high energy ( vhe, e @xmath0 100 gev ) gamma rays.   the advancement of the act over the past decade has been directed towards detecting lower energy gamma - rays, thereby closing the gap between space - based instruments and ground - based observatories, and improving the sensitivity to weaker gamma - ray sources. in this paper   we present a novel image processing method based on wavelets to enhance the image processing technique. by using wavelets,   an image can be reconstructed from a large background of hadronic showers without the need for any additional cleaning procedures. as a result  , the image reconstruction results are more precise and more consistent than those obtained with the traditional cleaning methods.
we show that certain algebraic properties of quandles imply that the cocycle invariant is constant, or takes some restricted form, for classical knots.   in particular, we prove that several specific rig quandle, including some of those conjectured in @xcite, have constant coc recycle invariant values for all classical knots for some non - trivial @xmath0-cocycles.
stochastic abelian sandpile models ( sasm ) are important subclass of the manna model.   they are able to describe the avalanche behavior seen experimentally in the piles of granular media much better than the deterministic models, e.g. the bak - tang -wiesenfeld ( btw ) model @xcite. however, the theoretical understanding of models with stochastic toppling rules is much less than that of their deterministic counterparts. in this paper  , we discuss a special case of the more general abelia distributed processors model ( adp ), which is a combination of the two types of models. using the algebra of the addition operators to determine the steady state of the model, we show that each jordan block is at most of dimension @xmath5. for systems of size up to @x Math6, we determine the numerically exact steady state and determine the asymptotic density profile by extrapolating the results.
the seyfert 2 galaxy ic  2560 contains an h@xmath0o megamaser, with a peak flux density of up to @xmath7 jy.   this object has been observed with chandra in 2000 october, via a short ( @x math11 ks ) observation, reported in iwasawa, maloney, & fabian ( 2002 ), and even before that, with asca ( ishihara et al., 2001 ). here   we report position - velocity resolved interferometric mapping of the water vapor maser emission from this galaxy with acis - s, using a series of 50 ks points obtained in 2004 february. for the first time, we show that the emission can be clearly identified with respect to the accretion disk of ic 2560, which is a type-2 active galactic nucleus ( agn ) with a geometrically thin accretion disc ( ngc  4258 ) and a central engine ( ~26 mpc ) associated with a very high flux density ( up to ~1.5 jy ). by combining the results of the previous observations with new data from a 50 k
the superconducting properties of single - crystalline metallic nanofilms with atomically uniform thickness down to a few nanometers are investigated in the case when the bottom of one of the relevant single - electron subbands approaches the fermi level.   we show that the pairing in such a subband exhibits a clear molecule - like trend, which is very similar to the bcs - bec crossover investigated at length in cold atomic gases, i.e., the formation of discrete levels for the perpendicular electron motion  in tunneling spectra and the coupling of the two - band(subband ) superconductors by the density of states ( dos ) in the conduction band.    our finding significantly compliments the recent experimental results for the temperature dependence of the pairing gap in the @xmath0-@xmath7 subband, where up to half of all the cooper pairs nearly collapse as the depth of the subband decreases.
quantum cloning is a fundamental process in quantum computation.   it has been shown that there are some quantum - computational tasks whose performance can be enhanced by making use of quantum cloning. here  , we investigate the circuit complexity of universal quantum cloning and estimate the time a quantum cloning machine requires to make two copies of identical pure state inputs from a two - dimensional system ( qubit ). by comparing the cloning time @xmath3 with the decoherence time@xmath4 of the qubits in a physical system, we can estimate how much quantum information can be copied practically.
the escape of ly@xmath0 photons from interstellar gas is facilitated enormously by the presence of outflowing interstellar gas, and scattering off these outflows effectively doppler shifts them out of resonance into the red wing of the absorption line profile. in models of this process  , the outflow is often represented with a geometrically thin shell of gas ( e.g. @xcite ).   however, the shell - model has recently been shown to have difficulties in reproducing the strength of ` blue bumps'in a subset of observed spectra, especially in cases where more than @xmath3 of cold inflowing gas is present. here   we show that scattering across a shock front can give rise to such blueshift, and that the acceleration mechanism which gives rise to this effect is fermi - like. using quantum mechanics simulations, we find that the frequency of the photon diffuses through frequency - space as it is scattered by the material on either side of the shock front, in turn changing the optical depth of the gas to the photon, and hence the extent of the blue wing of its absorption spectrum. while the effects of bulk gas motion and microscopic motion of individual hydrogen
diamond crystal plates with ( 111 ) surface orientation are of primary importance for front - end diffracting x - ray crystal optics at synchrotrons due to the greater intrinsic energy bandwidth of the 111 bragg reflection and the resulting flux of the reflected x - rays compared with those of higher - order reflections.   however, production of the ( 111)crystal plates with large defect - free regions is a more challenging task compared with production of plates of other orientations close to the  direction. in this work   we report on the production of type iia diamond crystals with 100-@xmath1m - thick and 300-mm - thick surfaces using the high - pressure high - temperature ( hpht ) crystal synthesis method @xcite. by using a modified mounting solution for the self - seeding xfel monochromator that was previously developed for the diamond ( 001 ) self - seed xfels, we show that the crystal thicknesses of the newly synthesized crystals can be increased from 100 to 300  m and from 300 to 500  m depending on the alignment of the crystal plate and the graphite holder where the plate is loosely mounted.
brownian motion is one of the most ubiquitous transport phenomena in nature, thermally induced molecular collisions in a solvent impart momentum to small particles and they hence acquire a random velocity @xcite. in over damped systems, where inertia is overcome by viscous damping, this velocity becomes rapidly uncorrelated in time. in this case the particle s velocity becomes an effective white noise and its position is what is mathematically known as pure brownian motion.   the problem of diffusion in a random potential has been extensively studied, in the cases where the diffusion constant exists one can use field theoretic methods such as the perturbation theory and the renormalization group to estimate it for both gaussian@xcite and non - gaussian potentials. except for a particular case in two dimensions  , in higher dimensions no results are known.in this paper we address the question of how an ultimately diffusive system attains the diffusive regime. using the finite time correction for continuous time random walks ( ctrw )   we show that at a coarse grained level a brownian particle diffusing in a periodic potential can be viewed as a c trw.    furthermore, we then use a kub
the first order behaviour of all quantities near the accretor for an axisymmetric flow, and in particular their departure from sphericity, is studied in numerical simulations of the bondi  hoyle   lyttleton ( bhl ) accretion flow.   the results show that the rate of accretion of mass into the accreting sphere is more than 100 times larger than that predicted by hoyle & lyttton ( 1939 ), and that the ratio of scales between the accretion radius and the radius of a compact star, moving with a supersonic velocity, is typically of order : @xmath6 where@xmath7 is the schwarzschild radius.. the role of the boundary conditions at the surface of the accreteor is closely related to the position of the sonic surface, and we shall use analytical arguments to obtain some insights on this question.
we investigate the self - steepening of the kerr nonlinearity in two - dimensional ( 2d ) photonic crystal waveguides ( phcwgs ) using a combination of experimental and computational approaches.   we show that the self-steepening of this nonlinear effect is a key property of the waveguide geometry, which is modulated by the wave angular frequency of the waves at the wavelength range from 0.1 to 1.0 cm / s for optical frequencies up to tens of femtoseconds near the mode cutoff. as a result,   the effective nonlinear kerr parameter exhibits a linear enhancement with the group index squared in the presence of slow - light @xmath2, with the first factor arising from a larger electric field for a given power ( nonlinear enhancement ), and the second from longer effective optical path length ( linear enhancement ). while the effects of these two factors are well described in the literature, the contributions of the other two factors, namely the modal area and linear refractive index, have received surprisingly little attention. despite this, we demonstrate that the latter two factors can be used to enhance the nonlinear properties of the dispersion of the
we report on a young rotation - powered pulsar, discovered in the course of the parkes multibeam survey of the galactic plane ( @xcite ) at the 64-m parkes telescope in nsw, australia.   the pulsar has been the subject of regular timing observations at parkes since 1999 may, and we have used archival radio, x - ray, and @xmath6-ray data to infer its characteristic age from the observed times - of - arrival ( toas ) and rotational residuals. using these data, we show that it is likely to be a young neutron star, with a mean age of ~5kyr, and a rotation frequency of ~1.2 j / cm2 per year. by fitting the toas to the time series of observations, we find that the object is rotated at a rate of ~8 truecm1 per year, and that its initial rotation period is about 1.5yr. during the first few years of its existence   it experienced a glitch in its rotation, which was corrected for by changing the position of the observatory time standard, and this was followed by a rapid increase in the number of toas
coherent feedback quantum control schemes enable the design of autonomous controllers for quantum systems.   they do not rely on measurement based feedback, which is always accompanied by undesirable side - effects, including the addition of excess noise from amplifying quantum signals up to macroscopic levels and increased controller latency. in this work  , we demonstrate that coherent feedback can be used to enhance the bandwidth and frequency detuning of squeezed states of light produced from a network of two optical optoelectronic opos ( opos ) coupled in a coherent feedback configuration. as the parameters of the feedback loop and controller opo are varied, the behavior of the combined system departs in a significant way from that of the individual plant opo system. while it has been shown that cascading parametric oscillators ( feeding the output each into the input of the next ) can enhance entanglement and squeezing of the final output light, the merits of arranging the oscillators in a coherence feedback configuration warrant careful study in order to find ways of enhancing the squeezing produced while minimizing the number of oscillators used to achieve it. here   we present the theory to describe the full opo network with coherent feedback, and show that the properties of
we report the observation of a compact black hole, grs 1915@xmath0105, using the fpma and fpmb detectors of the nustardas nustar observatory.   we observe the accretion disk of this object over a span of 59.8  ks with both detectors, and find that the black hole is in a very compact central corona, with an emission line consistent with a relativistic jet - like configuration.    the spin of the blackhole is inferred from the reflection spectra, and the results are compared with those of previous studies of similar objects using the ccd spectrometer.
magnetoresistance ( mr ) data of low-@xmath0 nb / alalox / nb, and slightly overdoped  intrinsic josephson junctions in single crystals of bi@x Math1pb@x maths2sr@x math3cacu@x mathematics3o@xMath4 -2212]intrinsic tunnel junctions are analyzed by intrinsic tunnelling spectroscopy ( its ).   the results show that the magnetotunneling of self - heating @xcite at the sub - gap bias with low dissipation power is strongly influenced by the size of the self - heated junctions, which leads to effective obviation of the superconducting gap @xmath11 and the normal state pseudogap ( pg ) energy scales for both low- and high-@Xmath0 junctions. however, the effect of doping on the quantum mechanical properties of the junctions is more pronounced for the low-joints. using theoretical calculations, we find that the qp density of states ( dos ) away from the fermi surface increases with increasing number of
attractors for dynamical systems are traditionally viewed as being asymptotically stable invariant sets which have a neighbourhood that absorbs all sufficiently close initial conditions.   recent work on globally coupled networks of oscillator with delayed pulse interactions ( @xcite ) indicates that extreme cases of riddled basin attractors,  unstable attractors _, can appear, where there is a neighbourhood of the attractor such that almost all points exit from the system under the dynamics. in this paper   we give a rigorous explanation for the appearance and robustness of these attractors in such systems. by following an appropriate open set of initial conditions, we show that the system discussed in section   exhibits unstable attracting periodic orbit(s ) and that they persist for an open set.we also prove that the network of unstable attractes is a hybrid system, including a generalization of the set of possible response functions.    we present a simple recipe of how to perturb a smooth flow with a robust heteroclinic cycle to a smooth semiflow with a network of instability.
the effect of the stage of emergence of the coronal loops on the resonant absorption of magnetohydrodynamics waves in solar corona is investigated.   the results show that the period ratio of the decay time of the first harmonic of the fundamental mode of the transverse kink mode in the observed coronal loop is significantly lower than that of its first harmonic, which is caused by the effects of density stratification and the shape of the loop. also for the first overtone of both the fundamental and first - overtone modes, the rate of decay increases when the stratification parameter increases from 0.5 to 1.0.    the latter is due to the formation of a strong inhomogeneity along the @xmath6-axis normal to the magnetic surfaces of the plasma with the field lines in the opposite direction to the surface of the loops. at the same time  , the frequency of the oscillations of the two modes increases with the increase in the size of theloop. finally, the decay times of the second harmonic of one of the modes increase with the increasing size of each loop. erythrombotic damping rates of the initial and final modes are found to be
we investigate the four - quark content of the @xmath1 by searching for the decay @x Math10, which is the dominant decay mode with a branching fraction of 89.2%.   the results are compared with data from the cleo - c detector and monte carlo simulations of the known charm physics processes. in the analysis, we find that the decay mode is dominated by a positron candidate and an independent final state, both of which are strongly favored by cabibbo.
bipartite networks are composed of two types of nodes with no links connecting nodes of the same type.   they are used in many applications, such as recommendation systems, networks of collaborations, and networks of metabolic reactions. compared to traditional uniparous networks,   less is known about the organizing principles determining the structure and evolution of bipartite network, partly because only unipartites projections of these networks are often considered. in this work   we build the hidden variable formalism for bipartited networks, based on the formalism developed earlier for unip articulite networks. by using a set of hidden variables drawn from some distributions, we show that every node of each type in a bipartitite network is assigned a number of Hidden Variables, and then every node pair of different types is connected with some probability which depends on the hidden variables of the two nodes. moreover, we study the topological properties of networks with hidden variables, and confirm in simulations our analytical results for these networks.
we derive new estimates of the source - integrated cosmic radiation background ( crb ) at various frequencies and derive formal error estimates for each.   these estimates are compared to those obtained by the arcade 2 and tris collaborations, which have recently released absolute measurements of the sky temperature of the radio background over a wide range of frequencies from @xmath14ghz to 8400 mhz. in both experiments we find that the observed temperature is about 5 times greater than that currently determined from radio source counts, with the most notable excess of emission being detected at @x Math17@xmath18 1. here   we reexamine the observed radio source data to see if this difference is due to some previously unknown source of extragalactic emission. using source count data from continuum surveys carried out from 1979 to 2009  , we show that the sources which contribute the most to the observed sky brightness temperature are likely to be coming from ordinary star - forming galaxies at ~6.5- to ~8400-mhz. however, our results are not entirely consistent with the results obtained by @xcite and @excite. while the majority of the observed emission is likely to come from the sub-@
we propose a new method for the study of flow effects in relativistic nuclear collisions.   we use a more general method, which includes as a part both directivity and two dimensional sphericity methods in a natural way and gives a clear physical meaning to the analysis. using this method, we investigate the shapes of azimuthal distributions of different particles, and try to detect and study of anisotropy of different kinds. in order to detect complex three dimensional event shapes, we slice longitudinal variables, e.g., transverse momentum, multiplicity, or transverse energy in relatively narrow ( pseudo)-rapidity windows into different windows, and perform fourier analysis in each window. by correlating and combining the fourier coefficients in different longitudinal windows  , we can obtain a three - dimensional event shape. from the results of the analysis   it is found that the origin of the anisotropic collective flow could be different : hydro - dynamical flow due to pressure gradients, shadowing, both, etc. however, what they have in common is some collective behavior in the evolution of multiparticle production process. therefore, we often use the term transverse collective flow for the phenomena
x - ray emission is an excellent tracer for high temperature and/or high velocity activity in galaxies.   the study of massive star end - products, in particular, is important to the understanding of the interplay between stars and the diffuse hot interstellar medium ( ism ), or the " ecosystem " of galaxies. with the _ chandra   x - ray observatory, we now have a new tool to probe the high - energy properties of the galactic center ( gc ) region at a distance of only 8 kpc. here   i give an overview of some of the new high energy astrophysical phenomena revealed by the data from the_chandra  observatory.
we present detailed theoretical models for the intensity distribution on the sky produced by the central b star and disk of a be system.   we compare these models to observations collected at the navy prototype optical interferometer ( npoi ), which are consistent with the observed spectroscopic profiles of the emission lines observed in the h@xmath3 spectral lines for the classical be stars @xmath6dra, @x Math7psc, and @x math8cyg. using the bedisk code developed by @xcite, we compute the temperatures in the disk given the energy input from the central star s photoionizing radiation field, by enforcing radiative equilibrium. as the disk density model contains several adjustable parameters, values for these parameters   can then be extracted from the match to observations.the results show that the radial power - law index for the vertical structure of the disk is determined by hydrostatic equilibrium in the radial distance from the star s rotation axis and the height above the equatorial plane ; the radial density distribution in the equator is given by an @x maths11 power-law.    the temperature of the disks is assumed to be equal to or greater than 1.5 kcal / mol
the bursting pulsar, a low - mass x - ray binary ( lmxb ) located on the sky close to the galactic center, produces two distinct outbursts during which @xmath5 10,000 hard x - rays were generated.   the bursts are type ii events due to spasmodic accretion of material onto the surface of a neutron star caused by some instability within the accretion disk. in the case of gro  j1744@xmath028, cannizzo ( 1996 ) has proposed a model where conditions at the inner disk radius of the accreted material lead to a lightman - eardley instability in the accrete flow, causing the bursts. here  , we investigate the existence of coherent pulsations with a period of 0.467 s in the persistent x -ray flux of the bursting pulsa using a combination of high - resolution transmission electron microscopy and photoluminescence spectroscopy. for each outburst, the burst occurrence rate ( corrected for source exposure time ) remained constant at roughly 40 events per day after the first day of each outburst, but the persistent, pulsed and burst flux was diminished by roughly a factor of @
the j/@xmath0 elliptic flow is measured in pb - pb collisions at @xmath6 = 2.76 tev in the @x Math2 range 0 - 10 gev / c and rapidity range @x math7.   it is found to be consistent with zero in all of the measured @x maths2 range within uncertainties.
wolf - rayet ( wr ) stars are surrounded by dense stellar winds giving rise to free - free emission extending from ir to radio wavelengths.   typically, this emission is characterised by a power - law spectrum of the form @xmath2, with values of the spectral index and radio brightness temperature of @x Math4  k. a small number of wr stars have radio emission that exhibits quite different properties : negative spectral indices and brightness temperatures @x math5  k or higher, properties that are characteristic of non - thermal emission. in this paper  , we discuss the radio emission from wr146, which was first resolved in high resolution observations with merlin and attributed to an early - type companion to the wr star.
gauged q - balls have attracted much attention because they can exist in all supersymmetric extensions of the standard model @xcite.   specifically, they can be produced efficiently in the affleck - dine ( ad ) mechanism and could be responsible for baryon asymmetry and dark matter. in this paper  , we address the question whether such large gauged Q - balls can be formed in realistic or cosmologically - motivated theories without additional fermions nor a singular potential. to find spherically symmetric symmetric solutions of the so(2 ) symmetric scalar field coupled to a gauged field @xmath14, we consider the  v_gauge())=m^22 ^ 2-^4 +  with   m^2, ,  m^{2>0}/s = d^4x, where & & : =,   f_:=_a  a _, + & & d__a:=____a+a+ab_b  ( a, b=1,2 ). here, we show that there is a maximum charge and size of normal q - Balls in both models.
the z - like tracks of the six persistently bright neutron star low - mass x - ray binaries ( lmxbs ) @xcite show secular changes in their spectral and variability properties.   these changes are related to the position of the source along the z - track, and to the presence of quasi - periodic oscillations ( qpos ) and noise components. here   we review the current knowledge about the nature of these changes, and discuss the possible mechanisms by which they may be involved.
the fractional josephson effect is a consequence of the crossing of andreev bound state energies as a function of the phase difference between the superconductor and the topological insulator.   it has been studied theoretically in nanowire setups where majorana fermions are realized using quantum spin hall insulator edge states or surface states of a three - dimensional topological Insulator. here  , we demonstrate the possibility to generate this effect in a setup of two double quantum dots coupled to an @xmath0-wave supercond conductor and subject to an inhomogenous magnetic field. by analyzing the robustness of the effect with respect to level detunings and coulomb interactions,   we show that the phenomenon is not only robust but also reversible.
we have recently published an article, where we have developed a novel model of particle acceleration via the damping of centrifugally excited langmuir waves.   this mechanism strongly depends on the relativistic effects of rotating magnetospheres, which are present not only in active galactic nuclei ( agns ) but also in the galactic sources. in this article   we apply the new mechanism of acceleration to stellar black holes ( sbhs ) and study efficiency of a corresponding process and the role of these objects in producing the high energy cosmic rays. by taking into account the accretion rate of accreting matter onto the black hole, one can show that the bolometric luminosity, @xmath6, is given by@xmath1-ray binary systems.. the theoretical model of the landau - centrifugal drive ( llcd ) is applied to the results and the results are compared with the physical parameters.
the equilibrium properties of the equilibrium state for a simple model of a monomer - monomer @xmath0 catalytic reaction on a one - dimensional chain are studied.   the adsorbed particles of species @x Math1 and @x math2 undergo continuous exchanges with their vapor phases acting as reservoirs, i.e., they adsorb onto empty lattice sites on the chain and may thermally desorb from them, while the vapor phase as a reservoir is maintained at constant chemical potentials. within this model, if any adsorption of both species occurs at neighboring lattice site, they instantaneously react and both leave the chain, and the reaction product@xmath13 is completely removed from the system. for this model   we derive the expression for the pressure of the adsoriated particles, which provides the complete thermodynamical description of the system, and we present exact asymptotic ( in respect to the chemical potential ) results for the mean densities of the particles and for the compressibilities of the systems.
magellanic stream ( ms ) was found as a long filament of  gas around our galaxy @xcite.   it is the only clear example of a gaseous halo stream in the close proximity of milky way@xcite, and it gives us important clues to the physical interaction between galaxy and its satellites in detail. in order to study the ionization mechanism and kinematics of the ms  clouds, detailed spectroscopic follow - up observations are required. however, positional information necessary to perform a medium to high dispersion spectroscopy has been so far very limited. in this letter, we report the positions and shapes of the  emitting regions we detected at the northern part of ms iv with spatial resolution of 1.5 arcsec pixel@xmath1 using a fabry - prot interferometer. for each region, we used r - band and three narrow band filters ( n657, ha6577, and ha6417 ). by using the mosaic ccd data reduction packages, we reduced the image size from 4.1 arcsec to 2.0 arcsec and the transmission curve at the corner was shifted by 10  to the red from that at the center.
the compactness of a presupernova star s core is an important structural characteristic that affects whether it will explode as a supernova.   the connection between this structure and the likelihood of explosion has been noted many times by @xcite, but little attention has been given to explaining just why the compactness has the values that it does, or why different groups obtain different core structures for models with similar main sequence mass. in this article  , we discuss the recent work on the systematics of neutrino - powered supernova explosions as a function of the density gradient around the iron core.
we propose a new method for multi - view semi - supervised learning based on support vector machines ( svms ).   the proposed method is based on regularization theory and capacity control of function classes. in this paper  , we give theoretical insights on the generalization error and the empirical rademacher complexity of the proposed approach. as an appropriate integration of these terms and thus the effective use of information from labeled and unlabeled data, our method has the potential to outperform many related methods.. experimental results are reported on synthetic and real - world data sets.
g@xmath0  yang  mills theory has attracted considerable attention recently as a means to look at the physics of color confinement in quantum chromodynamics from a fresh new angle.   the g@x math0  group has a trivial center ; the center of its universal covering group is also trivial, and there seems to be no reason to believe that the group center plays any important role in the theory at all. however, even in this theory, the static quark - antiquark potentials for static color charges from any representation of the gauge group, including the fundamental one, must be asymptotically flat, and the theoretical string tensions are expected to rise linearly over a certain range of distances. here   we discuss the effect of casimir scaling at intermediate distances on the behavior of the qcd vacuum condensation model proposed by @xcite et al. in ref..@xcite.
we present a general response theory for the dynamical conductivity tensor of strongly - interacting low - dimensional ( q1d ) systems, @xcite, which uses both an essentially exact semiclassical description of the coupling between valence electrons and external electromagnetic fields @xmath6 and a quite general description about the structure of the electron - hole propagators.   the result is the current - dipole kubo formula for the dynamic conductivity in the memory - function approximation of the charge - charge correlation function from the bethe   salpeter equation. to emphasize the connection between the present theory and the ordinary transport theory, we determine the explicit form of the interband conductivity using real and imaginary interband dipole vertices as well as the lorentz local field corrections @xmr@xmath5moo@x math3 and @xyr@xmr.2. here   we show that the results are consistent with the results of experimental methods which probe charge and spin fluctuations which presumably occur at finite wave vectors.
the mass measurements that are required for calibration of the mass - observable relations of galaxy clusters at higher redshifts become increasingly difficult to perform because of the strong assumptions that are necessary to interpret x - ray ( hydrostatic equilibrium ) or velocity dispersion ( virial equilibrium ) measurements.   we present a new method for measuring the average mass of high-@xmath6 cluster lenses based on the magnification effect of weak gravitational lensing ( wl ) as proposed by @xcite, which does not require one to resolve the sources and hence can be applied at higher Redshifts. by stacking a number of clusters in a combined color and position space using the cluster red - sequence method from the spitzer adaptation of the red - sequences cluster survey ( sparcs ; *???   * ; *????,1 up to @xmath14 1.4 ) we find that the average masses of the observed clusters are approximately twice as large as those of the background sources.    the results are discussed in detail.
the mechanism responsible for the smallness of neutrino masses relative to the charged fermion masses remains as elusive as ever.   we have developed a scheme to account for this phenomenon within the framework of the simplest four - dimensional gauge structure, without non - abelian discrete flavor symmetries. by imposing a cyclic flavor blind 53 symmetry in a theory with enlarged symmetry breaking sector : two higgs doublets and a singlet, we find that the resulting model has an accidental spontaneously broken u(1 ) symmetry that leads to the seesaw mechanism as well as the dirac nature of neutrinoless fermions.see research article http://www.biomedcentral.com/1471-7007/9/8/5
density functional theory ( dft ) is used to calculate molecular anharmonic potential energy surfaces for nine molecules : the parent benzene molecule, pyridine, pyrimidazine, pyrazine, 1,2,3-triazine, 1.2,4-triazabenzene ( _ sym/-triazine ), 1.,2,5-tetrazine (_ sym-(triazine)-triazine) and 1, 2,4,5 -triazine (  sym'-triazine-)triazine.   the azabenzenes are obtained by systematically replacing the ch moieties in benzene by nitrogen atoms. at the ccsd(t)/cc - pvtz level,   all of the molecules undergo distortion from the idealized @xmath3 ring to a@xmath4 geometry, which is a local minimum situated some 23 kcal / mol above the @x math5 diazide global minimum@xcite. using the b97 - 1 functional with the tz2p ( triple - zeta plus double polarization ) basis set, it is possible to obtain rms accuracies on the order of 10 @x Math1 or better
the gluon - fusion of a pair of lepton partners induced by quartic couplings of two sleptons and two squarks is studied at the one - loop level in the minimal supersymmetric standard model ( mssm ).   the results are consistent with the notion that the quark - initiated process is not a special feature of supersymmetry models, but rather is a consequence of the irreducible renormalizable interactions of four matter partners, of type @xmath13, in which the partners have spins that differ from those of the standard model particles. these interactions may, therefore, offer a new handle to discriminate supersymmetrical models from other extensions of thestandard model.
the generation of short pulses of electromagnetic radiation is a primary challenge of modern physics.   this paper considers coperative radiation emitted by electron bunches when charged particles pass through crystals ( natural or artificial ) under the conditions of dynamical diffraction of elctromagnetic waves. in the case of two strong waves excited in the crystal,   the forward wave is emitted at small angles with respect to the particle velocity, while the diffracted one is emission at large angles with Respect to the direction of electron motion. for both waves,    the radiation intensity is proportional to the squared number of particles in the bunch.. the effect of the electron bunch length and the geometrical parameters of the system is also considered.
in this article we study the asymptotics of large directed graphs with constrained densities of edges and outward directed @xmath0-stars.   we find that, in all our models, graphs have either uniform or bipodal structure as the number of nodes becomes infinite. when we constrain both edge and @x math0-star densities ( but not both ), we find a sharp change at the interface between the two subgraphs, which is called a phase transition. by using the large deviations principle  , we show that the phase transitions are due to maximizers of the entropy or free energy of the model.
the time - dependent many - body schrdinger equation ( tdse ) can be cast in a hydrodynamic form in terms of the density and expectation value of the velocity operator for the electron liquid  @xcite.   these equations are centrefold in hydrodynamics and describe both laminar and turbulent regimes. if we could derive similar equations in the quantum case we would have a powerful tool to investigate a plethora of effects related to electron - electron interactions on a much simpler level than solving for the many-body sch thirdinger equation.    in this paper   we show that transport in nanoscale conductors satisfies the conditions to derive quantum navier - stokes equations for the velocity field of the fluid as a function of its density, visco - elastic coefficients, pressure and the geometric confinement  . this is simply due to the geometric constriction experienced by electrons flowing in a nanostructure which gives rise to very fast " collisional " processes. in this regime  , one can truncate the infinite hierarchy of equations of motion for the particle stress tensor to second order and thus derive quantum hydrod dynamic equations. with these equations   it is possible to reder
the italian - dutch collaboration in the search and followup of grb optical transients ( ots ) at the eso telescopes has been working together for the last 2 years.   the aim of this programme is to exploit the high detection rate and the unprecedented localization capabilities of hete - ii, which will allow increasing the number of accurate grb locations observable from eso.    the large programme has been structured in order to achieve the following aims : ( i ) determining the redshift distributions of grbs ; ( ii ) studying the nature of circumsource environment, and probing the ` dark'afterglow population ; ( iii ) establishing the reality and nature of gr b - supernova connection ; ( iv ) constraining the physics of the ` fireball'model ; ( v ) performing the first ever near - infrared ( nir ) observation of a grb with a visible counterpart ; ( vi ) investigating the role of the cosmological properties of the host galaxy in the formation of the light - emitting diode ( loe ) signal associated with the grb ; and ( vii ) exploring the possibility of an interaction between the two main types of afterglows, i.e. x
we report the results of a pilot study into generating high spatial resolution maps of interstellar extinction in the magellanic clouds ( smc ) using swift uvot images.   we have 17  square images of a northern pointing in the smc in all six colour filters, and tested our method in a smaller region with a 200 pixel ( @xmath0 3.3 ) square area in the north - west corner of the field where the background is relatively low in all filters and the image is less crowded. in all but eight cases,   the fits were relatively good with a reduced@xmath2 less than 2.    further work will involve making the photometry and background subtraction more sophisticated, obtaining a more appropriate stellar model for the fits, and then constructing an extinction map of the entire smc field.
superconducting nanowire single photon detectors ( snspds ) are attractive candidates to replace avalanche photodiodes in applications such as free - space optical communications, quantum cryptography networks, and quantum computation.   however, the current state of the art in snspd design is limited by low system detection efficiencies ( @xmath1s ). here  , we show that the optical polarization and changes in the geometry ( pitch and fill - factor ) of snspdc structures impact their absorptance and efficiency. for devices with 200 nm pitch and 50% fill factor, we found that 21% of light incident from the front was absorbed for parallel polarization, while only 10% wasabsorbed for perpendicular polarization. using a numerical model that predicts the absorption of photons through the nanowires, we also measured the effect of these changes on the detection efficiency of the snspdt.we found that the results of our experiments match the predictions of our model to within the uncertainties in our knowledge of physical and optical parameters. moreover, we find that the absorbance of photons polarized perpendicular to the nanowsires is different from that of those polarized parallel to thenanowires. finally, we propose a
quantum rabi model ( qrm ) is a basic model in quantum optics which is successful in the understanding of a range of experimental phenomena, such as the well known quantum rabi oscillation and vacuum rabi mode splitting.   recently, with the advancement of quantum technology, the so - called strong coupling regimes have been experimentally realized in many devices, and thus a full qrm has to be reconsidered in order to describe well the physics observed in these strongly coupling regimes. here   we propose a variational _ frequency - renormalized multipolaron expansion _ method to improve the performance of the trial wavefunction based on the concept of polaron and anti - polaron picture for the calculation of the qrm wavefunction in the crossover regime. by introducing the frequency renormalization feature,   the energy and wavefunction can be efficiently calculated at low oscillator frequency using the variational coherent - state expansion method.. the results show that the proposed method is more accurate than the current one in terms of the calculations accuracy in the weak coupling regime, particularly at the low oscillators frequency.
gravitational lensing by large - scale structure along the line - of - sight can alter the observed number density of galaxies on the sky.   this magnification bias effect is measured through the excess or deficit in the counts of galaxies around background qsos, which are fainter than the limiting magnitude of the galaxy population and may be included in the sample if they are brightened due to lensing. although several measurements of the qso - galaxy cross - correlation have been made, most studies with radio loud qso have found correlations in excess of lensing predictions, in most cases the amplitude of the correlation is much higher than that expected from gravitational lensing models. here   we review the literature on the relationship between the magnifications bias effect and the effects of dust obscuration and dark - matter clustering, and discuss the implications of these findings for the theoretical modeling of the lensing effect.
we investigate the effect of interactions between particles having opposite spin on the quantum spin hall ( qsh ) physics of an interacting system of ( pseudo-)spin-1/2 particles that are subject to a spin - dependent magnetic field.   we find that such inter - species interactions significantly alter the expected qsh physics, but they also open up new opportunities for tailoring the properties of quantum many - particle states. in particular, we show that when the two interacting particles have opposite spin, the classic results obtained for spinless ( or same - spin ) particles   @xcite are not applicable to the case of particles with opposite spin. by using numerical exact - diagonalization studies with up to 6 bosons  , we demonstrate that this difference is due to the existence of a fractional version of the qsh effect that is independent of the ordinary fractional qh effect in multi - component systems.
color superconducting quark matter is expected to occur naturally in the cold dense cores of compact ( " neutron" ) stars, where densities are above nuclear density, and temperatures are of the order of tens of kev.   it is also expected to exhibit a rich phase structure, with many different patterns of pairing between the two light quarks, the up and down quarks and the strange quark, which plays a crucial role in the bcs mechanism for cooper pairing. here   i discuss some of the properties of color - flavor - locked ( cfl ) qcd matter that would affect observable features of compact stars.
many fundamental experiments in quantum mechanics can be written and fully understood in terms of a quantum circuit.   the current state of the art, however, provides a poor platform for implanting these circuits on what can be considered a universal quantum computer. by post - selecting   experimenters condition their statistics only on those experiments that ( will ) meet a certain criteria such as the result of a projective measurement performed at the end of the experiment. here   we show how to overcome this difficulty theoretically and experimentally, in the setting of weak measurements. using an ensemble quantum computer with nmr architectures, we demonstrate two properties of weak values associated with post - selection : weak values outside the range of eigenvalues and imaginary weak values which are independent of the number of qubits used in the experiment and the effective evolution of the measuring device during the measurement. when the interaction between a quantum system and a measuring device is weak enough, the back - action is negligible and the effects of the experimental conditions are negligible.. moreover the effect of the weak values is proportional to a complex number of real and imaginary strong values, a complex numbers which is a function of the pre - selection, post - select and the desired observable
the field theoretic renormalization group ( rg+ope ) is applied to the case of a compressible fluid, whose behavior is governed by the stochastic navier - stokes equation.   the resulting stationary scaling regime is associated with an infrared attractive fixed point of the corresponding multiplicatively renormalizable field theory model. in a similar fashion as has been done for an incompressible case  , the double expansion scheme is employed. here the formal expansion parameters are @xmath2, which is obtained by using the operator product expansion ( ope ) procedure and the same formal parameters as those used for the generalization of kolmogorov s scaling theory to the cases of non - gaussian velocity field and passive advection by kraichnan s ensemble. from the results   obtained we conclude that the proposed model is not unrenormalizable.
in @xcite, we have studied the structure of algorithms from the operad / prop point of view.   we have shown that the set of programs does not have much structure at all and that types of algorithms have better structure. in this paper, we look at the equivalence relations that describe when two programs are " similar " by looking at the number of sets of equivalence relationships that one can have with every set of algorithms. using these relations,   it is shown that with each set of equivalenced algorithms, there is no such thing as a program that is " equivalent " to another program if both programs perform the same computable function. on the other hand, for each type of algorithm, there are some programs that are equivalent but not the same if they perform different computable functions.
the early stages of massive star formation are poorly understood.   we have a very limited range of wavelengths at our disposal with which to observe the earliest stages of this process. in order to understand better their formation process, we need to observe massive stars at ages even younger than 10@xmath4 years before they develop ultra - compact regions ( uc regions ). for this purpose, we have used radio continuum and molecular line emission observations from the mid - infrared to the sub - millimeter wavelength regime to investigate the existence of hot cores of compact and dense molecular gas in the near - stellar environment around young massive stars.. these types of sources are known as high mass protostellar objects ( hmpos ) since they do not possess radio continuum emission and are internally heated by massive protostars. here   i review the current state of knowledge about the formation of hot molecular cores of massive stars in the era of interferometric interferometry.
we present monte carlo simulations of chains of length up to @xmath25.   these simulations are made with the perm algorithm developed recently by one of us @xcite, and applied successfully to a number of different polymer problems. for each problem, we study the corrections to the annealed approximation using the random bond model. in the first step  , we evaluate the quenched average of the free energy. as usual with random models, this is a very difficult task, while the second step is rather easy to perform an annealing average over the disorder. for several models of random spin systems   it is well known that such an ananealed approximation becomes exact in the high temperature phase, in the thermodynamic limit and at sufficiently large dimension.the same is thought to be true for the present model. for the second stage, we show that the corrections can be performed by means of a two - parameter phase diagram in the variables @x Math0 and @x math19.    the main advantage of this diagram is that we can pass continuously from positive ( repulsive, hydrophilic ) to negative ( hydrophobic )@xmath0. when the chain length reaches infinity
in the following we give a new explanation of the area law of black hole ( bh ) entropy and the more general and stronger holographic principle of quantum gravity.   we also provide convincing arguments that an important structural ingredient of the deep structure of our quantum vacuum is a network of microscopic wormholes. in contrast to e.g. string theory and loop quantum gravity, which both employ the quantum laws more or less unaltered all the way down to the remote planck scale, we view the holographic hypothesis as a means to understand how both quantum theory and gravitation do emerge as derived and secondary theories from a more fundamental theory living on a more microscopic scale.
we study the cp violation of the stau polarization in the two - body decay of a stau using the minimal supersymmetric standard model ( mssm ).   we show that the normal tau polarization is a triple product asymmetry which is sensitive to the phases of @xmath0,@xmath1, and @x Math2 in the staus - neutralino sector. for nearly degenerate stau masses,   a strong stau mixing is obtained which results in the formation of a phase which violates cp by a factor of about 1.5. with heavier stau soft susy breaking parameters, however, the phase is not violated by any of the above phases.    these results are consistent with the observation that the phase of the trilinear scalar coupling parameters of the third generation sfermions does not violate cp.
the self - consistent mean - field method of the interacting boson model ( ibm ) @xcite is applied to the mass region @xmath0, extending the analysis made in@xcite to the neighboring exotic hf and yb nuclei.   the results show that the nuclear ground states in this mass region exhibit a transition between prolate and oblate equilibrium shapes as a function of the number of nucleons, with the critical point around @x Math10 having a pronounced @x math9 softness. for the pt isotopes and some of the os and w isotopes, the transition from prolate to oblate shape is due to the interaction of the proton with the neutron, while for the yb isotopes it is related to the exchange of proton energy with neutron energy.
the spherical hecke central ( shc ) algebra constructed in @xcite is a limit of a symmetrized double degenerate he cke algebra.   it acts on instanton partition functions as the kanno - matsuo - zhang transformation of the young diagrams summand, which is the main reason behind the agt correspondence. in this paper  , we investigate the fate of the shc algebra in the nekrasov and shatashvili ( ns ) limit of the @xmath6-background in which one of the equivariant parameters tends to zero. in both cases,   the associated integrable model bare some similarities with the@xmath7 xxx spin chain, and the system of bosons with delta interaction studied by c. n. yang ( qnls ), and describes the solution of the quantum non - linear schrdinger equation in a sector of fixed number of particles, and will be referred to as _ qnLS_qnls_, although in a different way. in view of these results, we propose that the bifundamental contribution to the nanosecond partition functions of the ns limit
the sunyaev - zeldovich ( sz ) decrement of @xmath0 in the x - ray luminosity - limited sample of rich, intermediate - redshift clusters abell  773 using the ryle telescope  ( rt )  @xcite has been detected.   we have used the rt data to estimate the hubble constant from this cluster, which, when combined with other clusters from the sample, will give an estimate of@x Math0 unbiased by the individual shapes and orientations of the clusters.
accurate wave statistics are crucial to establish concise predictions as well as realistic design values for wave heights and wave - induced velocities.   second - order nonlinear contributions are applied to account for the mutual interaction between wave components. in this paper  , we revisit the contribution of second - orders of nonlinearity on wave orbital velocity with a stochastic model. using monte - carlo simulations for unidirectional and directional wave fields, we show that deviations from the gaussian distribution of the probability density function of the surface elevation are reduced by directional spreading in deep - water and enhanced in finite water depths. taken into account the fact that waves can be considered as a stationary, ergodic and gaussian random process, we conclude that the second-order nonlinear contribution is not sufficiently strong to induce deviations of the upper and lower tails of the probabilities density function from the normal distribution.
pulsar b1913 + 16 ( @xcite ) was the first binary pulsar discovered, and it remains one of the best systems for studying relativistic gravitation. in this paper  , we present a new analysis of the pulse times of arrival ( toas ) derived from five - minute integrations of the pulsar signal at frequencies near 1400 mhz measured at arecibo observatory from 1981 - 2012.   we find that the time derivative of projected pulsar semimajor axis is significantly longer than previously reported, while the shapiro gravitational propagation delay is much shorter than previously predicted. among the parameters newly measured with various degrees of accuracy   are theshapiro spacetime propagation delay, a relativistically correction to the elliptical orbital shape, and the time derivatives of projected pulses at frequencies below 1400 mhz.
we have made an all - sky extinction map with 5@xmath0 resolution using the far infrared ( fir ) maps of the infrared astronomy satellite ( _ iras _ ) and the diffuse infrared background experiment ( dirbe ) on the cosmic background explorer.   we used the color - color correlations between 60, 100, and 140 @xmath3 m that were found by hibi et al. to improve the maps, we assumed the dust temperature and the dust extinction can be obtained only from the _iras _ data. in the present study, we show that the results of this study are consistent with the model by li & draine ( 2002 ).. however, we find that the models do not explain the multiband imaging photometer for spitzer ( mips ) and  iras_ data.    we propose a new model for the calibration of the extinction maps.
the solar neutrino problem is now established more or less independently of any details of solar models.   the analysis has been made more systematic by a series of works that is categorized now as the " model - independent analysis ". in this paper  , we update these analyses by including the newest data of the high - statistics water cherenkov detector, superkamiokande @xcite, as well as those of the latest @xmath0cl@xcite and the @x Math1ga experiments @xficite. using the new values of the expected event rates obtained in the latest standard solar model ( ssm ) calculation by bahcall and pinsonneault ( bp98 ) , we show that sensible astrophysical modifications of the solar model such as the low - temperature ( @x maths7 ) model are convincingly excluded by the present data.. we also try to develop a new method for illuminating the suppression pattern of various solar neutRino flux originated from different fusion reactions in a less model - dependent fashion.
the monopole condensation is one of the most favored mechanisms of the confinement of the monte carlo gauge.   the monopoles are defined within the maximal abelian projection of @xmath0 lattice gauge theory and they are always observed as ( closed ) trajectory. in this paper   we present results of measurements of the geometrical characteristics of the monopole trajectories belonging to the percolating cluster that fills in the whole of the lattice @xcite. using the simulated annealing algorithm, we measure the average length of the segments and average euclidean distance between the crossings, the average value of the crossings per unit of 4-volume, and the scaling properties of various physical quantities related to these trajectories. for all cases we observe simple scaling properties which confirm the reality of the map monopoles as physical objects.
the energy budget of gamma - ray bursts ( grbs ) is estimated from late - time radio afterglow observations over timescales of hours to weeks.   the kinetic energy of the decelerated ejecta can be estimated using the well - established sedov - taylor self - similar solution, with negligible beaming corrections, and is in good agreement with the isotropic - equivalent blastwave kinetic energy ( @xmath9 erg ) measured from the early afterglowing. however, the existence of a substantial component of mildly relativistic ejecta must be determined from observations at late times when such putative material can refresh the forward shock. here   we show that this can be done by re - modeling the afterglows of 3 recently observed long - duration grbs ( grb970508, grb980703, and grb030329 ) using the same methodology used by @xcite to model the radio emission of grb 970508 on timescalexigenes of ~1.5 hz and ~2 hz, respectively, and find kinetic energies of @x Math17 erg for each burst.  also, we find that the energetic properties of the slow
we introduce a mathematical tree - shape framework for geometric trees, which is suitable for statistical analysis.   the framework is based on the concept of a geodesic tree - space, and assumes a space of tree - shapes endowed with a distance, and is closely connected to geodesics, or shortest paths, between tree- shapes. in this framework,   we model topologically intermediate trees as collapsed versions of trees with differing tree topology, and glue the portions of Tree - space together along subspaces that correspond to collapsed trees. using gromov s approach to metric geometry, we show that quotient euclidean distance ( qed ) generically gives locally unique geodesives and means, whereas finding geode - shaped means for tree edit distance ( ted ) is ill - posed even locally. by combining the two frameworks, we find that qed can be used to investigate statistical methods for tree - like structures which have previously not been possible, like different well - defined concepts of the dimensions of the shape space.
we present a stochastic approach to the characterization of non - markovian quantum dynamics in the context of the reduced density matrix.   we use a single time - local liouville - von neumann equation ( sln @xcite ) to obtain the dynamics of a reduced system through statistical averaging of random state samples generated by numerically solving an equation of motion for the reduced operator of the system from the unitary evolution of system and reservoir degrees of freedom. using this approach, we show that the dynamical properties of the reduction matrix can be fully characterized by tracing out the degree of freedom of the thermal reservoir from the global dynamics of the whole system and then solving a single polynomial time - locally stochastically solved langevin - von Neumann equation with respect to the measured values of the dipole energy and the water temperature. as a result  , we find that the rate of dissipation of water at low temperatures is linearly proportional to the speed of the diffusion of water molecules into the reservoir ; however, when the water molecules are moved to higher temperatures, the process is more spatially restricted and the rates of diffusion are much slower. these results are consistent with the general theory of
the open cluster ngc 6791 is a notable object, being one of the oldest and most metal - rich open clusters in the galaxy.   it was selected for the present analysis due to both its high metallicity, which places it at the high end of the apogee target metallicities, and the possibility that it contains more than one stellar generation. here  , we present abundance results for iron, oxygen, and sodium in the h - band high - resolution spectra obtained by the apache point observatory galactic evolution experiment from the sloan digital sky survey iii ( sdss - iii ), which are used to measure radial velocities and chemical abundances of up to 15 elements in over 100,000 stars in the galactic bulge, disk, and halo. among the metals measured,   iron is the most abundant, while oxygen is the least abundant, with the exception of sodium, which is found in only a small fraction of the sample.. the results show that the selected sample contains two distinct populations of oxygen and sodium, suggesting that the cluster may contain multiple stellar generations.
metamagnetism in the two- and three - layer ruthenate compounds @xcite and@xcite has been investigated by means of a simple hartree - fock theory.   the magnetisation as a function of field, temperature and the band filling is obtained for a system with a single, two - dimensional electron band where the fermi level is close to a van hove singularity ( vh ). using the mean - field theory, we show that the magnetic phase diagram of these systems is in qualitative agreement with experimentally observed properties of the two - layer compound @xcite, and suggest that it might be understood in terms of band - structure properties.
the search for extra - terrestrial intelligence ( seti ) seeks evidence for life in the universe, through the detection of observable signatures from technologies that are expected to be possessed by advanced civilizations.   this paper explores the suitability of using very long baseline interferometry ( vlbi ) for targeted seti from potentially habitable planets.the target for this pilot study is the m - dwarf star gliese  581 ( gl581 ), located 20 light - years ( ly ) distant in the constellation libra @xcite. as the currently active _ kepler space mission aims to search for earth - sized planets in and near the habitable zone of sun - like stars,   more earth - like planets in habitable zones will be investigated for extra-terrestrial intelligence. in this paper   we present the first seti experiment conducted with vlrii. at a frequency of 1420  mhz ( 4462.336275 mhz )  , we detected a signal from a planet within the habitable region of gls581d ( gl587d ), which may be the first confirmed exoplanet with the possibility to sustain life on its surface. during the experiment, we used vl
a number of active galactic nuclei ( agn ) have been found to exhibit hi absorption toward the central parsecs.   models which have been proposed to explain this absorption suggest that disk or torus structures exist in agn on scales @xmath0100 pc from the central engine @xcite. here   we present a new study of a compact symmetric galaxy, pks2322@xmath4123, which is associated with a high - density active galactic nucleus ( hdna ) at a redshift of @x Math1=0.082 and has relativistic jets emerging from both sides of an inverted spectrum core. using vlba spectroscopy, we show that the source is well - aligned with the plane of the sky and has a circumnuclear torus - like structure near the center of the nucleus. as predicted by this model,   a significant fraction of neutral atomic gas can be expected within a range of radii determined by the midplane pressure in thecircumnuclear structure @xcites.
we systematically study the multifractal characteristics of different signals by means of the mfdfa method with different orders of the detrending polynomials.   we consider both the mathematical multifractals and the multifraction time series coming from real - world observables or generated by a computer. in this paper  , we focus on the singularity spectrum and its derivatives which are the most important characteristics of the analysed signals. for each type of signal,   the results show that the main determinants of the multifractories are the number of segments and the frequency of the disjoint segments. however, when the analysed signal is fractal, the second determinants are the size of the monofractal and the decreasing function of the analysing signal. for all the other two determinants, the single - order fluctuation function is the primary determinant of the multifractal characteristic. using a polynomial of too high order   can result in suppressing some of the low - frequency fluctuations which are erroneously identified as a part of the trend while using an order of too low order does not eliminate non - stationarity sufficiently.
we study a system of two distant inas / gaas quantum dots ( qds ) weakly coupled to a common cavity mode under coherent bichromatic excitation.   we show that dressing of one of the qds by the laser field can be effectively readout by the optical emission of a second qd, in addition to the cavity emission. this result is a significant advance over previous work @xcite in the use of qds for solid state quantum networks, as it demonstrates the feasibility of information transfer between distant qds coupled to the same cavity mode, bringing closer theUse of qd / cavity pairs as nodes of a network for quantum information processing.
long - duration gamma - ray bursts ( grbs ) have been detected in submillimeter ( submm ) and/or radio at redshifts @xmath0 @xcite.   the host galaxies of grbs are found to be subluminous and low - mass@xcite, but four of them have been firmly detected in both submm and radio. in this paper   we discuss the possibility that these submm - bright grb hosts may represent the hotter counterparts of cold and luminous sub millimeter galaxies ( smgs ).
we investigate the properties and limitations of a generic tractor beam mechanism for small beads trapped in an optical two - mode nanofiber.   we first study a rather idealized two mode model including only for forward scattering and some general absorption losses to identify the key parameter region for the appearance of tractor forces. in a second step  , we generalize to a more realistic description including the backscattered fields and loss to free space. while it seems difficult to find realistic favorable parameters for a tractor forces in multi modes nanofibers, hollow core fibers seem much more promising as they can be used to create 3d optical trapping positions along the fiber with strong evanescent field components. finally we go beyond the case of single particles and study how ordering and optical binding can be combined with tractor forces using a multimode optical waveguide.
the threshold expansion of the top quark pair production cross section in the third - order ( nnnlo ) qcd loop at @xmath0 is used to determine the top mass of the standard model ( sm ) particles.   the cross section is obtained from the expression - boson exchange of feynman diagrams in the non - relativistic effective field theory, and the calculation of the second - order qcd corrections is carried out by summing up the perturbation theory to all orders beyond the next - to - leading order. for the first time  , the results are compared to the results of the experimentally measured top mass measurements at the fermilab tevatron and the large hadron collider ( lhc ) run at@xmath7tev centre - of - mass energy using the threshold expansion method. while the difference between the two methods is not statistically significant, the differences in the calculations are highly significant due to the small three - velocity of the heavy quarks and the strong colour - coulomb force, which make the theoretical calculation of qcd correction corrections rather different from standard loop calculations.
electron transport through quantum dots ( qds ) is a well - known phenomenon.   the main signature of the kondo state in nanosystems as a qd connected to two leads is the enhancement of the conductance below@xmath1 up to the unitary limit ( @xmath2 ). in this configuration electrons transmitted from one electrode to the other   necessarily pass through the qd. in the present work,   we investigate the transport properties of a strongly correlated qd attached to two lead and to a quantum ring ( qr ) pierced by a magnetic flux, that in fact acts as a quantum box, which energies can be continuously modified by the application of the magnetic field. manipulating the parameters  , the system presents unexplored crossover behavior.the crossover between the continuous kondo and the discrete kondo regimes is found to be very interesting due to the strong many - body correlations between the conduction band electron spins in the leads and the localized spin in the Qd, when the temperature @x Math0 is below the kondone temperature.
the cosmic origins spectrography ( cos ) instrument was designed to provide high sensitivity, moderate to low resolution spectroscopy between 1130  and 3200  in the far ultraviolet spectroscopic explorer ( fuse ) band.   the nominal g140l/1230 mode provides coverage from the detector cutoff at 1850  down to @xmath3910, and two new modes, g130m/1096 and /1055, provide higher sensitivities and potentially much higher signal to noise at these wavelengths. while the cos diffraction gratings and the optical telescope assembly ( ota ) mirrors are coated with mgf@xmath0 protected aluminum ( typically used for wavelengths longer than 1150 ), these optics were expected to retain some first - surface reflectivity below the mgf#@x math0 transmission cutoff at @x Math11150. during cos on - orbit testing, it was immediately obvious that the instrument and the ota retained significant sensitivity down to approximately 900 .    the success of the g140 l/12 30-b observations suggested the possibility of shifting the wavelength scale to the blue so that the central wavelength ( falling on the detector gap ) is @x maths1 800
the early universe was a highly uniform and homogeneous mix of dark and baryonic matter with baryon fraction @xmath2.   if this primordial mix persists as individual gravitationally bound structures emerge during the course of cosmic evolution, then the baryony mass of any given object would be @x Math3. here   we reverse the logic and ask what fraction of the expected baryons are actually detected. in a series of experiments spanning a dozen decades in detected baryonal mass, we find that the mass of beryons known in each system correlates well with the total mass, but not as a simple proportion. for some systems,   the baries are in the intergalactic medium @xcite, while for others they are in either the gas or star - dominated interstellar medium. to account for this discrepancy, we divide our inventory into two broad categories of gravitationsally bound systems : those supported by rotation, and those supporting by random motions. among rotating systems, we distinguish between those dominated by stellar mass ( typically early type spirals ) and thosedominated by gas mass ( usually irregular and late type spiral galaxies ). among random motions, we show that the b
the minority game ( mg ) is a complex adaptive system in which agents compete for a limited resource.   the agents learn from past experience by evaluating the performance of their strategies, where each strategy maps the available global information ( i.e. the record of the most recent winning options ) to an action. in the mg,   there is a non - monotonic dependence on the memory size @xmath5 of the agents and the relative performance of the strategies oscillates as the game proceeds. here  , we show that the evolution of the mg can be viewed in terms of transitions in the global information space. in this space, the number of agents playing a given strategy and the corresponding anti - correlated strategy   are the nodes with the largest number of possible history bit - strings for a given value of @x Math5. when the agent memory size is low, the transition from one node to another is more rapid than when it is high. in order to understand the behavior of the population as a whole, we use the crowd - anticrowd theory, which is based on the fact that it is the difference in the numbers of agentsplaying a given Strategy and its inverse strategy that dictates the size of the
pseudogap phase of the boson fermion ( bf ) model is a manifestation of the pairing - wise correlations which start to appear in a system when the transition temperature @xmath4 is approached from above.   it means that below a certain temperature fermions start to couple into the pairs and these are, however, weakly ordered in phase due to the small superfluid stiffness. in this short paper   we extend our previous study @xcite to analyze the pseudogap shape and its variation with temperature. using the stm current conductance as an example  , we show that the particle - hole asymmetry can be explained by the existence of a new ordering taking place in a vicinity of the superconducting phase.
we propose an approach to the numerical evaluation of certain general, not necessarily rational, infinite products, which is based upon theorem  and pad approximation.   we illustrate this approach by applying it to the kepler  bouwkamp constant, defined as the infinite product @xmath16, and discuss properties of short gamma quotients at rational arguments. in particular, we offer an alternative proof of a result established in ramanujan s ( lost ) notebook @xcite and@xcite, which may be interpreted as a ( much simpler ) version of the chowla  selberg formula in the case of principal characters. finally, in section , consideration of an infinite product defined in terms of the thue  morse sequence leads us to a curious open problem posed by shallit.
the aleph experiment at lep2 has observed an unusual event with two high energy electrons, two high - energy photons, and a large amount of missing transverse energy.   the standard model ( sm ) explanation for this event has a low probability, but it can be accommodated by the susy models mentioned above. in the neutralino supersymmetric particle ( lsp ) model, the cdf event could be explained by the drell - yan process where the two s escape detection resulting in missing transversal energy. if this is the explanation for the cdc event, the best channel for discovery at leP2 is. in principle  . however, the predicted cross section is uninterestingly small. in gravitino lsp models, such as the no - scale supergravity ( lnz model ) and gauge - mediated supersymmetry breaking ( gmsb ) models, the events are more likely to occur in the region of parameter space where the second lightest neutralino decays to an essentially massless gravitinos and a photon with a 100% branching ratio. within these models,   one photon and two photon plus missing energy events are the best channels for discovery.
multipersistence homology is a generalization of the theory of persistent homology, which builds a bridge between computational algebraic topology and data analysis using homology as an effective tool to associate a computable invariant to a point cloud.   the main idea is to approximate the point cloud embedded in a metric space with an increasing sequence of simplicial complexes ( filtration ). by analysing the persistent, i.e. long living, homological features in the fil tration,   it is possible to infer the shape of the pointCloud.    multipersistent homology has been introduced by carlsson and zomorodian in the seminal paper @xcite, where the authors study the classification problem for multipers persistence homology modules. from then, several papers have considered these modules : the same authors and singh in@xcite developed an algorithm for computing their grbner bases and chacholski et al. gave a combinatorial multigraded resolution for multipersonal homologs. in this paper  , we give a new presentation of multipersistence modules. by using this, we are able to extend a version of the algorithm presented in
the polaron transport theory developed by holstein in his seminal work @xcite was based upon perturbation expansions with its validity sometimes limited to cases of small transfer integrals.   however, the theory has been widely used for qualitative interpretations of experimental data, including the temperature dependence of band - narrowing effect as well as the crossover from band - like behavior to hopping transport with increasing temperature. here  , we present a new microscopic model of polaron charge transport in organic molecular crystals based on a canonical transformation of the hamiltonian with an element of optimization. using the monte carlo method,   the proposed model is found to be able to account for the off - diagonal exciton - phonon coupling that is not accounted for in the holstein model. despite the fact that the results obtained from this study are in agreement with those obtained from previous studies, the theoretical framework is not suitable for the case of simultaneous diagonal and off - diagonality coupling.
we report photometry of the central star @xmath0 car using acquisition images obtained with the space telescope imaging spectrograph ( stis ) and the advanced camera for surveys ( acs ).   we find that the star s apparent brightness has changed dramatically since 1998, when the most recent " spectroscopic event " occurred. during 2003, the star brightened at a surprising rate, from 0.3 to 0.5-magnitude in apparent brightness per year, while the surrounding " homunculus " ejecta - nebula appeared to be about 0.2-m Magnitude brighter than the center of the star ; this change is explained by dust along our line of sight to the star, but, as mentioned above, it is only vaguely understood at this time. here  , we also report surprising variations in the near infrared ( near ir ) brightness of @x Math0 car accompanied by measurements of the nearby continuum in the stis slit - spectroscopy data.
the existence of geometric phases in quantum systems has attracted considerable interest both from the theoretical and experimental viewpoints.   we consider the case of a spin 1/2 particle coupled to a slowly evolving magnetic field in the presence of a weakly dissipative medium as represented by a lindblad form superoperator@xcite, incorporated in a convenient and physically motivated frame. in the absence of dissipation,   the geometrical phase appears as a " delay " or an " advance " in the precession period of the bloch s vector with respect to the period dictated by the magnetic field s frequency. in order to make it explicit, we introduce the linear entropy ( or idempotency defect ) as a measure of purity loss.we show that the shrinkage of the modulus of the @xmath2 component of the magnetization of the spin 1&1/2 variable is due to the dissipation of the nonunitary part of the liouvillians of the hamiltonian in the adiabatic limit of the quantum system.
the solid - liquid interfacial free energy @xmath0 is a very important parameter in the theory of solidification.   it controls the barrier for nucleation of a solid in an undercooled liquid and the transitions between planar, cellular and dendritic growth regimes in metals, which in turn governs their final microstructure. despite its importance for both theoretical models and practical applications, accurate data for the value of @x Math0 are not known even for the case of simple elements. here   we discuss a novel technique to compute @x math0 which aims at being robust, efficient and transferable, and which is a promising candidate to extend the scope of interfacial energy calculations to the study of first order phase transformations.
we study the low energy physics of a three - leg ladder system of coupled antiferromagnetic spin 1/2 chains with periodic boundary conditions and an odd number of legs.   the model is called the spin - tube model, which consists of two non - equivalent xxz chains of spins and chiral degrees of freedom, in the presence of a biquadratic exchange. by analyzing in detail its effective low energy hamiltonian ( leh )  , we show that the dimerized ground state of this model falls in the universality class of the non - haldane spin liquids. in the case of xxz chain systems with a bquadratic coupling and for @xmath5, we find that the ising antifunctional order can compete with the dimeric order, and we describe the resulting phase diagram.
experiments of single steps in many motor proteins have revealed that the steps and dwell times obtained in many single - molecule experiments are not well described in terms of the cycle completions in enzyme kinetics.   this is because the average number of forward and backward steps differs from the average numbers of completed forward and reverse steps, and the average dwell times between steps differ from the mean cycle completion times. in this paper  , we extend the theory of step statistics by considering the distributions of conditional dwell times instead of mean values. for a large number of models relevant to describe reversible motor proteins, including motor detachments, substeps, and multiple pathways, we find a distribution symmetry for conditional dwell time distributions, and a simple relation between the dissipated free energy per cycle and certain conditional stepping probabilities.
we report on the evolution of the mass and mass - to - light ( @xmath1 ) ratio of eight bright galaxies in the luminous x - ray cluster 054 at@xmath0.   the fundamental plane is derived from the spectroscopic and photometric observations of the galaxies, which show that the @x math1 ratio of these galaxies evolves slowly out to @x Math0, when the universe was 50% of its present age. this suggests that the stars in massive cluster galaxies were formed at much higher redshifts than previously thought.
the effect of chromospheric activity on photometric techniques for measuring the metallicities of stars has been explored in a statistically meaningful way.   we compare the soft x - ray luminosity measured by the _ rosat _ satellite and a photometric metallicity calibration ( martell & laughlin 2002, hereafter ml02 ) which was developed to be more accurate for higher - metallity stars than the schuster & nissen ( 1989, hereafter sn89 ) calibration. using the latter as an indicator of stellar activity  , we find that the retest values of the ml02 calibration are significantly lower than those of the sn89 calibration, and that the difference is due to the fact that the two calibrations are based on the same set of stars with multiple  measurements, which are treated as separate objects in the cayrel de strobel Metallicity catalog. when the distributions of the residuals ( i.e., @xmath2_{spec } -    _{phot}}$ ) for the ml 02 and sn89 calibrations were compared, the former was found to be most accurate.
event shape variables describe the energy and momentum flow in high energy collisions.   being collinear and infrared safe they can be computed with high accuracy in qcd so that they generally allow a good measurement of @xmath1, and they are sensitive to extra soft non perturbative emissions, so that them prove to be a powerful tool to study the up to now fairly unknown low energy domain. here   we present a new method for the calculation of 3-jet observables in deep inelastic scattering ( dis ) processes. at first order, i.e. when only 2 final state partons are present, momentum conservation ensures that the event is planar so that the observable vanishes. at second order, where vetoing real emissions gives rise to a large mismatch between real and virtual contributions, the observables are selected by imposing a lower bound for the 2-jet resolution variable@xmath11. at double- ( dl ) and single logarithmic ( sl ) level,   the probabilistic answer is quite straightforward : vetoing radiation from any of the 3 emitting partons gives riseto a sudakov exponent which is convoluted with the incoming parton density @x
the orion bn / kl region is a site of intense molecular outflow activity associated with powerful sio masers that can be imaged with angular resolutions much smaller than the stellar disk.   we have used single dish polarimetry and high resolution vlbi imaging to study the origin of the sio maser emission from these objects at the early stages of their evolution. in some cases,   the emission is redshifted to the nw - se direction by a bipolar conical outflow oriented in the direction of the larger co outflow, but in others it is blue - shifted to the se - nw direction, opposite the weak polarity of the outflow. here  , we show that this conflict can be accommodated by using a combination of limb brightening effects on the conical surfaces of the emission cone and an adjustment of the radial velocities of the two types of outflow along the cone's length. for @xmath1, the wt - se outflow was found to be bipolar in direction, but not bipolar in shape, and the redshifting of the emitted sio emission was consistent with a strong bipolar outflow originating from the
the interaction of surface plasmon polaritons ( spps ) with sub - wavelength defects on a metal surface is of great interest from a theoretical standpoint.   we present a systematic comparison between the different scattering coefficients and provide both analytical expressions and qualitative explanations. in a previous work we presented such a comparison@xcite but within an approximate numerical scheme. within that framework   it was found that ridges and grooves exhibited the same scattering, whenever they are shallow enough. here we will revise that result, which turns out to be valid only for long ( elongated ) defects. in this paper   our results show that, as in the previous work, long asymmetric ridges or grooves with the width much larger than the depth do scatter very similarly. however square shallow defects manifest a different scattering efficiency, differing in the relative radiative loss and radiation pattern. using a discretization method, which does not assume the previous approximation, we find that the scattering properties of short and shallow symmetric defects are gradually transformed into the scattering property of elongated defects, as the aspect ratio of the defect increases.
we perform a comprehensive analysis of the multifractal spectrum of fluctuations of the interplanetary magnetic field strength measured at different heliocentric distances and heliographic latitudes during two solar minima ( 1997 - 1998, 2007 - 2008 ) and a solar maximum ( 1999 - 2001 ).   the selected data cover a radial range between 1.5 and 5.4 au and a heliolatitude range between @xmath4 and@xmath5.4 in the solar cycle.    the results show that the slow wind is generally less intermittent than the fast wind for both wind speed and magnetic field components ; however, the intensity of intermittency increases with increasing radial distance from the sun. on the other hand, the fast winds are generally more intermittent than their slow counterparts at all distances studied by @xcite, as compared with the slow winds.
the following is a description of the spectral range of the rass spectrometer ( rass ) used for the first time in the study of the efoscopy of the cephalosarcoma nucleus.   the spectrum was obtained by using the eso / mpi 2.2 m and dutch optical coherence tomography ( oct ) at 1.54 m and 0.9 m resolution with a wavelength of 8.8 cm2.
abstractthe present review focuses on the relevance of storage - ring electron - ion experiments for astrophysics.   the influence of low - energy dielectronic recombination ( dr ) resonances on electron - ions recombination rate coefficients in low - density plasmas and recent efforts to build a recombination data base for astrophysical modeling of photoionized plamas are briefly discussed. finally, a compilation of experimental results for the astrophysically most abundant ions is presented.
we present a simple three - species driven diffusive model exhibiting phase separation and spontaneous breaking of the translational symmetry on a ring.   the model is driven by an external field and the local dynamics obey detailed balance with respect to a long - range asymmetric ( chiral ) hamiltonian. in the case of equal number of particles of each type,   all local dynamical moves that obey the conservation laws are non zero. using this model, we have found the steady state of the model exactly and have been able to prove the existence of phase separation analytically.
the dynamics of fluctuations in a stable bose - einstein condensation ( bec ) of atomic gases is described by using the parametric approximation employed in the description of quantum effects on curve crossing.   the fluctuations are treated here by a linearization of the exact quantum equations of motion for the field operators. in the case of a stable bec,   these equations describe the motion of quantum oscillators, corresponding to the bogolubov quasiparticles. in an unstable bec, however, the equations describe inverted oscillators that grow rapidly, leading to a rapid growth of the fluctuations. this growth remains super - exponential as long as the fluctuations do not reach a macroscopic occupation. at the low occupations of the experiment, the fluctuations can be described as a quantum process of spontaneous decay of the condensate into the fluctuation vacuum, accompanied by the formation of entangled pairs. at high occupations, the transitions between the two - mode squeezed states are more complex, and the degeneration of the entangled pairs is faster than the dissolution of the condensed condensates.
the phase separation phenomenon involving superconducting states ( ss ) is a very current topic after it has been evidenced in a broad range of intensely investigated materials including iron pnictides, cuprates and organic conductors.   the penson - kolb - hubbard ( pkh ) model is one of the conceptually simplest phenomenological models for studying correlations and for description of superconductivity in narrow - band systems with short - range, almost unretarded pairing  . the pkh model includes also a nonlocal pairing mechanism ( the intersite pair hopping term @xmath9 ) that is distinct from the on - site interaction@xmath10 in the attractive hubbard model and that is the driving force of pair formation and also of their condensation. in this paper   we determine the phase diagrams ( for @x Math0 as well as @xMath1 ) of the p kh model for two dimensional ( 2d ) square lattice within hartree - fock mean - field ( hf  mf ) theory focusing on a behavior of superconductor - insulator phases with changing model parameters and on a possibility of the occurrence of the state with phase separation.we obtain
abstractthe formation of galactic disks occurs because gas with net angular momentum is accreted into a potential well before forming stars.   the accretion can occur in two forms, where the gas is either at the temperature of the potential well ( hot ) or well below that temperature. here  , we use high - resolution spectroscopy to study the metallicity of the halo gas around an edge - on galaxy, ngc 891, which is projected 5 kpc from the galactic plane in the inner part of the galaxy. using the modular spectrograph on the mdm 2.4-m hilt and stis telescope, we measure the column density of metal lines in the h Halo gas by measuring the mass of the metal lines as they move along the visible spectrum of the background agn. for the first time, we show that the column densities of the gas are measured by means of the high - performance liquid chromatography / mass spectrometry ( hst / stis ) method, and the results are compared with those of previous studies using the x - ray emitting component analysis of the milky way @xcite. while most of the gaseous gas in the
the problem of finding the optimal solution of a multi - unit combinatorial auction is a hard problem, i.e., it requires extensive resources.   it is therefore essential that one designs carefully the algorithm and uses the available resources smartly. in this work   we propose to use a depth - first search technique based on the branch - and - bound search technique developed by operations researchers  @xcite for finding the best ordering heuristics for multi - Unit Combinatorial Auction problems. using this technique  , we show that the most efficient way to find the optimal allocation of the items is to start with a partial solution of the problem and then backtrack through the entire search space until we find a bid that can be added to the partial solution without creating a conflict and if there is none, know we have attained a possible solution and backtrack again. as a proof of principle, we test the algorithm on a set of bids for a series of commodities and find that it works well.
the first goes x - class flare was observed by the _ hinode_ satellite on december 13, 2006.   the solar optical telescope ( sot ) successfully obtained the photospheric vector magnetograms before and after the flare @xcite, allowing us to study the evolution of the magnetic fields during the course of the flare. in this article   we will discuss the acceleration site and mechanism of electrons from the _ reuven ramaty high energy solar spectroscopic imager ( _ rhessi ) and the nobeyama radio polarimeters ( norp ) images taken during the flare, and compare them with the data from the other instruments.
we have proposed a model for the electroweak baryogenesis, the origin of tiny neutrino masses, and the dark matter ( dm ) based on a supersymmetric ( susy ) su(2)@xmath0 gauge theory with confinement.   we have introduced a benchmark scenario and discussed how to test it at future collider experiments.
gold nano   rods of aspect ratios 4 and 5 were synthesized using a seed  mediated synthesis of cetyltrimethylammonium ( cta ) bromide ( ctab ) stablized gold nano  particles.   they were scanned with scanning electron microscopy ( sem ) and helium ion microscope ( him ). in both imaging modes   the nanoscale structure of the nano  particle shell is revealed by comparing core and shell images obtained with sem and him. for the first time  , we show that the thickness of the cta layer can be measured with sufficient accuracy reducing the necessity for more elaborate measurement strategies such as small angle x  ray scattering ( saxs ) and transmission electron microscopic ( tem ) measurements.
the gene interaction networks of the human cells are known to have important role in cellular cycles including cell development, proliferation, apoptosis and disease.   the high - throughput experimental studies on cancer cells provide huge molecular interaction networks which include 20,000 to two million elements from a single assay. by using the data obtained from several different microarray experiments on specific cancer cells, one may investigate some typical gene interactions in the transcripts network of the cancer under study. in this paper, we have developed a new web - based database of the gene interactions between genes in the protein - protein interaction networks called scale free network ( @xmath0 ) which is based on the mutual information ( aracne ) and the bayesian inference ( sign - bn ) algorithms. as a result of the analysis of the scale free behavior of the network,   it has been found that there are very few nodes which obey asymptotical powerlaw behavior. among them, the most of the nodes are hubs which are highly correlated with each other and they have the same degree of degree of freedom. also, the distribution of the degree of variance of the hubs is similar to that of the scales free network. for example, the hub
@xcite reported the results of the second flight of the medium scale anisotropy measurement ( msam1 ) in 1994.   the observations were compared with the results from the first flight of this instrument in 1992, and a conclusion was reached that there was good qualitative agreement between the two flights in the double difference data set, and that agreement was inconclusive for the single difference dataSet.    this letter presents a quantitative comparison of the two data sets using a range of statistical methods. to account for the small offset drift introduced by the removal of the far - sidelobe response  , the 1992 data is reanalyzed using a procedure nearly identical to that of @xcite s paper  . the 1994 data are also reanalysised, with differences from the original analysis noted in the previous paper. at the same time, the two datasets are compared for their ability to discriminate among early universe models and to determine fundamental cosmological parameters.
the origin of the observed magnetic fields in galaxies and clusters of galaxies, which are of the order of a microgauss in strength, can be explained by an amplification of pre - existing weak seed magnetic fields via well established astrophysical processes ( e.g., the dynamo and/or the flux - conserving compression during the gravitational collapse ) accompanying the structure formation.   however, the ultimate origin of such magnetic fields remains largely unknown. here   we propose a new model for the origin of these magnetic fields, which is based on the idea that they were generated by an abelian anomaly in the action of the helical magnetic field in the primordial plasma, which leads to the generation of the hypercharge magnetic fields at the beginning of the universe, which in turn give rise to ordinary magnetic fields through the electroweak mixing. as a result, the evolution of the cosmological magnetic fields from weak seed fields to strong seed fields depends on the existence of anomalous transport properties in the chiral plasma, rather than the turbulence effects due to the dissipation of the corresponding magnetic fields.
the generalized voter ( gv ) universality class encompasses a large variety of models possessing two symmetric absorbing states, including the interacting monomer - dimer ( imd ) model with nearest neighbor ( nn ) repulsion on a square lattice, which is an interesting variant of the original ziff - gulari - barshad s catalytic surface - reaction model @xcite.   we here present an extensive simulation study on the imd model with nn repulsion and show that the symmetry breaking ( sb ) order - disorder transition and the active - absorbing phase transition are occurring successively at close but clearly distinct points in the same system. moreover, we find that the sb transition reveals a new _ non - ising _ critical behavior, and that the absorbing transition exhibits a directed percolation ( dp ) - critical behavior. to unify these two types of behavior, continuum field theoretic descriptions unifying these two transitions   were formulated via appropriate langevin equations for the local order parameter field.
the production of heavy mesons near threshold in @xmath0 and@xmath1 collisions with stored polarized beams and internal gas targets offers the rare opportunity to study short  range features of the nucleon   nucleon interaction, at distances where the nucleons start to overlap.   cosy represents a unique environment to perform studies of this kind, in particular measurements of polarization observables in heavy meson production reactions, as emphasized recently by @xcite. for the production of heavier mesons,   Cosy again is in a position to dominate the field in the years to come.
supercooling of a liquid to its melting temperature, @xmath5, results in the formation of a metastable state known as the supercooled liquid.   the viscosity of the super cooled liquid increases in an arrhenius fashion until it is so great that any large scale atomic rearrangement ( flow ) ceases on physically meaningful timescales ( order of   100s ). here   we propose a new structural lengthscale related to structural connectivity in the super Cooled liquid, @xcite. by taking into account the thermodynamic driving force for structural change, we show that the structure factors and radial distribution functions of@xcite do not change upon supercooling to @x Math6, where there is a thermodynamic energy barrier to local rearrangements.    this is consistent with the existence of a long range structural order which is associated with the arrest of the glassy phase transition at @x math6 @xcide.
the yield of charged pions and neutrons produced by the passage of a high energy charged particle through matter is an interesting source of electromagnetic nuclear reactions largely occurring at very small angles.   the present investigation is based on the calculation of the @xmath2 production yield of positive pions from experimental data using the equivalent photon method. for photons above 300 mev   an efficient way to produce pions is via the@xmath0 isobar region, which appears as a prominent peak in the photo - absorption cross sections. here   we explore the validity of various approximations to the flux of equivalent photons in this region, and discuss the assumptions necessary to deduce the yield of these particles from experimentally observed data.. the somewhat unexpected result of this study is that pions are produced primarily above the @Xmath0 wasobar region with the rate of production being much higher than expected.    the results are compared to the equivalents photon method in various limits and provide a guide for the application of this method at higher energies.
the dissipative two - state model of decoherence in open quantum systems has been thoroughly studied in wide regions of the parameter space with diverse methods and techniques since the 80 s @xcite.   here we extend the work in ref.,    beyond the pure dephasing regime and include the full dynamics of the qubit. for this purpose, we derive the exact solution for the reduced density matrix without restriction on the parameters of the model and analyze it in the coherent and incoherent domains and in the crossover regions in between. to study the influence of a nonlinear spin - boson environment on the second spin in the various limits, we demonstrate that it behaves in the weak - coupling limit as a bosonic ( linear ) bath with a resonant spectral structure.
accretion disks around super - massive black holes ( smbhs ) have been predicted to be gravitationally unstable at large radii where they become too cool to resist self - gravity and can collapse to form stars or planets @xcite.   there is now observational evidence that the two rings of young massive stars of size @xmath2 parsec in the centre of our galaxy were formed in situ, confirming the theoretical predictions. in our neighbouring andromeda galaxy ( m31 ),   a population of hot blue stars in a disk or ring of similar size, i.e. with radius of@xmath3 parsec, was recently discovered. here   we discuss what happens with the gaseous accretion disk around a smbh when the disk crosses the boundary of the marginal stability to self - gravitation and forms first stars. in a range of distances from smbh, interestingly centered at ~1 parsec  , creation of first low - mass proto - stars should lead to very rapid accretion on these stars. for the latter, the respective accretion luminosity greatly exceeds the disk radiative cooling, thus heating and puffing the disk up. however, star formation is however continued via
the first generation stars, i.e., population iii ( pop iii ) stars with zero metallicity, form out of primordial material left over from the big bang.   they are believed to produce a significant amount of energy in the ultraviolet ( uv ) and to serve as the main sources to re - ionize the inter - galactic medium ( igm ) at high redshift. however, the direct detection of pop iii signatures in high - redshift galaxies remains a major challenge. here  , we show that the he ii @xmath211640 line from pop iii dominated galaxies is strongly enhanced by the strong recombined he ii@xmath0 line, which is caused by the formation of strong he ii emission from Pop iii stars. using a combination of near - infrared ( nir ) and near - sub - mm spectroscopy, we find that the narrow he ii line ( fwhm @x Math10 a few hundred km s@x math9 ) is a direct footprint of pop 3 + stars in these galaxies. on the other hand, our results also show that some of the galaxies with narrow he 2 + emission have a very low star formation rate ( sfr )
grain boundaries ( gbs ) are topological defects that separate two pieces of pristine hexagonal graphene sheets.   they affect graphene s magnetic, electronic, structural, and mechanical properties more than point defects. in this paper   we investigate trends in structural properties, chemical reactivity and vibrational properties for an ensemble of gbs that are not ideal, but have certain roughness. using density - functional tight - binding ( dftb )  , we find that the grain boundaries tend to increase in roughness over time, and that the number of dangling bonds and reactive sites increases with increasing roughness ; however, the amount of hydrogen atoms on the other edge of the grain boundary decreases with increasing rougher grain boundary. by comparing the results of our simulations with those of experimental data, we show that the strength of the dangling bonds is a major determinant of the roughness of thegrain boundary.
the reconstruction of low @xmath3 charged and neutral hadrons is crucial to characterize the collective properties of the system produced in nucleus - nucleus collisions at the lhc.   we have developed an improved tracking algorithm which reconstructs tracks down to 0.1 gev/@xmath1, using just the three pixel layers, with the modified hit triplet finding and cleaning procedures described here.
we study the many - body statistics of mesoscopic brownian particles in a binary colloidal model system that is governed by pairwise additive nonreciprocal forces and erratic brownian forces.   we characterize the strength of these forces by a scalar parameter @xmath0, which is the ratio of the non Reciprocal to reciprocal forces. using the time - averaged pair- and triplet - correlation functions for particle positions, we develop a microscopic statistical theory based on the multiple - body - smoluchowski equation and the kirkwood superposition approximation as a closure. from the results of our brownian dynamics computer simulations, we find that nonrecIProcity induces distinct nonequilibrium pair correlations, and we also analyze the triplet correlations and the impact of the k Kirkwood superpositions approximation.
we have developed a set of benchmark stars for the gaia - eso stellar spectral library.   these stars are chosen to be the pillars of the calibration of the parameters that will be derived for one billion stars by gaia in the near future. here   we describe the selection criteria, the determination of the effective temperature ( @xmath1 ) and surface gravity (@xmath2 ) and the calculation of the metallicity scale (  ) for these stars from the narval and harps spectroscopic data.. the key aspect of the benchmark stars is that they are determined using fundamental relations, that means, independently from the spectra. for a star to be one of our benchmark stars, we need to know, a priori, its radius, its bolometric flux, its distance and its distance from the equator. for each of these parameters, we also need to obtain very high signal - to - noise and high resolution spectra with good signal -to - noise ratios.    the first set of stars consists of 34 hipparcos stars and covers a wide range of stellar parameters.,the effective temperature is determined from the stefan -
liquid crystals ( lcs ) are the most representative class of room temperature ordered fluids.   they provide an ideal testing ground for fundamental theories of order - disorder transitions and the role of topological defects, which are of crucial importance in all areas of physics as well as in many branches of materials science. here   we demonstrate that when a thin film of lc is spread over a chemically patterned surface, the interfacial deformations emerge spontaneously as a result of the interplay between the lc molecular orientation field and the surface chemistry. by using a combination of optical and chemical techniques, we show that the behaviour of the liquid crystal - fluid interface can be tuned by the presence of external fields, e.g. topographical or chemical patterns, which in turn may affect the nematic ordering at the surface.
the mass loss process of evolved stars is a complex process that involves the formation of dust in the upper atmospheres of the star and the transfer of 50% or more of its initial mass back to the interstellar medium ( ism ).   this process is thought to be driven by temperature fluctuations in the stellar atmosphere, which change the physical conditions in the dust formation region @xcite. using existing centimeter and millimeter wave interferometers, studies of the molecules formed in these winds   have been completed showing more or less spherically symmetric mass loss with acceleration occurring to the outermost regions of the wind where acceleration ceases due to decoupling of the gas from the dust. however, our current understanding of the physics and geometries of the process is limited due to lack of adequate modelling. here   we review the recent advances in our understanding of this process and discuss the implications for the study of the chemical modification of the ism in our own galaxy.
the fidelity of the quantum logic gates performed in trapped - ion quantum computers relies cruitially on the quantum state of the ions collective oscillatory degrees of freedom.   if the purity of this quantum state were to be degraded by the action of external perturbations ( which, given the fact that ions couple to any externally applied electric field, seems quite likely ) then the fidelity of quantum operations naturally will suffer. here   we review the experimental causes of the " heating " of the trapped ions, and investigate alternative schemes for performing quantum logic operations which relax the strict condition of being in the quantum ground states of the phonon modes.
we study low - lying eigenmodes of the gauge covariant laplace operator @xmath0\nonumber\\ & & & \hspace*{-0.7cm}-\triangle\phi_n(x)=\lambda_n\pi_n ( x ) \label{eqn_1}\end{aligned}\ ] with a given lattice configuration in the fundamental representation of @x math2.   we find that the lowest - lying mode of the laplacian is sensitive to the location of its instantons @xcite. here, we introduce a novel low - pass filter based on the profile of the modulus of the lowest mode ( the ` ground state probability density') and show that it can be used as a tool to study the effects of changing boundary conditions on the local properties of the mode.
the proposed double quantum dot ( dqd ) charge qubit relies on having two lateral quantum dots tuned to the @xmath10 transition line of the coulomb blockade stability diagram. along this line  , an electron can move between the dots with no charging energy cost.   the drawback of using charge to build qubits is the high decoherence rates when compared to spin. in this work,   we carry out an analysis of phonon decay in a single- and double - qubit operations involving charge in a Dqd charge qu bit.    we follow the time dependence of the system s reduced density matrix, after tracing out the phonon bath, using the redfield formalism in the born and markov approximations.our results show that decohesion rates for this situation are one to two orders of magnitude weaker than previously estimated. 	 the discrepancy arises mainly due to the use of different spectral functions. our model incorporates realistic geometric features which were lacking in previous calculations. when comparing to recent experimental results, our calculations indicate that phonons are likely not the main source of decoherentity in current dqDqd setups.
the strongly correlated two - dimensional electron gas ( 2deg ) in a perpendicular magnetic field at landau level filling factor @xmath0 is the subject of this work.   the ground state of the 2deg at @x Math0 is ferromagnetic, even with zero zeeman splitting. to deal with the disorder and interactions of the system, we have used the bosonization formalism to project the fermionic interacting hamiltonian into the lowestlandau level of the quantum hall ferromagnet. by using the projection technique,   we have obtained an exact excited eigenstate of the hamiltonians of the two - dimensionally interacting 2deg in a quadratic bosonic framework that is in good agreement with the experimental results.. the spin stiffness of the magnon s dispersion is found to be a measure of the free - energy increment associated with twisting the direction of the spins.
ultraluminous infrared galaxies ( uligs ) are the most luminous galaxies in the universe and their bolometric luminosities are comparable to those of quasars.   the physical origin of the large luminosity of these objects is unknown since the very centers of these galaxy are very heavily obscured by dust and direct observation is not possible. here   we use data from the literature together with starburst models and an sed fitting method to give constraints on the nature of the hidden power source in arp 220, the nearest and best - studied ulig with the recession velocity to the galactic standard of rest, @xmath6. using a population synthesis model of the starburst model of leitherer et al. at far - infrared wavelengths, we find that the ionizing photon fluxes generated by the super - star clusters seen in optical and near - infrared images are not the source of the high bolometric luminescence of arp220, which is completely hidden by dust at those wavelengths. instead, we assume that the central regions of this galaxy are powered by a starburst or an active galactic nucleus ( agn ). for each of these assumptions, we compute bolometric Luminosity and ionizing
the see - saw mechanism of neutrino mass generation is examined in the context of the dynamical generation of right - handed majorana masses.   the spontaneous breaking of these global symmetries is shown to produce massless nambu - goldstone bosons ( ngb s ), which are termed majorons by the original model @xcite. using the yukawa couplings of the right -handed and left - handed neutrinos to the higgs field of the standard model, it is assumed that the majorons will become pseudo - nambus - goldstones ( pngb s ) at least via loop diagrams that involve insertions of the various Yukawa vertices in the presence of the higher order higgs vacuum expectation value ( vev).the results show that the induced png b s are calculable, and that they are a consequence of the explicit breaking of the global symmetry breaking associated with the dirac mass generation.
vilenkin has criticised the use of a new class of asymptotically flat singular instantons in inflationary cosmology.   these instantons possess a singular boundary of zero size, but it was argued in @xcite that quantum fluctuations are well defined in its presence. here   i show that this is not the case. for a generic inflationary potential there exists a one parameter family of finite action solutions to the euclidean field equations, which are the natural deformation of the four sphere solution to pure gravity with a cosmological constant. even though they are solutions of the field equations ( away from the singularity ), they are not stationary points of the action and their action depends linearly on a parameter which governs the strength of thesingularity. therefore they must be treated as constrained instantons. by applying the positive energy theorem to the path integral  , I show that the existence of such instantons removes vilenkin s instability.
the central galaxies of rich clusters often differ from other cluster ellipticals in their morphological and spectroscopic properties, including the presence of strong nebular emission lines and an excess ultraviolet / blue continuum.   these features are more common in clusters selected from x - ray samples, and especially in those which are known to have strong cooling flows. here   we analyse the emission line fluxes of a cluster with a strong cooling flow, abell 2390, using data from the canadian network for observational cosmology ( cnoc1 ) telescope and the france hawaii telescope. by analysing the absorption and emission line ratios of the gas in the centre of the cluster, we show that the mass inflows implied by the cooling flows are at least a factor of 10 less than the star formation rates assumed by the photoionisation model.. the origin of the observed emission line luminosity is likely to be due to inflow of gas from the cooling gas into the core of the galaxy, or to the collision of cold gas clouds within the cooling flow. as the density of the cooled gas increases, the number of nebulae in the central region decreases, and the intensity of the emission lines increases
backward hadron production in p+c interactions has been studied over the past four decades by 19 experiments which have contributed a total amount of more than 3500 data points covering wide areas in projectile momentum, lab angle and lab momentum.   the main aim of these studies is the comparison to and the improvement of hadronic production models which are to be considered as multi - parameter descriptions of the non - calculable sector of the strong interaction with very limited predictive power. here   it is attempted to trace a model - independent way from the basic hadron - nucleon interaction via hadron- nucleus to nucleus - nucleus collisions. this aim needs precision data from a large variety of projectile and target combinations as well as a maximum phase space coverage. as the acceptance of the na49 experiment at the cern sps is limited to lab angles below 45 degrees, it is indicated to use existing backward data in the sps energy range in order to extend the acceptance coverage for the asymmetric proton - nucleus interactions.this requires a careful study of the dependence on cms energy and of the reliability of the results to be used.
the relationship between bell nonlocality and entanglement is far from simple for pure multipartite states.   the violation of bell inequalities is only sufficient criteria for certifying entangler but not a necessary one.. even in the case of two - qubit states, there is a phenomena of hidden nonlocability, which is typified by werner state @xcite.    however this phenomena occurs for mixed states. in this paper  , we will consider pure multiparable states. unlike a pure bipartite state, the relationship between Bell nonlocity and entanlement is more complex for three - qu bit states. for these states,   all bell inequalities are equivalent to clauser - horner - shimony - holt inequality, whereas for pure mixed states, they are only sufficient to distinguish between separable and genuinely entangled states. according to svetlichny s definition, genuine tripartite entanglements and genuine nonlocalities are not equivalent, as there are states which do not violate mermin - ardehali - belinskii - klyshko inequalities but have genuine tri Particle entangement.,1-qu
superconductivity in the presence of ferromagnetism has been shown to co - exist in uge@xmath0 @xcite, zrzn@x Math0 @xaite, and urhge@xcite.   the mechanism responsible for the interplay of these phenomena is still subject to considerable controversy, but some useful information about the properties of these systems can be obtained from a phenomenological approach, based on general symmetry arguments and the ginzburg - landau ( gl ) equations. in the present article  , we study the phase diagram of the localized superconductivity near a domain wall ( dw ) in a general phenomenological model using the gl equations as a function of the internal magnetic induction created by the macroscopic ferromagnetic magnetization. with appropriate boundary conditions, we calculate the critical temperature of the superconducting dw superconductor in an external magnetic field at the interface between the two domains of superconductive uge/zrzn+@xMath0 and uge#@x math0@x maths0.0 + 0.5 x - ray crystalline cuprates that are separated by a small thickness of the wall. while the effective gl
dynamical processes evolving on complex networks are of current interest of research.   it has been conjectured that such slow dynamics can occur only in finite dimensional networks as the consequence of heterogeneity : explicit reaction or purely topological disorder. here   i show further evidences for the agreement of quenched mean - field ( qmf ) and dynamical simulations in case of certain erds - rnyi ( er ) and barabsi - albert ( ba ) graphs, in which a dissortative weighing scheme of the edges of the network is used to suppress the information propagation among hubs. in this paper   the effects of the weighting scheme on the dynamics of the contact process ( cp ) and the epidemic spreading in the susceptible - infected - susceptible ( sis ) model are compared with those of the qm f approximations based on optimal fluctuation theory and simulations of the cp in @xcite. by decreasing the infection rate of the neighbors   a continuous phase transition occurs at some critical point from a state with finite activity density from active to inactive steady state, characterized by non - universal, power - law dynamics.
we study the distributions of collectively jammed ( cj ) states in 2d bidisperse systems of dense amorphous granular materials, structural and colloidal glasses, and other jammed systems.   we find that the probability distribution of collective jammed packing fractions narrows as the system size increases and becomes a @xmath11-function located at@xmath12 in the infinite system - size limit for systems composed of particles that interact via soft, finite - range, purely repulsive, and spherically symmetric potentials. by enumerating nearly all collectively jammed states over a range of packing fractions, we can decompose the probability density into two contributions : the effective frequency ( i.e., effective frequency / effective frequency ratio ) and the effective number of collectively jambed states ; and the likelihood that a given jammed configuration occurs depending on the protocol used to generate it.  also, we show that the probabilities of creating a collectively jammed state vary with the packing fraction of the system.
we explore the possibility of a sequential fourth generation in the minimal supersymmetric standard model ( mssm ).   we find that the mass of the charged higgs boson, @xmath1, is sufficiently heavy to avoid contributing to the z width of the top quark / squark loops, and that the yukawa coupling between the two quarks is sufficient to allow a fourth generation with a sufficiently heavy neutrino to avoid this contribution.
the problem of detecting the symmetries of a curve has been studied extensively, mainly because of its applications in pattern recognition, computer graphics and computer vision.   the goal of the analysis is to find the existence and nature of the shape that needs to be identified, without converting to implicit form. here   we consider a different perspective, where the goal is to deterministically detect the existence or nature of symmetry of the studied curve, using a rational parametrization with integer coefficients. for this purpose, we assume that the input is an exact plane or space curve, and that the geometry of the curve is described by a discrete object, i.e., a plane or a space curve defined by means of a rational parameterization. as a result, we want to determine whether the input curve has any symmetry, and if so, to determine all symmetrized parts of it. since the whole curve is not a control polygon, we do not have a set of control points from which the geometric properties of the measured curve can be derived, we are able to directly address the problem of finding the symmetry of such a curve. in this paper  , we present an algorithm for
we present a new combinatorial tool for the enumeration of the limit shapes of various classes of random partitions, some known and some new.   we use two different notions of convergence to the limit shape, convergence in expectation and convergence in probability, which describe how close the random objects are to the desired limit shape. using this approach, we find that the number of partitions of  @xmath0 with at least one part larger than  = 0.5 can be enumerated for several well known classes of partitions, such as the ensembles of random graphs and the finite groups of random finite groups. however, for many other classes ( e.g.  random integer partitions ) it is not possible to enumerate the number or the size of all the partitions, and the results are often not obtainable by previously known techniques. here   our main emphasis is on the computations of limit shapes for these classes of partitioning sequences, which are neither known nor even conjectured before. when represented geometrically, these partitions tend to have unusually interesting parameters, which illuminate the underlying 0/1 laws of their asymptotic behavior.
identical particle correlations ( hbt ) have been used to study the space - time characteristics of the in heavy - ion collisions   @xcite.   non - identical particle correlations give new insights into collision s dynamics  . such correlations arise from coulomb ( for charged particles ) and strong ( for hadrons ) interactions, which occur after particle s last elastic collision. here   we present the preliminary correlation functions for all combinations of pions, kaons and protons identified in the star time projection chamber ( tpc ) detector   . by dividing the right side of the plots by the left(@xmath32 )  , we obtain the " double " ratios in the @xmath7 direction.the results suggest that the emission mechanisms for opposite charge pion, kaon and proton pairs are the same. however, the opposite - charge kaon - proton correlation function deviates from the theoretical expectation, which suggests that our knowledge of this interaction is incomplete.
the packing density of social aggregations of pelagic fishes ( herring, sprat and mackerel ) has been extensively studied by biologists, mathematicians and physicists.   many models for animal group geometry predict that densities increase as the group size ( in number ) increases, but laboratory observations have shown that packing densities decrease as the school size increases. here  , we review the results of experiments on the packing density and internal structure of large - sized schools of pelegic fishes using high - resolution sonar and echo integration, and discuss the relationship between the dimensions and biomass sizes of the schools.
the influence of impurities on the superconducting state of the cuprates @xmath5-wave superconductors is controversial.   the experimental observation of the high - temperature superconductivity, which many people are nowadays convinced has@xmath6-wave symmetry, seems robust against disorder @xcite. in this paper  , we investigate in more detail how impurity potential is renormalized, using the variational monte carlo method and the gutzwiller - projected bogoliubov - de gennes equation@xcite, and discuss agreement and disagreement with the experiments.
the analysis of linear processes with heavy - tailed i.i.d.   innovations and constant coefficients is very similar to classical ( finite variance ) time series analysis, where notions such as autocovariances and spectral density are defined only in terms of the innovation variance and the innovation variances of the linear process. for the latter,   the term   innovation variance  is used to describe the second order moment structure of the stationary sequence. here  , we present a new statistical estimator for the weighted integrated periodogram based on the classes g(x)\dvt x \in\}$ ] for the limit process of the properly centered and normalized process of a stationary sequence that is independent of the coefficients of thelinear process. using the results of the recent studies on the influence of the fourth moment of the first moment on the power law behavior of non - gaussian time series in the time and frequency domains, we show that the proposed estimator can be used to estimate the spectral density of the underlying stationary sequence and to perform various tests concerning its spectrum.
we investigate magnetization changes caused by magnetoelastic effects in batio@xmath0 ( bto ) based extrinsic multiferroic hybrid structures using both ferromagnetic and ferroelectric materials.   we find that the magnetization jumps observed in these structures can be predicted on the basis of first - principles effective hamiltonian simulations, since the strain state of miscut bto crystals as a function of temperature is determined by means of molecular dynamics ( md ) simulations. to calculate these changes, we first determine the strain states of the overlying ferromagnetic thin film clamped onto the bto substrate using both fe@x Math1co@x math1 ( feco ) and ni@x maths1 ( nf1 ) as ferrom magnetic materials. for each ferroelastic phase of bto,   the volume fraction of the domains in each phase of the crystal is calculated from the corresponding ferro electric field applied to the crystal during the transition between the ferroesilastic phase and the nonuniform strain state induced by the structural phase transitions of the crystalline bto. upon cooling down or warming up the hybrid structure at room temperature, the
we study the effective potentials of bare wilson loops and of their eigenvalues, in the fundamental and adjoint representations of su(2 ) gauge theory, through ab - initio simulations in discretized space - time.   our goal is to shed some light on the validity of the perturbative ansatzes for the effective action, which are used in the construction of effective theories. also, we wish to verify that the ansatz used to parametrize the results obtained in refs.1 and 2 is valid for the full gauge theory.
the h - dibaryon is a doubly strange six - quark state with spin and isospin 0. since its first prediction in 1977 @xcite, it has been the subject of many theoretical and experimental studies as a possible candidate of a strongly bound exotic state.   however, theoretical estimates of its mass have varied widely ranging from deeply bound to unbound, depending on the model or theory used for the calculations@xcite. in the present study, we extract more quantitative information on the h   h interaction by employing the quark cluster model used in ref.@xmath2. here  , we take only flavour singlet scalar meson exchange between the h- and h-dibaryons into account and calculate the effective meson Exchange potential ( emep ) of the h - baryon wave function using the monte carlo method. because the emep depends on the color - magnetic interaction ( cmi ) in the one - gluon - exchange potential ( ogep ), we assume that the cmi plays a key role in determining the properties of the echogenicity of the inter - quink potential.    the results show that the
the rate of convergence of a process in ( , given the metric and underlying structure of the sequence @xmath9, is studied using the technique of tikhomirov @xcite.   we show that it is possible to obtain optimal rates for @x Math30 given ( infinite ) weak dependence, which to the best of our knowledge is new ( excluding special cases as linear processes ). under certain mixing assumptions and a bounded support of the underlying sequence,   the results are consistent with the berry   esseen theorem.
accreting millisecond x - ray pulsars ( amxps ) are known to produce transient radio emission from collimated, compact jets that escape the binary during outbursts.   these jets are important because they provide a source of angular momentum loss of the accreting matter, which may significantly influence the evolution of the neutron star ( ns ) spin. in this work   we compile radio, near - infrared ( nir ) and optical data of four amxp systems and constrain the dominating emission processes from their spectral energy distributions ( seds ) using the estimated interstellar extinction towards each source. for all four systems,   the nir - excess is present above the disc emission at high luminosities, which disappears at low lumosities. however, the radio spectrum of the jet is optically thick at low frequencies, resulting in an approximately flat ( @xmath0 ) spectrum that breaks to one which is Optically thin (@xmath2 ) at some higher frequency.    this break frequency resides close to the mid - infrared regime for bh xbs ( @xcite ) but may be further into the mid-infrared in ns systems ( @xaite ).
this paper presents a way to unknot knots and unlink links in the real projective 3-space @xmath10.   this is done through an extension of the classical notion of descending diagram to diagrams of knots and links in @x math10. by doing some crossing changes on a diagram,   it is possible to obtain a diagram of the unkneft or unlink, starting from an arbitrary diagram, and performing some crossings changes on it. for each of these diagrams we can imagine that the diagram of a knot descends from the initial point all the way ( a@xmath12 coordinate is decreased if @x Math12 is the axis along which we project the knot to the diagram ).    more generally, a link diagram can be unlinked with appropriate crossing changes, by putting different components one above an other ( choosing some order ) and making each component descending as above.. the main results of this paper imply the following theorem : any immersion of a collection of circles to a 3-manifold can be turned by a small regular homotopy into a differentiable embedding.
complex grassmann manifold has found its extensive applications in multiple - input multiple - output ( mimo ) wireless communication.   the normalized volume of hyperball in complex grassmann manifolds is used as the probability of the distance between any two points in complex Grassmann manifold to estimate the sinr in large - scale mu - mimo communication systems. in this paper,   precise normalized volume formulas of hyper ball based on two general distance definitions ( projective - frobenius norm and projective-2 norm ) are obtained by applying the probability density function of canonical angle between any point in complexgrassmann manifold and a point in the eigenspace of the wireless channel matrix. for each user, the normalized hyperball volume is calculated as the sum of the mean sinr of each user in single - user mimo ( su - mimO ) mode and the real sinr at each receiver side compared to the sinrs of su - mimic mode. using the results of simulation studies, it is shown that the proposed formulas have very high accuracy and can be used effectively to predict the sin r of mu - Mimo in practical systems.
the geometric phase is an interesting example of a concept in quantum theory.   we analyze the behaviour of two geometric phases for mixed states  uhlmann s phase and the inequivalent @xcite interferometric phase  in the kitaev chain, which is a simple model that can undergo a topological phase transition. for the uhlmanngp geometric phase, we find a behaviour that is surprisingly intricate ; however, we argue that the behaviour is not really tied to the physics we want to capture. in contrast, the interferometry geometric phase adopts a more complex topological character and makes a discrete jump when the multiplicity of the spectrum of the state changes. in our calculation, this translates into a jump at the site where the band gap closes in the Kitaev chains.
we propose a new model for the orphan tev @xmath0-ray ( otg ) flare of 1es 1959 + 650 in the framework of the synchrotron self - compton ( ssc ) model.   the model is based on the assumption that the observed time delay between the primary and otg flares is due to the decay of charged pions in the jet, which is reflected by a plasma cloud with scattering depth located in the direction of the jet propagation. as the jet approaches the central black hole,   a large number of neutral pions decay into @x Math0-rays, which are expected to be observed as tev@xmath1-rays.. the observed timescale of the observed otg flare is found to be about 2.5 days after the predicted time delay from the primary flare to the orphan flare, and the calculated neutrino spectrum shows that the modeled time delay is much longer than the actual time delay of ~2.5 years. using the proposed model, we find that the origin of the orphan tweets can be explained by the effect of the proton density in the jets and the hadronic jet power.
analog network coding ( anc ) is a capacity - achieving strategy in some communication scenarios, where each relay node merely amplifies and forwards its received signal to the maximum level possible subject to its transmit power constraint.   we show in @xcite that the achievable rate of analog network coding in layered relay networks can be approximated asymptotically within a constant gap from the cut - set upper bound of the source power constraints under the following assumptions : ( a ) each relay nodes scales the received signal scaling factor to the highest level possible ; ( b ) the nodes in all layers operate in the high - snr regime ; and ( c ) the source communicates with the destination over any number of layers of relay nodes. in this paper  , we introduce a new approach to reduce the computational complexity of approximating the optimal anc rate in general layered networks based on the notion of network simplification. using the proposed approach, we show that in the gaussian @xmath1-relay diamond network and a class of symmetric layered networks, the network Simplification allows us to maintain achievable rates within small additive and multiplicative gaps of the maximum anc Rate achievable when all relays in a layer
the naive factorization assumption ( fa ) does not apply to exclusive @xmath6 meson decays into charmonia, such as @x Math7 @xcite, for which predictions from fa are always small due to the vanishing wilson coefficient.   it has been known that the branching ratios measured by babar recently imply a larger parameter@xmath10, but the data of their branching ratios are usually many times larger than the expectations from fa. in the qcd - improved factorization ( qcdf ) analysis of the @x math16 decays, the large branching ratio leads to a natural conjecture that nonfactorizable contributions, including the vertex and spectator corrections, may play an important role. here   we investigate these corrections to fa using the perturbative qcd ( pqcd ) approach based on the factorization theorem (e)-(d and  from figs.1 and 2, respectively. with the help of the non - relativistic heavy quarkonium bound - state wave functions, we infer the charmonium distribution amplitudes from the results of the experimentally measured branching ratios.
half - metallic ferromagnets have attracted considerable attention during the last decade due to their potential applications in magnetoelectronic devices.   the term " half - metal " was initially introduced by de groot and collaborators in 1983 to denote the peculiar behavior exhibited by a heusler compound : nimnsb @xcite. here   we study using the full  potential nonorthogonal local orbital minimum   orbital minimum basis band structure scheme ( fplo ) of @xmath14 the case of  and  alloys for which the @x Math7 atom belongs to the vth column of the periodical table.    we find that the equilibrium lattice constants for these compounds are determined by first - principles calculations and we show that all four scc, scsi, vc and vsi crystallize in the non - magnetic rocksalt structure.
the @xmath5 galaxy ms1512-cb58 ( hereafter, cb58 ) was recently discovered as a proto - galaxy candidate.   the galaxy was observed as part of the canadian network for observational cosmology ( cnoc ) cluster redshift survey and was found to have @xxmath7 by identification of about a dozen strong absorption lines indicative of young stars. however, the uncertain extinction correction made it difficult to constrain the galaxy age to better than a range of 10400 myr. in this paper   we present data in three additional photometric bands in the infrared : @x Math11, @x math12 and @x maths2@xmath3. these data allow stronger limits to be placed on both the extinction and the age of the stellar populations in this galaxy. using spectral energy distributions of known redshift precursors of the galaxy, we show that the galaxy is likely to be less than 1.5 myr old at the time of its first episode of star formation with a population of stars as young as 10 myr older than the one observed in the galaxy observed in this study., we also explore the possibility of underlying older populations and discuss briefly
modal logics are powerful tools in mathematics and computer science.   they are also widely used in practical applications : in artificial intelligence, modal logic is used to model the knowledge and beliefs of an agent, and for many specific applications, there exist tailor - made variants of modallogics. determining the complexity of a given modal Logic, defined either by the class of considered graphs or via a modal axiom system, has been an active line of research since ladner s seminal work  . however, most complexity results have been on a case - by - case basis, proving results for individual logics both for standard modalLogics and variations like temporal or hybrid logics. here  , we show that for a large class of modals containing many important representatives, we identify _ all cases which have an @xmath0-complete satisfiability problem, and show that the satisfaction problem for _ all _ other non - trivial logics in that class is @x math1-hard. hence these problems avoid the infinitely many complexity classes between @x Math0  and @x maths1, many of which have natural complete problems arising from logical questions.
we study the electron spin relaxation in monolayer mos@xmath0@xcite by the kinetic spin block equation ( ksbe ) approach.   we find that the dyakonov - perel @xcite ( dp ) and elliot - yafet@Xcite ( ey ) mechanisms are the main mechanisms responsible for the inter - valley spin relaxation, while the intravalley dp spin relaxation is due to the intrinsic spin - orbit coupling ( soc ) of the conduction band which is induced by the space inversion asymmetry of the valence band near the k(k@x Math1 ) point. however, the inter- and intra - valley processes including the intrinsic soc of the voxel- and conduction - dependent spin - splitting process are not included in the calculation since they are absent in the isotropic low - energy two - band hamiltonian used in the previous work. moreover, it is found that the intrinsic value of the soc of each valley is not taken into account in the calculated hamiltonians. on the other hand,   the intrinsic strength of the intrinsic spins of both valleys is considered as the main mechanism for the
the large hadron collider ( lhc ) at the tev scale is expected to reveal patterns under which the standard model ( sm ) is likely to be modified at the high energies.   the large extra dimension model, proposed by arkani - hamed, dimopoulos and dvali ( add ) @xcite, circumvents the hierarchy problem by exploiting the geometry of extra spatial dimensions to find a mechanism to lower the planck scale. in this paper   we consider the neutral triple gauge boson production at the Lhc and study how the add model would alter the sm expectation.    the results show that the addition model would lead to a significant increase in the number of neutral tri gauge bosons produced in the final state of the monte carlo process where the sm particles are localised on a @xmath22-brane with negligible tension and only gravity can propagate in the full@xmath11-dimensions as it describes the geometries of the full space time. while the effect of gravity propagating the full @x Math11-Dimensions would be more sensitive to parameters of models with extra - dimensions compared to the triple gaugeboson production,
the neutral gas of high-@xmath18 star - forming galaxies is the major constituent of the universe, but its composition has not been well studied in detail.   we show that the average mass of the neutral gas in these galaxies is significantly higher than that of the galaxy itself, and that it is dominated by molecular gas, the main component of the fuel for star formation. using a combination of optical and infrared spectroscopy, we find that the density of this gas in the hi  21 cm  line is strongly correlated with the redshift at which it was first detected at @xmath19 ( e.g. *???   * ; *???? ), and can be used to infer the cosmological mass density in neutral gas from the emission signals of individual galaxies with known redshifts up to ~1.5 billion years.
the period of enlightenment was a time when spanish physics, which had been lagging behind the level of the rest of europe, was able to recover. however, the political events of the end of the 18th - century, the war of independence, and then the reign of fernando vii ruined the panorama of spanish science.   the goal of the present communication is to analyze the impact of modern ideas concerning energy and the constitution of matter on the textbooks of 19th-century spain.  in particular, we have examined 45 works on general physics at secondary and university education levels, with publication dates from the mid 19th - Century to the early 20th - decade.
microstripline on a polyimide ( kapton@xcite ) flex circuit substrate is used as a microwave interconnect for transmission line arrays printed on flexible circuit board substrates.   the substrate s thermal conductivity is comparable to that of stainless steel and steel in cryogenic coaxial cables, but the cross - section of microstrip lines is small enough to allow very thin conductors to pass through the substrate without increasing the amount of metal. using microwave resonators to evaluate materials properties at 297 and 77k ( room temperature and liquid nitrogen ), we find that the substrate shrinks little between room temperature or 77k while retaining its flexibility. with the exception of the resonator length change with cooling,   there is no apparent bending or other thermally induced stress between the substrate and fully metalized ground plane when the test structure is immersed in liquid nitrogen.
long linear carbon - chain molecules, such as the cyanopolyynes hc@xmath5n, are found to be widespread and abundant in the cold circumstellar and interstellar clouds.   we report the detection in irc+10216 of the next member of this family, hc @xmath0n, which is a quasi - linear triplet with a @x Math7 ground state. unlike the other members of the ` even'chain family,   the abundance decrement between successive species within the even ( or odd ) number of c - atoms families, c@x math13h / c@ xmath15h, is only 4 - 6 @xcite. for the first time, we show that the hccn / hc#@x maths0n abundance ratio is 20 times smaller than the hc*@xMath10n/hccn ratio, whereas the abundances of the three low - energy isomers of hcs are not affected by the presence of rings.
dark matter and dark energy are two of the major puzzles of contemporary cosmology.   so far, the only knowledge of these components refers to their density fraction and to their equation of state, and even on these numbers we still have a large uncertainty. since there is only one unifying dark - matter - energy component, besides baryons, photons and neutrinos, this model is usually referred to as quartessence @xcite.  in this paper we show that for a wide range of values of the parameter @xmath8, silent chaplygin is consistent with several cosmological tests that involve only the background metric mak03b, such as the cmb anisotropies spectrum, the mass power spectrum and the entropy perturbation analysis. using the latest data sets, we review all these tests using a careful treatment, presenting the outcome of a combined analysis of the data for both silent and adiabatic Chaplygin.
the phenomenon of finite - time disentanglement, also named entanglement sudden death ( esd ), unveils a fundamental difference between the global behavior of an entangled system and the local behavior of its constituents under the influence of local decoherence.   it is not clear whether bipartite bound entangled states can be created from free entangled states under local decosherence process naturally. in this paper, we investigate the problem from a very different viewpoint, i.e., in the present of localdecoherence, which is one of the dominant noises during the distribution of entanglements.    we show that such a process indeed exists through an explicit qutrit - qutrito - qubit example and propose the distillability sudden death(dsd ) free state, which has entangler robust against local deconverteption. to build dsd - free states, we develop a few systematic approaches to build quantum systems with dsd-free states. by performing a simple local unitary operation on the initial entangled state,   we find that the first state becomes non - distillable in finite time. however, the second state remains entangled even if the initial state
we have studied the nonlinear dynamics of a finite fermi - pasta - ulam ( fpu ) oscillatory chain in terms of nonlinear normal modes ( nnms ) in the form of weakly coupled nonlinear oscillators ( 2dof ).   we have shown that for low excitation level a slow energy transfer along such chains is realized by spatially periodic waves due to nonlinear resonant interaction between the degenerate nnm corresponding to the same eigenvalue @xcite. as the excitation energy grows the domain of weak localization in one of the oscillators expands and the area between separatrix and the limiting phase trajectory ( lpt ) diminishes up to complete degeneration of latter. at this instant the complete energy exchange is forbidden and the energy becomes confined in the initially excited oscillator, which can be explained by the resonant interactions of the degenerated nnm with the system s stationary nnm.
monte carlo hypothesis test is a useful tool to validate the results of dynamical analysis, and thus help understand the causal processes underlying the experimental data.   this method is often used to explore the possible answers to the following questions : are the data linear or nonlinear, stochastic or deterministic, pseudo - periodic or chaotic?   the focus of this section is to introduce the framework of monte car lo hypothesis test, and to discuss some important concepts associated with the components that form the framework, which will be frequently applied in our later analysis.
the hadronic cascade of drell - yan ( dy ) @xcite is a simple and robust multiscattering scheme for the study of relativistic hadron - hadron collisions.   the cascade is run in two modes, a high energy fast - time stage in which the collisions histories are recorded and only fast processes are allowed to engage. using the entire space - time and energy - momentum history of this fast mode,   a reinitialisation of the cascade can be performed and a second normal hadronic cascading, at greatly reduced energy, carried out. here   we discuss the global time scales which divide the cascade into what one could designate as ` hard ', perturbative partonic or ` soft ', non - perturbation or hadronic, processes.
a simple set of rules, referred to as language or naming games ( ng ), originally proposed in the context of semiotic dynamics, has been studied on various network topologies.   the original model was constructed to account for the emergence of shared vocabularies or conventions in a community of interacting agents. in this paper, we consider and slightly modify a simplified version of the ng, which is based on the concept of pairwise games in which agents perform _ pairwise _ games in order to reach agreement on the name to assign to a _ single _ object. by simulating the agreement process on random geometrical graphs ( rggs ), we show that the probability distribution of the agreement times and the cluster - size distribution in the ng are differentially distributed on regular and complex networks, but not on scale - free networks. furthermore, we present finite - size scaling results for the agreement time distributions in small - world ( sw)-connected rgrs.
we study the effect of a finite isospin chemical potential on the phase diagram of qcd at finite density and temperature in a model ( ladder - qcd ) where the existence of a tricritical point was shown several years ago.   the model is an approximation to qcd based on the evaluation of the effective potential at two - loop level and on a parametrization of the self - energy consistent with the ope results. for the first order transition line ending at the tricritorial point of the case @xmath12, we find that the coupling induced by the instanton interaction between the two flavors might wash out the splitting of the first- and second - order transition lines as in the case of two flavors in the nambu - jona - lasinio model ; however it is not clear if this is the case for the three - flavor case.
the results of the neutrino experiments can be interpreted by two independent mass squared differences ( between three active neutrinos ). from the direct measurement of the invisible part of the decay width of @xmath5 boson ( _ i.e. _, @x math6 ), the number of active neut rinos lighter than @x Math7 found to be @x maths8 @xcite and from the fit of the lep data to standard model prediction it found to Be @xMath9 @xcites.   the existence of almost degenerate sterile neutrines with masses nearly degenerate with the masses of active ones is motivated in many theoretical extensions of the standard model@xcite. for the observational point of view, probing very small values of ~15  mev between sterile and active neutrs needs very long baselines. here   we concentrate on the effects of almostdegenerate sterile neutrinos on the expected flux of cosmic neutrids coming from astrophysical sources. using the new generation of km@xmath17 scale neutrini telescopes, we show that the observed flux of ~2.5  mpc cosmic neutRinos from supernovae remnants
the hubbard model of interacting fermions in a solid is a centerpiece of modern condensed matter physics.   the model has been used to study a wealth of intriguing quantum many - body phenomena that are due to electron correlations in solids, such as interaction - driven insulators @xcite, quantum magnetism and high - temperature superconductivity. however, despite more than a half of century of intensive investigation, the physics of the model is still not completely understood. here   we present a numerical benchmark for the realization of the antiferromagnetic ( afm ) transition and the neutral magnetic ( nel ) state in an ultracold atomic gas - loaded optical lattice emulator of the Hubbard model using the unbiased unbiased thermodynamic ( ust ) approach.. the experimental results show that the ust approach is a reliable and accurate method for the calculation of the nel state in the strongly correlated regime of the half - filled three - dimensional hubbard models on a simple cubic lattice.
we prove that entropy exists for random walks on general free products.   we derive three different formulas for the entropy by using three different techniques. in particular, we study the asymptotic behaviour of the rate of escape with respect to the word length of random walks from a transient markov chain starting at the empty word @xmath10 to the end of the free product @x Math11. when varying the probabilty measure of constant support,   the entropy varies continuously on the probability measure, which governs the random walk. if the limit of the entropy exists, it is called the  non - zero entropy.
we study the time evolution of a relativistic wave packet ( wp ) representing a fermion in the harmonic oscillator potential with spin - orbit coupling.   it is shown that the initial wp is an eigenstate of the spin pointed at some arbitrary direction defined by two numbers @xmath7 and@xmath8 : @x math9 } \,   \pmatrix { \alpha \cr \beta \cr 0 \cr 1 } \cr 2 } \,, \ ] where @x Math10 is the time dependent equation. during one period of this time evolution, the spin collapses ( at the same time the wave function initially pure in both subspaces gets maximum entanglement ) then ( almost ) restores in the opposite direction, collapses again and restores exactly.
the homotopies of the platonic three - manifolds are fundamental for the mathematical analysis of the topology of manifolds  @xcite.   we present a systematic account of the homotopy of platonic manifolds to deck groups and to their harmonic analysis and selection rules. using the new construction of multiply - connected topological orbifolds, we derive topological selection rules for the harmonic analysis of spheres and show that these rules can be used to predict topological correlations between different multipole orders @xmath3 of the cosmic microwave background.
the radial velocity precision of radial velocity measurements as a function of stellar metallicity, effective temperature, and visual magnitude in a sample of 200 metal - poor dwarfs has been refined by means of simulations.   the results show that the precision of the radial velocities of these stars decreases as the effective temperature rises, and is particularly weak around very metals - poor stars (  @xmath6 ).  also, the orbital periods of gas giant planets are more likely to be found around metal - rich stars than around those with moderate metal - enrichment. however, the observed frequency of these planets is not significantly different from the theoretical model of gas giants formation by core accretion, suggesting that the observed correlation could reflect a dependence of migration rates on the amount of metals present in the protoplanetary disk.
we investigate the elasticity of three hexagonal transition metals at high pressure : iron, rhenium, and cobalt using the full - potential linearized - augmented plane - wave method ( lapw ) @xcite with both local density approximation ( lda ) and generalized gradient approximation ( gga ).   the elastic constants, the elastic wave velocities, and the acoustic anisotropy are calculated for hcp iron, cobalt, and rhenia under high pressure using the lapw method. in all three cases the equation - of - state of the hcp phase is found to be a ferromagnetic one, and its elastic constants are determined by comparing the results of our calculations to those of experimental experiments and a central nearest neighbor force model. as a result  , we find that the elastic properties of the materials studied are not significantly different from those of the earth s inner core.
we propose to use the decoherence of a single spin coupled to a disordered spin - chain as a probe for a many - body localized ( mbl ) system.   this model is known to exhibit a transition between a multiple body localized phase and a thermalizing phase as a function of the number of spin operators in the bath. here  , we show that the transitions are not due to fine - tuning but are rather due to an emergent integrability which is encoded in ( quasi- ) local integrals of motion ( liom s ). at low values of @xmath8, the level statistics of the eigenvalue distribution evolve from a wigner - dyson distribution to a poissonian distribution in the mbl phase. at higher values, however, the poissonal distribution returns to a wigneder - dyson distribution.. the change in level statistics is due to the presence of a non - vanishing order - parameter in the water bath, which can be explained by the existence of a quantum coupling to the environment.
the formation of late - type star forming galaxies ( sfgs ) like the milky way has been studied through several complementary approaches.   detailed studies of the ages, metallicities, and kinematics of stellar populations within the Milky way itself afford a unique vantage point for viewing the assembly of such late -type galaxies. in this paper  , we systematically select progenitors of milkyway - like sfg using the stellar mass growth inferred from the evolution of the star forming sequence and analyze their structural evolution.. we use _ hst _ wfc3 near - ir imaging that probes redder rest - frame wavelengths than most previous works and is therefore less sensitive to light from young stars.    our selection provides a quantitative view for stellar mass build up in different radial regimes. 	 we find that the rate of stellar mass increase is proportional to the number of protons that have formed in the region of interest at the time of the observed redshift. as the galaxy grows in mass,   its population increases in size and reaches its maximum mass at the redshift of @xmath4. by contrast, when the universe is at its lowest redshift, the population decreases in size
chemical reaction is one of the most remarkable quantum mechanical phenomena that made biological life possible on earth, which can also be manipulated to discover novel " green " chemistry, and to avoid " toxic " technologies, provided we can understand the reaction microscopically to a certain extent.   however, within the current formalism of chemical kinetics and the laws of thermodynamics, a chemical reaction between two reactant atoms ( for a given chemical potential, temperature, pressure and concentration ) occurs when they collide with each other with enough energy to overcome an arrhenius - type activation energy, to form a(several ) new bond(s )  @xcite. here  , we attempt to go beyond this macroscopic collision - thermodynamic based description by incorporating some microscopic physics ( with respect to atomic energy level spacings ) to understand why and how a chemical reactions proceeds for a particular set of conditions. in particular, we prove the existence of a stronger attraction ( stronger than the usual van der waals ( vdw ) type ) that can be used to understand reasons and ways in which a chemical reacting atom can proceed ( with further assistance from collisions ) by overcoming the electron - electron coulomb repulsion.
multiple sub - giant branches ( sgbs ) have been observed in several globular clusters ( gcs ), including ngc 1851, ngc 362, and ngc 6388.   the presence of a double sgb in these stars is confirmed by spectroscopic analysis of the main sequence turn - off ( msto ) of ngc 7089, which shows a broad spectrum of light - element abundances that is consistent with a split of the sgb around the star's main sequence turning - off. to date, it has been known that many gcs have multiple or broad red - giant branch ( rgb ) populations, but only a few have been shown to have multiple main sequences ( mss ). in this paper   we present detection of the broad ( and most likely split ) Sgbs in five additional milky way gcs : ngc362, ng c 362 ; ngc 5286 ; ng c 5286;ngc 6656 ; ngC 6656+6656 + 6715 ; ngoc 6656-ngc 6715 + 7089 ; n=6388;n=104 ; and n=1851.
the rhic computing facility ( rcf ) is a large scale data processing facility at brookhaven national laboratory ( bnl ) for the relativistic heavy ion collider ( rhic ), a collider dedicated to high - energy nuclear physics experiments.   the rcf provides for the computational needs of the five rhic experiments, including batch, mail, printing and data storage. in this paper  , we describe the development and maintenance of the linux farm, which provides the majority of the cpu power in the rlfc. with the advent of grid - like technology,   our linux farm has begun to investigate, install and support prototypes of software that possess capabilities that are of interest to our users, such as batch services, network file systems, lsf and a rcf - designed batch software.
shell models are dynamical systems representing a simplified version of the spectral navier  stokes or mhd equations for turbulence.   they represent a consistent and relevant alternative approach to the analytical and numerical study of fully developed turbulence. in this paper   we present a brief review of the history of shell models and their application to the study of forced stationary state and intermittency in turbulence, with a brief mention to astrophysical applications.
numerical methods have a wide range of applications in numerous scientific fields. in physics, for instance, these methods are used to obtain approximate solutions of important differential equations such as the diffusion and wave equations. in this article   we attempt to demonstrate how a formalism used to solve partial differential equations in applied mathematics can be employed to further our understanding of known fundamental ideas in physics. using the explicit finite difference method  , we show that the convergence and causality in the explicit method of the schrodinger equation imply the minimum grid interval size to be of the order of compton wavelength.   this is essentially consistent with those obtained in quantum mechanics.
at ultra - high energies ( uhe ), neutrinos can in principle acquire @xmath1 cross sections approaching hadronic levels.   it may therefore be possible to initiate air showers, which would offer a very direct means of probing these new uhe interactions. for the lowest partial wave contribution to the cross section of a point - like particle  , this new physics would violate unitarity. however, two major possibilities have been discussed in the literature for which unitarity bounds need not be violated. in the first, a broken su(3 ) gauge symmetry dual to the unbroken su( 3 ) color gauge group of strong interaction is introduced as the " generation symmetry " such that the three generations of leptons and quarks represent the quantum numbers of this generation symmetry. in this scheme, neut rinos can interact coherently with all partons in the nucleon, resulting in an effective cross section comparable to the geometrical nucleon cross section. here   we show that this model lends itself to experimental verification through shower development altitude statistics, as described by its authors  @xcite. the results of this kind of experiment have important implications for both neutrino astronomy and high energy physics.
the origin of the x - ray emission from the jets of low luminosity radio galaxies is a matter of debate.   we show that the source size and decay time of the flux doubling time for the unresolved core and the hst-1 component of the cosmic microwave background ( ic / cmb ) are characteristic for synchrotron emission, and that the rate of change in the intensity of both components is proportional to the number of new relativistic electrons injected into the jet. using data from five observations of 5ks each on jan16, feb12, mar30, jun08, and jul24, we derive an upper limit to the source sizes and the decay time to constrain the timescale for e@xmath7 losses, and in turn, @xmath1.
the fermion chern - simons field theoretical approach @xcite is used to investigate the fractional quantum hall effect ( fqhe ) at filling fractions with odd - denominators at zero temperature and at finite temperature.   the problem of renormalization of the effective landau level ( ll ) in the mean - field theory is addressed through a fermi liquid approach, in which the magnetic field is treated semi - classically, and the effective mass is introduced as a free parameter. for the fqh states at filling fraction such as @xmath4, @x math5,@xmath6 etc. in which it is possible to obtain the number of filled effective lls by incorporating the effect of fluctuations of the gauge field, the numerical results are compared with exact numerical results on small systems using the first order loop expansion commonly adopted in the literature.
we have observed h@xmath0 in emission in the t dwarf 2massw j1237392 + 652615 ( *???   * herefter 2mass j12 37 + 65 ), identified from the two micron all sky survey @xcite.   this observation is consistent with the hypothesis that magnetic activity is a major source of emission in t dwarfs, and it is at odds with the observed correlation of activity and rotation in late - type ( f - m ) stars, which is supported by the existence of substantial magnetic fields beyond the convective cut - off of spectral type m9.5ve pc 0025 + 0447.
graphene is the only known mono - atomic two - dimensional ( 2d ) crystal with a unique electronic band structure, viz.   the monoatomic sheet of carbon atoms arranged in a honeycomb lattice leads to an electron band structure that displays quite unusual properties. because of its 2d periodic structure graphene is closely related to single wall carbon nanotubes, being in fact a carbon nanosized tube rolled out into a single 2d sheet. until recently   many of the electronic and optical properties of graphene could be explained within a single - particle picture in which electron - electron interactions are completely neglected. here   we review the current state of knowledge on the role of these interactions in the structural and electronic properties of graphene.
the intermittent sliding or stick - slip dynamics of a rough solid cylinder on a rough inclined surface submitted to small controlled perturbations is a fluctuation phenomenon characterized by non - trivial spatiotemporal scaling laws @xcite, and complex critical exponents if the inclination is below the angle of repose. in this paper,   the sliding susceptibility @xmath0 of a metallic cylinder of length ( 5 mm to 11 mm ) placed on a rougher inclined surface is introduced and examined. to obtain this response function  , we performed a class of very time consuming experiments in which we count the number of perturbation on the incline that give origin to a certain number of sliding events of the cylinder.   we find that @x Math0 presents scaling symmetry in a number of physical situations and the origin of this behavior is investigated.
we report the first theoretical study of a controlled phase ( cz ) gate between photonic ( control ) and matter - based ( target ) qubits using active @xmath0 switching.   the cavities are coupled to their respective cavity modes with rabi frequency, and the quantum interference is controlled by the photonic occupation of the cavity via usual jaynes - cummings interaction in the strong coupling and dispersive regime. through an adiabatic process controllable by the switch  , we show that quantum interference allows high reflectivity and optimal photonic confinement of the interaction cavity. through ultra low and relatively fast transfer of excitations between the interaction and storage cavities, we achieve high - fidelity quantum gate performance.
type ii critical collapse is a type ii critical phenomenon in general relativity where a black hole may be formed during the evolution from asymptotically flat initial data where none is present.   it is found in many simple matter systems in spherical symmetry, and also in axisymmetric gravitational waves. here   we examine the global spacetime structure of the critical solution in the spherically symmetric massless scalar field @xcite, where the critical point is either a discretely self - similar ( dss ) or a continuously self - like ( css ) spacetime, and discuss the kinematics of its critical solution kinematically.
the haldane - hubbard model of topological matter is a natural model in which to explore the effects of interactions on the transport coefficients of graphene.   it describes spin-1/2 electrons on the honeycomb lattice, interacting via a local hubbard interaction of strength @xmath0, and describes a topological phase transition between a trivial insulating phase with vanishing transverse conductivity and a quantum hall phase, separated by two critical curves in the @x Math7 plane, intersecting at the crossing points.. the interaction is tunable by changing the strength of the hubbard effect, and can be used to generate new phases depending on the value of its parameters. here   we show that the interaction does not affect the optical longitudinal conductivity, but instead introduces corrections breaking the exact quantization of the non - interacting model, in particular in the vicinity of the critical curves. for the system described in ref.@xcite, these corrections are due to the emergence of a novel, interaction - induced, topology - induced phase, which is independent of the interaction.
we have conducted an initial survey of four ultra - short period catastrophic variables ( polars ) using the infrared array camera on the spitzer space telescope.   we found that all four of the polars show emission in the 38 @xmath0 m region in excess of that produced solely by the white dwarf plus an m or l dwarf, and that the sources of this excess emission are likely cool circumbinary dust that would likely settle into a disk, and/or possibly a t dwarf - like secondary star.
a von krmn flow is generated by two counter - rotating impellers in a cylindrical vessel. at low reynolds number,   the laminar flow is axi - symmetric and divided into two toric recirculation cells separated by an azimuthal shear layer.   its transition to turbulence for various counter - rotations and aspect ratio has been extensively studied theoretically, numerically and experimentally, with smooth or rough ( fitted with blades ) impellers. here   we show that the flow is organized into large scale coherent structures, which are subject to a sequence of eckhaus type instabilities leading to a  fully developed turbulent state " at @xmath11. the first instability is a bifurcation from the stationary and axi- and shearing toric Recirculation cell solution of the averaged navier - stokes equation at@xmath9, which regains the structure of the basic laminationar flow once time averaged. after the second instability, the flow proceeds through plain, modulated or chaotic traveling waves, until it reaches a final turbulent state at ~@x Math11. in this state, the dynamics of the flow
the accuracy with which physical parameters can be determined from spectroscopic data depends upon, amongst other things, the wavelength coverage, spectral resolution and signal - to - noise ratio ( snr ).   the goal of this paper is to determine the accuracy for which physical stellar parameters can been determined from these parameters at a range of sn and resolutions which could realistically be achieved in a _ deep  survey mission. using a large database of synthetic spectra generated from kurucz atmospheric models,   we show that the accuracy of the parametrization models to determine metallicity, effective temperature, surface gravity, alpha abundances, microturbulence velocity and extinction by the interstellar medium is within the range of 95% to 100%. however, the accuracy to determine mass, age and abundances is lower than expected given the size of the sample and the number of spectra to be collected.graphical abstract
the dirac oscillator is a harmonic oscillator potential for relativistic spin 1/2.   it has attracted considerable interest in the last years because of its various physical applications. in this paper  , we extend the work of @xcite and consider the full @xmath2 dirac frequency oscillator. by means of the nikiforov - uvarov method, we find the complete energy spectrum and the corresponding eigenfunction of the model. to the best of our knowledge,   this approach has not been extended to three - dimensional systems with degeneracies of the eigenvalues. as a result, we show that the thermodynamic properties of the system are very different from those of the one - dimensional model. on the other hand, we found that the free energy, the mean energy and the heat capacity of the stationary states are significantly reduced in the case of degenerate eigenfunctions. also, we have shown that the entropy of the kinetic state is much lower than that of the non - degenerate state. finally, we comment on the connection of our results with others in the literature.
boolean networks ( bns ) are a kind of discrete dynamical systems described by logical variables and logical functions.   they are usually called boolean control networks ( bcns ), and they have been paid great attention by biologists and control theory scientists. in our recent paper zou & zhu ( 2014 ), we have proposed the _ decomposition with respect to inputs for bcns, which is just the controllable normal form proposed by cheng, li and qi ( 2010 ) under the regularity assumption on the largest uncontrollable subspace. in this paper, we consider the system decomposition using the linear algebraic representation of bcns in the framework of the state - space analysis method. first, some necessary and sufficient algebraic conditions for the decomposition between the observable normal form and the kalman decomposition form for outputs are proposed. as the graphical condition is satisfied,   a constructive coordinate transformation to realize the decompositions is obtained. then, a method is proposed to reduce the computational burden in realizing the decomposing with respectto outputs. finally, some examples are analyzed with our method.
abstracta decade of extrasolar planet discoveries has shown that the process of planet formation is more complex than originally anticipated.   the leading scenario for the formation of giant planets is the core accretion mechanism, but the timescale required to build - up critical core masses and thus large gaseous envelopes ( @xmath0-@xmath1  yr ) is comparable to the lifetimes of proto - planetary disks. as a result of gravitational interactions with their host disk, the orbits of planets in the terrestrial mass range are predicted to decay on timescales that are short compared to the lifetime of their host stars.. however, recent studies have found that the effective viscosity of the host disk is subject to fluctuations many times its mean value, apparently caused by turbulent density fluctuations in the planet s vicinity. here   we use 3d simulations of magneto - rotational turbulence to investigate the effects of these fluctuations on the orbital motions of the hot jupiters, the micro - lensing planets, and the eccentric giant planets, @xcite and @jupiter, and compare them to the observed secular decay in semimajor axis over the course of the protoplanet s lifetime
3c  66a is a low - frequency peaked bl lac object ( lbl ), and it has been intensively monitored by two webt ( whole earth blazar telescope ) compaigns.   the aim of this study was to investigate the variability, spectral variability and time lag properties of this object with batc @xmath2 schmidt telescope from 2005 january 26 to 2008 october 16. during this period, we observed 3c 66a with a 60/90 cm f/3 sch Schmidt telescope, which is located at xinglong station of national astronomical observatories of china. for the first time  , we found that the optical spectra of 3c / 66a show rapid intra - day variability : the variability amplitude increased with frequency, and all these investigations showed the opticalspectra turns bluer / flatter when the source brightens, although this tendency was strongly dependent on three data points in the study by @xcite. also, the b - r color index seemed to reach its minimum values several days prior to the peak frequency of synchrotron emission ; significant positive correlation between v - r, r - i indices and r magnitudes was detected by@xc
we present a method for computing the laguerre iterate of an approximate eigenvalue of a matrix polynomial using hyman s method.   the method is motivated by the previous work of bini and noferini, gary, and parlett (  ), who proposed a root - finding algorithm to solve the polynomials eigenvalues problem.    we provide robust methods for computing right and left eigenvectors, backward error, and condition estimates. both hessenberg and tridiagonal structures are considered, and it is shown that hyman’s method can be used to compute the eigen values of the two types of structures. in the case of the tridiagonally symmetric structure,   only the second eigenvector can be computed, and the results are compared with those of the linear eigen value problem.
the process of capture of molecules into the chirped resonant rotation of the optical centrifuge ( oc ) is still poorly understood.   this process was only studied numerically or under the constraint that the molecules rotate in a plane perpendicular to the laser propagation axis, which makes it impossible to study the response of a randomly oriented molecular ensemble to the oc pulse. as a result,   the efficiency of the process, i.e. the fraction of molecules captured by the chiral drive, was not analyzed sufficiently. in this work, we use methods in the theory of autoresonance ( ar ) and analysis of the associated phase space dynamics to analyze the resonance capture process of a driven non - linear system exhibiting a sustained phase - locking with a chiral driving frequency. using the single resonance approximation, we show that the rate of resonant capture is reduced to one degree of freedom, and that the energy ladder climbing ar is applicable to many current experimental setups.
we investigate the effects of magnetic field convergence and coulomb collisions on particle acceleration in twisted magnetic flux tube models with and without field convergence near the footpoints of coronal loops.   we find that both conditions have a significant effect on particle motion, with the latter having the largest effect on the rate of acceleration. for a given field strength,   the acceleration efficiencies are best obtained by re - accelerating electrons in the chromosphere where they lose their energy much slower than in the corona due to re - energization by the electric field in the solar flare model.
we investigate the critical behavior of valence - bond - solid ( vbs ) states in quantum spin chains by means of quantum monte carlo ( qmc ) simulation using the continuous - time loop cluster algorithm @xcite.   we investigate the finite size scaling ( fss ) properties of a generalised _ twist _ order parameter for a periodic mixed - spin chain with a unit cell of the form ( @xmath1 ) and also determine the fss properties of the complex - temperature ( fisher ) zeroes of the partition function@xcite, evaluated in a new scheme through knowledge of the qmc transfer matrix. to evaluate the critical exponents for the vbs transitions, we use a lieb - schultz - mattis extension of the spin - operator on the groundstate of the quantum spin chain as an exact order parameter to signal the transition from a low - temperature dimer gap state to a high - temperature vbs state at critical anisotropy at @x Math9. we find that the two - order transition line at a ( constant ) point with a critical endpoint at # 13 followed by a crossover is consistent with nonlinear sigma model predictions.
we study the temperature and polarization dependence of the spin - drag relaxation time ( @xmath0 ) for a two - component cold fermi liquid, where the low - energy spin and charge excitations of interacting fermions are completely decoupled and propagate with different velocities.   we find that the local spin polarization of the liquid within the quantum many - body system is a key factor in determining the relaxation time of the dipole current at the edge of the luttinger liquid. by means of a careful analysis of the low temperature regime  , we obtain a new formula for the temperature- and polarization - dependent relaxation of @x math0, which is completely different from the one previously obtained by a qualitative method for the same system.
we study the properties of branonium systems, namely the mechanism leading to particle production in the world - volume of a probe brane.   we show that particle production may occur in a regime of parametric resonance similar to the one behind the phenomenon of preheating after inflation for @xmath1-brane, leading to an exponential growth of the particle number in the probe s world - volumes. by analyzing the orbital parameters of the system, we determine how the orbitals constrain this mechanism and analyze the possible properties of the resonantly produced particles. also, we study how the trajectory of the probe is modified by compactifying three of the dimensions parallel to the branes, so that a 4-dimensional spacetime with a flat friedmann - robertson - walker geometry is obtained. in this case  , we analyze the effects of hubble expansion on the orbiting parameters and how it modifies the parametric magnetic resonance regime. finally, we explore some of the cosmological applications of these results and relate them to possible final configurations of the System, including stable states or brane - antibrane annihilation.
we recently described a method to perform quantum monte carlo calculations for lattice fermions using an effective hamiltonian, by which the sign problem that is usually encountered in such systems can be avoided.   we also proved that this method leads to an upper bound for the ground - state energy. in this paper  , we show that, in analogy to the method for continuum problems, it is possible to extend the fixed - node monteCarlo ( fnmc ) method for lattices in order to obtain approximate information about the true ground state of the system. in particular, we give a formalism for this method, using the ( theoretical ) results of the f nmc method described in @xcite and some examples of applications of these methods, in comparing our results to those presented by other authors.
we calculate the planetesimal accretion rate of a self - gravitating clump of gas and dust in the protoplanetary disk as a function of time.   we follow the evolution of this clump using a stellar evolution code developed by one of us ( kovetz ) and compute the mass that is accreted at the beginning of the clump. for the first time  , we find that the process of accretion is faster than expected from the core accretion theory of the local disk instability mechanism. to test the accuracy of our results, we use the same code to calculate the mass of the accreting planetesimals in the early stages of the formation of a jupiter - like planet.    the results show that the accretion rates of the planets formed by the disk instability model are much lower than those estimated from the interior models.
theories with extra dimensions have drawn considerable attention since the original proposal by kaluza and klein.   several new ideas in this context have been proposed and have interesting consequences for particle phenomenology and cosmology. in this paper   we extend the results of the bulk scalar model in five - dimensional rs space - time to arbitrary number of warped dimensions and have obtained the kk decomposition of the scalar kk masses in these multiply warped models. due to the exponential redshift factor in the rs model, kk scalar modes in this spacetime have tev scale mass splitting and inverse tev couplings, whereas in the product spacetimes, they give rise to a large number of light kk modes with a very small coupling with brane fields. in our multiply warped model,   the same calculations have been done in six - dimensional doubly warped spacetime where the spacetime is taken to be a product of a four - dimensional spacetime and a compact manifold of dimension @xmath0. using numerical values for various parameters in our theory, we have also used them to get possible numerical values of low - lying kk mode masses in our multiplying warped model showing explicit
the intrinsic intensity and spectral energy distribution of the interferroni   x - ray absorption band ( iibr ) at the level of the local universe and its evolution with redshift are still a matter of intensive debate.   the @xmath3 opacity of the universe for gev   tev photons is generally increasing with increasing photon energy and with increasing redshift, which can be attributed to the absorption of vhe@xmath1-rays by the iibr. in this review,   we discuss the current state of knowledge about the intrinsic iibr spectrum of the high - frequency - peaked bl  lac objects 1es  1101 - 232 at @x Math25, which has recently been detected as a vhe @x math1-ray source by the h.e.s. array @xcite. based on the constraints described above, we reconstructed the intrinsic vhe ~1.5  @xMath13 m iibr spectra of the hbl1es  1112 - 232 from the observed one, which corresponds to a local photon spectral index of @x maths8. using a combination of density functional theory and quantum mechanics simulations, we show that the peak of
non - collinear and non - coplanar magnetic ordering in models and materials has emerged as an important research topic in recent years.   the reason being the fundamental connection between the nature of magnetic order and electrical properties of various magnetic materials. given that the hubbard model is the fundamental model for magnetism, it is important to know if the unconventional magnetic phases found in the kondo - lattice hamiltonian are also present in thehubbard model. in this work,   we map out the magnetic phase diagram of the Hubbard model on anisotropic triangular lattice within a variational mean - field approach that captures the non - collanear andNon-coplanar magnetism on same footing as the collinearing magnetism. using the density versus interaction phase diagram, we find that a pinball - liquid like charge ordering phase, which has so far been reported in spinless fermion models or multi - orbital models on triangular lattices @xcite, is stabilized by the coulomb interactions at a filling fraction of @xmath2 and occurs concomitantly with either collinears or non - cohen s monte carlo ( mc ) ordered ground states.
we have obtained _ chandra  observations of ngc  6543, also known as the cat s eye nebula.   its diffuse x - ray emission is clearly resolved into several components and shows excellent correspondence with some of the optical features. in addition, a previously unknown point x - rays source is detected at the central star. to understand the physical structure and formation mechanism of this nebula, we have extracted and modeled the spectra of the diffuse x-ray emission from the nebula and compared the distribution of hot gas to the location of the dense, cooler, nebular shell in order to derive the physical conditions of the hot gas.
search for lepton flavor violation ( lfv ) in charged lepton processes is one of the most promising ways to look for physics beyond the standard model.   muon lfV processes are reviewed in the first part, and discussions are given on how we can distinguish different theoretical models. in the second part, a new calculation on the @xmath2 conversion rate is presented including a higgs boson mediated effect in the susy seesaw model.
quasielastic nucleon knockout reactions have been extensively investigated with the aim of obtaining precise information on nuclear structure.   the present work focuses on exclusive proton - induced @xmath8 and@xmath9 processes, whereby the residual @x Math10 nucleus is left in the discrete part of its energy spectrum. using the distorted wave impulse approximation ( dwia ) theoretical framework @xcite, we show that the two - body @x math12 interaction can be approximated by the interpolation of phase shifts from free elastic @x maths12 scattering.    the results are compared with those of previous calculations using a so - called cross - section factorized form of the cross section @xaite.
the hartree  fock scheme of quantum cosmology is a semiclassical approach to the problem of time resolution.   it is not ideal from the perspective of modern cosmology ( which goes as far as second - order perturbations albeit at the classical level ), but it is a start and it has some complementary values. here   i confront the issue that schemes like hh s exclude a lot of the semiclassicals approach s terms. in detail  , i give a term - by - term analysis of these using first toy models of the hh system, such as minisuperspace and relational particle mechanics. for the light subsystem,   I show that averaged correction terms are not always small, and that they can be included in the semi - formalism scheme.. this is a so - called  self - consistent scheme _ of heavily coupled integro - differential equations with a separate variational principle for the heavy subsystem, and a further difficulties in finding a variational principles for the coupled system.    also, i outline how hartrees   fock type theory remains useable and known for its ability to reproduce the structure formation of galaxies and c
the radial - velocity search for planetary companions to stars with masses a fraction of that of the sun presents the obvious advantage that at equal orbital periods, companions of smaller masses can be detected with a given radial velocity precision.   we have carried out a systematic search of all of the stars in the late m, l and t spectral types of the main sequence with a mass of < 65 m@xmath22 using the @xmath0 absorption cell and th - ar comparison lamp methods.    we find no planets of this mass in any of the targets, suggesting that the rate of planet formation around low - mass stars is much lower than predicted by current theories of planet creation.. however, we also find evidence from observations of infrared excesses of very low - Mass stars in star - forming regions that, when young, these objects possess protoplanetary disks at a rate similar to that of more massive stars.
the interplay of mechanical motion and electronic properties has been studied widely in molecular physics and, recently, in molecular electronics and nanomechanical structures.   present - day experimental methods enable the fabrication of nanostructures such as single - molecule junctions or quantum dots where a small number of electrons couple to one or more vibrational modes. at sufficiently strong couplings the sign of the effective charging energy @xmath0 can become negative implying an effectively attractive interaction between electrons. here   we study the opposite regime where the magnitude of the negative ( renormalized ) charging energy exceeds the single - particle level spacing for a single - electron transistor ( set ) whose center island is coupled to a mechanical vibration. it is shown that the system becomes unstable towards addition or extraction of electrons. assuming that the vibron hamiltonian contains an anharmonic contribution we show that the instability is regularized and that the systems possesses a well defined ground state.. the effective charged energy as a function of the electron number in the dot has a double - well structure which, moreover, depends on temperature.    this is in striking contrast to the usual parabolic charging energy and leads to a variety of novel effects.
the new wide field camera 3 ( wfc3 ) was successfully installed during the _ hubble servicing mission 4 ( sm4, may 12 - 24 2009 ).   after a period of intense testing, fine - tuning, and basic calibration, the first calibration- and science - demonstration images were finally made public last september 9th, 2009. since the results of these efforts might have some immediate public utility ( e.g.  relative astrometry in general, stacking of images, uv - identification of x - counterparts such as pulsars and cvs in globular clusters, etc. ), we undertook a study to determine the geometric distortion ( gd ) solutions of the three bluest broad - band filters ( with the exception of f218w ) : f225w, f275w, and f336w. using the @xmath1  cen data set used here, we found that the gd solutions of all three filters are within the range of 0.2 - 0.5  d for the whole dataset, and that the best correction is obtained for the filter f220w, which is relatively redder than the other two.
relativistic jets are highly collimated in both galactic and extragalactic objects.   the k - h instability of supermagnetosonic and trans - alfvnic jets has been extensively investigated in the supermagnetic limit, and the structural and stability properties of these jets have been studied in detail. here   we consider the types of organized structure and stability characteristics that exist on supermagnetsonic and non - relativists jets, respectively. for a jet with uniform density, temperature and axial magnetic field ( top hat profile ) and a uniform external medium, the propagation and growth or damping of the fourier components is described by a dispersion relation. when the flow is supermagneous, the growth rate of normal mode surface and body waves has a maximum that is inversely proportional to the magnetosonic mach number at a wavelength that is approximately proportional to an increase in the magneto - helical magnetic field number. if the jet is subsonic, the poloidally magnetized jet is predicted to be nearly completely stabilized to the kelvin - helmholtz instability when the jet speed is sub - alFvnic ; however, if the velocity is super
the ultracompact binary stars v407 vul ( rx j1914.4 + 2456, *?????   * ; *???,v407 vul and hm cnc are both members of the interacting binary white dwarf ( am cvn ) class.   each system is characterized by a single photometric period, presumed in both cases to be the orbital period. for both systems,   the observed periods are consistent with an accretion - driven flow of accretion material from the impact point of the primary star into the equatorial region of the secondary star. here   we investigate the physical nature of the accretion stream using the method of smoothed particle hydrodynamics ( sph ) and find that it is likely to be driven by a low - energy plasmonic flow that is advected and thermalized below the photosphere of the main star, and thus can be emitted " downstream" of the impact spot in the flow that should develop.
the ultrastrong coupling regime of a superconducting qubit - cavity system interacting with a single harmonic oscillator is one of the most important features of circuit - qed experiments.   the dynamics of the system is very fast and the usual approximations such as the rotating wave approximation ( rwa ) in the jaynes - cummings model break down. from the experimental point of view   it would seem unfeasible to probe a physics that takes place at speeds of about ghz, while the typical measurement apparatus in circuit-qed has response times which are much slower, of about 50 ns. in this work   we take the slow route, showing that it is possible to extract valuable information from the fast dynamics of a system with current measurement technologies. by means of repeated measurements  , we show that the detector is able to probe the ground state excitations of the qubit and the cavity and at the same time reveal information of the interaction model. for example, the repeated measurements accumulate information exponentially fast and behave like an anti - zeno effect, in which the qu bit is projected onto its excited state, revealing those ground - stateexcitations that we were looking for
dileptons are clean and penetrating probes for the hot and dense nuclear matter created by the high energy nuclear collisions.   they can be produced during all stages of a heavy ion collision, and their sources are expected to have different contributions to dileption invariant mass spectra. in this paper  , we present the newest star results on dielectron production from 200 gev p+p and au+au collisions, and compare the results with model calculations. at rhic energy,   the result from phenix showed a significant enhancement in mass region 0.3@xmath50.76   gev/@x Math1 @xcite. however, the huge enhancement could not be reproduced by those model calculations which successfully explained sps data @xcitesite-@xcite ; hence, the new results are presented.
hoii is a gas - rich dwarf irregular galaxy on the outskirts of the m81 group.   it was one of the first galaxies outside of the local group to be studied by high - resolution multi - configuration vla h@xmath0i  observations, revealing a complex pattern of interconnected shells and holes. here   we reanalyze the data from puche et al. ( 1992 ), using only the d - array data, and show that interactions between hoii and other dwarf irregular galaxies are not likely to have shaped its large size.
abstractarp  299 is a powerful merging system located at d@xmath3mpc.   we observed arp  299 with _ _ beppo__sax in the context of a project aimed at investigating the starburst - active galactic nucleus ( agn ) connection in relatively nearby systems, where the detection threshold should allow us to detect agn activity even if not dominant. for the first time in this system a strongly absorbed agn ( @xmath7+ergs  s@x Math8 )   was detected, while the system was not resolved, so we were unable to establish in which galaxy the agn resides. here  we present the analysis of the data from both _   chandra _ and xmm-_newton observations, now available from the archives.    we show that the x - ray contours obtained from the _ chandra  acis - i data superimposed on the _ hubble space telescope _ ( hst ) wide field planetary camera  2 ( wfpc2 ) image show that both galaxies in the interactive system are likely to host an agn.
in recent years, several global quantum chromodynamics ( qcd ) analyses of the parton distribution functions ( pdfs ) have been performed using data from hadron colliders such as the tevatron and lhc.   the main purpose of this paper is to investigate the impact of the differential @xmath0-jet cross section data from d0 on the pdfs by performing a next - to - leading order ( nlo ) global analysis. in particular, we are going to investigate how the inclusion of the intrinsic charm quark component in the nucleon can improve the fit of the emc data to the results of the nlo global analysis for the gluon and sea quark pdfs at large transverse photon momenta. also, we will investigate the effect of the older emc measurements of charm structure function @x math1 on the entropy distributions of the proton and compare the results with those gained from the analysis of tevatomistic data.
the origin of the magellanic clouds has been a matter of debate in recent years.   previous studies have suggested that they formed in the outer regions of the local group or as satellite galaxies of the milky way ( mw ). here   we revisit this question by quantifying the torque provided by m31 using the timing argument / two - body limit of the least action principle, given two new pieces of data : the three - dimensional velocities of the lmc - smc - mw system from proper motion measurements and a sample of background qsos ( k1 and k2 ) and the escape velocity of the mw ( k3 and k4 ) are @xmath5 higher than those used in past theoretical modeling of the Magellanic stream ( ms ) and, for the lMC, now approach the escape speed of the Milky way. to test this theory, we show that the latencies of the cloud - m31 system are much longer than those of the ms and that the clouds may have been subject to external torques before entering the environs of the Mw. on the other hand, we find that the time constants of the orbital angular momentum of
the boltzmann - fokker - planck model for the behavior of individuals under the influence of a social field is presented.   it is shown that the most probable behavioral change is given by a vectorial quantity that can be interpreted as  social force _.  in particular, the social force is the derivative ( gradient ) of a potential, which reflects public opinion, social norms and trends, and will be called the  social field.  to obtain this result a new mathematical formulation related to an idea of lewin ( 1951 ) is developed, according to which the behaviorof individuals is guided by a   social field_. this formulation is achieved by a second order taylor approximation of the boltzman - like equations leading to the following diffusion equations :   diffusion equations_ =  the probability distribution of behaviors within a population of individuals with a given number of individuals,   the variance of the behavior,  and  the rate of transition rates. the results of computer simulations are illustrated by computer simulations.
we present an asymptotically - exact calculation of the heat current through a molecular junction, under explicit nonequilibrium conditions manifested by a finite temperature gradient between the two baths to which the molecule is coupled  the electrons in a conduction band and a bosonic bath.   the solution is governed by the smallness of the electron - phonon coupling @xmath0 with respect to the effective energy band of the conductance electrons in the electronic system. for a single molecule adsorbed on a metallic surface, a molecular bridge, and a single - molecule transistor embedded in one of the arms of an aharonov - bohm interferometric interferometer, we find that the heat flow from the hotter bath to the colder one is nonzero at all temperatures. using a master equation approach, which is perturbative in nature, we show that this is due to the fact that the localized fermionic level is taken off - resonance, which breaks the particle - hole symmetry of the problem and adds a linear term to our quadratic hamiltonian.
the large - scale structure ( lss ) of the universe is an excellent probe of cosmological fluctuations as well ascosmological parameters, as proven successfully by the two - degree field galaxy redshift survey ( 2dfgrs ) and the sloan digital sky survey ( sdss ).   however, theory of lss has not reached the point where one can use it for precision cosmology at the level similar to the cosmic microwave background ( cmb ). in order for the lss data to be as powerful as the cmb data, it is crucial that we can predict the l ss power spectrum to 1% accuracy, which is nearly one order of magnitude better than the current precision. here  , we use an alternative approach based on cosmologological perturbation theory ( pt ) to predict the next - to - leading order correction to the linear power spectrum at @xmath4, where non - linearity is still modest and thus pt should perform better than linear theory. using a 3rd - order pt model, we find that the corrections to the power spectrum are accurate enough to within 10% accuracy for most of the cosmologically relevant parameters. with the exception of
the evolution of the evolving star formation rate density ( sfrd ) is a sensitive probe of galaxy formation and evolution.   we use the near - ir selection of the gemini deep deep survey ( gdds, abraham et al., 2004 ) to study directly the evolution of this parameter as a function of stellar mass at the epoch of observation. using the @xmath31\lambda3727 $ spectra of the gdds sample of 207 galaxies, we find that the sfrid decreases from @xmath3 to @x Math3 with respect to the present, and then increases to ~1.5 times faster than the rate of star formation in the same galaxy at low redshift. for the most massive galaxies at @x math11,   the change in sfrad is proportional to the increase in stellar mass over the observed redshift range. by contrast, for the rest of the sample, the decline is due to an increase in the number of active galactic nuclei, which is related to the expansion of the current population of massive galaxies.
the search for the origin of the standard model ( sm ) higgs boson is at the top of the agenda for the next generation of collider experiments. in this letter   we calculate the strong radiative corrections to the@xmath8 process @xmath9 which is the principal background for the associated higgs production (  ) at the tevatron.   the calculation is performed in the limit where @x Math11-quark is massless, and our results indicate that the next - to - leading order ( nlo ) corrections are significant.
the ultrarelativistic quantum molecular dynamics ( urqmd ) model is adopted with an update of the potentials in the mean field part.   the results of the ratios between the yields of charged pions, the various directed and elliptic flows of pion mesons are shown and discussed.
we present a new computer code to follow the evolution of a central star cluster surrounding a massive black hole ( mbh ) over time scales as long as @xmath9years.   the method is based on a monte carlo ( mc ) method based on the pioneering work of hnon @xcite. in its basic form  , it is more or less equivalent to resolving the fokker - planck equation, but with no implicit integration of the diffusion coefficients. for the first time, we show that the rate of captures on orbits with strong emission of gravitational radiation ( hereafter " gr - captures " ) around a kerr bh can be estimated from the results of simulations using the mc method. by comparing the gr - capture rates of different models,   we find that the number of stars captured by the mass - segregation process depends on the size of the cluster and the density of the mbh at the time of simulation. however, if the cluster is large enough, many stars can be captured by both the mass- and density - segregation processes, which are independent of the presence of a mbh. moreover, when the cluster has a large number of compact remnants, the mass segregation process is efficient
the critical temperature of antikaon condensation in newly born hot and neutrino - trapped protoneutron stars is investigated using the finite temperature calculations of ref.@xcite.   the model to compute the equation of state ( eos ) involving @xmath0 condensate at finite temperature is formulated using a relativistic field theoretical model where baryons are interacting by the exchange of mesons, and the hadronic phase is treated as a second order phase transition from hadronic to @x Math0 condensed matter in protoneUTron stars. for the first time  , we show that the threshold density for @x math0 condensation is sensitive to the nuclear eos as well as the strength of the attractive antikon optical potential depth.    the results are discussed in detail.
the theory of symmetric spaces and lie triple systems is reviewed in this paper.   applications of this theory in numerical analysis of differential equations are discussed, which, in turn, can be divided into two parts. in the first part (  3.13.3 )  , we review and discuss the case of matrix polar decompositions, where a matrix is written as a product of a symmetric positive definite matrix and an orthogonal matrix. in order to reduce the implementation costs of numerical methods on lie groups, it is shown that the generalized polar decomposition can be employed in cases where the theory of  @xcite can not be used. by backward error analysis, numerical methods can be thought of as exact flows of nearby vector fields. in this context, the main tools are compositions at the group level, using the flow of the numerical method and the symmetries / reversing symmetry of the vector field. for the second part of  3 (   and beyond ), we consider the application of this theoretical theory to numerical methods for the solution of differential equation of evolution with symmetry and reversing symmetry.
the intercalation of charged and neutral ions into the host material@xcite is a key step in the design of many technologically important electrochemical devices.   the insertion process can be viewed ( at least in some aspects ) as an adsorption of guest particles on the host lattice, which is usually described within the lattice gas model.. however, the host response to the accommodation of the guest species is not negligible. for instance, the insertion induces the stress into the matrix of the host, which may lead to segregation effects or instabilities @xcite. in this study   we investigate the impact of the thermodynamics on the kinetic properties of the chemical diffusion coefficient of the intercalated system using a general thermo - mechanical theory of the stress - composition interaction that accounts for the loading mechanism and the volume dilatation in the course of the structural transitions ( expansion or restructuring ) between the host and the guest. by combining the lg model, describing the configurational transitions, and the linear elasticity theory, we derive an effective chemical potential involving the concentration dependent stress and strain fields. assuming that the diffusion flux is proportional to the gradient of the chemiluminescence potential,
in many materials the lattice structure does not allow all antiferromagnetic bonds to be satisfied simultaneously.   these are known as frustrated antiferromaagnets and display a variety of different phases ranging from rather well - known neel - ordered phases to much less understood exotic phases such as valence bond crystals and spin liquids. in this article   we investigate how well the next level in the hierarchy, @xmath0, can describe a 2d frustrated antifunctional magnet of real physical interest.
we present a new method for finding an optimal quantum code for the correction of non - localized errors in quantum information theory.   the method is not based on knill - laflamme theory, but on a more systematic approach that takes into account the noise of the quantum channels being encoded and decoded. using this approach, we find an optimal code for any given noisy channel with a suitable domain and range, such that it comes as close as possible to the ideal channel on a fixed @xmath9-level system. by applying the method to the five bit code @xcite, we show that up to the critical value of the depolarization probability the best way of using up to five bit encodings is to do no correction at all.
quantum cognition is the name given to the approaches that successfully apply the mathematical formalism of quantum theory in hilbert space to model cognitive phenomena.   we provide an overview of the ` no - go theorems'that hilsbert space imposes to the quantum representation of certain classes of psychological measurements, including those exhibiting question order effects and response replicability, and we show that the born rule of quantum probability is not generally valid in these situations, hence the general tension - reduction ( gtr ) model'is generally non-hilbertian. however, we also observe that the gtr - model is compatible with the operational and realistic framework for cognitive entities and we present an intuitive illustration of how it can be interpreted in cognition.
we present a new analytical approach to the real - time evolution problem for quantum many - body systems, which combines the advantages of perturbation theory and renormalization group theory.   our approach is based on an analogy to canonical perturbative theory in classical mechanics and is applied to a simple exactly solvable model of a quantum dissipative oscillator. using this approach,   we show that efficient and precise numerical solutions of the analytical equations can be obtained, and that the results are in excellent agreement with known results from other approaches.
we give a numerical characterization of the possible @xmath0-triangles of sequentially cohen  macaulay simplicial complexes.   the method that we use is based on a modification of a correspondence between shifted multicomplexes and pure shifted simplified complexes, provided by bjrner, frankl & stanley ( bfs )  . it is shown that the face numbers of the components of the complex are determined by the ratio of the number of faces in each component to the total number of face - numbers in the original complex. using our main result and an observation made by herzog, sharifan & varbaro  , we also show that the betti tables of componentwise linear ideals can be characterized via a new connection to lattice paths.
the parquet equations are a framework for self - consistent determination of the self - energy and the vertex corrections.   they were first proposed in the context of many - body theory, but their practical application has been limited to the single anderson impurity model. with recent advances in computational infrastructure where peta - scale performance has become available,   calculations for lattice models, such as the hubbard model, are now feasible. however, limitations on computer performance and storage are apparently not the sole obstacles for obtaining the solution of theParquet equations. another major barrier is the stability of the solvers. here  , we review the current state of the art in the field of parquet formulations.
ant colony optimization ( aco ) is a new research topic which is studied by many scholars now.   it is essentially a system based on agents that simulate the natural behavior of ants, in which real ants are able to find the shortest route from a food source to their nest, without using visual cues by exploiting pheromone information. among the main problems of aco,   running time is too long and the quality of solution is still low, that are the two main problems.the aim of this paper is to present an algorithm named * local clustering algorithm ( lc * ) to improve the running time of acO@xcite. according to this method, the training set is divided into different classes and aco is allowed to act on each class for each class. then, the data in each class are classified into different groups based on their clustering feature, and the number of cities is reduced by removing the class which is not convergent with the convergence property of k - means clustering algorithms, and updating the centroid of the cluster whose center is nearest to the center of the class. at last, the results of simulations show that the performance of the proposed algorithm is better than that
type ia supernovae ( snia ) are spectacular events that occur in white dwarf stars and are thought to be the result of thermonuclear explosions of degenerate material in the ejecta of a white dwarf star.   although the accepted mechanism for these events is very well established, it is clear that all snia are not the same and that there is significant diversity in both brightness and decay timescale. understanding this diversity has important implications to other branches of astrophysics  in particular to cosmology where inferences about the properties of distant snia play an important role in probing the rate of expansion of the universe. in this work,   monte carlo calculations using methods similar to those of lucy ( 2005 ) are used to investigate aspects of the influence of the 3d structure of snia on their observable properties. while the results show that the observed variation in light curves can be explained by the complexity of the hydrodynamics of the snia explosions, the effects of the three - dimensional structure of the supernova on the observed variability are not fully understood.
we propose a chiral theory as an effective low - energy theory of spin systems explicitly rather than spontaneously by considering doped antiferromagnets on the square lattice.   we show that in the presence of a chern - simons term one can have either one of two scenarios : i)a spin gapped state occurs as the analog of the fractional quantum hall effect ( fqhe ) with its chiral edge states or ii)the system is protected against such spin gagged state.
the general isotropic spin-1 model with nearest neighbor interactions on a @xmath0-dimensional lattice is described by the hamiltonian@xmath1\; ;, where the parameter @x Math2 governs the ratio of the bilinear and biquadratic terms.   the existence of a variety of phases has been demonstrated in the last decade @xcite. here   we show that the ferromagnetic state of the model is disordered for any value of @x math2. within this quantum disordered regime  , however, there could still be several phases. as a further support for the new disordered phase chubukov @xfite is shown by using perturbational calculation on a specially chosen " vacuum " state with nematic long range order and by applying the standard renormalization group method.
the cosmic infrared background ( cirb ) is a large fraction of the energy released in the universe since the recombination epoch.   it consists of radiation emitted by galaxies, intergalactic gas and dust, photon  photon interactions ( @xmath3-ray vs. cmb ) and, possibly, by decaying relic particles. to determine the fir cirb flux level we have mapped four low - cirrus regions at high galactic latitude at the wavelengths of 90, 150, and 180@xmath0 m. here   we report on the point sources ( galaxies ) found in the results of the analysis of the data from the isophot cirb project using the pht22 staring raster map mode with pia ( pht interactive analysis ) version 7.1 and 7.2. for each sky position   the source detection was performed in two steps using data processed to the aap ( astrophysical applications data ) level with piala and the pairwise method. during the first step the detector signal as a function of time   was used to detect the bright end of the cirb population. in the second step the star formation efficiencies of the early universe were measured and the source counts
baryonic rare @xmath7 decays induced by the flavor changing neutral current ( fcnc ) are studied in detail in the framework of the non   universal@xmath0 model developed in @xcite.   the sensitivities of the branching ratio, forward   backward asymmetry, and asymmetry parameters due to the polarization of the @x Math14 and @x math15 baryons on @x maths0 model parameters are investigated in detail. for each decay, the single and double lepton polarization effects, and polarized forward  backward asymmetries are also analyzed.
recent advances in chiral effective field theory ( @xmath0eft ) have their origin in the study of a range of hadron properties in qcd, including nucleon magnetic moments and charge radii, the nucleon sigma commutator, moments of structure functions and the@xmath1-meson mass. here   we investigate the modifications required for the extrapolation of quenched simulation results from lattice qcd using finite - range regularisation ( frr ).   issues with the formulation of eft on a finite volume are also discussed. to perform a fixed - volume extrapolation we consider the modifications to chiral loop integrals at a finite energy scale and perform a truncated taylor - series expansion of the frr. over a wide range of quark masses,   the full qcd corrections of the quenchable magnetic moments are small over the entire range of baryon mass ; however, the convergence properties of the truncated expansion are superior to those of the traditional dimensionally regulated expansion.
underwater shock waves induced by illumination with a nanosecond laser pulse are utilized in various applications including low - invasive medical treatments.   the laser - induced shock wave triggers a sudden motion of a liquid as well as a free surface, which, for instance, results in generation of high - speed microjets applicable for needle - free injection devices @xcite. for the sudden movement of the liquid,   one of the most important quantities is pressure impulse. to the best of the authors knowledge, plasma growth, the expansion process of the shock, and pressure in water have been _ simultaneously _ measured for the first time, using a combined measurement system, in which ultra-high - speed recording systems and pressure sensors are installed. at the same time, we propose a new model of the Shock Wave to rationalize the observations.
we study the interface states in two - dimensional ( 2d ) electron systems with heterogeneous spin - orbit interaction ( soi ), such as a contact of 2d regions with the sois of different kind or strength.   we restrict ourselves by one - band model which is commonly used for 2d electron gas with soi, in contrast to the case of topological insulators where at least two bands are to be taken into account to describe the edge states. using generalized boundary conditions and an effective interface potential, we find that in this system the interfaces exist which are similar to the surface gapless states in 2d topological Insulators as regards chiral spin texture, but they are more sensitive to boundary conditions. depending on the parameters ( such as the ratio of effective masses in adjacent regions and the band - bottom offset at the interface )   the energy of these states can lie either in the forbidden band or in the conduction band for bulk states or in both bands.the dependence of the interface - state spectra on the parameter of the effective interfacial potential is studied within a model, in which the potential contains two components : a spin - independent component and a component arising from the soi at
we present an experimental attempt to verify the existence of a non - monotonic dispersion relation for surface waves in a magnetic fluid.   we use the commercially available magnetic fluid emg 909 ( ferrofluidics ), which is filled into a v - shaped @xcite cylindrical teflon channel of 6 cm diameter and placed on the top of an electromagnet with an iron core. under the influence of an external magnetic field,   the surface of the fluid is deformed at a critical value of the magnetisation leading to a pattern formation of surface waves. using a ccd - camera, we show that the surface deformation is due to a non-monotonic relationship between the surface tension and the magnetic field near the interface between the fluid and the teflin channel. by means of the shadowgraph method, we find that the direction of the surface waves is inversely proportional to the initial magnetic permeability as well as to the saturation of the field.    the effect of the temperature on the surface wave frequency is also shown to be non - linear.
granular media are materials where fluctuations are very large.   when filling a silo with grains, a part of the weight of the grains is supported by the walls of the silo, meaning that the bottom plate only carries an _ apparent weight _ ( @xmath0 ). in this paper  , we propose a simple numerical model which qualitatively captures some features of the above effects. using the scalar arching model,   we show that the stress propagation in granular media is strongly inhomogeneous, and that the strength of the local slip condition can be controlled by the configuration of the stress paths. at the walls, forces on the grain's neighbours   can be modulated by the shape of the granular packing, so that the system can resist to the applied force, and sometimes not, depending on its structure. at other points, however, the system will slip and lose contact with its neighbours opposite to the direction of the shear. these effects can be understood in terms of _ arching.
core collapse supernovae are dominated by neutrinos, therfore many supernova properties may depend on the nature of neutrino - nucleon interactions.   this provides an opportunity to study characteristic symmetries and features of the standard model weak interactions. in this paper, we present simple formulae so that corrections to the boltzmann equation for neutrinuclear transport @xcite can be incorporated into simulations. at high densities,   the corrections from recoil, weak magnetism, strange quarks and single nucleon form factors are important because they affect the density dependent nucleon correlations discussed by@xcite and @xxcite. however, the density dependence of the electron antineutrino absorption cross section is important only at very low densities. here  , we give estimates of the change in emitted electrons and protons from supernova 1987a via their capture on protons and the differences expected between the spectrum of mu and tau antineutsrinos and neutrines.
the dominant loss process affecting ultracold gaseous alkali metal systems is inelastic three - body recombination, a process characterised by collisional events involving three atoms leading to the creation of a single two - atom molecule ( a dimer ).   the binding energy released by the recombination event is retained by the particles as kinetic energy, which is then used to calculate the rate of change of total particle number from the system. in this paper   we extend the truncated wigner formalism for the evolution of the virtual particle background field for an ultraacold bose - einstein condensate system to include three-body recombination events, which modifies the ensemble differential equations describing the dynamics of the realisation of the field. using these modified differential equations, we show that the loss rate of thermal over coherent systems for similar densities increases by a factor of 6 when the temperature is lowered past the critical point @xcite.
monte carlo ( mc ) techniques are increasingly being used in proton therapy to simulate and validate treatment plans @xcite.   mc calculations are more accurate than pencil - beam evaluations, since they take into account detailed microscopic processes and have a better handling of material inhomogeneities in patients. however, computational times associated with mc simulations can be prohibitive. at present, the use of mc is either restricted to institutions that have access to significant computing resources, or reserved for a handful of cases requiring detailed investigation and enhanced accuracy. here   we show that on a nvidia gtx680 card, @xmath6 200 mev proton@xmath1o nuclear events can be computed in 2 s. our results are verified with geant4.9.6p2.
soft gamma repeaters ( sgrs ) are galactic objects that emit short bursts of x - ray and gamma radiation at irregular intervals.   the most luminous sgr flare observed to date was recorded on 27 december 2004, and originated from sgr 1806@xmath120 @xcite. in this work, we extend a search algorithm developed by matone and mrka for gravitational waves ( gws ) associated with sgr qpos by targeting narrow - band, long - duration gw signals associated with soft gamma repeater qpos at the frequency ranges @xmath9khz, @x Math10hz, and @x math11hz.    we find no evidence of a gw signal at any of the energies accessible by past interferometric gravitational wave detectors ; however, we find strong gw emissions at the frequencies of ~1.5 khz, ~6 hz, and ~8 hz in the late time starquake oscillations near the edges of the global alfvn spectral bands @X-2erg, ~7 hz at the edge of the quasiexperimental period, and > 8 hz during the peak flare.
the accurate knowledge of the global metal content of globular clusters ( gcs ), measured by the  ratio, is critical for many astrophysical problems.   the most important one is the existence of an age - metallicity relation and/or a met allicity - galactocentric distance gradient, up to the most distant regions of the galactic halo. in the past years  , a number of indirect indicators have been devised to overcome these problems, but almost all of them are based on integrated parameters that bypass the distance limit also for very far clusters, but they require a very accurate calibration in order to provide the true content in . here   we present a new set of direct calibrations for several indirect metallic indicators, based on detailed abundance analysis of high resolution spectra of more than 160 red giants in 24 gcs, tied to equivalent widths ( ews ) measured on high quality ccd echelle spectra with model atmospheres from the kurucz grid using the same atomic line parameter and the solar model extracted from the same grid used for giant stars. as a first step, we show that the observed photometric
the behavior of the @xmath1 rare earth metals and their compounds under pressure has been discussed for decades, with the volume collapse transition under pressure attracting a great deal of attention. here   we revisit the case of gd, whose volume collapse was reported by hua et al.   ( 2012 ) and equation of state by akella   _ et al. ( 2013 ), and discuss the new information that has been recently reported on the resonant inelastic x -ray scattering and x - ray emission spectra of gD through p@xmath11 and up to 113 gpa.
efficient fault management is an important building block of network operation.   the aim of this paper is to develop an automated healing method that uses statistical learning of measured data and constraint optimization to heal a fault in a network. for this purpose,   a statistical learning approach using logistic regression ( lr ) is proposed that extracts the functional relations between key performance indicators ( kpis ) and radio resource management ( rrm ) parameters and comprises the _ statistical model. the algorithm is iterative with a time resolution of a day, and should therefore converge in a few iterations. to achieve this requirement, a statisticallearning approach usingLogistic regression has been proposed that extract the functional relationships between kpIs and rrm parameters and comprise the _ statistics model.    the performance of the statistical learning automated healing ( slah ) is evaulated on an interference mitigation use case, namely an inter - cell interference coordination ( icic ) problem in a lte network. as a result, better network performance and user quality of service ( qos ) are achieved, including reduced file transfer time ( ftt ), block call rate ( bcr ) and drop call rates ( dcr ).
we propose a quantum processor for quantum computation on distant resonators with the tunable coupling engineering between the superconducting resonator and the quantum bus.   the resonators in our processor are coupled to a common resonator @xmath0 ( acts as a quantum bus ), which is coupled to an xmon transmon qutrit@xmath5, which acts as the quantum qubit. by coupling the bus to a single resonator at different positions, we can construct the quantum state transfer between the two - qubit controlled - phase ( c - phase ) gate and the fock state on the far - away resonator using the same quantum bus as the one - dimensional ( 1d ) superconductor ; however, the quality factor of the resonator has been enhanced to @x Math4, which makes it a good carrier for quantum information processing.graphical abstract
majorana fermions ( mfs ) are exotic particles that have been the subject of theories for more than seven decades without an experimental signature.   recently it has been suggested that these exotic particles can be discovered in condensed matters systems, in particular in topological superconductors ( tscs ). here   we employ scattering theory to investigate interferometers built based on the proximity effect in 2d topological insulators @xcite or semiconducting quantum wires ( qw ) coupled to chiral majorana modes ( @xmath0mms ), which are gapless, charge - neutral edge excitations. by using the inherent particle - hole symmetry ( phs ) as the only constraint to the scattering theory, we show that the presence of majorana states in these systems is robust because of their deep roots in the global properties of bulk states.
we compare observations of well - constrained massive clusters with the predictions of simulations of the standard @xmath1cdm cosmological model.   we find that the projected virial mass of the cluster - mass cdm halos is larger than expected based on the simulations, and that the effective einstein radius for lensing can be exceeded within a substantial radius for this model.
the contribution of polar plumes to the fast solar wind arising from the polar coronal holes has been a subject of debate and controversy.   this paper is a forward modeling investigation of the plasma dynamics of polar Plumes in the extreme ultraviolet ( euv ) emission line spectroheliograms obtained by soho / uvcs on board the soho/ sumer spectrometer. using a doppler dimming technique, we show that the outflow speeds of the solar wind are greater in plumes than in inter - plumes and that the line widths, on which the dopple dimming effect depends, are also smaller in polar plume than in Inter - plume regions. for each of these conditions,   the density ratio of the plume - interplume density ratio changes little in the height range of @xmath5@xmath3 up to @x Math4. as a result, the rate of outflow increases with height, the number of plumes increases and the size of the doublet decreases.. the intensity ratio of both the doublets decreases with height and the frequency of the line shifts increases with increasing height. at the same time, the
the classification of legendrian rational unknots in lens spaces is discussed.   the number of distinct legendrian knots with tight complements is determined via the classification of tight contact structures on solid tori, and the range of the classical invariants realisable by such rational unKnots and the @xmath2-dimensional homotopy invariant of the contact structures containing exceptional knots are determined.. the results are compared with those of the topological classification of Legendrian knots in overtwisted contact manifolds.
the standard candle peak luminosity assumption that is required by most number - brightness tests of gamma - ray bursts ( grbs ) is unphysical.   we seek to eliminate the large threshold effects present in  studies by correcting the observed number of bursts at a given fluence by the trigger efficiency of the detector. using the calculated trigger efficiency in the pioneer venus orbiter ( pvo ) and the catalogue of pvo events@xcite, we test the correction algorithm and find a standard candle energy for cosmological gamma -ray bursts.
we study high - density quark matter based on lattice quantum chromodynamics ( qcd ) in the strong - coupling limit.   we work in the hamiltonian formalism, which is more amenable than the euclidean formalism to perturbation theory and to qualitative study of the ensuing effective theory @xcite. using a bcs - like condensate as a model system, we show that the ground state of qcd at high densities is a dynamical state in which the @xmath3 gauge symmetry is spontaneously broken by a black - hole - like condensed baryon. when the coupling is strong, the breaking is due to the rearrangement of the global symmetries and goldstone bosons, which are not broken by the breaking of the bcs-like condensates. for low - density qcd,   the breaking takes place via the same mechanism as for continuum csc, but with a much stronger transition temperature.
the subfields of artificial intelligence ( ai ) have contributed many formalisms for the declarative modeling and effective solving of problems.   however, there is a need for a universal modeling framework that allows us to declaratively specify problems involving logic, probabilistic reasoning, machine learning and mathematical programming in a simple, uniform, modular and transparent manner. in this paper  , we propose a newdeclarative framework called _ semiring programming _ ( sp ) that is an attempt to fill this gap. as a framework,   sp is set up to allow the modeler to freely choose the logical theory ( syntax and semantics ) and so everything from non - classical logical consequence to real - arithmetic is fair game. together with a semiring and a weight function, a program computes the count, which can be a \{_yes _, _ no _ } answer in sat, a probability in bayesian inference, or a bound in convex optimization. using the count as a proxy for the problem, we show that the usual suspects from ai disciplines, such as sat, csp, bayesian estimation, and convex optimization, can be : ( a ) expressed as a
we investigate the bipartite network of credit relationships between banks and firms that were present in the japanese credit market during the past years of the period of time from 1980 to 2011.   for each year we obtain the credit network and its community structure by using barber s brim algorithm. when the time evolving nature of networks is investigated, it is important to device methods and procedures that are able to track the time evolution of specific communities of the networks also in the presence of uncertainty related to the statistical nature of the community detection process. here   we propose a method which is able to detect and characterize communities of Banks and Firms that have been present in japan for many years. with our approach we detect layers of networked credit relationships @xcite that have existed in the credit market since 1980 and we characterize the communities obtained for different years in terms of the over - expression of attributes of banks and firm concerning ( i ) the regional location of firms, ( ii ) economic sectors of firms ; and ( iii ) the types of banks.
a classical and crucial problem in the analysis of astronomical sky surveys is the morphological classification of detected sources.   we have implemented a star / galaxy multipass classifier that makes use of external and a priori knowledge to find the optimal classification from the individually derived ones, using the seeing ( seeingex ) as an input to the multilayer perceptron - based system. for each potential candidate we have up to four detections, one per filter ;   each detection is fed separately to the artifact classifier, using as input a set of measured morphological parameters, and the outputs are then combined to have the final classification. despite the relatively low number of training cases for many kinds of artifacts, the overall artifact classification rate is around 90%, with no genuine transients misclassified during our real - time scans.
we study the performance gain provided by the joint multi - cell processing ( mcp ) approach to cellular mobile communications, which allows the base stations ( bss ) to jointly decode the received signals of a mobile terminal ( mt ) and relay terminal ( rt ).   we employ the framework of a linear cellular uplink channel presented by wyner in @xcite@xcite, whereby the signal received by the bss is interpreted as the outcome of a time - invariant system with no fading. using this model, we investigate the performance gains provided by combining two cooperation - based technologies that are promising candidates for such a goal : relaying and mcp. focusing on an intra - cell time - division multiple - access ( tdma ) operation and non - fading channels  , we assess the gain providedby the joint mcp approach over the conventional single - cellprocessing scheme by deriving the per - cell sum - rate in the two scenarios.
we investigate the regge trajectories of mesons with higher angular momentum in the light and heavy quark sector  @xcite.   we employ the rainbow - ladder approach, a widely used truncation that preserves the chiral nature of the pion. by applying the bethe  salpeter equation to the one - particle irreducible green s functions, we show that the ground state mass in the vector channel is in good agreement with experimental value for both the scalar and axialvector states.
we analyze the odd - parity perturbations of hairy black holes in a minimally coupled scalar - tensor theory in which all field equations are of the second order.   we show that the rotation of a general class of spherically symmetric, planar and hyperbolic hairy blackholes in asymptotically flat spacetime is not incompatible with the existence of a static black hole in the absence of a scalar field. for this reason,   the symmetry of the solution is not sufficient for the ( gradient ) stability of the black hole equilibrium. by means of the axial   perturbation analysis, we prove the mode stability with respect to general perturbedations in the odd-polar sector.
the quantum sine - gordon model is an integrable model, whose exact solution can be obtained by using the bethe ansatz @xcite.   however, as usual this exact solution does not guarantee a simple calculation of the observables. in this paper   we employ the _ forward - backward _ scheme @xmath0 dimensional scalar field theory based on the flow equation method to study the real time dynamics of the sine-gordon model after a sudden quench of the interaction. with the help of the unitary transformation from the heisenberg equations of motion to the hamiltonian  , we show that the time evolution problem can be extended to long times without secular terms and that the thermalization debate is still relevant even regarding integrability.
brown dwarf companions have been found at separations of 5 - 30 au around sun - like fgkm main - sequence stars.   however, there is a distinct lack of brown dwarf companion detections at small separations to these stars ( the " brown dwarf desert " ) even though their larger reflex motion would be easier to detect than for planets. here   we present the discovery of a brown dwarf orbiting within 4 au of the nearby ukirt faint standard m8 star, lhs 2397a ( fs 129 ) ( @xmath11 yr ) and discuss its implications. using adaptive optics ( ao ) and space - based imaging, we show that the companion is a low mass brown dwarf ( later than m2 ) orbiting around a very faint low mass star ( m8-m9/l / t ) with a dynamical mass of ~1.5 times lower than that of the main sequence star. given the small separation of this system, dynamical masses can be determined in a relatively short period of time ( < 11 yr ), which will help calibrate mass - luminosity isochrone models and the bottom of the Main Sequence.
we investigate the initiation of a strong sunquake during the c7.0 flare of february 17, 2013, which was observed in active region noaa 11675.   we use data from four space instruments : euv observations from sdo / aia @xcite, vector magnetic field measurements from s do / hmi @xcites, integrated soft x - ray emission from goes, and x - rays spectroscopic imaging data from rhessi @xcits.    we find that the sunqu quake is initiated by the first subflare with the initiation point at the flare impulse signal, and the solar photosphere is heated by the high - energy hard x -ray ( hxr ) impulse from the second subflourage. 	 the time - distance analysis shows that the Sunquake is initiated as an expanding circular wave in the hmi dopplergrams filtered in the frequency high range, 5 - 6 mhz, to isolate theSunquake signal from the convective noise. erythema- and temperature - dependent changes in the lower solar atmosphere are observed during the flare, and this is consistent with the theoretical model of the gas dynamics processes
photoacoustic tomography is an emerging imaging technique that combines the good contrast of optical absorption with the resolution of ultrasound images.   this work investigates photoacoustic reconstructions from ultrasound signals recorded at non - equispaced positions on a planar surface using a novel combination of the non - uniform fast fourier transform ( nufft ) and the prior, which we call nedner-nufft. in this paper   we show the applicability and superiority of the ( ned)ner - nuffedt reconstruction formula in three spatial dimensions, compared with standard interpolation fft reconstruction. to easily assess the effect of a given arrangement,   also 2d numerical simulations have been conducted, to support the argumentation. as a reference we use the @xmath0-wave toolbox @xcite with a standard fft implementation of the inversion algorithm.graphical abstract
we investigate the effect of vortex - pair fluctuations on magnetic - flux noise in high - temperature superconductors ( htsc s ) and ultra - thin films ( containing one cuo@xmath0 layer ).   we find that the spectral density of flux noise is governed by the temporal magnetic - field correlation function, which is a function of the temperature dependence of the renormalized interaction between the vortices in the superconducting layers and the time - dependent vortex correlations needed for the calculation of the magnetically - induced correlation function. to test the predictions of berezinskii - kosterlitz - thyless ( bkt ) type theories, we use a generalized approach using a fokker - planck equation to obtain the full space- and time - independent vortex correlations required for the calculations of the magnetic - fields correlation function.the results are compared with those of experiments on very thin films of highly anisotropic compound bi@x math0sr@x maths0cacu@x Math0o@Xmath1 ( bi-2212 ) in the absence of an external magnetic field. at higher frequencies, the same correlation function is also found to govern the contribution of vortex
we have studied the shape and spin of dark matter ( dm ) and gas components in halos obtained from a large non - radiative cosmological gasdynamical simulation.   we find that the shape of both components is similar, with the exception of the baryon fraction in clusters being smaller than that of the dark matter component. using the smoothed particle hydrodynamics ( sph ) method we have found that at redshift @xmath6 the gas component, on average, has a larger spin than the dm. to quantify this similarity we have used a large cluster sample ( more than 10,000 ) of n - body simulations performed on the marenostrum supercomputer at the barcelona supercomputer center using the entropy conserving gadget2 code @xcite. by means of these simulations we have also studied the distribution of spin parameters of dm and gas particles in our numerical clusters.
we study the renormalization of the noncommutative @xmath0 model, i.e., the model without fermionic matter fields, in which local gauge invariance is attained through a composite field that, at least classically, is not dynamical.   the model is renormalizable but the existence of planar and nonplanar graphs with distinct uv behaviors unveils some interesting features. in particular, some graphs in the commutative case, as a consequence of charge conjugation, do not contribute to the uv behavior of the model. however, these graphs are still present in the unbroken phase of the 2 + 1 dimensional model ( massive@xmath2 ) where the basic field is considered as belonging to a fundamental or to the adjoint representation of the gauge group. for the two - dimensional model,   we find that the main contribution of the planar graphs is due to the presence of infrared divergences, which are caused by the infrared / ultraviolet mixing between the ground state and the upper limit of the perturbative series. in the case of the Planar graphs   it is shown that the same is true for the nonPlanar
we report the discovery of 650850 hz quasi - periodic oscillations ( qpo ) from the low mass x - ray binary 4u1608@xmath052.   this is the second atoll source showing 800 hz qpo after 4u1728@x Math034 ( @xcite ), and the second z - source sco x-1 ( van der klis 1996a ; van paradijs et al., 1996a ) to show qpo at 800 and 1100 hz. in this paper   we describe the observations of four atoll sources with a change in mass accretion rate from banana to island state using the proportional counter array on board nasa s rossi x -ray timing explorer ( rxte ; @xaite ) during the decay of an x - rays outburst on march 3, 6, 9 and 12 of 1996.    the source count rate during the observations varied between 2910 and 3400 c / s ( in the pca energy range of 560 kev ), but dropped by a factor of 5 during the first orbit of the last observation due to a change from banana into the island state. for most of these observations,
transistors of nanoscopic sizes fabricated by linking a lithographically defined semiconducting quantum dot to electrodes @xcite are based on the kondo effect. in even smaller transistors,   the current flows through a single molecule. in sec.   , the experimental evidence on the molecular orbital gating obtained by transition - voltage spectroscopy for single - molecule transistors based on 1,8-octanedithiol and 1,4-benzenedithiol ( odt and bdt ) is reviewed. as expected, the linear dependence of the highest occupied molecular orbital ( homo ) energy@xmath0 on the gate potential @xmath1, a key feature demonstrating the homo - mediated transistor function, does not critically depend on the particular model assumed in ref. erythroid@xcite. instead, the observed linear dependence is more general and can be explained by a point - like molecule.
the study of random matrix ensembles has brought in a great deal of insight in several fields of physics ranging from nuclear, atomic and molecular physics to quantum chaos and mesoscopic systems.   recently, it has been realised that the fluctuation properties of low - dimensional systems, e.g. chaotic quantum systems, are universal and can be modelled by an appropriate ensemble of random matrices. with general assumptions about the symmetry properties of the system dictated by quantum physics, random matrix theory ( rmt ) provides remarkably successful predictions for the statistical properties of spectrum, which have been numerically and experimentally verified in the last few decades. in this paper, we show that the empirical correlation matrices that arise in the atmospheric sciences can be used to study the large scale patterns of atmospheric variability as a random matrix chosen from an appropriately selected ensemble. using monte - carlo simulations, we find that the distributions of the eigenvalues of the correlations can be predicted by rmt based on the model of eigenvector distribution. these results are compared with those of the experimental data and the results are consistent with the predictions of the rmt predictions.
a novel framework for track fitting in complex detector systems is presented in this paper.   it organizes the task of track fitting, i.e.  the interplay between fitting algorithms, detector hits, and particles trajectories, with a minimal amount of interfaces. to make optimal use of the information from combinations of all types of tracking detector systems,   the framework provides a well defined interface for the invocation of external programs or libraries to perform track extrapolations.    the concept presented here is independent of specific detector setups and magnetic field geometries and hence can be used for many particle physics experiments.
weather derivatives are contingent contracts whose payments are determined by the difference between some underlying weather measurement and a pre - specified strike value.   they provide a useful risk management tool for any party facing weather risk, and also provide investments which are often uncorrelated with more traditional financial instruments, allowing investors to diversify. in this paper   we consider the use of weather derivatives to provide protection against high impact, low probability business losses caused by extremes in the weather. though not technically insurance, we model losses and price derivatives using actuarial techniques originally developed to price insurance. from the point of view of insurance,   the quantities @xmath21 are the _ pure premiums _ of the contracts. when used to insure crops, weather derivatives help reduce the perceived information asymmetry associated with crop insurance, wherein farmers often have more information about their individual risk than insurers.
the confinement - induced resonance ( cir ) splitting in anisotropic traps in ultracold quantum gases is a well - known phenomenon.   it is a confinement - inducing resonance defined for zero - energy limit when the ground state energy threshold of the colliding pair coincides with the resonance in the closed transverse channel, transverse excitations / deexcitations during the collision, center - of - mass effects, a new mechanism for molecule formation, a cir - splitting at the cir region, anharmonicity effects, three - body effects, and a few - body effect in a confined geometry of a 1d confining trap. to obtain a quantitative description of the mentioned effects has demanded the development of new computational methods that are discussed in the next section.
in this paper we discuss the long distance classical and quantum corrections to the schwarszchild and kerr metrics using the techniques of effective field theory.   we show how the nonanalytic radiative corrections to a particle s energy - momentum tensor can be used to obtain the classical nonlinear terms in these metrics at long distance, and calculate the analogous nonanalytical quantum corrections. for the schwarzschild metric we consider the case of a massive scalar particle. here   it is shown that the spin - independent quantum corrections are the same as those of the scalar particles ; however, some numerical disagreements in related calculations have emerged in the literature.we then present the kerr results, using a massive fermion as a source, and show that the spins of the fermions are also spin -independent.    we also elucidate various theoretical issues and compare with other results in the published literature.
superconductivity ( sc ) of the fe - pnitide superconductors, la(of)feas and ce(of]feas, is strongly correlated with the antiferromagnetic ( afm)-type correlation of their d - electron spin moment.   this study investigates the possible pairing states in these materials using a phenomenological approach. by solving the coupled bcs calculations for the ferromagnetic dipole pairings, we find that the coupling between the fe3 + and fe4 + 3d - electrons is stronger than the interaction between the Fe3 + atoms and the fermi surface ( fs ) at low temperatures.. the strength of the coupling is proportional to the temperature of the superconducting transition below @xmath3 k. the results show that the most likely pairing state is a s - wave type pairing symmetry, which is confirmed by tunneling spectroscopy and neutron - scattering experiments.
the classical field approximation is a simple and convenient technique for describing the dynamics of the bose gas at non - zero temperatures.   we have shown that the whole isolated system may be viewed as a single classical field undergoing nonlinear dynamics leading to a steady state @xcite. in the present paper  , we further corroborate the details and the applicability of the classical fields approximation by applying it to a dynamical dissipative process : the phase imprinting of a vortex on a finite temperature, partially condensed bosegas.. the results show that the method is applicable to the case of a spherically symmetric harmonic trap with periodic boundary conditions.
supersymmetry  ( susy ) is a well - motivated extension of the standard model  ( sm ) that provides an explanation for the stability of the hierarchy between the weak scale and the planck scale.   experiment excludes susy from being an exact symmetry at low energies, but if supersymmetry is softly broken, it is possible to push the superpartner masses up enough to make the theory consistent with experiment while still preserving the electroweak - gravity hierarchy. in the present work   we study the vacuum structure of hens models, and compute the energy - dependent effects of the non - vanishing higgs soft scalar soft terms at the boundary scale on the charge - and - color - breaking  ( ccb ) minimum and unbounded - from - below  ( ufb ) directions of the sm electroweak vacuum. as expected, the results show that the ccb minimum is much larger than the ufb minimum, suggesting that the true vacuum of the theory might be more complex than previously thought. erytheoretical calculations of the quantum gravity field space are also presented, showing that the qcbs can be used to test the existence of uncolored sfermions in the absence of
we study here the computation of waveguides with symmetries which can be a translation, a rotation or a periodicity.   the vibration of such waveguide has been the topic of much research in the last few years and the results from this research have been used to develop computational methods for the calculation of wave propagations and dispersion curves or the determination of the frequency response functions. in this paper   we present a recursive method to calculate the forced response of structures considered as wavesguides. using a finite element model of the cross - sectional deformations of a waveguide  , we find that the global dynamic stiffness matrix of the waveguide can be obtained with a computational cost independent of the number of periods in the structure. by decomposing the rotational and cyclic symmetry into cosine and sine functions   it is possible to find the transfer functions or modal shapes for periodic structures.
the circumburst afterglow ( grb ) is a light - emitting diode ( em ) spectroscopy experiment that uses x - ray diffraction to observe the interaction of two different metals in a clumpy environment.   we have studied the absorption spectra of grb050730 and grb060418 afterglows using uves pipeline for midas, and found seven main absorption systems at z=3.968, 3.564,2.2536, 2.2526, 2-2.2618, 1.7729 and 1.723   with respect to the solar values. both high and low ionization lines are observed in thecircumburst environment, but their relative abundances vary from component to component, indicating a clumping environment consisting of multiple shells. metallicity in grbs can be measured comparing the column densities of heavy elements to that obtained for hydrogen by fitting the ly@xmath5, @xmath6 and @x math7 profiles. both for grb0500730 andgrb050922c  , we find metallicities between @x Math8 and @Xmath9 with respectto the solar
the thermodynamics of the thermal transport properties of the heavy fermion paramagnet ceru@xmath0si@x Math0 in magnetic fields up to 11.5 t and to temperatures down to 0.1k are studied.   we find multiple sign changes in the field dependent thermopower, as well as a large negative peak at the metamagnetic transition ( mmt ) that persists in the low temperature limit. using simple models we can reproduce either the sharp features in transport, or the peak in the electronic specific heat, @xmath4, but not both simultaneously. there is a sharp kink in the energy at the mmt, similar to that seen in the hall effect, which is explained by a lifshitz transition model.
the magnetic field of the quiet solar photosphere has been investigated by @xcite using techniques based on the hanle effect to infer properties about the magnetic field in the quiet sun.   the results suggest that the observed zeeman signals are a result of statistical fluctuations of a quasi - isotropic vector field, which is consistent with the hypothesis that there is a substantial amount of " hidden " magnetic energy in the internetwork regions of thequiet photosphere.
the introduction of random fields into the interaction of quantum systems with a complex background can be simulated via the introduction of stochastic or random fields.   the random fields account for residual interactions with the complex environment or, when it is perturbed by an external field, can be associated with a noisy component in the external field as can happen, for example, in the interaction between a laser and electrons in atoms. using the spin - boson hamiltonian, the authors reformulated the original problem in terms of a sto chastic schrdinger equation with a gaussian noise coupled linearly to the quantum system. here   we present a general method for the calculation of the effective non - hermitian hamiltonians for the dynamics of non - relativistic quantum systems coupled to random fields which is based on the integration of the discrete random fields for the evolution of the quantum state amplitude and the estimation of the fluctuations due to the fluctuation of the random field.the results show that the method is sufficiently general and can be applied in many different types of noisy quantum systems.
the @xmath0-ray emission in blazar jets from the active galactic nuclei ( agn ) of blazars is caused by relativistic jets of highly energized, magnetized plasma that are propelled along the rotational poles of the super - massive black hole ( smbh ) - disk system @xcite.   the location of such emission regions remains one of the greatest current challenges in high - energy astrophysics. here   we present a new model for the @x Math0-rays emitted by these jets using the _ fermi  gamma - ray space telescope ( _ fmri ), which has been launched by nasa in mid 2008 and represents a revolution in time coverage, energy range, sensitivity, and angular resolution with regard to its predecessor, the compton gamma - Ray observatory ( cgro ).. the model shows that the @ x mm jet emission sites are located in the broad line region of agn ( blr ), where the jet s optical  uv photon field is embedded by the blr s optical radiation field that can be scattered to @x maths 0.5 cm2 away from the smbh by relativist electrons in the jet
we derive irreversible master equations for the one body reduced density matrix operator of a weakly interacting bose gas in the weak coupling limit and the markov approximations.   these equations describe the time evolution of the occupation numbers as the bose - einstein condensation ( bec ) transition takes place, taking into account the essential mechanism of atomic collisions that end up equilibrating the system once, say, a evaporative cooling step has been performed.
the string theory plays a significant role in the study of physical situation at the very early stages of the formation of the universe.   it is generally assumed that after the big bang, the universe may have undergone a series of phase transitions as its temperature lowered down below some critical temperature as predicted by grand unified theories. during phase transition the symmetry of the cosmos is broken spontaneously and it can give rise to topologically stable defects such as domain walls, strings and monopoles. in all these three cosmological structures, only cosmic strings have excited the most interesting consequence @xcite because they are believed to give birth to density perturbations which lead to formation of galaxies. here  , we present a new exact solution of string cosmology with and without a source free magnetic field for bianchi type i space - time in the different basic form considered by carminati and mcintosh ( j. r.@xcite@xmath0@excite ).
angular momentum transport in protostellar discs can be transported either radially or vertically, either by turbulent viscosity induced by the magnetorotational instability ( mri ) or by centrifugally driven winds.   quasi - steady models that incorporate both mechanisms have already been attempted, but these studies treated the radial transport using prescriptions that do not account for its origin in mri - induced turbulence. a more refined approach seems needed, however, as solutions in which a wind carries away all the excess angular momentum of the fluid are not susceptible to sustain mri- and/or non - steady modes are needed. here  , we present a wind - driving model that incorporates both radial and vertical transport mechanisms in a solution of a strong magnetic field and a strongly magnetised disc, and show that the latter is the dominant transport mechanism when the magnetic field is strong ( suprathermal ) and the mri is suppressed because the wavelength of the most unstable perturbations exceeds the magnetically reduced disc scale height.
we construct disordered ground states of many - particle systems with special scattering properties using a collective coordinate approach.   we first establish that systematically increasing the system size has no effect on the degree of disorder, and that the constructed configurations remain disordered in the infinite - volume limit. by tuning the scattering characteristics for certain wavelengths, we then construct many - body configurations that give rise to these targeted characteristics : " stealth materials, " " super - ideal gases, " and " equi - luminous materials ". upon generating ensembles of ground - state configurations for each class of materials described above, we characterize local order of each ensemble using pair information in real space via the pair correlation function @xmath0 and in reciprocal space through the structure factor@xmath4.    we find that the structures of the investigated materials are not only disordered but also show local clustering similar to those of polymers and aggregating colloids at low temperature. as a result, we propose that the properties of the constructed ground states can be used to design new types of photonics applications.
scholarly publishing has many problems, a lot of degrees of freedom, and various dimensions on which one could measure success.   scholars have long been dissatisfied with aspects of the peer review system, but now there is an increasing sense that something drastic should and could be done about it. in the present article   we discuss some recent reform proposals given our own experiences publishing in theoretical and applied statistics.
we study the entanglement of a pair of accelerating quark and antiquark in the context of the ads / cft correspondence.   we consider the four - gluon scattering, whose minimal surface was well studied by alday and maldacena @xcite. using all such data, we write down the causal structure of the scattering process in its t - dual space - time picture and conclude that einstein - podolsky - rosen ( epr ) = er is also supported in this case. to quantify the degree of entanglements, we calculate the world - sheet induced metric on the surface obtained from the minimal surface of the wilson loop of the trajectories of the particles and find the entropy of the final state created by the interaction between the two particles.
the geometric phase of a two - level atom interacting with a non - markovian environment is studied.   three kinds of methods which describe the non - markedovian process, projection superoperator technique, memory kernel master equation and post -Markovian master equation, are considered. in this paper   we calculate the geometric phase for the system governed by these equations and discuss the results obtained with different dissipation rates and different memory effects.
sabermetrics is a long tradition in predicting the outcome of athletic events.   it began in baseball, and was glorified in _   @xcite, but it has now extended to almost all major sports. with the growing popularity of sports gambling and " fantasy" sites, there is more demand than ever for statistical information about which players will succeed and which teams will win. here   we use a simple, weighted, and penalized regression model to predict the outcomes of major league baseball, basketball, nba, nfl, and nhl games using data going back more than thirty years scraped from the following websites : http://www.boston.edu/sports/soccer/ statistics/ sabermetrics/ prediction_analysis.html, http://baseball.wikihow.com/software/sabermatrics/index.php, and http://prospect.cs.umichicago.edu/. we compare our predictions to a theoretically near - optimal indicator and show that our model performs better than the one described in the literature.
the evolutionary behavior of stars with a metallicity value of @xmath3, a suitable lower limit for the amount of heavy elements in dwarf spheroidal systems, is investigated.   the results show that the evolution of red giant ( rg ) stars with masses around@xmath8 change in a remarkable way in a range of only few tenths of solar mass, an occurrence already known as  ( rgt ). according to the results presented in this paper, the onset of the helium flash has been taken at the model where the contribution of the star luminosity at the tip of the rg is assumed to be proportional to the contributions of the he core at the he ignition and the star brightness at the start of the emission phase.
heat conductivity of 1d lattices is well known classical problem related to microscopic foundation of fourier law.   the paper is devoted to the detailed simulation of the discrete lattices with on - site nonlinearity and quadratic potential of nearest - neighbor interaction and investigation of their heat conductivity. for every case the dependence of the heat conductivities on the temperature and parameters of the lattice will be explored and concrete elementary excitation responsible for the change of regimes will be revealed.
the potts model is one of the classical models of statistical mechanics exhibiting a phase transition. in its standard version  , it is defined on the square lattice @xmath1, where it was first studied using random cluster methods.   the parameter controlling its phase transition is temperature : at sufficiently high temperatures the gibbs measure is unique, while for low temperatures the number of translation invariant extremal gibbs measures ( pure phases ) coincides with the cardinality of the spin state space ( usually denoted by @x Math0 ). when@xmath0 is large enough, these regimes meet at a specific value of the temperature where @x math0 distinct " ordered " phases and one " disordered " phase coexist.. this was shown in @xcite by using reflection positivity arguments, and in @xaite by pirogov - sinai theory.    the difficulty lies in the fact that there are no obvious extensions to the continuum of the methods available for the lattice Potts model. here   we investigate the structure of clusters in terms of their dissociation probabilities under resampling of locations, and show that clusters with positive dissociation probability are unlikely to occur uniformly in
the behavior of hadronic cross sections at high energy has been the subject of intense theoretical and experimental investigations for several decades.   these studies will become even more relevant with the advent of the low - energy collision ( lhc ), where protons will collide at a center - of - mass energy of 14  tev. in this paper  , we will focus on the forward elastic amplitude @xmath0 for the scattering of two hadronic objects at total rapidity @x Math1, one of the objects ( called the probe ) being characterized by a tunable momentum @x math2, that defines the scales in the plane transverse to the collision axis.. the other hadron will be called the target.    the scattering occurs at a given impact parameter that, here, will be fixed. 	 experimentally, the corresponding process could be, for example, deep - inelastic electron - proton scattering, in which the exchange of photons would be of order of the virtuality of the exchanged photon.
relativistic hydrodynamics of the perfect fluid may be considered as the standard framework for the description of the intermediate stages of relativistic heavy - ion collisions @xcite.   however, despite the clear successes in reproducing the particle transverse - momentum spectra and the elliptic flow coefficient @xmath1, the typical approach based on the relativists can not reproduce correctly the pion correlation functions. in particular, the ratio of the so called hbt radii @x Math2 and @xMath3 comes out too large, exceeding the experimentally measured value by about 20 - 50%. here   we present our results describing the intermediate steps of the interaction between pions and kaons using the recently developed 2 + 1 boost - invariant inviscid hydrodynamic model linked to the statistical - hadronization model therminator@xcite which takes into account the initial eccentricity fluctuations obtained from the monte - carlo glauber model.
the time projection chamber ( tpc ) with a micro - pattern - gas - detector ( mpgd ) for the ilc @xcite is presented.   the setup consists of a 5gev electron beam fieldcage with a 26 cm drift length and a field cage with a diameter of 26 cm, which is used to study cluster and track properties for longer drift distances.    the timepix cmos readout pixel chip is used as a highly segmented charge collecting anode. in order to record simultaneously time and time - over - threshold information the time pix is operated in a special mode : in a checkerboard - like fashion consecutive pixels are set to tot and time mode.. consequently half of the pixels record time, while the other half records tot. 	 the readout is performed using a similar scheme as in the university of freiburg setup. at the bonn setup   two scintillator counters are used as trigger for cosmics measurements. here   we present the results of tests with the triple gem / timepx setup developed by the lctpc collaboration at desy.
ultracold atomic gases in optical lattices may be used as analog quantum simulators of condensed matter models.   simulating the fermi - hubbard model is particularly interesting because it is nearly impossible to solve using traditional techniques, yet is amenable to simulation with cold atoms. here   we explore how light scattering can be used to detect magnetic order in a gas of fermionic atoms in an optical lattice, focussing on the antiferromagnetic order found at low temperatures in the insulating phase of theHubbard model. producing ( and detecting ) such an anti - magnetic state is a key step on the road to exploring superfluidity in the hubbard Model.
we present a new eulerian hydrodynamical code for the formation of zeldovich pancakes.   we introduce three temperatures to describe the thermodynamic evolution of electrons, ions and neutral particles in the early stages of the pancake collapse process. using this code, we model the chemical evolution of the primordial hydrogen - helium gas without assuming ionization - recombination equilibrium and also model electronic conduction with a flux - limited diffusion scheme. as a result  , we show that the equations governing the system are well suited for non - equilibrium processes such as thermal waves escaping out of the shocked region together with an equipartition wave where electrons and ions temperatures can differ significantly.
the zone of avoidance ( zoa ) is a large area of the optical and infrared extragalactic sky that is highly obscured by dust and high stellar density.   we have conducted a blind high - resolution ( hi ) survey of the zoa using the 21-cm multibeam receiver ( mbe ) telescope at the arecibo observatory in belgium to search for gas - rich galaxies in the region of @xmath13.0  mag, which is the most opaque part of the galactic plane. from the results of this survey, we have identified several highly obscured galaxies, including the ic  342/maffei group, circinus, and dwingeloo 1, which are located in the northern zoa. while the majority of these galaxies are likely to be near the center of the local group, some may be further out into the galaxy plane as far as ~3.5  km  s@xmath5. here  , we review the current state of the art in the study of the Milky Way's zoa and discuss the limitations of the present survey.
the optical transient of gamma - ray burst ( grb ) 990123 was monitored for 3 nights during january 1999 from 23 to 25 using 104-cm sampurnanand telescope located at upso, nainital.   the observations were carried out under a long term collaborative programme between danish, german, indian, italian, mexican and spanish astronomers coordinated by one of us ( ajct ). in order to improve the s / n ratio of the optical transient, the data have been binned in @xmath11 pixel@xmath12 and also two or more images of a filter have been stacked after correcting them for bias, non - uniformity in the pixels and cosmic ray events. on the night of 23/24 january1999, the observed optical transient was as faint as @x Math13 mag with an accuracy of 0.10 mag using a telescope of aperture 1 m. the decay light curves are presented in @Xmath6 photometric passbands by combining them with the data published in gcn observational reports.
the detection of boson stars, either as compact objects or as bricks of the dark matter component, necessitates studying their behavior under general nonspherical perturbations.   extracting their particular gravitational wave signatures requires a fully general relativistic 3d code. in this paper   we study the nonradial quasinormal mode frequencies of spherical boson star systems and the gravitational wave signals generated by such systems. using the fully general 3d simulation code presented in @xcite, we find that the zerilli and the newman - penrose gravitational waveforms are fully consistent with the predictions of yoshida and kesden for the spherically symmetric configuration of a bosonStar system. to investigate the properties of the complex scalar field, we perform a series of long - term stable 3d simulations of these systems with general symmetry and construct a full gravitational wave signal from the results of the numerical investigation of the head - on collision of two cosmological particles.. the results show that the gravity of the system is sufficiently strong to generate gravitational waves at the center of the particle.
we present the results of deep optical narrow - band imaging of ngc  6240 using the subaru suprime - cam.   we show that the central h@xmath0 nebula ( " butterfly nebula " ) is spatially coincident with the soft x - ray - emitting hot gas surrounding the double nuclei of the colliding active galactic nuclei ( agns ) of the progenitor galaxies @xcite in the 0.210 kev band and the extended ionized gas region surrounding this galaxy ( ~80 kpc in diameter ), which is thought to be excited by shock - heating induced by a starburst superwind.    our observations are the first to reveal the detailed structure of the extended h@Xmath0 emitting warm ionized gases surrounding ngc 6240.
the atmospheric neutrino flux is a fundamental input to the analysis of the data collected by underground neutrinos in the earth geomagnetic field.   the present work reports the results of a new approach to the calculation of this flux using an event generator describing the cosmic ray ( cr ) induced cascade in the atmosphere, particle propagation in the geom magnetic field, and interactions with the medium. for the first time, the absolute values of both the primary cr flux and the atmospheric secondary flux have been calculated within the range of ~20 to 25% of the experimental values reported in previous works, which are based on the calculations of the production cross section of the parent particle ( @xmath0 ) from the collisions of crs with atmospheric nuclei over the relevant energy range@xmath1. the results show that the obtained values are well within the acceptable limits of the experimentally observed east - west ( ew ) asymmetry of the neutrine induced events, which is expected to originate from the ew asymmetry between the measured and calculated fluxes.
quantum effects are of vital importance on collective phenomena in dense plasmas, which may be encountered in astrophysical objects like white dwarfs, active galactic nuclei and neutron stars @xcite or in metals and artificially manufactured compounds like semiconductors and nano - structured materials.   quantum hydrodynamics ( qhd ) model is applied to investigate the higher - nonlinearity effects on electron - acoustic solitary excitations in two - electron - type quantum electron - ion plasma with degenerate and non - degenerate electrons and additional neutralizing background inertial ions. by using reductive perturbation method,   the korteweg de vries evolution equation is obtained and the stationary solution to higher - order soliton amplitude approximation is obtained.    the results obtained here are discussed based on the numerical analysis.
the holographic dark energy ( hde ) model based on the infrared ( ir ) cutoff of the holographic principle @xcite has been proved to be a competitive and promising dark energy candidate.   the parameter @xmath1 plays an essential role in characterizing the dark energy properties in the hde model, e.g., with the value of @x Math1 being bigger or smaller than 1, the behavior of hde in the far future would be phantom - like or quintessence - like, which means giving very different ultimate fates for the universe. in this paper, we generalize the original hde models by treating the parameter@x math1 as a free function of redshift, i.e., @xMath2.    we study the observational constraints for these ghde models, by fitting the cosmological parameters to the experimentally observed data, and find that the results are in good agreement with the experimental results.
we have developed a new integrated code for the calculation of radio emission from cosmic ray air showers using the geosynchrotron approach based on the endpoint formalism @xcite.   the code is named coreas and is available in version 1.0 ( available at http://www.corsika.org/products/coreas/ ). it provides the position, time and energy of each tracked particle at the start- and endpoint of individual track segments in corsika and then uses these to calculate the radio emission with the end - point formalism. as the performance of the code   is much better than that of reas3, we can do calculations on very fine grids and thus produce some particularly instructive plots.
we study the identification of the schmidt number ( sn ) of a quantum state by witnesses in terms of arbitrary hermitian operators and optimized, necessary and sufficient conditions for the detection of entanglement.   we provide a method that delivers so - called separability eigenvalue equations for all optimized sn witnesses.the optimization yields equations which resemble the well - known eigen Value problem, but they include the factorization property of pure local quantum states. with some fundamental examples, we generate some general classes of sn witnesses and apply them to mixed quantum states.the results are compared with the well known spectral decomposition and the sch Schmidt decomposition of quantum states ; properties of the solutions of these equations are also studied.
in this paper, we study the problem of minimizing the users symbol error rates ( sers ) directly in the @xmath0-user single - input single - output interference channel ( ic ) by applying improper signaling over finite signal constellations.   we find that improper gaussian signaling can provide rate gains for ics over the conventional gaussian signals ( pgs ) under the finite signal - to - noise ratio ( snr ) regime. with the aid of interference alignment ( ia ),   the maximum achievable rates in terms of degree of freedom ( dof ) have been obtained for the four - user siso ic with proper pgs and improper pgs.
hybrid automatic - repeat - request ( arq ) has been proposed as an enabling method for satisfying quality - of - service ( qos ) constraints in wireless systems.   hybrid - arq methods are particularly useful in mesh networks, where relays that are closer to the destination than the source can forward additional parity information to a distant destination if the destination detects uncorrectable packet errors. in this paper  , we propose a decentralized relay selection approach that relies on random access - based feedback to the source. in our approach,   the source uses " hello " messages from the relays to select a relay to forward parity information at the destination if it detects an uncorrected packet error.    the " hello" message feedback is controlled by factors including the relay channel gain to the target node. here, we present and discuss the effects on system performance of varying key parameters such as the feedback probability and channel threshold.. our approach significantly outperforms a point - to - point hybrid - Arq strategy where the source forwards the parity information into the destination. also, our strategy yields throughputs that are very close to those yielded by the gps - based strategy in @xcite.
the vhe @xmath0 ray experiments have been used to find the cut - off energies for the emission mechanism acting at the mev - gev energy region in the environs of the pulsars.   while the recent trend in the field has been to lower the threshold energies, it is interesting that one has really to look at the higher energy part of the data to detect this emission. here   we will review the results of the vhe@x Math0 ray experiment which has started out at pachmarhi in india and will be specially looked at for evidence for these higher energy emissions.
we use high resolution cosmological simulations to quantify the contribution from non - thermal pressure support against gravity in relaxed clusters of massive galaxies.   we derive the hydrostatic and thermal gas pressure profiles for massive relaxed clusters drawn from adaptive mesh refinement simulations of the intra - cluster gas ( icg ) using the equation of hydrostatic equilibrium, assuming spherical symmetry and strict hydrostatic equilibration. as an example  , we test the validity of the common assumption of strict hydro static equilibrium in abell 1689, one of the most thoroughly investigated massive galaxy clusters with a total mass of @xmath2@xmath3, located at a redshift of 0.183. under this assumption, we find that the mass derived from x - ray observations in the central region of a1689 is significantly lower than that inferred from gravitational lensing measurements.  also, we show that even after equilibrium is established, subsonic random gas motion in clusters contributes a significant fraction of the pressure supporting against gravity.
a novel technique is developed to analyze a class of non - gaussian input distributions over gaussian noise channels.   this technique is efficient to analyze the competitive situations occurring in the network problems described below, i.e., a degraded gaussian broadcast channel with coherent memoryless fading, a two user interference channel, and a gaussian intersymbol interference channel. for each of these problems,   the optimal input distributions are found to be gaussian when the external noise is gaussian distributed. however, it has been an open problem to show whether gaussian inputs are optimal or not for a gaussian broadcast channel ( bc ) with a coherent fading known at the receiver, even if the fading is such that it is a degraded bc. here  , we show that there are certain non -gaussian ensembles that outperform gaussian ones on all three cases of the above problems. using the new technique, we find that the best output distributions for the gaussian bc with coherent fading are those that maximize the mutual information of the two users but minimize the performance of the first user under an average power constraint given by @xmath1, whereas the best outputs for the other users are
we present a theoretical model of spin - polarized cotunneling through a single - level quantum dot coupled to ferromagnetic leads with non - collinearly aligned magnetic moments.   the external magnetic field required to control magnetic configuration of the system is assumed to be small enough to neglect the zeeman splitting of the dot level. in the case of symmetric anderson model, where the system parameters are equilibrated, the zero - bias anomaly in differential conductance decreases monotonically with increasing deviation of magnetic configuration from the antiparallel alignment, and eventually vanishes in the parallel configuration. on the other hand, for the system described by an asymmetric andersen model, which is in the coulomb blockade regime, the anomalous behavior of the differentialconductance leads to a related anomaly in tunnel magnetoresistance ( tmr ), which for arbitrarily aligned magnetizations of the leads can be defined as @xmath5/i(\varphi)$, where@xmath6 is the current flowing through the system in the paralleled configuration and@x Math7 is thecurrent flowing in the non - concave configuration.we show that the angular dependence of tmr strongly depends on
radiative recombination ( rr ) of bare, high@xmath0 ions is a basic process that occurs in many stellar and laboratory plasmas as well as in collisions of heavy ions with electrons at ion storage rings and electron beam ion traps.   the electron capture into the excited ionic states which later decay under the emission of one ( or several ) characteristic photons @xcite is characterized by its angular distribution and polarization of the emitted photons. in this contribution  , we study here the polarization correlations between the recombination and the subsequent decay photons in the @xmath5 radiative recombinations of bare,high@x math0 ions. for the first, recombination photon, the polarization state of the emitting photon is assumed to be unobserved, while the spin states of the corresponding decay photons are also unobserved. using the density matrix theory, we derive the general expression for the double  differential rr cross section which depends on the emission angles and the polarization states of both photons. starting from this cross section,   we perform a theoretical analysis for two selected scenarios of possible x  x coincidence studies : 1 ) the _ angle  polarization   correlation in which the linear polarization of
we present the unexpected detection of a he  ii  @xmath04686    variable emission line in the spectrum of the luminous blue variable @x Math1 carinae.   the line shows up in almost all of our high quality spectra, except in a few ones of lower s / n. paradoxically, this line is faint in high excitation phases and strong during the event, contrarily to the behavior of the high excitations forbidden lines. by fitting the line to the stellar continuum, we show that it is a very low frequency emission line, with an upper limit of 1.5  s/n, which is much lower than the upper limit reported by hillier and allen ( 1992 ). at the same time, the line is strongly correlated with the radial velocities of the line centroid, suggesting a binary nature of the star.
summaryagn outflows are evident by resonance line absorption troughs, which are blueshifted with respect to the systemic redshift of their emission counterparts.   reliable measurement of the absorption column densities in the troughs is crucial for determining the ionization equilibrium and abundances of the outflows, and the relationship between the uv and the ionized x - ray absorbers. here   we use a pure partial covering model to determine the optical depth of two troughs arising from the doublet lines of a given ion ( e.g., ngc  3783 and mrk  279 ). using the apparent optical depth method, we find that the actual optical depth is much lower than previously assumed. as a consequence  , the column density can be inferred only from the depths of the troughes. instead, we show that the absorption columns of the absorbed troughs are almost entirely due to changes in the line of sight covering as a function of velocity, rather than to differences in optical depth.
measuring the casimir force in the plane - sphere geometry at finite temperature has been the aim of an increasing number of experiments in the last years.   the comparison of these measurements with predictions from quantum electrodynamics theory has been applied to put constraints on hypothetical new forces predicted by unification models @xcite. in this paper  , we develop the beyond - pfa scattering approach for the above - mentioned geometries, with material properties described by either the perfect reflector, plasma or drude models.we show that the interplay between temperature and material properties is drastically affected when the parallel - plate configuration is replaced by the plane-sphere geometry. as a consequence, the results obtained from the drude and plasma models are generally closer to each other than in the parallelplate geometry. in particular, the factor of 2 between the two models reached at the limit of long distances between parallel plates is reduced to 3/2 for a plate and a sphere, and even less if small spheres are considered. finally, we find that the proximity force approximation ( pfa ) underestimates the thermal contribution to the cas Vladimir force for the dissipative drude model at short distances, whereas it overestimates it at all
the casimir force between two uniaxial birefringent plates is studied in a setup where the non - magnetic mirror is optically isotropic and the ferromagnetic mirror is made of a uniaXially bireFringent material.   the casimir effect is considered, and the influence of the magneto - optical kerr effect on the cas Vladimir force is studied.    interestingly, we find that the Casimir force gives rise to a magnetic anisotropy in the ferroma.. the magnetic aniostropy is more prominent in the iron layer than in the glass layer, and is due to the presence of a non - negligible magnetic response on top of the electric one.
we analyze new x - ray timing and spectral data on 4u  0614 + 09 ( preliminary reported previously in van der klis et al.    ), a low - mass neutron star binary in sco  x1, which has been observed in the x -ray burster and suspected atoll sources. we observe twin khz quasi - periodic oscillations ( khz qpos ) that move between 480 and 800  hz, and 520 and 1150  hZ, respectively. for the first time   we present an analysis of the photon energy spectrum of the oscillating flux in these waves.
we propose a new method to reconstruct the x - ray scattering halos associated with point sources from the continuous clocking ( cc ) mode data and/or the transmission grating data of the advanced ccd imaging spectrometer ( acis ) aboard the chandra X - ray observatory.   the method is based on subtracting the point source surface brightness predicted by the point Source flux and the point spread function ( psf ) of the instrument from the observed surface brightness, then comparing the inferred fractional halo intensity ( fhi ) as a function of the off - axis angle to those predicted by different halo models in order to deduce the halo properties. after testing it with the marx simulation  , we applied this method to cygnus x-1 observed with the ch Sandra high - resolution x -ray observatory using the timed exposure ( te ) mode of the acis, which is the mode with two - dimensional ( 2-d ) image, and to the data of gx339 - 4 with ipc / einstein in the broad energy band of 1@xmath0 for the interstellar medium ( ism ) and gx17 + 2 with rosat.
the first - order irreversible phase transition ( ipt ) characteristic of a model for the @xmath1 reaction early proposed by yaldran and khan ( yk ) @xcite is studied by means of monte carlo simulations with particular emphasis on the occurrence of hysteretic effects.   the results are compared with those of our previous study of the ziff, gulari and barshad ( zgb ) model@xcite.
we present a new mesoscopic approach to model self - organization processes of nanometer - sized vacancy / adsorbate islands lattice on metal surfaces.   the method is based on modified phase field crystals method ( modified phase fields method ), where in the framework of continuous model one can describe processes at microscopic and diffusion scales. for system of systems with adsorption - desorption and diffusion processes the typical deterministic equation, which will interest us is of the form @xmath3 where @x Math4 is the local coverage at surface defined as the quotient between the number of adsorbed molecules / atoms in a cell and the area of the cell covered by adsorbated cells.. the main advantage of this approach is in introduction of a crystalline order with elastic interactions leading to formation of crystal lattice and of inertia effects related to a finite propagation speed. here   we show that the influence of internal and external stochastic sources on pattern - forming transitions in such kind of systems is well described by taking into account the swift - hohenberg operator.    the results are compared with those of previously reported methods.
we perform a detailed analysis of the effect of the long - range character of the interaction between charges on the transport properties through ordered and disordered one - dimensional arrays.   we consider the influence of charging and resistance disorder on the interactions described by an inverse capacitance matrix, in which coupling to other conductors is not truncated. for the cases with and without charge or junction resistance disorder, we analyze the threshold voltage, flow of current and voltage drop through the array including the effects of screening and polarization potential drop at the junctions between the nanoparticles. using a model to describe the electrostatic interactions among the charges occupying the islands and the electrodes, we show that the distance - dependence of the coulomb interaction depends on the size of the tunneling barrier and the length of the nanometer range of the nanoparticle. as a result  , there is a strong correlation between the concentration of the charge in the electrode and the distance from the electrode to the island ( r2 = 0.99 ).    in the case of the array with charge disorder, the separation of the islands is more sensitive to the number of charges in the substrate than in the array without charge disorder. when the diameter of the
protoplanetary disks are a product of the formation of protostars from the collapse of molecular cloud cores and are the birthplaces of planetary systems.   the evolution of the disk and of its planetary progeny is controlled by heating and irradiation from the central star  from ir to x - rays  but in the vicinity of ob stars can also be significantly affected by the external radiation environment. while the observational database of protoplanetary disks continues to grow, all attempts at theoretically modeling the emission expected from such environments have lacked several of the ingredients needed for a fully self - consistent approach. here   we present a new chemical model of the gaseous component of the inner regions of non - evolving t  tauri disks ( @xmath9  myr ) where both terrestrial and giant planets are believed to form. using a combination of experimental and theoretical data from the alma space telescope, we show that the observed density and temperature structures of the gas component of these disks are well within the range of the expected emission lines, while the ionisation fractions at the disk midplane are very close to the limit of agreement with those predicted by previous work on the theory of the hydrodynamical evolution of
laser - driven proton and ion acceleration is a promising field of research.   the accelerating fields sustained during laser - matter interactions at relativistic intensities are orders of magnitude higher than those used in conventional accelerators, reaching up to tv / m2 in strengths. here  , we investigate the effect of an external magnetic field applied along the laser propagation and normal to the irradiated target in proton acceleration experiments using two - dimensional ( 2d ) particle - in - cell ( pic ) simulations with the goal to determine how an externally applied magnetic field impacts proton energy gain and the divergence of the proton beam.. we find that a kt - level external magneticfield can sufficiently inhibit transverse transport of hot electrons in a flat laser - irradiated targets to enhance the maximum proton energies and the overall number of energetic protons. while the electron heating by the laser remains mostly unaffected, the reduced electron transport during proton Acceleration leads to an enhancement of the maximum Proton Energy and the total number of accelerated protons compared to a beam generated without applying a kT - level magnetic field. for proton accelerator experiments,   this effect is even more important because the proion
the generalized local - density approximation ( glda ) is a new local two - electron parameter in density - functional theory ( dft ) that measures the tightness of the correlation hole around an electron.   it is based on electrons on an infinitely thin wire with periodic boundary conditions ( pbc ), and corresponds to electrons on a ring interacting  through  the ring @xcite. here  , we investigate the performance of the glda for one - dimensional ( 1d ) systems using a non - self - consistent post - hf procedure. by combining quantum monte carlo calculations and exact results from the high - density and low - density limits of the infinite uniform electron gas ( iueg ) model@xcite, we show that the experimental results are in good agreement with the calculated glda correlation energy.
a generalization of the problem to multiple datasets, termed, has been introduced recently @xcite.   the recent interest in is motivated by various application domains such as when analyzing multisubject datasets in biomedical studies using or data@xcite or when solving the convolutive problem in the frequency domain using multiple frequency bins @xcite. in this paper,   a general framework for identifying sources that can not be identified by, @Xcite is presented. prior to introducing this formulation in section iv  , we give a review of existing algorithms and define our mathematical conventions and notations in section iii.the identification conditions and source separation performance bounds are generalizations of the results for ( of a single dataset ) which can be derived from two different, but related principles ; maximum likelihood and eigenanalysis ( diagonalization ). here, we choose to separate the approaches into three classes for our review based on the source diversity exploited to achieve. each type of diversity can be utilized independent of the other two  . the first class is applicable to problems in which the sources are assumed to have linear dependence across datasets, but are linearly independent within datasets. since can be achieved using generalized eigenvalue
the area law of the fractional quantum hall ( fqh ) ground state in arbitrary polygonal domains is calculated for the landau model for a particle in a cylinder of size @xmath14.   the entanglement entropy is given by the area law plus a contribution due to the vertices, @x Math5, that only depends on the angle of the vertice and the density of the fluid of electrons. for higher filling fractions and different geometries, the calculation of @x math5 is more generalizable than for the iqhe state with filling fraction defined on a cylindrical geometry.
turbulence is a generic phenomenon observed in the relaxation dynamics of many - body systems far from thermal equilibrium.   it comprises a quasi - stationary flow of energy within certain inertial regimes in momentum space, and its scaling is a nonthermal fixed point of the system s dynamics. in this article   we present the details of our studies of the relaxation of two and three dimensional dilute bose gases through stages of superfluid turbulence and the approach of a nonThermal fixed points by means of simulations in the classical - wave limit of the underlying quantum field theory. while we find excellent agreement with the numerically determined scaling laws for the single - particle momentum distribution in the ultraviolet ( uv ) quantum boltzmann kinetic regime, we also find that the scaling exponents of the velocity distribution are significantly larger in the infrared ( ir ) regime than in the uv regime. as a consequence, we propose strong matter - wave turbulence in the regime of long - range excitations.
gx 339 - 4 is an unusual x - ray binary with a compact absorbed core and a hard tail.   the source was detected by simultaneous observations of the australia telescope compact array ( atca ) with the molonglo observatory synthesis telescope ( most ) at 6.3 & 3.5 cm for the first three nights, and at 21.7 & 12.7 cm on the fourth night. over the past @xmath4 months   we have monitored the source with the atca in a high - resolution 6 km configuration at 36 cm from the source using the molonga telescope. during these observations   there were clear night - to - night variations in the flux density and spectral index of the source's radio emission, consistent with quiescence or quiescent state. while the source has a roughly flat radio spectrum, similar to that of cyg x-3 in quyingcence, the source also has a relatively flat spectrum in all four wavelengths, indicative of a compact absorption core. as the source moves closer to the center of the binary it will be more likely to quiesce than previously thought, and this will be confirmed by the extension of the observation range to
asteroseismology is a powerful method for determining fundamental properties of stars.   we report the first measurements of solar - like oscillations in a metal - poor star, the subgiant ( hr  8515 ; hd 211998 ; hip 110618 ), whose iron abundance is only 3% of solar. using the ucles and coralie spectrographs, we have measured the oscillation velocities of this star over a period of about 50min from two different sites. with ucles we obtained 680 spectra of, with typical exposure times of 300s ( but sometimes as short as 200s in the best conditions ) and a dead time between exposures of 61s. with coralie we obtained 521 spectra, with typically exposure times that range from 360s to 360s. during the overlap between these observations,   the star oscillates at frequencies of 0.61mhz and 0.9mhz, with an average amplitude of about 1.5 j / cm2 per night. by combining the data from both instruments, we calculate the average noise per minute of observing time to be 17.3 for ucles, 27.2 for coralie and 14.9
the critical velocity of a clean superconductor in one spatial dimension is re - analyzed via a mean - field treatment, and the dependence of this velocity on the temperature is obtained.   we find that at zero temperature the critical velocity is smaller by a factor of @xmath0 than the landau critical velocity ( @x Math1 ). even though for@xmath17 a gap in the quasiparticle excitation spectrum remains, the superconducting state first becomes unstable there.    this is in contrast to a previous report   @xcite, which held that the critical speed was @x maths1, i.e., the velocity at which the gap in its quasiphase spectrum closes and excitations proliferate so as to destroy superconductivity. here  , we show that the pre - emptive clogston - chandrasekhar  like discontinuous phase transition is the cause of the smaller critical velocity.
understanding physics at shorter distance scales always gave us better understanding of physics at a previously known longer distance scale.   the main motivation of supersymmetry is to stabilize the electroweak scale against radiative corrections, which tend to make it much shorter ( as short as the planck length ) or much longer ( no electroweak symmetry breaking ). once we accept this mechanism, we are allowed to speculate physics at much shorter distances, and ask questions about the origin of gauge forces, fermion masses, and even cosmological issues such as baryon asymmetry. in this short article  , we will present various possibilities how we may be able to probe physics at such short distance scales using supersymmetric as a probe. for each example of such probes in the following sections, we try to make explicit what the underlying assumptions are.
the dwarf ( dedicated worldwide active galactic nuclei research facility ) network is a global network of several small cherenkov telescopes that will be operated in a coordinated way for long - term monitoring observations of the brightest blazars.   this network will have to be distributed around the globe for 24/7 monitoring, preferably with temporal overlap and redundancy to account for weather and duty cycle constraints, as well as for muon background reduction.the prototype telescope of this network is the former hegra ct3 telescope, located at the roque de los muchachos on the canary island of la palma, mexico, which has been refurbished with an enlarged mirror area and a robotic design @xcite. since 2005, the whipple telescope located on mt. erythematosus in arizona, usa has been used for nightly monitoring observations and since 2007 it was decided that whipple observations will dovetail with those of the dwarf telescope @xfite. the tactic telescope situated on mt..   abu, india is also dedicated to long - time observing observations and it can be operated within the dwarf network @rfite. two of theFormer hegra air cherenovks telescopes
dynamical mean - field theory ( dmft ) is a powerful tool for understanding strongly correlated electron systems.   the purpose of this work is to develop a strong coupling approach for interacting lattice problems. within this approach,   we construct a systematic generalization of the dm ft technique capable of describing any non - local term of a generic lattice hamiltonian. in terms of hubbard operators, we can write the two contributions as @xmath4 and@xmath5 in terms with single - site states, and describe the perturbation theory for a general hamiltonians of the form    @x math0   containing a local term, @x Math1, and a non -local one, @Xmath2.    the formulation is based on an expansion around the atomic limit of infinite lattice coordination, and provides a consistent description of the coupling constants for each of the three main types of hamiltonias.. the results are compared with the results of the extended dmfts@xcite and the single site dmFT@xcites.
the nonlinear description of plasma oscillations is of interest as a result of its importance to the semiconductor industry.   it is also important in other sectors such as biomedecine, automobiles, defence, aerospace, optics, solar energy, telecommunications, textiles, papers, polymers and waste managment. in the present paper, we concentrate our studies on the model and equation of motion, the resonant states, the chaotic behavior. through these studies  , we found the effects of differents parameters in general and in particular on the effect of the hybride quadratic parameter @xmath8 which shown the difference between this equation and anharmonic equation which obtained in @xcite.
in the present article i write my personal overview of five topics that have been centrally placed in the field of nuclear - structure physics in respective decades. those topics perhaps except for the most recently developed drip - line physics have been developed in the way either strictly followed from the ideas of bohr and mottelson or strongly influenced by their way of thinking physics, and the topics are those, the study of which i myself have also eagerly worked in. in sec.   ii particle - vibration coupling, in sec.   iii one - particle motion in deformed and rotating potentials, and yrast spectroscopy in high - spin physics, insec. 	 iv triaxial shape of nuclei, in Sec.    v nuclear structure as neutron - drip - lines approaches, and in sec!   vi nuclear shell - structure in oblate deformation are presented, while conclusions and discussions are given in sec!
the growing cpu - memory gap implies that the cost of main memory access is now the dominant cost in database operations.   we have developed a new algorithm for data retrieval, called dpg, which uses two - pass memory management ( dpg ) to avoid the use of random access to main memory. with the dpg record retrieval algorithm replacing the standard record retrieval algorithms, we immediately produce a faster sorting algorithm than alphasort and superscalarsort, the current record holders for the datamation sorting challenge on an ibm p690 turbo. using this algorithm, we also find that the time spent waiting for the latency of ram access is reduced by up to 50%. at the heart of this memory bottleneck   lies the problem of copying records from a source array into a destination array according to a new ordering.
Bell measurement is a crucial element of quantum communication and quantum computation protocols.   it discriminates between four entangled states known as bell states, where @xmath1 and @x Math2 are the logical qubit bases. in optical implementations,   single photons with their polarization degree of freedom are typically employed to construct logical qubits @xcite. for a single photon qubit  , the bell measurement can be implemented using linear optics and photodetectors @xaite, which we shall refer to as the standard bell - measurement scheme. due to this reason, the success probability of the standardBell measurement is limited to 50% @xcire, and it has been a fundamental hindrance to the implementation of a deterministic quantum teleportation and scalable quantum computation with linear optics @xcites. in this paper, we discuss a scheme for implementing a nearly deterministic bell measurement with linear optoelectronic elements and photon on - off measurements@xcite based on a greenberger - horne - zeilinger ( ghz ) type multiphoton entanglement. here   we show that the logical bell states can be efficiently discriminated by performing @x math3 times of standard bell measurements, where ~3
the problem of the restoration of the chiral symmetry of the strong interactions in the nuclear medium has been extensively addressed.   the interest has largely focused on the quark condensate, considered as the order parameter. for independent particles the evolution of the quarks with density or temperature is governed by the sigma commutator of the particles present in the system. at normal nuclear density   there is a large amount of restoration, which manifests itself either by a decrease of the hadron masses, or by a mixing between opposite parities. here   we give the explicit expressions of the axial and vector current in a formalism based on chiral lagrangians.we show that the nuclear pions renormalize the coupling constants of theaxial current and that the renormalization can be expressed in terms of the pion scalar density, which is the last quantity to be renormalized in the decay constant. this last quantity also enters in the quink condensates evolution.
we study the effect of environment on the dynamics of coupled systems in a complex network of complex networks.   we find that the coupling through the environment has a tendency to drive the systems to a state where the sum of the variables is small, which leads to the state of amplitude death. for this, we model the average effect of the environment by an over - damped oscillator which is kept alive with feedback from the subunits and find that it is effective in inducing amplitude death in two systems coupled by different types of coupling and of different intrinsic dynamics. using rssler as a standard system in its chaotic region, we show that the critical strength of coupling needed for amplitude death has a universal relation with the largest non - zero eigenvalue of the coupling matrix which is tested for many symmetric networks like chain, ring, tree, lattice, all - to - all, star, and random topologies.
interactions / mergers of galaxies are considered as important processes influencing morphological, stellar and chemical evolution of galaxies.   the aim of this study is to investigate the connections between interaction with a close neighbor and nuclear activity and/or enhanced star formation rates ( sf ) in galaxy pairs using the sample of close neighbors of mrk galaxies from ( *????   nazaryan et al. : ( 2012 ) ). for this study, the subsample of 217 pairs of galaxies containing at least one mrK galaxy is selected. by using sdss color images, we classified the morphologies of these galaxies and their neighbors by using different levels of perturbations. for statistics, we also included sf of galaxies and nuclear emission - line classification ( bpt ) of their sdss spectra. according to the results of our study, it is concluded that the size of the interacting galaxy and its close neighbor can affect on the frequency and efficiency of enhanced sf and agn triggering by interactions and merging.
the broad fe k@xmath19 fluorescent emission line in active galactic nuclei ( agns ) provides an important tracer to probe the physical conditions and geometrical distribution of matter in the vicinity of supermassive black holes.   the line is believed from the accretion disk by reflecting the illuminating x - ray continuum, and the unique broad and skewed ( toward the red ) line profile is a consequence of the relativistic doppler effect and strong gravitational redshift. in this letter   we present new xmm - newton observation on iras 00521 - 7054  taken in 2006, in which we detect an ultra strong and broad  line.we also describe the data reduction and detailed spectral fitting to the continuum and the emission line.
the high - energy transient swift j164449.3 + 573451 ( hereafter sw j16 44 + 57 ) was detected by swift burst alert telescope ( bat ) on march 28, 2011.   it is a star being tidally disrupted by a supermassive black hole ( smbh ) in the center of the galaxy at redshift @xmath0. since the x - ray and gamma - ray luminosity of this event is 2 - 3 orders of magnitude larger than the eddington lumosity of a smbh, the emission is likely to be produced by a collimated outflow. in this paper   we present an approach to calculate the parameters of the jet blast wave at any instantaneous time directly by using the radiation spectrum at that time. for both conical and cylindrical jets, we find that the outflow gradually transits from a conical jet to a cylindular one at later times. as the jet propagates outward, the cross section of the blast wave increases from a narrow jet at the beginning to a wide one at the end of the first few days after the trigger with the radio synchrotron emission. here  , we discuss the possible mechanism for the
the gross - neveu model family of four - fermion interaction models with discrete flavors and lagrangian @xcite is a well - known example of a solvable model in quantum field theory.   the dirac sea has been proposed as a way to solve these models  classically ", neglecting the sea and including only the discrete valence level. in the present work   we reconsider this approach and derive a new method for solving the same models in closed analytical form using an effective action derived from the underlying field theory ( e.g., the effective mass and coupling constant ). by combining the methods developed by dashen, hasslacher and neveus ( dhn ) and shei ( shei et al., 2015 )  , we show that it is possible to solve the first - quantized, time - independent dirac equation for single particle orbits with label @xmath12 subject to self - consistency conditions for scalar and pseudoscalar mean fields without the sea in the case of the massless nambu  jona - lasinio ( njl@xmath9 ) model @xcites.
we investigate the core / shell ( cs ) structures of boron nitride ( bn ) and graphene formed by their commensurate 2d hexagonal lattice.   we report the variation of energy gap with respect to geometric parameters of the structures and link these results to quantum confinement phenomena. in particular, we focus on the shape of the cs structures, in particular whether they have round or rectangular shape, which causes crucial effects in the electronic structure. using the spin - polarized density functional theory ( dft )  , we reveal the nature of the band edge states by analyzing the charge density profiles projected on those states. here   c / bn cs structure considered here constitutes a planar quantum dot.the effect of charging on these 2d quantum dots is investigated and the role of coulomb blockade is discussed in detail.
we study a naked singularity of a particular type  @xcite, which has been dubbed the _ repulson_ singularity.   we find that the constituent branes effectively repel one another ( in spite of supersymmetry ), forming in the end a nonsingular shell. as the name might suggest, this shell is composed of bent ns5-branes, wrapped / fractional d - branes, and non - bent d - Branes. by using yang   mills theory with eight supersymmetries, we find a striking parallel between the physical picture deduced in section  2 and the moduli space of the large-@xmath0 seiberg  witten theory, and the fate that we have deduced for the Repulson singularity.we also find some clues which allow us to guess at aspects of a possible dual.
the long - standing paradox about the electromagnetic radiation emitted by a uniformly accelerated charge has received considerable attention.   the relevant questions we consider are : does a uniformly accelerating charge actually radiate? in a constant gravitational field should free - falling observers detect any radiation emitted from a free - Falling charge? is the equivalence principle valid for such situations?   we take the converse approach and show that the electromagnetic field generated by a uniformly accelerated charge is observed by a comoving observer as a purely electrostatic field. to explain this puzzle, we need to recognize that the concept of radiation has no absolute meaning, and that it depends both on the radiation field and the state of motion of the observer.
dwarf galaxies are thought to dominate the cosmic scenery in terms of number density and therefore form an important morphological class of galaxies.   several investigators have studied the mass distributions of these galaxies and found that they are dark matter - dominated at nearly all radii. here   we study the dynamics of the outer disk of ngc  2915, a nearby blue compact dwarf galaxy with a late - type spiral. using deep h@xmath13 imaging of the stellar disk, we find that the observed rate of star formation is slower than predicted by theoretical models of the dark matter ( dm ) properties of this galaxy. for the central region of the galaxy,   the slow pattern speed of the star - formation is explained by a common, slow pattern directionality of @xmath19, which is consistent with the model proposed by @xcite. for both the central and the outer regions, however, the fast pattern speed is not associated with the observed radial distribution of the stars.
the ultimate limit for magnetization switching by magnetic field pulses may approach the picosecond mark  @xcite.   this is because the exchange interaction and the magnetic anisotropy become time - dependent in the femtosecond range, where the electronic degrees of freedom evolve in time in a non - adiabatic way ( the local magnetic moment changes in time ). to interpret the results in a simple and transparent way, it is desirable to be able to map the electronic simulations onto classical atomic models based on the heisenberg hamiltonian. in the present paper   we discuss how the evolution in time of the spin - density in time - independent static density functional theory ( tddft ) simulations can be used to extract an effective spin - dynamics, which in turns can be mapped on an heisenberger model. as a byproduct of such analysis   one can extract exchange parameters whose values are quantitatively rather close to those calculated with the broken symmetry approach.
the rashba effect @xcite in solids derives from the motion of an electron in a strong electric field.   the rashba spin - orbit coupling ( soc ) energy is well known to be particularly strong at metallic surfaces, but the impact of rashba soc on the surface states of mott insulators has come under more careful scrutiny recently because of possible connections to topological insulators@xcite. here   we show that synthetic soc can be used to dress atoms with a spin - dependent momentum and that these dressed states can be tunable to extremes not possible in solid states. using synthetic soc in optical lattices, we find that the raman beam - induced super - exchange coupling between sites leads to rich spin structures within the mott state @xmathite, which is driven entirely by rashba social effects.
the tacnode process is a critical process in non - intersecting brownian motion and random walk paths which appears when two groups of trajectories are asymptotically supported in two ellipses in the time - space plane such that they touch each other creating a tacnode ( self - touching point ) of the macroscopic boundary.   the aim of this paper is to give an explicit airy type formula for the multi - time correlation kernel of the hard edge tac node process, under the assumption that the parameters @xmath4 of the bessel process are non - negative. using the solution of a riemann   hilbert problem, we show that the formulation of the tacnode kernel in @xcite is equivalent to the one given in theorem   which is the main result of the present paper.
@xcite quantum dimer models ( qdm ) have been one of the main paradigms in the field of quantum spin liquids.   these models, where the hilbert space is spanned by hard - core dimer coverings of the lattice, are expected to capture the phenomenology of quantum antiferromagnets where the wave function is dominated by short - range valence bond configurations. here  , we study the nature of the phase transition from a liquid to a solid in a @xmath0 gauge theory on the triangular lattice. using a semiclassical approach, we show that the transition is a condensation of @x Math0-vortices ( dubbed _ visons _ ) and that the excitation spectrum is gapped at the transition point. as a consequence,   the wave functions of the visons and the evolution of their spectrum are not local but are instead local excitations created by operators which are local ( in the dimer variables ).
the main task of an experiment in the low energy ( @xmath4 mev ) physics is to study the influence of structure of excited levels of a nucleus on the parameters measured in the experiment, for example of the process of cascade gamma decay.   after that, the extraction of dynamics of intranuclear interactions out of these experimental values and their theoretical interpretation with the development of theoretical models required in practice @xcite for the nuclear parameters used in this case is discussed.
recent observations of type ia supernova ( snia ) provide the main evidence that current universe is in an accelerating phase of expansion.   the acceleration must be driven by dark energy component @xcite. because the nature as well as mechanism of the cosmological origin of the dark energy components are unknown some alternative theories have been proposed to explain the phenomenon of the accelerated expansion of the universe. here   we present some model comparison methods to confront existing cosmology models having observations at hand and compare them with the ones which do not have observations.
adic systems represent all measure - preserving systems on nonatomic probability spaces and all minimal systems on the cantor set.   they provide a convenient combinatorial description of the construction of systems by the cutting and stacking method, present tail fields of stochastic processes as the fields of adic - invariant sets, facilitate the study of measure - preserve and topological orbit equivalence, and present important and interesting particular systems for detailed study. here   we show ( theorem  ) that for the pascal system every edge ordering allows essentially faithful coding by the first three edges.we also establish a necessary and sufficient condition for an adic system of a fairly general kind to be topologically conjugate to an odometer.
an experiment involving a couple of entangled particles emitted in opposite directions from a common source has been proposed by k.popper as a crucial test for the copenhagen interpretation of quantum mechanics.   subsequently, a criticism of popper s proposal by collett and loudon appeared  @xcite, claiming that the experiment can not represent a key test for this interpretation because the non - negligible indeterminacy about the state of the emitting source would make undetectable the effects which the copenhans interpretation predicts. in this paper   we will resort to two ( equivalent ) arguments showing clearly the fallacy of poter s idea. on the first hand  , we will show that the results of the experiment are consistent with the theorem on the impossibility of any form of superluminal signaling using the quantum correlations implied by the entanglement theory. on The second hand, we show that both the amplitude of the scatter at l and the width of the slit at r are expected to decrease together.
the idea that entanglement may be used as a resource is central to the theory of quantum communication and cryptography.   however, there are, on the other hand, settings of interest where the properties of entanglements as resources are very poorly understood. in quantum communication complexity, for example, it is not known if prior shared entangler ever gives an asymptotic reduction in the number of qubits of communication required to solve general communication problems. in the multi - prover interactive proof system model, which has been studied in several recent papers,   the effect of prior Shared Entanglement on the expressive power of the provers in the interaction is much more complex. in this paper  , we review the current state of knowledge about the effects of prior Shareable entangulation on the expression of the bell inequalities, and discuss some of the open problems concerning them.
quantum discord is an information - theoretic measure of non - classical correlations, which goes beyond entanglement.   it is known to be sensitive to the choice of distance measures, since it may increase under local operations on the unmeasured subsystem. in this work,   we show that the geometric discord as defined by the 1-norm is the only @xmath1-norm geometric discord invariant under the class of channels considered in ref.@xcite and that it is equivalent to the negativity of quantumness for arbitrary bell - diagonal two - qubit states. using the trace distance in place of the hilbert - schmidt norm, we analyze the monotonicity properties of the 1:1 geometric discord for arbitrary Bell - diagonal states, finding out a very simple expression that is identical to the negative potential of the minimum entangler potential.
we propose a new extension of general relativity ( gr ) to the einstein - hilbert action, where the metric and the affine connection are taken as independent variables in the action functional.   this takes into account the fact that the curvature of the scalar field @xmath1 is non - trivial in the lagrangian, and that the coupling between matter and geometry is not minimum ; indeed, it is shown that the energy - momentum tensor of matter is no longer covariantly conserved, that is, under conditions where the cosmological constant @xcite is increased from 0.5 to 1.0 at the newtonian point of resolution, while the gravitational potential is decreased from 2.2 to 0.4 at the newly - discovered newtonial point of reference. for the first time, we show that this result is consistent with the existence of a non - minimum coupling between geodetic behaviour and the metric, which is due to the presence of a strong - interacting particle ( wimp ) arising from the fast - rolling of a scalar surface term in the energy density @x Maths = x(xmath0 ), which acts as an effective scalar
the carrier recombination dynamics in semiconductor quantum dots ( qds ) is typically analyzed in terms of exponential decays with a characteristic time constant @xmath0.   this kind of decay has been adopted from experiments in atomic physics which are discussed using two - level schemes corresponding to the following scenario : an electron has been excited to a higher lying atom shell, from which it relaxes to a vacancy of a lower lying shell. here   we show that decays which are to a good approximation mono - exponential can occur, but only under very specific conditions such as fully resonant excitation or very strong qd confinement. under other circumstances   there is a pronounced enhancement of the recombination rate and the decay rate is not monotonically exponential. for example, at elevated temperatures the scattering of confined carriers with lattice phonons becomes strong, as manifested by a strong broadening of the optical transitions @xcite. during plasma cooling,   the electrons are trapped by the ions and relax by photon emission. under such conditions   they are captured by the confinement potential and relax towards the qd ground state.see research article http://www.biomedcentral.com/1471-7007/
the hadronic energy resolution of the calice analogue scintillator - steel hadronic calorimeter ( ahcal ) was studied using test beam data.   the data collected during 2007 test beam campaign at cern sps with positive and negative pion beams in the energy range from 10 to 80  gev were analyzed. for a single particle energy resolution for pions, the proposed solution is based on the calculation of the conversion factor from visible signal to deposited energy in the ecal for non - showering hadrons using simulated muons and the measured muon response from test beamdata sets. by applying the developed software compensation techniques to the experiment data,   it was found that the calculated conversion factor can be used to improve the hadronic energies of the ahcal.
we present a configuration interaction ( ci ) method for the calculation of the hamiltonian of a parabolic quantum dot in a magnetic field.   the optimization explicitly accounts for geometrical and dynamical symmetries of single - particle states, and for many - particle asymmetries associated with the center - of - mass motion and total spin. by doing so   we obtain a reduced basis size and improved accuracy, which results in a reliable computation of electron - electron interactions in the strongly correlated regime. to test the accuracy of the proposed method we compare our results with quantum monte carlo ( qmc ) and stochastic - variational method ( svm ) and with previous results describing the evolution of the electronic droplet with the magnetic field using the same basis.
recent measurements of o stars winds indicate that their mass loss rates, @xmath0, may be significantly less than previous estimates and expectations.   the primary mass loss diagnostic used in these analyses is p  v  @x Math1, but the ion fraction of p@xmath2 is a na - like ion, and can be quite fragile. using the s  iv, s  v and s  vi mass loss diagnostics, we have determined the mass loss rate of sulfur in the winds of o4  o 6 stars with massive winds, using both lmc and galactic stars, using the sei code ( lamers et al., 1987 ) and rotationally broadened tlusty models for both the uv and euv continua.the results are similar to those determined by the p   v analyses. however, clumping and porosity can influence the results, and must be incorporated into the analysis to determine exact factors.
we report the magnetic field and temperature dependence of the optical coherence in an erbium - doped rare - earth - ion ( rei)-doped fiber with long - lived persistent spectral holes.   the fiber is cooled to a minimum temperature @xmath2  mk in an adiabatic demagnetization refrigerator, resulting in an optical depth of @x Math3 at a wavelength @x math4  nm.    we find that the best coherence properties exist at weak magnetic fields of around 0.05  t that also correspond to the optimal configuration for persistent spectral hole burning in this material @xcite. using two pulse photon echo ( 2ppe ) measurements including the observed non - exponential echo decays in the context of spectral diffusion, we present a detailed analysis describing the observed behaviors that combines elements from theoretical and semi - empirical models that have been developed in the past for glassy and crystalline hosts. in agreement with results of previous studies  , we found that coupling with two - level systems ( tls ) significantly limits the coherence lifetimes to less than 1@xmath1s even at high magnetic fields and temperatures as low as 600 mk. however, an
a torque oscillator ( sto ) is a nanoscaled device that utilizes a dc current through a magnetized magnetic multi - layer structure to yield a steady - state voltage oscillation.   it is composed of two magnetic layers, the " free " layer ( fl ) and the " polarizing" layer ( pl ), being decoupled by a non - magnetic ( nm ) " spacer ". in this multistep structure,   a spin - polarized current transfers angular momentum from the pl to the fl, so as to exert a torque on the local magnetization of the fl. by using this transferred torque to compensate the magnetic damping of thefl, magnetization dynamics can be sustained at microwave frequencies. here  , we report the design and characterization of a new type of stos using an insulator as the spacer for the generation of rf voltage in the microwave range @xcite-@xcite under a specific biasing condition. with the use of a single - walled carbon nanotube ( cmos ) system, we show that the stos can be used as up - converting mixers without the need for a local oscillator, frequency detectors, magnetic field
the orientation of s orbit is a topic of debate in the study of the homunculus nebula @xmath6  carinae, a highly eccentric colliding wind binary with an orbital period of @xcite.   recently, we used asymmetric variability seen in near - ultraviolet ( nuv ) images obtained with the _ hubble space telescope _   advanced camera for surveys / high resolution camera ( _ hst _ acs / hrc ) to constrain the 3-d orientation of its orbit using a hydrodynamical model of s binary colliding winds. here  , we show that the orbital orientation derived by this model is consistent with the asymmetric nuv variability observed in the f220w filter images of  presented in the recent issue of the journal of astronomy and astrophysical sciences. however, the model differs in a key respect, accounting for the wind - wind collision ( wwc ) cavity created by  in s dense wind (@xcite ; ). at phases near periastron,   the cavity reduces the h and optical depths in line - of - sight to  and causes a bore - hole effect @xaite, wherein the wWc
we have carried out an extensive near - infrared survey of fields centered on southern ultra - compact h  ii regions detected at far - infrared and/or radio wavelengths, with sofi on the eso _ new technology telescope.   these narrow - band imaging observations have revealed embedded, young stellar clusters ( @xmath7  magnitudes ) containing newly formed massive stars. in the past decades   significant progress has been made in unraveling the formation process of low - mass stars, but it is not well understood how massive stars form. to understand the formation of the most massive stars, it is important to know how they form. here   we describe the results of a high - resolution ( r=10,000 ) k - band spectroscopy study of members of those clusters using the isaac mounted on the vlt. the spectroscopic targets have been selected based on their @x Math0-band magnitude and @x math8 color.    spectra have been taken of the brightest and most reddened cluster members. erythema and emission lines are dominated by nebular emission from the uchii region, whereas the spectrum features of the late - type ( fore- or background )
sonic crystals have been proposed as artificial structures for attenuating and filtering sound waves because of their acoustic bandgaps@xcite.   the use of sonic crystals below the homogenization limit has been boosted in recent years due to the possibility of using them as an artificial structure with extreme homogenized properties, referred to as acoustic metamaterials, behaving as broadband anisotropic fluids, or metafluids @xcite.in this work, the theoretical formulations and parametric characterization of two - dimensional ( 2d ) sonic crystals with thermovisous losses are presented and verified with numerical simulations. these confined sonic crystal structures exhibit a lossy behavior due to thermal and viscous boundary layer effects within the sonic crystal lattice, which can be explained by the increase in the effective viscosity and the decrease in the bulk modulus due to a change from adiabatic to nearly isothermal conditions within the crystalline sonic crystal. however, the behavior of these confinement structures experimentally is demonstrated experimentally in an acoustic impedance tube, and the theoretical formulation is used to facilitate the design and realization of soft acoustic metameraterials with complex - valued effective material properties, enabling better impedance matching and
we present a large multi - epoch, multi - frequency data - set of space vlbi images of the bl lac object markarian 501 ( b1652 + 39 ) at 15 and 22ghz from three different epochs : 1997.8, 1998.4, and 2001.3.   these observations are used to study the pc - scale jet morphology, velocity and orientation of the central core region of this active galactic nucleus. in particular, we focus on the properties of the outer jet, which is known to be in motion, sometimes with an apparently superluminal velocity. using previously published data as well as new data from two new observations, we show that the jet is in motion at all frequencies studied in this paper, but its proper motion is not always found to be consistent with the currently accepted unified models. by comparing the results obtained at different frequencies with similar resolutions,   we can also perform spectral index mapping for comparison with the total intensity images.
the final merger of two black holes in a binary system releases more power than the combined light from all the stars in the visible universe.   this vast energy comes in the form of gravitational waves, which travel across the universe at the speed of light, bearing the waveform signature of the merger. since template matching forms the basis of most gravitational - wave data analysis, knowledge of the resulting merger waveforms is crucial. calculating these waveforms requires solving the full einstein equations of general relativity on a computer in three spatial dimensions plus time. as you might imagine, this is a formidable task. in this article  , we review the recent breakthroughs in numerical relativity that have yielded robust and accurate simulations of black - hole mergers for the first time, highlighting key applications to astrophysics and gravitational -wave data analysis.
we present a simple and practical method for measuring galaxy evolution in deep space images, by constructing empirical " no - evolution " fields of galaxies as a benchmark, matched in image properties to the data, in this case the hubble deep field ( hdf ).   we first establish the k - correction for each pixel belonging to a given galaxy image drawn from a complete sample of relatively bright galaxies with redshifts ( selected from the hdf universe ), selected from a set of galaxies with high redshift ( @xmath10 ) and low angular size (@xmath11 ), which are both well within the photometric limit of the hfds. using these parameters, we estimate the integrated ultraviolet ( uv ) luminosity density of the inner regions of the galaxies at high - z. the results are compared with local estimates from h@x Math15 emission, which provide an indirect means of estimating the evolution of the integrated uv - luminosity densities of the same galaxies down to the lyman limit. our method is free of the usual limitations of parameterizations, such as the need for star - forming regions to be observed in the uv and the presence of plumes or plumes of
the transport properties of a quantum wire connected to fermi liquid leads are quantized by the quantum of conductance.   this quantization of the conductance has been reported in various experimental setups since its first observation in a quantum point contact with carbon nanotubes ( @xcite ), but it is not always consistent with the luttinger liquid theory. in this paper   we show that even when the backscattering processes can be ignored, the non - uniformity of the interaction potential throughout the wire leads to a finite resistivity at non - zero temperatures. using the model of a one - dimensional system in which the interactions are limited to a small region between two non - interacting leads, we qualitatively show how some of these processes give rise to an inhomogeneous resistivity and perform the corresponding calculation in the language of the inhomogenous lutginger liquid model.. we also present an alternative derivation of the resistivity in the context of the lutsurfer liquid model, allowing us to compare our results with previous works relying on this formalism.
chiral symmetry, as one of the symmetries of qcd, is a key to understanding the dynamics of the strong interaction.   the present paper is based on this point of view, where we extend some previous work by christos  @xcite for @xmath6, to include chiral  mirror " nucleon fields, with a view to ultimately extending it to @x Math7.. the choice of chiral multiplets is perhaps the simplest one consistent with qcd. in the broken symmetry world the chiral structure of the interpolating field is not identical to that of the physical state that is coupled to the field ; generally, the latter could be more complicated than the former. here  , we use the @x maths2 and @x math14 chiral transformation properties of the two independent local nucleon Fields to write down and classify the possible nucleon - meson interaction terms in the present study.    we find that the most important problem is the identification of the three valence quark component in the nucleon states.,we also find that certain characteristic problems become clearer without the algebraic complexity of the@xmath7 case.
comets are frozen reservoirs of primitive solar dust grains and ices. analysis of the composition and size distribution of cometary dust grains from infrared imaging and spectroscopic observations expedites an appraisal of the physical characteristics of the solid materials that constituted the primitive solar nebula @xcite.   we present images and spectra of comets 2p / encke, a 3.3  yr period, jupiter - family comet with a perihelion distance, @xmath3  au, known for an abundance of large dust particles@xcite ; 67p / churyumov - gerasimenko ( 67p ), a j Jupiter -family comet and the primary mission target of the european space agency s _ rosetta _ spacecraft ; and c/2001  ht50 ( linear - neat ) ( ht60 ), an oort cloud comet, @ xmath6  yr, @Xmath7  au. in this study, we show that the mineralogy of the coma of comet encke is dominated by large particles at 2.4  au and that the temperature and effective size of the nucleus of Comet encke are similar to those of other comets.
we investigate the thermalization of open quantum systems by means of a statistical formulation of equilibration in the realm of quantum mechanics.   we consider the situation in which a closed quantum system can be decomposed into two parts, an open system and a bath, and investigate the equilibrium state of the subsystem @xmath0. we find that small system - environment correlations, together with small changes in the environmental state, generally lead to an equilibrium state that hardly depends on the initial state ( or reduced state ) of the open system. however, the interaction induced correlations built by the dynamics play a role which is in a sense opposite to that of the entanglement in the energy eigenbasis. for this reason  , we refer to this mechanism preventing thermalization as information trapping.
microscopic flows of liquids in microscopic channels have been attracting increasing interest recently due to the fast development of microfluidics and soft lithography.   the microscopic flows are almost universally laminar, with linear dependence of the flow rate on the driving force and usually remain steady as long as the driving forces do not change. a few techniques have been proposed to generate stirring by a three - dimensional flow in order to increase the rate of mixing in the micro - channels. here   we present a new method of mixing that involves special " herring - bone " patterning of a micro - channel wall to generate fluid motion perpendicular to the main flow direction in the linear, low @xmath0 regime in the presence of flexible high molecular weight polymers to the working liquid.we show that the non - linearity of the polymer contribution to the stress in the flow can be controlled by raising the reynolds number to moderately high values in curvilinear three - dimensionally curvilinsear flows of viscous polymer solutions at the temperature range of 0.5 to 10 k. the effect of the elastic polymer stresses on the mechanical stress in these flows is more pronounced in the absence of the shear
we explore the phenomenology of other states that can be expected to accompany the exotic quarks in a non - supersymmetric ultraviolet ( uv ) completion of the twin higgs ( th ) model, where the top and gauge partners are complete singlets under the standard model ( sm ) color symmetries.   we focus primarily on the mirror partners of the exotic fermions, which are vector - like ` exotic quark'particles that carry twin color and standard model electroweak charges. as a consequence, they can be produced with large rates at the large hadron collider ( lhc ) or at a future @xmath15 tev collider, depending on their masses. by construction,   the lowest - lying state in th is very challenging, and rare decays of the higgs into long - lived twin particles typically constitute the most promising signatures.. however, these signals display a strong sensitivity to the unknown parameters of the model that limits to some extent their robustness.    in this paper, we show that the spectroscopic properties of the bifundamentals under the color and twin gauge symmetrieves of the fraternal th model @xcite
the dark matter search at colliders is based on the production of standard model ( sm ) particle(s ) with missing energies.   the dark matter production associated with a heavy quarkonium at @xmath0 factories, whose center - of - mass ( cm ) energy is @x Math6 gev, is one of the most attractive scenarios for the search for dark matter at collider experiments. in this paper  , we propose to use the process of dark matter produced from the decays of a light meson and a very heavy quarks to search for non - baryonic dark matter by using the process as a model for the weakly interacting massive particle ( wimp ) scenario where the particle with weak scale mass and interactions could be thermally frozen out and its abundance would be the observed dark matter relic density  @xcite.
feshbach resonance@xcite has been observed in a few alkali systems.   the observation of oscillations between atomic and molecular states indicates macroscopic occupation of molecular states. in this paper, we study the complete excitation spectrum and the decay process of a two - channel model of a dilute bose gas with a large and positive scattering length @xmath3 in the presence of a feshbach resonant state by using a simple saddle - point method to study the dynamics of the correlation between the condensates and atom pairs. at zero temperature in the dilute region,   both atoms and molecules condense, and the chemical potential is the dominant contribution to the condensation. when the density of the atomic condensate is of the order of ~2.5  kcal / mol, the effective coupling constant of the atoms is proportional to the scattering length. for the system with a larger scattering length, the interparticle distance is much smaller than that of the system without a resonance, and it is found to be stable in the space of atom pairs with opposite momentum. however, the solution of the equations of the interaction between the atom pairs and the molecular states is not stable in
we use the parameterized resonance  scattering synthetic  spectrum code to fit all of the spectra of type   ia supernovae ( sne  ias ) that are available to us.   we find that the sn  1994d supernova, a well observed, spectroscopically normal sn 1994d, has a distinct spectral signature that is different from that of most other sn  iales. in this article  , we present an ensemble of  fitting parameters that will provide an internally consistent quantification of the differences among sn  1998a, sn  1999a, and sn  2000a.the best fitting parameters are obtained for the ca  ii h&k blend ( @xmath0weighted rest wavelength 3945 ) in the blue and the ca - ii ir3 triplet ( ca ii ir3 ; ~8579  in the red ) in both the near and near  maximum epochs of sn  94d, and for the c   ii h & k blend ( > 3945  at day  12, then ~3945  on day  115 ) in each of the late  time spectra. using the fitting parameters, we
the proposed re  evaluation of cosmological measurements on the basis of a universal infinity scale determined by primordial inflation leads to a new model of the universe which is dominated by a mysterious form of " dark energy" that violates the strong energy condition.   this model is based on the assumption of an isotropic homogeneous geometry, in spite of the fact that at the present epoch the observed universe is anything but smooth on scales less than 150300 mpc. in this essay  , i argue that this model fails to account for the unique relativistic aspects of gravitational energy associated with spatial curvature and geometrodynamics, which are not included in the quasilocal formulation of the friedmann  lematre  robertson   walker ( flrw ) equation derived from the cosmic microwave background radiation. since the laws of physics must coincide with those of special relativity at a point, it is only internal energy that can be localized in an energy   momentum tensor on the r.h.s.  of the einstein equations. as a consequence,   the model assumes that all observers in the universe should measure the same volume  average position, even if
standardised type - ia supernovae ( snia ) have been extensively studied to probe the expansion of the universe for the past decade.   a better knowledge of their environment and of their host galaxies is important to understand possible systematics, which could affect these cosmological probes and progenitor systems. in order to better understand the nature of these hosts, we try to observe the co lines of sn1997ey host, whose continuum has also been detected at 450 @xmath1 m at the @xmath9 level. using data archives from the keck telescope and the iram-30 m telescope, we show that this host galaxy is a submillimetre - bright galaxy with a star - formation rate of about 1.5 times higher than that of the nearest compact disc galaxy. on the basis of the observed co lines, we derive estimates of the metallicity of the host galaxy and of its star - creation rate. by comparing the measured flux and the measured luminosities, we find that the star -formation rate of this galaxy is much lower than that predicted by a flat cosmology, and that it is more likely to be a matter - dense galaxy. according to the
the quasinormal modes ( qnms ) of spacetimes containing black holes have been studied since the pioneering work of vishveshwara @xcite.   hod s conjecture has been proposed for the asymptotic frequency of the qnm of a schwarzschild black hole in the limit of highly damped modes, and it has been suggested that this frequency should be equal to classical oscillation frequencies of the black hole. however, a large number of papers related to hod's conjecture, which have recently appeared, suggest that hod’s conjecture is not universal, at least as it stands, even though it is applicable for schwarZschild black holes in four and higher dimensions. in this paper, we explore a problem whether or not there is another black hole spacetime in which hod ‘s conjecture does not apply.    we find that the qnm of a reissner - nordstr " om black hole appears not to go to any constant value in the limits ofhighly damped mode, but shows some periodic behaviors as the imaginary part is increased.. we propose a new model for the quantum theory of a black hole with a real
the pythia event generator is a new tool for the simulation of the quark - antiquark annihilation subprocess of the hadron - hadron collision at high energies.   the results of the previous analysis of the three reactions of the annihilation at rest with the three mesons production in the final state of the @xmath6/@xmath5 system, done at lear at cern, have been used to develop new 3- and 2-dimensional plots that show different kind of correlations between the distributions of lepton pairs produced in the collisions of the antiproton beam with the proton target at 14 gev energy ( that corresponds to the center of mass energy of the observed resonant structures ) and the distribution of the free particles in the total energy range of @x Math10=14 gev. here   we present a number of new plots that are based on the perturbative qcd amplitude of the #0 subprocess, implemented into the pythian event generator @xcite, which allows a proper account of the relativistic kinematics while simulation of some physical variables, connected with the pair of quark pair annihilation, in the case of the protons produced in
the present universe shows a variety of structures.   how such a structure is formed in the evolution of the universe is one of the most important questions in newtonian cosmology and general relativity. in this paper  , we discuss how to improve the lagrangian approximation of the density perturbation approach in the framework of newtonians. by including a backreaction term to averaged expansion rate, we show that the Lagrangian approach can be used to estimate the averaged variables in a local domain without taking into account the backre reaction term of inhomogeneities on averaged expansion.
the theory of the localization of eigenfunctions in amorphous solids at low values of the external strain is presented.   it is shown that the lowest energy eigenfunction can be localized in the form of a plastic event that changes the local organization of particles through the creation of essential non - affine displacement. here   we consider two systems of glass formers, which are athermal ( at temperature @xmath2 ) and strained quasi - statically ( with quasi - static loading ), and show that the fundamental plastic instability can be modeled as a system spanning event of shear localization along a line in 2-dimensional systems @xcite and a plane in 3- dimensional systems @xaite. for the latter case,   the localization is realized by organizing the inclusions on a line ( plane ) in 2 ( 3 ) dimensions that are precisely at@xmath8 with respect to the principal stress axis.. the spatial organization of the eshelby inclusions is then analyzed in terms of the properties of the geometry of the solution for the fundamental Plastic Event.
the critical temperature and the second critical magnetic field are some of the key characteristics of a superconductor.   these parameters depend on an effective coupling constant with some collective excitations, on frequency of the collective excitation and on ginzburg - landau ( gl ) parameter. in this work   the pairing of massless dirac electrons and holes located on opposite surfaces of thin film of three - dimensional topological insulator is considered. in such a system both electron - hole coulomb attraction, which leads to pairing, and tunnelling ( or hybridization ) of the electrons between surfaces, which lead to appearance in hamiltonian the " sources" of cooper pairs, act jointly. at @xmath31 the hybridization leads to the smearing of a phase transition into the paired state in close analogy with the behavior of a ferromagnetic in an external magnetic field. in order to reach room temperature such values of the coupling constant are necessary which are not possible in real materials.
we study a nonminimal einstein  yang - mills theory with @xmath1 symmetry and a wu - yang type ansatz.   the general formalism for this theory is set up and the reduced master equation is presented. in particular, we investigate the properties and the horizons of the exact solutions of a gauge field of magnetic type satisfying the wu-yang ansatz for a regular magnetic black hole with a regular center asymptotically de sitter ( ds ), flat ( flat ), or anti - de sitters ( ads ). depending on the sign and value of the cosmological constant the solutions are asymptic, flat, or ad - like. if the dark energy is indeed a cosmologic constant term then our study displays the role of the dark energies in the regularization of the internal structure of black holes.
the sagittarius ( sgr ) dwarf galaxy was recently discovered in the outer regions of the galactic bulge, and is currently being cannibalized by the milky way s tidal field.   the existence of a bifurcation in the leading tail of the sgr dwarf galaxy s remnant core plus stellar stream suggests that the star - stripping process began several orbital periods ago, but the age of the stream has been difficult to explain. here  , we use a n - body model to reproduce the existing observational data on the position and velocity of the biforcated sgr stream, and show that the two arms are both leading the galaxy, and arise naturally during consecutive pericentric passages, which occur at different orientations of the Sagittarius disc relative to its orbit. furthermore, we show that internal rotation can efficiently alter the trajectory of the streaming stream with respect to the orbit of sgr, which might indirectly affect any constraint on the shape of the Milky way s dark matter halo derived from pressure - supported dwarf spheroidal galaxy ( dsph ).
discretizations are very commonly used as a tool to treat field theories.   classically, when one wishes to solve the equations of a theory on a computer, one replaces the continuum equations by discrete approximations to be solved numerically. at the level of quantization  , lattices have been used to regularize the infinities that plague field theories and this has been a very successful approach for treating yang   mills theories. in this paper   we propose a new scheme for discretizing general relativity in order to quantize it. in particular, we show that the lapse and the shift need to be considered as some of the variables to be solvated for in the consistent discretization scheme @xcite.
magnetic fields are being detected more and more routinely at the surface of many stars, and are responsible for various physical phenomena likely to deeply modify our traditional vision of stellar evolution, especially during their early and late stages.   magnetic fields are also an important actor in main - sequence stars, as revealed by @xcite. here   we show that a non - axisymmetric, non force - free magnetic configuration in equilibrium inside a conductive fluid can be found in rotating stars where rotation is uniform, which could be the case if magnetic field is strong enough, and where meridional circulation can be neglected ( i.e. when the star does not loose angular momentum and has a stationary structure ). using numerical simulations, we find that this configuration is a generalization of the taylor state in a stellar context, where the stratification of the medium plays a crucial role. on the one hand, it is a consequence of the presence of a strong magnetic field, and on the other hand it is the result of a relaxation process involving magnetic reconnections between the field and its host material. with respect to the rotating case,   this family of equilibria is characterized by a large - scale magnetic
the rayleigh - taylor instability is a classical hydrodynamic instability in which a layer of liquid is superimposed to an immiscible and less dense liquid such that the potential energy of the system can be reduced by interchanging the liquids.   it is well known that the instability may be suppressed by vertical oscillation or by appropriate temperature gradients. in the present paper   we investigate the possibility to stabilize a potentially rayleigh-taylor unstable system involving a magnetic fluid by external magnetic fields. for experimentally relevant parameter values moderate fields strengths which can easily be switched on and off are sufficient to achieve the desired stabilization.
the recent observation that the fine - structure constant was smaller in the past than it is today has led to renewed interest in the idea of using time ( and space ) variation of fundamental parameters as a probe of high - energy physics. in this work   we will critically analyze the two - nucleon sector using an effective field theory ( eft ) that respects the approximate @xmath3 chiral symmetry of qcd and has consistent power - counting.   this theory allows for a systematic study, consistent with qcd, of the bound - state in the @x Math4 coupled - channels, the deuteron, and the scattering amplitude in the@xmath5 channel. at next - to - leading order ( nlo ) in a consistent eft, the binding energy of the deutero - quark masses varies relatively little, and for which the di - neutron system in the #5 channel is unbound, over a relatively wide range of quark mass.
spin - polarized scanning tunneling microscopy ( sp - stm ) and spectroscopy ( sts ) are nowadays the key tools for nanomagnetic research, i.e.  for studying and manipulating magnetic properties of surfaces and deposited magnetic nanoclusters with atomic scale resolution.   it has been established that the tip electronic structure plays a crucial role in measured differential conductance ( @xmath0 ) tunneling spectra, which can be tuned by changing tip magnetization direction or bias set point for the tip. here   we investigate the effect of effective spin - polarization on the sts spectra of the magnetic fe(001 ) surface by simulating differential tunneling spectrum of the same surface using first principles electronic structure calculations based on the transfer hamiltonian approach. as a result  , we show that the effective spin-polarization of the tip is an important factor in the influence of the tunneling current on the fs spectra. to test this hypothesis, we study the effects of different tip orientations and bias set points on the ms spectra from a ferromagnetic ni tip at different bias voltages and find that the results are not only consistent with the theoretical model of sp - sts
the high energy limit of perturbative qcd scattering amplitudes is generally given in terms of high energy factorization and the bfkl evolution.   the latter resums large logarithms in the center of mass energy @xmath0 at leading ( ll ) and next - to - leading logarathmic ( nll ) accuracy @xcite. here   we give a prescription for higher order induced vertices in the gauge coupling which respects the symmetry properties of the unregulated vertices and which can be motivated through the high energy expansion of qcd scattered amplitudes. using this prescription we provide explicit results up to the order@xmath3 induced vertex which can then be directly used for calculations within the effective action such as the determination of the gluon part of the 2-loop quark regge trajectory, corrections to gluone induced production processes and studies of multiple reggeized gluons exchanges.
we present a new set of network coding bounds for general broadcast networks that rely only on the cut structure of the network.   the bounds are based on the fact that the set operations within the rate and the capacity functions are _ identical _ ( but not just the union any more ), both similar to the case of standard cut - set bounds as in. from these bounds, we show that the network can achieve the entire capacity region when there is only one multicast message at the source node and when there are only two sink nodes.
the diffuse intra - group light ( igl ) component is a useful tool to measure the intensity of the tidal interactions suffered by the galaxies and to map the extension and shape of the group gravitational potential and the dark matter halo.   we have studied 3 hickson compact groups ( hickson 1982 ), in different evolutionary stages, as a pilot study for an igl survey. using the "  trous" wavelet transform with a multi - scale vision model ( ov_wav  epitcio pereira, rabaa & da rocha 2005;da rocha & mendes de oliveira 2005 ), which does not depend on " a priori " information, we have detected igl in hcg 79 and hcG 95.. non - detection of igl has been reported in hCg 88 indicating an early stage of dynamical evolution.
the reconstruction of the higgs potential is an experimental  prima facie  task to establish the higgens mechanism as the basic mechanism for generating the masses of the fundamental particles.   this task requires the measurement of the self   couplings of the human higgs particles. in the present paper   we have analyzed the production of pairs of neutral higgs bosons in gluon   gluone collisions at the lhc using the minimal supersymmetric extension of the standard model ( mssm ) and the light   energy proton beam decay mode at the lep @xcite. by measuring the decay branching ratios of the continuum and resonance decays, we have determined the cross sections of the trilinear and quartic couplings in the standard models and the continuum/resonance decays in the msmsm. from the results   it can be concluded that the lifetimes of the two  loop couplings depend on the mass of the physical higgs particle and the mixing angle of the collider.
the properties of quantum antiferromagnets in low dimensions have been intensely studied over the past decade and a half.   most of this work has been done using large @xmath0 treatments based on generalizing the symmetry group from su(2 ) to either su(@x Math0 ) or sp(@Xmath0 ), especially in two dimensions where exact solutions are not available. at @x math9   the constraints are trivially solved and a purely quadratic problem results. here   we investigate the fate of a phase transition between the perfect paramagnet and ferromagnetic state at finite @x maths0 that occurs in the su@xmath2 generalization of the heisenberg ferromagnet at @ x = 0.9. for the first time we show that the transition is first order on a square lattice and that it is continuous on all lattices that have a shortest closed loop of length three or four. by taking the large " spin" or boson density limit at any fixed @xMath0  , we render the problem classical without destroying the transition of interest.
we have developed a formalism which allows the differential scattering rate over energy and angle to be determined from any incident distribution, including anisotropic ones.   we then explore not only the predicted distributions, but also the ability, given a fixed number of events, to unambiguously demonstrate evidence for underlying directionality in the events.
the heating of the sun s chromosphere requires more than an order of magnitude more mechanical energy flux than the corona and heliosphere combined @xcite.   nevertheless, the heating mechanism powering the chromosphere remains elusive, especially in the magnetic chromosphere in and around network and plage regions. here   we report on new observational constraints on chromospheric heating derived from the  @xmath0 spectral line using full - stokes data from the swedish 1-m solar telescope ( sst ). by analyzing the spatial and temporal properties of the raised - core ( rc ) profiles, we show that they are found in the vicinity of strong magnetic fields, and that they have a very peculiar spatial distribution. to explain the observed profile shapes, we propose a scenario that explains the profile shapes using synthetic spectral line profiles from a 3d radiative magnetic field density ( mhd ) simulation.
the spin-1/2 ising - heisenberg model on triangulated ( triangles - in - triangles ) planar lattices has attracted a great deal of attention recently, because it closely resembles the magnetic structure of real polymeric coordination compounds cu@xmath0x@x Math1(cpa)@x maths2@x math3nh@xMath1o ( x = f, cl, br ) with the geometry of triangulate kagom lattice.   the exact solution of the spin- 1/2 areing -Heisenberg models on the husimi lattice can be viewed as a general approximation of the ising model on the bethe lattice, whereas the interior part deep inside of such recursively built tree is usually referred to as the husimic lattice.in this paper, we present a detailed analysis of the ground - state and finite - temperature phase diagrams of the Spin-1/.   our results show that the local quantum fluctuations of the underlying triangular lattice give rise to a remarkable quantum order at low enough temperatures instead of a quantum disorder through the order - by - disorder effect, which is consistent with the observation that the spin
low - luminosity active galactic nuclei ( llagn ) are a group of galaxies with emission - lines similar to those seen in active galactic nucleus ( agn ) but on a much lower level.   the nature of the activity is largely unclear, but it has been proposed that the emission could be produced either by an advection dominated accretion flow ( adaf ) or from scaled - down agn jets. here   we have performed a vla survey of two samples of nearby galaxies with optical emission -lines to identify compact radio cores with high brightness temperatures and follow - up observations with the vlba of these cores have been made that shed further light on their nature.
we investigate the capacity - achieving transmission strategy for a half - duplex amplify - and - forward ( af ) relay link with a single antenna at the source and one at the destination in a multi - antenna relay system.   we use a nonconventional powerful approach based on one of the stochastic orders, the _ laplace transform order   _  @xcite, which circumvents the requirement of concavity to obtain optimal source precoding matrix ( or equivalently, the covariance matrix ). using this approach,   the maximum ergodic capacity of the source - relay link is found to be 1.5 times that of the relay - destination link, resulting in a mean - square error rate of 0.8  0.2  v / m2/s for the backward channel and 0.9  0% for the forward channel.    the result is attributed to the use of channel mean feedback, which is provided to the source by the relay as a means of improving the information about the channel state information available at the transceiver.
directional detection of weakly interacting massive particles ( wimps ) using liquid and solid - state detectors is a key goal of the field of dark matter particle physics.   experiments are typically performed using gas time projection chambers ( tpcs ), which contain low pressure gases such as cf@xmath2, cs@x math3, c@x maths2h@x Math4 or @xmath5he. in this paper   we examine the capabilities of future directional dark matter detectors to detect a dark matter stream in the form of tidal streams, which result from the disruption of sub - halos accreted by the milky way. for each detector, we calculate the directional event rate, including the relevant particle physics and astrophysics input, and use non - parametric directional tests to test the ability of the detector to detect the stream.. the results show that the experimental event rate can be used to infer the shape of the local wimp velocity distribution, with the best fit to the predictions of the standard halo model ( shm ), but the accuracy of the calculations is limited by the presence of free parameters on which it depends. however, if the free parameters are
the condorcet jury theorem is a mathematical formulation of the requirements for optimal decision making.   it is one of the original formal justifications for the application of democratic government structures in the context of the age of enlightenment, a period when prominent thinkers began to question traditional forms of authority and power and the moral standards that supported these forms. while modern democratic governments strive to achieve the ideals of the enlightenment, it is put forth that governments can better serve their citizens by making greater use of the technological advances of the present day information age.
we describe a two - dimensional surface structure that produces asymmetric transmission of surface plasmon polaritons ( spp ) when they are incident on it from opposite directions.   the structure consists of a metal - air interface where the metallic region is formed by two metallic segments whose interface between them is periodically modulated by periodic changes in the period of the interface and/or the angle of incidence, and this can be controlled by varying the time of the modulation process. using a theoretical approach based on the thin phase screen model  , we show that the zero - order term in the fourier expansion of the transmitted electric field can be suppressed in a certain frequency range when the interface has the form of a rectangular grating with a critical value of the amplitude modulation depth. to achieve this,   an additional diffractive structure is added to one side of the structure which allows the transmission of the + 1 and -1 modes through the structure without the need for either electrical nonlinearity or the presence of a magnetic field.
wave packets are a standard tool employed to explain many different features in chemistry and physics, e.g., chemical reaction dynamics, oscillatory motion of a coherent bose - einstein condensate, highly - excited rydberg states in atoms, or electron - hole excitations in semiconductors.   the concept of wave packets is sometimes applied to rationalize experimental data even though the reaction occurs under condensed - phase conditions, where the relevant reaction coordinate may be strongly coupled to other modes ( " environment" or " bath " ). here   we show that the dissipation acting on the wave packet can have many different microscopic origins. in gas - phase reactions,   one typically has rather weak damping due to coupling to the vacuum modes of the electromagnetic field ( spontaneous emission ) or due to collisions with other molecules. in contrast, dissipation can become decisive in condensed -phase reactions where one has strong coupling of the system to solvent or protein polarization modes. as a practical example  , we analyze the recent stimulated emission experiments of the bacterial photosynthetic reaction center by vos _   selenium sulfate ( vossec ) by using pump - probe spectroscopy.
the influence of the effective viscosity in the lateral interaction between the jet and its external medium on the stability properties of relativistic jets has been investigated by means of hydrodynamic simulations.   the results show that, in the non - linear regime, the velocity of the jet core smoothly decreases until it vanishes at the external medium, whereas in the linear regime the radial velocity profile is roughly monotonic. as the jet flows into a viscous medium,   an eddy shear layer forms around the jet surface, which spreads into the flow and leads to the entrainment and acceleration of ambient gas. for the first time  , we have studied the effects of this boundary layer on the strength of the kelvin - helmholtz ( kh ) instabilities in the extragalactic jet with respect to the spin - sheath magnetized, spine - sheaths magnetized model of the relativism jet. using a combination of experimental and theoretical data, we show that the effective vesicle viscosities of the two models are differentially affected by the existence of a turbulent eddy layer and the presence of a parallel magnetic field near the jet boundary. from a theoretical
the quantum stein s lemma characterizes the optimal rate exponent under which the average error tends to @xmath3 in the setting of asymmetric hypothesis testing.   it states that the maximal exponent of type  ii error is the quantum relative entropy, given by the stein - lemma. here  , we prove the second - order asymptotic theorem, and thus fundamentally refine the quantum steins lemma.we track the exponent of the rate exponent of types  i and ii error quantified by its first order from the smaller side to the larger side using a series of simple linear equations. for each case, we find that the optimal type  i error jumps sharply from @xmath2 to  @x Math3 when the rate exponents of type 1 and 2 error pass by the relative entropy. for type 2 error,   the optimal time course is much more complex, and the rate constants of the two types of errors are not the same. however, they are very close to each other in terms of both the size and the order of the error. on the other hand, for type 3 error, the optimal timescales are much longer than those of the other two
the baryon asymmetry of the universe was determined at the first order electroweak temperature transition ( ewpt ) @xcite.   this phase transition is studied by means of a combination of perturbative and lattice studies, i.e. simulations of the su(2)-higgs model on symmetric and asymmetric @xmath2-ray lattices with different spacings in temporal and spatial directions. to study the nature of the phase transition for realistic higgs bosons,   an effective three dimensional ( 3d ) theory is constructed by using dimensional reduction, which is a perturbation step ; the end - point of the phases is determined and its universality class is studied from the perspective of the cosmological properties of the u(1 ) gauge group and the fermions. also, the role of the sphaleron rate is discussed.
the casimir force of au thin films is measured experimentally by iannuzzi @xcite using ellipsometry.   the experimental data show that the casimir attraction between a metallic plate and a metal coated sphere depends on the thickness of the coating. in this paper   we introduce a frequency dependent damping in the drude model for thin films, which describes the dielectric properties of the thin films and changes if the film has been annealed. to further the discussion about the possible factors that influence the Casimir force calculations, we also introduce a new model for the relaxation time due to electron - phonon and electron - ion interactions of the form : @xmath3.. the model assumes that in a thin film sample there are two regions labeled@xmath9 and @x Math10.    the electrons respond differently in each of these regions and have a different damping rate, depending on the preparation of the sample. from the measured data,   it is shown that the temperature dependence of the damping parameter can be explained by the existence of a transient relaxation time with the sample, which is caused by the interaction of the electrons with the surface of the material.
the efficiency of optical fiber spectrographs for observing point sources such as quasars is determined by the offset between the fiber and image positions during each exposure.   the aim of this paper is to provide a comprehensive list of the sources of fiber position errors and to quantify their effects on efficiency when fiber spectroscopy is used to observe point sources, including the sdss @xcite and 2df surveys. in order to achieve the best possible efficiencies,   it is necessary to avoid systematic errors in fiber positioning, telescope guidance, seeing conditions and other factors that reduce the signal - to - noise ratio ( snr ) of the reduced spectra. with single - object instruments, these errors are usually small enough to be negligible, but with multi - object instrumentation, the errors may vary systematically across each tile leading to position - dependent selection effects that repeat from field to field. where a survey is constructed from the consolidation of tiled observations, each exposure will be made under different conditions, leading to variations in the rate at which signal is recorded. if the variations in snr are left uncorrected, automated analysis of the resulting catalogs may suffer from very complicated measurement errors, creating problems for the
the forward calorimeter ( fcal ) for the gluex experiment  @xcite in hall d at the thomas jefferson national accelerator facility ( jlab ) is an experiment that will primarily search for mesons with exotic quantum numbers using a photon beam incident on a proton target.   the fcal will be an essential detector for the experiment, providing energy measurements and timing information for photon showers in the forward region with polar angles @xmath4 and energies between 100  mev and 5  gev. in the fall of 2012, a 25-element miniature version of the f Calorimeter was constructed for a beam test underneath the existing photon tagger of hall b @xcite at jlab. during the beam test,   each of the 25 modules was mounted in a light - tight aluminum body, with a gear drive that allowed the modules to be tilted at an angle so that the front face of the module was facing the center of the beam while the back face was facing away from the beam. as expected, the main goals were to verify that the hardware configuration of the Fcal modules would meet the desired energy and timing resolutions and to validate the design of the light collection
quantum simulation is a powerful method for simulating properties and dynamics of quantum systems whether by classical or quantum computation.   the study of quantum simulation focuses on problems that are not amenable to classical methods such as solving the state or determining the spectrum of the hamiltonian over some time domain or finding eigenvectors of the ground state. in this paper   we discuss the advantages of using a quantum computer for quantum simulation of single - body and many - body quantum dynamics, and we present an efficient algorithm for solving one of these problems which is based on the magnus, or baker - campbell - hausdorff, method.
the present paper presents the interior solutions of the gravitational field equations for relativistic anisotropic fluid spheres with variable density.   the solutions are obtained by choosing a particular choice of the mean density inside the fluid sphere. in order to study the stability of the fluid spheres,   it is necessary to obtain the exact interior solution of einstein s field equations using the ad hoc relation between the components of metric tensor and the field equations. according to this methodology, the results of the present paper are as follows : ( 1 ) the first exact solution of the field equation for a compact object in static equilibrium was obtained by schwarzschild in 1916 ; ( 2 ) the second exact solution has been obtained by tolman @xcite by introducing an additional equation necessary to give a determinate problem ; ( 3 ) the third exact solution is obtained by means of several simple assumptions ; ( 4 ) the fourth exact solution can be obtained by considering the presence of anisotropy in the tangential pressure ; ( 5 ) the fifth exact solution shows the existence of a solid core due to presence of the anisotropies in the pressure ; and ( 6 ) the sixth exact solution gives the upper bound of the
we find a recipe for general lattices to discover the ground state spin pattern corresponding to a given set of exchange couplings, to neighbors at successive distances.   we also identify the parameter sets leading to exceptionally degenerate or otherwise interesting states, so as to recognize which real or model systems might be close to realizing those special states.
superconductivity in the copper oxide ceramics ( cuprates ) with an unprecedented high transition temperature @xmath0 is due to a heisenberg antiferromagnetic exchange interaction between electron spins on the @x Math9 atoms.   the superconducting critical temperature rises with increasing hole doping through the underdoped region, reaches a peak at optimal doping, falls away at higher doping, and then vanishes at the maximal doping. here   we review the current understanding of the mechanism responsible for this peculiar doping dependence of the critical temperature and the presence of a pseudogap in the high - temperature cuprate superconductors.
cross - calibration of distance estimators is a key step in the development of new methods for the measurement of h@xmath3.   we compare the results of cross - calibration among distance estimator methods using data from the ned 1-d database and photometry and kinematics compiled within the hyperleda database @xcite to test the hypothesis that the fundamental manifold ( fm ) can be used to trace potential internal dependencies among distance estimation methods, and reverse the calibration and use the fm to obtain distances and estimate @x math3.we find that the most accurate method, the tully - fisher method, is best suited to the study of near and far galaxies, regardless of luminosity or morphological class ; however, the accuracy of the other methods is limited by the fact that they are each applicable to different, narrow classes of galaxies, limited in type and luminosity, and therefore do not resolve the entire problem. as a solution to this limitation, we present a new scaling relation that is applicable to _ all  galaxies, which we call the fundamental manifolds ( fms ). based on the fms, we calculate the weighted average of the mean distance measurements for each of the
the berry phase is a well - known feature of the phase - coherent quantum dynamics of a particle carrying a spin and moving through orientationally inhomogeneous magnetic fields.   we have recently proposed a number of scenarios in condensed matter settings where the berry phases of the spin can be observed in the form of persistent currents or oscillations of the magnetoconductance, e.g., in semiconductors or metals. however, for sufficiently large magnetic fields, the effects appear only in the adiabatic limit, i.e., when the typical orbital frequency of the particle carrying the spin through the field is much smaller than the precession frequency of its spin around the local field direction. in this limit,   the spin will remain in its instantaneous eigenstate and continuously align itself along the _ local _ field direction as it moves through the magnetic field texture. here  , we show that this is not the case, and we discuss the issue of dephasing induced by inhomogeneity of the field. to this end, we provide in the following sections a general discussion on the issue from the context of weak localization physics and then provide explicit examples that unambiguously demonstrate the observ
the relation between entropy production and nonequilibrium stationary states is still poorly understood.   the main focus of this work is to analyze the symmetry of the large deviation function associated with the variation of the interface height using the restricted solid on solid ( rsos ) growth model in the kardar - parisi - zhang @xcite ( kpz ) universality class. for some continuous time markov jump processes an ( average ) entropy production can be defined, and a positive entropy production in the stationary state is a signature of nonequilibria. in this paper   we study how the entropy production varies with the interface velocity and the surface tension of the system. assuming that a nonequ equilibrium stationary state of a kpZ interface is characterized by the parameters @xmath7 and@xmath9, we show that the fluctuation relation for the joint probability distribution of two currents, with one of the currents being the height, can be found and that for the four - site system the large deviations from the gallavotti - cohen ( gc ) symmetry are symmetric. unlike the gc symmetry which results from a certain relation between the rate of each microscopic trajectory and its time reversed one
we study the dynamics of trace distance discord ( tdd ) for special @xmath0 states by considering a dephasing two - qubit system initially prepared to a class of @x Math0 states beyond bell diagonal form.   the necessary condition for the occurrence of freezing tdd is found and compared with that of entropic discord. in this paper, we find that the conditions for the existence of sudden transition and double sudden changes with freezing discord are much weaker than that of freezing entanglement. moreover, the effects of initial parameters and the dipole - dipole coupling between the two qubits on the dynamic dynamics of nonclassical correlations are also analyzed.
dynamics of self - gravitating stellar systems and plasma fluids are governed by the collisionless boltzmann equation ( cbe ) @xcite.   finding a general solution of the cbe has been a challenging problem in various disciplines of physical sciences. due to existing difficulties of the general problem, finding a solution to   the linearized cbe became the center of attraction in the twentieth century. here   we present a new method for solving the nonlinear eigenvalue problem for the differential modes of stellar disks using kalnajs s matrix theory.
supergiant fast x  ray transients ( sfxts ) are a sub - class of high mass x  rays binaries that display rare outbursts punctuated by short ( @xmath01 - 2 ks ) luminous flares reaching 10@xmath210@x Math3  erg  s@x math4, characterized by a duty cycle lower than a few %.   the mechanism responsible for the flaring behavior of these transients, associated with the accretion of matter onto a neutron star ( ns ) by a fraction of the donor wind, has been discussed by many authors. in the present work   we investigate the dynamic range of the three sfcts which show the highest dynamic range (,  and ) and are often referred to as " prototypical s fxts " in the literature. using data from the /ibis public archive, we find that the waiting - time between two consecutive flares and the duration of the brightest phase of the outburst is significantly longer in the most extreme case of the sfxp   @xcite than in the other two sfxfxts ( p<0.05 ).    we also find that
imaging atmospheric cherenkov telescopes ( cts ) have developed rapidly from pioneer instruments to precision observatories for high - energy gamma radiation with a large user community.   these constraints typically lead to a total yearly observation time for any one observatory site of roughly 1000 hours. within this time  , the observer must perform two tasks : the observation of the ( known or suspected ) gamma - ray source ( " on - source " observation ) and an auxiliary " off - source" observation to determine the background caused by hadronic cosmic rays contained in the on-source observation. since the hadronic background is known to be isotropic and time - independent, it is in principle possible to measure the background by taking the off run long before or long after the on run is taken. however, all schemes have in common that they either achieve less than optimal sensitivity or occupy a large fraction of the total observation time, roughly 50%, which reduces the telescope s ability to follow the light curves of rapidly variable sources. in this article,   i propose a new method to obtain Off - source observations sacrificing a smaller fraction of each observation time and avoiding increased systematic uncertainties.
the acceleration of cosmological expansion at present epoch has been the most principal achievement of observational cosmology.   the accelerated expansion of the present universe is attributed to the dominant component of the universe, dark energy, which not only has a large negative pressure, but also does not cluster as ordinary matter does. in this paper  , we review the current state of knowledge on the nature of dark energy and discuss the recent advances in the understanding of its origin.
compressed sensing ( cs ) aims at recovering high dimensional sparse vectors from considerably fewer linear measurements.   the problem of sparse recovery through @xmath6 norm minimization is not tractable. in the present work,   a deterministic construction procedure of binary sensing matrices using euler squares is proposed. here, the advantages of the proposed methodology are as follows :   * matrices of general row size ( different from a prime and its square ) and small density are constructed ; * simplicity in construction is achieved ; * density is defined as the ratio of number of nonzero entries to the total number of entries of the matrix ; * binary matrices being sparse and possessing@xmath8 as elements provide multiplier - less and faster dimensionality reduction operation, which is not possible with gaussian matrices ; * there is a nonzero probability of non - compliance with restricted isometry property ( rip ) for gaussianMatrices ; and   the proposed method is shown to be useful for the purpose of content based image retrieval ( cbir ).
the existence of ultrahigh energy cosmic rays ( uhec ) with energies above 100 eev has been challenged by the discovery of a double digit number of events with an energy greater than 100 mpc, placing the existence of the so - called " gzk effect " somewhat in doubt.   it was suggested that this could be caused by a small amount of lorentz invariance violation ( liv ) and that such a violation might have important implications for some quantum gravity and large extra dimension models. in this paper   we investigate the observational implications of this possible effect using a renormalizable treatment of the free particle lagrangian which is given by coleman and glashow  as a function of the maximum attainable velocities ( mavs ) of the protons. to test this theory, we find that the mean photomeson energy loss attenuation length for protons at energies greater than 50 eev is much less than the visible radius of the universe ( ~0.5 mpc ). on the other hand,   the mean photon production time from the interaction of protons with the cosmic background radiation ( cbr ) is very small ( ~1 s )
the tilted mirror geometry of a pyramidal pit of @xmath190opening angle @xcite is known to be a good model for tunable raman enhancement.   this geometry has reflecting surfaces of a distance that scales between a few wavelengths and sub - wavelength and thus resembles an ( unstable ) optical resonator. here   we investigate the possibility that the enhanced signal is generated by energy coupling into the raman active medium from a high energy standing wave, practically implementing a raman laser. in this case, we approximate the pyramid - type geometry with a v - slit, thus reducing the dimension of the problem to a plane, a simplification that, at the moment, is necessary for the solution of the problems.. the results show that the proposed geometry can be used to implement resonant enhancement of surface enhanced raman scattering ( sers ) on nanovoids such as spheric cavities or grooves.
monte carlo statistical simulation methods are widely considered for tackling problems in the machine learning community, @xcite.   however, when considering common target distributions encountered in the statistics and machine learning communities, the methods are still suffering from some random - walk behavior. in this paper,   we introduce a new event - chain monte car Lo simulation scheme, the forward event - chains monne carlo algorithm. building on the insights brought by@xcite, this method allows for a fast and global exploration of the sampling space, thanks to an efficient implementation of lifting. in addition, it is rejection - free and does not require any fine tuning of parameters. as a proof of concept  , we demonstrate the performance of this scheme for high - dimensional ill - conditioned gaussian distributions, where it exhibits speedups of several magnitudes in comparison to standard event -Chain implementations and hastings - metropolis algorithms.
the quantum discord is a measure of quantum correlations which are not captured by entanglement.   it is defined as the difference between the quantum generalization of two equivalent formulations of classical mutual information. in this paper   we study the time evolution of classical and quantum correlations for a system of two identical qubits under local non - dissipative non - markovian channels. using a well established model describing the dynamics of a two - level system in a dephasing channel in which white noise is replaced by colored noise, we show that the system can undergo a sudden transition between a classical decoherencephase in which quantum correlation is frozen, while classical correlation is lost, and a quantum deco coherent regime in which both quantum and classical correlations are deteriorated at the same time. to explain the transition between the two dynamical regimes  , we propose a new framework for the definition of the quantum discord.
this paper discusses a simple model of an oscillator coupled to a string that presents a host of interesting features in a very accessible way.   it is presented in detail in    ( see figure   ). even though the required technical background is on an upper undergraduate / early graduate level, this model encapsulates many relevant features of physical interest which can be found in more realistic models, for instance when considering the interaction of an atom ( the oscillator ) with light ( the string ).
the radial velocity ( rv ) technique remains one of the most successful methods for the discovery of exoplanetary systems.   the success of this method is greatly dependent upon the ability to accurately characterize the properties of the host star. here   we present new results for the system hd  99492 that reveal an activity cycle in the star and further show that stellar activity amply explains the signature of the outer planet, a 0.1  @xmath5 planet in a 17-day orbit with a period of @x Math05000 days. using a combination of spectroscopy made easy and yonsei - yale model isochrones, we derive a revised keplerian orbital solution for hd99492 that includes a linear trend to account for a possible second companion in the system. from the complete dataset of 130 keck / hires spectra, we find that the activity indices of the star are highly correlated with those of the inner planet, consistent with the observed brightness variations in phase with the orbital period of planet b. photometric data from 5 observing seasons acquired over a span of 11 years confirm the absence of brightness variation in phase at the predicted phase of planetary transit, thus confirming the
we propose a laboratory experiment which requires a highly accurate phase measurement to test the existence of retarded gravitational forces in the immediate vicinity of an oscillating mass distribution.   we consider an idealized experiment consisting of a mass - balanced, mechanical two - body oscillator, which generates disturbances in the space - time metric, and a mechanical oscillator tuned to resonance to detect these gravitational forces at a distance of order from the oscillator source mass. using the dominant part of the linearized einstein equations, we show that the gravitational forces generated by the source mass are instantaneous in the near - field, and that the dominant length scale for the decay of the retardation is given by the oscillation amplitude of the mass distribution ( defined as the distance between the source and the oscillating source mass ). with increasing distance from the source,   the dominant magnitude of the local retardation of gravitational forces converges to zero.
the possibility of a liquid - liquid ( ll ) transition in one - component systems has been the subject of intense research activity in recent years.   water is one of the liquids that might possess a ll transition, and the first conjecture of this was based on a numerical study of the st2 potential @xcite, a model designed to mimic the behavior of liquid water. here   we apply the sedimentation profile method to st2 water, a rigid, non - polarizable, 5-site potential that is able to reproduce qualitatively the thermodynamic anomalies associated with liquid water under extreme thermodynamic conditions. using a semi - infinite simulation box, we find that an interface separating two liquid states appears at low temperature, corresponding to the coexistence of two metastable liquid states of water within one simulation box : the low density phase is formed by an open tetrahedrally - coordinated network of hydrogen bonds, while the high density phase has a more distorted network of hydrophobic hydrogen bonds. these results are consistent with the presence of a ll transitions in the deeply supercooled regime, which is difficult to probe experimentally due to spontaneous crystallization of@xcite.
the galaxy evolution explorer ( galex ) has opened a new era of extra - galactic uv astronomy.   it is surveying the uv sky with unprecedented efficiency and very high sensitivity. in this paper  , we carried out galaxy number counts in the two galesx bands : the fuv ( 1530 ) and the nuv ( 2310 ). for each band,   the number counts are obtained from three data sets : 36 medium - depth survey ( mis ) fields taken from the internal data release ir0.2, 3 deep survey ( dis ) fields from the spitzer first look survey ( fls ) area, and 17174 fuv galaxies and 41512 nuv galaxies from the sloan digitized sky survey ( sdss ) dr1 database. to minimize the artifacts which concentrate near the periphery of the field of view, we include only sources within 0.45 deg radius from the field center, corresponding to a sky coverage of 0.64 deg@xmath7 for each field. using the sextractor / poissonbg pipeline, we find that the mean number counts of uv galaxies in the 2nd band are significantly higher than those in the 1st band.
we develop analytic expressions for option - pricing of markets with fluctuating volatilities of a given distribution.   the gamma distribution (  ) is the normalized gamma probability density, whose profile is shown to be well fitted by a log - normal distribution. in this paper   we show that the same volatility data can be fitted equally well by a chi distribution and that corresponding sample paths follow the additive rather than multiplicative it stochastic process.
the aim of this paper is to investigate the limiting factors to the quality and size of the final image obtained in double - impulse magnetic focusing experiments using pulsed magnetic lenses for weak - field - seeking cold atoms.   we show that the main limiting factors are the spatial performance of the magnetic lenses used, and the effect of the lens potential on the resulting cloud size. a magnetically focused cloud with a bimodal distribution consisting of a highly diffuse outer cloud as well as a core cloud which can be orders of magnitude denser than the initial atomic sample is ideal for remotely loading tight traps with relatively small depth, e.g. miniature magnetic guides, atom chips and optical dipole traps.
we present a proof of theorems  and , which prove that the exponential map of the complex plane is chaotic in the sense of devaney.   the latter is a reformulation of the famous theorem of misiurewicz ( 1981 ), which confirms a conjecture stated by fatou @xcite in 1926. here   we give a brief overview of the history of the proofs of these two concepts, and briefly review the properties of the hyperbolic exponential map as a function of the number of times it is applied to a given set of starting values. using this background material, we show that both the original theorem and the new one are valid, and that the latter requires no background beyond a first undergraduate course in complex analysis.
we present a new approach to the theory of routing in massively dense wireless sensor networks based on road traffic theory.   we study the optimal traffic distribution and to find the minimum amount of relay nodes needed to transport the data from the sources to the destinations in a mobile context where ( i ) only sources are mobile and the destinations are static as it would be in the case when the aggregation centers are fixed and the sensor nodes have the capability to move, ( ii ) both sources and destinations are mobile, and given that the mathematics involve are similar ( iii ) we also analyze the cases when the sources are static and the destination are mobiles. for each of these cases, we find the optimal flow of information and the optimal spatial density of the relay nodes at each period of time. within this context  , we also give an example with numerical results related to the previous mobility setting.
the stewart - lyth inverse problem is a method for the determination of the inflationary potential for the well - known scenario of power - law inflation.   it is based on solving the differential equations for the spectral indices @xcite in terms of the first slow - roll parameter @xmath0 and then finding the proper potential for this scenario. here  , we present a qualitative study of the dynamics described by these equations using the spectra of the boomerang and maxima-1 experiments as parameters. to draw conclusions about the behavior of the general solutions,   the equations are analyzed using the phase space for the second order equation which presents a singularity that strongly determines the flow geometry. except in the case of null tensorial index, the singularity is also observed. for the reduced first order equation, the solution is solved for any value of the tensorial spectral index and the possible behaviors are analyzed with all of the solutions being monotonic. except for the case when the tensial index is null, the results suggest that the proposed method is still valid.
the lifshitz theory of the van der waals forces in the framework of quantum statistical physics is extended to the case of the interaction of atoms and molecules with carbon nanostructures at separations larger than about one nanometer.   the lifshiz - type formulas are obtained for the interactions between a microparticle ( an atom or a molecule ) and a single - wall carbon nanotube using the same model of graphene as in ref.,   @xcite. both the free energy and interaction force at arbitrary temperature are considered. as an example  , we have calculated the vander waals free power and force as functions of separation in the configuration of a hydrogen atom and a molecule in close proximity to a single- and multi - wallcarbon nanotubes.    comparison studies of the effects of separation distance between amicroparticles and multi- and single - walls carbon nantubes are performed.
the phenomenon of zitterbewegung ( zb, trembling motion ), devised in 1930 by erwin schrodinger, has been for the last 80 years a subject of controversy and excitement.   the interest in this phenomenon experienced a strong revival in 2005, when it was demonstrated that the trembling motion can occur also in solids  . however, in the solid state literature the largely prevailing picture is based on the bloch theorem in which electrons are treated as quasi - free particles with a modified ( effective ) mass. to the author s knowledge, there exist only two textbooks discussing an instantaneous carrier velocity in a crystal : " wave mechanics of crystalline solids" by r. a. smith  @xcite and " semiconductor physics" by p. s. kireev @xcite. in this work   we show that the above question is related to the difference between carrier s momentum and quasi - momentum in a periodic potential ; we also show that it is by far more useful to define the effective mass as a quantity relating the average carrier velocity to the quasi - Momentum.    important applications of the velocity mass are indicated. in addition, we briefly describe a " semi
the origin of the small neutrino mass is still a mystery.   it is commonly believed that neutrinos are a low - energy manifestation of physics beyond the standard model and that their smallness is due to a suppression generated by a new high - energy scale, perhaps related to the unification of forces. in this paper  , we have discussed the leptogenesis scenario by the decay of the lightest neutral component of fermion triplet and it s phenomenological implications which may be testable in near future. here   we give the first full calculation of thermal leptogenesis by the decays of @xmath6 triplet fermions under the seesaw mechanism using a three generation model of the same model ( @x Math8(2 ) fermionic triplet with y=1 ).. the kinematical effect of the leaptogenesis has been discussed and the scenario can alter the out - of equilibrium condition substantially. for the first time we have calculated the temperature dependence of the neutrinuclear mass of the two types of heavy particles through the decay process of the second generation of the fermium triplet@xmath0 and the role of dark matter
the day - night asymmetry of the observed solar neutrino flux in vacuum is one of the most important issues in the neutrinos oscillations framework.   the present analysis shows that the observed asymmetry is only a small fraction of the theoretically predicted one, which is separated from the experimentally predicted one by at least one order of magnitude. to find the exact solution of the matrix linear ordinary differential equation @xcite, the schroedinger - like equation is solved in terms of the flavor evolution matrix ( operator ) and the spinor representation @xmath2. the results are compared with the results of several other experiments, including the borexino collaboration's experiments, which have already reported the possible observation of the asymmetry at the level of @x Math1 for beryllium neutrines, however, with a high uncertainty.
the temperature and density distribution along some loop structures observed by high angular resolution ( 1 " ) x - ray imaging of the solar corona have been recently investigated by lenz et al. ( 1999, hereafter l99 ).   they have selected four relatively isolated loops extending above the solar limb and steady, at least for time intervals of 1 - 2 hr.although the filter ratio varies very little along the four loops, l99 find that the temperatures profiles are constant along the loops, around 1.3 mk. this finding is at variance from a static, steady - state, non - isothermal loop model, in which the temperature profile would be rather flat in the corona according to this model, and the observed profile is significantly ( and incompatibly ) flatter. here   we revisits this interpretation in light of a more realistic scenario where the loops detected by trace consist of bundles of filaments independent of each other, possibly in different physical conditions, and, in particular, at different temperatures. using a non - wasothermal model, we show that trace diagnostic may actually yield an apparently almost isothermal profile along most of a loop consisting of such a bundle. however, we conclude that the evidence of isothermal
the linear boltzmann transport ( lbt ) model is a powerful tool for the study of jet quenching in high - energy heavy - ion collisions.   it combines a kinetic description of parton propagation and hydrodynamic description of the underlying medium evolution. within the lbt model,   thermal recoil partons from each scattering and their further propagation in the medium are captured and used to modify both the jet transverse momentum broadening squared per unit length of propagation and the jet transport parameter at the center of central au+au and pb+pb collisions at the large hadron collider ( lhc ). here  , we present an analysis of the effects of these two parameters on the formation of jet - induced medium excitations such as supersonic waves and mach cones using the l BT model.. the results show that the observed suppression of single - hadron hadron spectra at large transverse energies is due to the dissipation of most of the energy lost to the medium by the propagating parton through multiple scattering and induced gluon bremsstrahlung, leading to a large fraction of the total jet energy being absorbed by the medium during each scattering.
the forest fire propagation model proposed here is a variant of the so called local small - world network model ( @xmath1 ).   it is a stochastic model which considers flame radiation as the mechanism of fuel preheating and spotting effect, thus including long - range interactions, well beyond the nearest neighbors. in this model,   the fire spread starting from the interaction between linked sites is accounted giving a phenomenological description of the interaction with neighboring sites ( trees ) in order to construct the whole spreading process.. this phenomenology is represented via a system of coupled first order differential equations for the normalized mass at each site. using a continuous fire spread model scheme instead of a discrete one, we focus our attention in the effect of the terrain slope in the spread of a forest fire.    we find that the slope of the topography has a significant effect on the rate of fire spread over time, but the effects of the other parameters are less important.
information cascades are common in online social networks.   they are created when an individual forwards an email she receives to her contacts or retweets a news item to her followers on twitter. understanding how information spreads through these cascades may help us identify patterns, trends, and anomalies within the cascades in near real - time. however, to the best of our knowledge, no previous work has attempted to quantify the dynamics of information cascades on social networks or characterize their microscopic growth. to address this gap, we propose a _ practical, general, and scalable quantitative framework _ for the analysis of cascades by using a cascade generating function, which captures the details of the dynamic properties of information diffusion on networks. with this function, we can compute the macroscopic properties of the cascade ( size, diameter, average path length, etc. ), reconstruct its shape, and analyze its microscopic dynamic properties. as the size of data sets grows, storing the complete structure may not be feasible, but the cascade Generating function can approximate the structure of the network with very high accuracy, in spite of having pseudo - linear space complexity. here  , we present a fast, efficient algorithm to compute this function and demonstrate its
hot jupiters frequently have radii which are inflated relative to the expected mass - radius relation.   models for this behavior include tidal heating ( gu et al. 2004 ) and " ohmic heating " due to interactions between atmospheric flows and the planetary magnetic field ( batygin et al. 2011 ). in this work   we explore the ramifications of that suggestion in the context of a more complete planetary model, which calculates currents internal to the planet generated by the electric potential difference produced by the stellar wind / magnetosphere interaction and mapped down to the outer layers of the planet, analogous to the " global electric circuit" ( gec ; ( *????   2007 ).    the proposed gec model is capable of heating the entire planetary interior, and produces planetary radii broadly in accord with observations.
the exact many - body energy eigensolutions of hard core, or impenetrable, point bosons in a harmonic trap are obtained using the fermi - bose mapping theorem for the tonks - gas limit.   the results are compared with the gross - pitaevskii approximation, which assumes that all @xmath2 bosons occupy the same orbital ( complete bose - einstein condensate, condensed fraction unity ) and that the occupation of the lowest orbital is of order. to test this assumption, we find that the absolute number of atoms in the trap is much smaller than the number of atom(s ) assumed by the gross-pitaevskii approximation, and the maximum eigenvalue of the macroscopic orbital is larger than that of the off - diagonal long - range order ( odlro ) orbital. however, the density of the single - particle density is not significantly different between the two approximations, and it is found that the spatial interference fringes of the separated and recombined condensates are much weaker than those predicted by the corresponding time - dependent mean field theory.
we investigate the transport properties of @xcite quantum dots in terms of the eigenvalues of the scattering matrix which determine the conductance and shot noise power.   we find that the joint probability density of transmission eigen values, which determine all stationary transport properties, for an arbitrary number of open channels supported by the leads attached to the quantum dot, turns out to take a particularly simple form with no non trivial dependence of the ensemble - averaged conductance or shot noise on the number ofopen transport channels.    our theory also explains the deviations from standard random - matrix theory observed in earlier numerical investigations.
the integrated energy spectrum of primary, relativistic electrons in a cluster of galaxies is presented.   the model is based on the assumption that the electrons remain trapped in the cluster and that they do not lose energy by inverse compton ( ic ) scattering of the cosmic microwave background ( cmb ) photons. for the same number of electrons with energies in the range @xmath8 to@xmath22, the total rate of production of new cosmic rays in this energy range is @x Math24 + q ( \gamma \   \, \ ] where @xMath24 is the number of particles in the galaxy with energies from ~0.1 to ~2.0 gev. under the same assumptions,   gamma - ray emission by the same electrons ( as well as emission by ions through decay ) will also be discussed.
the x - ray free electron laser ( xfel ) is a new generation of synchrotron radiation ( sr ) source that can deliver high quality x - rays and xuv light in the coherent regime.   the last generation of sr sources  the xfels  have reached the record gw powers for the ngstrm wavelengths, but the level of collimation and monoenergeticity required for the x -ray amplification yet remains challenging. in our work   we tackle this problem considering a scheme based on a specific configuration of the optical undulator  the optical lattice which results from the overlap of two identical side laser beams and represents a spatially, transversally modulated electromagnetic field structure. by using the electron slow motion in the lattice as a low frequency light source, we show that the rate of coherent amplification of the incoherent undulator radiation produced by the laser accelerated electrons can be effectively enhanced to the gev level with the help of the laser plasma accelerator ( lpa ) providing the necessary high electron flux.
the generic matrix - matrix multiplication ( gemm ) kernel is arguably the most popular computational kernel of the 20th century.   its apparent simplicity has haunted generation after generation of researchers who have evaluated its performance, while uncovering layer after layer of its hidden complexity. yet, no common methodology for evaluating gemm performance has been established over the many decades of using this kernel for comparing architectures, compilers and ninja - class programmers. here  , we introduce gemmbench, a framework and methodology for evaluation performance of gemm implementations. in addition to providing a framework for testing the performance of hand - written opencl kernels operating on various data types and data sizes,   it also provides a set of tests that can be used to compare gemm generators across different architectures, data types, data sizes and data types.. the framework is implemented on top of collective knowledge, a lightweight framework for reproducible and collaborative r&d in computer systems.
laser frequency stabilization is an essential requirement for various applications including atom cooling, high resolution spectroscopy, precision measurements@xcite etc.   the most commonly used technique for frequency locking involves locking to the side of the doppler free peak generated from the saturated absorption spectra ( sas ) @xcite. here, we present a technique which generates a narrow tunable dichroic lock ( dfdl ) signal using circular dichroism of an atomic vapour in the presence of a magnetic field and its frequency tuning is achieved by varying the pump laser frequency using automolecular energy modulators ( aoms ). at the same time, the locking performance of an extended cavity diode laser ( ecdl ) system is investigated by measuring change in the number of cold atoms in a magneto - optical trap ( mot ) using the locked tdfdl signal. as a result, it is found that the locking efficiency of the ecdl system is improved with increasing the pump beam power and the magnetic field.
the possibility of variation of the fine structure constant @xmath5 is predicted by theories unifying gravity with other interactions.   recent progress in improving atomic clocks and developing optical frequency standards has made it possible to put strong constrains on possible time variation of fundamental constants in laboratory measurements. however, the choice of atomic transitions used so far was not optimal for searching of variations of thefine structure constant. here   we suggest to study anomalously small fine structure intervals in ground configurations of many - electron atoms using the ground state fine structure multiplet which ensures that states are metastable. a number of such transitions were suggested in recent work   @xcite. in present work we consider slightly different possibility.we show that the use of these transitions can be used to study sensitivity of atomic frequencies to variation of@x Math5-variation as well as to find out whether they are consistent with the quasar absorption spectra data if the same rate of change is assumed over cosmological time.
photo - induced two - nucleon emission reactions are generally considered as a valuable tool for the investigation of the two - body aspects of nuclear structure @xcite.   the main contribution to the strength of the ( @xmath1,pn ) reaction is supposed to come from the pion exchange currents. in this work   we have used the gottfried approach to calculate the angular cross section of the direct knockout reaction mechanism after photoabsorption using a model in which the nuclear structure effects are clearly separated from the physics of the photo absorption. under the most transparant conditions  , we show that the cross section can be estimated by taking into account the interaction between the outgoing particles and the residual nucleus.. the influence of heavier meson exchange on the cross sections is investigated.    the results show that it is possible to obtain a good approximation of the total cross section in the range of 0.5 to 1.0 ev.
topological properties for objects in 2d and 3d space is an important task in image processing.   this paper provides a complete process that deals with simulated and real data in order to obtain the topological invariants for two - dimensional ( 2d ) and three -dimensional ( 3d ) images using digital topology as a framework.    the algorithms are : ( 1 ) 2d hole counting, and ( 2 ) 3d boundary surface genus calculation.. the first algorithm is based on the concept of adjacency and connectedness of ( unit ) cells, and the second algorithm uses the term genus to represent the boundary surface of a 3d object. both algorithms are suitable for 2d holes counting and border surface genus calculations., the latter algorithm is particularly useful for detecting noise or pathological cases in real images.
photoassociation of ultracold atoms @xcite with resonantly enhanced anti - stokes raman ( rear ) pulses in counter - intuitive ordering is an attractive idea, mainly due to the promise of high yield.   this paper describes a set of realistic calculations of the @xmath0rb+@x Math0rb@xmath8 @x math0rb=0.1 + 1 at 100 k temperature, employing the laser pulses that photoassociate most initial states in the thermal ensemble. by applying the coherent pulses over and over on the thermal ensembles of colliding atoms,   the overall photoass association yield can approach unity on a reasonable time scale.
we study the phenomenology of supersymmetry susy breaking terms in models where the action is dominated by one loop order contributions to soft breaking terms.   we focus on models in which string nonperturbative corrections to the kahler potential act to stabilize the dilaton in the presence of gaugino condensation @xcite, and show that these models show new behavior that interpolates between the phenomenological of unified supergravity models ( msugra ) and models dominated by the superconformal anomalies ( amsb ). this interplay between universality and non  universality gives a rich new phenomenology, and indicates new trends in the search for supersymmetric particles in accelerator or astroparticle physics.
linear and circular polarization are important diagnostics of synchrotron sources. in active galactic nuclei and galactic microquasars, polarization is useful for characterizing particle energy, magnetic field configuration and jet composition @xcite.   variability in polarization is important for diagnosing shocks and the stability of accretion processes. here   we present new observations of linear and circular polarized emission in sagittarius a *, the compact nonthermal radio source in the galactic center. at 230 ghz ( 1.3 mm wavelength )  , the emission shows no linear polarization between 1.4 and 112 ghz at limits of 0.1 to 2% @xmath6. however, surprisingly, the emissions are circularly polarized up to 43 ghz. these observations complement past work that has shown a complex picture of the polarization in sgr a*. the apparent sharp transition in linear polarization apparent between 112 and 150 ghz from these observations is very unusual and has important implications for the source physics.
the effects of neutrino trapping on the equation of state ( eos ) of a newly born neutron star or proto - neutron star ( pns ) at zero temperature are investigated by using the brueckner - hartree - fock approach.   the results show that the eos of the trapped matter is significantly stiffer than that of the non - trapped matter, and that the baryon density of the stellar matter is sensitively dependent on the nuclear symmetry energy and the presence of kaons. in the present work, the influence of tbfs on the structure and composition of the proton fraction of the supernatant of the hot neutrinos - trapped star is investigated within the context of the model for kaon - nucleon interaction based on the walecka model. to explore the interplay between the roles played by these two factors, we investigate the effect of finite temperature on the internal composition of protoneutron stars, and their evolution. as a consequence, the maximum mass and the corresponding radius of the star are found to be much lower than the theoretical predictions.
the present paper is a sequel of a previous work concerning the evaluation of saddle - point integrals of the form @xmath0\,\mathrm{d}s, \label{sd.1}\ ] where@xmath1 is a suitable integration path in the complex @x maths2-plane, @x math3 and @x Math4 are functions which, for simplicity, will be assumed to be nonsingular, and @Xmath5 will be intended as a " large " ( in modulus ) complex parameter.   the marriage between hyperasymptotics@xcite and the weniger transformation @xcite, generating the so - called h - wt, allows the wt to successfully operate also across stokes sets. here  , we show how the 1st - order h -wt, for which only the first - stage of h is anticipated to the wn, is able to provide relative errors several orders of magnitude smaller than those achievable via the use of full hyperasy mptotic treatments and with considerably lighter computational complexity and effort. on the other hand, on increasing the order of h, the number of asymptotic series associated to
the spectroscopy of plasma evolution from astrophysical radiation ( spear / fims ), also known as far - ultraviolet imaging spectrograph, carried out the global observation of the cygnus loop in two wavelength channels, 9001150  and 13401750 .   @xcite reported the early results using only the long wavelength channel data. in this paper, we present the new images of the entire region of the Cygnus Loop using the short wavelength channel datasets of the spear /fims observations and compare them with the previously reported results. for the emission lines originating from non - radiative or radiative shocks,   the new image at @xmath01486 is also presented with the newly processed spear/fims data. to understand the spectrum properties of the outer rim of the shell, we separate out the blended + image, which was originally presented in@xcite, into two individual images of and. a new imageat @x Math01486 has been created by combining the combined images of both the former and the latter.the resulting images are compared with the x - ray, optical, and 21 cm images and show that the intensity of the line ratio of to is much higher
we trace the time dependence of the h@xmath1 gas content of the galaxy - galaxy merger sequence in light - infrared galaxies ( ligs ) by measuring the co(1 - 0 ) luminosity as a function of the merger separation.   we use a heterogeneous sample of 50 ligs with @xmath6, 19 of which are ultra - ligs ( uligs ) and most are merging / interacting molecular gas rich with a high star formation ( sf ) rate. using sub - arcsec imaging, we identify the 2 progenitors from ccd images usually in the red or near - ir and measure the cosmological characteristics of the newly formed galaxies. for all ligs,   the mean distance between the merging nuclei of the merging galaxies is ~2.5  km and the mean diameter of the merged system is ~3.0  cm.    we find that the first stage of the merge is the most likely to start with a relatively large supply of h@X-1 gas, which is responsible for the sf. at the same time, the second stage is the least likely to begin with a very small supply of this gas, but the third
heavy quarkonia are an excellent tool to study the modifications of the basic qcd force in hot / dense matter.   the simultaneous study of charmonium and bottomonium observables in ultra - relativistic heavy - ion collisions ( urhics ) is particularly valuable, since the differences in binding energies and reaction rates between them enable a much improved discrimination power of bound - state suppression and regeneration mechanisms. here   we present a theoretical framework to properly interpret experimental data in urhic experiments, which is based on a kinetic - rate equation approach that accounts for the off - equilibrium nature of quarkonium formation and dissociation reactions in a locally equilibrated, yet evolving medium, as well as off - balance aspects in initial conditions and in heavy - quark ( hq ) kinetics. using this framework, we have investigated the effects of low - energy interactions between pb - pb and au - au collisions at top sps ( @xmath12=17.3agev and rhic=200 agev ) on the formation of both charmonia ( psi ) and bottomons ( ups ),
a successful hydrodynamic theory of granular media could allow scientists and engineers to exploit the powerful techniques of fluid dynamics to describe granular phenomena.   we use three - dimensional ( 3d ) simulations of continuum equations to navier - stokes order and 3d inelastic hard - sphere molecular dynamics ( md ) simulations to investigate the onset of ordered standing wave patterns in vertically oscillated granular layers. using a continuum model for frictionless, inelastically particles, we find that the formation of standing waves is dependent on the frequency of plate oscillation and the velocity of the layer at rest. by simulating an impenetrable plate oscillating sinusoidally in the direction of gravity, we show that stripes form in the layer with respect to the plate as a function of the speed of plate motion, and that these patterns are subharmonic depending on the magnitude of the acceleration due to gravity and the number of grains on the plate..graphical abstract
the arecibo   hi strip survey is an unbiased 21 cm survey of galaxies with very low surface density.   the survey yielded a total of 61 detections, of which about half could be associated with cataloged galaxies listed in the nasa extragalactic database ( ned ) and about five detections with galactic latitude @xmath6 have no obvious counterparts on the digitized sky survey ( dss ). using short ( 20 min ) 21 cm line observations of 55 of the 61 detected galaxies with the vla during the d - configuration session in may 1995, we have constructed hi maps and global profiles of 52 of the 55 potential galaxies. by using optical follow up observations carried out on the 2.5 m isaac newton telescope on la palma in october 1995 and february 1996,   we have been able to make optical identifications of all high surface brightness ( hi ) selected galaxies. among the hi selected galaxies, only two have been found to have isolated high surface bright intergalactic hi clouds without stars. from the results of these observations, we conclude that there is no substantial population of low surface brightness galaxies that has been missed optically.
we propose a biomimetic design of an interacting effective spin system as a working medium for a synthetic quantum coherent heat engine.   we examine an extreme but naturally occuring case in light harvesting complexes where only few spins in the large ensemble can be excited by a bosonic field of spin waves and describe the interaction of the spin ensemble with the central spin as a spin - boson form known as rabi model. implementing the natural strategy of light harvesting complex indirectly with a continuum of quantum huygen s clocks  , we propose a scheme where large number of spins are homogeneously coupled to a central spin, which could build a global quantum coherence.
we introduce a new model for the decay of the pion decays in deep inelastic processes.   the model is based on a scalar vacuum - like field @xmath5 intended to represent globally the fluctuations of the quark - gluonic field which can not be described in terms of a few elementary excitations and includes a few nonperturbative effects which are essential in the description of the binding and of the generation of new particles. by means of the time translation operators, we describe the modifications produced in the structure of the free hadronic states by an external interaction. as a result  , we derive the expression of the partial width of the weak radiative decay and the inadvertencies found by us here.
sagittarius a * ( sgr  a * ) is a compact radio and infrared source located in the vicinity of the super - massive black hole ( smbh ) at the center of the milky way.   the observations of the variable polarized nir emission and simultaneous radio / nir / x - ray observations of sgra * are ideally suited to obtain deep insights into the relativistic physics within 10 - 100 schwarzschild radii of the smbh associated with sgra*. here   we present a new model of the accretion of stellar winds onto sgr a * based on the observed nir flare variability and highly polarized emission, which can be explained by a synchrotron self - compton model involving up - scattered sub - millimeter photons from a compact source component as well as the inverse compton scattering of the thz - peaked flare spectrum by the relatival electrons. for the first time  , we show that the nir flares can be fully explained by an adiabatic expansion model using a combination of two different mechanisms : ( 1 ) the rapid rate of accretion flow and jet models and ( 2 ) the low radiation efficiency of the current acc
alpha particle structures @xcite could be present in atomic nuclei.   the main idea of the present approach is to verify whether these subtle changes, in case of @xmath6-alpha nuclei, could be attributed to the appearance of alpha - like clusters which modify the structure of the wave function and introduce strong correlations between nucleons.    the model predictions for the binding energies, root mean square ( rms ) radii and density profiles as a function of the number of alpha particles in the @x Math6-beta nuclei are compared with the experimentally determined values. it is shown that the hypothesis of alpha structures can indeed describe the binding energy systematics of bethe@xcite.the experimental data show that the rms radii increase with increasing number of beta particles in both the ground state and the subsaturation densities of the nuclear matter. at the sub - subsaturation density,   most of the differences between the experimental and the model results are explained by the presence of alpha particle clusters in the wave functions of the waves.
the anticoincidence shield of spi ( spi - acs ) is an omnidirectional gamma - ray burst detector aboard the integral mission.   it provides a large effective area for the detection of cosmic gamma -ray bursts ( grbs ) and produces time profiles with a resolution of 50ms. since december 2002  , it has been an important member of the 3@xmath7 interplanetary network of @xmath8-ray burst detectors, which provides burst localizations using the triangulation method. by studying triangulations of bursts with accurately known positions such as soft - gamma - rays repeaters and grbs with counterpart detections,   the absolute timing uncertainty was estimated to be of the order of 100ms. in this article   we present a systematic timing inaccuracy study of some bursts with precisely known localizations performed using the konus - wind and/or helicon - coronas - f instruments in conjunction with spi / utc data from the integra mission. at the same time, we discuss the current state of the art in the detection and investigation of grbs.
the fundamental theory of strong interactions, quantum chromodynamics ( qcd ), possesses an exact local gauge symmetry and an approximate global symmetry for massless quark flavours.   the chiral symmetry is the most important one, because it determines hadronic interactions in the low - energy region. in the linear representation of the symmetry, the so - called linear sigma model,   both the scalar and pseudoscalar degrees of freedom are present. here   we study an @xmath23 linear s Sigma model which contains scalar ( @x math3, @x Math24 ) and pseudo - calcaricar (@xmath25, @Xmath26 ), and in addition also vector ( ~0.5 kcal / mol ) and axial - vector (~0.1 kcal /mol ) degrees offreedom. within such a model, we show that the classical chiral symmetries of qcd are broken in two ways : explicitly by quantum effects and spontaneously by the non - vanishing expectation value of the quark condensate. due to the explicit breaking of the x - ray symmetry at sufficiently low temperatures and densities, the pion - pion scattering lengths
we introduce an alternate design for an exchange gate in a two - qubit donor system, which allows flexibility in device fabrication and in tuning the exchange coupling.   this new design can 1 ) eliminate the need for additional j - gates between the donors, 2 ) function with a range of donor separations, 3 ) provide a 5 order of magnitude j - tunability within a modest e - field range of @xmath23 mv / m2 and lowered off state exchange, and 4 ) mitigate the j - oscillations with donor separation. to perform these state - of - the - art calculations of exchange energy in donor qubits, we have combined atomistic full band electronic structure calculations, electrostatic device simulations, and a two electron full configuration interaction ( fci ) technique over a lattice of 1.7 million atoms. by studying double quantum dots ( dqd ) based on donor clusters in silicon @xcite, we find that an asymmetric 2p-1p system outperforms the symmetric 1p-onep system in exchange controllability with detuning gates. as the electron bound to one donor   is pulled to the other by the electric field, the exchange couplings can
we have used the formalism of statistical mechanics to analyse the observed peculiar velocity distribution function of galaxies in the expanding universe.   the results show that the distribution of galaxies is very close to quasi - equilibrium in both its linear and nonlinear regimes, and this holds for both the general partition function and the general many - body problem for a system of two different kind of galaxies. using the newton s law, it has been shown that the effect of dark energy in the form of cosmological constant on the partition function of galaxy can be introduced as an additional correction term in this partition function. also, the effects of uncertainties in sampling on the estimated distribution function have been studied.
we explore the connection between dynamics, characterization of structure as contained in the pair and higher order correlations, and entropy, and relations between them as described by mode coupling theory ( mct ) and the adam - gibbs ( ag ) relation using computer simulations of two model liquids with different interaction potentials.   we find that the slow dynamics of the lennard - jones ( lj ) system is due to a large difference in the point - to - set correlation length of the two body radial distribution function ( rdf ) between the two systems. at low temperatures,   the ag relation is found to hold for a wide range of systems below a moderately high temperature referred to as the onset temperature of slow dynamics where the configurational entropy of the system is lower than the pair entropy obtained from the pair correlation function. on the other hand, the mct divergence temperature at which an approximation to the Configurational Entropy using pair correlation alone goes to zero is similar to the transition temperature of the slower dynamics. under certain approximations of the modes coupling theory divergence temperature, the diffusion coefficient as obtained from mct follows rosenfeld scaling, whereas under certain conditions the transport coefficients follow the Adam - gib
the most widely accepted mechanism for the formation of planets is the core accretion model.   this model assumes that dust grains grow rapidly to form kilometre - sized planetesimals that coagulate to form a rocky core, which, if sufficiently massive, may then accrete a gaseous envelope to from a gas giant planet. in this work   we expand on this model by considering how a population of planetary - mass bodies forming beyond @xmath4 au would evolve through dynamical interactions with an outer population of stellar companions, that drive kozai - lidov oscillations, and then through tidal interactions with the host star. using the equations that describe the secular evolution of a star - planet - star system, first presented by @xcite, we show that the orbital properties of planets that originated at large radii are similar to those of the known exoplanet population, and that these planets could have originated with large initial semi - major axes (@xmath1 au ) and that have then been scattered onto orbits with semi - minor axes inside @x Math2 myr. however, our results suggest that some of these planets may have formed via disc fragmentation, with others having evolved through tidal
the finite temperature green s function formalism is employed to study low - energy effective models, such as the hubbard   @xcite model, either by numerical or analytical means.   however, the eigenvalue spread of realistic hamiltonians is very broad ; thus, the finite temperature Green s function formallyism, when applied to realistic problems, has to describe energy levels far outside the window described by model hamiltonian. in practical calculations,   temperature - dependent green s functions are expressed as functions of imaginary time or imaginary frequency that are mutually connected by a fourier transform. since realistic ham Miltonians have a wide spread of orbital energies, both grid points need to contain hundreds of thousands of grid points to reach high numerical accuracy at low temperatures that result in small grid spacing. for accurate and affordable realistic calculations, it is highly desirable to find compact representations of both imaginary time and matsubaragreen s functions. in this paper  , we focus on finding a representation that will result in using compact matrices for realistic systems.
dv psc is a rs cvn - type eclipsing binary with high - level surface activity, which is characterized by the light - cuvre asymmetries and @xmath1 h&k emission.   our new ccd photometric observations of dv pocs were made in four observing runs : 2010 nov. 19, 20, and 2011 oct. 12 and 13, dec. 08 and 10 with 85 cm telescope at xinglong station of the national astronomical observatories of china (@xmath2 ).. the spectroscopic observations of this binary were obtained with the 2.16 m telescope at zinglong Station of the niho national center for optical astronomy ( ncao ) on 2012 feb. to july 2012 using the omr spectrograph centered at about 4280 @x Math3 with a reciprocal dispersion of 1.03 @x math3.    the normalized spectra of dvspsc were analyzed with the spectral subtraction technique. an updated linear ephemeris formula min.i =  jd(hel.)2454026.1424(2 ) + 0.30853609(8)
the planck scale is a fundamental length / energy scale where the smooth manifold model of spacetime breaks down.   the very concept of distance becomes physically meaningless at this scale and spacetime " evaporates" into something different, a sort of " foamy" structure, a spin network, a fractal dust, _ etc. according with the chosen model. in this regard  , one of the most powerful frameworks for describing the planckian phase of gravity is definitely ( super)string theory. however, it is important to remark that while the compton wavelength of a particle - type excitation decreases by increasing the mass, the schwarzschild radius of a black hole increases with its mass. as there does not exist any physical object smaller than a string, there is no physical ways to probe distances smaller than the length of the string itself. in order to overcome this limitation,   noncommutative geometry inspired solutions of the einstein equations have been proposed which are based on the existence of a lower bound for the mass and size of black holes. here   we review the current state of the art in the field of quantum gravity using the recently proposed ultraviolet self - complete scenario @xcite.
hawking radiation from black holes is one of the most striking effects that is known, or at least widely agreed to arise from combination of quantum mechanics and general relativity. in this paper, a reissner - nordstrm black hole surrounded by quintessence is considered to investigate quasinormal frequencies ( qnms ) and hawking radiations including the influence of the quintessences on them.   the qn frequencies of the scalar perturbation are evaluated by using the third order wkb approximation method. in the case of the complex scalar field, we consider the evolution of massless oscillations in the background using the tortoise coordinate defined by @xmath14 and the normalization factor related to the density of quartessence defined by@xmath15.    the results show that the rate of the decay of the charged scalar hair is faster in the context of the presence of quintessent matter than in the absence of it. also, the frequency of the Hawking radiation in the reisser - nortstrm background is significantly higher than that in the universe without quintessension.
barred spiral galaxies are ideal laboratories for the study of star formation because they host a variety of environments with distinctive star formation activity and gas dynamics.   most previous studies comparing the distribution of molecular gas and star formation in barred spirals have focused on the highly active circumnuclear region ( e.g., @xcite ). in this paper  , we focus on the unique region between the bar ends and the nucleus, which is dominated by highly elliptical stellar orbits. using the co ( j=1 - 0 ) emission line to trace the molecular gas, and the ionized hydrogen ( h@xmath0  ) lines to trace recent star formation activities, we compare the relative distribution of the two in six barred spiral samples from the recently completed bima survey of nearby galaxies ( song ). using one and two dimensional cross - correlation analysis, we find that the majority of the h@Xmath0 emission is offset towards the leading side of the moleculargas.    the co - h@ xmath0 offset constrains how stars may form depending on the gas flow into the dust lane.,we discuss the results of the cross - correlations analysis in the framework of the n - body
the theory of particle acceleration at shock fronts moving with arbitrary speeds ( from newtonian to ultra - relativistic ) can be formulated in a simple and exact form @xcite, which neglects the dynamical reaction of accelerated particles on the shock. in this framework,   all the basic physical ingredients can be taken into account in an exact way, with special reference to the type of scattering that is responsible for the particles to return to the shock front from the upstream and downstream plasmas.   the mathematical method adopted to calculate the two very important functions @xmath7 and@xmath8 based upon the knowledge of the elementary scattering function @x math3 was described in detail in @xcitesite. in these papers we extend the application of this new theoretical framework to two new interesting situations : 1 ) presence of a coherent large scale magnetic field in the upstream fluid ; 2 ) anisotropic scattering. in both cases   we calculate the spectrum of accelerateable particles and the distribution in pitch angle for shock fronts Moving with arbitrary velocity for non relativism and for relativistically shocks, and assuming small as well as large pitch angle isotropic scattering.the results of point 1 are compared
the archives of high - value observational data ( e.g., nasa s hsearc ) have been a great boon to astronomical research in the past decade.   it has given rise to a new kind of astronomer  the archival astronomer  who is free to check the methods and results of the authors of the data s authors, as well as to pursue independent, and sometimes novel, lines of inquiry. by creating this archive of simulated x - ray clusters, we hope to extend this concept into the computational realm where simulations are growing in size and complexity. here   we present the sca ( http://www.ncsa.nasa.gov/sca/ ), a web server for the analysis of archived experimental data at high resolution using a new hydro+n - body code @xcite which uses adaptive mesh refinement to place high resolution grids where needed. with the help of these grid methods, we have created large, statistical catalogs of @xmath1 100 clusters simulated at high spatial and mass resolution for two cases : ( 1 ) with, and ( 2 ) without non - adiabatic physical processes in order to understand the role of non - adsorption in x
we show that the distribution of all base stations of all operators in the paris area can be fitted with a poisson point process ( ppp ).   we prove that the superposition of different ginibre point processes ( @xmath0-gpps ) converges in distribution to a ppp process and draw conclusions on the coverage - capacity trade - offs made by different operators. qualitative results are derived from the inferred values of @x Math0 and the intensity @x math2..@xmath2 can give information on the dimensioning strategy adopted by the operator, while @x maths0 give insights on the network coverage.
relativistic heavy - ion collisions present a unique possibility to create nuclear matter at high densities and temperatures where the hadron properties become different and a phase transition to quark matter with signatures of the deconfinement and restoration of chiral symmetry is expected.   the dilepton spectra from the dls collaboration at bevalac @xcite show that the production of dileptons with invariant masses between @xmath19 mev is found to be enhanced as compared to estimates based on the theoretically known dilepton sources when in - medium modifications ofHadron properties are neglected.
the generalized chaplygin gas ( gcg ) is an effective description of a coupled fluid composed by dark energy with equation of state given by @xmath5 and a cold dark matter with a dynamical mass driven by the scalar field.   it is shown that the cosmological evolution of the composed fluid is governed by the same dynamics prescribed by cosmon field equations, which suggests that the mass varying mechanism embedded into the cosmon-_like _ dynamics reproduces the effective behaviour of the gcG.. in addition, coupling dark matter to dark energy by means of a dynamically mass driven scalar fields allows for reproducing the conditions for the present cosmic acceleration and for recovering the stability prescribed by a positive squared speed of sound.
we report the existence of a peculiar degassing regime in a thin layer of micellar fluid ( ctab / nasal mixture ).   when a constant air flow is imposed at its bottom, in the bubbling regime, the air is released through periodic series of successive bubbles, hereafter named'cascades'.'in this article, we extend these previous works to the case of a fluid without yield stress, and for a _ thin _ fluid layer, i.e., when the fluid height is smaller than the typical size of a bubble. inside a cascade,   the bubble properties vary continuously : the mean overpressure drops, whereas the emission time increases ; the transition between two regimes inside the cascades is directly linked to the fluid rheology and, in particular, to the viscoelastic characteristic time associated with the maxwell fluid.
the ` single source model'of the formation of the knee in the cosmic ray energy spectrum at @xmath03 pev @xcite is based on the assumption that a single, relatively recent and nearby supernova remnant contributes significantly to the intensity at pev energies.   recently, thorsett et al. found the distance of the pulsar psr 0656 + 14 associated with the snr monogem ring and its spin - down age is 288@xmath130 pc and it is likely to be the single source responsible for the sharpness of the peak in the energy spectrum of cosmic rays at ~0.25 pv, which is the maximum rigidity of the particles emitted by the pulsars at the present time. in this paper   we analyse the possibility of the pulse psr b0656 +14 being the single sources responsible for these observations and also see to what extent the eas excess (  the armenian peak') could come from the same object.
geometric phase is a concept of central importance in quantum physics.   uhlmann was the first to consider the notion of geometric phase for mixed quantum states, using his elegant and generally applicable " purification theory " @xcite. more recently, sjqvist   - tong _ et al. have derived a geometric phase which differs from that of uhlman s, but which reproduces the geometric phase of sjquistist - tong   ( 2013 ). in this paper   we conduct a detailed geometric analysis of Uhlmann s standard purification bundle using tools from the theory of dynamical systems with symmetries, and we derive a new connection for this bundle which gives rise to sjgren - tong's geometric phase.
the advection dominated accretion flows ( adafs ) are quasi - spherical gas flows with optically thin inner regions.   they are characterized by their quasi - sphericity, high temperature and low rate of accretion. in this paper   we investigate the radiation processes and spectra emitted by these flows in the kerr spacetime using a fully self - consistent, relativistic description of the radiation from the advective flows. for a simple equation of state of the flow,   the profile of the angular momentum, radial velocity of matter and the speed of sound depends only on the viscosity parameter @xmath0 and the values of the specific angular momentum and energy of matter at the horizon. to get rough solutions of the hydrodynamic equations we use an approximate treatment, neglecting the cooling.    the most time consuming part of the calculations is decoupled from the equations of motion. because of the low radiation efficiency, the flow can heat up to near virial temperatures and the pressure gradients play an important role in the gas dynamics, we consider the effects of ray deflection, doppler shifts and gravitational redshift on the behavior of the adsorbed matter
social networks is an approach for representing relations between individuals, groups or organization.   the concept of social networks extraction is designed to map the relationship of entities among them that can be observed, to mark the patterns of ties between social actors, to measure the social capital : the values obtained by the entities individually or in groups, to present a variety of social structures according to the interests and its implementation, based on different domains or information sources, such as the web documents. in this paper, we present a new method for extracting social networks from web documents by involving the superficial strategy that depends heavily on the co - occurrence, i.e., the singleton and doubleton event. using the similarity measure, we show that the extracted social networks are more similar to each other than to the existing unsupervised method, which utilizes the cartesian product for clustering the nodes in the network. however, the classification approach only concern with extraction of network based on predefined labels only, and thus can not be adapted to the other descriptions of relations. therefore, our goal is to enhance the superficial approach, an approach belong to unsuper supervised method, for extracting Social Network from web by not only relying on the Co - occurrence
we report results of a search for small - scale anisotropy in the arrival directions of ultrahigh energy cosmic rays observed by the high resolution fly s eye ( hires ) stereo detector between 1999 december and 2004 january.   we find no evidence of clustering in the arrived directions of cosmic rays at energies above @xmath5ev. to test the claim that clustering is a feature of cosmic ray arrival directions with independent experimental data, we present a new analysis of the air shower data from the hires stereo experiment. using a global minimization of the shower geometry, we show that there is no significant clustering of arrival directions at energies higher than @x Math2ev.the results are consistent with models in which ultrahigh power cosmic ray sources are distributed at large distances from our galaxy.
merged electron - ion beams arrangements at heavy - ion storage - rings equipped with electron coolers have evolved into powerful spectroscopic tools for studies of highly charged ions.   the experiments combine high detection efficiencies associated with fast moving ion beams with cold electron and ion beams. especially resonant electron -ion recombination, also termed dielectronic recombination ( dr ), provides access to the electronic structure of highlycharged ions over a wide range of energies from below 1 mev up to several 10 kev where the k - shells of the heaviest ions can be excited. in this paper   we review the most recent experimental electron - atom recombination work with an emphasis on the spectroscopy of highly charge ions.
the percolation model of nuclear fragmentation is a phenomenological model that can be used to calculate the fragment distribution observed in heavy ion collisions.   the model is based on the lattice gas model @xcite, which is a well - known model of liquid - gas phase transition in nuclei. here   we present a new version of the model that takes into account the thermodynamic properties of the system and includes the percolating process. for an @xmath8-particle system the canonical partition function of an excited state is written in a separable form : the number of nucleons in the system is the sum of the total number of atoms in the atom and the amount of time spent in the region of maximum energy where the system reaches thermal equilibrium. at some incident energies excited matter that is formed in collisions of two heavy ions   will pass through a liquid -gas phase transition stage. if fragments are formed at this stage, it may show characteristics of this phase transition.
markov chain monte carlo ( mcmc ) methods are very general tools in regard to dealing with intractable probabilistic settings.   one of these broad applications deals with the model selection problem where one tries to choose a model among many competing models that is more likely to have generated the given probability density @xcite. in this paper   we investigate a related problem in which the model that generates the given data is fixed, but accepts a random input with an unknown probability density function ( pdf ). if the target pdf of the distribution does not exist or can not be computed analytically then the question arises : how does one choose @xmath3 for @x Math4 to have the desired probability density@xmath5?   the answer to this question is not straightforward because the distributions of two or more input distributions can generate the desired output distribution creating an issue of non - uniqueness.    we propose a method to sample from the space of solution paths to a stochastic differential equation by using a markov chains montecarlo method.. the method is based on the inverse mapping of the variance of a random vector random variable into a set of random variables and
the molecular fraction, the ratio of molecular - gas density to the total gas density, in the gas disk of spiral galaxies is spatially correlated with the azimuthal angle of the galaxy s spiral arms.   we investigate the molecular front ( mf ) phenomenon across spiral arms by obtaining a two - dimensional distribution of molecular fraction in a galactic disk. using the ` grand - design'spiral galaxy ngc 5194 ( m51 ) as a model system, we construct a 2d map of the molecular fraction and apply the transition model established by elmegreen ( 1993 ) to the data from the literature, and compare it with the observed observations. for the simulations, we use the phase transition theory of elme green, and find that the molecular fractions in the radial direction are very similar to the observed data. at the same time, the molecular dynamics of the hi-  phase transition and molecular gas formation in the spiral arms are different from those in the interstellar matter.
the f2ia supergiant hd172481 is a candidate post - agb star because of its far infrared excess and its high galactic latitude.   the binary nature of this star was confirmed by its * spectral energy distribution * ( sed ), which is a mixture of two spectral types : atomic lines induced by a hot component ( @xmath57250k ) and tio bands caused by a cool component (@xmath53500k ) in the red region of the spectra. since the pulsational amplitude is very low, we conclude that these bands are caused by either a cool m - type companion or a hot hot component with a luminosity ratio of about 1.8.
a fully self - consistent non - relativistic equation of state ( eos ) for the hartree - fock approximation @xcite in three dimensions is calculated for the density and temperature regions of interest in the ` pasta'phase of stellar matter.   the model is based on the assumption of spherical symmetry and treats the matter as an ensemble of nucleons that naturally configures to a distribution corresponding to the minimal energy per particle at given density and temperatures. with the exception of the presence of chemical equilibrium at supernuclear densities, which is required for the use of this model in core - collapse supernova models, the eos can be used to calculate the pressure of a system as a function of density and heat in the whole density range of ~4@xmath010@x Math1 to ~20.1 @xmath3 from the subnuclear density of about 4 to the high density phase of ~0.61.0 @x math3 between the surface of the neutron star and the center of the neutron.
we present images and radial profiles in h@xmath0 and r for 29 isolated spiral galaxies.   the galaxy samples were selected based on their hubble type as well as local galaxy density, and we observed roughly equal numbers of different spiral types, with luminosities, distances, and inclinations as similar as possible to those of virgo spirals. because we wished to compare virgo and isolated spirals as a function ofHubble type classification, we selected our sample based on hubbletype as well at least in part by comparing the star formation properties of nearly 100 bright isolated and virgo cluster spiral galaxies via broadband r and h@Xmath0 images.
pulsar timing observations provide a unique opportunity to study low - frequency gravitational waves ( gws ) from supermassive black - hole ( smbh ) binary systems.   we show that existing pulsar data sets do not provide stringent constraints on the coalescence rate of smbh binary systems, but future data sets from the parkes pulsar timing array ( ppta ) and similar north american and european timing array projects aim to produce data sets on 20 or more pulsars with root - mean - square ( rms ) timing residuals close to 100ns. in the longer term  , we expect that many hundreds of pulsars will be able to time with exquisite timing precision. using two different techniques, one valid when there is a large number of expected sources and the other valid when only a few sources are expected, we show the recent and projected rate constraints for various different observing systems. these observationally constrained rates are then compared to the rates implied by local galaxy - merger observations.
inflation is the most commonly adopted and successful model to explain the problems such as horizon, flatness and monopole.   it is also known as warm inflation because of its ability to generate a nearly flat spectrum of primordial perturbations, which fits the observations of cosmological microwave background exactly. in this paper   we extend the warm inflation from canonical fields to a general noncanonical fields in @xcite and build a new and broader picture of inflation. with stronger hubble damping term and thermal damped term, stability analysis gave the even less restricted slow - roll conditions and a new but still scale - invariant power spectrum was obtained. the energy scale of inflation when hubble horizon crossing, the production of gravitational wave and consistency equation all acquire modification from both noncanonicals effect and thermal effect.. the non - gaussianity generated in the new picture has been fully researched and it s the main task of our paper.
we present a new algorithm for the analysis of functional data.   the algorithm is called boosting and it is based on the concept of a weak learner, which is a learner that is slightly better than random guessing. in this method,   we combine weak learners in such a way that the composite  boosted  learner performs better than the single weak learners. as a consequence, the number of boosting iterations is reduced. to evaluate the performance of the boosting algorithm, we compare the results of the previous two algorithms. by combining the two algorithms  , we can obtain estimates of the hilbert space of all square - integrable functions.
the entropy of entanglement ( eoe ) is the key resource for some of the most interesting tasks in quantum information theory, such as teleportation and dense coding.   it has been shown that the amount of nonlocality contained in a bipartite state subject to a superselection rule ( ssr ) can be quantified by only one additional number, the _ superselection induced variance ( siv ) : any two states can be interconverted asymptotically as long as the total eoe and _ siv are conserved. in this paper  , we extend this result to mixed states and show that it is possible to use siv as a resource which allows to overcome the restrictions imposed by the ssr on the conversion of quantum states with non - abelian particle number conservation.
high - mass x - ray binaries ( hmxbs ) are rare binary systems composed of an early - type massive star and an accreting compact object ( neutron star or black hole ).   they can be divided into several subgroups, depending on the nature of the massive star donating mass, which are found to depend fundamentally on the existence of a stable accretion disc. in this review,   we discuss the recent advances in our understanding of the properties of these systems, including the formation of wind accretion discs and the relationship between their orbital parameters and their physical properties.
quantum monte carlo ( qmc ) calculations of square - integrable " pseudobound " states in the @xmath9he system are presented.   the qmc calculations are based on the green s function montecarlo ( gfmc ) method, which is used to calculate phase shifts and reaction cross sections in a range of systems using effective two - body forces without explicit three - body terms. for the narrow resonances of the he isotopes,   these calculations are performed by approximating the true resonant wave function with a variational monteCarlo ( vmc ) calculation, in which a complicated but closed - form wave function containing large amounts of correlation is produced by minimizing the energy expectation value with respect to many variational parameters @xcite. at low energies, the vmc propagation drifts slowly toward the lowest available threshold ; even in very long gfMC propagations, the curve of energy  versus  @x Math15 for such states fails to flatten out at a " converged " energy.    the gf mc calculations show that this behavior is more pronounced for narrow states than for broad states, and they are consistent with the experimental results for the excited
resonant energy transfer due to dipole - dipole interaction plays a crucial role in many areas of physics, chemistry, material sciences and biology.   the theoretical framework to treat such processes is based on frenkel s exciton concept @xcite. however, internal and external degrees of freedom, e.g., internal vibrational modes of molecules and interactions with the surrounding solvent or proteins, have great influence on the properties of those systems and render a complete theoretical description challenging@xcite ( franck and teller et al., 2015 ). here  , we investigate the effect of resonance on the motion of rydberg atoms in regular and broken regularity chains using a mixed quantum / classical surface hopping method. for the regular chain, we estimate the initial forces as well as the kinetic energy of the system and present numerical results for the effects of the induced forces on the atomic motion. for both cases, we find that the first force is due to the resonant dipoles - dipoles interaction, which leads to the formation of an excitonic eigenstate of the chain by promoting the system into an exciton state by microwave excitation. when the disorder of the mutual interactions in the
the spica region ( spica nebula ) is a photoionized region around the @xmath2 vir, one of the brightest stars at a high galactic latitude.   the structure of the region has been studied in terms of the balmer recombination lines of hydrogen atoms, the observations of other optical forbidden lines and the infra - red fine - structure lines. in this paper, we analyze the far ultraviolet ( fuv ) absorption lines and emission lines as well as the wisconsin h@x Math2 mapper ( wham ) survey data to study the region around spica. for the fuv study, we use the same data set as the one used for our previous analysis of loop i superbubble ( l1, *????   * ) ; that data set is available at http://www.ncbi.nlm.nih.gov/geo/study/loopi_superbubble/wisconsin_h@x math2/l1.shtml/2013/14/12/8/spica_b nebula.html.    the results show that the region is ionized with a gas density of ~100.
we report a new method for computing the heavy quark - antiquark potential with higher statistics @xcite.   we work with 198 configurations of size @xmath4 in the presence of two flavors of conventional dynamical staggered quarks of mass, and show that the propagator of the light quark propagator at large@xmath2 is a two - channel correlator with a source and sink state " f" consisting of a fixedheavy quark- antiquark pair and an associated flux tube.    this state is shown to be the ground state for string breaking in qcd simulations.
we extend roth s theorem on arithmetic progressions in dense sets of integers to a two - dimensional, finite - field setting.   we elaborate on the ` density increment'procedure, obtaining a density increment on a set which is the intersection of sublattices in two distinct sets of bases. for a finite group @xmath9, we define the quantity @x Math10 to be the cardinality of the largest subset of its largest subset containing no _   corner_. a _ corner _ is triple of points of the form@xmath12 with @x math13.. we find an additional extension of this argument, and sharpen some inequalities to obtain our theorem.
ngc 4945 is a nearby edge - on spiral galaxy ( type sbcd or sabcd ) with an active galactic nucleus ( agn ) at the centre of the galaxy.   we present new and detailed x - ray observations of ngc4945 during orbit 205 ( 2001, january 21 ) for @xmath724 ks as part of the epic multi - detector optical and magnetic resonance ( mos ) and photonic ( pn ) mission guaranteed time programme. in the nuclear region of ngC 4945,   the presence of a large amount of emission associated with a starburst - driven superwind and a conical cavity protruding above the disk of the Milky Way is revealed by the detection of a wide range of soft to medium energy x - rays, including several discrete point sources of emission from the galactic disk. despite heavy obscuration at optical wavelengths, extended line - emitting gas co - spatial with the superwind   is detected in outflow along the galaxy s minor - axis, which is attributed to the interaction between the super winds and the surrounding medium.
electron beam induced current ( ebic ) measurements in thin film polycrystalline materials are challenging to study because of the large number of electron - hole pairs generated per incident electron, and the high injection of electrons into the material.   we have developed a theoretical model for describing the effect of high injection on the ebic response of thin film photovoltaics using a combination of numerical and analytical models in 1, 2, and 3 dimensions.    we find that the onset of the highjection regime is more specifically related to the product @xmath3, where@xmath4 is the majority carrier mobility, @x Math5 is the built - in potential, @Xmath6 is the sample thickness, and @x math7 is the system dimensionality.. we find an implicit expression for the recombination response as a function of total generation rate and beam position, and compare the model predictions to experimental results of cdte, and find qualitatively similar features.
quantum state sharing is an important and powerful security protocol for future quantum information systems. in this paper   we experimentally demonstrate @xmath7 threshold quantum statesharing in the continuous variable regime using einstein - podolsky - rosen ( epr ) entanglement, an experimentally accessible quantum resource that has been used in several quantum information protocols.   a secret coherent state is encoded into a tripartite entangled state and distributed to three players via quantum state Sharing. by using quantum resources,   any two of the three players can form an authorized group to reconstruct the state, and characterize this state reconstruction in terms of fidelity (@xmath8 ), signal transfer ( @x Math9 ), and reconstruction noise ( @Xmath10 ).    these measures show a direct verification of our tripartites continuous variable entanglements, which ensure that the quantum features of the secret state can be reconstructed by any two players in the authorized group.
we use the ir and x - ray images from recent space missions to explore the nature of the infrared ( ir ) emissions from supernova remnants ( snrs ) and the characteristics of their irx flux ratios.   the results show that the ir emission from the snrs is dominated by the dust - to - gas ratio ( dgr ) of the interstellar medium ( ism ), which is lower than that of the general interstellar medium in most of the cases. for the galaxy with a large magellanic cloud ( lmc ), the dgr of the ism is about 1.6 to 2.5 times lower than those of the galactic snrs, which are located in the galactic plane where the confusion from foreground and background emission is severe.
we present a new model of the absorption spectrum of seyfert 1 pg 1307 + 085 in sy1s and qsos using a constant density model of constant density.   we show that the observed spectrum is well fitted, considering that the narrow emission feature around 0.5 kev  the ovii complex  must be provided by another emitting region. for the other emitting region,   the wind implies too massive outflows ( near the eddington limit ) and the wind and the accretion models require an additional uv emission, which has to be supplied by a geometrically thin accretion slab.
the 2.16-m reflector is an english equatorial mount telescope at xinglong observatory, which was built / developed by chinese ourselves independently.   it has been used in various scientific research fields in galactic and extragalactic astrophysics, including the determination of stellar parameters, the discoveries of substellar and planetary companions of stars, studies of active galaxy nuclei ( agn ), the identifications of high - redshift quasars, discoveries and studies of supernovae, e.g., 1993j @xcite, as well as time - domain science ( e.e., supernova, gamma - ray bursts, stellar tidal disruption events, and variable stars ). since its first light in 1989,   the 2. 16-m telescope has played an important role in chinese astronomical observations. every year there are hundreds of chinese astronomers applying for observing time at the 2 to 3 m telescope, including significant numbers of new telescope users and graduate students. therefore, it is of great importance and useful to describe the specific parameters and the observing ability of the telescope and its instruments to the telescope users, which could be very helpful for planning and carrying out observations and for
we prove that the circular integral invariant is @xmath0-times continuously frchet differentiable in a neighborhood of the circle, seen as a mapping from the interior of the unit circle to its boundary.   this proof is based on an analysis of the differential invariant set of the cone area invariant, which is used in @xcite to encode the contour of a 2d object by the curvature function of its boundary curve. for the most common application of the integral invariants, e.g. object matching, we show that the uniqueness of the encoding is one - to - one.
we present an energy - conserving multiple relaxation time finite difference lattice boltzmann model for compressible flows with high mach number.   the model is based on the one proposed by kataoka and tsutahara, where the moment space and transformation matrix are constructed according to the group representation theory. in this model,   a single relaxation time ( srt ) is used to calculate the collision step and then mapped back to the velocity space. as a result, the advection step of the system is computed in the velocities space which is then transformed into a moment space using the transformation matrix. when the relaxation time @xmath0 is close to 0.5, the model works only for nearly incompressible fluids with very low mach number ; however, the simulation will be unstable if the relaxation times are close to 1.5. here  , we show that the mrt formulation of the model can be used to overcome the low - mach number constraint.
the existence and nature of melting transitions in two - dimensional ( 2d ) systems remains a topic of interest and uncertainty in both theory and experiments.   it has been predicted that thermal excitations of the shear modes of the vortex lattice should destroy off - diagonal long range order ( odlro ) in the crystalline state and the length scale over which phase coherence persists has been estimated. here  , we investigate this prediction using monte carlo simulations of thin film superconductors within the lowest landau level ( lll ) approximation using a spherical geometry to minimize finite size boundary effects. for the low temperature state below the first order transition,   the observed transition temperature is within the range investigated on the sphere. if so, then what are the reasons that different boundary conditions give different results?
the secco ( *?????   * b15a, hereafter ) survey is a survey aimed at searching for stellar counterparts of ultra compact high velocity clouds ( uchvcs ) of neutral hydrogen that have been recently proposed by different teams as candidate mini - halos residing in the local group or its surroundings.   we identified a candidate faint and blue stellar counterpart to an uchvc from the alfalfa sample ( hvc274.68 + 74.0 ) of the ( *???,b15a ) survey, which was previously identified as a star - forming and extremely gas - rich ( @xmath8 ) dwarf galaxy located in the virgo cluster of galaxies. using the spectroscopic follow - up of the brightest source of the system, by ( *?????)* b15b, we show that it is an hii region at the same velocity as the original cloud, ~7  km / s, hence physically associated to it. here we present the velocity field and the metallicity of several hii regions in both the main body ( mb ) and the secondary body ( sb ) obtained with the multi unit spectrosc
anomalous diffusion is a stochastic variable whose mean squared fluctuations increase with time.   it is generally recognized that underlying ( hidden ) processes are responsible for anomalous dynamics, but many theoretical approaches simplify the problem to effective equations for the observed variable, hoping to capture the multitude of underlying interactions. in this work   we consider a model in which subdiffusion is generated as a result of superposition of underlying modes with a broad range of time scales. using a well - defined mathematical model, we explore the long - time tails of the absorbtion probability @xmath7, as well as the asymptotic stable shapes of the probability density function ( pdf ) of the surviving walkers. by scaling the friction coefficients with wavelength  , we show that any value of@xmath3 can be generated by appropriate scaling of the friction coefficient with wavelength.
the blue phases are found in highly chiral liquid crystals between the high temperature isotropic fluid and the lower temperature cholesteric phases.   they are remarkable mesophases, exhibiting a brightly coloured texture of individual, micron sized platelets that indicates selective reflection due to a periodic structure, much like in an ordinary crystal, but with a much larger characteristic length scale. since the original analytic investigations,   the blue phases have been studied using de gennes @xmath0-tensor theory of liquid crystal phase transitions. here   we review the results of the recent re - exploration of the blue phase properties using the landau - degennes@xmath5-tensile theory of solid phase transitions for the first time.
source coding ( dsc ) refers to the compression of the outputs of two or more physically separated sources that do not communicate with each other.   driven by a host of emerging applications ( e.g., sensor networks and wireless video ), dsc has recently become a very active research area - more than 30 years after slepian and wolf laid its theoretical foundation @xcite. in this paper, we present a new practical scheme for solving the problem of source correlation using wyner s syndrome approach.
the structure and placement of rings and bars are widely believed to be governed by resonance.   this paper presents a test to identify galaxies whose corotation resonance ( cr ) is favorably placed for study ( within the bright disk ). in typical seeing,   the test requires only moderately deep imaging of the rotation curve shape and spiral pattern speed. when a suitable galaxy is identified, there is a good chance that its cr is well - placed within theBright Disk.    the test is not completely determinate : galaxies with cr within the Bright Disk can be missed.. however, it is reliable : when such galaxies are identified, they are more likely to have resonances at the same location as the bar pattern.
bose - einstein condensation ( bec ) is a phase transition that can occur in an ideal ( non - interacting ) bose gas, purely as a consequence of quantum statistics.   however, in reality, interactions are needed for the gas to remain close to thermal equilibrium and it is thus interesting to discuss if something close to ideal gas bec can be observed in a real system and what happens in the vicinity of the bec transition in the presence of inter - particle interactions. in this chapter   we review some recent experimental investigations using atomic bose gases that have sought to study the role of interactions on bec in the absence of inter- and interparticle interactions. while the results of these investigations have been very successful, the fact that ultracold atoms are confined using harmonic potentials has hindered the study of the process of bec itself. in particular, the existence of inhomogeneous density distributions often masks the most interesting interaction effects and also makes direct comparison with theory challenging. in order to understand the experimental results we focus on the statistical mechanism of the Bec transition, the transition temperature, and the critical behaviour near the transition.
the panda barrel time - of - flight ( tof ) detector for the facility for antiproton and ion research ( fair )  @xcite is one of the four major experiments being constructed at the gsi helmholtz centre in darmstadt, germany.   the detector will be located in between the dirc detector and the electromagnetic calorimeter ( emc ) at a radial distance of about 50 cm from the beam pipe with a total area of about 5.2m@xmath9 using a proposed design of a scintillator tile ( scitil ) hodoscope composed of 5760 small plastic scintillation tiles with sizes of about @xmath8, covering a total surface area of five.2 m@x Math9.    the detector has been tested in a 2.7 gev / c proton beam at forschungszentrum jlich using a prototype based on the optimization studies performed by monte carlo simulation and experiment. 	 the results show that the proposed detector can be successfully designed and fabricated using silicon photomultipliers ( sipms ) with a sensitive area of @x math1 and a time resolution
quantum light and quantum gas are two broad and intensively developing fields of modern physics.   quantum optics with quantum gases will close the gap between standard quantum optics and quantum atom optics, where the role of light and matter in the interaction is essentially reduced to a classically auxiliary tool. as both light and atoms will be considered at the quantum level, quantum optical experiments with ultracold quantum gases can be considered as an ultimate quantum limit of light - matter interaction, which became experimentally feasible only recently, when a bose - einstein condensation was coupled to the light mode of a cavity @xcite. here  , we summarize our results on light scattering and outline some perspectives by presenting several particular cases and using simple physical models and interpretations.
the io plasma torus is a dense ring of electrons and sulfur and oxygen ions trapped in jupiter s strong magnetic field, produced by the ionization of @xmath01 ton per second of neutral material from io s extended neutral clouds. on ionization, fresh ions tap the rotational energy of jupiter ( to which they are coupled by the magnetic field ).   much of the torus thermal energy is radiated as intense ( @x Math010@xmath3 w ) euv emissions, while the electrons have very little energy at the time of ionization and gain thermal energy from collisions with the ions ( as well as through other plasma processes ). here  , we present an analysis of uvis observations of the io torus from 1 october 2000 to 14 november 2000. for the first time, we show that the azimuthal variability of torus emissions is related to the underlying source, loss and transport processes, and that the observed temporal variation in torus emission can be used to predict the rotation period of j Jupiter.
the well - known camassa  holm equation for the propagation of shallow water waves, @xcite, is an integrable infinite - dimensional hamiltonian system whose solitary waves are solitons.   it is known to possess global solutions, but it is not apparent how to obtain global control of the solutions of equation, owing to its involved structure and due to the higher order nonlinearities. in the present paper   we show that a variety of novel traveling wave solutions can be obtained for every speed given by the wave speed and the level of the undisturbed water surface, allowing us to define the exact regions in this parameter space which give rise to the following types of waves : solitary waves with compact support, solitary waves of elevation and solitary waves from depression.the proof of these results hinges on the observation that for traveling waves, equation may be written as an autonomous hamiltonia system involving two parameters.    this insight allows us to explicitly determine bounded orbits in the phase plane in the form of regionsampcp(0.65 ), where regions are defined by the existence of single solitary waves and the state of the free surface is determined by the number of times the wave speeds exceed the
the nature of spin correlations and their relationship to superconductivity in layered cuprates remains controversial.   we have used elastic neutron scattering measurements on a crystal with a single orthorhombic domain to test the character of the spin excitations in the  ( ybco ) family of cuprates, using a triple - axis spectrometer to measure the dispersion of low - energy and high - energy magnetic dispersion in the cuo@xmath3 plaquette for the under- to optimally - doped cuprate, @xmath9.@xcite. by performing inelastic neutron scattering experiments on arrays of detwinned single crystals, we have shown for the first time that the incommensurate antiferromagnetic wave vector is oriented along the  direction, with the excitations centered about the antifreeze wave vector. at low energy,   the wave vector shows a downward dispersion toward the center of the hourglass, whereas at high energy the wave vectors show an upward dispersion away from the center, which is consistent with the existence of a two - fold rotational symmetry between the two states. at all energies below the superconducting
hh  111 is a herbig - haro ( hh ) jet that was observed at gemini north observatory on oct 2007 and nov 2010, using the gmos instrument in integral field unit ( ifu ) mode under the program gn-2007b - q-9.   we used the ifu in the single slit mode with the r831_g5302 grating, giving a @xmath7 resolution at 7570. the observations are presented in the form of high resolution spectroscopy with full spatial coverage for the  6730, 6716 ; h@xmath2 ;  6583, 6548 and  6360, 6300 emission lines, and have a high enough signal - to - noise so that velocity channel maps can be generated. from these maps, we show that the hh  111 system has a one - sided jet that appears at @x math3 from an obscured source, extending to a distance of @x Math4 w from the source.    the kinematics of the jet are studied spectroscopically by combining two different types of data reduction methods : the first one is based on
the optical response and the ablation threshold of bulk and thin - film @xmath2-quartz ( having different thicknesses ) on being irradiated by femtosecond ( fs ) laser pulses in the intensity range of@xmath0 to @x Math1 are investigated using first - principles simulations computed from fundamental equations.   a multiscale approach using the wave equation and the time - dependent density functional theory ( tddft ) is applied to calculate directly the density of the conduction band ( cb ) electrons generated in the optical medium, which is then used to calculate the reflectance, the cb electron density and the absorbed energy based on some criterion for laser - induced ablation. at very low intensities below @x math0, the optical properties of the medium follow a linear response to laser intensity variation @xcite, but start showing a nonlinear response as the laser intensity increases beyond a certain level @x maths1. at higher laser intensities of greater than @xMath4, the material suddenly starts behaving like a plasma medium, and its optical properties follow the properties of a plasmonic medium @xcites. by comparing the absorbed energies based on an empirical criterion
in a recent paper @xcite we proposed a model of projectile mutifragmentation which was applied to collisions of ni on be and ta at 140 mev / nucleon and xe on al at 790 mev/nucleon.   the model gave reasonable answers for most of the cross - sections studied. in this article   we improve the model by incorporating an impact parameter dependence of @xmath1. while we were led to this by computing the cross-sections of very large projectile like fragments ( which can only result from very peripheral collisions ), the effect of temperature dependence is accentuated in other experiments. here   they are compared with experiment.
angular momentum is a very important concept in dynamics of particles and within quantum mechanics its properties are very well understood.   one example where the theory has direct application is the rigid rotor model, which is basic for understanding rotational spectroscopy and collisions of molecules. here   we present a new formulation of the wigner function for the distribution of angular momentum in the phase space from which transition probabilities can be calculated from classical mechanics.
the baryonic fraction density estimation from the cosmological parameter extraction from the cmb experiments is based on the simple idea that the distribution of matter ( including dark matter particles and baryons ) is practically homogeneous for all scales, except some fluctuations leading to the galaxy and large - scale structure formation.   typically, these fluctuations are assumed to be adiabatic ones. in this paper   we show that there are some peculiar modes of perturbations in the composite fluid which compensate the baryonal perturbation potential, i.e., the condition @xmath25 for some @x Math26 component of the cdm particles mixture. 	 we call below this mode as a compensate isocurvature mode ( cim ) for the @x math26-component of the dark matter particle.    we also show that the cim can be considered as a compensatory mode if several components of thedark matter particles take part in the same composition of the black body radiation and the cmp2/cdm mixture.
we develop an efficient algorithm for the calculation of the interactions forces at all contact points within a three - dimensional deposits of polydisperse ellipsoids and use it in a molecular dynamics ( md ) method to perform our simulations.   we show that the density and coordination number of the deposits behave similarly to what is observed in jammed systems, although the shape of the particles deviates from the sphere with a non - negligible polydispersity in their sizes. however, in contrast with randomly constructed jambed systems, deposits become strongly anisotropic when the shapes of the nanoparticles deviate from the spheres. furthermore, we find that the size polydis Perspersity plays a minor role when compared to the shape.
we investigate how the predictability of susceptible - infectious - recovered ( sir ) processes evolves with the outbreak itself.   we assume a disease spreading over a static underlying network represented as a graph, @xmath4. in particular, we consider two senarios in which the state of each individual is known : one in which only the fractions of currently infectious, recovered, or susceptible individuals are known, and the other in which both the fraction of infected individuals and the number of vertices in the network are known. using the configuration model   random networks with an arbitrary degree distribution , we find that the outbreak turns out to be completely predictable in the long - time and large-@xmath0 limits  . however, the major uncertainty is in the very beginning, whether the outbreak would die out immediately or not.see research article http://www.biomedcentral.com/1471-7007/9/8/5
the @xmath2-invariant and the@xmath0 models in two dimensions have been studied intensively during the last 20 years.   most important both types of models were found to be asymptotically free @xcite, but recent work has suggested that they have a weak coupling limit distinct from that of the non - linear @x math3-models in two dimension. in the following   i give evidence that rules out the scenario presented in @xcide. for a particular type of the action of the @x Math2 and the @Xmath0 model   I show that the models are exactly equivalent for sufficiently small coupling.    i discuss the scaling properties of vortices of the #xmath 0 model with standard action in the weak coupling regime.. i give numerical results for the step scaling function introduced in ref.,@xcite that supports that the constraint model gives the same universal results as the standard action.
the transport of mass and angular momentum in accretion disks remains one of the least understood processes in modern astrophysics.   it is currently believed that the magnetorotational instability ( mri ) is responsible for driving the magnetohydrodynamic ( mhd ) turbulence required for efficient angular momentum transport in astrophysical disks. here  , we investigate the saturation of the mri in a viscous, resistive plasma in the quasi - ideal and resistive regimes by means of a systematic study of the parameter space involved. using a combination of numerical simulations and analytical and semi - analytical work, we identify the existence of a critical elsasser number of order unity and show that kelvin - helmholtz and tearing modes dominate in both the quasi- and resistative mhd regimes, respectively. by studying the scaling laws that describe the behavior of the fastest growing parasites in these limits,   we reveal that the rate constants of the parasitic modes are determined by the asymptotic behavior of their interactions with the mr instability. to test this hypothesis, we apply the same scaling laws to the case of a non - linear, incompressible mhd fluid under sub - equipartition magnetic fields.
the raman scattering experiments of high@xmath1 superconductors@xcite show some qualitative differences with the line shape of previously studied antiferromagnets of spin @xmath2.   this is due to the broad linewidth of the excitations, and the long tail of the spectrum that extends beyond the energy of four magnon excitations. in this work,   a two  dimensional ( 2d ) doped heisenberg model for spin @Xmath0 is used to calculate the raman cross  section in finite lattices using cumulant expansions on a heisenburg model with diagonal next neighbor couplings.    the results are in good agreement with the experiment, and show that the quantum fluctuations of the spin   phonon interaction can be accounted for by averaging over configurations with equal weight.
the spectrum of quasars and seyfert galaxies shows strong emission lines superimposed onto a bright continuum.   the continuum contains a significant feature in the optical - ultraviolet region, known as " the big blue bump ". due to the huge photoelectric opacity of the galaxy, the spectral energy distribution ( sed ) of the ionizing continuum, between the lyman limit and the soft x - rays ( euv  x ),   is hardly known. owing to the redshift effect and the transparency of the quasar environment, it has been possible to infer the sed down to @xmath1350.. a striking feature of the composite quasar sed is that a significant steepening occurs around 1100, leading to a far - uv powerlaw of index@xmath3 ( @x Math4 ).    the far - Uv break is clearly seen in individual spectra., the amount of steepening varies considerably from object to object. here   we review below possible absorption mechanisms that would give rise to the break and at the same time allow the emergence of an upturn in the extreme - uve, in order that the ionization sed be as hard as needed in
the blue compact dwarf ( bcd ) phase is a conspicuous event in the life of otherwise mean dwarf galaxies.   it is not yet clear which objects eventually change to glow as bcdgalaxies ( i.e., which galaxies are bcds during quiescence ). identifying them seems to be a necessary first step to answer the question of why a galaxy experiences a bcd phase. here   we try to answer two specific questions : ( 1 ) are there galaxies like the bcd host galaxies without the conspicuous starburst observed in bcds? ( 2 ) if the answer were yes, what are the physical properties of these ( putative ) bcd galaxies during quyingcence?   this paper aims to answer these questions using a new approach to investigate the linage of the bcds. rather than directly comparing the properties of thebcds with properties of known galaxy types, we attempt a blind search for galaxies that look like precursors or left - overs of the b cd phase, paying minor attention to the galaxy class. by searching the sdss / dr6 database for candidates, we find a sample of quiescent bcdGalaxies ( qbcd ) and a control sample
the scarring phenomenon of quantum eigenstates of classically chaotic systems is a well - known consequence of random matrix theory ( rmt ).   it is the natural quantum manifestation of complete classical uniformity on the energy hypersurface for chaotic systems, and has been seen in many experimental work in microwave cavities, tunnel junctions, and the hydrogen atom in a uniform magnetic field. here   we review the work by fishman, agam, and co - workers@xcite, which has provided additional perspectives on the concept of scarring, and a proposed measure for it.. the main points of this paper are ( 1 ) to point out that very often the original linear theory, together with a proper account of gaussian fluctuations and symmetry, is sufficient to understand scar strength ; ( 2 ) to show that scarring stronger than this may sometimes be understood in terms of identifiable _ nonlinear _ homoclinic recurrences associated with a given periodic orbit, the effect of which will turn out to be @xmath4-dependent ; ( 3 ) to firm up the existing definitions and measures of scars ; and ( 4 ) to extend the notion of scarred structures to classical structures associated
the power of multi - wavelength photometric observations to recover galaxy redshifts has been known since the late fifties @xcite and it has been confirmed in the last decade with deep blank - field imaging surveys.   the aim of this work is to assess the impact of different _ james webb space telescope ( _ jwst_ ) broad - band filter combinations on recovering reliable photometric redshifting for all the observed sources using the near infrared camera ( nircam ; *??? * ) and the mid infrared instrument ( miri ; *????   * ; *?, the results show that the use of a combination of two or more filters in the near- and mid - ir range can be used to recover the right redshifted galaxy spectral energy distribution ( sed ) distributions for most of the observed galaxies, but there is a significant difference in the sensitivity of the miri filters compared to those of the nircams. while the latter are the most sensitive in the short - wavelength bands, the latter have a lower sensitivity than the former, making it less convenient to invest time on long miri observations when planning deep galaxy surveys. at the same time, the lack
n66/ngc346 is the most massive and active star forming region in the small magellanic cloud ( smc ).   the upper end of its stellar mass distribution has been well studied in the recent years, but little is known of the low end of the distribution. to answer this question we began a comprehensive investigation of star formation in the smc, from the ground and with high - resolution spectroscopy ( hst ). using the hst / acs wide field channel, we obtained deep images of ngc346 in the broad band filters f555w ( @xmath7v ), f814w (@x Math7i ), and f658n ( @Xmath7 h@xmath0 ). here   we present the first results on these images, which show an unprecedented level of detail in the ngc 346/n66 complex. at the center of the cluster   are at least three subclusters, and a myriad of small compact clusters is visible throughout the region. some of these clusters appear to be still embedded in dust and nebulosity, and they might be sites of recent or ongoing star formation.
general relativity can be quantised by canonical or covariant methods depending on whether one regards space or space - time as more fundamental.   the aim of this paper is to show that the generalised projector of the hamiltonian constraint of loop quantum gravity can be regularised so that it describes a sum over space- and time - time triangulations. in this way   it can be used to decompose the projector into a product of " small " unitary local proper time evolutions. acting on an initial triangulation, each elementary evolution corresponds to a gluing of an @xmath18-dimensional simplex to the boundary. in order to explain the relation between the spin - foam and the canonical theories of quantum gravity  , we provide two different regularisations of the projector such that its matrix elements are given by a sumover triangulated geometries of the cylinder on the cylinder with boundary geometrievers.. the amplitudes of the triangules are then given by the dynamical triangulae and thespin - foam models respectively. using these regularisations   we show that all the properties of the spin foam model are consistent with the results of the canonical
we establish the almost sure box - counting dimension of two random models of self - affine box - like carpets in the sense of fraser   @xcite.   the first model is a bedford - mcmullen construction with random translation vectors that keep the column structure intact and the second one is a homogeneous, random recursive, and fractal percolation of self-affine carpets. by choosing different subdivisions of the iterated function system ( ifs ) that make up the @xmath14 and@xmath15 for the bedford / mcmullaen type of self sets, we show that the hausdorff, packing and box dimensions of the two models coincide almost certainly ( with respect to the chosen translation vectors ) with the ` affinity dimension'of the set. under these conditions   it is shown that the box dimension of the homogeneously random version of the @Xmath0-variable versions of the self - Affine box can be reduced to the expectation of the dimension of all the attractors of the individual attractors when all the ifs have the same subdivision parameters. on the other hand, this holds in a more general setting for
physical cosmology is the branch of astronomy concerned with the large scale structure and evolution of the universe.   it is unique in that two apparently disjoint disciplines  the physics of the very small and the physics for the very large  are both needed to achieve our current understanding of how the universe has expanded since the big bang. however, there is a cloud on the horizon called dark energy, which is a form of energy that pervades the universe and is driven by the cosmological constant @xmath1. here   we present a new model of dark energy based on the friedmann equation and the associated friedmann - lematre - robertson - walker metric ( @xcite, @x Math3, \label{eq : metric}\ ). using time - varying  constants  , we show that the standard model of cosmology does not account for the observed fainterness of type ia supernovae, which suggests that dark energy is driving the acceleration of the expansion rate of the cosmos.
the luminosity function of the field population ii m subdwarfs is determined using data from a new proper motion survey based upon plates taken as part of the first and second palomar sky surveys.   the results show that the population ii halo stars have a mass function near the hydrogen - burning limit, which is consistent with the predictions of schmidt ( 1975 ) and bahcall & casertano ( 1986 ). in this paper, we compare our results to those of other published studies and discuss their significance.
the quantum annealing algorithm ( qaa ) is a promising candidate for a vast number of potential real world problems.   all of the potential applications are too numerous to list here, but include fields as diverse as aerospace, machine learning, pure computer science, and economics. in this manuscript  , i propose an alternative way of using quantumAnnealers to solve problems.the qaa as it is currently structured starts from a superposition state of all possible solutions. the system is then annealed such that quantum fluctuations are introduced through competition between an ising model problem hamiltonian, with field variables @xmath1 and coupler variables@xmath2 and a non - commuting driver hamiltonians. 	 tunneling mediated by these fluctuations is then driven by a low temperature thermal bath.    one example of such a system is the transverse field ised model, which is currently implemented on the annealering qubits produced by d - wave systems inc. erythromboselective annealer,    @xcite, where @x math4 is the anneaaling parameter which controls the annaling schedule, and both behave monotonically with
a quadtree is a data structure formed by starting from a single square, and recursively dividing squares into four smaller squares.   quadtrees are typically used in finite element meshes, but other applications may give rise to unbalanced quadtree - structured data structures. the four - color theorem for planar maps implies that edge - adjacent quadt trees require at least four colors, regardless of balance. here  , we show that balanced edge- and corner - adjacent quads require only three colors, while even unbalanced corners require at most five colors. using simple linear time algorithms, we also show that 4-color edge - neighbor - adjacent unbalancedquadtrees can be colored with four colors so that no two neighboring squares sharing an edge have the same color.graphical abstract
noncommutative field theories are becoming increasingly popular recently and are believed to be reasonable candidates for planck scale physics.   the main idea is that in the scales where quantum theory and general relativity are no longer independent, the notion of a point in space - time becomes meaningless and a finite minimal length or uncertainty relation will have to be postulated for the coordinate functions in order to prohibit the localization of points with arbitrary high precision. here  , we propose a new approach to recover the wilsonian effective action of noncommutatives by integrating out the high energy modes of the theory. at energies below @xmath0, the effects of ultraviolet and infrared divergences are decoupled from each other and there is no mixing between them. beyond the scale @x Math10, the non commutative theory breaks down and the effect of gravitational effects is comparable to those of the rest of the fundamental interactions.
photonic states are suitable to carrying quantum information for their flexibility and robustness against decoherence effects.   the flying qubits in various quantum computing schemes are encoded in photonic states @xcite, and many tasks in quantum cryptography and quantum communications are performed with the aid of photonic state as well. a significant advantage in using single photon states of multiple spatial modes is that arbitrary unitary operation on such states can be deterministically realized with a linear optical device. here   we discuss the methods to realize such transformations and some of their useful applications.
the ads / cft correspondence(or gauge / gravity duality ) @xcite is a duality between the super yang - mills theory and the type iib supergravity in the anti - de sitter space at the large thooft coupling and large @xmath3 limit, which has been widely utilized to tackle strongly coupled systems.   although the ideal hydrodynamics successfully describes many properties of quark gluon plasma ( qgp ) based on experimental data, further studies suggest that the medium should be anisotropic in the early times during the formation of qgp @xcites.. the energy loss of hard probes in such strongly - coupled anisotropic plasma described by holographic models has been investigated recently. here  , we present the numerical results of stopping distances of light probes at mid and large anisotsropy in the anisotropic dual geometry introduced from@xcite. for the isotropic case,   the maximum stopping distance of a massless particle falling along the null geodesic in the dual geometry can be characterized by a maximum jet quenching parameter obtained from a trailing string moving in the non - linear plane with respect to the
the picture of strongly correlated localized or nearly - localized electrons is the base of a successful theoretical description of both high - temperature superconductivity and magnetism.   in almost all cases the appertaining localized electron states are represented by atomic orbitals that define, for instance, partially filled @xmath0-,@xmath1-, or @x math2- bands.    another option would be to represent them by best localized and symmetry - adapted wannier functions. here   we investigate the special symmetries of best localized wanniers within the band structures of various elemental superconductors and of the ( high - temperatures ) superconductor la@x Math5cuo@x maths6  @xcite.. the results show that the symmetry of the best localized echogeny functions within the superconducting bands of the transition metals does not necessarily tell anything about the physics of strong correlated localized electrons.
in this paper, we investigate the graph list colouring problem in the on - line setting.   the vertices of a graph are pre - assigned lists of colours, and the task is to properly colour the graph so that every vertex receives a colour from its list. in what follows,   we study the problem from a theoretical point of view and resolve several open questions on this subject.
the baryon oscillation spectroscopic survey ( boss ) experiment of the sloan digital sky survey ( sdss ) collaboration has recently provided new evidence against the @xmath0-cold - dark - matter ( @x Math0cdm ) model of cosmology.   this is based on the measurements of the baryons acoustic oscillations ( bao ) flux - correlation function of the lyman alpha ( ly-@xmath1 ) forest from quasars at high redshifts. in this study, we explore the phenomenological implications of the results from boss for an interaction between dark energy and dark matter using a lagrangian model of interacting dark energy. since this model allows for one of the components to decay into the other, we claim that energy flow from dark energy to dark matter implies a smaller amount of dark matter in the past, thus accommodating for the value of the hubble parameter at @x math14 found by boss and still maintaining the cosmology today close to @x maths0cdms. as a result, we propose a new model of the evolution of the universe with a negative energy density for the dark matter component, which is consistent with the results of boss.
the study of quasiparticle physics and the dynamics of polarons and molecules in fermionic medium has received much theoretical and experimental attention.   however, all studies concerning the first order nature of the polaron - molecule transition in a three - dimensional ( 3d ) fermion medium involve variational ansatz with some approximations that is ultimately not justified in low dimensions. in this paper, using exact bethe ansatz ( ba ) solution, we rigorously study fermi polaron and molecule states in a 1d ferm ionic medium. for weak attraction,   the single spin - down impurity gets dressed by the surrounding spin - up fermions to form a Polaron - like quasipsarticle. however, as the attractive interaction grows, it binds with only one spin -up fermium from the medium to gradually form a tightly bound molecule. in comparison with the previous study  @xcite, here   we analyzetically and numerically calculate thePolaron energy, the binding energy, and the effective mass for this impurity problem. moreover, we obtain an explicit form of the ba wave function of the singlespin - down immersed in the fully - polarized
impurity- and pressure - induced magnetic orderings in tlcu@xmath9mg@x Math10cl@x math2 with an excitation gap of @xmath8 k are studied.   the parent compound is a spin singlet spin dimer system with an antiferromagnetic intradimer exchange interaction @xMath12 k @xcite. at ambient pressure, tl cu@x maths9mg=xmath10cl<xmath2 is paramagnetic down to zero temperature because of the spin gap ; however, it undergoes magnetic ordering under hydrostatic pressure under the influence of nonmagnetic impurities @xaite.. the critical pressures obtained through magnetization measurement and a neutron scattering experiment indicate that the pressure -induced magnetic ordering in tlcu@x mathematics9mg#9mg+@x mathematician10cl>xmath17 is a quantum phase transition due to the closing of the spindle gap.
we report on observations of the radio afterglow of  on a timescale of 60 days to 366 days. using these observations in conjunction with the earlier radio data @xcite, we are able to infer a geometry - independent estimate of the total energy of the gamma - ray burst ( grb021004 ).   this estimate is based on the observation of a significant flattening of the late - time radio light curves at @xmath11 d, especially when compared to the steep decline measured at early times at higher frequencies ( 22.5 - 250 ghz ) where the temporal slope @x Math12 ( with @x maths13 ) at ~1.43 ghz is achromatic, except at 1.43 g where the light curve was still rising, reaching a maximum near 300 d. the decay index changes from @x math19 to@xmath20 between 1.24 and 37 days and 37 and 258 days after the burst @xcites.    the decay rate decreases from ~2.0 to ~1,000 j / cm2 over the course of the observation period, which is consistent with the hypothesis that the central engine of the burst is a long - lived central engine
the orbital period derivative of the low mass x - ray binary ( lmxb ) x1820@xmath0303 in the globular cluster ngc  6624 is measured for the first time.   the results show that the orbital period of the system has apparently decreased by @xmath10 milliseconds over the last 7.1 hr, and that the orbit in is evolving at a rate that is considerably faster than theoretical predictions for systems undergoing conservative mass transfer.
the rule184 cellular automaton ( ca ) is a prototype of deterministic model of traffic flow.   it shows a complex phase transition from free to congested state, and many theoretical models have been proposed so far. among them  , we propose a multi - value generalization of the rule184 ca by using an ultradiscrete method@xcite. in this method,   the free parameter @xmath6 is assumed to be a positive integer constant, and the number of cars at each site is considered to be the length of each site. for each site, the time constant @x Math6 is set to be equal to the real number of car at site @x math4 and the distance constants @x maths5 and @xMath6 are assumed to Bezier's number of sites. as a proof of the proposed method, we show that the experimental phase transition observed in real data can be used to judge whether a ca is suitable for traffic model.
transit measurements are currently corrected to the heliocentric julian date ( hjd ) to account for finite light travel time differences with the earth s orbital phase, but they are not corrected for the ( smaller ) effect of parallax.   although this should not have significantly biased current transit measurements, it may become increasingly important for both high - precision transit timing and the characterization of planets in orbits approaching 1 au from their parent stars. while the exact nature of the effect is not fully understood, it is generally assumed that the orbital plane of the exoplanet system is co - planar with that of the earth - sun system, and the transit timing difference between observers at different locations on the earth is small enough to be easily accounted for by photon counting statistics. here   we briefly state the nature and approximate magnitude of these effects and discuss their potential uses.
@xcite ( 1981 ) discovered that globular clusters ( gcs ) in the milky way are divided into two distinct groups according to the mean period ( @xmath1 ) of type ab rr lyrae variables.   the oosterhoff dichotomy is caused by the luminosity difference between the two groups, which can be explained by the population - shift effect within the instability strip ( is ) with increasing metallicity. however, it is not clear whether this population - Shift effect applies to all gcs in addition to the two outer halo gcs representing two oosterhof groups, m15 and m3. here  , we show that the observed dichotomy can be reproduced by using synthetic horizontal - branch models, and that the results are consistent with the hypothesis that the origin of the dichotomy could be related to the presence of multiple populations in gcs. based on these results, we propose new constraints on the star formation time scales for the inner and outer h Halo gcs, and discuss the possible mechanism of the observed period - shift between the metal - poor group ii gcs and the relatively metal - rich group i gcs.see research article http://www.ast
the ground - state ( gs ) structure of a magnetic nanosystem in two dimensions ( 2d ) is determined by taking into account the short - range exchange interaction, the long - range dipolar interaction and the perpendicular anisotropy in 2d.   the results show that the gs configuration in magnetic nanodots is influenced by the size of the sample, the relation between the exchange and dipolar interactions, and the type of crystal order taken into account. at the same time, the temperature of the phase transition from a capacitor - like state to a planar vortex with core is affected by the shape of the nanodot.
black hole evaporation@xcite was one of the most surprising predictions of the field of quantum field theory in curved backgrounds.   since the phenomenon has not been observed experimentally, it is of crucial importance that the assumptions underlying the prediction be examined especially carefully so as to try to understand the process as deeply as possible.
the joint power and admission control problem is known to be np - hard to solve to global optimality in cellular, ad - hoc, and cognitive underlay networks.   the current formulation of power control aims to use a minimum total transmission power to support all links in an interference network at their required sinr targets while using a minimum number of simultaneously supportable links at their desired sinr levels. here  , we propose a new deflation algorithm based on @xmath2 (@xmath3 ) norm minimization for the jointPower and Admission control problem. compared to the existing approaches, the proposed algorithm is more efficient in terms of the number of supported links, the total transmitters and receivers, and the cpu time.
a carousel is an automated storage and retrieval system, widely used in modern warehouses.   it consists of a number of shelves or drawers, which are linked together and are rotating in a closed loop. the picker ( human or robotic ) controls the carousel and selects the items that need to be retrieved from the shelves. as a result  , the carousels are highly versatile and come in a huge variety of configurations, sizes, and types. in this review paper   we focus on the modelling and the performance of carousel systems. in particular, we discuss the problem of choosing a reasonable picking strategy for one order and a single carousel, where the order is represented as a list of items, and by order pick strategy we mean an algorithm that prescribes in which sequence the items are to be retrievable.we also present a general probabilistic approach developed by litvak _   et al. to derive the probability distribution of the travel time in case when items locations are independent and uniformly distributed.
we study the possibility of a two - dimensional ( 2d ) phase of quantum spins and itinerant fermions or bosons with singular surfaces in momentum space.   we show that the spin correlations of these particles exhibit singularities along surfaces in their momentum space, analogous to the fermi surfaces in a quasiparticle phase. when the system is placed onto an @xmath0-leg ladder, the singular surface of the 2d phase is already manifest on the ladder by cutting through bose surfaces in some anisotropic 2d system placed on a ladder with a large number of gapless one - dimensional modes. using a d - wave correlated bose liquid ( dbl ) construction of the itinerant uncondensed dbl, we find that the oscillatory power law decays of the dbl are governed by a set of discrete momenta that cut through the singular ground state of the 1d phase at a distance of ~1.5 mm from the parent 2d state. for the un - coupled mean field states of the slave particles,   the same phenomenon is observed, but the time - dependent decay of the power law is much more pronounced. as a consequence, the present work
the evolution of the x - ray luminosity function ( xlf ), using an improved version of the mass function and m - t relation, obtained in del popolo ( 2000a ), del popoloski ( 2000b ) and lacey & cole ( 1993 ), is studied.   the results obtained for @xmath0 and other cosmological parameters are in many cases discrepant the one with the other. to check the previous trend,   i have also estimated the value of@xmath13 following borgani et al. ( 2001 ). analyzing the rosat deep cluster survey ( rdcs ) and using the xlf to obtain constraints on cosmology parameters, borganis et al. ( 2001).using their method and data, but our mass function as a function of the number density, we find that @x Mathiesen and evrard s ( 1998 ) results are not consistent with the ones obtained by reichart s ( 1999 ) analysis.
the conjecture of toeplitz @xcite ( also known as the square peg problem or inscribed square problem ) that a subset of the plane can inscribe a square if it contains the four vertices of a square of positive sidelength is solved.   the squares with vertices on the curve are considered in the context of the general case of conjecture , which is to say that under some suitable genericity and regularity hypotheses, there are an _ odd number of squares with Vertices lying on the curved surface of a curve. here  , we show that the proof of the conjecture is not always straightforward, but that the answer can be obtained by taking into account the possibility that the squares in the approximating squares degenerate to a single singular point in the limit.
the question of a universal mass function of astronomical objects has been of interest only to fritz zwicky since his 1942 paper on the large scale distribution of matter in the universe.   he argued that the luminosity function of galaxies had to be essentially exponential, i.e.  ever fainter galaxies being increasingly more numerous, just as observed today, but in contradiction with the data available then, which showed a more gaussian - type lf for galaxies. here   we show that by proper normalization we can indeed establish a continuous mass function from @xmath4 ( 100 meter - size asteroids ) to at least@xmath5 ( the most massive clusters of galaxies ), and that there is surprising similarity in the slope of the mass function over a large range of mass. this degree of universality in the mass distribution of cosmic objects   does not entitle us to conclude that there indeed is a " universal " mass function beyond the scale of galaxies and systems of galaxies, but rather that the distributions of these objects are shaped by totally different physical processes.
the concept of self - organized criticality ( soc ) is a simple way of modelling slowly - driven out of equilibrium systems.   the ultimate hall - mark of soc is the observation of finite size - scaling, indicating a true critical dynamics. here   we present a two - dimensional ( 2d ) system, the surface of a 3d pile of rice, showing both roughening behavior and avalanche dynamics, which can be studied in terms of the avalanche size distribution for different sizes of the field of view, @xmath7. using an array of hall - probes, we find that the avalanche dynamics exhibit power - law scaling in their avalanche distributions, which is consistent with the results of the finite size scaling analysis obtained from the kardar - parisi - zhang ( kpz ) equation. however, the roughness and growth exponents of the surface are also found to be affected by the size of the avalanches, which are observed in the propagation of the front of the rice - pile. this is shown by the determination of the critical exponents, describing the dependence of the cutoff scale on @x Math7, and the exponent of the Avalanche size distribution.. the connection between these
electron - hole pairs form tightly - bound excitons in single - walled carbon nanotubes, and they exhibit many interesting phenomena such as single photon emission from quantum - dot - like states, brightening of luminescence by trapping sites, and spontaneous dissociation.   we perform systematic investigation of exciton diffusion, end quenching, and exciton - exciton annihilation ( eea ) in individual air - suspended single - wallsed carbonnanotubes by photoluminescence ( pl ) microscopy using an automated optical measurement system. to characterize the unique nature of the one - dimensional diffusion in carbon nanosheets, we identify the chirality distribution of individual nanotube samples by scanning electron microscopy and spectroscopy, and we derive an analytic model for length dependence of pl intensity through comparison with experimentally observed excitation power dependence. at the same time, we study the rate of eea process by performing monte carlo simulations and find that the rate is much higher than experimentally reported. a new analytical expression for excitation energy dependence of fluorescence intensity   is also derived.
the entropy of a reissner - nrdstrom type black hole is studied in the modified dispersion relation ( mdr ) obtained in @xcite using the generalized uncertainty principle formalism.   the results are compared with those obtained in a previous study of the same model where the terms proportional to odd powers of energy are not present in the mdr and we concentrate on the entropy of the brane - world black hole solution.
we study the collisional relaxation of a self - gravitating system in @xmath17 dimensions.   the interacting potential is the solution of the poisson equation in this dimension, where the coupling constant is the number of particles. using simulations imposing radial symmetry ( particles conserve their initial angular momentum ), we find that the relaxation time scales with the size of the system, i.e., for some initial conditions it has been found to scale as@xmath8 and for other initial conditions as @x Math5. at the end of the relaxation process   there is a general formation of a quasi - stationary state ( hereafter qss ), which is then relaxed to thermodynamical equilibrium in a timescale of order.
the interferometric interferometer for the study of gamma - ray scattering ( ibis ) is a new system that simulates the interaction of the on - axis cosmic rays with the active and passive materials of the instruments.   it has been developed by ifc / cnr milan, southampton university and the international space observatory for particle and photon imaging ( isdc ) in collaboration with the american space institute ( ifc ) and the european space agency ( esi ). using the x - ray transient grs 1124 - 684 ( nova muscae ) as an example  , we have simulated ibis observations of this spectral feature, with exposure times ranging from 125 s to 15,000 s, using as input parameters the values measured by the sigma telescope during its outburst at @xmath0500 kev. the simulations show that the emission feature can be appreciated for observations as short as 500 s. we have also performed simulations with different exposure times and spectral parameters to determine the sensitivity to detect an emission line at@xmath0 500 kev over a continuum.
we investigate the combined effect of external in - plane electric and magnetic field on the magnetism of some monolayer graphene nanoflakes ( nanoflake or quantum dot ).   the influence of both fields on the ground state spin phase diagram of the studied nanostructures is investigated by means of calculations based on the tight binding model with hubbard term ( in mfa ), supplemented with electrostatic potential term and zeeman term. for the first time, we show that the effects of electric field and/or magnetic field can be combined in a single system of interest, where the control over magnetism by electric field was proven in experiment beyond classical semiconducting systems. to obtain the experimental results, we use a bottom - top approach, i.e. a procedure based on some molecular precursors. within this scheme,   two classes of graphene nanographenes ( gnfs ) are studied : one is a triangular shape and the other a hexagonal shape, which are characterized by the presence of edge and further reduction of dimensionality of graphene below two. as a result of the interaction between the two sublattices, the geometry of the nanof lake is changed from a
we study the contributions of different initial state partons to the hard qcd jet cross - sections in hadronic collisions at high energies ( @xmath1 ) using nlo calculations.   the results show that the contributions from the different parton   parton collisions are investigated as a funtion of both @x Math1 and jet rapidity. for the quark   quark(anti)quark scattering process, the relative contributions vary strongly as a function of both@x math1 and rapidity which is explained by the uncertainty on the gluon density at ~2.36 tev. with the same set of parton distribution functions ( pdfs ), the distributions of the jets also depend on the rate of jet production and the speed of the collision. however, the results presented in this note need to be improved using next - to - leading - order calculations because the detailed subprocess calculations in different @x maths1 intervals are still not posiible. moreover, possible systematics from jet fragmentation and the actual reconstruction of jets from the observable mesons and baryons, from hadronization schemes, from diffractive processes and the underlying event structure need further investigation.
supersymmetry @xcite provides us with a stable bridge between the electroweak scale of @xmath5 where laboratory experiments in particle physics are performed, and the grand unification / planck scale of@xmath6 / @x Math7 where all phenomena observed at low energies are expected to be rooted in a fundamental theory including gravity.   this bridge requires a base of high precision experiments from which the extrapolation to the planck Scale can be carried out in a solid way. here   we analyze the threshold analysis of the charged scalar lepton sector of the first and second generation of the supersymmetric model at the electro weakly interacting ( e.g., chargino ) and the neutralino sectors of the third generation by means of one - loop corrections for the on - shell slepton production processes and the quantum gauge couplings at the thresholds @X1 and @xx0. using the continuum method, we have calculated the cross - sections for the off - shell particles including the non - zero width effects and the coulombic sommerfeld rescattering corrections, while in the continuum the Supersymmetric one - loops corrections have been calculated for the sleptons and
the presence of near - infrared h@xmath0 emission from bipolar pre - planetary nebulae ( ppns ) and bipolar planetary nebula ( ngc 2346 ) is now recognized as a reliable indicator of bipolarity.   it is of particular interest to establish whether the spatially distinct waists and lobes of these bipolar planetaries are kinematically distinct as well and, furthermore, whether the kinematics bear evidence of the presence of circumstellar disks and/or high - velocity polar flows. to this end, we have undertaken a program of spectroscopic mapping of near- and mid - infrared hydrogen emission at high spectral resolution from two bipolar ppns and one bipolar nebula using the noao phoenix spectrometer on the 2.1 m telescope at kitt peak, az. for the ppn rafgl 618,   whose bright h @ xm0 emission regions are oriented almost perfectly east - west, parallel to the phoenix slit, we obtained a single spectral image centered on the object. for ngc2346, where the emission is brightest toward the waist of the nebula, we obtain spectral images at selected positions near the waist with spatial sampling approximating the
the moduli space of algebraic curves of genus @xmath9, defined over an algebraically closed field @x math0, is an interesting object that has received plenty of attention since the mid xx - century.   it is an irreducible quasi - projective variety of dimension and understanding the stratification of this space has been also a major problem with many papers written on the subject to this day. in this paper   we review the progress made in the last decade on the problem of automorphism groups of curve of genus@x Math9.
spin polarized trilayer quantum hall ( tlqh ) systems at total filling factor @xmath14 are studied by combining the mutual composite fermion ( mcf ) approach and the composite boson ( cb ) approach developed in @xcite.   the results show that the cb approach is superior to the mcf approach in the study of im - balanced spin - polarized bilayer quantum halls ( blqhs ) with broken symmetry, because the spin sector which displays fractional quantum hall effect and the interlayer phase coherence is explicitly projected out from the lowest landau level ( lll ) and the collective order parameter fluctuations in the pseudo - spin sector are treated on the same footing as the ones in the epqfm approach. using a wavefunction approach,   we also study the quantum phase transitions between different ground states.
the usual contact process is a model for nonequilibrium process composed by two subprocesses : a catalytic creation and a spontaneous annihilation. in the present work,   we study conservative versions of the usual contact processes using a constant - density ensemble.   the conservative versions are models that allow us to study the model without the danger of falling down into the absorbing state. as a result  , they are equivalent, in the thermodynamic limit, to the ordinary models.
magnetic monopoles are particles carrying a quantized magnetic charge and are predicted in various theories.   the existence of magnetic monopoles implies that both electric charge and the hypothetical magnetic charge, given that the associated electromagnetic fields still satisfy maxwell s equations, are quantized. since they are stable, they should still be present in cosmic rays. however, there is no experimental proof for their existence. here   we present the results of a search for non - relativistic magnetic monopole which would catalyze the proton decays via the rubakov - callan effect in icecube. using the icecube neutrino observatory at the geographic south pole of the university of california, los angeles, we show that the most likely location of these monopoles is in the antartic ice detector @xmath0 of the in - ice detector, which is used as a detection medium for the cherenkov light from electrically charged secondary particles produced when high - energy astrophysical neutrinos interact in the surrounding matter @xcite. by using a combination of density functional theory and quantum mechanical calculations, we find that the number of monopoles in the detector medium can be estimated to be about
the @xmath0 transition in the medium is investigated using the potential model.   the model which is free of drawbacks given above has been proposed ( model * b * in the notations of present paper ), but the consideration was schematic since our concern was only with the role of the final state absorption in principle. for the lower limit on the free - space @x Math0 oscillation time the range of uncertainty is too wide ( see eq. 2 ). to reduce the uncertainty the model with bare propagator   is considered and the corrections to the models are studied in detail.
we report the detailed experimental investigation and the corresponding theoretical analysis of electromagnetically induced transparency and dark fluorescence in a cascade three - level diatomic lithium in an inhomogeneously broadened environment.   we have incorporated the effect of the magnetic sublevel ( m ) degeneracy of the rotational levels in the lineshape analysis and report @xmath6-dependent Lineshape splitting.    we show that the coherence is remarkably preserved even when the coupling field was detuned far from the resonance.. the open property of molecular systems will be discussed in our theoretical calculation., we also demonstrate that the coupling laser field dependent splitting of the upper level can be used as a new method for measuring the molecular transition dipole moment matrix element  @xcite.
the origin of lepton mixing is one of the most important open questions in particle physics.   the experimentally observed @xmath2 mixing angle opens the gateway to access two remaining unknown parameters in the neutrino sector : the neutrino mass hierarchy and the leptonic dirac cp phase. if neutrinos are majorana particles, there are two additional majorana cp phases which can play a critical role in the neutral neutrinoless double beta decay, and we know nothing about their values so far. here   we review the recent advances in our understanding of the origin of flavor mixing from cp symmetry.
quantum entanglement provides a valuable resource for many important applications in quantum communication, quantum computation and quantum metrology.   recently, frwis and dr reported the experimental realization of a class of quantum entangled state which shows similar feature as the greenberger - horne - zeilinger ( ghz ) state, but it is more robust than the normal ghz state in a noisy environment. in this paper, we discuss one of the most important two - qubit measurement, say the bell - state measurement @xcite. here, we describe the logic bell -State analysis ( lbsa ) for distinguishing the concatenated ghz ( c - ghz)state of the form @xmath0 from the other four logic bell states with the help of controlled - not gate. moreover, we show that the approach for lbsa can also be extended to distinguish the c -ghz state with arbitrary logic qubits.
the solar neutrino oscillations are the most important evidence for the existence of massless neutrinos in the standard model of particle physics.   the main evidence for these oscillations comes from the angular dependent flux of atmospheric muon - type neutrines measured at superkamiokande @xcite, combined with a large deviation of the muon- to electron - type neutron flux ratio from theoretical predictions. here   we review the case of a set of high energy ( @xmath8  gev ) electrons produced in the solar core and propagating in constant electron number densities ( ~3 g/@xmath9 ), and the effects of matter interactions on the event rates of this species are discussed. by taking into account the fact that the experimentally measured events are very different from those predicted by theoretical predictions, it is possible to assume that the observed event rates are due to the mixing of three flavour eigenstates of the same eigenstate, or to the formation of a linear combination of the other two flavours of the eigen states. as a result, the rate constants of the observed events are well within the range of the expected event rates for each of the three flavour
spatio - temporal recordings of neuronal activity are ubiquitous in many scientific disciplines and often exhibit well - defined patterns of propagation where some prominent feature first appears at a specific location and then spreads to other areas until potentially becoming a global event.   the question arises naturally whether these patterns show any consistency, i.e., to what extent do the spike trains that consistently lead global events and are there other spikes trains that invariably follow these leaders?   we introduce a new framework consisting of two directional measures ( spike - order and spike train order ) that allows to define a value termed _ synfire indicator _ which quantifies the consistency of the leader - follower relationships. for a perfect synfire pattern in which all neurons fire repeatedly in a consistent order from leader to follower,   this synfire indicators attains its maximal value of @xmath0. using an artificially generated spike train set we demonstrate the new approach using artificially generated datasets before we apply it to analyze the consistency between propagation patterns in two real datasets from very different fields of research, neuroscience and climatology : giant depolarized potentials recorded from mice brain slices and giant excitatory / inhibitory waves recorded from a mouse brain slice dataset.
super - eddington accreting massive black holes ( seambhs ) are rare objects that are found in narrow - line seyfert 1 galaxies ( nls1s ).   we have initiated a large reverberation mapping ( rm ) campaign to measure the black hole mass of these objects using resonant resonance spectroscopy. here  , we present new data on the time lags of the optical and uv fe ii  emission lines in five extreme seambh candidates from our sample of such sources. for each source, we find a significant time lag relative to the continuum in the range 40005400   ( h@xmath0 ) and a weak time lag in the ranges 280035000   and 20002600  years.. the time lag is consistent with the one of the strongest fe ii lines observed in @xcite and is related to the size - luminosity relation between the broad - line region ( blr ) and the central accretion disk ; however, the location of the fe ii - emitting gas in the blr is not well understood. at the same time, we show that the bh mass of the super -Eddington
we study the effect of frustration on the ground state magnetic order of the mixed layer pnictide oxides.   we develop a simple model of classical heisenberg spins with nearest neighbor intra- and interlayer interactions in the form of a bilayer model based on a set of two layers, one each of type mn(1 ) and @xmath15. for each layer,   the lattice constant is a function of the number of spins in the mn ( 1 ) layer and the size of the neighboring layers. to study the influence of frustrated interlayer coupling on the ordered phase of the system, we investigate the effects of the monte carlo model on the symmetry of the interlayer interaction strengths and the orthogonal magnetic structure observed in the plane - oriented mixed layer antiferromagnets @xcite and@xmath6.. the results show that frustration leads to a strong loss of c - axis order in both layers, which is due to the formation of a non - collinear nel ordered state in the center of the second layer. however, the temperature at which the layers order suggests that the system is actually composed of two independent nelordered layers.
the study of resonance state of the neutron - unbound nucleus @xmath0be is a challenging problem as it has no ground state and its two - body potential is a shallow well followed by a very low wide barrier. in the present work  , we resort to a very effective technique used earlier by us for study of weakly bound nuclear systems  @xcite.   the theoretical procedure of supersymmetric quantum mechanics ( sqm ) is adopted to tackle the resonance states of unbound nuclei like @x Math0be. using this technique,   we have been able to reproduce the unbound state energy without any modification in our constructed microscopic potential.
vibrational excitations in disordered structures are an active field of investigation by different methods.   the main purpose of this paper is to give a mean - field description of vector vibrational models, namely : ( i ) to derive the coherent potential equations for vector vibrations in dis ordered lattices with force - constant disorder ; ( ii ) to solve them analytically in limiting cases and numerically through the whole energy range ; ( iii ) to apply the solution to investigate the scattering properties of external plane - wave vibrational excitation and, in particular, the ioffe - regel crossover from a weak- to strong - scattering regime ; ( iv ) to demonstrate the importance of sum - rule correlations in the dynamical matrix for scattering property of vibrational external plane waves ; and ( v ) to compare the vibrational problem with the electronic one.
we show that the cosmological redshift of a universe with flat space sections ( i.e. with @xmath1 ) can not be explained as a pure doppler effect due to motion of galaxies in a non - expanding flat space.   instead, we show that it is the curvature of the spacetime that makes the observed redshift and distance between galaxies in an expanding universe different from those in a flattened space. this is a reflection of the fact that newtonian and general - relativistic cosmology of an isotropic and homogenous universe are equivalent only if one does not consider the propagation of light.
most modern speaker recognition systems are based on human - crafted acoustic features.   a problem of the mel frequency cepstral coefficients ( mfcc ) is that it involves plethora information besides the speaker identity, such as phone content, channels, noises, etc. in the famous gaussian mixture model - universal background model ( gmm - ubm ) framework  , the acoustic space is divided into subspaces in the form of gaussian components, and each subspace roughly represents a phone. by formulating the speaker recognition task as subtasks on the phone subsp spaces,   the gmm-ubm model can largely eliminate the impact of phone content and other acoustic factors.    this paper follows the work in  @xcite and provides two enhancements for the deep neural network ( dnn)-based feature learning : first, phone posteriors are involved in the dnn input so that speaker - discriminative features can be learned easier by alleviating the effect of phone variation ; second, two scoring methods that consider the temporal constraint are proposed : segmentation pooling and dynamic time warping ( dtw ).. the new methods are proposed in section   and the
the coupling between graphene plasmons and substrate surface plasms in a structure with a heavily - doped substrate and with / without a metallic top gate is studied theoretically.   the effect of the doping concentration, the thickness of graphene - to - substrate separation, and the plasmon wavenumber on the coupling is studied. for the ungated structure,   an increase in the damping rate close to @xmath6 s@xmath5 at room temperature in disorder - free graphene suffered only from acoustic - phonon scattering, whereas the coupling in the gated structure is more effective due to the gate screening. in structures having different dielectric layers between the top gate, graphene layer, and substrate, the coupling can be less effective as the graphene layer is separated from the substrate by a thin layer of graphene. in the case of substrates with a metal top gate ( e.g., p@x math7-si ), the couplings are more effective in the presence of graphene than in the absence of it. in order to study the influence of the carrier scattering in the substrate, we derive a dispersion equation of the coupled modes of graphene and substrate surfaces in the heavily -
the central black hole ( bh ) of a satellite galaxy likely wanders in the halo of its host galaxy after a galaxy merging event, before it finally sinks towards the center of the host galaxy due to the dynamical friction.   if we really discover a massive bh wandering in a galactic halo, it indicates that many such wandering bhs, the remnants of satellite galaxies, in distant galaxies are missing due solely to sensitivity limits of current instruments. in this letter  , we determine the most efficient waveband(s ) to detect a wanderingmassive bh of the satellite galaxy in the m31 halo and present the expected emission from the wandering bh and from an assembly of stars bound by the bh. as a case study, we focus on the nearby galaxy m31 ( andromeda galaxy ), which is in the process of a collision with another galaxy at a distance of 780kpc. using @xmath7-body simulations, we establish the probable position of the associated wandering massive bH by performing a detailed x - ray spectral analysis of the faint a low - luminous emission from both the wandering Bh and the cluster of stars around it. since all massive bhs so far
the exclusive production of @xmath0 meson in proton - proton collisions was intensively studied close to its production threshold at the cosy ring at kfa jlich@xcite and at saclay @xcite. here   i present results obtained in the formalism with unintegrated gluon distribution functions for the same exclusive channel but at much larger energies ( @x Math9 10 gev ).   the dominant mechanism may be expected to be the diffractive mechanism.
non - thermal phenomena in the intra - cluster medium ( icm ) have been detected in a number of clusters of galaxies.   the interpretation of these fluxes is still not yet settled, nor are the different classes of diffuse radio emission completely understood. here   we give an overview on current interpretations and theories, and outline the physical insight we will gain from understanding the currently strongly increasing number of non - thermal detections of galaxy clusters.
the state - of - the - art c - ran technology is able to support thousands of remote radio heads ( rrhs ).   full - scale rrh coordination over such a large network involves prohibitively high computational complexity, which implies that the detection complexity quickly becomes unaffordable as the network size grows. in this paper, we propose a perfectly scalable algorithm for joint signal detection in the uplink of c-ran using channel sparsification and message - passing algorithms. with the sparsified channel matrix,   the computational complexity of minimum mean square error ( mmse ) detection is reduced from @xmath0 to@xmath1, where the total number of rrh nodes and the number of messages per rrh is a constant depending on the computing implementations. however, the algorithm is not perfectly scalable yet, in the sense that the computation complexity grows faster than linear with the networksize. here  , we show that the proposed algorithm can be used to improve the convergence of message passing over a bipartite random geometric graph over a low - complexity iterative solution to inference over random sparse graphs.
the optimal state estimation of a single quantum bit ( qubit ) is the topic of this article.   it is shown that the optimal estimation of the single qubit can be obtained simply by using the no - signaling principle. for any figure of merit, the guessing - probability ( distributions ) have the same form, @xmath1. here   @x math2 is constants and @x maths3 is the angle between the bloch vector of the prepared qubit and that of the guessed one.    the results show that the maximum average fidelity for a single qubits estimation is @x Math0.  in addition, the optimal measurements are the same for all figures of merit.
the decay of quantum turbulence at low temperatures is expected to be due to the kelvin - wave cascade that works on length scales smaller than the intervortex distance.   it is expected that this cascade pushes the energy down to the scales of order the vortex core where it can be dissipated due to phonons. here   we show that the spectrum depends only weakly on mutual friction in the limit @xmath2.
fractal fluctuation in many natural and artificial phenomena is characterized by the so - called singularity spectrum of some numerical or experimental data. to understand the dynamics underlying the fractal, it is not uncommon that multiple data capturing different aspects of the phenomenon of interest are used in the analysis. for fractal analysis on natural objects,   multiple data cross examination may provide the chance to examine the potential link of fractal fluctuations in the data.   in particular, one would suspect some degree of  fractal correlation  in the Data if the fractals generating mechanisms associated with the data source are coupled together.. essential to the notion of fractally correlated data is the distinguishability of singularity spectra. here  , we introduce a mutual multifractal analysis based on the joint partition function analysis ( jpfa ) which can be applied to the analysis of multinomial processes generated by multi - dimensional cascades of more than one variable. using this approach, we show that the two most important variables in the single - dimensional cascade are the same as those in the multi - dimensionality cascade, and that the results obtained from the previous studies are consistent with the assumption of discrete scale invariance of the multin
we have developed a new time - to - digital converter ( tdc ) core for the @xcite@xcite particle accelerator.   the core is based on a look - up table ( lut ) that generates timestamps of the incoming signal using a tapped delay line and a coarse counter, which is sampled by d flip - flops. in order to calibrate the system clock, the delay line is subject to process, temperature and voltage induced variations, and it needs to be calibrated against them. here  , we describe the design of a new process for startup calibration of the tdc core.the core is available under the lgpl free software license and its full vhdl code can be freely downloaded from http://www.ohwr.org/projects/tdc-core.
the problem of generating majorana neutrino mass and transition magnetic moments in the minimal supersymmetric standard model ( mssm ) violating @xmath0-parity violating supersymmetry breaking has been widely discussed in the literature.   many older approaches used certain simplifying assumptions about the low - energy mass spectrum of the Mssm model, which have been corrected by the use of grand unification conditions and renormalization group equations ( rge ) @xcite. in this paper   we present detailed calculations performed assuming the gauge mediated supers asymmetry breaking mechanism, for the whole allowed parameter space. to our best knowledge  , all calculations made so far used the supergravity mechanism of supersymmetrized breaking. however, it is not known how the gauge couplings unify at the energy@xmath1 gev, which is not true in the ordinary standard model. in order to address this question we propose a new model, based on the principle that the gauge coupling between the two quantum gravity gauge pairs unifies at the same energy as the energy, but with a different number of degrees of freedom of each gauge pair. using the proposed model, we show that the density of the
quantum chaos began as an attempt to find chaos, in the sense of extreme sensitivity to changes in initial conditions, in quantum mechanical systems.   the most natural guess would be that chaos would appear in the quantum realm in much the same way as it appears in the classical one, namely in the form of sensitive dependence on initial conditions. however, the laws of quantum mechanics do not permit a similar definition, since the laws do not show an exponential sensitivity to the initial conditions.in this work, we explore whether the onset of chaos can also take place in spin-1/2 systems if one includes also the dzyaloshinskii - moriya ( dm ) interaction. using exact diagonalization  , we find that the ising and xxz models can develop chaos, but the same does not apply to the other two models. for all values of the anisotropy parameter, the level spacing distribution for the integrable xxz chain is poissonian@xcite, except for some special ones that may lead to excessive degeneracies. by contrast, for the integration of the effective in - plane dm term into the 1d heisenberg model, the effects of the dm
in ultrarelativistic nuclear collisions the deconfined state of colour charges is created shortly after the initial impact.   then, the subsequent expansion and cooling is rather fast. in this paper   i argue that one such scenario which could be realized is that the fireball matter violently decays into many smaller fragments or droplets @xcite. in order to test various observables that can be sensitive to the production of hadrons from droplets a monte carlo model called droplet an hadron generator for nuclear collisions ( dragon )   has been constructed. at collision energies above few tens of gev per nucleon the baryochemical potential is so low that a first order phase transition appears highly unlikely and we rather see a smooth crossover. however, it has been noted recently that the bulk viscosity has a sharp peak at @xmath2 as a function of temperature@xmath3. based on this observation it has also been proposed that the fragmentation of the fireball at @Xmath2 is a realistic scenario at any ultrarelateivistic collision energy.
we study the statistical properties of the conductance through a quantum - chaotic dot with a superconducting lead attached to it.   we take into account the presence of a schottky barrier  which is formed in real normal - metal  superconductor ( ns ) junctions of transparency @xmath0 in the super Conducting lead. using a scattering approach to the problem of quantum transport and random matrix theory ( rmt )  , we calculate the complete distribution of conductances for different values of @x Math0. as we will see, the conduction distribution is affected by the presence or absence of thesuperconducting region as well as the scattering at the schottkiy barrier.
the disordering transition in a two - layer @xmath3 heisenberg antiferromagnet is studied in detail.   the model describes two weakly interacting 2d heisenburg antiferromeagnets, each of which is ordered at@xmath0 and possesses goldstone excitations related to a spontaneous breakdown of a rotational symmetry. for small @x Math6,   one should expect a disordering phase transition at some critical ratio of @x math6. here   we focus on the properties of the system at @xMath0, and on the corrections to scaling at finite @x maths13.. the key issue we want to address at @Xm0 is the applicability of perturbative and self - consistent spin - wave approaches.    we show that the spin - waves are not sufficiently accurate for a single - layer system, and that the contributions from longitudinal fluctuations to the @xmatrix expansion are substantial, which makes the @ xm25 expansion inapplicable. however, as the lattice constant decreases, the quantum monte - carlo approximation becomes more and more reliable, and at vanishing @x mathematics, the calculation of the
we investigate the crossover from quasi one dimensional system to quasi two dimensional ones in a cold atom system with one dimension spin - orbit coupling ( soc ).   we show that the topological fulde - ferrell - larkin - ovchinnikov ( fflo ) state is favoured in this system with nontrivial topology @xcite, and that the crossover can be achieved by tuning the tunneling strength of the nearest tube. using two coupled tubes model, we analyze the phase transition point between topological fflo state and normal f flo state, where topological properties can be verified by the presence of majorana edge modes. for quasi two-dimensional system, we find the system supports novel gapless superfluid phases which can be classified by the number of gapless points in the excitation spectra. the influence of transverse zeeman field, interaction strength, and tunneling between nearest tubes on these novel phases are also studied.
radio lobes are the faintest and most difficult regions to detect in active galactic nuclei ( agns ).   x - ray studies of radio lobes have opened a new field of research and in particular have allowed the first checks on the assumption of minimum energy condition in the lobe ( equipartition ). here   we present a new study of the spatial distribution of the inverse compton magnetic field and particle densities in the lobes of the @xmath4 kpc radio galaxy, which is located at the edge of the active galactic nucleus. using the chandra and xmm - newton observatories, we show that the average magnetic field density in the radio Lobes is significantly higher than that in the surrounding space.    the results indicate an enhancement of the magnetic energy density towards the edges of the radio lobers. for the first time   it is shown that the observed enhancement is not due to thermal bremsstrahlung, but to the interaction between electrons and nuclear photons.
we review several models of bursting behavior in hydrodynamical systems using ideas from dynamical systems theory and then describe a new mechanism for the bursting behavior observed in experiments on convection in @xmath0he/@xmath1he mixtures by sullivan & ahlers   ( 2015 ).   this mechanism ope - rates naturally in systems with broken d@x Math2 symmetry undergoing a hopf bifurcation from a trivial state, i.e., when the system is in a turbulent boundary layer that is characterized by bursts of low speed streamwise " streaks " of flowing fluid. here   we discuss the results of an extended version of the model developed by moehlis & knobloch   @xcite ( 2014 ) which provides an explanation for the observed burst behavior in these systems.
we propose a stochastic online control scheme for energy harvesting ( eh)-powered multi - hop wireless networks with imperfect batteries.   the proposed scheme is based on a data - backpressure based scheduling and degenerated energy - queue based power allocation scheme that can maximize the utility of data rates for eh multi - hops wireless networks, without requiring any statistical knowledge of the stochastically channel, data - traffic, and eh processes. by integrating and generalizing the lyapunov optimization techniques in @xcite, we re - establish a systematic framework to develop and analyze the sto Choreogrouping and Optimization schemes for eh wireless networks using finite battery capacities and/or energy dissipation over time. as a proof of concept, we consider a practical battery model accounting for finite battery capacity, energy ( dis-)charging loss, and energy dissociation over time and apply the sample path analysis in@xcite to derive the conditions that the proposed algorithm is feasible for any given finite batterycapacity without eh admission, which can help fully exploit the available harvested energy. under these conditions, we rigorously establish the performance guarantees of the proposed strategy in form of sub - optimality bounds in the presence of practical battery imperfections.
epidemic spreading on complex networks has attracted much attention in the past decade.   however, the control of epidemic spreading by routing strategies has received little attention. in this paper, we consider an efficient routing strategy proposed by yan @xmath0  @xmath1  @xcite to study how the efficient routing protocol affects traffic - driven epidemic spreading. for each node in a network,   each node is assigned a weight that is proportional to the power of its degree, and the efficient path between any two nodes is corresponding to the route that makes the sum of the nodes weight ( along the path ) minimal. using the efficiency routing protocol, we find that the epidemic spreading can be effectively controlled by the optimal value of @x Math6, leading to the maximal epidemic threshold.
the phase structure of qcd is relevant in the description of various phenomena : from subtle modifications of the cross - sections in high energy collisions of nuclei to exotic states of nuclear matter in neutron stars.   even though we have a good understanding of how to perform simulations at zero baryon density and finite temperature, the simulation with non - zero chemical potential has been problematic. to deal with the complex phase that the chemical potential introduces to the fermion determinant,   a number of techniques have been proposed : various reweighting methods, imaginary chemical potential, etc. here   we present here an approach based on the canonical partition function which alleviates the sign problem, the overlap problem and the determinant fluctuation problems.
doped perovskite manganates are a family of materials with large magnetoresistance ( mr ) at room temperature in the range of tens to hundreds of oe.   this effect is due to the simultaneous onset of metallic conductivity and ferromagnetism as doping concentration @xmath5 is increased across the insulator - metal transition point of @xcite. for magnetic field - sensing applications,   low - field responsivity is necessary, since the cmr effect observed in the generic doped manganate perov Skites involves a magnetic field above 1 tesla @xcide, and the low - fields are minimal in the field range of 10 - 100oe. here   we study the spin - dependent transport of ferromagnetic polarons across a grain - boundary - originated tunneling barrier between two cmr electrodes in the region@xmath3ca@x Math4mno@x math2 in the doping range of @x maths2.1 - 3.0 using a combination of experimental and theoretical calculations.    the results show that the ferrommagnetic conductivity of the surface of the interface is strongly influenced by the size of the
the in - plane resistivity and magnetization of ptbi@xmath0 superconductor ( ts)@xcite have been measured at 2 k, the lowest temperature studied in this work.   the intra - plane and inter - plane magnetization displays pronounced anisotropy, being diamagnetic with field aligned along the plane and paramagnetic when field is perpendicular to the plane.. the magnetoresistance ( mr ) and hall resistivity ( h ) show two types of carriers, namely, magnetic and non - magnetic.
the dynamics of domain coarsening in a driven system, @xcite, is studied.   the domains are characterized by a single length scale, @xmath0, that grows according to a power - law. for systems with a conserved order parameter, the growth exponents for the domains that are growing are @x Math1 for both potential and nonpotential versions of the swift - hohenberg equation. for cases where the order parameter is not conserved, the exponents are usually found to be @x math2. here  , we show that the growth exponent for a system with a uniform pattern of stripes is different from that for a given set of stripes in that the initial and final states are not thermodynamic equilibrium states but are steady - states of the system. this difference is explained by the fact that the wavelength of the pattern and the scale of the domain are independent of the local wavenumber. when the domain size is measured experimentally, the results are consistent with the results of theoretical studies of the scaling of the structure factor of the fast - growing system,@xcite.
we have been studying the ` felobal'qsos @xcite for two reasons.   first, their uv absorption troughs are unambiguous signatures of radiatively driven outflows powered by an accretion disk - like galaxy ( agn ) and second, they are invariably reddened and have high ir luminosities. in this study   we compare the strength of their outflows to the luminosity of obscured star formation in their host galaxies as measured from optical through far - ir photometry.we find that all 31 of our sample have total ir lumosities in excess of @xmath0l@xmath1, with nine objects exceeding @x Math11l@Xmath1.    the dominant power source is usually an agn. a pure agn is either the most likely power source, or consistent within the 90% confidence interval, for ~50% of the objects observed at high redshifts.the results are consistent with the model predictions of quasar mode feedback.
the sloan digital sky survey ( sdss ) is revolutionizing studies of the galactic halo because it is providing homogeneous and deep multi - band photometry in five passbands.   the quest survey is the largest such survey that is capable of discovering rr lyrae stars in the outer halo. here   we use sdss imaging data which are part of the sdss data release 1 ( abazajian et al., 2003, dr1 ) to design optimal selection criteria based on sdss colors for a complete sample of rrLyrae star candidates. using a single - epoch of sdss image data, we select and analyze candidate rrlyrae Stars from the search for clumps and streams in the galaxy halo by comparing their spectral characteristics with those of other rr Lyraestars discovered by the quest surveys.    we find that the sd ss colors of rrs can be used to select rr lee stars efficiently and robustly, and that the selection criteria are consistent with the hierarchical models of galaxy formation.
we study the construction of mutually unbiased ( mu ) bases of the space @xmath7 in dimension six or any other dimension.   we do so by directly exploring the unitary matrices  randomly distributed, but according to the haar measure  whose columns vectors constitute the bases elements, which must fulfill a series of requirements concerning their concomitant bases being unbiased. for each dimension, we perform a two - fold search employing i ) an amoeba optimization procedure, where the optimal value is obtained at the risk of falling into a local minimum and ii ) the so called simulated annealing @xcite well - known search method, a monte carlo method, inspired by the cooling processes of molten metals.the overall scenario reduces to a simple though a bit involved optimization procedure. in point of fact  , we can be absolutely confident about the final result reached since the second recipe contains a mechanism that allows a local search that eventually can escape from local optima.
noncommutative theories have been discussed in the literature by a large number of authors, mainly due to the discovery of their relation to string theory @xcite.   the inherent nonlocality of these theories leads to the surprising mixture between ultraviolet ( uv ) and infrared ( ir ) divergences which could break the perturbative expansion. to avoid difficulties with the uv / ir mixing,   a new approach was developed in@xcite for the nonrelativistic scalar field theory based on the coherent state approach. in this approach, instead of moyal product approach, the free propagators acquire a gaussian damping factor, which incorporates @xmath0 as a natural cutoff at large momenta. here   we show that up to the one - loop order the scattering amplitude is ultraviolet finite on a quantum plane at the same time, but the amplitude involves logarithmic singularities as the non commutative parameter tends to zero. to eliminate them  , it is necessary to include a quartic self - interaction for the scalar fields.
we have conducted a systematic survey of da white dwarfs using the last published version of the catalog of spectroscopically identified white dwarf objects from mccook & sion ( 1999 ).   we have obtained optical spectra of all the stars in this collection down to a limiting visual magnitude of @xmath0=17.5 and have compared our results to those of the sloan digital sky survey ( sdss ), which has a very large overlap with our own sample of stars. as a result  , we have been able to obtain a much higher quality sample of data than the sdss due to the fact that we observe one star at a time and adjust our exposure times to obtain spectra with a minimum signal - to - noise ratio ( s / n ) of approximately 50. here, we describe our survey and examine some of the ensemble properties of our current sample. also, we look at a few choice subsamples of objects, including the dao white dwarf, the zz ceti instability strip, and the da+dm binaries. finally, we will look at one specific object, cbs 229, which we believe to be a binary system with a magnetic component.
active galactic nuclei ( agn ) have been detected in the starburst galaxy ngc 253 and the seyfert 2 galaxies ngc 1068 and ngc 4945.   it is generally agreed that low - frequency ( radio ) emission from relativistic jets in agn is synchrotron emission from nonthermal electrons, but it is still debated whether the high -frequency ( x - ray & @xmath0-ray ) emission is due solely to compton scattering by the electrons responsible for the low - frequencies or due to hadronic processes resulting from protons being co - accelerated with the electrons. here  , we develop a semi - analytic model for cosmic ray interactions for the starbursts galaxy m82 ( *?????   * hereafter yegz ) and test its applicability to the presence of agn. using our model, we obtain a best - fit model which accurately reproduces both radio and @x Math0-rays spectra within the confines of the observed properties of the interstellar medium ( ism ) and surrounding radiation field. additionally, we make a prediction of the neutrino fluxes from both galaxies.
the fan observatory bench optical spectrograph ( fobos ) is a fiber - fed, bench - mounted instrument for moderate - resolution radial velocity surveys of bright stars in the northern hemisphere.   the instrument was designed to provide moderate resolution spectroscopy for the grid giant star survey ( ggss ) for the nasa space interferometry mission ( sim ), which requires spectroscopic study of several thousand bright ( @xmath613.5 ) k giants evenly spaced about the sky. during its first light in september 2003,   fobos achieved a signal to noise ratio of 1.0    0.1 with a total of 10,000 exposures at a wavelength range of 4700  nm and a radial velocity of 10 km sec@xmath2. as part of the project to obtain data from the northward-facing axis of the fobos, the instrument has also been used to conduct a series of studies of the galactic dynamics of the supernovae that are likely to be involved in the evolution of the solar system. here  , we discuss the philosophy, hardware specifications and goals, overall design, construction, and performance of fobos and give a brief overview
the identification of a pressure induced iron high - to - low spin transition in ferropericlase and ferrosilicate perovskite, the two major minerals in earth s lower mantle, has stimulated investigations on several aspects of this transition @xcite.   however, there are many open questions that still need to be addressed, in order to understand the implications of the spin transition for the geophysical properties of those minerals. here  , we present a theoretical investigation that explores some of those questions, considering the case of an isolated iron atom in magnesium oxide. using the all - electron full - potential linearized augmented plane wave method, we computed the structural, electronic, and magnetic properties of iron in several charge states, and the respective electric and magnetic hyperfine splitting parameters of active centers. by applying the generalized gradient approximation plus the on - site hubbard correction in the 3d - related iron states,   we show that the energy levels of the iron - related electronic energy levels are generally higher in the high spin ( hs ) state than in the low spin ( ls ) state, with the latter being more energetically favorable at higher pressures.    we then investigate the pressure effects on
the infalling disklike envelopes are common structures around embedded young stars.   they are expected to play a crucial role in the formation processes of stars as well as their surrounding rotationally - supported disks. in this paper  , we examine the gravitational collapse of prolate cloud cores with slow rotation by means of numerical hydrodynamics and show that both the infalling disclike envelope and the rotational - supported circumstellar disk are natural outcome of the gravitational contraction of a _ prolate _ cloud core. using a model of an isothermal cylindrical cloud in hydrostatic equilibrium in the radial direction and that the cloud is rotating around the cylinder axis,   we show that the gravitational compression of the cloud core leads to the formation of a highly disklike envelope which has a size of @xmath3 au, which is an order of magnitude larger in size than a rotationally-supported circumstellar Disk observed in the dust emission. on the basis of our results, we propose a mechanism for the evolution of such infalling envelopes.
complex perovskites form vast and promising group of compounds for microelectronics, yet many features they show are still a battlefield for scientists. among the compounds with a well - known general formula @xmath4 one can find a spectrum of cases, from relaxor ferroelectrics ( like _ pmn _ and _ pst _ ) to antiferroelectrics ( like  pmw  and  pmr  ).   the present work is aimed on suggestion of a new approach to raman spectra of @x Math9 complex perov Skites.. diagonal and parallel raman Spectra of _ pmm_ and  pst_ crystals were measured with _   x _, _ y _ and  z _ being along the fourfold cubic axes. in this paper   only reduced rama spectra are discussed, so the word  spectrum  is actually for  reduced spectrum  unless specially stated.    the author deliberately tries to avoid using appropriate mode identifications when speaking of some part of a spectrum as a whole or a given part of the spectrum. by doing so   it is possible to make a more accurate line assignment of the raman spectrum of
we show that a particle s quantum mechanics wave function and its derivatives can be defined independent of space - time coordinate systems.   the differentials are obtained from a trans - coordinate limiting process that allows a dynamic principle to be applied everywhere within a free particle s wave packet. in order to preserve invariance, the influence of the collapse of a wave function is transmitted through invariant metric space over the surface of the backward time cone of the initiating event ( such as a measurement event ) in the manner described by hellwig and kraus . here   we show that the original h - k collapse leads to troublesome causal loops, but this objection is not valid if a _ modified _ hellwig - krau collapse is adopted that makes use of the trans - coordinates. when that is done it is shown that absolute causal priorities overcome the a - causal objections to a h-k collapse.
cyg x-1 is a black hole that has been the focus of much research in the field of black hole physics for decades.   it is well - known that the low state spectrum of cygx-1 shows a weak soft component, with a photon index of @xmath0, and that the soft components are weak compared to the power - law. here   we show that the observed soft flux is due to reflection from the optically thin outer disk, not to intrinsic disk emission. using a combination of fourier transform and cross - power density measurements, we find that the time lag of the soft photons behind the hard photons is a function of the energy spectrum of the seed photons, the corona temperature, the optical depth, and the mean free scattering path. by combining these data with the spectra of other black holes, we demonstrate that the transition from hard to soft x - ray emission is caused by a process involving the interaction of the two states of cygnus x- 1 with the outer disk.    we also show that this process is independent of the spin - dependent phase delay of the cross power density, which is explained by thermal disturbances propagating from the edge of the
phylogenetic trees ( evolutionary trees ) are widely used in evolutionary biology to represent the tree - like evolution of a collection of extant species.   however, due to reticulation events, such as hybridization and lateral gene transfer ( lgt ) in evolution, phylogenetic trees representing the evolutionary history of different parts of the genomes found in the same collection of the extant species may differ. for the study of the maximum agreement forest ( maf ) problem,   several metrics have been proposed in the literature, including robinson - foulds distance, nni ( nearest neighbor interchange ) distance, tbr ( tree bisection and reconnection)distance, spr ( subtree prune and regraft ) distance ; and hybridization number ( i.e., the number of hybridization events needed to transform between the two trees ). in this paper, we propose a new metric, the rspr distance, which is the order of the rooted version of the maf minus @xmath4. using this metric, we construct a phylogenetic tree for each part of the genome found in all the species in the collection of species and compare these different trees simultaneously. by using the rSpr distance as a lower
we discuss the problem of quark mass spectrum and mixing angles by making extensive use of a democratic structure for the mass matrices ( dmm ).   we found that this approach is a particularly convenient choice, because it raises quite naturally in brane picture, and it can adequately generate both quark masses spectrum and cabibbo - kobayashi - maskawa ( ckm ) matrix to the precision determined by current experimental data. using the dmm approach, we show that the fermion localization mechanism can be used to localize fermions in an arbitrary position along the extra dimension, while breaking the family symmetry by modifying the detailed shapes of their wavefuctions. as a result, we obtain a non - trivial solution for the kaluza - klein ( kk ) zero - mode wavefunction along the fifth dimension, which is related to the quark spectra and the ckm matrix.
ngc  3109 ( ddo  236 ) is a late - type dwarf spiral galaxy.   it is well resolved into stars and is one of the largest magellanic dwarfs close to the local group at a distance of 1.36@xmath80.10  mpc with an apparent major - axis diameter of 30  ( 12  kpc ) and minor - axis size of 6  ( 6  cm2 ). in this article   we derive the x - ray population in the field of ngc 3109 from the _ rosat pspc _ observations. using three detection procedures we find two candidate agn which are found to coincide with the extent of the high - energy ( hi ) envelope around ngc ’s nucleus. these two agn are used to study the gas content of the galaxy.
in recent years, there has been considerable progress in elucidating the construction of bulk gravity observables in the dual cft language.   some surprising phenomena have been found, particularly in situations involving causal horizons in the bulk. in particular, contradictions appear to arise between the existence of linear operators associated to bulk observables behind horizons and the semiclassical analysis around the expected smooth spacetimes. a paradigmatic example is the information paradox of black hole evaporation ( @xcite ), which is shown to arise when considering semiclassically distinct configurations, rather than in perturbation theory around a fixed background. in this work,   i investigate the relation between the bulk hartle - hawking wavefunction of the effective bulk physics and the dual qft states by investigating the relationship between the hilbert spaces of uv theories and the density functional theory of quantum gravity. using the hartling - schwarzschild formalism  , i argue that such observables are not non - perturbatively diffeomorphism invariant, and that they fail to obey certain non -perturbative consistency conditions analogous to the wheeler - dewitt equation that implements the ham
we introduce a new notion of gauss diagrams of  3-manifolds, which appears to be a simple combinatorial way to describe oriented manifolds with boundary.   we show that the heegaard splitting of a closed orientable manifold can be reconstructed from it by gluing 2-handles along the curves of the handlebodies and filling in 3-balls. using this construction, we show how to compute the fundamental group and the first homology group of a manifold directly from a gauss diagram, and how to distinguish homology spheres.
recent advances in optical space telescope imaging have enabled the study of the star formation history of our own and Andromeda ( m31 ) and other galaxies in the local group.   the supernova acceleration probe ( snap ) and the terrestrial planet finder ( tpf ) will provide a major advance in this field by providing direct age diagnostics via main sequence ( ms ) photometry, sampling at a @xmath020% fill factor.
a soft wall holographical model that describes hadronic spectra with an arbitrary number of constituents was proposed.   the model is based on the ads / cft idea, and it allows us to obtain hadronic spectrum with regge behavior, not only for the integer spin case, but also for spins 1/2 and 3/2, and also to calculate masses for exotics. in order to do this we considered anomalous dimensions for operators that create hadrons, and the dilaton that was used has a form suggested by einstein s equations, corresponding to the ads metric. as a result  , the model can describe hadronic masses in a unified phenomenological model.
the large scale geometry of metric spaces is well known, and the action of mappings or transformations on metric spaces using convergent sequences at infinity is well studied.   the central aim of this paper is to develop a theory for understanding the large scale geometries of metric space and the actions of mappers or transformations with reference to the theory of gromov hyperbolic spaces. in this paper  , we will focus on mappings between metric spaces which send sequences keeping the condition of the convergence at infinity. such mappings are called asymptotically conservative with the gromogramov product ( or asymptic_conservative ). here   we will show that the concept of asymptonic conservative mappings is not only applicable to the problem of teichmller space, but also to other metric spaces. by taking into account the fact that the tautomeric aspect at infinity of a metric space is always less than a negative constant, it is possible to obtain an equivalence relation on the set of convergent sequence at infinity in a given metric space where the topological aspect is always more than a positive constant. from these results, we propose a new theory for studying the
the pattern of temperature anisotropies in the cosmic microwave background ( cmb ) has been observed by the wilkinson microwave anisotropy probe ( wmap ) over a wide range of angular scales and is consistent with the standard flat @xmath5-dominated cosmological model of the universe.   the wmap data, however, have also revealed unexpected anomalies that have sparked considerable attention. these include a dip in the first doppler peak around the north ecliptic pole and a lack of large - angle correlations in the low-@xmath10 multipole alignment at the center of the power spectrum. here   we estimate the primordial power spectrum using data from different regions of the sky according to the two weighting schemes that have been used to extract the best fit power spectrum : the noise weighting scheme for the first year wmap release and the newly adopted noise weights for the second and third year releases. while the first peak shows a substantial suppression of power in both schemes, the magnitude of the suppression depends on the binning used to present the data and the analysis strategy used by wmap in their first year release.
the recent observation of apparent tidal tails around the giant galactic globular cluster @xmath3 centauri ( ngc 5139 ) by leon, meylan & combes ( 2000, hereafter lmc00 ) has led to the suggestion that this cluster may be the nucleus of a disrupting dwarf star population ( dsph ).   we re - evaluate the possible impact of differential reddening on the morphology of the observed tidal tails and metallicity distributions of the three other potential multi - modal globular clusters proposed to be m54 analogues, ngc 6388 and ngc6441, since both have observed characteristics suggesting multiple metallicities within the cluster. in each case study, we show that differential redening can create false signatures of both tidal tails at the core of the cluster and of multiple metallicity within it, which could be mistaken for, or overemphasize, density enhancements from tidal tails. because these effects are non - negligible, we propose that the presence of multiple populations of stars in the cluster is not due to differential extinction, but to dust - shaping of the morphological features of the tidal tails as well as to the formation of new metallicities inside the cluster itself.
we propose a new method to measure the mass of an isolated rapidly rotating non - axisymmetric neutron star ( ns ) that emits gravitational wave ( gw ).   the method is based on the fact that the coulomb type gravitational field of the star itself modulates the phase shift of the gw waveform, which is well - known in quantum mechanics and partly incorporated in the gravitational wave waveform from a compact binary coalescence ( cbc ) event. by using this new method, we can estimate masses of isolated nss by detection of those sources with one of proposed third - generation telescopes, namely, einstein telescope ( et ) @xcite.
bar bars are the most frequent non - axisymmetries developped in galaxy disks.   they form easily in numerical simulations, even when the effective kinematic viscosity is of the same order as the star - formation time - scale, i.e. the viscous time - scales of the first systems to form are disks. from the near - infrared image, representing the old stellar component,   it is possible to deduce the gravitational potential of the galaxy. from these calculations, it is then possible to compute the average torque exerted on the gas at each radius, assuming a stationary state at least for one rotation. here  , we show that the magnitude of the torques depends on the bar strength, and on the phase shift between the gas response and the stellar potential. using this information, we derive a model of the evolution of the bar, which assumes that the disk evolves through its gravitational instability, producing non -axisymmetric features or waves, that will transfer angular momentum : the bar is a wave with negative momentum, with most the orbits sustaining the bar with high eccentricity. by taking into account the fact that the bar can be destroyed by the mass of the
in a recent paper @xcite, liddle and urea - lopez studied the conditions under which we can have a unified description of inflation, dark energy and dark matter.   the key ingredient required is to have a reheating process where not all the inflaton energy density decays into radiation. in this work   i revisited this issue by studying the preheating scenario of reheating, where it is known that the scalar field decay can be incomplete. using the standard reheating mecanism, we can obtain a partially decaying inflaton field, but this observation does not help to build the model by itself, because for a large initial amplitude of the infloton field, which is @xmath0 at the end offlation, we cannot neglect the parametric resonance effects on the evolution of the field. here   I discuss the observational constraint and the solution to the problem.
the conservation laws are the most important object in the classical mechanics as well as in the field theory.   the most popular method of the constructions of these laws is the so called recursion operator or lax operator formalism. in this paper   we would like to show that it is possible to construct new extra series of conserved densities for the polytropic gas model and nonlinear elasticity equation avoiding using recursion operators or lax formalism.we generate many nonequivalent hamiltonians of the given dimensions, using symmetry operator. our hamiltonian expressions are non polynomial expressions which contains logarithmic functions. on the other hand  , it appeared that for the nonlinear schroedinger equation it was possible to find one series of homogeneous solutions expressed in terms of the elementary functions only. however for the shallow water equation, which is the dispersionless limit of the non linear schroedsinger equation, there is additional series of Conserved Hamiltonians which is impossible to obtain by recurrence operator ( see for example @xcite ).
low surface brightness ( lsb ) galaxies have been receiving increasing attention since their discovery, in part because their properties substantially increase the range in galaxy properties over which theories of galaxy structure, formation and evolution can be tested.   in particular, the rotation curves of these galaxies provide important clues to the distribution of dark matter. here   we review the new h@xmath0 rotation curves for five lsb galaxies, and discuss the implications of these curves for the mass models of lsb universe.
class i sources in the taurus - auriga cloud have blackbody - like spectral energy distributions that peak at wavelengths of 30100  and bolometric luminosities, @xmath1 0.1100 .   we use optical spectra of t tauri stars to calibrate the spectral types of class i sources and then construct a complete rate - limiting evolutionary diagram for the Taurus - Auriga cloud using new evolutionary tracks for protostars accreting from discs and two spectral types derived from near - ir spectra. these data, coupled with new observations of the photospheric absorption features of the central stars of classi sources, show that they mingle with t tauris and lie below the birthline in the hr diagram. forbidden emission from  is much more common among class i Sources than older, optically brighter stars having the same bolometric luminescence. also, the fluxes of forbidden emission lines seem stronger among class I sources than other pre  main - sequence stars in the cloud. despite many detailed studies of their circumstellar environments, understanding the stellar physics of these objects   has proved elusive.
we investigate the nature of non - gaussian groups of galaxy systems.   we use a subset of the 2pigg catalog, corresponding to groups located in areas of at least 80% redshift coverage in 2df data out to 10 times the radius of the systems, roughly estimated from the projected harmonic mean. using the anderson - darling test, we have classified the groups after applying the ad test to their galaxy velocity distributions. for different distances,   the groups are divided into two subsamples : a gaussian ( g ) and a non -gaussian ( ng ) subgroup. with the kolmogorov - smirnov ( ks ) and cramer - von mises ( cvm ) tests, we find that the mass distributions of the g and ng groups are not significantly different. by combining the ks and cvm tests with the virial analysis, we show that there is a significant segregation effect on the mass distribution of the non - Gaussian groups, which is explained by the effect of secondary infall onto the g groups. when we extend the analysis to regions where galaxy groups might not be in dynamical equilibrium, we found that the separation effects are more pronounced for the ng groups
the origin and formation process of the mid - infrared mgi  emission features in procyon, an f5iv - v star, at 811.578 @xmath3  ( 12.3217  ) and 818.058  @x Math3.   ( *????* hereafter crs ) was first explained by ( *???'?,we have analyzed the procyan mgi lines as crs successfully did for the solar mgiemission using non local thermodynamic equilibrium ( nlte ) analysis of magnesium in the solar photosphere. from these calculations, we show that the observed emission is due to the formation of a rydberg state of mgi in the photosphere, which refills the high - excitation levels and subsequently photoionizes the lower lying levels, leading to the emission.    the upper levels are overpopulated and photoionized by rydberge states of mgii , which then refill the low - excite the lower - excited levels, resulting in the line emission. because zeeman splitting depends on the square of the wavelength while doppler broadening goes as the first power, mid -
active galactic nuclei ( agns ) are known to be powered by a supermassive black hole with an accretion disk.   the spectra of agns are characterized by a nonthermal featureless continuum with prominent emission lines exhibiting a large range of ionization and excitation. in the presence of an optically thick component, it is expected that far uv radiation can be inelastically scattered by neutral hydrogen, which may result in scattered radiation in the visible and ir regions. here   we use spectropolarimetry to find polarized residual fluxes in the broad absorption troughs in the spectrum of o  vi@xmath111032 and 1038, a type 2 seyfert galaxy that exhibits broad absorption lines in the blue part of permitted broad emission lines. using the reverberation mapping method, we show that the broad emission line region is located within @xmath8 from the central engine, whereas the narrow emission lines do not exhibit flux variations correlated with the neighboring continuum. this observation is consistent with the unification model of agn unification, which proposes that an Optically and geometrically thick components resides between the broad emissions region and the narrow emissions region, hindering the
pulsating subdwarf b ( sdb ) stars can be resolved from single - site data.   we report the results of our follow - up observations on the sdbv stars pg  0154 + 182 ( hereafter pg  0054 ), hs  1824 + 5745 ( hereafter hs < 1824 ), and hs > 2151 + 0857 ( hereafter Hs < 2151 )..we resolve the pulsation spectrum of these stars using high - speed readout at 2.4  m and 1.3  m telescopes combined with higher signal - to - noise ( s / n ) observations on a 2.5  m telescope.  in addition, we detect low amplitude pulsations that were below the detection limit of the discovery data. for all three stars,   the observed pulsations are unresolved and appear to be single with @xmath10 and @x Math10=15.6 and @ xmath11=16.5, respectively. by resolving the pulsations, we can obtain estimates of total mass, luminosity, shell mass, radiative levitation, gravitational diffusion, and helium fusion cross sections.
the transversal polarization of a quark scattered from a transversally polarized target in deep - inelastic polarized lepton  polarized nucleon scattering experiments @xcite has been measured experimentally for the first time.   the measurement of the transverse quark polarization is interesting in many aspects, and one of the most important of them is quarks transversity distribution in proton @xmath5 measurement. to do this, one needs to know the transversum of a non - polarized or a zero spin hadron with respect to a transversely polarized quark. here   i briefly review the results of t - odd parton fragmentation functions ( pffs ) measurements and discuss the application of this method for estimation of the proton transversality distribution.
solar dynamics usually affects the emergent spectral line polarization in a complex way that can not be explained as a mere doppler effect.   the present work connects for the first time observations with magnetic field theory ( mhd ) models through the synthesis of hanle and zeeman polarization in time, space, and wavelength using time - dependent 3d r - mhd models of the solar chromosphere including non - equilibrium hydrogen ionization @xcite to solve the nlte problem of the second kind for the cai @xmath0  line at the disk center. by studying the spatial dimension of the model, we show that the observed polarization is a direct spatial fingerprint of the chromospheric magnetic field that is highlighted in presence of motions.
we study the fragmentation of a filamentary isothermal cloud @xcite in three - dimensional magnetohydrodynamical simulations using the nested grid method.   we use the barotropic equation of state to calculate the non - axisymmetric dynamical contraction of the cloud from @xmath5 to @x Math4 in number density, and we investigate how fragmentation proceeds and outflow occurs in the course of binary star formation. for the first time, we consider a cylindrical isothermal gas cloud in hydrostatic balance as the initial condition and we find that the density, azimuthal velocity, and magnetic flux density distributions in the radial direction are taken to be as follows@xcite : ^{-1/2 },     \end{aligned}\ ] where @xMath9, @x math10, and @x maths11 represent the densities, angular rotation speed, andmagnetic flux density at the center of the cylinder cloud, respectively. when the density of
the holographic principle was put forward in 1993 by @xcite and asserts that all of the information contained in some region of space can be represented as a hologram, a theory located on the boundary of that region.   this theory should contain at most one degree of freedom per planck area. in this paper   we study how the holographic concept applies to an accelerating universe filled with a tachyon scalar field with a constant equation of state ( eos ) for both the spacetimes of the region @xmath3 and the phantom domain @x Math2. in order to do so  , we shall make use of a covariant procedure @xaite and the results will be confronted with those given by the holog graphic dark energy model with the future event horizon as the infrared cutoff @xcitesite.
the fractional quantum hall effect results from the formation of a strongly correlated spin polarized electron liquid in the lowest landau level, that crystallizes below filling 1/7 @xcite.   it is intriguing, however, that a mean field charge density wave solution exists at all fillings, called a hall crystal ( hc ), which yields in a natural way the odd - denominator rule that characterizes the effect. in this work   we report results for the correlation energy of the hc at @xmath1 filling. using symmetry considerations, we show that the electron - electron interaction breaks the single particle degeneracy of the lowestlandau level by splitting it into three remarkably flat bands.    all bands contain the same number of states so that only one is filled while the other two are empty, separated by a large gap.. the narrowness of the occupied band and this latter fact suggest that the magnetic wannier states are approximate solutions of the problem and behave as nearly free quasiparticles filling the lll of the effective field@xmath5 much as the composite fermion model predicts.
coronal mass ejections ( cmes ) are among the most powerful solar energetic particle events in recent history.   they can occur with or without a powerful flare and withor without a prominence eruption, but the fastest, most powerful cmes seem to be associated with flares. here   we present ultraviolet ( uv ) observations of 3 very fast cmes associated with x - class flares on 21 april, 23 july and 24 august 2002. all three events show transient brightenings in the  line and little or none of the cool gas that usually dominates uvcs spectra of cmes. in all three cases the pre - cme streamer is violently disrupted, and the o vi line profiles split into strongly red- and blue - shifted components, and this is accompanied by a region of split profiles along the spectrograph slit that grows rapidly as the doppler velocity increases from ~100 to ~2,000 @xmath0 k. the components of the split profiles are relatively narrow, indicating a lack of strong shock heating. these observations are consistent with the hypothesis that the most energetic cmes arise from active regions where a great deal of energy is stored
the three most relevant detection schemes in quantum optics involve different ways of coupling signal to probe modes.   they are the heterodyne @xcite, the eight - port homodyne@xcite and the recently introduced six - porthomodyne detectors ( tri ).. it is a purpose of this paper to show that all of them jointly measure the real and the imaginary part of the complex photocurrent, which is the real component of the signal mode and the probe mode, and that their output photocurrents have the same operatorial form. even when taking into account the inefficiency of photodetection, which occurs at very different stages in the three detection schemes, these two - photocurrent devices provide the same information on the signal under examination.
the relativistic high - order harmonic generation ( hhg ) by hydrogenlike ions in the uniform periodic electric field, formed by the two linearly polarized counterpropagating laser beams of relativistically intensities, at the distances much less than a laser wavelength, is studied.   the effect of the magnetic field of a strong laser pulse on the hh g in the relativists regime caused by the magnetic drift of a photoelectron due to the electromagnetic field of the strong electromagnetic wave is considered.. the effective hhG in the field of an ultraintense laser pulse in the own frame of reference is obtained by transforming the traveling laser pulse with the pulse group velocity in plasma into the uniform periodical electric field and the wave magnetic field in this case vanishes completely, in contrast to a standing wave configuration formed by counterspray laser pulses of different intensities.
soft glassy systems are non - ergodic systems that exhibit slow relaxations strongly reminiscent of the glassy dynamics observed in hard condensed matter.   they include concentrated or strongly interacting colloidal suspensions, emulsions, surfactant systems, polymeric or colloidal gels, and foams. until very recently, the experimental characterization of the dynamics was limited to relatively short time scales ( e.g. up to a few hundred seconds in light scattering experiments ) and only the average dynamics were accessible. theoretically, very few quantitative models were available, and their applicability was restricted to a small number of model systems. on the experimental side,   recent advances include both the design of new systems with interactions that can be fine - tuned and the development of new methods and techniques to measure very slow and heterogeneous relaxations in out - of - equilibrium systems. here  , we review the most popular techniques for probing the dynamics of soft systems, including optical microscopy and dynamic light scattering.
time delays are present in many different physical or biological systems, and are particularly able to account for many features of ecological phenomena, although they have not been studied extensively. in this paper   we introduce a new model of the predator - prey problem with history - dependent dynamics.   the predators stray randomly in a plant - full environment, eating them when they find any, but the eaten plant will regrow after a definite elapsed time. as a result, the predators reproduce with a constant rate and die, if they haven’t eaten anything in a specified length of time.the time evolution of the mean spatial densities of predators and plants is studied by discrete - time, lattice - based computer simulations, as well as by a mean - field approximation solution on a square lattice with periodic boundary conditions. from the results obtained from simulating the model,   it is shown that the space correlation of the densities can eliminate the chaotic behavior of the model.
the number of known binaries of g - type stars is about three times larger than reported by dm1991.   this increase is due to the availability of new sources of binarity and multiplicity data, including the hipparcos catalogs. in this paper,   i present evidence that the apparent binary frequency ( @xmath1 ) of a g - star sample is substantially larger than previously determined, and that the steep drop - offs towards larger distances and fainter magnitudes are unphysical and in fact the result of selection effects. given that the sample most favorable for the detection of companions has a multiplicity fraction of 95%, i suggest that in fact _ all _ stars are part of a multiple system.
we report on the preparations and results of two experiments to search for hidden - sector photons ( hp cdm ) in the ev mass range using a novel method with a spherical mirror and a photodetector.   we used a parabolic mirror as a ` dish'to use hpcdm near the surface of a reflector to induce emission of photons in the direction perpendicular to the surface, which are detected by a photomultiplier tube ( pmt ) at the point of convergence of the emitted photons and at the position displaced by 25 mm from the center of the mirror sphere. both experiments were carried out in the @xmath5 band using optical equipments and the other in the@xmath6 band using rf instruments. during the first experiment, we found no excess in count rate measured at position s compared to at position b. this non - detection result was translated to the upper limit for the kinetic mixing parameter @x Math2  @xcite. for the second experiment, our results show that the same set - up is feasible for the search for hp cdms in the ~11 frequency region.
the nuclear partition function at high temperatures is essential in understanding the nuclear equation of state used in the core collapse phase of massive stars.   recently, new sets of partition functions have been published along with astrophysical reaction rates for nuclides from proton dripline to neutron Dripline and charge number @xmath5 @xcite. here  , the extension of these partition functions to temperatures of @x Math7 is presented. due to the temperature dependence of the integrand,   its peak contribution is shifted to higher energies for higher temperatures @xMath18, thus also requiring a larger cut - off @x math15.. the corrections are treated by closely following @xcites.
the self - scattering cross - section of dark matter in the central regions of galaxy clusters has been estimated as @xmath6 ( c.f.   @xcite ), which is the most stringent upper limit on the cross - sections per unit mass, based on the assumption that the measured ellipticity comes solely from the core of the cluster, instead of projection of mass from outside the core, and that there has been no recent merger activity in the cluster. here   we present a new method to estimate the separation between the stellar and dark matter components of a galaxy, using a combination of cosmological parameters and density of darkmatter. for each galaxy,   the separation is calculated as a function of the dark matter space density and the force of gravity between the core and the two components of the galaxy, and the distance between the stars and dark Matter.    the method is validated by comparing the results with those obtained from the bullet cluster@xcite, a plane of the sky collision between two galaxy clusters.
the theory of the spiral of silence ( tss ) is formulated by means of a new computational model.   the key issue is how the effect starts and develops. in the literature,   it has been formulated in terms of a weighted social network of interacting agents ; yet the model became so complex that it does not contain any calculations. here   we propose a new formulation of the problem by using a set of nonlinear difference equations on the population dynamics. to keep our considerations within reasonable frames  , we concentrate on tss, where - up to our knowledge - the effect has not been discussed yet.we find that the variation of the group content plays a major role in the development of the effect.    the results show that the term spiral is justified in our model.
soft x - ray transients ( sxts ) are close binary systems which undergo large amplitude outbursts with a recurrence time of about @xmath1 years.   most of the outburst energy in an sxt is emitted in rather soft ( 1 to few kev ) x - rays, and it has been claimed that the spectra of black  hole sxtes ( bsxts)are characterised in outburst by an ` ultra  soft'component, namely nova muscae 1991 which had an e@x math2@xmath3 annihilation line.    in this paper we analyse how various versions of the disk instabilty model could be applied to outburts of bsxf transients. as in the case of their close cousins, the dwarf novae, which have central white dwarfs instead of neutron stars or black holes,   two kinds of models have been proposed to explain the outburbs of these transients : the dim disk instability model ( dim ) and the mixed model ( mdd ). while the dim model is able to produce the observed short timescales, the mdd model is not able to reproduce the observed long timesc
abstractthe wfc3 infrared spectroscopic parallels ( wisp ) survey has obtained slitless spectra over @xmath7@xmath8 m for more than 700  kpc of sky using the two infrared grisms installed on the ir channel of wide field camera 3 ( wFC3 ).   these spectra were systematically scanned by at least two observers to search for three cold brown dwarfs of type t and now y, which were identified by comparing them to 69 t dwarf spectra from the spex prism spectral libraries @xcite and two additional y dwarf spectras from @xcites.  in addition, we have also identified a methane dwarf of type g1229b, a methane - rich t2-type brown dwarf of ~1.5  km in diameter, and a gas - rich y dwarf of about 1.6  km with a temperature of ~0.9  k. these discoveries illustrate that wfc4/wfc3 grism spectroscopy can be used to probe the galactic spatial distribution of the ultracool dwarf population and search for substellar members of the halo population.
tidal theories have gained great attention in the last decade due to the large number of discovered close - in planets which orbit their parent stars with periods of a few days.   the long - term tidal evolution of these planets results in orbital decay and circularization, on time - scales which depend on the physical properties of the interacting systems. for non - circular orbits,   synchronous rotation only occurs if an additional torque acts to counteract the tidal torque. here  , we study the equilibrium rotation of mercury, a rocky planet with a rotation state currently evolving in the 3/2 spin - orbit resonance, under the assumption of a tidal evolution driven by tidal torques. using a dynamical model of the evolution of the planet s rotation, we find that the equilibrium value of the rotation period of gj 581 * d * is probably about two times larger than the observed value for the same planet in the same orbit.. the resonant state of mercury is likely to be a result of the combined effects of the tidal and asymmetric torques generated by the gravitational interaction of the star with an asymmetric planet, which drive the planet rotation into different regimes of motion, including oscillations around exact spin -
gravitational waves are the propagation of a wave of space - time curvature, and are generated by perturbations in massive systems.   gravitational waves are thought to exist over a broad range of frequencies up to @xmath9  hz, but at a reduced amplitude compared to low frequency sources sensitive to laser interferometer ( ligo ) detection. in this work   we aim to revive the resonant - mass detector for the first cosmic search of high frequency gravitational wave radiation based on piezoelectric quartz bulk acoustic wave ( baw ) resonators. despite dominance of the low frequency gw detection,   this technology opens the way to test for known and unknown high frequency sources.the proposed detector will be able to detect gravitational waves at very low temperatures ( below 20 mk ) using quartz bulkoustic wave resonators which are naturally sensitive to gravitational waves with strain sensitivities of order@xmath6.    the detector will also be able not only to detect millisecond bursts, but also to detect large - scale events such as supernovas and binary black holes.
ultraluminous x - ray sources ( ulxs ) are non - nuclear x - rays sources in external galaxies with apparent luminosities above the eddington limit for a @xmath7 black hole, the maximum mass of any dynamically - measured black hole mass in the galaxy @xcite.   the ulx in the dwarf irregular galaxy ngc 5408 ( ngc5408 x-1 ) is variable and is one of the few ulxs with a known radio counterpart @xcites. to better understand the nature of the radio emission from this source, we obtained new joint observations in the radio using the very large array ( vla ) of the national radio astronomy observatory ( nrao ) and in the x -ray using the _ chandra X - ray observatory_. in addition, we present new and archival radio observations from the australia telescope compact array ( atca ). finally, we also reanalyzed archival optical observations made using the hubble space telescope ( hst ).
the british scientist isaac newton ( 16421727 ) was a controversial figure in the history of science.   his reputation has long been secure, but the details of his personal and intellectual development have undergone much posthumous scrutiny and second - guessing, from which no clear portrait has emerged. this article reviews the conflicting accounts of those who knew him and from his multifarious personal papers that have been published in the last two decades. while many of the accounts of newton s life and work have been written about in the past, little is known about his personal life and his scientific achievements. to be sure, newton was high - strung, wary and secretive in his dealings with others, and intolerant of criticism, but there are few instances in which he can be convicted of bad faith. during the last thirty years of his life he served as chief officer of the royal mint, earning nearly unanimous praise for his diligence and honesty. according to mint official and historian sir john craig,newton was not only personally conscientious but also "a good judge and handler of men" endowed with " magnetism which in many engendered an extraordinary regard and respect''. according by the estimation of
we investigate the modification in the total detected number of events ( @xmath0 ) by the introduction of the lorentz invariance violation ( liv ) parameter in neutrino oscillations for a neutrinos factory with @x Math3 muon decays per year localized at a distance of 7500  km from the detector.   the experiment is based on a model based on the standard - model extension ( sme ) which is an extension of the standard model with Lorentz violating terms in the lagrangian. to determine the liv, we measure the time of flight of the neutrines and their energy - momentum relation in the hamiltonian using the minos experiment  . we find that the detection times of the near and far detectors of 3  gev neutrini beams are significantly different when the liv parameter is introduced into the model. according to our calculations, this difference is due to the existence of a very small effect of the cosmotic decay of the muons in the factory on the total number of observed events.
the production and decay of the neutral top - pion @xmath27 at high energy@xmath6 colliders(lc ) have been studied using topcolor assisted technicolor ( tc2 ) theory.   the results indicate that the main contributions to the production cross section of the Neutral Top - Pion are expected to come from the @x Math7 channel at the lc experiments. in this channel, we find that several hundred events of @x math0 can be produced per year by assuming an intergrated luminosity @x maths29.. possibly, a smaller @xMath0 production may also be observed in the @Xmath30 channel.    the signatures and observability of these new particles are discussed.
we study the behavior of the @xmath1 kink under perturbations.   we know that it is stable, but we want to know how extra energy of a perturbation is dissipated. in this way  , we use a finite difference scheme to solve the differential equation of the model with a gaussian profile. when the amplitude is small enough, the extra energy is dissipate through radiation. beyond the threshold of four times the energy of the kink, it can appear a kink - anti kink pair and if the energy is high enough an oscillon.
one of the important properties of diamond - like tetrahedral amorphous carbon ( ta - c ) is its possession of high average compressive stress.   the origin of this stress and its relationship to the formation of sp@xmath1 sites is still a matter of debate @xcite. in this paper, we take into account the surface environment and examine how global this relationship is. by analyzing consistently the variations of stresses and the distributions of atoms as functions of depth, we unambigiously show the validity of the local stress - bonding hybridization relationship in ta-c.
planetary systems are thought to form out of circumstellar disks that are the remnants of star formation.   it has been suggested that these disks evolve from optically thick to optically thin structures in about 10 myr, and that this transition may mark the assembly of grains into planetesimals, or clearing of the disk by planets. since age estimates for early - type isolated main sequence stars are highly uncertain, however, the timescale for disk evolution and planet formation is poorly constrained, and may depend critically on the presence or absence of a close binary companion. here   we show that many of the stars in the tw hydrae association ( twa ) have little or no disk emission at 10 @xmath3 m. we imaged a spatially - resolved dust disk around the young a star hr 4796a using the oscir instrument on the keck ii and ctio 4-meter telescopes and found that the surface brightness distribution of the disc is consistent with the presence of an inner disk hole of@xmath450 au radius, as first suggested by jura et al. over the past three years  , we have obtained mid - infrared observations of tw hya stars with excesses at
type iib supernovae ( sne ) are a rare type of supernova that are thought to be the result of core - collapse of a type ib progenitor.   we report on imaging observations of sn  2008ax ( p08 ) with the _ swift _ @xcite ultra - violet / optical telescope ( uvot ; *???   * ), the x - ray telescope ( xrt ; *????'?,the sn was discovered on 2008 - 03 - 3.45 ( ut ) in ngc 4490 at@xmath15, @xmath16 and @x Math16 by pastorello et  al. since the time of the shock breakout was approximately six hours earlier than the detection time in p08, we used this time to set the time for the uv observing of the sn from 2008 - 04 - 04 to 2008 - 06 - 26.    the uVot observed the sn using three optical and three uv filters with a cadence varying between @x math20 using three different sources. during the observation,   the sn exhibited a peak magnitude of ~2.5  kcal / mol in the blue band and a
the solar wind ( sw ), predicted by vsechsvyatsky, ponomarev, parker, and van der waals, is a regular component of the solar wind.   the slow and fast components are regular : the slow one exists always, and the fast one is observed periodically. according to the observations of radio scintillations on inhomogeneities of the interplanetary medium, the mechanism accelerating sw particles is either completely different or has essentially different parameters for different components. in this paper, we analyse the microwave emission of coronal holes ( ch ) in the solar atmosphere obtained from the nobeyama radioheliograph ( norh, 17  ghz ) and the siberian solar radio telescope ( ssrt, 5.7  Ghz ), carried out at the same frequency range as the solar limb, using the uv spectrograph sumer on board the spacecraft soho @xcite. with the use of the sumer data, we show that the maximum of the high - speed sw characteristic is reached at ch levels in the lower solar atmosphere with temperatures of about @xmath7 k ( in the transition region ).  also, the
the properties of bose - einstein condensates ( becs ) in lower - dimensional geometries have attracted much attention because of specific coherence properties of degenerate bose gases in lower dimensions and possible experimental realization of quantum gases beyond mean field approach.   the aim of this article is to give analytic treatment of the lower dimensional expansion of bec under conditions that the three - dimensional gross - pitaevskii ( gp ) equation can be reduced to its lower dimensional counterparts by means of hydrodynamic approximations with initial conditions corresponding to the equilibrium states of a confined in the parabolic trap bec with positive scattering length. if the conditions of lower dimensional reductions of gp equation are not fulfilled, then effects of 3d hydrodynamical flow can be estimated with the use of variational approach what is done in @xcite case without discussion of free expansion dynamics.
the formation of molecules from cold atoms in optical lattices has been demonstrated experimentally by several groups.   we consider a gas of two - component fermionic atoms coupled to bosonic molecules via photoassociation in an optical lattice, and examine the crossover of the dynamics from an independent single - site regime to a cooperative regime. as the ratio of repulsive molecule - molecule interaction strength to molecular tunneling is varied, the dissociation dynamics of the molecules becomes more cooperative, and the self - trapping transitions between the coherent and incoherent regimes become more prominent. using a spin - boson lattice hamiltonian  , we show that the coherence of the atom - molecule oscillations can be described by a pseudo - spin formalism, and give a formulation of mean field approximation based on a generalized gutzwiller ( gw ) ansatz.
dimerization of low - dimensional antiferromagnetic spin chains leads to the appearance of a free spinon at the edge of the chain end.   this spinon is not localized at just one site, i.e. it is able to move some distance away from the defect. in a critical, gapless system, however, it will be delocalized. here   we show that this delocalization disappears as soon as the couplings are modulated by coupling to the lattice degrees of freedom. for a chain end with a weak dimerization,   the confinement depends on the degree of frustration and it is sublinear in the region of low frustration. in the case of a chain with a strong bond defect, the confinement is more complex and sublinear when the frustration is small but not large.
we show that classical collisional transport across the magnetic field is included in drift - fluid models of edge and scrape - off layer turbulence in magnetically confined fusion plasmas based on the braginskii fluid closure@xcite.   we show how this is consistent with the results of mean field transport models and turbulence models and that it is also important for the interplay between collisions and turbulence because of its diffusive nature, which inevitably determines the smallest possible scale length of the turbulence below which the turbulent energy is dissipated. compared with neoclassical transport,   classical perpendicular collisional transportation is small in most regions of a magnetically trapped fusion plasma but is important in turbulence dominated systems such as drift wave turbulence. here  , we present a step towards more detailed edge and scraping - off layers turbulence models by showing how classical collisionals are included in drifting- and vortex - free models of ion temperature dynamics and turbulence.
the theory of stochastic evolution provides a beautiful connection between dynamics and statistical physics.   it is well known that, due to the gaussian white - noise distribution, the continuum limit of the discretized time evolution of multiplicative processes is not unique. in this work  , we would like to present a study of equilibrium properties of markovian multiplicative black - noise processes, which can be represented by the langevin equation. as a prototype of these processes,   we consider the case of a diffusion of a brownian particle near a wall with a viscous force and a non - homogeneous contribution of fluctuations. for each of the diffusion parameters, the time reversal transformation of the process is considered and the equilibrium property of the system is studied.. the results show that the model is able to reach equilibrium at the end of the forward trajectory of the multiplicative process if the diffusion parameter @xmath1 is defined in such a way that each value of the parameter corresponds to a different discretization rule of the stochastically differential equation.    the equilibrium properties are discussed in detail in the more general prescription called generalized stratonovich convention   ( also called " @x
the deng - fan diatomic potential model also known as the generalized morse potential which was proposed some decades ago by deng and fan @xcite is used to obtain the bound state solution of the schrdinger equation.   the energy levels of all the bound states are easily calculated from this quantization rule. in the present work,   a new exact ( improved ) quantitative rule is proposed for the calculation of the boundState solutions of the deng-fan molecular potential model. using this rule, the obtained bound state solutions of these potentials are compared with the results obtained by using the same rule for the deformed harmonic oscillator in one dimension, the kratzer potential and the pseudoharmonic oscillators in three dimensions.
galaxy clusters are cosmographic buoys that signal locations of peaks in the large - scale matter density.   the population is shallow and finite, and surveys in the coming decades will definitively map our universe s terrain as defined by the highest @xmath0 peaks. a key aspect of their multi - component nature is the fact that clusters offer multiple, observable signals across the electromagnetic spectrum ( e.g. *????)cluster cosmology is a challenge to cluster cosmology because of the need for accurate statistical models that address survey observables explicitly while incorporating intrinsic property covariance. here   we review the current state of knowledge about the properties of galaxy clusters and discuss how they can be used to test theoretical models of cluster evolution.
we investigate the formation and evolution of galaxy clusters in early universe using cosmological simulation.   we perform a cosmologic n - body simulation with particle - particle - particles - mesh ( @xmath18 ) algorithm and compare our results with those of observations by @xcite and@xcite, which have shown that number density of ly@xmath8 emitters ( laes ) in a region around a radio galaxy at @x Math17 is much higher than the mean of the universe suggested by @xaicite at @Xmas. in this region,   there is a circular region of high surface density of laes with 12 mpc radius, which may be a progenitor of a galaxy cluster. to better understand the properties of simulated proto - clusters, we use the hierarchical friends - of - friends ( hfof ) method for the selected dense particles and find that the maximum linking length of the region is ~2.5 mpc ( physical ) and the mean inter - particle distance for all ( not only dense ) particles is ~1.4 mpc. on the other hand, the mean density of total matter is ~0.6 mpc in the region where the
we present a new model of cold dark matter ( cdm ) dominated cosmogonies that is consistent with most recent observations.   the model is based on a low - density open model with a constant or time - variable cosmological  constant " @xmath3 and a flat spatial hypersurface and a nonrelativistic - matter density parameter @x Math13.  in contrast to the open model, the flat - constant-@x math3 model has either a non - zero or a constant/time - variable Cosmological constant @x maths3 which are consistent with current observations but not with models - based maximum likelihood analyses of the cosmic microwave background anisotropy data. using a set of constraints derived from a comparison between model predictions and experimental measurements, we find that the latter two models are more consistent with the observed universe than the former. for instance, the rate of gravitational lensing of quasars and radio sources by foreground galaxies requires a large @xMath12 at 2@xmath7 in the single - space model and a small @x mathematics3 at 2 @xometh2 in the double - space case.    this is because the latter is
we report the evolution of the thermal linear - expansion coefficient of a granular column submitted to thermal cycles in a first experimental configuration.   the experiment consists in imposing temperature cycles to agranular column and in measuring the resulting variations of the column height. here  , we focus on two physical properties of the granular pile, namely @xmath0, its thermal linear-expansion coefficient, and @x Math1, its thermally conductivity, which both evolve in time because of temperature varations. by means of a time - resolved study of the dynamics associated with the compaction of a 3d granular heap submitted to temperature cycles, we demonstrate that temperature variations, even of a few degrees in amplitude, also induce ageing in a granule pile exactly as moisture, constant applied - stress and chemical reactions between grains do.
we describe a general approach to compare the relative figure of merit of two observational techniques, the optical long baseline interferometer ( olbi ) and the classical single telescope spectroscopy, both used to find the parameters of the gaseous envelope around the p cyg star.   the approach is based on the comparison of the corresponding errors in the model parameters determination of the two techniques, and is applied to the optimization of complex observations, thus contributing in maximizing their scientific output. for this first trial application  , we use simulated data, obtained by solving the radiative transfer problem for grids of physical models of the envelope and then adding the photon noise, to show that the olbi technique is superior to the spectroscopic technique in terms of its ability to determine the spectral profiles and visibilities of the h@xmath1 line of the p  cyg envelope.
the influence of short - range correlations on the presence of high - momentum components in the ground state of @xmath7@xcite has been calculated from a realistic interaction without recourse to some form of local density approximation.   the spectroscopic factors for the removal of proton and proton with valence hole quantum numbers from the single - particle ( sp ) strength are calculated for the quasihole states of @Xmath4, @x Math5, and @x math6.    the results show that only about 70% of the expected protons in the nuclear ground state can be detected in the energy and momentum domain at small missing energy. with increasing missing energy  , however, one recovers the high - Momentum components which have been admixed into their ground state.. the contributions of short- and long - range effects are discussed.
we show that the existence of two phases of full counting statistics ( fcs ) is a very general feature of fcs : phase transitions between them occur both in classical stochastic models and in quantum systems.   we illustrate our discussion with several examples : the classical weather model and quantum systems of noninteracting fermions. for quantum examples, we use the results of our recent work@xcite to show the stability of the analytic phase for a wide class of non - interacting fermionic systems, even at finite temperature. finally, we discuss a possible identification of the two phases in terms of cumulants and conjecture the general form of the asymptotic long - time behavior of the fcs in the nonanalytic phase.
we propose a method to classify highly nonlinear profiles from corrosion tests using multi-@xmath0 statistics.   the method is based on the concept of entropy, which represents how close a given probability distribution is to the uniform distribution of the system's microstates. in the present work,   48 polarization curves produced from two stainless steel classes, with different resistance against localized corrosion, in aqueous chloride medium, are classified by means of a multi- @x math0 approach. for each class, we find that the polarization of both materials is very similar, especially in the cathodic region and in the potential immediately past the corrosion potential region, and this similarity produces overlapping curves which require a systematic approach to classify, an analysis that has not been routinely carried out in this field. as expected, for any set of experimental results, dispersion always occurs. however, the level of scattering in polarization curves naturally increases as the localized corrosion takes place, which exhibits random nature. moreover, certain stochastic phenomena such as pitting produce electrochemical current variations that produce overlap in the experimental curves, rendering them almost inseparable. since the kinectic aspects of polarization curves are related to allowed microstates of the
the effects of tidal shocks on the evolution of star clusters in the galaxy are well known.   however, the effect of the adiabatic correction, which is the ratio of the actual energy change to its " impulsive " value, is not well understood. here   we use self - consistent n - body simulations to investigate this problem using a model of the cluster dynamics in which the stars are assumed to move little during the shock and the total energy of the system is conserved. as a function of the star energy and position in the cluster,   the shock - induced energy change is found to be three times larger than the initial kick due to the shock. by taking into account the fact that the cluster is out of equilibrium for several dynamical times after the shock, we find that the magnitude of the perturbing force is much greater than the original formula for the adaption of the shock ( @xmath10 = 0.1 ).    we show that the observed increase in the energy change from the shock to the post - shock period is due to a combination of the gain of energy from the stars and the reduction of the binding energy at the expense of the overall energy change
we report near - infrared and mid - infrared photometry of the @xmath1 velorum cluster using the four channels ( 3.6, 4.5, 5.8 & 8.0 ) of the infrared array camera ( irac ) and the 24 band of the multiband imaging spectrometer for spitzer ( mips ) on board the spitzer space telescope.   these data were collected during 2005 february 23 and april 10 by the irac and mips instrument teams as part of a gto program conducted by the _ spitzer _ science center s irac pipeline. in    we present the observational data used in this contribution, and discuss membership in the  group of young stellar populations. in    we analyze the infrared data and compare with disk frequencies in other young star populations in  , with our main results summarized in -.
the valence band electronic structure of the ( 100 ) surface in the iii  v zinc blende semiconductors gaas, gasb, and insb is studied by angle resolved photoelectron spectroscopy.   the results show that the bulk band structure projected on the surface of the compounds is of two dimensional ( 2d ) character. for the gaas(100 ) surface we find two surface resonances, the first one with anion terminated surface character and the second one with cation terminated surface character. using the tight binding method with the surface green s function matching method ( sgfm )   we have calculated the origin of all those states.
sn 1986e was discovered by g. candeo at m@xmath0 = 14.5 on 1986 april 13 in ngc 4302 ( rosino 1986 ), with a precise optical position of ra(b1950 ) = @xmath1, decl(b 1950 ) = ~2.   recently, interest in the sn has revived with discovery of late time optical emission, a relatively rare phenomenon for supernovae ( sne ), leading to a comparison with other late - time optical emitting sne such as sn 1957d, 1970 g, 1979c, and 1980k. due to these optical similarities and, since all are radio supernova ( rsne ), cappellaro et al.  predicted possible radio emission for sn 1986e with flux densities as high as 0.5 - 5 mjy at 20 cm in 1995, @x Math39 years after optical discovery. this prediction was followed by a search for radio emission in 1995 by eck et al's ( 1996 ), who were unable to detect the sn with very low limits at both 6 cm and 20 cm. here   we reexamine observations taken with the very large array ( vla
we solve gelfand s problem for homotopy classification of elliptic operators on manifolds with corners.   we obtain a simple explicit formula for the classifying group in terms of atiyah s @xmath0-homology functor @xcite, which is derived from the index problem of connes s noncommutative geometry.
the sznajd model of opinion evolution in closed community is one of the important models of some sociological or political events which has been of considerable interest in the statistical physics.   the aim of this study is to introduce a simple sociophysics model to explain the time evaluation of resistance probability of a closed community against occupation by other countries using the ising spin system. for this purpose,   two neighboring parallel spins i.e., two neighboring people sharing the same opinion, convince their neighbors of this opinion and then either they do not influence their neighbors or they bring their neighbors to the opposite position. as a result, the population of a country or a community has been occupied by another country ( or community ) in a military or different way during the history. since human history has been filled with conflicts, invasion or wars among countries or some communities, it is difficult to show that a person or a society has been able to resist the occupation of a neighbouring country or community by other nations in a time- and space - dependent manner.    the present study presents a simple model of the process of consensus finding process based on the sznznajd model where all spins point up or
the chromosphere is in a highly dynamic state, varying on timescales of minutes or less.   much of the dynamics in the magnetized regions associated with the magnetic network and plage are dominated by short - lived, jet - like features that are traditionally called spicules. at the quiet sun limb, they are usually observed in thin, elongated features that develop speeds of 10 - 30 km  s@xmath1  and reach heights of on average 5 - 9 mm during their lifetimes of 3 to 15 minutes. here   we perform a more comprehensive analysis of the properties and motion of these short dynamic fibrils ( dfs ) using the same extremely high spatial and temporal resolution sst dataset of the swedish 1  m solar telescope @xcite as previously reported by @xcitesite. using advanced 2/3d numerical radiative mhd simulations, we show that the motions of dfs are driven by magneto - acoustic shock waves, which are generated by the interaction between the magnetic field and the photospheric p - modes. for most dfs,   the dominant periods of power are between 4 and 6 minutes, but some do show oscillations or rec
we calculate the gamma ray fluxes from the coma and virgo clusters in the assumption of equipartition of the magnetic field with the thermal energy in the cluster, for two different models of the cr injection in the intracluster medium ( icm ), and for different injection spectra and find that in some cases the gamma rays flux is in excess of the egret limit.   moreover, we find that for injection cr spectra flatter than @xmath0 ( for@xmath2 ) some currently operating experiments like stacee, hegra and whipple could detect the gammaray signal from coma or virgo in the tev range, provided the crs are in equipartitions.
the evolution of a parton system from its initial stage toward thermalization is described by two momentum scales, @xmath2 and@xmath3, which are introduced to describe the dynamics of the system from the initial stage all the way to thermalization at 200gev.   the results of this paper can be useful for calculating the yield of direct photons and di - electrons as well as the elliptic flow of Direct photons, in particular, in au+au collisions at @x Math6 collision energy, measured by the phenix experimental collaboration @xcite.
westerlund 2 ( wd2 ) is an unusually rich and compact young cluster located close to the tangent of the carina arm, at @xmath6 degrees.   it contains a remarkable collection of hot and massive stars, including at least dozen o stars and two remarkable wr stars with strong stellar winds. here   we present co(@xmath0 ) observations at a resolution of 1.5 arcmin, taken with the nanten2 4 m sub - mm telescope of nagoya university at atacama ( 4800 m above sea level ) in chile, which reveal that the cluster is associated with a giant molecular cloud ( gmc ) on the far side of the nebula, at a kinematic distance of 6.0 km s@x Math3.    the gmc is composed of a mixture of dense molecular gas and cosmic ray protons accelerated by stellar wind shocks or supernova blast waves, and appears to have been formed by the interaction of the cluster with the hii region of rcw 49, a large, luminous nebula near the cluster. using the same technique as the infrared array camera on the _ spitzer space telescope, we
shock waves have been observed in a wide range of environments outside the earth, from the solar wind to the hot gas in galaxy clusters.   however, the mechanism whereby the gas in these environments is shocked has been poorly understood. here   we review the current understanding of the mechanism of shock dissipation in non - relativistic collisionless plasmas, which are defined by the relative value of the shock speed compared to the upstream sound speed and alfvn speed. for fast - mode shocks,   the critical magnetosonic magnetic field number ( mach number ) is estimated to be about 1.5 times larger than the mass - proportional value predicted by the rankine - hugoniot jump conditions. for subcritical shocks, the critical mach number is about 2.5 orders of magnitude higher than that for quasi - perpendicular shocks. using density functional theory ( dft )  , we show that the formation of subshocks is not due to direct particle collisions, but rather to collective interactions between the charged plasma and the magnetic field. at the shock front, the kinetic energy of the inflowing gas is dissipated within this fluid via collective interactions among the particles and magnetic field, transferring energy from the magnetic
we present detailed calculations of the conductance of ferromagnetic atomic contacts of fe, co, and ni using a realistic tight - binding model.   we show that for a few - atom contact of the three materials one can draw the following general conclusions : ( i ) there is no conductance quantization, mainly due to the partially open conduction channels of the minority spin electrons, ( ii ) the last plateau has typically a conductance above @xmath1, ( iii ) the current is not fully spin - polarized, and both spin species contribute to the transport.
we study the size of a collection of simple closed curves on a closed, orientable hyperbolic surface of genus @xmath5 which fill the surface and pairwise intersect at most @x Math6 times for some fixed @x math7.   we give upper and lower bounds on the minimum numbers of curves in such a collection.
the fact that supply and demand fluctuations have long - memory raises an apparent paradox about compatibility with market efficiency.   the adage that buying drives the price up and selling drives it down is one of the least controversial statements in finance. from an empirical point of view   it is clear that this is not the case, since price movements are essentially uncorrelated. here   we review two original papers on this subject by bouchaud, kockelkoren and potters ( @xcite ) and lillo and farmer ( @xfite ), which offer different views on how to reconcile the efficiency paradox. in the first paper   they show that the price response to transactions of the same size is highly variable, and that in price formation liquidity fluctuations dominate over fluctuations in transaction size. under their assumptions, to cancel out the inefficiency caused by the short - memory of transactions the sum of all the bare propagators associated with each transaction   has to go to zero. for the second paper they suggest that this problem can be explained in terms of permanent price impacts whose size depends on liquidity, where liquidity is defined as the price reaction to a transaction of a given size. using this perspective we show that
we investigate the effects of vector leptons in the higgs triplet model ( htm ) on the decay rate of the standard model ( sm ) higgs - like scalar at the lhc.   we find that the addition of additional vector fermions in the model enhances the di - photon decay rate by as much as 50%, while keeping new particle masses above 100 gev and preserving vacuum stability conditions. for the case where the doublet and triplet neutral higgs fields mix considerably,   the effect is even more pronounced, with the rate being enhanced by up to 50%. however, for the cases where the field mixes considerably, the rate is not significantly enhanced. a further test of the sm is the correlation of the decay@xmath1 with one for @xmath10, and the prediction of the vector lepton effect on branching ratio of @x math1.
differential positivity is a generalization of perron - frobenius theorem, which guarantees the existence of a dominant ( largest ) real eigenvalue for a linear system whose associated eigenvector is an attractor for the linear system.   the main results of differential positivity are that the trajectories of a differentially positive system either converge asymptotically to the image of an integral curve of the perron-frobenius vector field, or they move transversally to the same vector field. in the former case,   this attractor is either a collection of fixed points and connecting arcs or a limit cycle ; in the latter case, it defines a direction of maximal sensitivity. here  , we show that the converse theorem can be extended to the special case of hyperbolic attractors, i.e. a smooth dynamical system is ( strictly ) differentiallypositive in the basin of attraction of a one - dimensional normally hyperbolus compact attractor if its linearization along any given trajectory is positive.
the solar system dust cloud is an important component of space plasmas and the properties of dust and plasma are coupled through different processes.   the presence of dust particles in the plasma can lead to heating, cooling, and mass loading or unloading. most of our understanding of the dust plasma interactions in space is derived from theory ; however, laboratory measurements provide only limited information about the interactions of dust with the solar wind. in this review   we will give an overview of the solar system Dust cloud and the different observations of dust. in section ( 2 ) we will describe the different interactions of nano dust in the solar winds. in sections ( 3 ) and 4 we will discuss the dynamics and fluxes of nanodust in the sun s solar wind as well as the mechanisms of its interaction with the other solar system particles. in conclusion  , we will summarize the current knowledge of the interactions between solar systemDust and plasma in situ measurements from spacecraft.
edge localised modes ( elms ) are bursty, quasi - periodic expulsions of energy and particles from the plasma edge in the high - confinement state of toroidal magnetised plasmas.   the ideal ballooning instability with nonlinear phases or aftermath has provided a paradigm for recent and current study of the elm phenomenon theoretically. here   we present nonlinear gyrofluid computations of edge localised blowout events localised to the edge / scrape - off layer region of a tokamak plasma, where the ideal magnetic field is in the " h - mode " state of the plasma at the edge pedestal and the peak energy fluxes are generated by the onset of a potential energy release from the edge when a threshold pressure gradient is reached in the steep edge pedestals. using a combination of both global and ion gyroradius scales, we show that the ideal mhd interchange growth rate is comparable to the parallel alfvn transit time, which is fast with respect to magneto - hydrodynamic ( mhd ) but not to microturbulence. on the other hand, the acceleration of the transition from the l - to - h mode is much slower than
the modified nonlinear schrdinger ( mnls ) equation is used to derive the mean - square displacement fluctuation for the modified nls soliton propagating in a fibre.   the results show that the gordon - haus effect can be suppressed by properly adjusting the soliton / fibre parameters, without making use of external means.
embedded star clusters are characterized by the presence of stellar and sub - stellar objects in the same region of the sky as the cluster members.   they are often found in clusters of ages @xmath2 y, and the initial mass function ( imf ) of these clusters is likely to hold important clues to the questions related to the origin and early evolution of stellar clusters. with the 3 - 6@xmath6/p3.5 infrared ( ir ) camera aboard the infrared space observatory ( isocam ), we have obtained a better understanding of the nature of the ir - excess population of young stellar objects ( ysos ) in embedded clusters, and have improved the luminosity functions of these objects based on the ir excess criterion. using these new data,   we have shown that the number of embedded clusters has increased by almost a factor of 2 in the r corona australis region, the serpens cloud, the chamaeleon dark clouds, the ophiuchi cloud, and several other regions. from these results   it can be concluded that the most common type of embedded cluster is a cluster of brown dwarfs with circumstellar disks, and that the majority of the
projected entangled pair states ( peps ) describe correlated many - body systems by associating a local tensor to each site which builds up the entanglement in the wavefunction through auxiliary indices.   peps models form a versatile framework for the study of correlated quantum systems, where the physics is encoded in a tensor which gives rise to a local hamiltonian and a ground state wavefunction on the same footing. within this framework,   the key problem is to understand how the local properties of the tensor determine the global properties, i.e., quantum order, of the wavefunctions. here  , we show that long - range order can be understood in terms of symmetry breaking in the so - called transfer operator, and that the symmetry broken states can be used to determine the spontaneous magnetization.
the purpose of the present paper is to study some currently important cosmological issues such as phantom divide line crossing, avoiding singularities by realization of the bouncing solutions and the stability of these solutions in a non - minimally coupled scalar field model of universe in jordan and einstein frames and in the spirit of dark energy model.   we analyze the parameter space of the model numerically to show that which frame allows for stability of the solutions in the separate regions of the @xmath4 phase - plane. using the jordan frame, we show that crossing of the phantom Divide Line can be realized just in the j Jordan frame. by transforming to einstein s frame,   it is shown that this model can not account for crossing of cross - sectional dividing line. also, we demonstrate that the bouncing solution of the dark energy equation of state in the einstein frame is not stable in the same region of the@x math4 phase- plane as the bounced solution in thejordan frame. on the other hand, we find that the existence of bouncing solutions could be explained by the non - minimal coupling between scalar fields and gravity in the light of the current evidences from supernova searches data
the sub - mjy population of faint radio sources is a new population of galaxies which do not show up at higher flux density levels than classical radio galaxies ( @xmath2 jy ), and are relatively rare in the local universe.   the nature of this population is still not clear because of the difficulty of obtaining optical photometry and spectra for complete radio samples. here   we report the results of a comprehensive study of the sub-mjy ( ~1.5 deg@xmath13 at 1.4 ghz ) sample of the hubble deep field @xcite from the australia telescope eso slice project ( atesp,@xcite ).    the majority of the spectra are found to be dominated by early type galaxies ( 60% ), with the exception of starbursts and post - starburst galaxies, where they make up 39% of the whole sample. however, most of the rest of the spectrum is dominated by active star forming galaxies ( > 32% ) and quiescent galaxies ( < 21% ).
in their original study on the bouchaud - mzard(bm ) model on a complex network@xcite, bouchedaud and mzards carried out numerical simulations on a regular random graph to estimate the exponent of the power - law behavior.   they reported that the exponent obtained from the numerical simulation becomes smaller than that obtained from mean - field theory. in this paper, we propose a quantitative theory of the bm model for a random network using adiabatic and independent assumptions on the stationary distribution function. by using these assumptions and the central limit theorem  , we analyze the equations that determine the stationary distributions of normalized wealth in the non - wealth - condensate phase. by comparing our analytic results with those of the numerical simulations, we found that our theory showed better agreement than did the mean-field theory.
we have recently discovered fortnightly phase oscillations in the pulse timings of the hot subdwarf b ( sdb ) star cs 1246 via the minus calculated ( o - c ) diagram constructed from the radial velocity ( rv ) measurements.   an orbiting body with minimum mass of 0.13 m@xmath4 provided the simplest explanation for the phase wobble, but since no secondary light could be detected from the system, this hypothesis remained unconfirmed. here, we present corroborating radial velocity evidence for a binary companion around cs 12 46 using the light - travel time ( ltt ) technique. by using the 0.41-m prompt array, we aggressively monitored the pulsations ofcs 1246 for four consecutive months in 2010 to look for secular variations in the pulses.    we found a parabolic secular trend with overlying sine wave in the 371.7-s pulsation mode of the star. 	 the sinusoidal trend was explained by a secular decrease in the pulsational period on the order of 1 ms every 1.7 years. as each member in the system orbits the barycenter, the line - of - sight distance from it to the earth changes
the bright / hard state is a transition between the low / hard and the high / soft states ofactic black hole candidates ( bhcs ).   it is well known that the electron temperature of an accretion disk emitting hard x - rays decreases as the luminosity increases in the bright /Hard state. here  , we present a model explaining the transition from the " bright / slow " state to the " hard " state via the very high / steep power law ( vh / spl ) state during the transition. using the concept of phenomenological @xmath19-viscosity, we show that the energy transfer rate from protons to electrons via coulomb collisions balances the radiative cooling rate of inverse compton scattering in the dark / fast transition. by contrast, the heating rate from ions to electrons depends on the heat advection terms for ions in the light / dark state and the fraction of heating to electrons in the hot / cold state. when the ion temperature is lower than that of the electrons in both states, the system switches to the hard / soft state at the same time.
we are undertaking a new survey for pulsars along the galactic plane at 1.4 ghz, using the 13-element multibeam receiver recently installed on the 64-m parkes radiotelescope.   we have discovered 513 new pulsars, and have detected 190 known pulsars. to date   eight of the newly discovered pulsars are young pulsars ( @xmath5 = 10@xmath7 years ), and two radio pulsars with the highest known surface magnetic field have been discovered.
a systematic study of leptonic four fermion final states at a @xmath0 collider is presented.   the cross section for the process @x Math7 is computed using a new technique which, in collaboration with _   f. caravaglios_ @xcite, i have recently developed. exploiting the relation between the one - particle irreducible green functions generator @x math9 and the connected greenfunctions generator@xmath10 we have proposed a simple numerical algorithm to compute tree level scattering amplitudes. here   i describe the implementation of the algorithm in a fortran code alpha which currently uses the standard electroweak lagrangian and can compute any scattering amplitude in this framework, in a fully automatic way.
the quasar pmn  j01340931 is a strong gravitational lens galaxy with a unique radio morphology consisting of six compact components within a circle of diameter. in a companion paper, keeton & winn ( 2003 ; hereafter, kw03 ) present the first quantitative models that explain all the previously known properties of. in those models,   five of the radio components are multiple images of a single quasar, and the sixth component represents a different source, which is presumably a second component of the same background radio source. in this paper   we present multi - frequency observations of  with the very long baseline array and the hubble space telescope that confirm some of these predictions, and refute none of them.
the accretion disk of catastaclysmic variables ( cvs ) is currently believed to have a fairly complex structure.   however, the one - dimensional emission line profiles obtained with a high spectral resolution during one or more complete orbital observations of a white dwarf ( wd ) and a red dwarf ( secondary ) in a binary at a late evolutionary stage are still poorly understood. here  , we use doppler tomography to study the emission lines of the accreting gas stream and the accreted matter around the wd at weak and intermediate wd magnetic fields. using the well - known theoretical stellar mass - radius relation, we show that the accretion disks of cvs can be classified as polar or intermediate polar depending on the magnetic field strength and the ratio of the secondary to the primary. for a period of @xmath7,   the observed emission lines are consistent with the predictions of numerical gasdynamic calculations, which predict the formation of a precessional density wave in the inner disk that is almost stationary relative to a remote observer. for an accretion rate of ~1.5 times that of the primary, the intensity of the density wave is about 1.2 times higher than
we extend the finite - size scaling ( fss ) analysis to first - order quantum transitions ( foqts ) driven by temperature - like parameters, with a discontinuity in the infinite - volume energy density of the ground state.   for this purpose we consider the quantum @xmath0-state potts chains  @xcite, which undergo foqtts for a sufficiently large number of states, i.e.@xmath1  @excite. using the general ansatzes  and , we show that the asymptotic size dependence of the scaling variables around the transition point is particularly sensitive to the choice of the boundary conditions, giving rise to size dependences with different power laws. at the ferromagnetic phase of the ising chains  , where the transition is driven by a magnetic field coupled to the order - parameter spin operator, we observe an exponential size dependence for open and periodic boundary conditions ; however, it is power law for antiperiodic or kink - like boundary conditions. here   we further extend the fss analysis to thermal - like Foqts driven by ( even ) temperature
radio astronomy is making a comeback at the sub - millijansky level.   the focus of this paper is long duration radio transients of extra - galactic origin. in 2007,   bower et al. reported on the analysis of a single field observed every week as a part of the very large array calibration program ( b07 ; @xcite ) and found eight transients found in only one epoch ( hereafter " single - epoch " ; duration, 20minutes @xmath6 1week ) and two transient found in rolling 2-month searches ( hereafter, " multi - epoch" sources ).. the most remarkable feature of the b07 sources is an absence of optical and near - ir counterparts, despite deep searches ( b06 ; @xaite ). as noted by @xcites, all extra - Galactic transients have detectable optical counterparts, namely, their host galaxies.    the present paper discusses the current state of knowledge about the location and duration of these transients.
the spatiotemporal dynamics of the interband dipole in semiconductor lasers can be simulated successfully by semiclassical maxwell - bloch equations without including any quantum effects in the light field.   however, the incoherent noise required by the uncertainty principle in both the electrical dipole of the semiconductor medium and the lightfield itself is of significant importance when several cavity modes compete or when the laser is close to threshold. in this paper  , we present an alternative approach to the problem of the spatial coherence of spontaneous emission and amplified spontaneous emission in such devices which is based on maxwell-bloch equations. by including these properties in the maxwell s equations,   non - markovian terms are avoided and the quantum mechanical equations may be integrated in a straightforward manner.
the design luminosity of large hadron collider ( lhc ) strip trackers will be increased by a factor of ten over the next decade.   this increase means that the innermost layers of the detector will require an order of magnitude improvement in radiation hardness over what is presently in use. for this purpose, the sibt group has been studying the use of magnetic czochralski ( mcz ) silicon as a potential replacement for the float zone ( fz ) silicon that is presently used in the cms strip tracker. using a cold box developed by the vienna hep group for long - term testing of cms silicon strip modules and a modified cms daq system, we have measured the radiation hardness of the new sensor material @xcite with respect to the current float zone silicon from the cern sps h2 beam using a range of different ionic fluences at the same time points on the beam pipe. here   we describe the experimental design and construction of a 10- slot vienna box based on the x - ray beam telescope used to test the suitability of the proposed technology for the design of a new strip tracker module.
time travel is a phenomenon which has been attracting interest both in fiction and general discussions for a long time.   however, only after a formulation of the theory of relativity such considerations could be investigated on a more scientific and solid basis. here   we review the studies of spacetimes with closed timelike curves ( ctcs ) during the 1980s and the 1990s and show that they are not necessarily causally pathological. to prove this we consider a system of interacting particles in spacetime with well known local physical laws ( e.g., a particle or an electromagnetic field ) and we require that the local laws hold locally in any small spacetime domain. as a consequence  , we also require a globally consistent solution of local laws. if these local laws have no globally consistent solutions, the spacetime would be clearly pathological and we could rule it out from our consideration. instead, we show that for a simple physical system pathology is not so severe and the equations of motion can be consistently solved.
we investigate the effects of three - particle collisions on the thermopower and conductance of clean one - dimensional ( 1d ) mesoscopic wires.   we show that the number of left- and right - moving particles in a wire has to change in a scattering event for the current to change, and that this change is dependent on the temperature of the electron reservoirs. using the boltzmann equation, we calculate the main ingredient for our perturbation theory, namely the three -particle matrix element and scattering rate using a @xmath5-matrix expansion. as a measurable quantity,   the temperature dependence of the thermal power required to counteract a current due to the temperature difference is found to be very sensitive to the amount of electron - electron interaction.
woven graph codes are a class of generalized graph - based codes with constituent block codes whose block length is a multiple of the graph degree.   we consider first woven graph codes with constituents @xmath11 block codes and we derive a product - type lower bound on the minimum distance of such codes. in order to analyze their asymptotic performances, we modify the approach used in @xcite to @x Math0-partite, @x math0-uniform hypergraphs and constituent @x maths11 block code. it is shown that when the block length of the constituent blocks grows to infinity in the random ensemble of woven graph coding with binary constituent blockcodes, then there exist codes satisfying the product - types lower bound for the minimum distances of such coded blocks. also, we generalize the analysis to woven graph code with constituent convolutional codes by considering a sequence of zero - tail ( zt ) terminated convolved codes of increasing block length @xMath9 and we find codes satisfying costello lower bounds on the free distance of these codes.
the thermoelectric response of molecular junctions is well understood within a linear response formulation of the thermopower.   however, the applied temperature differences can be tens of degrees kelvin, i.e. larger than the dot - lead coupling energy. in the present work, we use a variational form of the lang - firsov transformation to determine the thermovoltage for a given temperature bias by minimizing the thermally induced charge current. using the anderson - holstein model, we show that the calculated thermopowers are in good agreement with the experimental results.
in the present study we investigate the effectiveness of monte - carlo algorithms, widely employed for simulations in lattice qft and spin models, on gpu and to investigate their effectiveness on such parallel systems @xcite-@xcite.   we firstly implement existing local algorithms, the metropolis and the heat - bath algorithms, on ati rv770 graphics processors ( gpus ) using ati stream sdk and then compare their performance results with those of a non - local algorithm, the worm algorithm, which is based on utilization of nvidia s cuda toolkit while ati programming environment seems to be less popular in the literature. as an illustrative example  , we show that the performance of @xmath3 ising model simulations for metropolis algorithm is about 1 tflops higher than that of @Xmath1 gluodynamics simulations for heat - water algorithm. by comparing the results of these two simulations, we find that both algorithms are more efficient compared to the other one.
the computer revolution has provided scholars with a huge amount of data and computational resources to process and analyze these data.   the size of real networks one can potentially handle has also grown considerably, reaching millions or even billions of vertices. in order to deal with such a large number of units,   graph analysis has become crucial to understand the features of networked systems. in this review  , we discuss the concept of communities, also called clusters or modules, which are groups of vertice which probably share common properties and/or play similar roles within the graph. for instance, clustering web clients who have similar interests and are geografically near to each other may improve the performance of services provided on the world wide web, in that each cluster of clients could be served by a dedicated mirror server. identifying clusters of customers with similar interests in the network of purchase relationships between customers and products of online retailers ( like, e.g., www.amazon.com ) enables to set up efficient recommendation systems that better guide customers through the list of items of the goods of the retailer and enhance the business opportunities.
the observed cosmic speed up @xcite questions the validity of general relativity ( gr ) on large scales.   in fact, if on one hand the model of gravitational interaction as described by einstein s theory is in agreement with many observational tests on relatively small scales, as solar system and binary pulsars observations show, then it is well known that in order to make gr agree with the observed acceleration of the universe the existence of _ dark energy _, a cosmic fluid having exotic properties, has been postulated. in this context  , we want to consider here a generalization of e Einstein s theory, the so - called rastall s model, which is based on the requirement that the stress - energy tensor for the matter / energy content is not conserved, i.e. @xmath0. since the original theory was introduced more than 30 years ago, it is interesting to test it against the recent cosmological data, by investigating the conditions that the parameters of the theory have to fulfill in orderto reproduce the data. in particular, we focus on the possibility of describing the accelerated expansion of the cosmos in rast all s framework, by comparing the results with the cardassians expansion model
the quantum impurities embedded in superconducting host materials have been the topic of intensive studies for about 50 years.   early interests predominantly explored in what way the impurities affect the superconditions of the bulk materials, i.e. the anderson theorem or the paramagnetic effect on the isotropic superconductors. here   we present a systematic study of the in - gap andreev states originating from the spin scattering either on the magnetic or non - magnetic quantum impurity ( quantum dot ) connected to the super conductive electrodes. using the nanoscopic tunneling junctions where the quantum dots are placed between one superconducted ( s ) and another normal ( n ) electrode, we show that the quantum dot pair - breaking character of the electron scattering is mainly due to the induced on - dot pairing. at low temperatures   the coulomb blockade and the kondo singlet state also play a role.
inflation, or gauge inflation, is the theory of a period of accelerated expansion of the universe which occurs when one or more scalar fields, the inflaton fields, dominate the energy density of the cosmological universe with their potential being overwhelming.   the slow - roll condition of natural inflation says that an inflaton field with a fully radiatively generated flat potential should be very small compared with the inflationary hubble parameter. in this paper, we try to build the minimal model of gauge inflation using the simplest orbifold and the minimal non - abelian gauge group for the hidden sector. by taking the hidden sectors gauge interaction, the theory is less constrained than the visible sector gauge theory, e.g. grand unification theory ( gut ), and the minimality can apply to the particle contents. as a result, the gauge inflation model is able to take into account the existence of a massless scalar boson from a part of the fifth component of the gauge boson in five dimensional bulk with a flat potential and the gauge invariant wilson line, i.e. the gauge coupling constant. under such a condition, the rate constants of the curvature perturbation are much smaller than
the neutrino - nucleon cross section is a crucial parameter in the calculation of attenuation of neutrinos traversing the earth and the event rate in high energy neutrini telescopes.   it provides a probe of quantum chromodynamics in the kinematic region of very small values of bjorken-@xmath4, which implies that for @xmath6 gev one has @x Math7 at @x math8 gev@x maths9.    the description of quantumchromodynamics dynamics in the high energy limit still is a subject of intense debate.. theoretically, at high energies ( small bjorkshyn-@Xmath4 ) one expects the transition of the regime described by the linear dynamics to a new regime where the physical process of recombination of partons becomes important in the parton cascade and the evolution is given by a non - linear evolution equation., this regime is characterized by the limitation on the maximum phase - space parton density that can be reached in the hadron wavefunction ( parton saturation ), with the transition being specified by a typical scale, which is energy dependent and is called saturation scale. 	 experimentally, possible signals
the superconducting order parameter in the hybrid ruthenate - cuprate superconductor rusr@xmath3gdcu@x Math3o@x math4 ( ru-1212 ) is studied by point - contact spectroscopy.   the results show that the super conductance curves of the Ru-12 compounds are characterized by a symmetry of the ferromagnetic order parameter @xmath2-wave, which is in good agreement with the experimental conductance profiles. as in the other cuprates,   superconductivity inRu-12 is due to singlet cooper pairs.
the electronic structure of silicon nanowires  ( sinws ) grown from a crystalline bulk core  @xcite  is studied in the framework of density - functional theory.   the influence of the reconstruction of the lateral surface on the electronic structure and the localisation of the surface states that have been found to form are discussed. for very thin one - dimensional structures such as those that we are treating, the predictions of wulff s rule should be carefully revised by considering the size of the vicinal surfaces at the edges of the sinw and the shape of the cross - sectional section.
modified newtonian dynamics ( mond ) is an alternative to dark matter for the prediction of the rotation curves of spiral galaxies.   it has long been known that the theory predicts more matter than is observed in clusters of galaxies, but this discrepancy is not formally a falsification of mond. here   we show that the magnitude of the discrepancy between the predicted and observed rotation curves depends on the mass - to - light ratio ( m / l ) of the stellar disk, which is proportional to the square root of the effective gravitational force at accelerations below a critical value, @xmath0, and the number of stars in the galaxy. using the mond prescription, we find that the m / ls of the observed rotation curve are significantly different from those predicted by mond, i.e., about 1.5 times larger than the actual size of the star population. however, the difference is not due to the use of the rotated rotation curve as a tracer of the gravitational force or to the existence of additional undetected matter in the form of dissipationless matter. instead, the discrepancy is caused by the fact that the rotation curve is too small to be consistent with the observed mass distribution,
we study a  model of a local pair superconductor with on - site electron pairing in a  lattice @xcite.   the model is considered as a generalization of the hamiltonian (  ) model, which is a special xy - model with a  single ion anisotropy in a transverse field ( in the @xmath11-direction ) and corresponds to the external magnetic field. for the atomistic analysis we consider the interaction parameters of the model : ( i ) the intersite pair hopping interaction@xmath1, determining the electron pair mobility and responsible for the long - range superconducting order in the system and ( ii ) the on -Site density - density interaction@Xmath0, which contributes ( together with @x Math1 ) to the pair binding energy by reducing ( ) or enhancing ( ) its value.    the results show that the model can be considered as relatively simple, effective model of such a supercond conductor with local electron pairing. moreover  , the knowledge of the limit can be used as starting point for a perturbation expansion in powers of the hopping @x math14 and provides a benchmark for various
the metal - insulator transition arising from the competition of randomness and interactions remains an intriguing problem in condensed matter physics.   the commonly cited qualitative picture of the appearence of a metallic phase out of a disordered one is that the interactions act to screen the one - body potential. here   we present results for the conductivity and renormalized site energy of the two dimensional anderson - hubbard model using the determinant quantum monte carlo ( dqmc ) method. while increasing @xmath0 can drive an anderson insulating phase metallic, there appears to be no sharp signature of this transition in the variance of the renormalization site energies. by comparing the obtained results with experimental data, we show that the metallic phase arises at least partially from an additional mechanism beyond a simple screening of the one-body potential.
high mass star formation is a process that has been well studied and characterized based in part on the high resolution observations possible towards the closest examples of low mass star forming regions.   we present follow - up observations using the james clerk maxwell telescope to seven regions previously known to have hii regions @xcite and molecular outflows as traced by sio emission or cs@xcite or co @xmath0 lines, and show that, of 23 regions with ongoing outflow activity ( 14 sources ), half ( seven ) showed evidence for large scale infall motion as well as large scale outflowing gas shock, suggesting that the accreting protostar may still be accreating material. however, with single pointing observations, we could not determine the sizes of the infra - red regions or the size of the outflowed gas shock regions. here  , we present an alternative evolutionary sequence for the formation of high mass stars, which suggests that they may form via the accretion of matter onto a single object in a manner similar to their lower mass counterparts.
the primordial scenario of globular cluster ( gc ) formation was first proposed by @xcite and colleagues in @xmath1, where gcs are proposed to have formed in the potential wells of dark matter minihalos in the early universe.   it is often assumed that the very first stellar objects produced enough lyman - werner photons ( capable of dissolving h@xmath5 molecules, which are the main coolant in the pristine gas ) to prohibit star formation in most of the low mass gas - rich halos, which later merged to form a dwarf galaxy. in this picture, gcs can be considered as small nucleated dwarfs accreted at some point by larger galaxies, which lose their extra - nuclear material ( baryons and dark matter ) due to stripping by the tidal forces of the accreting galaxy. here   we suggest that this model is fully consistent with the current view of gc formation.
we investigate the effect of uncertainty in using different spectral models which determine the spectral peak energy ( @xmath0 ) of gamma - ray bursts ( grbs ) on the, and correlations using our database developed in @xcite.   we examine this model bias by dividing the samples into two data sets as gold and bronze according to the quality of spectral observation. for the gold data set, we use the cutoff power - law ( cpl ) model with three free parameters to fit the spectra of 109 grbs with known redshift and well - determined spectral parameters such as 1-second peak luminosity, and isotropic energy. from the data, we find that the systematic difference between the peak energies fitted by the band model and the ones fitting by the cpl model is systematically larger than the true value of @x math0.1 so that the results of the correlation are systematically harder than those of the previous studies.    we also find that there is a systematic bias in the mean values of the correlations between the measured and estimated values of @Xmath0.2 and @x Math0.3 when the signal - to - noise ratio is high enough.
many body perturbation theory ( mbpt ) diagrammatic approaches offer a path to the solution of the quantum many body problem of solids, which complements alternative methods such as qmc ( quantum monte carlo ) and cc ( couple cluster ).   this approach received attention for over half a century but there is no complete understanding of how different selection of diagrams perform for different physical quantities. in this work   we investigate these questions in the framework of the homogeneous electron gas ( heg ) in a neutralizing positively charged background. using self consistent ( sc ) method @xcite we solve the hedin s equations self - consistently using different approximations for the three point three - point screened interaction, the four - point irreducible interaction and the polarizability of the heg in terms of g and w. we study the relative importance of different diagrams for the polarization and the self energy with respect to the self - consistency in the green s function and the vertex corrections in the self-consistently self - consistent ( renormalized ) green function.
we present predictions for the simplest and most useful statistical quantifiers of galaxy voids in a cold dark matter universe using a combination of n - body simulations of dark matter and semi - analytical modelling of galaxy formation.   we show that the properties of voids and the galaxies which live within them can be quite different from those of the dark matter, and that the distributions of these voids are biased by the presence of some galaxies which are biased tracers of the light source.
circumnuclear starbursts ( agns ) are rare events that occur in active galaxies.   they are thought to be associated with the formation of a super massive black hole ( agn ) around the galaxy, which then triggers a starburst. here   we investigate the frequency of such coincidences by comparing the emission signatures of young stars in the ultraviolet spectra of two seyfert 2 galaxies with those of a large number of small accretors in an agn. for both galaxies,   the spectrum of the active nucleus shows strong caii triplet absorption at @xmath3, suggesting that the starburst - induced enhancement of the activity of the stellar population in front of it is a major component of the observed uv flux. however, only one of the two galaxies has been found to show a strong starburst signature in the uv spectra and no starburst was detected in the spectra from the other. using a new method to search for starburst signatures in the visible spectrum of these galaxies, we find that the most frequent starburst co - occurrence occurs in the early stages of star formation, when the average age of the accretor population is about 1.5
electronic mach - zehnder interferometer ( mzi ) @xcite can be realized with the edge states of the quantum hall liquids ( qhls ).   together with the quantum antidots, mzis in the regime of the fractional quantum hall effect ( fqhe ) are expected to be useful for observation of the fractionsal statistics of anyonic quasiparticles. in this work,   we follow the approach to the mzi that allows us to obtain the uniform description of its transport properties in both regimes of electron and Quasiparticle tunneling. 	 we consider the standard mzi geometry with two tunneling contacts between the two effectively parallel edges of qhl, but allow for, in general, different filling factors,@xmath0, with @xmath1, of these edges. in the symmetric case of equal propagation times along the two edges between the contacts, the corresponding 1d field theory permits an exact bethe ansatz solution @xcide. making use of this solution, we calculate the zero - temperature full counting statistics @xcites of the charge transferred between the 2 edges forming mzi.. the transferred charge distribution is shown to reflect
the muon anomalous magnetic moment ( the muon @xmath1 ) anomaly indicates physics beyond the standard model ( sm ) higgs boson   @xcite.   the results of the atlas and the cms collaborations have reported observations of a new particle with a mass of about 126 gev, which is considered to be the current standard model higgsboson @xcite ; if the particle is indeed the higgens boson, the sm inevitably involves the hierarchy problem. in this letter  , we investigate the lhc signatures assuming the mass hierarchy of the superparticles, with particular attention to the muons @x math1 and @x Math2.    we find that the direct searches at the lHc for the super Particles are not always promising, because the particles can be away from the l hc reach without diminishing the utility of the supersymmetry as a solution to themuon @Xmath1 anomaly. 	 we examine the direct productions of the Superparticles which are relevant for the muone @x maths1 anomaly, and show that these searches are particularly important in the parameter regions where the mu on @xMath1
the formation of diffuse radio regions ( radio halos or relics ) detected so far in a limited number of clusters of galaxies seems due to large - scale shocks and turbulence associated to gravitational mergers of subclusters and groups able to provide the necessary ingredients, namely, magnetic field amplification and particle reacceleration.   the existence of these radio regions could be related to the origin of hard x - ray ( hxr ) emission which has been detected in a few clusters thanks to the sensitivity and wide spectral coverage of the /phoswich detection system ( pds ). in this letter   we present the combined pds spectrum of abell 2256 obtained by summing the spectrum of a second long observation of @xmath2 300 ks with that of the previous shorter observation of ~130 ks. both observations both confirm the presence of non - thermal radiation from the cluster in excess of the thermal emission measured by the medium - energy concentrator / spectrometer ( mecs ) in the energy range@xmath22 - 10 kev.    the results of these detections have been challenged by the data analysis of rossetti & molendi ( 2004 ; thereafter rm04 ).
we study the behavior of monte carlo ( mc ) simulations in terms of ergodic behavior.   we find that ergodicity is achieved when the simulation length is sufficiently long to sample configuration space appropriately. for systems with multiple time scales,   er godicity is reached when every region with non - negligible probability has been sampled by the simulation.
we present the first results of a deep survey of the super star cluster ngc2070, at the centre of the 30doradus nebula in the large magellanic cloud ( otherwise known as the tarantula nebula ), using the wide field camera 3 ( wfc3 ) camera.   we show that the cluster contains a significant population of fainter, low mass main sequence ( ms ) and pre - ms ( pms ) stars and brown dwarfs, but the precise nature of their spatial and mass distributions is not well understood. with its high spatial resolution over a wide field encompassing most of the central part of the cluster and its unprecedented sensitivity in the near uv and ir, the wfc4 camera allows us to tackle for the first time many of the problems summarised above with some hope of resolving them.
in this work we study the ( real ) eigenfunctions of the laplace - beltrami operator on a riemannian surface with dirichlet boundary conditions.   we propose a new method for the classification of billiards according to their classical properties, which is different from the more common spectral and wavefunction analysis. in order to interrogate the morphology of nodal lines, we consider the nodal count of the  eigenfunction of the eigenstate of a domain, and its nodal domains sequence. by using the area - to - perimeter ratio as a parameter  , we can distinguish between the distributions of nodals in domains where the underlying classical dynamics is integrable ( separable ) or chaotic ( chaotic ). for separable domains,   our method provides yet another test to the conjectures by berry and bogomolny.
we consider the temperature dependence of resistivity due to scattering of conducting electrons by domain wall fluctuations in broadened metamagnetic first order phase transition.   we consider a three dimensional metallic metamagnet where@xmath0 electrons are considered to be conducting, and @xmath1 electrons responsible for the magnetic state. at temperatures larger than inverse spin relaxation time resistance due to electron scattering by spin fluctuations   is strongly deviates from fermi liquid quadratic dependence. while this temperature dependence coincides with that due the volume spin - fluctuations, it starts at much lower temperature..@xcite in this case the interaction correction to conductivity has temperature dependence predicted for the 2d volume spin fluctuations.
we investigate the effects of berry corrections on the bloch oscillations in one - dimensional ( 1d ) time - dependent parity breaking potentials.   in particular, we consider the dynamics of a non interacting wave packet in a 1d periodic potential, in the presence of an additional constant force, as can be obtained for instance with ultracold atoms in an optical lattice subjected to gravity. by direct comparison with the full solution of the schrdinger equation,   we show that these corrections of the semiclassical equations fully account for the center of mass dynamics of the wavepacket and that the anomalous effects of the corrections depend on the degree of parity breaking of the potential and on modulation parameters. from time - of - flight measurements in current experiments with non - interacting bose - einstein condensates in optical lattices, we find that the influence of the anomalously occurring velocity term on bloch frequency is more pronounced in the case of time - modulations than in the static case.
the structure of massless brst cohomology in flat space is more or less clear, but it appears that it has never been explicitly spelled out in the literature.   the present paper is aimed at filling this gap. for the closed _   bosonic _ string the cohomological problem was computed in @xcite. for a pure spinor superstring,   we do a similar computation in @xmath1 without taking into account ( /@xmath2 ). to defeat the ghost number three cohomologies, we need to take into account the existence of the dilaton superfield and the presence of nonphysical vertex operators. using the composite @x math4-ghost, we show that the density of the spectra of the type iib supergravity is in one - to - one correspondence with two - dimensional sigma - models satisfying certain axioms such as the action of the susy maxwell operator on the spacetime of solutions of the types iibvsmaxwell equations.
the @xmath2-radiation from remote cosmic sources at high galactic latitudes has been used to infer the diffuse near - infrared background radiation, which is difficult to observe directly.   macminn & primack ( @xcite ) have recently proposed a model of the evolution of the diffuse background photon density based on the well - understood physics of pair production. in this article  , we discuss the implications of this model for our understanding of the origin of the @x Math2-ray emission from blazars.
self - avoiding polymerized membranes have attracted considerable interest from the point of view of basic research in recent years.   their static properties have been studied analytically and numerically, but the membrane dynamics is less well - understood. in the present work   we employ an efficient off - lattice monte carlo algorithm, focusing on the subdiffusive dynamics of self - avoiding tethered membranes and comparing some of the salient dynamic features to those of linear polymers. as a step forward, however, we suggest a scaling theory which explains our findings for the anomalous membrane dynamics, relating the observed values of @xmath8 to the specific stochastic motion of particular groups of sheet segments.
the scattering length @xmath1 is a simple parameter that characterizes the contact - like pseudo - potential approximation of the van der waals potential at the strength of dysprosium ( dy ) s dipole moment.   this number encapsulates the essential physics needed to predict the cross section of atoms whose collision channel is dominated by an@xmath0 partial wave.  in contrast to the short - ranged, isotropic van derwaals interaction, the magnetic dipole - dipole interaction ( ddi ) in ultracold bosonic dy gases is long - ranged and highly anisotropic. here  , we compare the measured cross - dimensional relaxation of an ultraacold gas of dy to numerical simulations in which the ddi s contribution to the total elastic cross section is well understood. for the first time, we show that the simulation of the nonequilibrium dynamics of ultrac old dipolar gases in realistic experimental conditions is consistent with the results of the theoretical calculations. moreover, we find that the density functional theory ( dft ) calculations are able to reproduce thenonequilibrium behavior of the studied gas in a way that accounts for the small dipolar contribution of the d diode - dip
a numerical method for solving the self - gravitating forces in cartesian and polar coordinates is proposed.   the method is of linear complexity, without artificial boundary conditions, and near second order accuracy. a comparison with several existing methods is also presented.
the relevance criterion for the critical behaviour of the ising quantum chain ( iqc ) in a transverse magnetic field is derived for a restricted class of arbitrary substitution rules for two - letter substitution chains.   the analysis is carried out in detail for two-letter substitution chains, with the result that luck s relevance criterion emerges from the renormalisation relations in a natural way. for infinite classes of substitution chains with marginal fluctuations, including the two - letters, an analytic expression for the correlation length critical exponent is given. for the most general case of @xmath4-letter replacement rules,   an extended renormalization scheme is presented and discussed for certain examples. for non - onsager - type substitution rules, the results are in accordance with luck s predictions.
the ferritin core is a good candidate for the observation of quantum tunneling of the magnetization @xcite, and various experimental studies, at low temperature, have claimed to have observed this tunneling.   the aim of the present work is to reexamine the problem of the uncompensated magnetization in ferritins, by comparing @xmath0fe mssbauer data, both in zero field and in applied magnetic fields up to 7 t, with magnetization data obtained for the same samples. by taking proper account of the crystalline anisotropy in an antiferromagnetic structure,   one obtains a coherent interpretation of the results of the two techniques.we present a new interpretation of superparamagnetic behaviour of an ensemble of randomly oriented antiferroma - like particles, in terms of a non - langevin law for the uncompENSENSED magnetisation, for applications of magnetic fields lower than the spin - flop field.
the minimum - cost integral flow problem is a well known fundamental problem in algorithms and optimization with plenty of important applications.   it is known to be @xmath7-complete even in its integral version provided that the edge capacities are exponentially large in the size of the network. here  , we present a fast randomized parallel method for detecting the existence of mutually vertex disjoint paths of bounded total length connecting two sets of @x Math0 terminals in a directed graph. by using the idea of monomial cancellation, the latter problem reduces to testing the polynomial over a finite field of characteristic two for non - identity with zero.we combine the demillo - lipton - schwartz - zippel lemma ( @xcite ) on probabilistic verification of polynomials with parallel dynamic programming to perform the test efficiently in parallel. additionally, we use the isolation lemma to construct the minimal - cost flow@xcite.
the top quark is the heaviest known elementary particle.   it has a lifetime significantly shorter than the time scale required for hadronization. due to this short lifetime, bare top quink properties   can be observed by measuring the kinematics of the top s decay products. in this paper   we present results from the top kinematic working group prepared for snowmass 2013 and from contributed studies by the lhcb collaboration. using the publicly available program mcfm  @xcite at next - to - leading order ( nlo ) qcd, we estimate theoretical uncertainties on basic kinematically distributions in top quarks pair production at the 14  and 33  tev lhc, and the same uncertainties are considered for the high @xmath10 tails of theTop quark production cross - sections.. the observability of the inclusive smtop quark charge asymmetry at the14  tevs is studied as a function of experimental systematic uncertainties.    the results are compared with the results of experiments for alternate measurements of the Top quark spin correlations at lhcs 14 and 33.
the weak lefschetz property is a well - known property of standard graded artinian algebras over a field @xmath1.   this property is of interest mainly because it constrains the hilbert function, which in turn has interesting consequences ( see, e.g., @xcite for a spectacular application ). here   we further explore level artinian monomial almost complete intersections in three variables, as discussed in @xcite,  , where three of the four parameters are equal. in particular, we consider the two cases where a parameter is extremal. using our results from these cases  , we show that all height three complete intersections over an algebraically closed field of characteristic zero have the weak lefschhetz Property, but this is still unknown if we consider height four complete intersections.
radio - quiet active galactic nuclei ( agn ) are well - established sources of doppler - boosted @xmath0-ray emission in the gev range @xcite.   the bulk of this emission is believed to originate within a few parsecs of the central black hole, but large - scale structures formed by jets outside their hosts due to interactions with the intergalactic medium may also be bright gev emitters. here  , we report the discovery of a significant @x Math 0.1100gev excess positionally coinciding with the circinus galaxy using 4 years of _ fermi	lat data and discuss possible origins for this emission.
this paper presents a post - mortem analysis of the english and spanish lexical sample tasks of senseval-2.   we compare the agreement among the competing systems using the kappa statistic and measure the degree to which they are complementary by rating the difficulty of test instances relative to the number of systems that were able to disambiguate them correctly. for the spanish task,   the most common system was uned_ls_u ( n = 23 ), followed by clr_ls ( n < 23 ) and iit2 ( n > 23 ). in the english task, there were no significant differences in the degree of agreement between the systems except for the fact that uned _ls_t was significantly more likely to be successful with many of the test instances compared to other systems ( p < 0.05 ). on the other hand, all of the systems were found to be largely in agreement with each other ( kappa = 0.71 ), but only one system was able to perform better than the other systems in all test instances ( p<0.05).the results of this study suggest that the ability to combine the performance of several systems is potentially more accurate than
we present a method for the evaluation of the phase of a phase gate based on the adiabatic elimination ( ae ) approximation.   we show that, unless applied very carefully, the ae approximation can lead to significant errors in the value of the gate phase, ranging from higher terms in the anisotropy expansion to population decay and shifts from additional states. by analyzing various sources of errors  , we find that the standard ae approximations are accurate only for very large detunings of the laser carrier frequency and the bohr transition frequency, with the latter being the limiting case for the adsorption of the far - off - resonant state(s ) into the coherent field. using this approach, we also show that it is possible to estimate the accumulated phase during a two - state quantum system interaction with a coherent field with high accuracy.
the nash equilibrium is a key concept in modern economic thought, but it is not clear how to find it efficiently.   the recent result by roger myerson @xcite establishing that the problem is ppad - complete explains why. here   we show that the tracing procedure and the homotopy method for finding nash equilibria require exponential time, and that finding the solutions they prescribe requires the power of the brouwer fixpoint that would have been discovered by the homo - topy method.
we present a new suzaku observation on iras f01475 - 0740  taken in 2008, in which we detect significant and rapid x - ray variations at time scale down to 5 ks.   such rapid variations, which were not seen during previous xmm - newton exposure, provide strong constraint to the x - rays unabsorbed nature of this galaxy.
remote state preparation ( rsp ) is a powerful method for securely transmitting a quantum state from a sender to a remote receiver by pre - shared entangled resource.   however, the existence of quantum noise severely affects the security and reliability of the system. in this paper, we investigate how to improve the efficiency of multiparticle entanglement based quantum secure communication in noisy environment using the weak measurement and its reversal measurement. taking a ghz based deterministic joint rsp ( djrsp ) scheme as an example, we utilize the technique of weak measurement with its reversal to suppress the effect of amplitude - damping noise on a bidirectional jrsp protocol. at the end of the study, we show that the strength of the weak measurements can be used to increase the success probability of the Djrsp scheme.
parton structure functions of hadrons in the bjorken limit and high enough @xmath5, as probed in inclusive deep inelastic scattering ( dis ), are traditionally considered to be the domain of perturbative qcd.   however, it is now possible to estimate the parton distribution functions of other hadrons using constituent quark models to evaluate the low energy initial condition under the assumption that the gluon and sea content of hadron vanish at the corresponding low energy resolution scale, and dynamically generate them by qcd evolution to higher @x Math5 scales.. these estimates can then be used to test the sensitivity of various experiments to the distributions of interest. here  , we show that this approach is applicable to the generalized parton distributions of the nambu  jona - lasinio model of the pion, a quark model where spontaneous breaking of chiral symmetry plays a dominant role, and to the valence and sea distributions of pseudoscalar mesons and specifically to the generalizations of the usual partonic distributions of Hadron 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
nonlinearity is a key property of discrete nonlinear schrdinger ( dnls ) equations.   the self - induced peierls - nabarro potential ( pnp ) vanishes for discrete solitons in the framework of the ablowitz - ladik ( al ) equations, but recently it was demonstrated that nonlocal nonlinearity of a more general type representing real physical systems can indeed lead to strong reduction of pnp for lattice soliton. in this paper  , we consider a class of dnlss equations featuring a general type of non linearity characterized by a nonlocal response as well as an arbitrary polynomial dependence on the intensity, that includes the case of nonlocal saturable nonlinearities and show that, under certain conditions, the pnp can be made exactly zero. quite remarkably, the corresponding equations are generally not integrable, leading to nontrivial soliton dynamics.graphical abstract
red supergiants are the most powerful stars in the universe.   they are also known as behemoths because of their large birth masses and convective nature. here   we review the current state of knowledge about the formation, evolution and behaviour of this class of stars, and discuss some of the important aspects of their behaviour that need to be better understood.
the broad - line region ( blr ) of active galactic nuclei ( agns ) is a region of gas only @xmath3pc in size and presumed to be photoionized by the emission from an accretion disk around a supermassive black hole.   echo - mapping experiments have long been used to study the blr using the technique of reverberation mapping @xcite to study its broad emission - line fluxes and profiles, which are spatially unresolvable even for the most nearby galaxies. due to the formidable requirements of long - duration monitoring, high temporal sampling, and high - quality and homogeneous data for recovery of velocity - delay maps, most echo - map experiments have restricted the analysis to a simpler problem : measuring the mean delay of the continuum - emission region at zero time delay. here  , we present velocity - Delay Maps for six optical h and he recombination lines in the lick agn monitoring project ( lamp ) spectra of arp151 ( mrk40 ) : h@xmath2, h@Xmath2 + 1, h=0, h+1 + 2, h*1 + 0.5, h&2 + 3, and
the phase diagram of qcd at zero and finite chemical potential is studied using the functional method of dyson - schwinger equations.   the influence of the charm quark @xcite on the phase diagram is investigated by comparing results for the quark condensate and the unquenched gluon propagator at zero chemical potential with results from lattice qcd. in particular, we put particular emphasis on the effects of charm quarks on the transition temperatures and the equation of state at low lhc energies.
ultracool dwarfs are relatively bright sources of radio emission at radio frequencies @xmath1 m7 @xcite despite their low bolometric luminosity.   initially, the detection of variable, broadband radio emission with low net circular polarization suggested incoherent gyrosynchrotron radiation due to a population of electrons spiraling in the magnetic field of the ultracool dwarf@xcite. here   we have used the very large array to observe the m9 dwarf tvlm 513 - 46546 for @x Math8 hours at a frequency of 8.44 ghz on 2006 may 20 and for @Xmath8 hours from 2006 may 21 using the vla telescope at the us naval observatory, flagstaff station and the vatican observatory ( vo ), arizona. during the observation,   the radio emission from tvlms 513 was found to be broadband with net circular polarized emission reaching a periodic maximum of @x math7, properties more consistent with coherent electron cyclotron maser emission than those of the incoherentgyrosyn chrotron process previously reported by @xaite. however, the spectra of the dwarf were found to exhibit periodic bursts
we study a peculiar object detected in the field of the galaxy cluster a370.   on the _ hst_/_wfpc2_ images, it displays an unusual morphology similar to nearby ring - galaxies, although gravitationally distorted by the cluster. using mid - ir photometry and spectroscopic data obtained with the osis - v instrument ( @xcite ), we reconstruct the source reconstruction of the ring and a morphological analysis is presented. for the lensed ring galaxy,   the central bulge is clearly resolved surrounded by a @xmath124.8-diameter distorted ring which is very similar in aspect to the cartwheel galaxy. however, the outer ring is much more extended and appears less centrally concentrated than the central part. from the results of this analysis  , we conclude that the ring galaxy is likely to be a gravitational lensed galaxy.
the rapid neutron capture process ( r - process ) is one of the main processes to synthesize elements heavier than the iron group.   it is a process that occurs in the core - collapse supernovae and coalescence of binaries of double neutron star ( ns - ns ) and black hole - neutron star binary neutron star mergers ( bh - ns, e.g., *?????   * ; *???,@xcite and @xcite recently pointed out that the abundances of r -process elements in extremely metal - poor ( emp ) stars with @xmath0}\lesssim -2.5 $ ] show a very large star - to - star scatter of barium ( ba ), while the abundance of europium ( eu ) shows a decreasing trend as metallicity decreases in the met allicity range of @x Math2 } < 2.6 $ ], while it seems to reach a plateau at @x math0 } < -3.3 $ ]. based on this trend,   the model with nsm as the dominant r - Process source predicts too large abundance scatter since nsms have a very low event rate
@xmath1 properties in medium have been investigated both in experiments and in theories.   recently we developed a framework of qmd @xmath3 statistical decay model ( sdm ) for the analysis of nucleon - induced reactions in the energy region of 100 to 200 mev, and applied it systematically to the experimentally measured double - differential cross sections of ( n, xn ) type reactions from 100 mev to 3 gev incident energies in a systematic way. in this paper   we analyze the photoreactions with the same formula and the same set of parameters as the previous works of the nucleon- ( n- ) induced reactions using the qmd plus sdm approach. by comparing the results of the calculation with the experimental data and the theoretical data, we show that the calculations are able to describe the elementary collisional processes after the initial photoabsorption in a uniform way.
the ground state of a spin ladder is an aklt - like state in which short range valence bonds couple spins on neighboring rungs.   the rung singlet state is a haldane - type spin liquid phase in which there are no broken local symmetries, and the excitations are coherent magnons with a finite gap. when the two legs of the ladder are coupled not by rung couplings, but diagonally or by plaquette couplings these two phases compete with each other, and both are characterized by the absence of coherent magnon excitations and spontaneous dimerization. here   we review the properties of spin ladders in terms of the topological properties of the two phases.
we study two well - known flocking models, cucker and smale ( cs ) and motsch and tadmor ( mt ), in kinetic level.   our first result shows global existence of classical solution to the main system, as well as the long time behavior of the solution : unconditional flocking under assumption. for cs system,   the result is well - established in @xcite. for mt system, we give an alternative proof for both cs and mt systems, employing the idea of@xcite in analogy with the agent - based models.our second main result concerns with numerical implementation of system. despite being smooth for all finite time, it is found that the asymptotic behavior of solution is the formation of clusters, and in particular, flocking, under assumption ; this implies concentrations in @xmath19 as time approaches infinity.
in a recent paper @xcite, we have shown that methods familiar from continuum perturbation theory can be used to perform calculations in lattice perturbed theory analytically, except for the numerical evaluation of a small number of lattice " master"-integrals.   the goal of the present paper is to investigate if the method proposed in @xxcite remains useful for improved lattice actions which are employed in many lattice simulations. in what follows, we perform an analytic one loop calculation with the lattice qcd action used by the milc collaboration in their recent simulations with three dynamical quarks @xaqcd. as a result  , we find that the amount of computer algebra needed for perturbative calculations with such an action is significantly larger than for the simple wilson action, but they nevertheless turn out to be feasible.
the xmm - newton spectral - fit database is a database composed of spectral - fitting results for more than 120,000 unique x - ray sources, extracted from the 3xmm dr4 catalogue.   the database is composed of six spectral models : three simple models ( models 1 to 3 ), and three more complex models.database url :   http://xraygroup.astro.noa.gr/prodec/index.html+xmm-newton-spectral-fit_database.html + the database contains one row per source and observation, listing source information, and spectral - fitted output parameters and errors, as well as fluxes and additional information about the goodness of fit for every model applied.  in addition, users can construct large and representative samples of x - Ray sources by querying this database according to spectral properties.
the giroux correspondence between open book decompositions and contact structures on 3manifolds has been a key tool in contact geometry and low dimensional topology for quite some time.   the main theme explored in this note is destabilizability of open book decomppositions. here   we introduce the homologically essential arc complex and show its efficacy in studying stabilization of open books.
the issue of the structure of neutron star magnetospheres remains open.   the discovery of radiation emission from radio to gamma - rays with the pulsar period has motivated the modification of the original goldreich & julian ( gj ) model to include features, such as charge gaps, which would lead to the acceleration of particles necessary to produce the observed radiation. in this paper   we investigate the issue by means of a numerical solution of the magnetohydrodynamic ( mhd ) structure of a pulsar magnetosphere and show that the magnetic field is not only self  regulating, but also self  generating. for an unmagnetized neutron star,   both the magnetic and electric fields are strong enough to pull charged particles from the surface, and the electromagnetic cascade mechanism generates curvature photons which produce electron  positron pairs in the curved magnetic field. however, for a rotating neutron star the energy needed to generate the high energy radiation from the gamma - ray emission is much lower than the power associated with the spin down of the neutron star through the magnetic torques ; therefore, the acceleration process is more complex than previously thought.
we study the @xmath0 theory of closed bosonic string field theory.   we give the energy - momentum tensor and the action of the theory and calculate the correlation functions. in order to construct a brst invariant formulation of the worldsheet theory, we first consider the light - cone gauge string amplitudes in noncritical space - time dimensions. by shifting the number of the space -Time dimensions, we obtain a cft with the right virasoro central charge for @x Math3. using this cft, we construct a new worldsheet theoretical formulation of @x math0, which is consistent with the results of the first quantized formalism. in the second part of this paper, we show that the dimensional regularization preserves the brst symmetry of the universe.
we have compiled a list of 18 apps that offer end - to - end encryption ( e2ee ), anonymity and/or ephemerality, focusing on 8 popular ones ( confide, frankly chat, secret, snapchat, telegram, whisper, wickr, and yik yak ).   we review their functionalities and perform an empirical evaluation, based on static and dynamic analysis, aimed to compare the claims of the selected apps against results of our analysis. in this study, we find that the most popular apps do not always provide the guarantees they claim to provide : ( 1 ) users can be identified with distinct user ids that are persistent ; ( 2 ) previous activities are restored to their device after they uninstall and reinstall them ; ( 3 ) information collected by these apps could be used to de - anonymize users ; ( 4 ) the ephemeral - messaging app snapchat does not always delete messages from its servers ; ( 5 ) previous " expired " chat messages are surprisingly included in packets sent to the clients ; ( 6 ) all actions performed by a user on frankly chat can be observed from the request url, which is actually transmitted in the clear ; ( 7 ) the app telegram
a basic fact of life is competition.   idealized models of social competition have recently been proposed in which the status of each individual is determined by competitive success. in this spirit  , we introduce a simple " rate - race " model that embodies the struggle for advancement in a competitive environment. because everyone is engaged in the same perpetual rat race, one s relative standing may change slowly or not at all, even though the population as a whole may be advancing. when the competition favors the strong, the leader runs away from the rest of the population and the mean fitness undergoes periods of near stasis and explosive advancement that qualitatively mirror the phenomenon of punctuated evolution in evolution. to illustrate our model, we analyze its dynamical features for a two - agent system in 2d simulations using a deterministic version of the rat race model.
remote state preparation ( rsp ) is a general remote state preparation algorithm that allows us to prepare a quantum state with a controllable degree of mixture, and send it to a distant party.   the quantum resource is a polarization - entangled photon pair, shared by the two remote parties ( alice and bob ). in this work   we present a setup for rsp that teleports an arbitrary state encoded on the path ( or linear momentum ) degree of freedom of one of the photons of a polarization entanglement pair. using an interferometric setup that implements a controlled - not ( c - not ) gate at the path qubit @xcite, we show that the prepared state can be used to teleport a pure or mixed state from the surface of the bloch sphere volume in the trigger qubit.    we test the setup exploring several trajectories within the surface and the volume of the Bloch sphere, and we measure the average fidelity of the qt process for pure states, performing standard quantum process tomography @xmath0.
we have undertaken a study of self - gravitating magnetized tori by means of numerical simulations.   we have built an initial equilibrium structure using the self  consistent field ( scf ) method and set the angular velocity and mass of the torus to be equal to that of a central mass. in the first simulation,   a weak poloidal magnetic field is added to the equilibrium structure, with the toroidal component of the vector potential being :    where @xmath7 is the mass density. the components of the magnetic field are then scaled such that the volume averaged ratio of gas to magnetic pressure ( hereafter called the volumetric ratio ) equals 0.9 for the self - Gravitating model and 0.8 for the zero mass one. at the beginning of the simulation, a weak polar magnetic field   is added from the center of the sphere, and the equations of state are solved using time - explicit eulerian finite differencing and the constrained transport method. in both cases, the magnetic resonance energy ( mri )   grows in both models, developing approximately the same maxwell stress ( defined by @x Math12 ). in each case,    the mri is
the black hole electrodynamic model of blandford and znajek ( 1977 ) is widely accepted as the model of choice for the extraction of rotational energy from relativistic jets generated in active galactic nuclei, galactic microquasars and, presumably, during gamma ray bursts.   this model is based on the approximation of steady - state force - free degenerate electrodynamics ( ffde ), which involves the poloidal electric current driven over the surface of a rotating conductor by a non - electrostatic electromotive force. here   we review the recent results that challenge this model and show that it is not the only model of black hole magnetospheres that can be used to explain the evolution of the relativism of @xcite.
the calculation of bremsstrahlung from high - energy particles traversing a quark - gluon plasma is complicated by the landau - pomeranchuk migdal ( lpm ) effect.   the basic formalism for treating the lpm effect in qcd was worked out by baier, dokshitzer, mueller, peign and schiff ( bdmps ) and zakharov in 1996 - 1998 @xcite. here   i report on the results of a modification of this formalism that makes it more suitable for non - uniform media.
@xcite has suggested that clump - origin bulges in spiral galaxies could be different from those of the conventional ones, classical bulges or pseudobulges.   i perform a similar numerical simulation to @xcite using an isolated halo model by a @xmath0-body / sph code and study the naive natures of clumps of stars at the galactic centre, which are called clump clusters ( chain galaxies ). here  , i report the results of my simulation on the formation of a clump cluster in a high - redshift universe.
we study the ground state properties and excitation spectra of hard - core bosons, at half filling, on square and triangular lattices, with nearest neighbor repulsion.   we find that the spectra are gapless at the antiferromagnetic wavevector for the ferromagnetic xy model on the square - lattice and that as the repulsion is increased, a pronounced peak develops in the density of states ( dos ) at these wavevectors and simultaneously a sharp roton minima develops in their excitation energy. to our knowledge   this calculation has not been done before.
the agn mkn 501 is a variable source of @xmath0-ray emission from the solar system.   it has been observed with the 5 m@xmath1 air erenkov telescope ( ct1 ) at the hegra collaboration in the roque de los muchachos, la palma, islas canarias since 9th of march ( mjd 50517 ). here   we report on observations of the source using ct 1 while the results from the stereo system are reported elsewhere at this symposium and first data are already submitted for publication @xcite. compared to the system  , ct2 has a higher threshold ( 1.5 vs. 0.5 tev ) and only a 3.25@x Math6 camera of 127 pixels, but was available for longer observation time starting at larger zenith angles. also, the daq has a larger dynamic range for pulse height recording and observations can be carried out under the presence of moon light @xcide.    the data were recorded entirely in the so - called tracking mode. 	 the background was determined from previously recorded off - source data by applying modified hillas image parameters
the polarization of massive lepton pair production in proton - proton collisions is one of the most important issues in the field of quantum chemistry.   we have recently calculated the complete next - to - leading order ( nlo ) corrections to the polarized cross section and polarized parton density of the drell - yan process in @xcite which are in agreement with experimental data from the rhic ( bnl, usa ).
we investigate the question of what is the constituent profile of matter in neutron stars that is entirely composed of nonrelativistic nucleon degrees of freedom.   we use an effective chiral symmetric theory that is qcd coupled to a chiral sigma model and we find that the central density of a fast rotating 1.97 solar mass neutron star, psr j1614 - 2230, is approximately @xmath1 the central densities of a static 1.8 solar mass star. using the precision technique of shapiro delay, we show that the composition of the quark matter in the core of such a star is largely composed of colour singlet quark solitons with three valence quark bound states and the corresponding quark meson couplings are set by matching mass of the nucleon to its experimental value and the meson self coupling is set from pi - pi scattering, which in turn sets the tree level sigma particle mass to be of order 800 mev. since the centre of mass energies ( or quark chemical potentials ) of the individual quarks are not directly proportional to the density to the ( 5/3 ) power of the electron fermi energy
the exchange interactions between the magnetic states of the semiconductor and the magnetic polarons of the diluted magnetic semiconductors ( dms ) of the ii - vi type are investigated using the density functional theory ( dft ).   the supercell approach is used to investigate the exchange interactions in ( znmn)se with a very low concentration of mn and a high curie temperature. for the systems with low mn concentration   no magnetic ordering has been experimentally detected up to very low temperatures. however, the application of a magnetic field leads to the observation of the so - called giant zeeman splitting for the states of both the mn 3d and semiconductor states. because of this large spin splitting ( znemn)e is an efficient source of spin - polarized charge carriers.
we study the equilibrium configuration obtained by a modulated beam self - interacting with its own wakefield.   the modulated beams can be obtained either by pre - modulation or by the self - modulation instability at its final stage. in the first case, the beam modulates the bunch through the self-modulation instability, while in the second the beam excites the field suitable for the acceleration of the electrons via the pre - modulated structure. to obtain the more suitable equilibrium configuration we use the quasi - static approximation assuming a linear plasma response generated by a hard - cut bunch linearly interacting with a plasma with immobile ions and a two - dimensional transverse wakefield generated inside the driver.the analysis is based on the results obtained in the kenigs and jones work@xcite, in which the model used for the description of the beam - plasma interaction is traced and the possible equilibrium configurations for the bunch emerging from the model are described. during the propagation in the plasma channel the chosen equilibrium configuration evolves into the one that provides the most suitable accelerating field.
the instantaneous gluon propagator in the coulomb gauge is a central issue for studying the confinement mechanism in qcd.   the problem of scaling violation of the instantaneous propagator can be seen even at the tree level with a finite temporal lattice spacing as was discussed in ref.@xcite. here  , we take a different route to show that the instantaneous gliobasian propagator is multiplicatively renormalizable in the hamiltonian limit by using a new momentum cut and a matching analysis. on the one hand, the time - time component of the unequal - time propagation is energy independent even after the residual gauge fixing ; on the other hand, it is energy non - energy independent since the propagation is well fitted with the gribov - type form of the propagator ( or @xmath1 in momentum space ) but not with the equal - time one. from the quantum chemical theory,   it has been shown that the transverse would - be physical gluons are suppressed in the infrared region due to the proximity of the g ribov region in the zwanziger s inequality.
the binary x - ray binaries cyg x-1 and gx 339 - 4 are one of only a handful of persistent black hole candidate binaries known.   the system is a weak and persistent radio source with flux densities typically in the range 5  10 mjy at cm wavelengths and a flat ( spectral index @xmath1 where flux density@xmath2 ) spectrum. here   we report the results of several years of observations of gx339 - 4 wth the molonglo observatory synthesis telescope at 36 cm using the australia telescope compact array ( atca ) at 21.7,12.7, 6.2 and 3.5 cm wavelengths. during these observations  , we have observed a strong radio emission from the system, which is strongly correlated with both the soft ( as observed with rxte asm ) and hard (as observed with cgro batse ) x -ray flux in the x - rays low / hard state. to investigate the origin of the radio emission, we fitted the data to the most imaging pipeline and found that it arises from a compact partially self - absorbed jet, possibly of the type considered by hjellming & john
partial differential equations posed on surfaces arise in mathematical models for many natural phenomena : diffusion along grain boundaries, lipid interactions in biomembranes, and transport of surfactants on multiphase flow interfaces.   recently there has been a significant increase of interest in developing and analyzing numerical methods for solving partial differential equations ( pdes ) on surfaces numerically. in this paper   we introduce a new non - degenerate formulation of a finite element method for solving an elliptic partial differential equation on a compact hypersurface that is uniformly elliptic in a bulk domain containing the surface. to avoid surface triangulation and remeshing ( if the surface evolves ),   the method is extended from the surface to a set of positive lebesgue measures.. the results of several numerical experiments show that the proposed method is asymptotically optimal when the number of degrees of freedom used in computations decreases.
the cygnus region is the brightest diffuse @xmath0-ray emitting region in the northern sky.   it is rich in potential cosmic - ray acceleration sites, e.g., wolf - rayet stars, ob associations and supernova remnants. recently, 24 very high energy ( vhe ) @x Math 0-ray sources, including 7 pulsars, have been detected within the region with @x maths2 and @x math3 @xcite.    this region is a natural laboratory to study the origin of cosmic rays. here  , we report the first observation of complex tev emission from mgro j2019 + 37, a vhe @xMath0-rays source inside the cy gnus region, which was detected by the milagro experiment at 20 tev@xcite during the deep veritas observations of the cyg ob1 region. among the four known vhe ~20 tev @x mathematics 0-radiative sources in the region,   mgroj 2019 + 37 is the most enigmatic due to its high flux above 1 tev and its unusual two - dimensional gaussian structure.
pion production reactions induced by neutrinos are very interesting as a means to study hadronic structure.   most previous studies@xcite of pion production processes at intermediate energies considered only the delta pole ( @xmath3 ) mechanism. here   we use a su(2 ) nonlinear model with nucleon and pion degrees of freedom. for charged current ( cc ) processes our model includes all contributions depicted in the diagramas. for antineutrino induced cc processes we see our full model calculation with set ii of axial nucleon - delta form factor which gives the best results but it is still larger than the experimental data obtained at cern@xaite. for neutral current ( nc ) processes we show results for different cc and nc driven processes. in all of them   the background terms give sizeable contributions.graphical abstract
recent observations with the spectropolarimeter of the solar optical telescope ( sot ) onboard the hinode space observatory @xcite indicate that the quiet internetwork region ( the inner regions of supergranular cells of the quiet sun ) harbors a photospheric magnetic field whose mean flux density of the horizontal component considerably surpasses that of the vertical component.   we report on the analysis of existing and new three - dimensional magnetohydrodynamic computer simulations of the internetwork magnetic field aiming at following questions : does a realistic simulation of the surface layers of the sun intrinsically produce horizontal magnetic fields and can their mean flux densities indeed surpass the mean fluxdensity of the Vertical field component?   what is the polarimetric signal of this field and how does it compare to measurements with hinodes?
particle interferometry provides a tool to study the final stage of relativistic heavy ion collisions.   the hanbury - brown twiss ( hbt ) effect is used to predict the space - time evolution of the source and the radius parameters of charged pions and kaons. in this paper, we analyze the hbt data from the phenix detector at 130 gev @xcite using the bertsch - pratt parameterization for the radial size and the chaoticity of the collision centrality. by applying a full coulomb correction,   about 160 million charged pion pairs and 1 million charged kaon pairs are selected in a wide momentum range from 0.2 to 2.0 gev / c. after the pair cuts, the results are 70 times larger than those obtained in the previous runs @xcites.    the results show that the radius properties of pions are strongly dependent on the chaoticy of the collider and the collision center.  = 200 gev@xcite, the kaon radius parameters are slightly larger than Those of pionic radii at the same  . however, the ktdep values are within errors of the corresponding results at
we present a new method for network reconstruction from the transfer matrix of a linear time - invariant system @xcite.   the method is based on a polynomial - time reconstruction algorithm and uses a new model selection procedure to select the best estimate of the optimum dynamical structure function for every possible boolean network for a given number of measured states, @xmath0, then use a model selection technique to select its best estimate. in order to obtain this optimal estimate, we first remove links from the fully - connected structure of the network by judiciously removing links that are not directly linked to the full - connected state. using this approach, we obtain a set of candidate structures for each level of sparsity in the transfer matrices of the system.    this set contains one structure for every level of Sparsity and hence there is no prior bias towards sparser solutions.. the performance of the proposed method is compared with that of the most widely used method, @xaite, using extensive random simulations.
the " no - node " theory of feynman s statistical mechanics textbook states that the many - body ground state wavefunctions of bosons are positive - definite in the coordinate representation provided no external rotation is applied and interactions are short - ranged @xcite.   this statement is a very general statement, which applies to almost all the well - known ground states of boson, including the superfluid, mott - insulating, density - wave, and even super - solid ground states. however, it is also a very strong statement, since it reduces the generally speaking complex - valued many - bodies wavefun functions to be positive - definitely distributions.. we have recently made much progress with two different ways to bypass feyn man s argument, including meta - stable states ofbosons in the high orbital bands of optical lattices and multi - component bosons with spin - orbit coupling linearly dependent on momentum. here  , we review the results of these studies.
a tendency towards spin and charge ordering in cuprates has been observed in results of several neutron scattering experiments.   low frequency spin fluctuations observed by many groups at incommensurate wave vectors as relatively sharp peeks in the magnetic structure factor @xcite have been interpreted as being due to stripe fluctuations. here   we discuss the arpes spectra of doped @xmath4 ( lsco ) compounds, slightly above the doping level about @x Math5, at which, it is believed, a tendency towards nanoscale phase separation seems to be evident in the single - particle spectra obtained by means of the cluster perturbation technique ( cpt ) for the fermi energy of 15% doped@xmath7 ( nd - lsco)at the filling level about ~10 m. the evolution of the single particle spectral weight as a function of doping has been analyzed for the stripe phase using the theory of disordered charge stripes and anti - phase spin domains ; however, this theory does not provide us with much information about the underlying magnetic structure of stripes. an exact diagonalization of the model ( @x math10 m ) at a finite cluster has been performed to study stripe formation
in this paper, we address the optimization of the input covariance of bi - correlated rician channels. as the exact expression of the average mutual information is quite complicated  , we propose to evaluate its limit when the number of transmit and receive antennas converge to @xmath0 at the same rate.   we propose a simple iterative maximization algorithm, which, in some sense, can be seen as a generalization to the rician case of telatar ( @xcite ) devoted to the rayleigh context : each iteration needs to solve a system of 2 non linear equations as well as a standard waterfilling problem. for each iteration,   the eigenvalues of the optimal matrix are evaluated numerically by using numerical methods : see in particular@xcite where a barrier interior - point method has been implemented.we prove that, if convergent, then the algorithm converges toward the optimum input covariation matrix.
the nuclear many  body theory is a theoretical framework for the calculation of the properties of finite nuclear systems by having as only input the bare nucleon  nucleon interaction.   the quantities to be compared to the experiment are calculated by evaluating the mean value of the corresponding operators between the states of eq. (  ) fixed at the minimum of the energy functional. in this report   we have used the fermi hypernetted chain ( fhnc ) technology to calculate all the terms of a certain type of the operator mean value, eq.   ( [ ave ), which is obtained by performing the cluster expansion of both numerator and denominator to eliminate the so - called unlinked diagrams. with the use of these terms we have also developed a simplified model for the one  body density distribution, defined as @xcite.
we introduce a general technique for incorporating domain knowledge into dimensionality reduction for text documents.   we focus on the following type of non - euclidean geometry where the distance between document @xmath1 and document@xmath2 is defined as @x math3 here @x maths4 is a symmetric positive semidefinite matrix, and we assume that documents @x Math5 are represented as term - frequency ( tf ) column vectors. in this paper   our technique is completely unsupervised and does not require any labeled data. to evaluate the performance of the proposed methods we compare several different domain dependent geometries and show that they outperform popular state - of - the - art techniques such as principal component analysis ( pca ), locally linear embedding ( lle ), or t - distributed stochastic neighbor embedming ( t - sne ). using word - net, we also demonstrate effective ways to combine different types of domain knowledge and show how such combinations significantly outperform any of the domain knowledge types in isolation.
we present a new approach to calculate the positions and widths of three - body resonances for a model two - body interaction potential.   the method is general and can be used for weakly bound ( long range ) and deeply - bound ( short range ) resonances. as a basis set in hyper - radius  , we use the sine - dvr ( discrete variable representation ) method @xcite. at a largehyper - radius,   we place a complex absorbing potential ( cap ) to absorb the dissociating flux. positions andwidths of the efimov resonances   are obtained as real and imaginary parts of complex eigenvalues of the resulting hamiltonian of the system using the slow variable discretization ( svd ) method with adapted grid step @xmath2.1 in hyper- radius and hyperangles. by applying the method to a single resonance of three particles interacting through a potential with a barrier, we show that the obtained positions and wider widths are in agreement with the scaling law.
the effects of ferroelectric ( fe ) and antiferrodistortive ( afd ) instabilities on the phase transformation behavior of three cubic perovskite compounds, srtio@xmath0, catio@ x  =  0.1c, nanbo@x Math0, and nanbo @ x = 0.2c, are investigated using first - principles calculations.   the effect of the afd distortion on the transition temperatures, phase sequences, and order parameters for the three compounds is studied. in particular, we investigate the differences between the correlation functions of the fe and afd local modes in the structure of the two most common instabilities, namely, ferro electric ( fe)/afd ( fe+ ) and non - polar antiferroelectric(afd)/polar phonon ( pb ), as well as the interaction between the two local modes at different temperatures. to study these interactions, we construct an effective hamiltonian that describes the important degrees of freedom of the system and calculate the expansion parameters for each of them from high - accuracy _ ab - initio   lda calculations. by performing monte carlo simulations, we
the study of the multiplicity distributions ( md ) of charged particles produced in hadron - hadron collisions at high energies has received a lot of attention recently.   the data obtained by the cms, alice, and atlas collaborations at the large hadron collider at cern show that the koba - nielsen - olesen scaling of md in the full phase - space is violated up to the energy @xmath3  tev in the limited pseudorapidity intervals but it is approximately valid in the same region for the non - single - diffractive ( nsd ) collisions at the same energy. using the same concept for hadron and lepton interactions, we try to account for the structure in data which emerges in the@xmath0 interactions at high energetic levels. as a result  , we propose an alternative phenomenological approach to the description of multidimensional md in @x Math0 and @x math14 collisions.
the creation of collective atomic excitations via spontaneous raman emission plays an important role in well - known quantum information protocols, in particular the quantum repeater @xcite protocol.   a remarkable feature of such collective excitations that is of great interest for practical applications is that they can be read out very efficiently by converting them into single photons that propagate in a well - defined direction, thanks to collective interference@xcite. in this paper   we study the effects of inhomogeneous broadening of the transition between ground and excited state @xmath1 on the collective interference of the stokes photon from the off - resonant laser pulse on the @x Math4 transition.. we find that the frequency of the excited state influences the dynamics of the write pulse, and that the intensity of the broadening depends on the number of atoms in the atomic ensemble. under the right conditions   it is possible to adiabatically eliminate the excited states, but under the wrong conditions it is no longer justified to do so. as a consequence   the amplitude of the wavelet amplitudes corresponding to the different terms in the superposition of all the possible terms varies considerably, and the shape of the atomic ensembles
we propose a monte carlo method for the calculation of the electron spectrum from hard x - ray to gamma - ray continua of solar flares, produced by flare - accelerated electrons having a power - law energy distribution with @xmath9.   the model is based on the theory that the bremsstrahlung from precipitating electrons must be significantly forward - beamed, so that a majority of gamma -ray photons must be compton back - scattered by the solar materials in order to reach us. to treat this kind of physical condition which involves multiple compton scatterings,   we clearly need to use monteCarlo techniques.. the experimental data are obtained from the yohkoh hxt @xcite and rhessi@xcite experiments, and the spectra are analyzed using the fokker - planck equation and the relativistic particle dynamics equations.    the results show that the calculated electron spectrum is in good agreement with the observed spectra, and it can be used to study the energetic charged particles in solar flares.
the complete fusion ( cf ) and incomplete fusion ( icf ) processes in the fusion process with weakly bound nuclei are often divided into two categories, namely, the complete fusion and the incomplete fusion.   the knowledge of the relative contribution of the icf and the cf as a function of energy around the coulomb barrier is essential for understanding the fusion suppression phenomena at energies above the barrier. in this work,   quantum mechanical calculations of individual cf and icf cross - sections using the cdcc approach are performed for the @xmath0li+@xmath6be system @xcite on several targets at energies between 0.1 and 1.5 kcal / mol for the total fusion ( tf ) and absorption from ground state ( absorption from breakup state ) states. to understand the interaction between the breakup process and the fusion cross - section, the theoretical model based on post - form theory for the calculation of the inclusive breakup cross-sections is used.    the results obtained from the calculations are compared with the results of the coupled channel calculations at the same barrier energies. by using the combined use of the two methods, the integration of the data from the two approaches   is found to be
the weyl curvature tensor is a measure of the entropy in the space- time geometry.   it was suggested by penrose that the weyl tensor can be used as a measure to measure the inhomogeneities of the universe models. here   we survey the behaviour of this tensor in two different generic cosmological models, anisotropic bianchi type i and inhomogeneous lematre - tolman models. for both models,   the weyle curvature scalar vanishes identically in the homogeneous and isotropic friedmann - robertson - walker universe models but not in the anisotropy - induced homogeneous model. on the basis of these results  , we propose a new definition of the gravitational entropy which takes into account the effects of inhomogeneity in the universe.
the scalar part of the charge density operator is studied within the generalized coherent state model ( gcsm ).   the matrix elements of the operator are considered as function of the angular momentum projection of the intrinsic ground state and, alternatively, the projected ground state. in the case of the e0 transition operator,   both the unprojected and the projected states are characterized by different deformations but lying close to each other in energy. for the @xmath6 state, the experimental results show a large fragmentation of the two transition strengths, while the theoretical results @xcite show a very small fragmentation of only one of the transition strengths. at the same time, the calculated e2 strength for the transition from the ground state to the first@xmath10 state is concentrated in one and two states respectively, while it is much smaller for the projected state. on the other hand, for the monopole transition between the excited and ground states, the experimentally measured e0 strength is distributed in two states, while its theoretical result shows a wide fragmentation of all the states.
the 21 cm emission line of neutral hydrogen ( hi ) has been used to trace the distribution of neutral gas in the interstellar medium of disk galaxies.   the global hi line profile, contained within the beam of a single dish telescope or integrated over the entire hi distribution where resolved, provides three key indicators : ( 1 ) observed redshift of the system as a whole ; ( 2 ) the observed hi line flux, which, in the optically thin case, can be related to the hi mass ; and ( 3 ) the actual hi line full width, which when corrected to face - on viewing, is associated with the total rotational velocity of the hi gas. until recently  , the vast majority of extragalactic hi line spectral parameters were associated with observational targets selected from optical catalogs. here   we present a homogeneous compilation of the extracted hi line parameters for some 9000 optically  selected galaxies observed by us and our numerous collaborators using various telescopes over the last 20@xmath4 years. while hi parameters for most of these datasets have been presented previously, changing scientific objectives and computer capabilities have led to advances in the robustness of parameter extraction algorithms. in order to establish a well - characterized and
we study the effect of rashba intersubband coupling ( ric ) in ballistic quantum wires in the presence of in - plane magnetic fields.   we find that ric hinders the formation of subband maxima, smoothing the gap edges and, as a consequence, strongly affecting the conductance steps. this conclusion is most relevant to the strong coupling limit, when spin - orbit and confinement energy scales are of the same order of magnitude.
numerical cold dark matter ( cdm ) simulations predict a specific and universal shape for the dark matter density distributions of galaxies.   this is not what is typically observed : the mass - density distribution of, for example, dwarfs and late - type galaxies ( which do include baryons ) are best described by an almost constant density central core  ; de blok et al., 2003 ]. here   i discuss some of the concerns and criticisms of both observers and simulators, and discuss them from an observer s point of view.
the corona of the caenorhabditis elegans ( cyg  x-1 ) is a highly dynamic structure, which changes its shape continuously between waviness and approximate linearity.   we show that the shape of the corona changes during " failed state transitions " ( fst ), i.e., during times when the source reaches its intermediate state. in the soft states of 1996 and 2001/2002,   the rms - flux - relation between the lightcurve and the accretion disk is linear, but during the fst of 1999 december  05 and 2000 november 03, the linear relation breaks down. by comparing these events with the neighboring hard state observations  , we find that the observed x - ray time lag is much larger than the one observed during the normal hard state.
the liverpool telescope ( lt ) is being used to study the blast - wave physics of optically - bright prompt / afterglow emission of long bursts.   the lt s fully automated rapid response to grb triggers will enable the early - time burst afterglows, energetics, evolution and redshift distribution to be derived for a statistically - significant sample.
the global topology of the comoving spatial section of a relativistic universe is now considered in the context of the friedmann - lematre - robertson - walker ( flrw ) model.   the cosmological properties of riemannian 3-manifolds of curvature and/or topology different to that of simply - connected euclidean space are studied, and the effects of these topological properties on the dynamics of the universe are discussed.. the consequences of the global topological freedom allowed by constant curvature for the total comoving volume of an flrw model are also discussed.
the discovery of comet - like activities in four icy asteroids ( 7968 elst - pizzaro, 118401, p/2005 u1, and p/2008 r1 ) has added a new item to the mysteries of the asteroid belt.   these objects may be representatives of a new class of bodies that are dynamically asteroidal ( i.e., their tisserand parameters^{1/2}}\, \cos i$ ). while the orbits of these objects are in the outer half of the solar system, the cometary activities of these bodies may be taken to argue that they were scattered inward from the outer regions of the Solar System and were captured in their current orbits. this paper evaluates this possibility, in particular in comparison with the in - situ formation model, by presenting the results of a numerical study if the dynamics of the currently known main belt comets ( mbcs ) are similar to those of the existing ones, and discussing their implications for the formation and origin of these object.
psr j0205 + 6449 in supernova remnant ( snr ) 3c 58 is a recently discovered x - ray and radio pulsar @xcite with a period of 65 ms.   it was thought to be young due to a possible association with sn 1181@xcite, but this association has been cast into doubt by the mounting evidence that the characteristic age of the pulsar ( @xmath9 @x Math10 5400 years ) is near to its true age and hence it should share many of the characteristics of the crab nebula, including the presence of a young pulsar. here   we report on a william herschel telescope ( wht ) service time observation of psrj0205+6449 to look for evidence of an optical pulsar and its possible pulsar wind nebula ( pwn ) using the auxiliary port imaging camera ( aux ) at the 4.2-m wht at the isaac newton group of telescopes, la palma. from the results of the observations   these authors suggest that there is no evidence of a pulsar at m@xmath1322.5 @xaite, consistent with the association between
the cosmic microwave background ( cmb ) anisotropy power spectra are a powerful tool for the interpretation of degree scale cosmological models of structure formation.   they probe a large lever arm both in scale ( @xmath1 to @x Math2 ) and time (@xmath3 to @Xmath4 ), and have been shown to exhibit a degeneracy in parameter space, which can be both a hindrance and a boon for theoretical predictions. here   we discuss how this degeneracy can be used to estimate the constraints on a wide range of models using the cmb data. with the advent of semi - analytic techniques for quickly generating spectra over the entire angular range,   these constraints can be reduced to simple modifications of a standard spectrum. however, the current data provide limits on the height of the peak in the power spectrum at @x math12, which are becoming stronger, and a quick method of estimating the peak height from the data can allow one to estimate some of the constraints from degree - scale measurements quickly and efficiently over a broad range of parameter space.
high - resolution scanning tunnelling ( sts ) spectroscopy on bscco-2212 has provided some of the most provocative data on cuprate superconductors in recent years, including local information on impurity states, charge ordering, quasiparticles in the vortex state, and nanoscale inhomogeneity.   recently, sts provided intriguing results which may bear on this question, by the observation of random localized resonances at a bias of -960 mev which were argued to be states associated with interstitial oxygen atoms@xcite. from these experiments   a strong and positive correlation between the magnitude of the gap and the o dopant positions has been inferred.the success of this hypothesis raises the question of whether one can learn about the origins of pairing by studying what modulates it directly. here   we show that the modulated pair interaction is caused by the distortion of the crystal lattice around each o interstitial, which might change local electron - phonon interaction matrix elements or modulate the superexchange constant @xmath3 between nearest neighbor cu - atoms. within a strong - coupling picture   one might assume that the pair interactions are provided by the supramolecular
the factorization formalism of nonrelativistic quantum chromodynamics ( nrqcd ) @xcite provides a rigorous theoretical framework for the description of heavy - quarkonium production and decay.   the greatest triumph of this formalism was that it correctly described the cross section of inclusive charmonium hadroproduction measured in @xmath16 collisions at the fermilab tevatron@xcite, which had turned out to be more than one order of magnitude in excess of the traditional colour - singlet model ( csm ) prediction. here  , we review the h1 data from the cc dis experiment, which reveal a surprising discrepancy between the experimental and theoretical predictions for the @x Math0, @x maths13, and @x math14 mesons.. the discrepancy is likely to be resolved by the inclusion of higher - order corrections @xaite, possibly in combination with intrinsic-@xmath22 effects and/or nonperturbative shape functions.
we have degraded the images of all galaxies with redshifts 0.20 to 1.00 to the appearance that they would have had at @xmath9.   we then created a set of " postage stamp " images in which each galaxy appears as it would if that object were situated at@xmath26 in the image in which it was originally observed. for each galaxy,   the brightness and angular scale of the images were compressed by a factor @x Math20 = ( observed angular diameter ) / ( angular diameter at @Xmath9 ), using a cosmology with h@x math21 = 60 km  s@x maths22  mpc@xMath22  and @x calculations with h=6.5  cm2  s/s+1.0  km2   and h=7500  c/s/1.4  km3  , while the angular scale was compressed by an additional factor @ xmath24 ^ 2 $.  also, the intensity of the rest frame was corrected to take into account the wavelength dependence of the difference in photon detection efficiency between the wfpc2 instrument behind the f606w and f814
spinning compact binaries are promising sources of gravitational radiation for the ground based and proposed space based laser interferometric gravitational - wave detectors.   the dynamics of spinning compact binaries can be described in great detail by the post - newtonian ( pn ) approximation to general relativity. in this paper, we derive a fully 2pn accurate generalized quasi - keplerian parametrization for the conservative dynamics of spins compact binaries in inspiralling eccentric orbits using the pn accurate conservative hamiltonian which is available for the following two distinct cases : ( i ) the binary is composed of two compact objects of equal mass and two arbitrary spins, and ( ii ) the two objects have unequal masses but only one object has a spin. as the measured neutron star ( ns ) masses in ns   ns binaries usually cluster around @xmath5, case ( i).the parametric solution will be employed to construct highly efficient " ready to use " search templates for spinning compact binary pulsars moving in inspiraling eccentric orbits.graphical abstract
conjugate filter oscillation reduction ( cfor)@xcite is a novel method for the numerical solution of shock - turbulence interaction.   the cfor scheme is based on the discrete singular convolution ( dsc ) algorithm and is designed to use conjugate filters to reduce the spurious oscillations generated by high - pass filters which are implemented for the calculation of differentiation operators. in the present work,   an evaluation of the utility and limitation of the cFor scheme is carried out in dealing with the problem ofshock - high frequency entropy wave interaction, which is very challenging because conventional methods encounter the difficulty of either insufficient accuracy or excessive numerical damping. using the standard euler euler equations,.g., burgers equation, one- and two - dimensional ( 2d ) euler systems including the sod and lax problems, and the mach 3 flow past a wind tunnel with a step, the proposed scheme is found to be highly accurate and reproducible.    the most promising feature of the approach is that, the approach has controllable order of approximation for shock - capturing under practical situations.
klio is a coronographic imager to be used in the thermal infrared with ground - based adaptive optics ( ao ).   the camera will be optimized to target the thermal ir ( 3 - 5 microns ), where exoplanets are thought to peak in brightness@xcite. until now  , it has been impossible to use the thermal IR since no appropriate space - based telescope exists and the sky background is so large from the ground.. the adaptive secondary mirror at the 6.5 m mmt provides a solution to the problem of increased emissivity from conventional adaptive optics systems. by making the secondary mirror of the telescope itself the deformable surface,   approximately eight additional surfaces are eliminated compared to typical ao systems @xcite ; this results in both an emissivities and throughput that are similar to a non - ao equipped telescope. for faint objects, a conventional ao system at the mmt would need to integrate 2 - 3 times longer than the adaptive primary to achieve the same signal - to - noise in l and m bands .    klio will be a three channel system that consists of f/20, f/35, and pupil imaging
the head - on ( ho ) beam  beam tune shift for the low - energy hadron synchrotron ( lhc ) was estimated in the design report.   the nominal value of @xmath12 was defined to provide a coherent set of parameters to reach the target luminosity, but it should be considered as a conservative value and not as a real upper limit, in particular in the absence of strong long - range ( lr ) interactions. during normal operation, dedicated experiments and observations were planned to check the feasibility of colliding beams with the nominal tune shift estimated by the super proton synchoretron ( sps ), taking into account possible contributions from the lattice non - linearities and significant lr contributions. at the injection energy of 450gev,   two ` almost'nominal bunches of intensity @x maths161@xmath17@x Math18ppb and normalized emittance of 3@x math19 m were injected in each ring, with ~20 m in all interaction points ( ips ) and the collision tunes ( @xMath21, @x mathematics22 ), at an injection energy between 450 and 500gev.. the results
the search for new sources of carbon - carbon ( cp ) violation in the universe is now one of the most important subjects of particle physics.   the search for novel sources of cp violation, since its first observation in @xmath5 meson decays, has been performed in many systems, and the electric dipole moment ( edm ) of light nuclei is among the most attractive observables. to discover new sources that can be used to explain the baryon number asymmetry in our universe, the realization of experiments sensitive to them is esential. in this review   we present recent developments on the theoretical investigations of the intrinsic nucleon edm contribution to the nuclear level cp violation.
the microwave ( mw ) frequency spin dynamics in nanostructures usually involves stacks of layers combining ferromagnets ( fm ) and normal metals ( nm ) at the nanometer scale @xcite.   a time varying magnetic field with a component perpendicular to a conductive thin film induces circulating currents in the thin film plane, which produce secondary phase shifted magnetic fields in close proximity to the conductor. here  , we show that eddy - current effects can have a significant impact on the ferromagnetic resonance ( fmr ) excitation even in very thin metallic fm ( @xmath3 nm py ), determined by the sample and mw field geometry. using lithographically fabricated samples, we have systematically studied how sample and field geometry affects the coupling between the applied mw fields and eddy-current - induced fields.we provide evidence that controlling the current paths by patterned nm structures generates highly localized mwfields. this enables the excitation of spin wave modes with non - zero wave vectors (@xmath0 ), in contrast to the uniform @x math1 mode normally excited in fmr experiments.    the induced mw Field produced by the eddy currents excites damon
the infrared spectrograph ( irs ) on the _ spitzer space telescope _ operated from launch in august, 2003 to the exhaustion of onboard cryogens in may, 2009. during this period  , the irs obtained over 16,000 low - resolution spectra, most with both the short - low ( sl ) and long - high ( ll ) modules.   the cryogenic mission included hundreds of observations of standard stars, most of which were a dwarfs or k giants. using the equation @xmath3, the team at cornell chose hr  6348 as the primary standard for sl and ll because it is relatively bright, allows quick integrations to obtain high signal / noise ratios, and is close enough to the northern continuous viewing zone ( cvz ) to allow observations in nearly all irs observing campaigns. here   we describe the generation of a fully calibrated spectrum of hr 6348, to be used as the assumed spectrum when using observations of hr = 6348 to determine the spectral correction ( or rsrf ) for sl. by using a kurucz model of the a dwarf @x Math0  lac and the k giant @x math1  umi
the qcd sum rule method for the analysis of the light - quark axial - vector meson system was first proposed in @xcite, and applied to the @xmath1-meson channel.   a link between deconfinement and chiral - symmetry restoration was first established using the first three finite energy qcdsum rules ( fesr ) of the lowest dimension ( @x Math5 ) in this channel, assuming full saturation of the hadronic spectral function by the pion pole. here   we re - evaluate the results from the previous analyses using the second and third fesrs of the same dimension, together with an improved hadronic spectra of the@xmath0 resonance and the Hadronic current correlator of the //(1,2)+ quark condensate, and show that the temperature at which the squared energy threshold for the onset of perturbative qcd ( pqcd ) vanishes is about 10% below that for chiral symmetry restoration. within the accuracy of the method  , this difference is not significant, but it does provide additional information on the temperature behaviour of the @
we present a local regression method for the estimation of the reduction matrix of dimension @xmath18 in a linear regression problem.   the goal is to obtain a sufficient dimension reduction@xmath13 so that @x Math6 can be estimated without much assumption on @x math4.    we also explore three prediction methods to be used with the sufficient reduction without requiring a parametric model : ( i ) mave @xcite, ( ii ) inverse regression estimation, ( iii ) principal fitted component analysis, and ( iv ) likelihood acquired directions. by way of a locally weighted log - likelihood,   our method is able to estimate the reduction matrices of both the predictor and the reduce matrix at the same time using a single - index reduction.
the inner structure of neutron star is still unknown mainly because of the theoretical uncertainties in the extrapolation of dense matter physics to high densities.   it is believed that the baryon number density at the center of neutron stars reaches several times of normal nuclear matter saturation density ( @xmath0 ) when the hyperons or kaons enter the nuclear matter. by combining multiple observations of a neutron star at various ages, one may be able to identify the energy surface area ( eos ) which is consistent with neutron star cooling. in this work,   we use non - relativistic nuclear models to construct nucleonic degrees of freedom and employ non-relativistic hyperon potential models for the @x Math1 and @x math2 interactions. using these models, we describe the thermal evolution of neutron Stars with the nuclear electrostatic effects ( eoss ) which include both hyperons and kaons at high rates of expansion. from the results of cooling simulation, we show that the eos of neutronStars are strongly dependent on the nuclear eoss and the temperature of the neutron star.
we present a joint method for distinguishing between quasars and stars / galaxies by their photometry and for obtaining an estimate of the photometric redshift of the quasar candidates.   the method is first validated with simulations, as shown in , before being applied to real samples (   ). at low redshift, it has been shown that the usual morphologic prerequisite for _ quasi - stellar _ candidates results in a noticeable deficiency @xcite, which may be due to a bias towards blue objects.    this trend may increase the apparent evolution of Quasars. 	 the current state of the art in the optical search for quasARS is presented in  .
noncommutative field theories are nonlocal field models where the nonlocality is a well defined consequence of the noncommutativity.   it has been recently shown that the @xmath1 gross - neveu ( gn ) model is nonrenormalizable in ordinary space, but its commutative version is expandable and exhibits dynamical mass generation for both the nonlinear sigma model and the gn model. here   we show that the renormalization program for the supersymmetric@xmath0 expansion of the gn can be fully extended to the subleading order in @x Math0. the mechanism of mass generation by supersymmetry is studied with special emphasis on the role of the uv / ir mixing in the ren formalism of the supers asymmetric nonlinearsigma model.
we report on a study of the phase diagram of high temperature quantum chromodynamics with three flavors of quarks using improved gauge and quark actions  @xcite.   we find rapid crossovers, which sharpen as the quark mass is reduced, rather than a _ bona fide _ phase transition. for two cases in our study   all three quarks have the same mass @xmath6 ; and for the two lightest mass quarks the mass of the third quark is fixed at approximately that of the strange quark@xmath4.. the effects of these two cases are discussed.
in relatively close primordial binaries, the mass transfer from the primary star to the secondary is assured.   the course of the evolution of each system depends on its initial orbital period, the two stellar masses, whether the binary is part of a triple system, spin and tidal interactions, and so forth. in low - mass binaries where the masstransfer proceeds stably, regardless of whether it is or is not conservative, there is a fairly tight relation between the white dwarf mass, @xmath8, and the final orbital period for systems where the initial masses of the primaries,@xmath11, were no larger than @x math3@x Math12, and this relation is studied using a stellar evolution code that can simultaneously handle the nuclear and mass loss / gain evolution of _ both _ stars as well as the orbital evolution. with the recently developed _ kepler _ code, we find that the relationship between the orbital period and the White dwarf mass is very close to zero for systems with primaries of initial masses up to ~1.4 ( koi 74 ) and about 1.4 times larger than those of the secondary star. when the primaries of the two stars are at least one billion years old, the
we present an improved version of the stroboscopic system, previously developed and used for observing faint optical signals from pulsars, specifically the signal from the crab pulsar  @xcite.   the system consists of a chopper with out - cuts corresponding to the pulse width and with the phase of the chopper synchronized to the topocentric pulse arrival times of a given pulsar using known radio pulsar ephemerides and geographic coordinates of the observatory. in this paper   we show that the new system is able to observe the pulsar signal at optical wavelengths with high quantum efficiency and with a more detailed field of view than the current high - speed photometers ( ccds ) used for pulsar photometry.
the determination of the atmospheric parameters from the stellar spectra obtained with the gaia rvs @xcite is a common activity in astrophysics.   each comparison needs to compute a model, which can be very cpu time consuming. in order to reduce the cost,   the models are computed on a parameter grid, its sampling being as large as possible such that the parameter extraction results from an interpolation in this space. in this paper   we present a new algorithm called matisse which allows one to estimate parameters from of an optimal projection on a local environment by projection of the observed spectrum to a set of vectors computed for each parameter.
multi - quark systems are important samples for providing information on low energy quantum chromodynamics ( qcd ) interaction, especially for complex color structures.   the search for the h - particle ( 6-quark system ) has not succeeded for almost 30 years and the dibaryon state @xmath2 appeared unexpectedly @xcite, observed in double charge exchange reactions but disappeared nine years later. in 2003, the pentaquark state,@xmath6, aroused a new enthusiasm in multi - quarks because of its appearance in hadron spectroscopy. however recent high statistic experiments did not confirm the @x Math6 signal.. recently, tetra - quink states are re - interested both experimentally and theoretically because of new discoveries since 2003 @xaite.    this review will focus on the current status of these states and their role in qcd.
abstractthe gamma - ray burst ( grb ) afterglow spectra of a galaxy with a high redshift ( @xmath3 = 6.3 ) and a low metallicity ( e.g., grb060418 ) are studied using optical and x - ray spectroscopy.   we find that the absorption of the host galaxy is dominated by carbonaceous dust grains in both gas and solid phase, and that the extinction curve of the intervening system can be disentangled from that of the star - forming galaxy by measuring the total extinction along the line - of - sight to the grb as a function of wavelength. this observation is consistent with the observed lack of the 2175  feature in the extinction curves of the intergalactic intervening system, which is thought to be due to the absence of carbonaceous Dust grains in the interstellar medium. at higher redshifts,   the extinction edge of the absorbing column is shifted out of the observing window beyond which only large columns can be measured, and there is a degeneracy between redshift and x-ray column density. for high redshifting galaxies, however, the extinction edges are shifted back into the observing windows for
the goal of the project is the fabrication of a semi - digital hadronic calorimeter ( 2 bits readout ) of 1 m@xmath0 that can be used to perform measurements of high energy particle shower properties.   this prototype should be as close as possible to an interleukin-8 ( ilc)-like module, fulfilling the constraints on power consumption, geometry and electronic integration. in view of an application at an ilc detector with a 30 millions channels   dhcal, the hardroc2 chip has been developed for the detection of micromegas signals called dirac which is composed of an analog part with a current preamplifier, a fast and a slow shaper and a digital part with 3 discriminators with variable charge thresholds and a 128 event depth memory.the detector is operated in a mixture of ar/__i__c@x Math4h@x math5 95/5 and isobutane @xcite using a cathode voltage of 50v higher than the mesh voltages. due to the low ionisation potential of the quencher, high gains can be achieved at relatively low mesh voltaged voltages while maintaining a very fine transverse
the faber  jackson relation ( fjr ) and the fundamental plane ( fp ) are semi - empirical models that predict the velocity dispersions of early - type galaxies.   they are based on subhalo abundance matching ( am ), which posits a nearly one - to - one relation between stellar mass and a halo proxy, typically a mass or velocity at a chosen epoch. here   we investigate whether the properties of these models are consistent with the galaxy  halo connection implied by am. using @xmath0cdm as a framework, we find that the fjrs and fp do not exhibit a significant correlation with galaxy size, in the sense that smaller than average galaxies have larger than average velocity dispersion. however, the fp does exhibit a strong correlation with baryonic mass, with a scatter of around 0.09 dex in the model population when stellar mass is used as the independent variable. for dark matter fractions,   the results are more consistent with those obtained from hydrodynamical simulations, but only in the most extreme cases.
the next generation particle physics facility may be a neutrino factory ( @xcite ) or a muon collider ( @xmath16 ).   each of these facilities has been proposed to advance in - depth study of fundamental questions in particle physics. with the latter,   the decay of stored muons produces a well - understood, fully characterized, intense and narrow beam of muon neutrinos that can be used to study the neutrini sector, the golden oscillation channel, leptonic cp violation, and the mass hierarchy of the higgs boson. for the former, it would provide the best chance of discovering cp violation in the lepton sector. because muons are much more massive than electrons, they have negligible synchrotron radiation, thus making possible a high - energy circular lepton collider with a very small footprint. with such advantages over traditional@xmath14 colliders, consideration must be given to the possibility of creating amuon collidion with guidance regarding energy scale to come from large hadron collider results.
the mott   @xcite and the anderson  @xcite routes to localization have long been recognized as two of the basic processes that can drive the metal - insulator transition.   theories separately describing each of these mechanisms were discussed long ago. however, for systems in which both the correlations and the disorder effects are strong, complementary methods are required. in the present paper, we focus on extensions of the dynamical mean field theory ( dmft ) to describe the effects of disorder and correlation on the behavior of two - dimensional semiconductor structures in which the correlations are so strong that the system is in the strongly localized ( atomic limit ) limit. here   we review the principal physical ideas on the interplay of correlations and disorder, as already presented in the early works of mott,  @excite, and then discuss how this physical behavior is naturally described by the extended dm ft approaches.. the results show that the most important consequences of disorder are the formation of a metallic phase in the absence of electron - electron interaction, and the existence of a local magnetic moment at each site, which is due to the transmutation of conduction electrons into local magnetic moments.
in r - parity violating models the single resonant production of charged sleptons in hadron - hadron collisions is possible.   the dominant standard model backgrounds to this process come from gauge boson pair production, production of zz or wz followed by leptonic decays of the gauge bosons with some of the leptons not being detected. here   we study the background to like - sign dilepton production at the lhc @xcite and the tevatron@xcite using monte carlo simulations and the mssm signatures of the detector. for each of these experiments we impose cuts on the transverse momentum and isolation of the Like - sign lepters.    we find that the background from gaugeboson pair formation is reduced by a factor of 2.5 ( ~1.5% ) when the transversal momentum is reduced to < 0.5 kcal / mol.,1 for the isolated hadron as a lepton, the background can be reduced by an order of magnitude by applying the following cuts : ( i ) a cut on the interconversion energy of the like - signs so that they are less than @xmath17 about the direction
the origin of the @xmath0 nuclides, which are usually considered to be the result of neutron - capture processes, is still a matter of debate.   we present a monte carlo method to quantify the contribution of nuclear uncertainties to the production uncertainties of selected nucleosynthesis models. in order to obtain a quantification of final abundance uncertainties,   the model uncertainties are introduced in each simulation step but the initial uncertainties are due to the astrophysical reaction rates used in the nuclear reaction networks. using this method, we show that the uncertainties in the abundances of several nucleosynthetic processes can be quantified in a self - consistent and automatic manner by varying the rate at which the process is studied. here, we focus on the@xmath10 process in massive stars, which depends on the assumed initial abundances based on the observed solar system amounts of the proton - rich isotopes @x Math2 +, @x maths3 +, and @x math4 +.    we find that the results of the current study are consistent with the predicted abundances for all of the models, except for the one where the initial abundance is lower than the expected value because the model
a prototype for an open classification system for stars with spectral types a to k and scaled solar metal abundances is presented.   the parameters derived from spectroscopy are connected to a widely accepted scale of effective temperatures based on the infrared flux method, and the performance of the method is checked.. the proposed system is tested by comparing the results with those of several other methods that have been developed in the past decade.
the two - mode squeezed state is the paradigm of the epr state for light modes.   this state can be used to demonstrate that quantum mechanics is nonlocal by using the polarization states of the two modes of light. in this paper  , we derive the wigner function for a two -mode squeezed state which has internal noise. here   we analyze the dynamics of nonlocality and study the many features of this quantum state, such as separability and the behavior in the steady state. from these features,   the effects of noise on the nonlocal features of the state are studied.. the steady - state solution for the state with internal noise is found to be an exact, non - gaussian solution of the gaussian wienner function for the continuous variable werner state and a phase - diffused state. under the conditions for pure separation and separability of the mixed entangled state, the results show that the state is nonseparable. however, under the presence of quantum noise, the state exhibits some degree of nonseparability and shows a strong dependence on the strength of the nonlinearity of the crystal interaction.
in the early universe during the quark - hadron phase transition ( qht ) the universe passed through the temperature range which included the critical t = t@xmath3 for the qcd chiral phase transition from the quarks - gluon plasma ( qgp ) to the hadronic phase ( hp ).   we assume that this phase transition is first order, in which case bubbles of the hp could form, nucleate and collide until the our hp universe emerges with t at about 100 mev at 10@x Math2s. using an instanton - inspired model of qcd, we study the possible formation of bubble collisions during the qht using ( 1 + 1)-dimensional collisions in minkowski space and find promising gluonic structure arising in the interior of thehp bubble.
the bending - induced sliding of multilayer graphene layers under peeling - induced bending is known to influence the stacking and registry of the stack.   however, the detailed mechanical behavior of sliding stacks and the registry changes under bending have been poorly studied. here   we perform molecular dynamics simulations to show that peeling-induced bending generates complex sliding patterns that alter the local stacking and registries of multi - layer multilayered graphene systems. in particular, we show that the folding of the stacked layers is affected by the rotation of the armchair ( ac ) stackings from zigzag to armchair or from abc1 to abc2, while the stacking of the unpeeled layers is not affected by any of the other stackings. when the peeled layers are rotated around the z - axis, it turns out that the sliding of the layers is influenced by the rotational direction of the arginine atoms on the peeled stack. as a result,   the folded layers tend to slide with respect to each other rather than compress, which is explained by the interlayer shear modulus of the bent stack. at the same time, the rearrangement of the Stack Registry also affects the
we propose a method for the measurement of the ratio of the particle momenta moving in opposite directions, @xmath8, using two beam momentum monitors at opposite sides of a 180@xmath0 bending magnet.   the measurements are sensitive to the directional variation of the speed of light as formulated in the mansouri - sexl test theory and could be interpreted in terms of the standard model extension, whose odd - parity parameter @xcite.
the southern sky has been very attractive for proper motion hunters in recent years, because of the low completeness of the luyten catalog of stars with @xmath3 yr@xmath1 proper motions at low galactic latitudes.   recently, improved data - mining techniques have been used to conduct a massive proper motion survey of the northern sky, using data from the digitized sky survey ( dss ). in a systematic analysis of dss scans with the superblink software, an automated blink comparator,   several hundred new @x Math3yr@x math1 stars have been discovered in the north sky, effectively filling up the low galactic latitude gap @xcite, and also significantly increasing the complementation of the proper motion census at high galactic latitude @xcitite. in this paper, i report the discovery of a first set of 182 new stars with #xmath17 yr@Xmath1 good proper motions in the southern sky, found after completing the analysis of @x maths18 of the sky south of @ xm19 ( 8980 sq.deg. ) by combining the results of the previous analysis of the southern declinations of the dss with those of the whole northern
the main goal of learning to rank is to learn automatically ranking functions using a machine learning algorithm, in order to optimize the ranking of documents or web pages.   several algorithms have been proposed during the past decade that can combine a very large amount of features to learn ranking functions. whereas the number of features that can be used by algorithms have increased,   the issue of feature selection in learning to Rank has emerged, for two main reasons. as more and more features are incorporated into algorithms, not only the models become more difficult to understand, but also they potentially have to deal with more and less noisy or irrelevant features. in this paper, we consider an embedded approach for feature selection at the level of the learning algorithm @xcite@xcite.we propose a general framework for feature selectors inlearning to rank using support vector machines ( svm ) and a regularization term to induce sparsity. here  , we first propose an accelerated forward backward splitting algorithm to solve the @xmath0-regularized problem. then, we propose a reweighted @x math0 algorithm to handle the non - convex penalties that benefits from the first algorithm.    we conduct intensive experiments on the letor 3.
the nature of the ground state of doped quantum antiferromagnets is a central issue for the theory of correlated electrons.   while it is well established that arbitrary small doping destroys conventional nel order, it is far less clear what is the structure of the emerging ground state, and how it co - exists with superconductivity. in our previous work   we have shown that the spiral state of the extended @xmath0 model, @xcite, is stable ( at low doping ) above certain critical values of@xmath2.. in addition we have found that superconductive properties are supported in the stable region. in the present work we extend our calculations up to two loops for both the charge and the magnetic response. using chiral perturbation theory as our main technical tool, we find that the magnetic stability is due to spin quantum fluctuations ( order from disorder effect ) in two loops, however the higher corrections are found to have an important effect on the charge stability region in the space of parameters @x Math2, generally increasing stability.
we jointly optimize source precoder matrix and relay forwarding matrix for mutual information maximization under channel estimation errors.   the optimal structure of robust transceivers is derived based on the properties of matrix - monotone functions, and an iterative water - filling solution is proposed. in order to guarantee the transmitted data at the destination, it is assumed that the channels between the source and the relay are greater than or equal to @xmath12,@xmath31, @x Math14, and @x math15.    the results show that the proposed robust transceiver design is more efficient than the existing linear transceiver designs for multi - input multi - output ( mimo ) relay systems.
the high precision measurement of the calorimetric electron capture ( ec ) spectrum of the isotope @xmath0ho is extremely interesting as it can be used to study the feasibility of future experiments investigating the electron neutrino mass @xcite.   the experiment discussed here has been achieved by implanting @x Math0ho ions into a thin surface layer of a planar particle absorber made of gold which afterwards is covered by a second gold layer. in the following we compare the results obtained with a detector having an ion - implanted absorber with results obtained using a detector taken from the same fabrication run prior to the implantation.
we analyze the passive stability of a class of elastic bodies moving in a perfect fluid.   our primary motivation is to examine the role of body elasticity as a mechanism for passively stabilizing the coast motion of fish. here  , we model the fish as an articulated body formed of rigid links with torsional springs at the joints ( with stiffness @xmath4 ). using a family of relative equilibrium solutions, we find that the sea motion of the elastic body is passive when the deformable body is subject to initial conditions only and is passively responding to the surrounding fluid.see research article http://www.biomedcentral.com/1471-2148/10/9/8.
we present a new method for the determination of the main phenomenological parameters of algol - type variable stars ( e.g., brightness at maxima and minima, period, initial epoch, duration of eclipse in per cent, or asymmetry ).   the method is based on the use of complete equations for the least squares ( lsq ) approximation of the extrema of the spectroscopic light curves of the eclipsing binary systems. using the lsq approximation,   these parameters are determined for the first time for the ukraineian set of known algols, which are characterized by relatively narrow eclipses, which can be observed in the phase light curve of eclipsing binaries, especially of the algobol type. to obtain the best possible agreement between the obtained results and the observed light curves, we have used the same approach for the calculation of the amplitude of the secondary minimum and the duration of the total eclipse as for the calculations of the luminescent variables. with the exception of the magnitude of the second minimum, which is usually computed using the fourier coefficients, all the other parameters are approximated using the algebraic polynomials of the user - defined
the fulde - ferrell - larkin - ovchinnikov ( fflo ) phase of the attractive hubbard model has recently attracted a great deal of interest from both the experimental and the theoretical community.   the most favorable systems for the observation of the fflo phase were predicted to be clean superconducting films in the presence of an in - plane magnetic field, above the so - called clogston - chandrasekhar limit. however, despite the fact that the original prediction dates back to more than thirty years ago, the f floating phase has been very elusive to detect. here  , we investigate the pairing correlations in the spin - polarized ground state of the attractively trapped 1d Hubbard model in the absence and presence of a zeeman field using density - matrix renormalization - group calculations. by combining the exact solution of the gaudin - yang model with a local - density approximation, we find that the pairwise paring correlations between the charge and spin degrees of freedom of the two fermi species are decoupled at low energies for small polarization, which is consistent with the assumption that they are strongly anisotropic. as a result,
the optical monitoring camera, omc @xcite, observes the optical emission from the prime targets of the gamma - ray instruments on board the esa mission integral.   it has an aperture of 50 mm focused onto a large format ccd ( @xmath1  pixels ) working in frame transfer mode (@xmath2  pixels imaging area ). for this purpose, an omc input catalogue @xcites has been compiled and contains most gamma and x - ray sources, variable stars, and hipparcos and tycho reference stars for astrometric and photometric calibration. to make the data available to the scientific community, we have developed a scientific archive, containing the data generated by the omc and an access system capable of performing complex searches, complementary to the integral archive hosted at isdc.laeff.inta.es/omc.
we investigate the low - temperature properties of the spin-1 antiferromagnetic heisenberg chain with bond - alternation ( s1ba ) at the gapless point for  using the conformal field theory.   we find that the behavior of the uniform susceptibility is close to what is expected from the affleck - haldane conjecture, and that the quantum monte carlo simulation results are in good agreement with the numerical results obtained by numerical calculations. on the other hand,   the staggered susceptibility is observed experimentally at very low temperatures, and the high - temperature property of the compound is not explained by the field - theoretical prediction.
zero - shot learning ( zsl ) is an active research topic in machine learning, computer vision, and natural language processing.   many practical applications can be formulated as a zsl task : drug discovery, bilingual lexicon extraction, and image labeling, to name a few. in each of these tasks,   the classifier is given a set of known example - class label pairs ( training set ), with the goal to predict the unknown labels of new examples ( test set ). in this paper, we propose using ridge regression to map labels into a label space, where nearest neighbor search is carried out to find the label closest to the mapped example, and this label is then output as the prediction for the example. after mapping the examples into the label space from the training set, we show that the emergence of " hub " labels, which are simultaneously the nearest neighbors of many mapped examples, has a non - negligible effect on the prediction accuracy of the test set.
we present results of simulations of a fractional - order system with the aim to investigate the stability of such system.   the control systems used so far were all considered as integer - order systems, regardless of the reality. because of the higher complexity and the absence of adequate mathematical tools, fractions of real objects were only treated marginally in the theory and practice of control systems. for many of them the fractionality is very low. however, for some of them it is very high. from purely experimental methods   we made at first an analysis of the fractional dimension of the controlled systems and properties of fractional regulators. on the basis of these results,   two exact methods for the synthesis of fractionals - order controllers were derived. since the development of the methods described in works @xcite required the elaboration of methods of fraction algorism analysis in the frequency domain, the following bode analysis was utilized for the formulation of the method for the controller synthesis and such regulated control systems stability analysis.
solar neutrino deficit has been strongly established in all the first generation solar neutrinos experiments @xcite and in the already started second generation experiments @xmath4.   the observed solar neut rino flux is considerably lesser than the standard solar model ( ssm ) predictions@xcite, which leads one to assume that the resonant spin - flavour precession ( rsfp ) of solar neutrinos is solely responsible for the neutrinino deficit. in the present work   it is found that the quality of data fit is very sensitive to the magnetic field profiles used @xaite. by analysing the solar neutRino data within the framework of rsf p scenario   a particular shape of the magnetic profile can be obtained from the scenario, as a reflection of solar neut Rsfp data.
the most studied and well understood electromagnetic properties of neutrinos are the neutrino magnetic moments ( nmm ), along with electric dipole moments.   these properties are of particular interest, because they open a door to " new physics " beyond the standard model ( sm ). in the present article   we discuss the search for non - zero nmm in the laboratory experiments on low - energy elastic neutrinuclear - electron scattering ( les ) experiments on dirac and majorana @xcite neutrines. among the experimental results,   the obtained values are at least two orders of magnitude smaller than the current best upper limit of the theoretical nmm value, and there is also a huge gap between these values and the prediction of the minimal extension of the sm.
we study the linear dynamics of surface waves and internal perturbations in deep fluid in the absence of wind and presence of the fluid flow with vertical shear of velocity.   dispersive characteristics of shear modified surface gravity waves ( sgws ) as well as linear mechanism of surface wave generation in deep fluids are studied in detail in the framework of the non - modal approach. to reduce the mathematical complications as much as possible but still keep the basic physics of our analysis  , we consider fluid to be incompressible ( which drops sound waves ) and neglect the stratification effects. after these simplifications we maintain just two modes of perturbation - sgw and vortex mode and write up the following differential equations for thelinear dynamics of perturbs of velocity and normalized pressure :    @xmath5   from the boundary condition on the surface @x Math0 : @x math11   ; )-( to temporal one. then, after the fourier transform with respect to@xmath13 and @x maths14, we study the temporal evolution of spatial spatial fourier harmonics ( sfhs ) of both modes of
the faraday rotation of pulsars and extragalactic radio sources is the best probe of the galactic magnetic field on the large scale.   the rotation measure ( rm ) of a source is proportional to the integration along its line of sight of the product of the radial magnetic field and electron density, @xmath3. here   we review the history of the use of pulsar rms to study the structure of the magnetic field in the galactic halo and disk with a principle similar to the ct technology used for medical imaging such as scanning electron microscopy ( sem ) or computed tomography ( ct ). since the first observations of the antisymmetric rm distribution of extradial radio sources as well as pulsars, covering all the inner galaxy, reflects the azimuthal field with reversed directions above and below the galactic plane, entirely consistent with the field configuration of an a0 dynamo, whose origin probably lies in a dynamo in the halo. from the results of these observations,   it can be concluded that the local uniform field is directed toward about@xmath9. the most important factor in the determination of the direction of the field is the distance from the sun
henize 2 - 10 is a dwarf elliptical galaxy with a starburst nucleus and the first wolf - rayet galaxy identified.   gas motions in and around it suggest that it is in an advanced stage of accretion, which may be the trigger for the starburst @xcite. to better match the resolution of the radio observations, we have obtained high resolution ( @xmath20.3 ) middle - infrared ( 11.7 micron ) images of the central disk in he 2 - 101 using the long wavelength spectrometer ( lws ; *   * ) on the keck telescope. at 1.1 " resolution  , these images show two main ir sources possibly associated with 4 of the 5 images ; deconvolution reveals a possible third, weaker source to the east of the main emission.
cosmic strings are linear gravitational stable topological defects which may have been created as a consequence of phase transitions in the early universe and are predicted in the context of the standard gauge field theory of elementary particle physics with extra symmetries.   the geometry of the spacetime associated with an idealized cosmic string, i.e., infinitely long and straight, is locally flat but topologically conical, having a planar angle deficit given by @xmath4 on the two - surface orthogonal to the string and a magnetic flux running through its core. here  , the authors have investigated the effects generated by the conical structure of the cosmos string spacetime on the vacuum fluctuations associated with scalar and fermionic fields in terms of the vacuum expectation value ( vev ) of physical observables like the energy - momentum tensor and the induced fermion current density in the cosmological model of the cosmic string. for the first time, the effect of the magnetic flux on the vev of the charged field in the presence of a single - walled carbon nanotube has been investigated in the space of a static static cosmic string where the ratio of the quantum one to the classical one
the present paper is a review of the research on regular and chaotic motions in elliptical galaxies that i have done over the last few years.   it is intended to provide a brief overview of the current status of the field and to discuss some of the issues that have been of particular interest to me and which i have strived to clarify with my research : 1 ) can we build stable triaxial models of stellar systems that contain high fractions of chaotic orbits? ; 2 ) is the distinction between partially and fully chaotic orbits of any use? ; 3 ) is figure rotation significant in triaxia stellar systems? ; 4 ) which are the usefulness and limitations of frequency analysis for the classification of large numbers of regular orbits in model stellar systems?
wetting phenomena occur very often in daily life and has a strong interdisciplinary character.   it is of great relevance for fundamental areas of knowledge such as physics, chemistry, biology, and several other applied sciences. in this paper   we apply a well established methodology using md simulations to study interfacial properties and surface phenomena in a model binary lj fluid mixture in which the attractive part of the a - a interactions is weaker than the a- and b - b interactions. by studying the properties of the density profiles of the fluid phases as a function of temperature and miscibility parameter  , we show clear evidence that the vapor phase spontaneously excludes the liquid a - liquid b interface at and above the wetting transition temperature.the results of the extensive md simulations are presented and discussed.
the higgs boson is a spin-0 particle that forms the most mysterious field within the standard model ( sm ) of elementary particle physics.   the structure of the radiative corrections to its mass is quite different from those of fermions and gauge bosons, and is related to the scale at which the loop integrals are cut off. under a proper regularisation scheme  , we can remove these corrections by cancelling out the chiral symmetry of the fermion and gauge symmetries, and replacing them with a new symmetry which exchanges fermias for bosons. in this review   we will discuss some of the current approaches to this fine - tuning problem, including supersymmetry and quantum gravity.
we investigate the onset of oscillatory rayleigh - bnard convection in a low - prandtl - number fluid rotating uniformly about a vertical axis  @xcite under stress - free and no - slip boundary conditions.   the results show that the instability onset is always unsteady at the onset for the dimensionless rotation rates below a critical value @xmath19, and the convection is always unstable at the stability onset for all rotation rates above this value. however, the oscillatory convection may appear at small or moderate rotation rates for low- and high - pranert - number fluids when the velocity and temperature fields are in the range of 1.5 to 2.0  kj / cm2 and the taylor number is less than 0.1, respectively. as the rotation rate increases, the entropy of the convective flow increases, and so does the probability of the formation of instabilities and bifurcations on the surface of the fluid. with increasing rotation rate, the stochasticity of the liquid decreases, and it is found to be more pronounced for the higher rotation rates. also, the equilibrium between the steady state solution and the instability begins to change at the
extragalactic jets are thought to play an important role in providing a heating mechanism in the center of cool core ( cc ) clusters of galaxies.   recent observations of the double twin - jet system, 3c 75, located in ngc 1128 at thecenter of the nearby galaxy cluster abell 400, suggest that there are two colliding jets with a mean diameter of about 2.5 cm and a mean velocity of ~1.2 km / s.    we show superimposed radio and optical images of the collision of the two jets using a combination of hydrodynamical and magneto - hydrodynamic simulations and compare the results with those of x - ray observations. for the first time  , we show that the observed star formation rate is much lower than predicted, and the cooling times in the dense core of some cc clusters are much shorter than the hubble time. however, the collisions of the jets are extremely energetic events, thus they offer a unique opportunity to study astrophysical plasma under extreme conditions and infer the physical properties of jets based on the comparison of hydrophobic and magnetic field simulations with observations.
the heterogeneity @xmath0 is a quantity associated with how heterogeneously sized the equilibrium domains are, which was recently proposed in the context of explosive percolation   @xcite and then applied to ordinary percolated systems.   it only takes into account whether a given size is present in each configuration and gives the number of such distinct sizes. here   we re - evaluate the original formulation for the equilibrium scaling behavior of @x math0 for the ising model and present new results for both geometric and physical clusters  . while the former considers all nearest neighbor parallel spins belonging to the same domain, the latter only takes the fraction of spins effectively correlated. for the geometric domains,   no peak has been observed for the system sizes considered in ref. at high temperatures, thermal noise breaks large clusters and the fragments are small, and so is the diversity and @x Math0. on the other hand, for sufficiently large systems, the presence of a very large, perhaps percolating, cluster leaves small room to the other clusters, also decreasing the diversity.
compact steep - spectrum sources ( csss ) and gigahertz - peaked spectrum ( gps ) sources with a turnover in their spectrum at frequencies in the ghz range are seen through the solar wind.   inter - planetary scintillation ( ips ) observations of a large sample of css and gps radio sources at 327 mhz using the ooty radio telescope ( ort ) have been made to determine the sizes and prominence of hotspots to investigate the collimation of radio jets and the evolution of these sources, as well as the existence of radio halos at a low frequency on the scale of hundreds of milliarcsec in addition to the more compact structure suggestive of earlier periods of activity. from the ips observations, we have determined that the size of the hotspots is dependent on the prominence of the dominant component from the power spectrum, and the relative prominence of these hotspots depends on the source luminosity and linear size. by comparing the spectra of five gps sources with those of several css sources,   we have also determined the shape of the main component from both ips and interferometric observations, and discuss possible reasons for their spectral shape.
the antares neutrino telescope is located in the mediterranean sea close to the southern french coast of the city of toulon.   it detects the cherenkov light emitted by ultra relativistic neutrini - induced muons along their path and reconstructs the direction of the primary neutrinos from the collected data. using a likelihood fit that uses a detailed parametrization of the probability density function for the photon arrival times, the expected event flux from the fermi bubbles ( fbs ) is several order of magnitude lower than the atmospheric neutrine flux, that represents an irreducible background.the main idea of this method is to compare the measurement done in the fbs area ( on zone ) with a background estimated from data itself looking into an area outside the fbbs ( off zone ). according to a proposed hadronic mechanism for gamma ray emission @xcite, the fgs can be a source of high - energy neutrines.    the results of this analysis are compared with the results obtained from the montecarlo ( mc ) experiment at the same location.
microarray data analysis is one of the most important research topics in applied statistics.   the major challenge in microarray - based class prediction is the problem of high - dimensionality, where the number of genes or variables ( @xmath0 ) far exceeds the number and complexity of samples or observations (@xmath1 ). to overcome this problem, we propose a latent variable approach for handling high - dimensional microarray data and show its promising potential for class prediction. using a set of latent variables that describe features that are not directly observable but do have a measurable impact on observable variables, we find that it is possible to induce a class predictor ( classifier ) using available learning samples ( i.e., gene expression profiles ) from different diagnostic classes. given the learning samples representing different classes, first the classifier is learned and then the classifiers are used to predict the class membership ( i,e.susceptibility ) of unseen samples. here  , we demonstrate the application of this approach to class prediction by comparing the performance of two class prediction methods, namely, logistic regression and discriminant analysis, using microarray gene expression data.
stochastic differential equations ( sdes ) play an important role in the quantum theory of decoherence and measurement as well as in computational many - body physics.   however, efficient numerical techniques for solving such equations have not yet been developed. here   we develop variable stepsize ( i.e. adaptive ) explicit runge - kutta based integrators for sdes using taylor expansions of strong solutions of ordinary differential equations. by comparing the results of the taylor expansion of the solutions of sdes with those of the exact solutions of the n - body schrdinger or liouville - von neumann equations, we demonstrate the use of the method by solving a variety of stochastic wave equations arising in decohesion problems and in stochastically decomposition of the many -Body problem.
we present a method to calculate the conductance through a ring in which both the kondo physics and the interference effects are present.   the method is based on the ionic hubbard model, which is used to describe the quantum wells of the rashba spin - orbit coupling that is present in nanoscale systems like quantum wells. using the continuum version of the model, we show that the conductivity of the ring oscillates not only as a function of the applied magnetic field ( aharonov - bohm effect ) but also under the action of both, magnetic and electric fields together with rashba Spin - Orbit coupling ( @xmath7 ). by applying the formalism to the ring, we have been able to find the form of the Hubbard model in the presence of the quantum dots, which adequately describes the periodicity with the applied electric field seen in the experiments.
the net baryon number is  @xcite@xmath5 in the standard model ( sm ).   this ratio is expected to be on the order of @xmath6 in the near future. for non - degenerate systems like for example elementary particles, including hadrons, an electric dipole moment ( edm ) is only possible if the two fundamental symmetries, parity and time reversal invariance, are violated. a step - wise approach to determine charged hadron edms with a sensitivity of ~13 cm   is presented. after investigations of systematic errors at the existing cosy ring an upgraded cosy storage ring will be used to perform a first direct measurement of a chargedHadron edm. following this   the next step will be the construction of dedicated storage rings at forschungszentrum jlich in germany ( all - in - one - ring for proton, deuteron and light nuclei ) and brookhaven national laboratory in the usa to reach for a higher sensitivity of~15 cm.
the recent discovery of the planet proxima  b orbiting in the nominal  habitable zone " of our nearest stellar neighbor @xcite presents a unique opportunity to further study the properties and the evolutionary path of exoplanets.   we have applied a state - of - the - art magnetohydrodynamic ( mhd ) stellar wind and magnetosphere model to estimate the space weather conditions experienced at the orbit of proxima b. the model assumes that the coronal heating and wind acceleration are due to alfvn wave turbulence ( and thus they depend on the magnetic field strength ), and it takes into account radiative cooling and electron heat conduction. using the zeeman - doppler imaging ( zdi ) map of gj  51, an active m dwarf of similar spectral type ( m5.5 ) to proxima, we find that the magnitude of the star's surface magnetic field is proportional to the size of the solar corona, and that the poynting flux from the corona is much larger than expected from the observed scaling between the magnetic flux and the activity level of @xmath4600  g / cm2 proxima@xcite. by taking into account the observed
the extinction of stellar light as a function of wavelength is a powerful way of studying interstellar dust properties, and in principle to discriminate among different dust production sources.   accurate measurements of interstellar extinction curves ( isecs ) are almost exclusively limited to our galaxy because at greater distances it becomes impossible to obtain the photometry or spectroscopy of individual stars needed for extinction determinations. here   we use the long - duration gamma - ray burst ( grb ) afterglow to study the extinction properties of interstellar dust in high redshift galaxies using the so - called drude approach, which uses a parametrized functional form for the normalized ( to the visible ) extinction, the drude model. by taking into account the experimental data from the @xcite study, we show that the observed extinction profiles of grb host galaxies are not consistent with the theoretical models, but rather are based on a synthetic description of dust that is well - grounded in the physical properties of the observed cosmic dust.. the proposed model fits the data well enough to be valid for the milky way galaxy ( mwg ), and can be used to infer the extinction profile of the grb hosts.
we present a comprehensive account of the hydrodynamics of a wave energy converter ( wec ) based on relative motion of two cylindrical bodies, which are allowed to move in heave, as well as sway and roll.   this entails an investigation of different wec sizes and damping coefficients and their performance in wind - generated sea surface waves given by a pierson - moskowitz ( pm ) spectrum. for the heaving truncated cylinder,   the results show that the captured power of the wec increases with the larger the cylinder size and the damping coefficient, and that the maximum captured power is obtained when the device is able to absorb energy from waves independent of direction. for all three modes of motion, the wecs perform equally well, with the exception of the self - reacting devices, which exhibit significantly lower captured power than the other two types of wecs. using the pm spectral description of the sea surface, we derive values for the  significant displacements  of the oscillating bodies, and thus add a measure of survivability to the design considerations.. finally, an illustrative grading system can be devised to categorize the various performance metrics of theself - reacting we
walter harrison s theory of the electronic structure of solids @xcite has been very sucessful in providing a physical understanding of the electron structure and the characteristics of bonding.   however, harrison's theory of solid state has limited ability to produce accurate numerical results for the band structure, density of states and the relative stability of different crystal structures. in this work  , we have developed a procedure that while maintaining the simplicity of h Harrison s approach gives an impressive improvement that puts the theory on a quantitative basis. by fitting the augmented plane wave ( apw ) energy bands of the transition metals v, cr, ni, cu, nb, mo, nc, pd, ag, ta, w, pt and au to the apw energy bands used by harrison, we obtained new hopping prefactors for each of the 12 transition metals and fitted them to the corresponding apw energies of the rest of the periodic table. using these new hoppingPrefactors, we obtain new onsite terms for the energy bands and fit them to first - principles predictions of the total energies and predictions of relative stability. as a result,   our hamiltonian corresponds to an orthogn
the rotation period, derived from the periodic photometric modulation induced by surface spots, is a key parameter in stellar evolution and is directly linked to many fundamental astrophysical processes, including magnetic field generation, stellar winds, star - disk interaction, and binary formation.   the rotation period of brown dwarfs ( bds ) is one of the rare stellar parameters that can be measured with high precision ( @xmath0% ) for large samples. here   we present first period measurements for bds obtained with kepler s k2 mission @xcite. using the latest version of pyke@xcite, we show that the k2 lightcurves cover the entire period range for young bds at ages of 5 - 10 myr, and provide a new census of the rotational evolution of bds.
metastable states are generally viewed as equilibrium states, i.e.  as having a well - defined free energy, which is however distinct from that of the corresponding equilibrium state.   nevertheless, it is also clear that such states eventually decay through a process of nucleation which brings the metastable state to a true equilibrium state which is physically quite different. in this respect, there have been many attempts to justify associating some equilibrium state to metastability through analytic continuation of the free energy. for models with short - range interactions,   however, matters are more complicated : it has been shown that the free energies of the equilibrium ensemble have an essential singularity at the coexistence curve. here   we show that this singularity is due to the presence of droplets which eventually nucleate the equilibrium phase. by taking a purely dynamical point of view  , we suggest a reasonable definition of metastability in terms of dynamic features alone and show that it can indeed be viewed as the restriction of the canonical equilibrium ensemble onto a suitably defined subset of all configurations. to achieve this goal, however, we must assume that the system obeys very simplified dynamics, namely markov chains satisfying detailed balance.
the recoil - induced resonances ( rir ) and the collective atomic recoil laser ( carl ) are two of the most popular topics in nonlinear spectroscopy.   they relate to probe field absorption or gain in the presence of a pump field, and are generally regarded as arising from raman transitions between different center - of - mass states. here  , we compare the rir and carl and demonstrate that the two processes are equivalent in terms of the formalisms used to describe them.
the mode coupling theory mct is the only one which provides a microscopic description of simple liquid glassformers.   it predicts a critical temperature @xmath0 for the onset of slow dynamics where non - exponential relaxation and non - arrhenius behavior emerge. in this work, we investigate the role of rotational degrees of freedom ( tdof and odof ) in the freezing process of two partially disordered systems : the so - called orientational glasses such as cyanoadamantane and cyclooctanol which are rotational analogs of canonical liquid glass formers and exhibit a partially dis ordered phase, called plastic, which possesses a crystalline translational order and a dynamical orientational disorder. using molecular dynamics simulations, we show that the thermodynamic behaviour of the rotational motions of the two systems can be described by a combination of experimental and theoretical results.. the most important feature of the model is the presence of a non - arhenius motion of the system at the calorimetric temperature@xmath2 which is not observed in the case of the orientationational glasses. to test the hypothesis that the mechanism of the transition from the orientational phase to the plastic phase is due to
the angular power spectrum of galaxies can be used to quantify the density of cosmological matter, dark matter, and dark energy in the universe.   we present new measurements of galaxy angular power spectra from the sdss dr7 using a volume - limited sample created by @xcite, and compare these measurements to a theoretical three dimensional ( 3d ) power spectrum by using the photometric redshift distribution of the galaxy sample. with these comparisons, we can extract constraints on any parameters that effect the power spectrum, including bias, cosmology matter density, @xmath11, baryon density,@xmath12, or neutrino masses. for the first time, we use the code for anisotropies in the microwave background, also known as camb, to fit our estimated angular powerspectra to theoretical, nonlinear 3d matter power spectroscopically measured angular power Spectroscopic data, and examine the effects this has on the @x math5 fits to extract Cosmological parameters such as bias, density, and/or dark matter density. here  , we describe the experimental design, implementation, and results of our experiments.
we study theoretically nanoelectromechanical effects in doubly - clamped suspended single- and multi - wall carbon nanotubes.   we demonstrate that a gate manipulates the tube in an effective way, and show that the applied gate voltage bends the tube, changes the stress and thus influences the electric and mechanical properties of the nanotube. by considering the influence of initial stress and thermal fluctuations, we show that coulomb blockade effects dominate transport for a single - wall ( swnt ) carbon nantube in which the junction capacitances are zero.    we also show that intrinsic bistability occurs when the tube is strained.
the stepwise 3-photon ionization of muonium in a non  monochromatic laser field with a time   dependent amplitude is studied.   the effect of the time - dependent frequency variation ( chirp ) of the laser field on the energy separation of the @xmath1 transition in muonial atoms is investigated using two counter  propagating pulsed laser beams with almost identical intensities and the same photon energies. as expected, the chirped laser signal immediately makes its appearance in appreciable spurious shifting and broadening of spectral / photoionization lines, due to the rapid refraction index variation of the _ laser media _ and is hardly avoidable, especially with powerful pulsed lasers, unless some technical developments are made in order to compensate the frequency alteration observed in the case of the experiment in hydrogenic atom @xcite.
quantification of the health effects of air pollution is an important statistical modelling problem that is of considerable public interest, and public health agencies and government departments are required to estimate both its financial and health impact.   recent increases in the availability of small - area statistics have allowed these effects to be estimated using an ecological small - areas design, where the study region of interest is partitioned into a set of non - overlapping areal units, and the number of disease cases arising from the population living in each areal unit is modelled, using poisson regression, with a number of risk factors including average air pollution concentrations, measures of socio - economic deprivation and demography. for each case,   a random effect is introduced into the model by means of a spatially correlated random effect for eachAreal unit, and these random effects are assigned a conditional autoregressive ( car, @xcite ) prior as part of a hierarchical bayesian model, which typically assumes a single global level of spatial smoothness determined by geographical adjacency, and is not flexible enough to capture the complex localised structure likely to be present in the residual spatial correlation. here   we develop a new _ localised conditional autoresgressive
a kinetic theory of forced granular gases is required to model a variety of industrial processes where energy is added to the grains to enhance mixing and transport.   we have used a single layer of identical spherical particles to study the steady state statistical properties of a granular gas, which is a collection of inelastically colliding particles that are separated by a thin layer of aluminum rim. using high speed imaging technology, we have directly measured particle velocity distributions and density correlation functions that are non - maxwellian, and the cross - correlation between density and temperature fluctuations for the fluidized state and the fluidization transition in a simple representation of the granular material @xmath0granular.we have found a complex phase diagram that bears many similarities to equilibrium two - dimensional systems, but we have also direct measured particle velocities that show non - equilibrium effects @xcite, and our results are reported in .
we reanalyze the photoproduction processes at the hera, including single - inclusive charged hadron, prompt photon, and drell - yan dimuon production, in order to determine their sensitivity to the spin - dependent parton distributions of longitudinally polarized beams.   we find that the most sensitive processes are jet and prompt photon production, with the latter finding an improved sensitivity to @xmath2_ and _@xmath9. for the other processes,   the highest sensitivity is found for dijet production, which is the only process that provides a clean separation of the ` resolved'part of the cross section.
the study of transport and mixing in coastal flows is of major interest because of their economic and ecological importance.   the bay of palma, spain, is a semi - enclosed basin located in the southwest of the island of mallorca ( western mediterranean sea ), whose coastal flow is mainly induced by the wind. in this work   we investigate the surface horizontal transport during two months corresponding to different seasons ( autumn and summer ), and therefore to different wind conditions, in order to highlight the effect of the wind on transport. using lagrangian techniques developed from dynamical systems theory, we compute the barriers and avenues to transport ( lcs ) from lines of high values of finite - size lyapunov exponents ( fsle ) obtained from velocity data of a realistic numerical model at high resolution, which resolves spatial scales of a few hundred of meters. based on the definition of lcs given in section , we find that the main barriers are identified in the domain of distance between the bay and the open ocean, and the main avenues are found in the area of the bay with more or less connectivity with the open sea.    we also present calculations of residence times
we investigate the detectability of gravitational waves ( gws ) emitted from a binary system consisting of a stellar mass object and an intermediate - mass black hole ( imbh ) harbored in a dark matter ( dm ) mini - spike.   we find that the gw waveform can be extracted with very good accuracy by gravitational wave ( gw ) observations if the central imbh has a high density dm region around the central bh, which is called a dm spike. to test our results, we also investigate how the detection accuracy of the dm parameters changes depending on the masses of the binary components and the density profile of the Dm mini-spike.
the ground - state energy for a many - electron system can be expressed as a functional of the two - electron reduced - density - matrix ( @xmath5-rdm ) @xcite and thus the energy may be determined without knowledge of the many electron wave function. in this paper  , we derive cepa - like overlap equations for the parametric @x math5-rcdm method to elucidate the connection between the two methods.   the overlap equations are derived from the topological matrix of the coupled electron pair approximation ( cepA ) via a diagonal shift to the hamiltonian matrix@xcite.    the results show that the overlap equation is more closely related to the cephalograms of the cepas than to those of the other parametric methods.
electronic transport in mesoscopic systems has been at the focus of experimental and theoretical interest during the last decade due to recent development in fabrication of small electronic devices and their interesting equilibrium and non - equilibrium properties.   especially interesting are the transport properties of a quantum dot ( qd ) under the influence of external time - dependent fields. in this paper   we investigate the electron transport through a qd with a bridge channel between a source and a drain driven out of equilibrium by means of a dc voltage bias and additional time - independent external fields. using the evolution operator technique  , we give the analytical expressions for the qd charge and current assuming so called the wide - band limit approximation and the time- and frequency - independent strength of the Qd - lead barriers. additionally, we present the model and formalism and give the resulting expressions for equations for the corresponding matrix elements of the evolution operators.
angular momentum transport is a fundamental process in the process of accretion through accretion discs.   it is the detailed process of angular momentum dispersal that determines the structure of the accretion disc and therefore the rate at which gas, supplied from the mass donor, is actually accreted by the compact object. despite being predicted in the 80s,   observational evidence for spirals was first found in 1997 in the accrete disc of the eclipsing dwarf nova ip pegasi, and since then such waves have been confirmed in several outburst events of ip peg as well as in other cataclysmic variables. here  , we review the current status of the observational support for the existence of density waves in the disk.
the optical light curves of classical novae show a wide variety of timescales and shapes.   various empirical time - scaling laws have been proposed in the attempt to recognize common patterns and to unify the nova light curves. recently, @xcite reported that the visual and infrared light curve of several novae follow a universal decline law, and interpreted that in terms of free - free emission ; in particular, the time - normalized light curves were found to be most strongly correlated with the time of maximum flux in the 1455   continuum.
helium is the second most abundant element in normal stars and has a pronounced effect on their structure and evolution.   unfortunately, helium abundance can not be determined spectroscopically for low - mass stars because of their low temperatures. as a result,   the initial helium abundance of stellar models depends on an assumption about galactic chemical evolution. when additional data are available, the helium abundance is often treated as one of the free parameters that are adjusted to obtain the best fit to the data ( e.g., *???   * ; *????* ; *???', *??,1 ). here  , we show that this approach can be used to determine the helium abundances of other stars using the signature that helium ionization leaves on the sound - speed profile of a star.
the wang - landau sampling ( wls ) method is a well established monte carlo algorithm.   it is applicable to almost all stochastic simulations, and has been used in studies of polymers @xcite and proteins@xcite. however, limitations in the energy space cause some distortions in the estimation of the density of states. recently a way of circumventing this problem, using adaptive windows  in wls  , was developed that allows one to simulate larger systems by dividing the parameter space into slightly overlapping subintervals, so called windows, and simulating each separately. as a result the probability distribution and the thermodynamic properties do not suffer from the distortions that arise using conventional wls with fixed windows. in this paper   we describe the adaptive windows ( aw ) algorithm and present results of aw simulations including the _ entire _ range of energies for chains up to 300 monomers on the square lattice.
compton gamma imagers are needed to assist investigators in intelligence gathering prior to or after a radiological or nuclear incident.   we are designing a compact instrument capable of localizing a 10  mci point source of cs-137 40  m away to within a few degrees, in a field of view of @xmath2 in both directions, in under a minute. using the beamnrc / egsnrc monte carlo simulation packages, we have constructed models of compton gamma imagers using four different scintillator materials, labr@xmath0, nai, caf@x Math1 and caf@Xmath1, and polyvinyltoluene - based plastic scintilator, hereinafter referred to as pvt. for each material, we looked at the probability for an incoming gamma to compton scatter or to undergo a photo - electric process, as a function of material thickness.the results of this study show that the optimal thickness of the scatter detector is determined by the amount of depth within the slab of material, and the number of layers of scatter detector layers depends upon the size of the source of radiation. with the help of the monte
the renormalization of coulomb gauge yang - mills theory within the lagrange formalism is still unsolved.   we provide general connections between the greens functions in the two formulations that should help to perform the renormalisation in the lagrangian framework according to the insight obtained in the hamilton framework. at vanishing sources associated to the momentum fields the effective action ( _ i.e. _ the generating functional of one - particle - irreducible ( 1pi ) green s functions ) of the ham Miltonian approach reduces to the one of the lag rangean approach. this allows to reduce the set of dyson - schwinger equations ( dses ) in the first order formalism to the corresponding set derived from the standard path integral representation. for a corresponding generating functional the integration over the momentum field   can be performed and any @xmath1point function involving this field as the average of a polylocal function of the quantum canonical momentum fields can be determined, which means that the full correlation functions involving these canonical variables can be found as a functional of those that usually appear in the standard paths integral representations. in this paper   our results explicitly verify, in agreement with other approaches, that there
a new method to construct solutions of a system of ordinary differential equations in terms of the laurent series is presented.   this method is based on the painlev test, which allows to determine the dominant behavior of the initial system solutions in the neighbourhood of their singular points and then transform them into linear algebraic equations on coefficients of the first order polynomial differential equations.    the results show that the use of the Laurent series solutions gives additional algebraic problems for the generalized hnon   heiles system, for which analytic and laurentseries solutions have been found in @xcite.. the main properties of this method are discussed.
quantum feedback networks have emerged as a natural class of objects with which to address assemblies of quantum input - output components so as to allow feedforward and feedback connections.   this offers a convenient framework to formulate problems in coherent quantum control and robust quantum control problems @xcite-@xcite. here   we study the effect of coherent feedback on the squeezing of the input noise field by a degenerate parametric amplifier ( dpa ) for a single quantum input field coupled to a single cavity mode acting as an idealized squeezing device, and we consider a set up involving a simple beam splitter to introduce the feedback loop. using coherent feedback, we find that the maximum squeezing is obtained when the internal degrees of freedom are eliminated from the system.    we show that the dependence of the degree of squeezing on the reflectivity of the beam spliter is due to the effective damping of the source mode and the effective coupling strength of the excitation mode.
quantum weak energy inequalities ( qweis ) are state - independent lower bounds on the expectation value of the smeared energy density of a quantum field.   they hold for any globally - hyperbolic spacetime, and are optimal for all states in the fock space of the minkowski vacuum for which contributions from high momenta or high particle number are damped ( e.g. exponentially ). here  , we review the history of the study of qwei for the dirac field in two - dimensional flat spacetime and explore the generalisation of this work to interactal field theories.
the transition to turbulence in parallel flows is notoriously difficult, specifically we notice that most textbooks treat this subject via linear stability which actually does not help much to understand phenomena which are non linear including at the onset.   nevertheless some understanding of the observed transition can be derived from an in depth analysis of the weakly nonlinear analysis ( amplitude equations ) in the pertinent regime. in this approach   the space dependent behavior can be understood thanks to a " generic " extension of the original landau s model for amplitude equations to include a slow space dependence for linearly unstable waves.the main result of our analysis is that noise may be or may not be present in the flow structures that develop spontaneously inside the localized turbulent spots.
the ntt deep field ( nttdf ) study of faint galaxies in an ultra - deep multicolour susi field was conducted at the eso ntt in february through april 1997 in service mode with seeing better than 1 arcsec.   the field is 80 arcsec south of the @xmath0 qso br1202 - 072 and is partially overlapping with the field centered on the qso and studied in the same 4 optical bands and in four color bands : red, blue, uv and visible. to obtain limiting magnitudes in the four bands which would enable photometric redshift estimates to@xmath20 or about 1.5 magnitude fainter than in the previous work by giallongo et al. for the first time  , we have used ground - based observations with the susi ccd camera at the Eso new technology telescope to measure photometrical redshifts for @x math18 galaxies down to a limiting magnitude of @x Math19. from these results,   we show that the population of galaxies at this limit is much larger than previously reported and that the distribution of gravitational shearing is more complex than previously thought.
in the present work, we investigate the analytical behavior of a lower dimensional holographic superconductors in the probe limit of the string theory using the variational method.   it is shown that the phase transition of the quantum theory along with the scalar field can be solved analytically by matching the asymptotic solutions of fields near the ads horizon to the horizon solutions at an arbitrary ( completely arbitrary ) mid point, and then we find the expectation value of dual operator @xmath4 and the critical temperature@xmath5 analythetically.. the results show that the optimal conditions for the optimization of the critical temperatures are found to be the following : the time scales of the phase transitions are close to the center of the black hole ; the energy of the phases is small enough to satisfy the boundary conditions ; the polarization of the system is not affected by the field s backreaction effects on the gravity sector ; the intensity of the interactions between the two quantum operators is high enough to cover the entire system ; the density of the systems is low enough to fit the experimental data ; and the surface area of the singularities is large enough to allow the measurement of the size of the particles in the black holes
the origin of fermion masses and mixing apart from @xmath0 violation remains one of the least understood aspects of the standard model ( sm ) of fundamental particle interactions.   experiments performed during the last two decades have established that neutrinos have small but nonvanishing masses which leads to a further increase in the number of free parameters in the yukawa sector. here  , we investigate the phenomenological implications of parallel hybrid texture structures of both the charged lepton and the neutrino mass matrices in a nondiagonal basis under the assumption of non - factorizable phases in the neutrinoless mass matrix. for the charge lepton,   all the twelve classes of hybrid textures can be grouped into twelve classes such that all the hybrid textures belonging to a particular class have the same physical implications. using an effective theory with the sm gauge symmetry and some discrete non - abelian family symmetries, we find that the most important effect of the flavor asymmetry is the presence of a texture zero in the lepton mass matrix and the existence of an equality in the mass matrix elements between the neutral and non - neutral elements. on the other hand, the effects of the quaternion
the semileptonic @xmath7 transition of the light cone ( lhc ) heavy baryon is analyzed in the framework of the qcd sum rules.   the main ingredients in analysis of this channel are form factors entering the transition matrix elements. using the most general form of the interpolating field for the@xmath1 heavy beryon as well as the distribution amplitudes ( da s ) of thelight @x Maths0 baryons, we first calculate all twelve form factors in full theory. then, we use these form factors to calculate the total decay rate and branching ratio of the considered decay channel. in the next section,   we obtain qcdsum rules for the form factors. in sections 3 and 4, we numerically analyze the form factor and use them to estimate the related decay rates and branching fractions. in this section, we focus on the calculation of theform factors corresponding to the @x math7 semileptic decay which proceeds via @x maths8 transition at quark level.
a new quantum mechanical method of energy extraction from black holes is proposed.   this method is based on a gedanken experiment on quantum energy teleportation ( qet ), which has been recently proposed in quantum information theory @xcite@xcite. by measuring the local fluctuation induced by a zero - point oscillation in the ground state of a many - body quantum system and by announcing the measurement result to distant points, energy can be effectively teleported without breaking any physical laws including causality and local energy conservation. in this paper, we consider this qet protocol for @xmath0 massless fields in the near - horizon regions of large - mass black holes with near - horizons geometry described by the minkowski metric. using this protocol,   the hartle  hawking state of the field in the black hole spacetime, which is the thermal equilibrium state with the hawking temperature, is reduced to the minkingowski vacuum state in flat spacetime. during the local operation, surplus energy of the local fluctuations   is emitted to the external systems and can be harnessed. as a result, the amount of energy extracted by qet does not exhibit thermal property like hawking radiation
the estimation of quantum parameters is an important task in quantum metrology and parameter estimation.   the optimal estimation of a general one - parameter channel has been studied and some optimal estimation schemes have been proposed. however, these schemes mainly consist of the identification of an optimal input state and an optimal estimator of the output state. in this paper, we present a new approach to find the optimal input states and the corresponding accuracy limits for the optimization of the quantum fisher information ( qfi ) for unitary quantum processes. by taking advantage of the convexity of the qfi  , we show that maximal entangled states can be obtained for a many - body system where the quantum process is a trace - preserving completely positive map, which is also called a quantum channel. using the inverse of fisher information, we find that the precision of the estimation is bounded from below by the lower bound of the error limit.
the absolute carrier - envelope phase ( cep ) of the few - cycle laser pulses is a very important parameter for determining the strength of the strong - field - matter interaction.   however, the time - delay of the generated soliton pulse can not be determined in the presence of light amplification due to the violation of the inversion symmetry of light - matter interactions in two - level systems. in this paper, we introduce the counter - rotating terms ( crt ) in the spontaneous emission damping, and investigate the influence of crt on the propagation dynamics of nonamplified single -cycle laser pulses in two-level media. by using the resonant resonant extreme nonlinear optics effects as a reference point, we present a simple approach for measuring the cep of the many - cycle ultrashort laser pulses with moderate intensities without light amplification. when the incident single - cycle pulse with envelope area @xmath2 propagates throngh the two - stage medium, it splits into two pulses, which show a pronounced cep dependence : the stronger main pulse moves faster than the weaker generated solitation pulse, and the pulse time - delayed between them shows a pronounced effect of the cephalogram.
the semiclassical quantisation of a three - dimensional spherical harmonic oscillator ( ho ) hamiltonian using properties of its periodic orbits is investigated for a spherical system.   it is shown that the solution of the trace formula g_sc(e ) = _ n ( e - e_n = g(e)+g(e),  in the extended gutzwiller trace formula can be obtained from the einstein - brillouin - keller quantisation for the unperturbed system, where the anharmonic term is the strength of the perturbation which first is assumed to be small, but later may assume arbitrary positive values. as a result  , the total amplitude of the oscillating part of the quantum - mechanical density of states is given exactly in terms of a quantum spectrum and separated into two terms by g(dgsc ) = dgsc / s_po(e)/s_po/2, where g(i ) is the sum of all periodic orbits of the classical system, g(ii ) is their action integrals, and g(iii ) is one of the stabilities and degeneracies of the periodic orbits.
the theory of radiation transfer is of paramount importance for astrophysics.   the equation of radiative transfer is very likely to be present in all astrophysics courses, more likely at the master level. despite the often very crude approximations used in these cases, such solutions may still be very useful to any astronomer willing to " clutch at straws" while facing a problem of interpretation of data ( or of numerical results ) involving some more or less complicated radiative modelling. here   we review the analytical solutions to the non  local thermodynamic equilibrium ( lte ) radiation transfer problem which can be derived and used for the first time in the context of the radiation transfer theory.
the kosterlitz - thouless ( kt ) universality class is a well known one in fermionic theory.   it is generally accepted that the critical behavior near a finite temperature phase transition in a model consisting of fermions can be described by this class. however, until now no one has been able to check the universality arguments with precision beyond the kt universality starting from a microscopic fermion model. in this letter   we present the first results from a meron - cluster algorithm which confirms the existence of a kt Universality class in a large @xmath6 fermi model. using the concept of a merons  , we have solved the sign problem and found that there is no critical slowing down in the calculation of the critical behaviour near a three dimensional ising transition in the form of a quantum spin model at a temperature of ~1.5 k. the results are consistent with the predictions of the renormalization group analysis @xcite.
the top quark is the heaviest fermion in the standard model ( sm ) and its mass is at the electroweak symmetry - breaking scale.   because of its large mass, it is expected to be more sensitive to new physics than other particles. in this work   we analyze vector and scalar unparticle effects on top quarks spin correlations in pair production process @xmath15. since the top quink is very heavy its weak decay time is much shorter than the typical time for the strong interaction to affect its spin@xcite, top polarization information is not distributed by hadronization effects and transferred to the decay products.we find that the top - antitop quark spin correlations can be used to search new physics beyond the sm.
the explosion of a chandrasekhar mass white dwarf as a type ia supernova is one of the most dramatic events that can befall a star.   the outcome depends on details of the ignition process and the uncertain physics of turbulent flame propagation. in this paper   we consider a comparatively simple question : " is presupernova carbon burning inherently unstable - even in the absence of urca losses?"we pick up the white dwarf when it has just ignited carbon and is developing an extended convective core and perform a linear stability analysis of the structure of its evolutionary models prior to explosion, based on a similar analysis performed for very massive stars. following ignition, a convective region develops in the white Dwarf that eventually grows to encompass most of its mass. during this phase  , the star ignites carbon centuries before it finally explodes, commencing a long ramp up that eventually concludes when convection can no longer carry away the excess energy generated by the degenerate nuclear runaway. at the end of the ramp up, the central temperature decreases to @xmath6k and the star dies about 300 years until the star s death.the results of our analysis show that the evolution of the interior of the white
coherent radiation by large collections of small particles has been studied extensively with applications in antennas, atmospheric scattering or plasma diagnostics.   the behavior of those macroscopic scattering devices is ruled by the interference of the fields scattered by many microscopic elements. in atomic physics,   matter - light interactions can be studied extensively in the past decades, ranging from spectroscopy to laser manipulation of the atomic internal and external degrees of freedom. as atoms appear to be excellent systems to study any possible deviation from classical many body features, it is a general interest to understand and to control cooperative effects, even at a classical level, in a cloud of atoms. in this paper  , we consider the phenomenon of radiation pressure in a regime where scattering is dominated by cooperative effects. for a cold atomic cloud with a gaussian density distribution irradiated by a plane wave laser beam, which is sufficiently detuned from resonance so that the average number of excited atoms in the cloud is less than unity, we assume that only one among @xmath0 two - level atoms is excited by absorption of a single laser photon, which then spontaneously emitted into vacuum modes with frequencies @x Math1 and @xMath2.. we show that the spontaneous
shock acceleration is widely believed to be the mechanism for the prompt emission of gamma - ray bursts ( grbs ).   this paper explores the general expectations for burst emission spectra from shock acceleration theory, and the relationship between the electron energy and angular distributions obtained by a synchrotron shock emission model and those obtained by acceleration simulations. in particular, the effects of particle acceleration on the thermal and non - thermal distributions of the electron population are discussed.    it is found that acceptable fits are only possible with a marked dominance of non - Thermal electrons, contrasting the particle distributions obtained in acceleration simulations.the results of this analysis are interpreted in the context of known results from acceleration simulations using the bright burst grb 910503 as a representative case study.
the objective of this investigation is to study three - dimensional ( 3d ) flows of viscous incompressible fluids which are constructed to exhibit extreme growth of enstrophy.   it is motivated by the question whether the solutions to the 3d navier - stokes system on unbounded or periodic domains corresponding to smooth initial data may develop a singularity in finite time. here   we analyze the time evolution induced by the extreme vortex states first identified by @xcite and compare it to the time evolvements corresponding to a number of other candidate initial conditions considered in the literature, including the euler euler equations and the " active scalar " equations. using a fundamentally different approach to the use of available computational resources, we demonstrate that the taylor - green vortex, studied in the context of the blow - up problem by@xcite, is in fact a particular member of the family of extreme vortex state maximizing the instantaneous rate of enstophy production in the limit of vanishing enstrokephy. based on these findings, we identify the set of initial data for which one can a priori guarantee global - in - time existence of smooth solutions.
spinor field is a well - known particle that plays a principal role in almost all stable elementary particles such as proton, electron and neutrino.   however, in cosmology, the role of spinor field was generally considered to be restricted. only recently, after some remarkable works by different authors, showing the important role that spinor fields play on the evolution of the universe, the situation began to change. this change of attitude is directly related to some fundamental questions of modern cosmology : ( i ) problem of initial singularity ; ( ii )problem of isotropization and ( iii ) late time acceleration of the cosmos.
abstractthe aharonov - bohm ( ab ) effect, which engenders so - called _ persistent current _, has been explored for various types of mesoscopic rings, based on metals and semiconductors, using magnetic and transport experiments.   although magneto - conductance characteristics have garnered considerable attention, optical manifestation of the ab effect has remained a controversial subject. in this paper, we report self - production of nanometer - sized gaas quantum rings on ( al, ga)as by means of a droplet epitaxial technique @xcite. because of their good cyclic symmetry, together with high tunability of the ring size and shape,   the present system is expected to open a new route to implement the ab effects within the optical regime.. both the ground - state transition and the excited - state phase transition are identified by single quantum ring photoluminescence ( pl ) spectroscopy. from the theoretical results, it is found that the ab signature can be explained by a composite nature of excitons, in which both an electron and a hole are excited simultaneously ; the net charge inside a ring decreases to zero, and the loop current associated with a magnetic flux
the molecular ism is a highly turbulent structure.   there is evidence that this turbulence can support the clouds against gravitational collapse and thereby control star formation. in this letter   we test the hypothesis using high resolution numerical simulations with the newly developed code ivine ( *???   * hereafter g08 ). to mimic initial turbulence we employ a supersonic turbulent velocity field ( mach 10 ) with a steep power - law @xmath6, where only the largest modes@xmath7 are populated initially. under the influence of isothermal hydrodynamics simulated with the tree / sph - code vine ( @xcite, @xaite )   the initial turbulence is reduced to a sub - millimetre - sized region of the cloud at a temperature of ~2k and a mean number density of ~3.5 j / cm2. as the turbulence decays rather quickly, the only way to explain this high level of turbulence would be to drive the turbulence - either on large scales by i.e. supernova explosions or on small scales from within the cloud by stellar outflows, winds or ionization. for the first time we show that the effect of ionizing radiation on the
the heterotic string model @xcite has a 6d orbifold grand unified model ( gut ) limit, where two compact dimensions are much larger than the other four, with 6d bulk gauge group @xmath3 and unbroken@xmath4 symmetry at two fixed points. in this paper   we analyse the vacua of the 6d orbitifold gut using expectation values of all 6d zero modes.   several vacua with semi - realistic yukawa couplings can be identified where to order six in powers of standard model singlets @x math1-term and gravitino mass both vanish.. the decoupling of exotics and the generation of superpotential terms are studied in the context of the vacuum studied in @xaicite.
evolutionary path predictability depends on the fraction of the trajectories on fitness landscapes that are accessible for evolutionary exploration.   we show that model - derived and experimental landscapes of protein evolution are significantly smoother than random landscapes and resemble moderately perturbed additive landscapes ; thus, these landscapes are substantially robust to mutation. in contrast, the model landscapes show a deficit of suboptimal peaks even compared with noisy additive landscapes with similar overall roughness. because direct experimental investigation of fitness landscapes is technically challenging, the available studies only explore a minuscule portion of the landscape for individual enzymes. here  , we propose that the smoothness and substantial deficit of peaks in fitness landscapes could be fundamental consequences of the physics of protein folding.
the metallicity of globular clusters in the sombrero galaxy m104 has been studied using multi - object spectroscopy.   the results show that the metal - rich clusters in m104 are more likely to be older than those in the milky way, and have a higher abundance of iron - peak elements than the non - solar globulars. for most of the clusters,   their metallicities are positively correlated with their radial velocities, and the relative abundances of these elements are highly correlated with the mass of the cluster.. the presence of iron in the halo of m104 is associated with a strong correlation with the radial velocity of the galaxy, which is in agreement with the observed radial velocity systematics.
high energy ion generation in the interaction of intense laser pulses with mass - limited targets is promising for applications in a wide range, from the development of ion sources for medicine and the fast ignition of controlled thermonuclear fusion to the investigation of warm dense matter, high energy density phenomena, and laboratory astrophysics.   we carry out two - dimensional ( 2d ) particle - in - cell ( pic ) simulations using the remp code based on the density decomposition scheme @xcite to investigate the effects of magnetic squeezing and electric field intensification at the target edge on the ion acceleration in the presence of a plasma corona around a mass - restricted target. under these conditions,   the coulomb explosion of the ion core of the target is enhanced due to the density squeezing by the quasistatic magnetic field, formation of a density hole near the tip of thetarget due to plasma resonance, etc. in the case of an optimised preplasma, the intensity of the laser pulse interacts first with the target surface, where it forms a long - living quasi - static magnetic dipole leading to the magnetic vortex acceleration regime, or can create a shock wave putting into effect the shock wave acceleration. while the main
we derive the double logarithmic ( dl ) asymptotics of scattering amplitudes for a sequence of gauge theories leading up to the standard electroweak model.   we start with the processes where all the scalar products @xmath4 of the momenta of participating particles are of the same order, and then compute the dl corrections to processes governed by massless non - abelian gauge theories. in the interesting case of broken gauge symmetries, we turn to the effects of dl effects for standard model electroweak processes.
the magnetic chemically peculiar ( mcp ) star @xmath0  cvn ( hd  112413, hr  4915 ) displays strong line profile variations in the visual spectral region, attributable to the non - uniform chemical abundance distribution on stellar surface, particularly of the lines of fe, cr and ti.   the spectra of 22 swp, 10 lwr and 6 lwp have been obtained with a resolution of about 6    from the buss ( balloon - borne ultraviolet spectrograph ) using the large aperture ( 9.5@xmath4  @x Math5  22@x math4 ).    the fluxes at the cores of the large features and spectral lines are investigated by fitting the observations to the linearized least - squares method. for each star,   two sets of spectra were obtained : the rebinned spectra from the high - dispersion images of @xMath0 cvn and the low - resolution echelle spectra obtained with the refractive index ( ri ) spectrographic system. based on the fit of the ri spectra, the photometric line index ( pfi )   is proposed
the spin - dependence of interfacial phase shifts ( sdips ) can modify the behavior of mesoscopic circuits.   recently, a single wall carbon nanotube ( swnt ) connected to two ferromagnetic leads with collinear polarizations has been shown to be an interactionless wire subject to the sdips@xcite. however, the effect of interactions on the transport properties of a central region connected to ferrom magnetic contacts has not been studied. in this article  , we study the effects of thesdips on the conductance peaks of a quantum dot coupled to metallic leads through spin - active interfaces. using an anderson model, we find that the @xmath0 of the circuit above the kondo temperature is affected by the interaction effects. for the first time, we show that the effect depends on the occupation of the dot in the interacting case. when the dot is occupied by an electron with spin parallel or antiparallel to the magnetization of the ferromagnet, the dipole energy levels are significantly reduced, while for the dot with spin perpendicular to its magnetization, the peak energy levels increase. at the same time, the transition state of the resonant states is unchanged.
we study the inflation model driven by the linear potential derived from the axion monodromy inflation model, taking a correction term for non - perturbative effects into account.   we find that the sinusoidal correction term increases the predicted @xmath7 to as much as 0.1 - 0.15 for the number of e - folds @x Math12 50 - 60, which corresponds to the cosmological scale@xmath13. in the case where the tension between bicep2 and planck is resolved by a large negative running, the size of the inflationary observables is not enough.
we report on a new set of lieb - thirring - type inequalities for intermediate and fractional statistics, which follow from a corresponding _ local _ version of the exclusion principle, applicable to such interacting systems.   our approach is very much inspired by the work of dyson and lenard ( see also @xcite ), who used only such a local form of the pauli principle to rigorously prove the stability of ordinary fermionic matter in the bulk ( the inequalities and were subsequently invented by lieb and thirringe to simplify their proof ). here   we show that the results are not only numerically weak, but also conceptually useful. as a result  , we learn something non - trivial about the elusive anyon gas.
wise j085510.83@xmath0071442.5 ( hereafter wise 0855@x math00714 ) is a recently discovered brown dwarf with a large proper motion.   it was identified as a high proper motion object by @xcite based on two epochs of images from the _ wide - field infrared survey explorer _ ( _ wise _, *?????? * ) satellite and its parallactic distance was measured at 4.5  in the near - infrared ( ir ) wavelength range. to improve its accuracy, we have obtained two new epochs using the _ spitzer space telescope s infrared array camera ( irac ; *????   * ) to measure astrometry for wise 08 55@x Math00714 in two additional dates, february 24 and july 1, 2014. during these observations,   the irac image quality was improved by reducing the exposure time for the individual frames from 26.8  s to 26.7  s and dithered frames from nine to five  s. the results show that the corrected basic calibrated data ( cbcd ) version of the individual [ 4.4.5
we investigate the existence of spatially compact spacelike cauchy hypersurfaces of constant mean curvature ( cmc ) in a vacuum cosmological spacetime.   we find that for any given constant @xmath0, there exists at most one compact cmc hypersurface with mean curvatures between@xmath = 0 and 0.1 such that the spacetime satisfies the timelike convergence condition. under the same conditions,   every maximal globally hyperbolic vacuum spacetime with a cmc foliation admits a global cmc slice, where the range of the means curvature ranges over the yamabe class of the cmc slices. by taking into account the presence of barriers, we show that this is not the case for all cases.
vibrating bed of powder is a vessel filled with granular matter, typically mono - disperse glass beads, and vessel is shaken vertically as strong as gravity acceleration.   when acceleration amplitude of vibration exceeds critical value, which is usually a little bit larger than gravity acceleration, the bed exhibits several instabilities, e.g., surface heaping, surface fluidization, and convection. in order to measure shear friction in this vibrating bed, akiyama and shimomura@xcite injected thick tube into vibratingbed and found vary surprising effect. with tube fixed in space, i.e., tube does not vibrate, the surface level inside tube differs from surface level outside tube, even if heaping is not observed without tube. in this paper, we reproduce this phenomenon numerically using distinct element method ( dem)@xcites. 	 we employ here non - spherical models introduced by pschel and buchholtz, which are known to reproduce static friction effect better than conventional models.    we find that surface level difference between inside and outside tube depends upon several physical parameters as diameter of tube, acceleration amplitude, and particle diameter. for each parameter,   the
cellular automata ( ca ) models for solar flares are successful in explaining solar flare statistics, but they are still in the state of rather qualitative flare scenarios.   the mhd and the ca approach to solar flares seem to have very little in common : the former are a set of partial differential equations, based on fluid - theory and maxwell s equations, whereas the latter are aset of abstract evolution rules, based ( in the case of solar flares ) on the analogy to critical phenomena in ( theoretical ) sand - piles. here  , we bridge the gap in - between these two approaches by re - interpreting the existing solar flare ca models so as to make them completely compatible with mhd calculations, and so that all relevant mhd variables are made available ( e.g.  the current and the electric field ). from the point of view of mhd, the main short - comings of the existing ca models are : ( 1 ) there is no control over consistency with maxwells equations ; ( 2 ) interpreting the vector - field in the ca models as the magnetic field leads to the problem that the gradient of the field ( @xmath0 ) can not be controlled ; ( 3 ) secondary quantities
we investigate the thermal conductivity of lif at temperatures and pressures relevant to high - pressure and temperature experiments using a combination of classical molecular dynamics and quantum monte carlo calculations.   we find that the heat capacity of lif increases linearly with pressure and is strongly dependent on the thermalconductivity of the lif window, where the quantum increase of heat capacity begins to be dominated by the decrease in conductivity due to umklapp scattering. for pressures up to 800   gpa @xcite, the thermodynamic properties of lif are best described by a phase coexistence method based on the density functional theory of the phonon density of states ( phdos ) and the radial distribution function computed with a potential tuned with ab initio data. as pressure increases,   the phdos of lif decreases and the onset of thermal instability is delayed until about 1.5 w / m - k near 20 k. these results are in good agreement with experimental data obtained from velocity interferometry measurements of the sound velocity and thermal conductivities of lif along the shock hugoniot at ambient pressure.
the remnant of the supernova sn  1006 ( rx  j1713.7@xmath03946 ), a bright supernova discovered in the rosat all - sky survey ( rass ; pfeffermann & aschenbach 1996 ), has been observed with the co satellite for cosmology and astrophysics ( asca ).   the x - ray spectrum of the remnant shows strong nonthermal emission from the limb - brightened regions along the western limb as well as weak nonthermally emissions from the rest of the interior. while the origin of this emission has long been suspected to be due to particle acceleration by shocks in the remnant, only recently has compelling evidence of such a process been observed.    we present new data from asca and co that reveal that the emission from g347.3@x Math00.5, a star - like remnant of sn  1016, is not due to particles accelerated by shock, but rather to electrons with energies up to 100  tev accelerated by the remnant blast wave.
the new generation of cosmic microwave background ( cmb ) experiments promises to estimate the cosmological parameters within a precision of 1%.   so far, all the estimations of these parameters based on the cmb data have assumed a gaussian distribution of the primordial temperature fluctuations. however, the gaussianity of the fluctuations is still to be fully tested and there exist several theoretical models which actually predict its violation. in this paper   i derive the dependence of four cosmological parameters on the skewness of the fluctuation field assuming a flat space. using the edgeworth expansion as a starting point  , i show that the likelihood function usually adopted in cmb studies is an offset log - normal function, which is an approximation to the exact likelihood that holds for gaussian data in presence of gaussian noise. when the variance of the perturbation is small, this problem is pushed many standard deviations away from the peak and does not affect the estimation of the parameter estimation. by contrast, if the variance is large, the likelihood estimates are affected by a non - zero skewwness, which can be explained by the existence of multiple sources of variation.
ab initio coupled - cluster theory is a promising method for the study of ground and excited states of nuclei in systems with many single - particle degrees of freedom.   it is based on the experience from quantum chemistry, where coupled cluster methods can be applied to large molecular systems with more than hundred correlated electrons, and we anticipate that quantum chemistry inspired coupled cluster approaches will enable accurate studies of ground- and excited - state properties of nuclear systems with dimensionalities beyond the capability of present shell - model approaches, typically limited today to systems with at most @xmath3 basis states. in this contribution   we present results of coupled cluster calculations for ground andexcited states of@xmath4he and @x math1o. using the coupled cluster method, we compare these calculations with exact diagonalization from shell -model studies within the same model spaces and with the same interaction. when possible, we also compare the results with those of shell - models by comparing the density functional theory ( dft ) calculations with the results obtained from coupled cluster simulations.
random privacy amplification based on the universal@xmath3 condition@xcite has been studied by many authors.   however, as the secrecy criterion, many papers in cryptography community dopt the half of the @xmath0 norm distance, which is also called the variation distance or eve s distinguishability. because this criterion is closely related to universally composable security @xcite, it is required to evaluate the leaked information from cryptography community viewpoint. in this paper, we adopt the @Xmm0 norm distances as the anonymity criterion, and evaluate the secrecy for random privacy amplification while hayashi@xaite adopts the mutual information criterion. in the independent and identical distributed case, when the rate of generating random numbers is smaller than the entropy of the original information source, it can be possible to generate the random variable whose @xmm0 norms distance to the uniform random number approaches zero asymptotically. in order to discuss the speed of this convergence, in the community of information theory, we often focus on the exponential rate of decrease. here  , we establish a systematic evaluating method for exponent for the @ xmm0norm distance in secure protocols.
we present a new model of chirally enhanced self - energies in the mssm for the sfermion - gaugino and fermion - higgs couplings.   this model is based on the fact that the quark self - energy is proportional to one chirality flipping element of the squark mass matrix and the quarks and gluinos are virtual particles which can be taken into account by taking into account the flavor changes due to bilinear terms, i.e. the effects of the yukawa couplings and the ckm elements. as a result   the self - energetic properties of the couplings are well known but the effect of the c km elements is still not well understood. in this article   we summarize recent progress in the field of chiral enhanced self-elements in the Mssm.
a light echo around the supernova sn1993j was observed in an hst wfpc2 observation of the spiral galaxy m81, 8.2 years after its explosion.   the light echo is visible in the b, v, and i bands ( f450w, f555w, and f814w ) of the wide field chip wf4 during our 2000 second hst observations with the very large baseline interferometer at 3.63 mpc ( @xmath2, freedman et al. 1994 ). for the distance to sn 1993j  , we use the distance from m81 to the nearest star, sn 1987a, as a proxy for the actual distance to this supernova. using the same approach, we find that the light echoes are scattered by dust which has been scattered by the nova light scattered by nearby dust, and that they can be detected by high - resoulution imaging.
we study the effects of fluid inertia on the swimming of linear chain structures, consisting of a number of small spheres and a single large one, in the stokes limit where inertia of the spheres and the fluid is neglected.   we find that for a linear chain of three identical spheres the optimal stroke, as derived from bilinear theory valid to second order in the amplitude of swimming, is nearly independent of the scale number which characterizes the effect of fluid inertiation. for chains of three smaller spheres and an additional large one   the same is true for chains with harmonic elastic interactions. using a cargo constraint we optimize the actuating forces subject to the cargo constraint but find that the latter does not lead to a significant decrease of swimming efficiency compared to the optimum value without the constraint.
the purpose of the present work is to formulate the 3-parameter family of difference maps ( dm ) in the  fourier domain with two oversampled coded diffraction patterns, but without any object domain constraint, and prove the uniqueness of fixed point after proper projection back to the object domain.   the motivation for coded measurement is to the unique uniqueness of phase retrieval solution as established in the douglas - rachford ( dr ) algorithm @xcite and the tremendous enhancement in numerical performance illustrated in the hybrid - projection - reflection ( hpr ) algorithm@xcite.
bose - einstein condensation ( bec ) in anharmonic trap is studied by using the potential harmonic expansion method.   the effect of the number of bosons in the condensate and the size of the trapped interacting bosons on the critical temperature and the fraction of the condensed gas has been studied. for a system of @xmath4 identical bosons interacting via two - body potential and confined in an external trap we adopt an ab - initio many - body technique which is known as potential harmonics expansion method ( phem ). to study the beyond mean - field effect of interaction and finite number of particles on the phase transition, we have used the correlated basis function which keeps all possible two-body correlations. from the results   it is shown that the critical temperatures for bec in the trap are much lower than those for the ideal bose gas ( ibg ).
we investigate a new type of modelling framework intended to describe the coevolution of sub - conscious attitudinal states and social tie strengths in a population of interacting agents.   our model is based on the notion of homophily and social influence, which are atomistic ingredients for models of social dynamics. using a set of observational observations, we show that people tend to modify their behaviour and attitudes in response to the opinions of others, sometimes even when this conflicts sharply with what they know to be true or believe to be morally justifiable.    we find that these changes are driven by a general class of activator - inhibitor processes, such as extraversion, impulsivity, neuroticism and anxiety, which form an independent set of dimensions along which different types of behaviour may be excited or regulated. from these dimensions, we develop a model of the evolution of attitude formation, which is driven by the activation of emotional responses mediated by the limbic system and the prefrontal cortex. under conditions of ` cultural drift ',   the state of each agent is more strongly influenced by social influence than by his or her internal state, and the strength of social influence increases with increasing social tie strength.see research article http://www.
a wealth of precision electromagnetic data, for single- and double - polarization observables, is anticipated from electromagnetic facilities worldwide over the coming months and years.   these data will be pivotal in determining the underlying amplitudes in complete experiments, and in discerning between various microscopic models of multichannel reaction theory. here  , we present multipole analyses of the single - pion photoproduction data using a parametrization form related to, but an improvement upon, previous said parametrized spectroscopic data,  @xcite.  the energy - dependent ( ed ) analysis is performed over the center - of - mass energy ( @xmath1 ) range from the near - threshold region to about 2.5  gev, including resonances through the fourth resonance region. with the help of single energy solutions ( ses ),   the data are fit over narrow energy bins assuming phase information obtained from the ed solutions. by employing the factor@xmath12^{-1}$ ] ( called the " hadronic rescattering matrix " ) in the photop reproducible model, we find that the number of multipoles per datum is better than any previously reported paramet
the tesla test facility ( ttf ) at desy @xcite has been working on the development of x - ray self amplified spontaneous emission free electron laser ( sase fel ).   the results have been obtained at the ttf using radiation pulses of 100 nm wavelength with sub-100 femtosecond pulse duration and peak power of approximately one gw. comparing to present day synchrotron radiation sources its spectral brightness is more than a 100 million times higher, the radiation has full transverse coherence and pulse duration is reduced from the 100 picoseconds down to 100 femtosing in time domain. these demonstrations have been made possible by the technique of self amplification of spontaneous emission through compression of electrons into volume small compared to the wavelength of radiation.
the magnetic phases of the hubbard model in the half - filled honeycomb lattice are studied.   the critical lines associated with instabilities of the paramagnetic phase are obtained in the @xmath5 plane ( interaction versus particle density ) and spiral spin phases are also considered. a ground state phase diagram containing ferro and antiferromagnetic order is obtained, where ferromagnetic regions with fully polarized spin are found in the vicinity of regions with smaller magnetization. at strong coupling, the spin wave dispersion obtained in random - phase - approximation ( rpa ) agrees with the holstein - primakoff theory for the heisenberg model ; at intermediate interactions, the rpa dispersion shows excellent agreement with experiment @xcite.
in the hot field of computer simulation of biological macromolecules, available potential energy functions are often not accurate enough to properly describe complex processes such as the folding of proteins @xcite. in order to improve the situation,   it is convenient to extract ab initio information from quantum mechanical calculations with the hope of being able to devise less computationally demanding methods that can be used to tackle large systems. in this work, we voluntarily circumscribe ourselves to the basic formalism needed for the ground - state quantum chemical calculations that are typically performed in this context.   we present in an axiomatic way the concepts and expressions related to the separation of the electronic and nuclear problems in the born - oppenheimer scheme. in particular, we introduce the molecular hamiltonian and a special set of units ( the atomic ones ) that are convenient to simplify the equations by getting rid of some constant factors that always appear grouped in the same ways and, thus, make the numerical values in any calculation of the order of unity easier to compute.    we also briefly review the variational method that underlies the derivation of the basic equations of the hartree and hartrees - fock approximations, discussed
the near - infrared integral - field spectroscopy of the binary star system @xmath0  ori  irs1 is reported.   the emission spectrum of the two components of the system, a and b, was studied by using the oh - suppressing infrared integral field spectrograph ( osiris ) at keck 2 telescope in the _ h_ and _ k_ bands with the nirc2 camera and natural guide star adaptive optics under non - photometric conditions. for both components, the absorption lines are strong br@xmath6 and t@x Math8, and the ratio spectra are consistent with the formation of a spectroscopic binary. to determine the orbit of components a andb, we used the same atmospheric absorption standard as the one used by @xcite to calibrate the flux calibration of the o9.5v star from the spectral library of @xcitesite. on the basis of the calibration results,   we propose that component a is a proplyd with an outflow phase of about 1.5  km / year, and that component b is a magnetically active low mass t tauri star.
in recent years, more and more effort has been devoted to finding and studying field theories which are candidates for effective descriptions of multiple m - branes.   the most promising candidate is the aharony - bergman - jafferis - maldacena ( abjm ) model, which is based on a chern - simons matter theory with @xmath0 supersymmetry and a topological gauge field with a natural action on the matter fields. in this review,   we present a description of self - dual strings using loop space in the context of the m2-brane models used as a guideline for the formulation of the basu - harvey equation that captures the dynamics of multi - m5-branes.see research article http://www.biomedcentral.com/1471-7007/1741-7006/9/11/8/10 for a full review of the literature on the use of loop space equations in string theory.
synchronization, i.e. the tendency of coupled oscillators to oscillate at the same frequency, is recognized as " one of the most pervasive drives in universe "  @xcite.   recently a synchronization regime of frequency locking without phase locking has been experimentally isolated in injected laser oscillators  . in this regime, the relative phase of two interacting oscillators is not constant in time, yet its variations are bounded, so that the systems keep oscillating at the exact same average frequency. here  , we show that this bounded - phase behavior is by no means specific to lasers, since it occurs also in models of circadian oscillators and in coupled van der pol oscillators. moreover, we find that the bounded - phases of driven oscillators are extremely generic, since they are associated to a hopf bifurcation point.
the texox-1000 ( toot ) radio source survey is the largest radio source redshift survey in existence that extends to high redshift and is unbiased by optical selection criteria.   it contains objects with l@xmath4 typical of 3cr galaxies at z@x Math10.3, allowing direct comparison of properties as a function of redshift without the usual problems of the redshift - luminosity degeneracy.
high - redshift radio galaxies ( hzrgs ) are rare objects in the cosmos, residing at the very brightest end of the radio luminosity function.   we have used deep, multifrequency radio maps of the botes  field ( @xcite ; s.  croft et  al., 2008 ;  ) to study the morphologies and properties of candidate hzrs that are fainter than " typical " hzRgs. using a cut in radio spectral index, @xmath6 ( @x Math7 ), we can preferentially select higher - redshifts objects, since a combination of intrinsic evolutionary effects and an observational " @x maths8-correction " tend to cause @x math6 to become steeper ( i.e., more negative ) with increasing redshift. by applying this cut to the westerbork synthesis radio telescope ( wsrt ) dataset of @xcites, we find that ~30% of the sources with@xmath9 and @xMath10mjy observed by @xaite were found to have @xmatrix@xXmath2. for most of these sources,
anderson localization theory predicts the absence of a disorder - driven metal - insulator transition for any degree of uncorrelated disorder.   recently, however, it has been reported that the presence of short or long - range correlations in disorder acts towards the appearance of truly delocalized states in one - dimensional ( 1d ) anderson models. in this paper  , we focus on the interplay between the delocalization effect, arising from the long - Range correlated disorder, and the dynamic localization, caused by an electric field acting on the system. by solving numerically the 2d time - dependent schrdinger equation for the complete hamiltonian, we compute the behavior of an initial gaussian wave packet in the presenceof a uniform electric field.    we find clear signatures of bloch - like oscillations of the wave packet between the two mobility edges of the phase of delocalised states.. the amplitude of the oscillatory motion of the centroid allows us to determine the bandwidth of the delocated phase.
theory of supersymmetry and effective physics are two of the most important topics in contemporary theoretical physics.   one of the main challenges is to derive a consistent higher - dimensional explanation for the chiral fermion spectrum and gauge symmetries of the standard model, and the other is to develop a robust and useful algorithm for extracting effective physics from generic supersymmetric _ mubrictheory orbifolds. in this paper  , we analyze and resolve the network of constraints which follow from the necessary requirement of gauge and gravitational anomaly cancellation point - wise in eleven dimensions in the class of models based on global orbifold compactifications of eleven - dimensional supergravity. 	 we focus on the @xmath1 holonomy constraint, which requires that some components of the 11-dimensional spinorial supercharge are preserved at each point in the space of global globular spheres. by resolving these constraints,   we gain insight into the physics corresponding to global@xmath0 hyperfine - tuning of the singularities of the three - dimensional quantum gravity ( e.g., #2, #3, and #4 ), and into the properties of the seven - dimensional continuum model @xcite.
the role of the neutron skin in the collective dynamics of very neutron rich nuclei @xcite is a subject of intense debate.   several experiments performed during the past 10 years reported the occurrence of an electric dipole ( @xmath8 ) response well below the giant dipole resonance ( gdr ), which manifests as a resonant - like shape exhausting few percentages of the dipolar energy wighted sum rule ( ewsr ) and its controversial nature attracted a considerable interest for theory too. in this paper   we address the connection between the development of the neutrons skin and the emergence of a low - energy @x Math8 response in relation with the symmetry energy density dependence, a subject under intense debate during the last few years.
we study the collective modes of a trapped boson - fermion mixture with attractive interactions using the equations of generalized hydrodynamics.   we consider a model for a dilute mixture of two species of alkali atoms inside harmonic traps, one species being spin - polarized fermions of mass and the other bosons of mass. in the collisional regime   the dynamics of the mixture is described by the equations on the basis of the equations for particle conservation, the quantum navier - stokes law, and the physics of gravity. to test the suitability of these equations for the case of attractive interactions we investigate the effects of the number of bosons on the frequencies of the first ten low - lying modes of the lowest - lying monopolar mode in the solution of the equation of general hydrodynamic equations of motion for a mixed mixture of 2rb-@xmath3k and 3k fermionic atoms.    we find that some modes undergo a blue shift which can become quite large at large numbers ofbosons, while some other modes display a softening which becomes pronounced in a very narrow window in the proximity to collapse.
the kinetic monte carlo ( kmc ) method is used to investigate the proton conductivity of a polycrystalline sample of the benzimidazole at the boiling temperature @xmath4 k. the model system is a chain of parallel rigid rods whose ends can be occupied by protons, one proton per end.   protons are passed by successive water molecules via the so - called grotthuss mechanism @xcite. in order to verify its usefulness,   proton transport results have been compared with the experimental data for a poly Crystalline samples of the benimidazodimethylamino-2-picrylhydrazyl ( bmdh ) and the phenylalanine ( pma ) compounds.
the regime of very low temperature, where a quantum mechanical description predicts only few quanta of mechanical motion, promises potential insight into some fundamental questions of decoherence, as well as various technical applications that make use of the expected quantum behavior @xcite.   we propose here a new approach to control the mechanical motion at the quantum level, if combined with the coupling to a high - q optical cavity mode and the application of suitable gradient fields. in this paper, we explicitly derive the fundamental mode properties of a nonlinear mechanical resonator, subject to the electrostatic gradient forces, to obtain a suitable model for the mechanical degree of freedom. using this model, we then derive the specifics of the optomechanical coupling to an optoelectromechanical system featuring a tunable mechanical nonlinearity per phonon and analyze possible source of damping and decoherent in detail. from these results  , we also summarize different control schemes, associated with suitable laser drives for the cavity and gradient fields from the tip electrodes, and discuss a readout scheme for the non linear mechanical resonators considered.
rxj0806.3 + 1527 is a remarkable object discovered during the rosat all - sky survey @xcite.   its soft x - ray flux is @xmath0 100% modulated with a period of 321.54s, which would imply a double - degenerate close binary system. as a crucial test to distinguish between the two scenarios we have started an abundance analysis of the optical spectrum presented by@xcite using a grid of theoretical spectra calculated with an nlte model atmosphere code for white dwarf photospheres with a range of effective temperatures, abundance ratios, and isotropic irradiation. here  , we present a study of the influence of the three main parameters on the spectrum.
reconfiguration of the terrestrial magnetosphere is a key process responsible for the energy transport and release of energetic particles.   substorm - like processes have been observed at jupiter by the particle and fields instruments onboard the galileo spacecraft @xcite. in this paper   we show for the first time observations of a tailward - moving loop - like magnetic structure ( tcr ) and plasmoids together with field - aligned beams and consider their features more detailed in the context of x - line reconnection using data from the epd and mag instruments on the galileso energetic particle detector ( epd ) and the magnetometer ( mag ), respectively. during the reconfiguration process   a bursty bulk flow of electrons and ions is released into the earth s magnetotail as a result of an x - type reconnection on the closed field lines in the near magnetotails.. the beam is accompanied by a large tailward moving plasmoid in the central plasma sheet which is driven by a rapid change of the flux tube volume outside the diffusion region. to study the dynamics of the beam we used the galiliary electron and ion field - alignment experiments on the ferromagnetic
the measurement of length by inertial observers in special relativity is one of the primary measurements in physics.   this measurement involves the determination of spatial distances and temporal durations that are associated with the effective establishment of a sufficiently local frame of reference. to determine these measurements,   it is necessary to give a theoretical description of the measurements of accelerated observers. here  , we review the basic concepts and terms about length measurement that are commonly used for inertial systems in special relativistic physics. using the hypothesis of locality, we show that the measurement of lengths by observers undergoing translational and rotational accelerations is independent of the position of an observer compared to all other observers in the same reference frame. under the lorentz transformations @xcite, time is frame dependent under the Lorentz - fitzgerald contraction, and the magnitude of the time difference between two observers depends on the relative velocity of the clocks and the relative position of the observers. when the observers are not at rest, however, the difference between the two observers is always greater than or equal to 1.5  s. the results of our study indicate that the experimentally measured length measurements of acceleration- and translational - induced accelerations
the aim of this article is to study the asymptotic properties of minimum contrast estimators ( mces ) of parameters of the gegenbauer random fields.   the mce methodology has been widely applied in different statistical frameworks, including the estimation of spectral densities of stationary processes with singularities of the spectral density at non - zero frequencies. for cyclical long - memory processes or long - range dependent random fields,   a variety of mces have been proposed and validated using the whittle maximum likelihood estimation method. here   we review the results of the work by @xcite and @xmath1 grid on the use of mce for the parameter estimation of stationary gegensbauer spatial processes.
we present new beryllium and oxygen abundances in old disk - population f - type field stars with available lithium measurements.   these objects are slightly evolved off the main sequence, and are mainly located in the effective temperature range for which a strong lithium depletion, the so called " li gap ", is observed among cluster and field stars older than @xmath0 yr. while the initial or " cosmic " lithium abundance of these F - type stars can be traced back to the evolution of ( _ p,@xmath1 _ ) nuclear reactions, the extent of the li gap is not well understood. here   we show that the surface abundances of the two elements, be and li, are much lower than expected from their different nuclear reaction temperatures, and that they are also depleted by a strong reduction in the active temperature of the stellar interior when the temperature in the interior reaches / = 0.9 to 1.7 k. the results are consistent with the hypothesis that the high levels of fragility of be and Li make them more easily destroyed by nuclear reactions than oxygen, while the low levels of oxygen could be affected by transport mechanisms associated with microscopic diffusion
during the recent gregorian upgrade of the arecibo telescope, we have confirmed eight new pulsars in the 430-mhz region of the sky ( @xmath0 ).   these pulsars are weak sources with typical flux densities of order 0.5 to 1 mjy and their positions are presently uncertain by of order@xmath4 arcmin in right ascension and declination  equivalent to the half power beam size of the telescope at 430 mhz.
the nature of the soft x - ray absorption observed in long - duration gamma - ray bursts ( grbs ) is one of the outstanding puzzles in understanding the origin of the afterglows.   it has been assumed from the beginning that the soft X - ray opacity observed in the majority of grb afterglow spectra is due to photoelectric absorption by the inner shells of the atoms in a column of metals in the host galaxy of the grb, in a fashion directly comparable to the x -ray absorption observed due to gas in the galaxy. however, recent studies have shown that the observed x - rays appear to increase with redshift, with the highest column density objects appearing at the highest redshifts, and no comparably high column densities occurring at low redsh shifts. here   we investigate the nature of this apparent increase in absorption, the claim of a possible detection of a warm - hot intergalactic medium, and the role of dust extinction in the mechanism of the observed increases in absorption. for each grb in this set with a known redshift  , we used the spectra produced by the auto - analysis of @xcite with the corresponding response files and fit a model
in - network function computation is one of the fundamental paradigms that increases the efficiency of sensor networks vs - a - vs conventional data networks.   our focus in this paper is to develop a queue - based framework for such systems, and use it to design and analyze network algorithms. by network algorithms,   we refer to cross layer algorithms that jointly perform the following tasks :   aggregating the data at nodes via in - network computation,   routing packets between nodes, and   scheduling links between nodes for packet transmission. here  , we show that the proposed framework is suitable for designing network algorithms that are dynamic, robust, capable of dealing with a large class of functions, and generalizable to all network topologies.
yy geminorum, ( bd + 32 1582, sao 60199, gliese 278c ) is a short period ( 19.54 hours ) eclipsing binary with two almost identical dm1e ( flare star ) components.   the close binary is a subsystem of the nearby castor multiple star ( yy gem = castor c ), at a distance of @xmath314.9 pc. here   we review the photometric observations of repetitive, apparently periodic, flares on yy gems during the x - ray and uv observations of the castor system during the 2009 japanese Astronomy Centre ( vla ) programme. in particular, we examine the effects of surface inhomogeneities ( starspots ) on the observed brightness of both components, which are thought to be caused by magnetic reconnection between loops on the two stars generating interbinary flares. using data from the vla, we show that the mean mass and radius of the two components are about 70% of each other, with the outer 30% of the convective zone being the most active region. these results are consistent with the previously reported values for the intrinsic luminosities of the systems.
the detection of cherenkov radiation from atmospheric cascades initiated by high energy particles has been considered as a potentially promising method for high energy @xmath0-ray astronomy since the fifties.   however, the main limiting factor limiting the sensitivities of ground - based observatories which utilize this method is the high rate of the cosmic ray background events. in this paper   we explore a new discrimination technique that is characterized by efficiency @x Math17 in addition to the already existing methods of background suppression achieved by imposing shape and orientation cuts.the proposed discrimination technique is based on the differences in intrinsic fluctuations of cherenekov radiation produced in the pure electromagnetic and hadronic cascades. using the maximum likelihood approach based on an analysis of the@xmath18 functional to establish discrimination criteria to distinguish showers initiated by @x math0-rays from those initiated by cosmic ray nuclei  , we show that it is possible to identify the primary photon in most of the hadronic showers with an efficiency of @x maths17 ( ~2.5 ) and the existence of a source is established if the background is rejected by the use of the new discrimination procedure when the number of events produced by a hypothetic source
we describe a simple laboratory experiment to detect the planet orbiting around the star, hd  209458.   the experiment is aimed at advanced secondary school students and is based upon that of laboratory aimed at 1st year undergraduates at the university of birmingham. in this experiment   we use observations made of the brightness of the star over a 7 hour period to infer the properties of the planet rotating around it. by measuring the variation in the time of the transit between the star and the planet, we can determine the planet s mass and radius using the doppler wobble method @xcite.the experiment introduces to the student kepler s laws, orbital mechanics, data handling, error analysis, and current astrophysics topics.
the energy of charged particles can increase as a power law in time in a simple helical magnetic field, whose components are slowly varying sinusoidal functions of both space and time.   this process can lead to an indefinite energization of a charged particle to relativistic energies, given enough time.
the solar neutrino puzzle ( snp ) and the lsnd anomaly ( la ) are two of the most difficult problems to solve with only three neutrinos.   it has been recently pointed out that there is another way to address these problems : cpt violation. in this article,   i argue that the snp and the la probably can not be solved in a satisfactory way by assuming the existence of a " cpt violating ether ", which modifies the oscillation probabilities of neutrines and antineutrinos in distinct ways. using a two - flavor analysis  , i show that the current data already set very strong limits on particular cpt violate operators @xcite, while potentially stronger limits may be imposed by future experiments.
matrix theory is a powerful tool for understanding the nonperturbative structure of string / m - theory.   it can be used to study the dynamics of test particles, thermodynamics, decay via the hawking process, etc. in this paper  , we review the results of matrix theory calculations of five - dimensional ( near)bps black holes using supergravitons as probes of the geometry of 11d supergravity on @xcite-@xcite, and show how matrix theory reproduces various asymptotic features of the metric. by adapting a d - brane calculation of maldacena @xmathite, we reproduce in section 3 the near - extremal black hole entropy as the entropy of the noncritical string theory that describes matrix theory from the standpoint of string theory. rephrasing the calculation in natural m - theories variables   renders the interpretation of many formulae transparent.. the basic theme will be that black hole thermodynamics is generalized supersymmetric yang - mills statistical mechanics, in the microcanonical ensemble.
the rhic experimental program at the synchrotron center for quantum chemistry ( rhic ) is now in its second year of operation.   the main goals of the rhic program are to produce and characterize the quark - gluon plasma ( qgp ) and to study the effects of jet quenching and other " hard " probes on the qgp, such as the hadronic gas @xcite and the prompt photons which are produced during the initial collisions of the partons which constitute the heavy ions being collided.
infrared luminous galaxies ( irlgs ) are a significant population at the bright end of galaxy luminosity function.   two types of activity, active galactic nucleus ( agn ) and starburst, are thought to contribute to the far - infrared emission of irlg luminosities : starburst and active galactic nuclei. in this paper  , we use the polycyclic aromatic hydrocarbon ( pah ) emission feature at 7.7 @xmath0 m to estimate the relative importance of these two kinds of activity in the far- and near - infrared luminosites of iras 05189@xmath102524, one of the most abundant irlgas in the region 34 @x Maths 0.5 to 0.8 km from the equator. using the spectrum of an extended version of the _ infrared space observatory _ ( _ iso _ spectra at 5.811.6 @x maths0 m, we show that the observed ratios between the 7.4 @x math0.8 m pah emission peak flux and the total continuum flux of the 13.1 @x mathematics0.9 m pahs are roughly half of those of starburst
microlensing of stars in the magellanic clouds has revealed a population of compact objects in front of the lmc.   the nature of dark matter in the galactic halo is still uncertain, but recent studies have shown that it is likely to be more than 10% of the mass fraction in machos in the halo. here   we address the question of what would be the observational consequences if this dark matter were also composed of compact object dark matter. using microlensing data from a monitoring program of quasars behind the virgo cluster, we investigate the effect of compact matter on the surface brightness distributions of distant galaxies observed through galaxy clusters whose dark matter is composed of machos. by focusing on the giant arc seen in the cluster abell 370, we show that the magnitude of the induced variability can be increased by changing the lensing geometry and considering clusters at higher redshift. as an illustration of the efficiency of microlensions as a mechanism for introducing variability, we present a case study of the giant arcs seen in abell370. while the optical depth of the cluster is quite small, the resulting low - level fluctuations, @xmath4, are observable, and these are expected
work is a fundamental property of quantum systems and is one of the cornerstones of thermodynamics.   it is meant to characterize a process rather than an instantaneous state of a system @xcite. in classical systems work is determined by two projective measurements of energy at the end and the beginning of the force protocol, i.e., the energy difference definition (  ) and the power based approach (  ). however, for a quantum system the back - action of the measurement device modifies the state of the system ; it consequently influences the outcome of a subsequent contact, therefore influencing the final value of the work @xcites.    the paper presents a theoretical foundation of what work means in quantum mechanics and how it can be defined in an operational way.
we have developed a pseudo - spectral numerical algorithm for simulating accretion disks around black holes in two and three dimensions.   the algorithm is based on a set of orthogonal modes, which are solved in terms of the vector potential and not of the magnetic field itself ; this ensures that the resulting magnetic field is divergence free.. the results show that the proposed algorithm is able to reproduce the oscillatory behavior of hydrodynamic and magnetic - hole - deltoid ( mhd ) accretion disk flows in both two and 3 dimensions with high accuracy and economy, and it also shows the presence of all three types of trapped global modes that were discovered analytically.
the fulde - ferrell - larkin - ovchinnikov ( fflo ) state is predicted for clean spin - singlet superconductors as a result of the competition between pairing correlations, favoring anti - parallel spin alignment, and the zeeman effect.   the transition from the normal to superconducting state changes from second - order to first order below the temperature @xmath5 or@xmath6, depending on the field orientation. in this study, we investigate the existence of the fflo state in the quasi - two - dimensional ( 2d ) material cecoin@x Math0.1 with respect to the intrinsic anisotropy of the order parameter. using a combination of x - ray crystallography and density functional theory calculations, we show that the upper critical field of the self - consistently quasi-2d fflo phase is at least twice as large as that of the nonuniform phase. by varying the orbital critical field to the pauli critical field,   it is possible to observe a change in the order of the transition which is consistent with the presence of vortices within the superconduction state.
we study the infrared behavior of the pressure in the @xmath0 scalar theory in six dimensions using the modified self - consistent resummation ( mscr ).   we show that only one recalculation of the self - energy is enough to obtain an infrared divergent free result, which is independent of the temperature dependent infrared divergences arising in the perturbative expansion. under two approximations,   the pressure is found to be of a finite value.
the " snapshot of foundational attitudes toward quantum mechanics " taken by schlosshauer, kofler, and zeilinger ( skz ) and shared in ref.@xcite attracted a surprising amount of attention in both the scientific and popular media.   apparently many people regard it as interesting and perhaps surprising that simple, seemingly elementary questions about the meaning and implications of the ( now - almost-100-years - old ) quantum theory could remain unresolved and indeed hotly contested. with the hope, not so much of finding a " truly representative sample" but rather simply of demonstrating the existence ( and prevalence ) of different viewpoints, not well represented in the original survey, we arranged to give the same poll to the attendees at another recent quantum foundations conference : " quantum theory without observers iii" held in bielefeld, germany in late april ( 2013 ). for each question, the bar graph indicates the percentage of respondents who endorsed the given options.    afterwards we indicate the fraction of respondentswho made comments in the margin ( which is perhaps some kind of measure of how problematic people found the question and/or the proposed answers to be ) and quote any particularly interesting or noteworthy or common comments and write -
abstractthe distribution of points rationed on the basis of algbriques is a classique of the diophantienne.   it is well known that most of the varits do nt agree with the principle of batyrev - manin, as measured by the constant of peyre @xcite, and many of the more complex varits ( e.g., the torques ). in this article, s. pagelot and m. roth have compared the distributions of these varits using a new method of calculation, based on the density of a dense point rationing distribution, to those of the existing ones.
the glauber model is a semi classical model picturing the nuclei moving in a straight line trajectory along the collision direction and describes nucleus - nucleus interaction.   it is used to extract the radii of unstable nuclei from measured total or reaction cross sections for many cases of stable nuclei. here   we present a systematic calculation of reaction cross section using the coulomb modified glaubers model ( cmgm ) and elastic scattering angular distributions for pp and np collisions at incident energies ranging from 124 to 1120 mev. with the use of three parameter fermi density ( 3pf ) in contrast to 2pf density and gaussian densities used in previous studies, the reaction crosssection and the elastic scatteringangular distributions are obtained at many energies and are compared with the data to test the reliability of the model and the input parameters for many case of stableuclei.    the results show that the model gives the probability for occurrence of a nucleon - nucleon collision when the nucleari @xmath6 and@xmath7 are in a non eikonal trajectory and the real part of the scattering amplitudes are taken as double folding potential.
the infrared structure of massless quantum electrodynamics in three dimensions ( qed3 ) is an old problem  @xcite.   it is widely believed that the theory is characterized by confinement of charge, with a concomitant dynamical mass for the fermions. here   we explore this question via the renormalization group, guided by our knowledge of four - dimensional non - abelian gauge theories. using the schrdinger functional scheme  , we show that the scale of the coupling @xmath4 is governed by the beta function,@xmath5 where @x Math6 is the one - loop coefficient. upon defining a dimensionless coupling @Xmath7, we have @x math8, a form typical of a super - renormalizable field theory.. the running of the coulomb interaction @x maths10 is dominated by the first term, which has the sign associated with asymptotic freedom in four dimensions. when the coupling becomes large enough, but before the second term becomes important, a condensate @xMath12 forms, whereupon at sufficiently small energy scales the fermanions drop out of the theory, leaving free photons.
gravitational microlensing is a technique that uses gravitational lensing to detect the presence of gravitational effects on background stars.   it is being used to search for galactic dark matter in the form of massive compact halo objects ( machos ), which are thought to be made of baryonic matter. at the time of the writing ( fall 1998 ),   the total number of reported microlense events exceeds 300, and the overwhelming majority are seen towards the galactic center. here   we review the history of microlensing and discuss the current state of the field.
the authors of refs.   @xcite have argued that the existence of octupole deformation in the nuclei of light actinides enhances the sensitivity of atomic dipole moments to nuclear parity and time - reversal symmetry violation by factors of 100 to 1000 over the sensitivity in the atom with the best current experimental limit, @xmath0hg. here   we give a pedagogical derivation of the schiff operator, explore its action on nuclear ground states, and address the role of Octupole correlations in generating ground - state schiff moments.we find no flaw in the argument that moments in such nuclei are collective and enhanced, but point to physics that may make the enhancement less dramatic than claimed in refs..@xcite.
physical layer security in wireless networks has been mainly focused on higher layers using cryptographic methods.   very recently, physical layer security have been generalized to investigate wireless fading channels and various multiple access scenarios. in this review,   the authors propose a non - jamming relay selection scheme for two - way networks with multiple decode - and - forward relays in an environment without eavesdroppers, which maximizes the worse received signal - to - noise ratio ( snr ) of the two end users by effectively " jamming " the eavesdropper. as a proof of concept, we investigated the effects of user cooperation on the secrecy of broadcast channels by considering a cooperative relay broadcast channel, and showed that user cooperation can increase the achievable secrecy region.
the baldwin effect ( beff ) is a strong anti - correlation between the equivalent width of broad emission lines ( bels ) and the continuum luminosity, @xmath15, measured at 1450 in the quasar rest - frame.   this correlation can be used to test model predictions for the dependence of the shape of the continuum spectral energy distribution as a function of luminosity. however, the physical cause of the beff remains unknown. here   we show that the strength of the relationship seems to depend on the ionization energy of the emission - line species, and that it decreases more dramatically with @x Math15 than with other emission lines with moderate ionization energies like iv civ@xmath6 or low ionization energetics like mgii@x math16 and balmer emission lines. using a new accretion disc model, we find that the slope of the @x maths14  =  @xMath15 anti - correlations depends on the size of the emissive cloud, which is determined by the distance between the central continuum source and the emission line region, and the number of hydrogen ionizing photons emitted per second by the emitting continuum source. when the distance from the central
the discovery of five super - earths ( a class defined as having a mass between 1 - 10 earth - masses ) has led to the idea that there might be more than one type of terrestrial planet in our solar system.   plate tectonics is the only mode of convection that has been proposed as a required mechanism for life on earth. here   we show that the conditions for deformation and subduction are easily met by planets more massive than earth, using detailed models of the internal structure of massive terrestrial planets and parameterized convection models. however, the temperature at which the plate cools enough to develop negative buoyancy at subduction zones is not necessary for subduction.
evolutionary game theory ( e.g. evolutionary game theory ) has been widely used to study the evolution of cooperation in scale - free networks.   the recent shift from evolutionary games on regular grids to evolutionary games for complex networks can be considered a step towards more realistic conditions, as well as an important realization that the outcome of evolutionary games in structured populations can be very different from the well - mixed case. here  , we review the current literature on the impact of spatial structure and interaction topologies on the social fate of cooperators and defectors in the stag - hunt game, which together with the prisoner s dilemma and the snowdrift game, forms the standard set of social dilemmas that is frequently explored in the present literature.    we also discuss the implications of these studies for the development of new strategies aimed at promoting cooperation in evolutionary games.
the effects of dark - matter ( dm ) decay on recombination, reionization, and heating of the intergalactic medium, as well as their subsequent impact on the central microwave anisotropy probe ( cmb ) temperature and polarization power spectra, are investigated in this work.   we use the currently available cmb data, including the first - year wmap data, which show a large temperature - polarization cross - correlation, to constrain the ionization history of decaying dm. using these data, we find that the rate at which dm decay releases energy into the baryonic gas during recombination is much slower than expected from the decay width ( inverse lifetime ) of the decay particle, and the effect of heating / ionization on the cmb temperature spectrum is much larger than expected. with the addition of the large - scale - structure ( lss ) survey data from the sdss and 2df @xcite galaxy surveys, we derive more stringent constraints to the decay of the dark matter particle, but the results are still in line with the conventional reionized scenario.
tin dioxide ( sno@xmath2 ) is one of the most used and interesting materials for the development of solid state gas sensors, transparent conductors, and catalysts.   many physical properties of this and other oxides are driven by defects which are mostly due to the ease with which the oxygen content can be varied. in this paper, we report on a first - principles study of the electronic and structural properties of tin dioxide crystal and surfaces in the presence of oxygen vacancies both in the bulk crystal and at surface and subsurface sites, focusing on the effects on the energy levels close to the fermi energy. accurate calculations of the electron band structure have been done within an all - electron approach, which employs the hybrid b3lyp exchange - correlation functional.electron affinities have been studied with pseudopotential plane - wave calculations.
the charged vector meson condensation above the critical magnetic field was suggested in hadronic models @xcite.   this condensation was also discussed in more microscopic theories, such as the extended nambu  jona - lasinio model ( njl )  , the lattice qcd simulation@xcite, and models of the gauge / gravity correspondence . in this paper, we discuss the possibility of the charge - vector mesons condensation in qcd in a strong magnetic field, and analytically show that the condensation does not occur in a magnetic field. when the strength of a magnetic fields exceeds the qcd scale, internal structures of hadrons are important. for these cases,   the vafa - witten theorem is used to show that any global - internal symmetry is not spontaneously broken by an external magnetic field.graphical abstract
ferrofluids are colloidal suspensions of magnetic monodomains in a non - magnetic carrier liquid @xcite.   they behave like a super - paramagnetic substance, which allows for a wide range of applications, and a peculiar flow behavior under the influence of external magnetic fields. here   we present an experimental investigation of the nonlinear oscillations of the free surface of a ferrofluid by making use of the technical advantage that hydrodynamic motion can be induced by time dependent magnetic fields.the results show that the field induced surface deforming instabilities are characterized by a bifurcation scenario of the oscillations, which falls into a class which has never been studied experimentally. to capture the main features of the experimental findings we discuss the results in terms of a qualitative model which is based on a qualitative analysis of the experiments.
astrometric space missions, especially the esa ( european space agency ) cornerstone mission gaia, are in preparation to attain microarcsecond ( @xmath2 ) level of accuracy in absolute positional measurements of stars and other celestial objects.   this unprecedented accuracy of astrometric observations makes it necessary to account for many subtle effects which were totally negligible before. among them   is the gravitational light deflection of one companion of a binary system in the gravitational field of the other companion. here   we present a new method for estimating the probability for the occurrence of edge - on binary systems which have a given light deflected depending on their orbital parameters like inclination, mass, distance and semi - major axis. as it has been shown by _   klioner, et al. since the inclinations of binary systems are of course randomly distributed, such an inclination formula can be obtained by means of the analytical solution of lightdeflection in standard post - newtonian approach.. the proposed method is applied to estimate the number of relevant edge -on binary systems with a Given Light Deflection of about @x Math2. using this method  , we find that there are at least a
the kolmogorov equations are a set of equations that describe the stochastic dynamics of a network.   they are known to be very difficult to solve numerically because of the large number of equations and the fact that they are not exact in the sense that they can only be approximations to the exact process unfolding on a homogeneous random graph. here   we present an approach to derive approximate models for the moments of the sto chastic process using low - dimensional odes, in particular those that capture the dynamics of the network as a function of the time scales of the kol mogorova equations.    we use two important examples from epidemiology and a recent model of a dynamic network where links can be activated and deleted at random while subjected to a global constraint on the total number of links in the network to demonstrate the applicability of this approach.
we study the effects of metallicity on the orbital period of stars in the lower main sequence of the solar system.   we use the theoretical relation between mass and absolute @xmath2-band magnitude,  to calculate the orbital periods of field stars of spectral types k / m supplemented by the sun for a series of young disk ( yd ) field stars from l96, the yd binary yy gem (@xmath7 ), the sun, and 56 stars with radii from . using the observed radii, we have established a radius scale which allows to estimate the radii of field star of given @x Math3. using these results, we construct a diagram for field stars predicting the orbitalperiod of a cv at which a field star would fill the roche - lobe of the secondary if it were to be of given spectral type. as a result  , we find that the radial distribution of the field stars varies with the age of the primary and with the number of solar metalloids present in the secondary. among the young disk field stars,   the most important effect is the change in the orbit of
maritime transportation plays an important role in the world merchandize trade and economics development.   we present an empirical study of the worldwide maritime transportation network ( wmn ) using two different network representations and analyze basic topological properties including degree distribution, degree correlations, shortest path length, weight distribution and strength distribution etc.we get the original data from a maritime transport business database named ci - online @xcite which provides ports and fleet statistics of 434 ship companies in the global maritime transport network.    the data includes 878 sea ports and 1802 lines with unbalanced geographical distribution mainly located in asia and europe, including 13 ports in asian and middle east, 1 in africa, 9 in europe,1 in north america and 1 in latin america. 	 the most connected ports are located along the east - west lines. ipsilateral to the hub ports, lateral ports, main lines and branch lines form a complex container transportation network system called hub - and - spoke operating structure which consists of hub port, lateral port, main line, branch line and branch line networks. by studying the weighted and unweighted clustering and degree correlations  , we find that
wireless sensor networks are one of the most promising areas of research in the field of sensing and computing.   each node in a wireless sensor network has its own limitations i.e. it must be capable of sensing, processing and transmitting/ receiving data. to cope with these limitations,   many algorithms have been developed to deal with power constraints. however, there is always a room for betterment. in this paper, we discuss about the work done on cluster based routing of wireless sensors along with areas which need modifications to enhance efficiency. among them, we focus on efficient routing protocol that has low routing overhead and well organized data aggregation mechanisms to increase good put of network and to save limited power of sensor node.
the alignment effect of the optical polarisation vectors from distant quasars is a well - known phenomenon.   the strength of the alignment and the significance of the effect depend on the choice of the spherical coordinate system, so that it is possible to find an axis for which the effect becomes negligible in some regions of the sky defined by cuts on right ascension and redshift. here  , we propose a new statistical method for the analysis of this effect, which is independent of the coordinate system and allows us to compare the polarization vectors of sources located at different angular coordinates and leads to the characterization of the signal through a blind analysis of the data. using this method,   we show that the alignment effect can be quantified unambiguously in regions where the data look random, and we also show that there is a cosmological alignment between the two most significant regions.
the neutrino magnetic moment has been the subject of intense theoretical speculations for many years.   it was originally put forth in the early 1970 s as a possible explanation to the solar neutrinos'disappearance from the solar magnetic field, which was thought to be due to a spin precession in the magnetization of the neutron antineutrino, @xmath0. here   we reexamine this idea and find that the proposed mechanism works only for small flavor mixing. in the case of the radiative zone ( rz ) of the sun,   the usual treatment, based on the@xmath3 resonance, works only at the level of small flavor Mixing ; the large measured value of the rz neutrin mixing angle leads to a qualitatively new effect : the resonant level crossing disappears and no measurable magnetic spin flip can take place.see research article http://www.biomedcentral.com/1471-7007/9/17.
in the present lectures, i review the dynamics of a bose - condensed gas at finite temperatures, when there is a large number of atoms in the non - condensate.   the first half of these lectures deals with excitations in the collision - dominated hydrodynamic region, which are self - consistent mean fields ( of various kinds!)the second half of the lectures focuses on excitations whose very existence depends on self - inconsistent mean fields, rather than on the collisions between atoms. for a uniform bose-condensed gas, the excitation frequencies are those first discussed by bogoliubov in 1947 @xcite. in this context, the main topic will be to review our understanding of what excitations are in a bosing - condensed water at finite temperature.. the second half and the third half of each lecture will focus on excisations in the collaterals - dominated two - fluid hydrodynamics, generalized to include a trapped bose gas. here  , i give an explicit microscopic derivation of the two - fluids equations given by landau@xcite and zaremba, griffin and nikuni ( zgn ), and discuss the role of the
the milky way is the galaxy of the local group whose global stellar populations are least well observed.   we have conducted a wide - field, high - resolution, sensitive survey of the k band of the near - infrared and x - ray parts of the electromagnetic spectrum in the sciii galaxy ngc 2403 ( @xcite ) to detect and characterize at least 90% of the wolf - rayet stars in this region of the galaxy. using a new narrow - band survey, described in @xmath6  along with the candidate selection methods, we have found 41 new wolf - Rayet stars : 15 nitrogen- and 26 carbon-star - like objects from the 2mass@xcite and glimpse surveys. as they have relatively short lifetimes ( about ~5 years ),   these stars are excellent tracers of star formation, and they are also believed to be type ib or ic supernova progenitors.
when a wave propagates with a low energy in a quasi - one - dimensional ( q1d ) wave guide with an uniform cross section, the guide is effectively one - dimension ( 1d ) since only the first transverse mode plays a role.   however, when a guide comprises discontinuities such as bends and branching junctions, higher transverse modes come into play at the vicinity of the discontinuies.. therefore, in principle, a full - mode or full - wave analysis is required to analyze the wave propagation in the guide.    it is the purpose of this paper to present a scheme to eliminate those redundancies and simplify the calculations, yet have those low - energy properties faithfully preserved. for a particular discontinuity, the scattering matrix ( @xmath1-matrix )   is evaluated using a whole - wave treatment, and then the matrix is truncated leaving only those elements relating the firsttransverse modes in the branch guides. from the truncated matrix, the reduced equations relating the wave functions and their first derivatives on the lines connected to a junction   are derived and used to connect the 1d wave functions in reduced systems. by means of the connecting equations,
molecular hydrogen ( h@xmath0 ) is by far the most abundant molecule in the interstellar medium, followed by carbon monoxide ( co ) with a significantly smaller amount.   the symmetry of h@Xmath0 results in the absence of a permanent dipole momentum, which makes the dominant interstellar molecule very difficult to detect. for this method   it is necessary to know the conversion factor @xmath7 between h@ xmath0 column density and the velocity - integrated @x Math5co emission temperature, defined as @x math8co@x maths9h@xMath10co@ Xmath11.    the data obtained from the heidelberg - tbingen echelle spectrometer during the _ orfeus ii _ mission on the _ astro - spas _ space shuttle mission provide the first opportunity to determine a h@axmath0/co ratio for lmc gas directly.. the analysis of the absorption spectrum of lh 10:3120 shows a column density high enough to expect the presence of co.
the jaynes - cummings - hubbard ( jch ) model is a new framework for studying quantum many - body phenomena such as phase transitions where strongly correlated photons play the role.   it describes a two - state atom ( qubit ) coupled to a single field mode within a highly reflective cavity and it is exactly solvable, within the rotating - wave approximation. here  , we investigate the propagation dynamics of single excitations in an array of coupled cavities, each containing a single two - level atom, using the jch model. by considering a staggered pattern of hopping rates, instead of uniform, a gapped discrete field normal frequency in the middle of the band   is induced, corresponding to a strongly localized field normal mode. by setting the appropriate parameters,   a significant atom - field interaction can persist even if we increase the system size and thus the atomic excitation is no longer frozen. at the same time, the photonic excitation can be transferred from one cavity to another, either by direct hopping or by energy exchange with the resonant mode.. the results indicate that even in the single excitation subspace, the jc model presents an appealing dynamics due to the
we derive the combined l-@xmath13 distribution function for the gamma - ray burst rate, @xmath19, in the uniform jet model.   we estimate the luminosity function by fitting the observed peak flux distribution using a simple parametrization of this function. when considering the angular distribution we also examine the universal structured jet ( usj ) model and show that the implied peak flux distributions are somewhat inconsistent with the observed one, with the problem most severe at the low end of the peak luminosity distribution.
the merging galaxy l@xmath0 = 3.5 @xmath1 10@x Math2 @xcite is a luminous infrared galaxy with an active galactic nucleus ( agn ) in its nuclear region.   the merging galaxy has a large far - infrared ( fir ) luminosity and is thought to be dominated by starburst activity induced by galaxy - galaxy interactions. here  , we present european vlbi network ( evn ) observations at 1.6, 2.2, 5.0 and 8.4 ghz using the nrao very long baseline array ( vlba ) to image the compact radio sources of this merging galaxy. among the new sources,   two have been identified as high - brightness nuclei with a peak central structure surrounded by weak additional components possibly related to starformation. both high - brighter nuclei show an inverted spectrum at lower frequency with a spectral turn - over or flatness due to free - free absorption ( ffa ) or possibly synchrotron - self absorption ( ssa ) from the intervening hot ( obscuring ) dust at longer wavelengths @xcite. strong h@x math9o@
non - equilibrium statistical mechanics has found unusual applications in research on traffic flow of various different types of objects.   the aim of this article is to summarize the main results of recent works on all the three systems mentioned above, elucidating the nature of various types of quenched randomness, to present the challenging open problems, and to indicate the possible trends of future developments in this frontier area of interdisciplinary research.
spin - orbit ( so ) coupling has been proposed as a mechanism for the quantum spin hall effect in atomic quantum gases with gauge fields.   the inclusion of so coupling induces competition with spin - dependent interactions in addition to modifying the single particle spectra for a spinor bec, where the two ground state phases are ferromagnetic and polar. here  , we investigate the formation of ground state patterns in a spin-2 bec with so coupling in a quasi - two dimensional optical trap @xmath1 with a plane - wave laser beam setup. depending on the sign of the effective spin interaction strength, which is proportional to the difference between intra- and inter - species atomic scattering strengths, either planar or standing waves   are found to be formed in the ground state. by taking into account the fact that the effective hamiltonian takes the form of a reduced two - dimensional effective density - density,   we find that the ground states can be classified into two types : planar and standing waves.
the cosmic censorship conjecture ( ccc ) articulated by penrose @xcite is fundamental to many aspects of theory and astrophysical applications of black hole physics today.   however, despite many attempts over past decades no theoretical proof or even any satisfactory mathematical formulation of ccc is available as of today in the case of dynamical gravitational collapse. here   we consider the gravitational collapse of a perfect fluid with a linear isentropic equation of state in the framework of general relativity and show that the occurrence of black holes and naked singularities evolving from regular initial data depends on the choice of rest of the free functions available. for a given spacetime dimension and for a critical positive tangent to the singularity curve,   the existence of a naked singularity can be removed when one goes to a higher dimensional spacetime, thus restoring ccc.
the super - eddington luminosity is one of the long standing problems in the theoretical study of classical novae.   recently, @xcite presented a model for the super -Eddington phase for five galactic novae, v693 cra, v1974 cyg, v1668 cyG, v351 pup, and os, and reproduced the 1455    continuum light curve of v 1974 cyg. in the present paper, we apply the same method to other classical nova outbursts to examine whether or not this idea is applicable to the different speed class of novae ( e.g., a faster nova shows a shorter duration of the uv outburst ). by using the time - resolved uv light curves of these novae  , we show that the reduced opacity in the early phases of the nova decay can be used to estimate the white dwarf mass and distance to the star@xcite.
a model independent analysis of the flavor off - diagonal higgs couplings in the mass eigenbasis of the randall - sundrum @xcite ( rs ) model with a brane higgs is performed.   the results are compared to the results of a model independent study of the same model in @xxcite and to the bounds on the kaluza - klein ( kk ) mass scale that are required to keep under control the effects of the tree level exchanges of kk gluons on the one hand and of the higgs boson on the other hand. for a light composite higgs that couples strongly to new heavy states   it is shown that the resulting higgs contribution to @xmath0 is well of the order of magnitude larger than the bound deduced in@xcite, at least for a bulk higgs.
bias is a general term used to describe the amplitude of fluctuations inferred from clustering of galaxies with that derived from mass distributions.   it is widely used in the determination of cosmological parameters from samples of redshift surveys of galaxies, but we have really very little idea about which the bias parameter @xmath1 should be. here  , we show that even in linear bias model, the behavior of scale - dependence can not be described by one parameter @Xmath1, but by a series of @x Math4-spectra of wavelet - coefficient - represented bias parameters @x math5 and @x maths6, both of which are positive integers. on the other hand, for galaxies of all types and luminosities,   the scale dependence of the bias index @xMath1 is weak, and some detections give different conclusions. as a result, we propose a new model of bias, which is based on the non - local and/or non - linear relation between the number density of galaxies and the background mass field, and takes into account the rate of star formation.
the hamiltonian formulation of statistical mechanics is a covariant reformulation of the standard statistical mechanics.   the symplectic formulation is used to determine the fundamental canonical poisson brackets and the kinematics for the system under consideration. in this paper  , we show that the symp eclectic formulation can be used to study the hamiltonia of systems with nontrivial topology ( e.g., systems with a totally compact phase space ) which are considered as the classical limit of quantum systems with finite dimensional hilbert space. by means of the deformed liouville volume element,   it is possible to define the dynamical evolution through the microstates of the system in a coordinate - independent manner on the phase space. based on the canonical symplectic structure one can obtain the canonical measure which can be viewed as a mathematical expression for the principle of equal probabilities in standard statistical physics.
the study of the solar neighborhood kinematic groups in the galactic plane has a long tradition in galactic astronomy, going back to the discovery of the hyades and ursa major groups in @xcite.   previous studies have considered models for the non - axisymmetric components of the galaxy motivated by the dynamical point of view, in particular weak spiral arms described by a cosine function and bars described by the quadrupole perturbation. however, it is unclear whether there is any dependence of the induced local solar neighbourhood kinematics on the detailed galactic structure. here   we investigate this question by performing numerical integrations of test particle orbits on the Milky Way using a model that satisfies published observational constraints to the milky way structure, in particularly to the non-axisymmetry components. at the end of the simulation, we consider for the first time initial conditions and integration times that attempt to represent stars born at different times and with different kinematological conditions, like those in the solar region. as a result  , we find that the results of the simulations are not consistent with the observed observations. moreover, the initial conditions hardly consider the evolution of the Milky Way structure.
the nambu - goto model of the qcd string is considered as a generalization of the covariant action for a relativistic point particle moving in space - time.   the interquark potential between two sources i.e., the static potential and the string tension, has been studied by various methods. here   we present the solutions to the gap equations for the lagrange multipliers and metric components of the model and obtain a very simple looking formula for the inter quark potential which is identical to the one obtained by alvarez in the large - d limit. also we provide a discussion of lscher term and argue that it remains universal with no mass contributions coming from the point particles attached to the ends of the string.
entanglement content is one of the fundamental ways to characterize nonlocal quantum resources ( nonlocal states and operations ).   substantial progress has been made recently in investigating ( dis)entangling capacities of unitary operations. however, extending these techniques to systems of higher dimensionality seems to be a very difficult task. even in the two - qubit case the capacities of a general unitary operation have been calculated numerically, but no analytical technique is known. in this article   we consider nonlocal completely positive trace preserving ( cptp ) maps of the form    @xmath0   where @x Math1 are unitary transformations. for some particular cases, we calculate single - shot capacities of @x math2 that act on two qubits. by using the entanglement of formation measure @xcite as a measure of entangler of the initial state, we show that the maximum increase ( decrease ) of the capacities can be achieved when @x maths2 acts on quantum states with the same number of qubits.conclusionsthe results of this article show that it is possible to estimate the single -shot capacities of units in a way that is independent of the operational context.
the formation, acceleration and collimation of extragalactic jets is still an open issue, despite the great amount of information provided by improved vlbi techniques from the ground and now from space, and the detection of jets in the optical and x  ray bands.   we still do not know the amount of power that the jets must carry and their matter content. to estimate the kinetic jet power @xmath0 directly, we use radio data on the milli  arsec scale ( corresponding to a linear scale of the order of a parsec ), taking advantage of the apparent superluminal speeds measured in blazars to estimate their bulk lorentz factor, and then estimate the minimum amount of leptons required to account for the observed emission. using the results obtained from the spectral modeling of the spectral energy distribution ( sed ) of blazar sources binned according to their radio power, we calculate the size, magnetic field, particle density, and bulk Lorentz Factor, necessary to calculate @x math0. within such a scenario,   the model predicts that the emission is due to the synchrotron and inverse compton processes, where the latter one acts on both the syn
the baby - skyrme model of nucleons is a useful laboratory for studying soliton physics.   it is the 2 + 1 dimensional analog of the model which describes the low energy chiral dynamics of qcd@xcite, the usual skyr me model. in this paper   we present an analysis of the skyrmion type solution, including its quantum rotational spectrum taking into account the deformation due to the centripetal acceleration. as a result  , we show that the back reaction of the rotation on the form of the soliton has never been taken into account in obtaining the quantum rotular spectrum.    we can do so because we can analytically solve the full equations of a steadily rotating baby-skyrmions.. afterwards, we continue with our string solutions, already exhibited in our previous letter@xcitesite and present closed string solutions which are physically more realistic. finally, we present some indications on the low energies scattering of baby - Skyrmias.
the spreading of energy in nonlinear hamiltonian oscillator chains with disorder is known as the " absence of diffusion ".   this phenomenon was first studied in numerical experiments using the discrete nonlinear schrdinger equation with local disorder, e.g.  @xcite, later called anderson localization. here  , we want to draw further connection between the microscopic chaos and the diffusion properties in strongly nonlinear systems by analyzing the scaling of the probability of chaos in such systems.    we find that the scaling behavior of chaos depends crucially on the choice of nonlinearity. for a fully nonlinear model where the coupling is strictly nonlinear, the scale of chaos scales significantly around the transition point from chaotic to regular phase space in dependence of the system size. in the case of harmonic oscillators with nonlinear coupling,   the scaling is much slower than for systems with disorder, while for highly nonlinear models the scaling does not depend on the presence of disorder but is rather dependent on the number of interactions between the two oscillators at the center of the hamilton function. by connecting the scaling behaviors of chaos with the phenomenon of chaotic diffusion in these systems   we are able to deduce
the notion of unparticles was recently introduced as an interesting possibility for physics beyond the standard model.   we argue that the sn  1987a energy - loss argument provides very restrictive constraints on the unparticle couplings to nucleons, neutrinos, electrons and muons in a single - particle ( sn ) core.    we find that the dominant lowest - order process for the emission of new particles in a sn core tends to be nucleon bremsstrahlung.. this process involves the small coupling of the new particles to lowest order processes, and it is the only one that can be reasonably estimated at low energies.
rotational reconstruction of sapphire is investigated by means of a simulation of the @xmath15 rotation of the surface.   the results show that the origin of the rotation is caused by strong overlayer  substrate interactions and not by lattice misfit between the al metal overlayer and the substrate, as previously proposed by novaco and mctague for other rotationally reconstructed systems.
the angular einstein ring radius of a microlensing event is directly related to the physical parameters of the lens ( lens parameters ) by @xmath5^{1/2 }, \eqno(1.1)\ ].   the uncertainties in the astrometrically determined values of the angular e Einstein ring radius,@xmath0, depend on the lensing parameters, i.e., the lens - source separation, the impact parameter, the time of maximum amplification, and the einstein timescale. however, due to the degeneracy in the lens parameters, the nature of the Lens population is still very uncertain. here  , we present a new method for measuring the lens proper motion from the measured astrometric shifts of the source star image centroid using the proposed  space interferometry mission _ ( allen, shao, & peterson 1997, hereafter sim ). with this method, we can measure the lens Proper Motion from the measurements of the light centroid shifts caused by gravitational microlensectomy events at high enough positional accuracy to determine the exact size of the ellipse of the effect parameter, which is directly proportional to the spherical shape of the micro
abstractthe kleinmann - low ( kl ) nebula is a source of extended infrared ( ir ) emission that is located northwest of the trapezium stars in the orion nebula cluster @xcite.   the nebula contains a dense group of young stellar objects, some of which appear to have masses of @xmath3 @xmath4, making it the nearest site of massive star formation. for one of these massive stars, the becklin - neugebauer ( bn ) object, the proper motion of bn has been previously measured with multi - epoch radio observations, and it indicates that it may have passed near radio source i in the kl nebula 1500 years ago. here  , we report the discovery of a high proper motion for source x from @xaite. based on its motion,   source x likely originated from the same multiple system that produced bn and source i. meanwhile, we find that the proper motions of source  n are inconsistent with participation in that event.
the ginzburg  landau model of superconductivity is based on the energy functional, which is gauge invariant in the setting of bounded domains.   it is natural to expect that if a superconducting sample is submitted to a uniform magnetic field of strength, then it will be in its normal state for all values of @xmath5, i.e. this result has been proved recently in a number of geometric situations and in both@xmath1 and @x math6 dimensional settings. however, nature does not support this monotonicity in general. in this paper   we show that for narrow cylinders ( or @x Math1d annuli ) one can get an oscillatory behavior instead of monotonity. by using counterexamples in the general case  , we find that the topology / geometry of the annulus is the cause of the oscillatory effect.
the study of complex networks has received an enormous amount of attention from the scientific community in recent years.   one such problem is the analysis of community structure found in many networks. as a result,   the problem of identification of communities has been the focus of many recent efforts. among the algorithms based on network topology, spectral analysis method and gn algorithm   are the most widely used. however, the inherent defects of these methods have not been solved perfectly and completely yet. here  , we review the advantages and disadvantages of random walks method and circuit approach method for detecting communities.
the interaction of a charged particles beam with a plasma is an important subject of relevance for many fields of physics, such as inertial confinement fusion ( icf ) driven by ion or electron beams, high energy density physics, and related astrophysical phenomena.   this interaction is also relevant, among others, for the fast ignition scenario ( fis ) @xcite, where the precompressed deuterium - tritium ( dt ) core of a fusion target is to be ignited by a laser - generated relativistic electron beam. in this paper   we present a study of the effects of intense radiation field ( rf ) on the interaction of projectile particles with an electron plasma. from the theoretical formalism for the electromagnetic response of a plasma due to the motion of a relativistically charged particlesbeam in a plasma in the presence of an intense rf  , we show that the energy loss rate is reduced for ions at intermediate velocities, but is increased for slow ions, due to a resonance process of plasmon excitation in the target assisted by a photon absorption. in the case of a rapid acceleration of the projectile particles in the laser field,   the effect of the rf
summarythe spitzer_/irac shallow cluster survey ( iscs ) is a stellar mass - selected galaxy cluster survey spanning @xmath13.   we report the x - ray detection of two of the most distant iscs clusters : iscs  j1438.1 + 3414  at@xmath25, first reported in @xcite, and iscs j1432.4 + 3250  at @x Math26, for which we present spectroscopic confirmation in this work.    the latter is the most far - away cluster to date to be spectroscopically confirmed in the iscs. using both observations and the sn ia rate from a sample of 25 high redshift clusters collected by the noao deep wide  field survey, we estimate the total mass of these clusters at @Xmath25. 	 the results show that the total masses of these two clusters are significantly larger than previously reported, with the latter being the most massive cluster to have been detected in the current iscs survey.  also, we find that the temperature of the cluster has a significant effect on the observed velocity dispersion between the cluster and its nearest neighbour, as well as on the
the mass of a quark star can be determined from the maximum orbital frequency, @xmath5, on the assumption that this maximum is attained in the marginally stable orbit of general relativity.   we show that the same value of @x math5 can correspond to two stars differing in mass by a factor of a hundred, or more. for maximally rotating models, which are based on the mit - bag model of quark matter, it is crucial to know the rotational period of such stars, if its mass is to be even approximately determined from an orbital frequency.    we find that the orbital frequency of a compact quarkstar can be calculated from the mass of the central object, and that the minimum orbital frequency is obtained from the ratio of the number of up, down, and strange quarks in the star's mass distribution. at low rotation rates,   keplerian orbits graze the stellar surface, but for ~6hz a gap separates stable circular orbits from the stellar surfaces, and the maximum orbiting frequency is reached in the marginally stable orbit ( isco ). for ~1.3 khz qpo frequencies, the isco is found to be the most stable orbit
v405 aur ( rx j0558.0 + 5353 ) is a polarized intermediate polar ( ip ) in the rosat all - sky survey.   the system consists of a spinning magnetic white dwarf ( wd ) accreting matter from a cool low - mass companion, and it has been shown to have the wd spinning down. here   we report extensive multicolour ( @xmath0 ) polarimetric observations of v405 aur, carried out in order to put constraints on the magnetic field strength of the Wd and on the system geometry. using low - resolution circular spectropolarimetry, we show that the spin period of the spinning wd has changed from 4.15 h to 545 s, and that the soft x - ray light curve has a double - peaked structure. by combining these observations with measurements of the polarization flux in the optical and/or near ir spectroscopy, we find that the system has a lower magnetic field than previously known polarized ips, which are generally believed to have lower magnetic fields than polars. for the first time we also find evidence of two - pole accretion of matter from the companion at the opposite magnetic poles of the
sgr1627 - 41 is the fourth soft gamma - ray repeater discovered by the burst and transient source experiment ( batse ) aboard the  advanced satellite for cosmology and astrophysics ( asca ).   it is a neutron star with a magnetic field strength that would make it a magnetar, an object in which magnetic energy dominates all other sources of energy, including rotation. to confirm the periodicity of the source and measure its spindown rate, we observed the source with the asca. using the ximage source detection tool,   a quiescent source was detected at @xmath4 with a 3@xmath5 error radius 55 @x Math6, consistent with the position of the interplanetary network annulus and the galactic supernova remnant ( snr ) g337.0 - 0.1 ; the source displayed a possible periodicity about 6.41 s ( chance probability @x math1, based on a limited number of trials ). to search for periodicity, barycentric light curves were constructed with 0.125 s binning from the sum of the gis2 and gis3 data, by extracting 1 - 10 kev counts from a
we analyse the contribution of bound states to the noise power of a multi - terminal quantum transport system in the landauer - bttiker ( lb ) steady state.   we adopt the field theory framework of @xcite-@xcite, which allows for a systematic account of all bound states. in synthesis  , we show that the current fluctuations at frequency @xmath0 are affected by allbound states with energies @x Math2.    we derive in closed and explicit form both the scattering and bound state contributions @x maths8 and @x math9 to the Noise Power of the system in its lb non - equilibrium steady state from the combined two - point current correlation function and the one - body scattering matrix. using the results of the noise spectroscopy as a starting point, we discuss the general result and illustrate the behavior of the noisy noise power for some values of the parameters characterising the system.
the modulated wideband converter ( mwc ) is a novel analog - to - digital converter that uses compressive sensing to recover sparse signals from far fewer samples.   the quantization reference voltage is an essential parameter to consider about in order to fully use the accuracy of the converter. in this paper  , we theoretically study the reference voltage of quantizer in the m wc. by analyzing the input signal under several assumptions, we draw the conclusion that the reference voltages are proportional to the square root of the collapse parameter @xmath7 and that the conclusion is valid for arbitrary multiband signals.
the magnitude of homogeneous riemannian manifolds is studied using a measure theoretic approach.   the magnitude is calculated explicitly for the @xmath0-sphere of radius with its intrinsic metric, leading to the following answer : r \bigl(\bigl\frac{r}{n-1}\bigr)^2 +   1\bigr))\bigl(r}{ n-3)\bigr ) \dots \ bigl(-r}{2)/i \text{for $ n$ odd } { 1-e^{-\pi r}}\quad &   \text{\for $ o$ odd}. \end{cases} ] for a general homogeneous tautomeric manifold.
active galactic nuclei ( agns ) are usually divided into radio loud ( rl ) and radio quiet ( rq ) objects, and the origin for this dichotomy is still a matter of debate.   the distinction between the rl and rq objects is normally based on a radio - loudness parameter, which is defined as the ratio of the monochromatic flux density at 5  ghz and optical b band at 4400  @xmath1 ( @x math2 ). in the last decade, there is great progress in estimating the super massive black hole ( bh ) mass in both normal galaxies and agns, and it has been found that the bh mass in most llagns is about 1.5 to 2.5 times higher than that in normal galaxies. here  , we review the observations of low - luminosity active galactic nucleus ( llagn ) in the local universe and discuss the implications of these findings.
ldpc codes were introduced by gallager @xcite in anticipation of the ease in their decoding.   the parity check matrix of an ldpc code is sparse and the respective factor graph is locally tree like, which suggests that the belief propagation ( bp ) decoding algorithm, which would decode optimally in a loop free case, should also perform well in the presence of relatively long loops. here   we show that the dendro - code and the original code have identical sets of codewords and pseudo -codewords. for any configuration of the channel output, the results of map decodings are identical for the two codes. using the pseudo - codeword - search method of @xaite, we find the spectrum of the low effective distance pseudo - Codewords for codes which would otherwise be impractical to decode by lp. all together, our simulations suggest that, error - floor performance wise, the analyzed codes are split into roughly two qualitatively different categories : either the error -floor sets in early, at relatively low snr, or otherwise, fer decay, with snr increase, is steeper at moderate snr than at the snr @xmath1 asymptote
in papers @xcite-@xcite an attempt is made to develop an effective field theory formalism suitable for description of hadronic scattering processes.   it was shown that the requirements of consistency of perturbation series for scattering amplitude lead to certain restrictions for the effective hamiltonian parameters that are called _   bootstrap equations. in this talk we discuss the application of our formalism to the case of @xmath2 elastic scattering and show that it is a powerful tool to study the resonance spectrum.
we systematically use the discretized first integral approach to derive non - integrable discrete klein - gordon equations free of the peierls - nabarro barrier ( pnb - free ) from the static solution space of the @xmath0 model @xcite.   the results show that the hamiltonian and non - hamiltonia pnb-free k Klein - gordan lattices support the same one - parameter space of solutions, generalizing the lattices offered in @xaite. for each of these models we describe the full solution space with respect to the underlying static problem, as well as the momentum - conserving model of@xcite, which also includes the solutions derived earlier in @xfite.
total light absorption ( tla ) in lamellar gratings of deeply sub - wavelength thickness is investigated experimentally and theoretically using the emustack package @xcite for numerical simulations.   we show that transverse electrically polarized light, where the e - field is along the grating rulings ( @xmath4-axis ), is totally absorbed in gratings composed of relatively weakly - absorbing semiconductors with a complex refractive index,@xmath5, with surface plasmon polaritons ( spps ) excited by transverse magnetically ( tm ) polarized light ( h - field along @x Math4- axis ), and that this requires metallic materials with @x math7 ( re@x maths8 ), because it relies on the excitation of surface plasmons.
the nordic electricity spot power market ( nord pool spot ) is divided into several price areas, with the system price being a common reference price.   there is a parallel financial market, nasdaq omx commodities, where players in the market can hedge their positions through futures ( days, weeks and months ) and forwards ( months, quarters and years ) against the system Price. however, nobody is exposed to the system spot price, but rather to the area spot price. therefore, the participants can in addition buy cfds ( contracts for difference ) in order to hedge the remaining difference between the system and price area risk. here  , we ask the hypothetical question : what would the cfd market price have been, say in today s no2 ( trondheim at the time ), if it had been traded?   we use bayesian methods to build a model for the expected cfd price even for almost brand new price areas where cfd products are not traded at the exchange. using this model, we find that the expected Cfd price is significantly higher than the observed one for all of the unobserved price areas except for the no1 ( oslo ) area, which is still within the range
the qcd dipole model has been used to describe the deep inelastic electron - proton scattering ( dis ) process initiated by virtual - gluon probes @xcite.   the main process is the onium - onium scattering, that is the reaction between two heavy quark - antiquark states ( onia ) and the proton. within the approach,   a simple analytic expression for the dipole - proion scattering amplitude has been computed taking the scattering amplitude as a solution of the bfkl equation in the vicinity of the saturation line for dipole sizes obeying @xmath11 ( in the photon wavefuntion ) obeying@xmath12 from the qcd color dipole picture. here   we summarize our fit analysis using the q cd dipole phenomenology applied to the dis process @xaite. in what follows, the main expressions are presented and the fitting results are shown and discussed.
one of the basic goals of large scale structure study is to reconstruct the initial mass field of the universe.   assuming observed objects trace the underlying matter field in some way, it should be possible to recover the initial conditions of the mass field from the evolved mass field using a point - to - point, order - preserving transformation. here  , we show that the gaussianization reconstruction of the transmitted flux from the redshift surveys of the galaxy and the ly@xmath0 absorption in qso spectra is still largely non - gaussian even after smoothing the distributions of the two data sets. for the first time, we find that the local and monotonic relation between the original transmitted flux and the evolution of the initial density field is not necessary for a properly gaussianized recovery of the process of cosmic clustering. instead, the transmission of the transmittance from the origin of the dark matter distribution is more likely to be a pixel - to- pixel tracer of the underlying dark matter dynamics.
quantum electrodynamics ( qed ) predicts that vacuum is birefringent in a transverse magnetic field.   the development of ultrahigh - precision technology in the laser - interferometric gravitational - wave detection community prompted our thought of its application to this matter. in this paper, we present the test results of our x - pendulum - double - pendula suspension system, scheme of automatic alignment control and method of improving ellipsometry. in , we also present the magnetic profile of our prototype rotatable permanent magnet and discuss heterodyne detection schemes.
the self  assembly of sub-@xmath0 m colloidal particles at water  air or water  oil interfaces has gained much interest in recent years.   the experimental evidence for this phenomenon is controversial, however, and is based on measurements of the meniscus shape around single glass spheres with radii 200  300 @x math0 m floating at fluid interfaces. here   we present a free energy model for a single colloid trapped at an interface in the limit of small stresses and forces. within the superposition approximation  , we find that the effective potential between two spherical colloids trapped at the interface is determined by the interaction of the colloids with each other via a combination of electrostatic and/or gravitational forces which act on the interface as well as by a restoring force fixed by gravity or electrostatic forces. to investigate the role of the restoring force fixing the interface, we derive a general solution for the interface deformation and show that the resulting effective potential depends on the presence of a stabilizing force at the surface of the trapped colloid.
we propose a model of melting in a two - component alloy based on the physical picture of a material in which the local order is maintained by a strong short - range interaction, so that this local order does not significantly change even when the global order is lost by melting.   the model is written in terms of a local order parameter describing two possible predominant configurations in small elements of the material. to account for the limitations imposed on relative positions of cluster particles by the local Order  , we describe the particle arrangements in terms and orientations of these crystalline arrangements as the fluctuating characteristics of the phase transitions and the phase diagram in this model.the results show that the structure of the alloy is a cluster - scale solution with two types of local order : one with the predominance of one component ( e.g. copper -nickel alloy ), and the other with the dominance of two or more clusters having different predominant components ( i.e. eutectic and monotectic alloys ). under constant pressure conditions, the phases of the materials are characterized by melting, which is a universal phenomenon in all crystalline materials, and by eventual phase transitions due to non - miscibility of components.
the dirac  schwarzschild hamiltonian is a well - known example of the dirac equation for a dirac particle bound to a central coulomb potential.   it is generally assumed that the degeneracy of the space - time curvature corrections to the kinetic term in the Dirac   schwartzschild metric is lifted for gravitational coupling, which implies that the energies of the gravitationally coupled states are not degenerate. here  , we show that this assumption is not the case, and that the energy levels of the energetics of the free dirac hamiltonians are indeed degenerate, but are rather fine - structure constants, which are derived from the gravitational and electrodynamic fine - structures of the bound state. using relativistic quantum mechanics, we identify a set of physical parameters for a gravitationsally coupled system, where the calculations reported here might be phenomenologically relevant. these parameters concern an electron gravitated in a rydberg state, in a black hole of mass, to a mass of mass @xmath21, where @x Math22 is the mass of the earth.
dislocation patterning is a well - known property of crystalline materials that is caused by the motion of a large number of interacting dislocations.   the question how to build up a micron - scale level continuum theory of dislocation dynamics is still an unresolved issue in the theory of crystal plasticity. here   we investigate the evolution of the dislocation correlations on simulated 3d dislocation ensembles in a body - centered - cubic crystal using a density - based continuum model for three dimensions ( 3d ), which is based on nye s dislocation density tensor. as a result   it is found that the correlation properties of the geometrically necessary and induced dislocation densities vary with the size of the external dislocation system. at the same time the spatial distribution of the generated dislocation energies varies with the number of external dis Locomotors. when the two - dimensional ( 2d ) dislocation systems are correlated, the influence of the local dislocation interactions on the geometry of the intermolecular network is more pronounced.    the results show that the observed effects are due to the introduction of new stress terms such as the self - consistent " back
the solar chromosphere and transition region regulate the mass, energy and momentum transfer from the underlying photosphere and convection zones into the upper atmospheric layer, known as the corona.   it is well - known that the complexity of the chromosphere is related to its partially ionized plasma, which does not fulfill local thermodynamical equilibrium. due to chemical reactions such as impact ionization,   the hydrogen gas in the chromospheric layer varies from predominantly neutral to predominantly ionized, which has important consequences on the fluid behavior of the plasma and can significantly affect the magneto - thermodynamics descriptions. here   we have developed two - dimensional two - fluid simulation setups to study the interaction between charged particles and neutrals in a reactive gravitationally stratified collisional media. using the model developed by @xcite, we have studied the effect of partial ionization effects on the propagation and damping of alfvn, fast and slow magnetosonic waves in a chemically reactive multi - fluid system and their interaction with the surrounding plasma. for the first time  , we show that the observed double - peaks in the spectroscopic lines can be explained by the presence of neutrals within the chrom
we have recently shown that black hole space - times with curvature divergences may exist which do not prevent the extension of null, time - like, or space - like geodesics to arbitrarily large values of their affine parameter.   this occurs in a space - time which is essentially coincident with the reissner - nordstrm ( or schwarzschild or minkowski, depending on the choice of parameters ) solution of general relativity everywhere except in a region close to the center, where a wormhole arises giving structure to the standard point - like singularity and connecting two identical copies of this classical geometry. here   we extend this work to investigate if physical observers can safely go through the wormhole, if they undergo some kind of deformation, or simply if they are destroyed in their transit. using a variety of approaches, we find that the wormholes studied in this work are traversable in the sense that geodesic trajectories can go through them. however, given that the components of the riemann tensor, some of which are divergent, are not, it is important to determine if these observers experience any pathological effect as they go through these regions with divergent curv
continuous learning is a method of finding a sequence of improving models for a given fixed data set that we call continuous learning.   the method is based on iterative exploration of a space of models that have a specific limited number of parameters, which correspond to non - linear polynomial features of an input space. in this paper   we propose a new method of continuous learning that consists of a series of iteration cycles where the most important features are selected from the current feature set then the reduced feature set is expanded to include higher degree polynomials while the dimension of the expanded feature space is limited or fixed and the resulting features are computed recursively from iteration to iteration with different parameters of the recursions found for each execution of the iteration algorithm.
ultraluminous x - ray sources ( ulx ) are found in the antennae of @xcite.   we have previously demonstrated that the infrared ( ir ) is a powerful method for finding counterparts to x -ray sources. here, we use x-37 to demonstrate the success of our method and show the importance of obtaining follow - up spectra of counterparts to ulx candidates. using the ir as a go - between to the optical source, we identify a bright, @xmath4 = 16.2 mag source from the x - rays position of x-38, a candidate ulx with a significant offset from a nearby optical source. by using the same basic procedure as used in @xaite  , we also show that it is possible to find similar counterparts to other ulx at the same distance.
the cern collimation system is being upgraded for the second phase of the lhc.   the aim of this work was to investigate the use of an existing analytical model to accurately simulate the impedance of the new phase 2 collimator design. in order to achieve this,   a number of jaw materials were examined and compared over a large frequency range, from 20mhz up to 1.2 million cells ( ~1.5 million cells per cm2 ). as expected, silicon carbide ( sic ) produced a significantly larger real part of the longitudinal impedance that the existing graphite design and the metal / metal - composite designs. at low frequencies ( in the range of khz )   it was found that exposed sic is not a suitable jaw material.
adiabaticity is an interesting concept in physics both for theoretical studies and experimental practices. according to the adiabatic theorem,   if the parameters of the system vary with time much more slowly than the intrinsic motion of the hamiltonian, the system will undergo the adiaabatic evolution.   this condition is usually satisfied at a critical point when the level spacing tends to zero at the critical point. however, a problem may arise when the eigenstates become accident degenerate at some critical points, i.e., when the frequency of the fixed points of the systems becomes zero at these critical points. in this paper  , we present a supplemental condition of the adaabatic evolutionary process for the fixedpoints of classical ham Miltonian systems when the adoabatic condition breaks down at certain critical points in the terms of topology. as an example, we consider a one - freedom classical hamiltonic system with canonically conjugate coordinates. using the nonlinear schrdinger equation, we show that it is possible to find two kinds of trajectories in the phase space for the system : fixed points and closed orbits. by taking into account the fact that the action of
the ads / cft correspondence between the string theories of gravity in the ads space and conformal gauge field theories in the physical space - time provides a completely new set of tools for studying the dynamics of quantum chromodynamics ( qcd ).   one can represent the strong interactions of quarks and gluons by a semi - classical gravity theory i.e., without quantum effects such as particle creation and annihilation in higher dimensions. here  , we study the interaction of the light - front scalar quark - diquark model for the nucleons inspired by soft - wall ads / qcd with the energy momentum tensor in the impact - parameter space to obtain the electromagnetic form factors of the hadrons in the spacetime region of the ad - qcd framework. using the fourier transform of the gravitational form factors obtained from the overlap of the lfwfs in coordinate space,   the charge distributions in the transverse coordinate space are compared in different models of the soft - Wallis - bauer model of ads / Qcd.
disks are expected to form during protostellar collapse, and low - mass stars seem to provide good observational evidence for the existence of disks.   on the other hand, in high - massstars, which form under different conditions with a strong tendency to cluster, the observed evidence for disks is less compelling. here   we utilize the scaling approach for detailed modeling of the spectral properties ( seds ) observed in herbig ae / be stars. using this approach  , we show that the observed seds can be fully reproduced by a simple model based on the behavior of infrared emission from late - type stars at arbitrary scales.
we present and discuss a modification of the fourier modal method ( fmm ) technique for the study of radiative heat transfer between two gold gratings, known as adaptive spatial resolution ( asr ).   this modified method is specifically introduced to accelerate the convergence of the radiation flux between the two gratings. in particular, we extend the fmm technique to deal with arbitrary conical incidence, which has been shown to overcome the known instabilities appearing for metallic gratings   @xcite. using this technique, we show that the temperature - dependent heating of the surface of the gratings can be enhanced by several orders of magnitue, even when the grating parameters are adjusted at the nanometer level. on the other hand,   the effect of the angle of curvature on the energy exchange between the surfaces is not so strong.
we have introduced a formalism to answer some of the questions arising about how best to configure a network of gravitational wave detectors ; in particular, how to optimally site a new detector augmenting an existing network, so as to maximize the detection rate for a standard - candle binary inspiral, and whether the effect is significant enough to warrant consideration in planning the growth of the global network.   the proposed formalism is based on the coincident network analysis technique, which allows independent searches to be performed by each detector in the network ; a signal is only detected by the network when the signal is detected by each member detector. under the assumption that the detectors are identical up to location and orientation ( that is, with identical arm lengths and noise curves ), then a network may be described by the @xmath4 parameters, forming a @x math4 dimensional parameter space.    we have devised a _ figure of merit _, @x Math7, as a measure of the quality of the network. using this figure of merits, we show that the best site to augment an existing interferometer network can be found by fixing the first set of detectors of a@xmath9 detector network, and varying only the latitude and
the current data is consistent with an initial scale invariant and adiabatic spectrum of primordial curvature perturbations which existed outside the horizon at recombination.   these observations are in agreement with the predictions of single field slow - roll inflationary models, but various alternatives scenarios still remain viable. in this work   we use the so called " local model " for the non - gaussianities and specify the amplitude of non - Gaussianity by the parameter @xmath2. in order to estimate the detectability of the various alternatives to single fieldSlow-roll inflation we calculate the deviations from gaussianity of the primordial fluctuations using the cosmological model as a function of the power spectrum of the three - point function in fourier space or bispectrum (  ) and compare them with the results of the cosmic microwave background ( cmb ) polarization experiments that will be performed over a wider range of scales in the next few years.
in their comment, @xcite delaney and greer ( dg ) argue that the unphysical result ( current @xmath2 ) presented by us in ref.   ( hereafter, i ) as evidence against their variational approach@xcite is due to the fact ( i ) that our constraints ( electronic populations ) prevent a broken time - reversal symmetry, and ( ii ) that we used real orbitals, which concomitantly constrain incoming and outgoing electrons. here   we show that this is not true : our constraints _ allow _ a brokenTime-Reversal symmetry, which is the result of the defective variational ansatz ( constrained energy minimization at zero temperature ) of the dg variational Ansatz. using the general response instead of the linear limit of i, we consider now the general many - body state, expanded in terms of the complete set of the real eigenstates of the hamiltonian @x math7 of the finite transport cluster without external bias ( from the previous work ), and consider the general matrix elements of the relevant operators [ external bias Hamiltonian, current operator at site, and current operator with respect to site @x Math13,
the weak coupling expansion of the qcd free energy density does show very bad convergence properties.   the coefficients of the usual perturbation series are of alternating sign and of increasing magnitude only in the tev temperature range can one find a satisfactory numerical convergence rate @xcite. this observation leads us to conjecture that the apparent poor convergence of the perturbatively calculated free energy densities might be improved if the series is reorganised into a loop expansion evaluated with screened propagators ; i.e., instead of expanding around the massless ideal gas limit, we intend to perform the loop expansion starting from a massive ideal gas. for large @xmath0 it also is possible to estimate the 3-loop correction of the free - energy density. finally, we compare the results obtained with this screened perturbative expansion with those obtained from the conventional resummation scheme@xcite as well as from an effective theory approach @xaite.
future particle colliders will explore a new frontier in energy and precision.   final states with more tagged particles and better defined jets will become available for physics analysis. since the primary objective of the next generation of colliders is the determination of the nature of electroweak symmetry breaking, particular care must be taken to obtain gauge invariant predictions. at acat2002,   the @xcite group reported progress on the @xmath2/@xmath3 couplings, @x math4 scattering and @x Math5 production processes.
we present a homology theory for fatgraphs and their polynomials.   we construct a bigraded chain complex using the set of spanning subfatgraphs of a fatgraph and show that the graded euler characteristic of the homology of this complex is the same as the jones polynomial of an associated fatgraph. in this way, we obtain a homological generalization of m.  khovanov s homology group for knots which is equivalent to the j Jones polynoma of a link.    we also show that when the fatgraph is embedded in a plane graph, then the jJones polynometric of the chain complex can be obtained as an evaluation of the tutte polynomic of an edge - signed plane graph ( or equivalently the @xmath1 potts partition function of a plane graphs ).  one of the desirable properties of such a graph homology is that it can be used to construct a homologous knot homology.
the presence of dust in galaxies limits our ability to interpret the local and distant universe, because dust extinction dims and redden the galaxy light in the traditional uv  to  near - ir windows, where the vast majority of the data have been obtained.   this can affect the interpretation of galaxies seds in terms of their fundamental parameters, such as age, stellar population mix, star formation rates ( sfrs ), and stellar initial mass function ( imf ). here   we review the current state of knowledge about the evolution of the dust content of galaxies in the nearby universe and its relationship to redshift.
derived equivalences between finite dimensional algebras are known to be fundamental in representation theory and applications.   unfortunately, still very few positive results are known about the structure of derived equivalences and about homological invariants. here  , we present a proof of the existence of a derived equivalence between two self - injective algeses @xmath0 and@xmath3, which is based on the assumption that both al geometries have faithful strongly projective - injectic modules and that they share homology invariants such as global or dominant dimension. for most known classes of derived equivalent,   the results are negative ; however, for some classes of algebrae, such as those of gendo - symmetric centraliser subalgebra, it is possible to obtain positive results. under some mild assumption, derived equivalencies between self - injecting algebridges @x maths0 and @x math3 induce stable equivalences of morita type and thus there are equalities between global and also between dominant dimensions of @x Math0 and #3.    the key concept to address both questions and to identify suitable and interesting classes of Algebraic Lie Al
the spin transport in the lateral spin valves with ferromagnetic ( fm ) and nonmagnetic ( nm ) electrodes is studied by measuring the spin - dependent nonlocal voltage drop.   the spin injection and detection experiments in the two - terminal geometry are obscured by other effects like anisotropic magnetoresistance, hall effect, etc. to overcome this problem,   experimental groups have adopted the nonlocal spin valve geometry @xcite. in this model geometry, the spin polarized current flows from the left of n ( base electrode ) into f1. that is, spin polarized electrons are injected from f1 into base electrode n and are drained into the left or right of n. the spin injecting electrode f1 is called the spin-injecting probe, while f@xmath0 with @xmath1 will be called the non local ( voltage ) probe. in addition to charge current in the left end of n, diffusion of injected spins generates spin current flowing to left and right ofn symmetrically.    pure spin current to the right of N was detected @xcites with another fm electrode by measuring a spin - independent nonlocal voltammetry drop. on the other hand,
the failure of disk galaxy rotation curves to decline significantly at large radii is usually interpreted as evidence that the luminous disk is embedded within a more extensive halo of dark matter ( dm ).   we show that this is not the case, and that the observed rotation curve does not reflect the true nature of the dm contribution to the central attraction. in order to explain this discrepancy, we introduce a new argument : a rapidly rotating bar within a massive halo must lose angular momentum to the halo through dynamical friction.
we present a large and homogeneous x - ray selected sample of active galactic nuclei ( agn ) from the rosat all sky survey ( rass ).   the sample consists of 40 known emission line agn that have been identified by cross - referencing the rass bright source catalog with the simbad, ned and agn catalogs. in order to keep consistent emission line properties measurements, new optical spectra have been acquired for the 40 additional sources. using these data, combined with the previous optical identifications, we provide a large, bright and ( @xmath6 ) limited sample of emission line Agn in the ro satan x - rays band. here   we show that the main optical counterparts of the sample are @xmath1 line strengths, velocity width of h@x Math0 and the slope of soft x -ray continuum.    we also show that there are several correlations between these properties and x - Ray properties, including the strong correlations between optical fe  ii, @x math1 line strength, [ f   ii]@X   x   y line strengths and the velocity width at 1.
the problem of constructing fast algorithms for multivariate approximation of scattered data points has recently interested many researchers, who work in various areas of applied mathematics and scientific computing such as interpolation, approximation theory, neural networks, computer aided geometric design ( cagd ) and machine learning.   the problem of efficiently approximating many thousands or millions of three dimensional data does not seem to be much considered in the literature, with the exception of a few cases such as in @xcite, where an efficient algorithm with a new cell - based searching procedure is presented for bivariate interpolation of large scattered data sets. in this paper   we directly extend it to trivariate case, obtaining in this way a new fast algorithm for interpolation using the partition of unity method, which involves the use of radial basis functions ( rbfs ) as local approximants and of locally supported weight functions. by using a nearest neighbor searching procedure  , we show that the cube - partition algorithm is efficiently implemented and optimized by applying the partitions of the domain into cubes, which are then used to localize the subset of nodes belonging to each subdomain, thus allowing us to pass from unordered to ordered data structures. moreover, the
the present paper describes the application of collisional - radiative modelling to the description of dynamic finite density plasmas.   it is shown that consideration of relaxation time - scales, metastable states, secondary collisions and other aspects of the competition between radiative and collisional processes in a plasma allows an atomic description of the dynamics of the various populations of atoms and ions in a hot tenuous plasma which are not influenced by external radiation fields. for light elements,   the paper provides an overview of key methods used to expedite this process and draws illustrative results from the ions of carbon, oxygen and neon.
we study the stability of the absorbing phase ( vacuum ) in the @xmath0-species baw@xmath7 models with and without interspecies hard core ( hc ) interaction in a strong coupling regime.   we find that the vacuum is stable for any branching rate and the directed percolation ( dp ) type phase transition is observed regardless of the presence of hc interaction, even in the absence of a spontaneous annihilation process. as the branching rate increases, the vacuum becomes more unstable in the coupled systems, because the annihilation process of only the same species of particles is allowed. furthermore, a sufficiently strong interspecies coupling may wash away completely the absorption phase for large enough @x Math0 even in one dimension, even without any hc interactions.
we present a new method for classifying the supersymmetric black objects in asymptotically flat spacetimes in the five - dimensional minimal ungauged supergravity.   we use bilinears built out of the killing spinor to define a previledged @xmath9-structures, which tightly constrain the possible forms of the metric and the gauge fields. using this method, we have obtained exact solutions to the vacuum einstein s equations in the four dimensions of the hyper - khler base space and the singularities of the black objects are well defined. by using the same methodology, we also show that the quantum theory of supersymmetry can be applied to the construction of black holes in higher dimensions.
multicasting is an efficient way to deliver widely popular content requests from a transmitter to multiple users concurrently in wireless networks.   however, existing works on multicasting have assumed that all the content requests arrive synchronously to the same cell and focus on the analysis of multicasting gains under this assumption @xcite. in this paper, we propose a novel temporal - spatial aggregation - based multicasting scheme to enhance multicasting opportunities for content - centric applications with asynchronous and spatially distributed content requests for elastic services in a large - scale cache - enabled wireless network. by carefully handling different types of interferers and adopting appropriate approximations, we derive a tractable expression for the successful transmission probability in the general region, utilizing tools from stochastic geometry. using asymptotic approximation,   we derive closed form successful transmission probabilities in the large delay region as well as the large and small user density regions, respectively.the results reveal that the success rates of successful transmission increase and the energy consumption decreases at the cost of delay increase in the high - user density region.
55 cancri (= hd  75732 ) is a late g / early k dwarf / subgiant currently known to host five extrasolar planets with periods between around 0.7 days and 14 years and minimum masses between 0.026 and 3.84.   the super - earth 55  cnc e was recently discovered to transit, prompting a number of studies of the properties of this system. here   we report the results of a direct measurement of the stellar angular diameter and calculation of the physical radius of the transiting planet using the chara interferometric array and hipparcos parallax measurement and bolometric flux based on spectral templates and literature broad - band photometry. in particular, we focus on the location and extent of the circumstellar habitable zone ( hz ), based on the equations of jones & sleep ( 2010 ), and our calculated stellar radius value, which is based on simply the measured flux decrement during transit and our calculations of the star's radius.
the 7c redshift survey ( 7crs ) is a collection of spectroscopic data on the radio galaxies in the 7c i and 7c ii regions of the sky.   we have identified all radio sources in 0.1 sr of sky with 151 mhz flux - density @xmath4 jy in the 6ce sample, which contains sources with luminosities approximately a factor of 6 lower than the 3c ( 3crr ) sample at any redshift. to obtain identifications and redshifts for radio sources from this sample, we have used the same method as previously used for the @x math5-band sample, but using a completely identified low - frequency sample fainter than the6ce sample. by combining the results of these two studies   it has been shown that the redshift distribution of the samples is very different. among the seven sources without redshifting from optical spectroscopy ( most of which have very red optical to near - ir colours )   there are only two sources with a redshift of 2.7 jy and one with aRedshift of 1.2 jy ; both of which are found to be quasars.
the study of entanglement in dirac fields in the relativistic framework is important not only from quantum information perspective but also to understand deeply the black hole thermodynamics.   we have investigated the effect of decoherence on the entropy of dirac field by comparing the single qubit and the both qubits decohering situations under the action of bit flip channel and phase damping channel. it becomes obvious that the entangler loss is rapid when both the qubits are coupled to a noisy environment, irrespective of the acceleration. for depolarizing channel  , however, this is not true.
the applied probability field is a broad - ranging one, with applications in a number of different disciplines.   the article describes some basic models, gives pointers to the existing literature and presents a few open problems suggested by our setting. for each of these problems,   we present a brief overview of the current state of the art in the field, and suggest some possible future directions.
the volatile component of the comet c/1999 s4 ( comet linear ) was observed by millimeter - interferometry at hat creek and owens valley in california during the summer of 2000.   we present a weak detection of hydrogen peroxide ( hcn ) in auto - correlation mode and upper limits on the emission in crosscorrelation mode, and place limits on spatial extent of the emission using models of hcn excitation in comets from @xcite.
multiwavelegth ( mw ) observations are important for the glast observatory @xcite.   particular motivations for such studies with the gamma - ray telescope ( lat ) include :   source identification and population studies.the glast lat multiwavelength coordination group ( glamcog ) has been formed to prioritize science - driven needs and develop an implementation plan for cooperative multiwa wavelength observations before and during theglast mission. based on current knowledge of the Gamma - ray sky, many glast Lat studies will require mw cooperation for the maximum scientific return.    four of these are described here.
the lpm - effect in bremsstrahlung is a well - known consequence of interference effects in the gamma - quantum emission from ultrarelativistic electrons passing through an amorphous scattering medium.   it has been studied for finite - thickness targets, and for the opposite limit of thin target, which is of intrinsic interest @xcite, and the theoretical predictions were accurately tested experimentally only within the last two decades. here  , we review the state of the art in the field, and discuss the recent experimental verification of the existence of this effect on compound targets.
the cosmological horizon problem is one of the most intriguing problems in cosmology.   why is the universe so homogeneous and isotropic on large scales?   how were the opposite sides of the universe able to coordinate so precisely? here  , we review the evidence for the existence of high - order anisotropies in the cosmic microwave background ( cmb ), which have been detected by experiments before cobe, by cobe itself, and by subsequent experiments, and this is set to grow dramatically with future experiments culminating in the map and planck surveyer satellites. using these data, we show that the cmb is very close to black - body, which imposes important constraints on entropy deposition, late particle decays, reionization, etc. at the same time, the universe is highly isotropy, providing the best evidence yet for the relevance of a friedman - robertson - walker cosmologic model of inflation as the driving force behind the observed cmb anisotropy. during inflation,   the field energy density of the cosmos would have been dominated by a constant term, which would have generated an epoch of exponential growth of the scale factor,
the behavior of small particles immersed in a shear flow has been of interest for a long time.   the motion of the particles is quasi - periodic, with a stochastically distributed period. in this paper   we revisit the problem that burgers discussed and extend the solution to arbitrary values of the weissenberg number @xmath0 by numerical exact methods. in particular we are interested in the large-@x Math0 limit, which allows us to derive the flow pattern in orientation space, to extract the periodicity and to give the average tumbling time.
the discovery of a primordial magnetic field ( pmf ) would have a profound impact on our understanding of the early universe and would help explain the origin of the observed magnetic fields in galaxies and clusters @xcite.   the cosmic microwave background ( cmb ) is a promising tool to discover and study the pmf on the largest cosmic scales. here  , we investigate the contribution of the galactic rotation measure ( rm ) to the total faraday rotation ( fr ) signal from the cmb using the lyman-@xmath0 forest spectra of @xaicite. by fitting the rm data from extragalactic sources to the scale - invariant power spectrum of @xmath6, we find that the galaxy has a typical galactic rm of about @x Math6 ng, which corresponds to an effective pmf strength of ~1.5 ng for the weak lensing b - mode. with the next generation cmb experiments operating at lower frequencies and combining fr information from several channels, we can further improve the constraints on the size of the galaxy's pmf by an order of magnitude.
the heisenberg model@xcite expresses the energy dependence of localized electron spins by means of the exchange interaction.   this assumption creates a starting point for an analysis on magnetic states in insulators, but the exact solution of the model is often difficult to find. here  , i introduce a new model that remains with the essential features of the hubbard model, but simplifies it using a classical situation for the hopping. despite the simplification,   the model must be capable of describing the magnetism of materials with itinerant electrons.
the problem of reconstructing binary matrices from their row and column sums is a classical inverse task in combinatorics.   we address the question of consistency of the data by adding additional window constraints, specifying ( or giving bounds on ) how many points there are in certain minors of the matrix, which come up naturally in _ dynamic discrete tomography _ ( @xcite ). as it will turn out, the problem exhibits various unexpected complexity jumps when adding different kinds of window constraints. here   these jumps are explained by taking a complexity theoretical view commemorating two well - known observations : ( 1 ) the question whether there exists a matrix whose row and columns coincide with the given data and ( 2 ) whether the underlying matrix can be solved in polynomial time.
abstractthe far - infrared ( far - ir ) spectroscopic capability of the japanese infrared astronomical satellite, akari @xcite, which was launched on february 21, 2006 ( ut ), is realized by a fourier transform spectrometer ( fts ) as a function of thefar - infrared surveyor ( fis ) @xcites.   the far -ir spectrum of   88,  ] in the large magellanic cloud ( lmc ) in the 30 doradus region ( @xmath17 ) of the akari@xcite satellite was obtained with a single beam of 80@x Math17 in fwhm using the fis - fts detector arrays of the kuiper airborne observatory ( kao ) and the koei / ctio magellanus cloud emission line survey ( mcels ) instrument of the international space observatory for the infrared ( icac ) at the university of michigan/ctio ). to obtain the far-ir spectrum, the iso /
magneto - optic imaging of single vortices in superconducting and soft magnetic films has been a long standing goal.   the first experimental results have already been obtained using bismuth - substituted ferrite garnet films with in - plane magnetization and low domain activity, but to date no theory exists which can explain the interactions between these two types of films. here   we take the first step towards a theory which explains this interaction by considering the case of a thin superconductor with a diameter of infinite extent and a thickness of much smaller than the penetration depth of the supercond conductor. as a result  , we assume that the magnetic film is made up of surface charges separated from thesuperconductor by a very thin oxide layer ( of thickness t ), and that all the polarization rotation takes place within the first few nanometers of the film. for this purpose, we argue that the kerr effect applies to thin films, where all the polarizations are induced by a vortex located at z=0, and the magnetically induced currents are generated in the same plane as the vortex.we present a theoretical model for the interaction between superconductors and hard magnetic films based on the k
the spectral representation of the effective dielectric constant of a two - phase composite material @xcite is proposed for analyzing the electrorotation of particles in suspensions.   the spectral representation is a rigorous mathematical formalism that allows the separation of material parameters from the cell structure information, thus simplifying the study. from the spectra of the dispersion spectrum, one can easily derive the characteristic frequency as well as the distinctive frequency dependence of the polarization response, with the latter being explicitly expressed in terms of the structure parameters and the materials parameters of the cell suspension. to our knowledge, none of these methods have been used to separate microstructure parameters from material information. in this work, we propose the use of the spectral representations of the complex effective Dielectric constants and the volume fraction of inclusions of the suspended cells to study the influence of the nanometer - scale microstructural parameters on the electrophoresis behavior of cell suspensions.
we demonstrate that the orbital effect, which so far has been regarded as detrimental to the fermi surface splitting in the applied in - plane magnetic field, can in fact induce the nonzero - momentum paired state in a metallic cylindrical nanowire.   this situation is facilitated in a unique manner by the transfer of kinetic energy from the rotational to the translational degrees of freedom of the ferrell@xcite ( ff ) quasiparticle states in the wire with nontrivial azimutal states ( i.e., in the direction perpendicular to its length ) within a modified bardeen - cooper - schriffer ( bcs ) approach, in which the superconducting gap acquires an explicit angular momentum dependence and the self - consistent equation for the gap is explicitly specified. we also provide an argument for the feasibility of such state observability.
the classical - field treatment of the bose gas is appropriate to describe the dynamics of condensate formation.   this chapter describes methodologies in which an equation of motion for a classical field provides a beyond - mean - field description of the degenerate bose gases. using the stochastic projected gross  pitaevskii equation ( spgpe ) formalism, we show that the equilibrium correlations between the low - energy, highly - occupied modes of a bose einstein condensates ( bec ) and a bath of high - energy atoms are well - described by a classical wave equation, and that the non - equilibrium dynamics of the finite - temperature bosegas can be simulated using methods based on the gpe. while these methods neglect the effects of quantum fluctuations, they have the significant advantage that they treat the classical fluctuations of the field non - perturbatively, and hence can be applied in the critical regime around the bosing - condensation phase transition.
the thermal emission from the surface of a neutron star traces the star s cooling history.   it is expected that the presence of an atmosphere on the neutron star surface will distort the emerging radiation by altering the blackbody energy distribution and introducing absorption features. here   we report on an observation of the radio - quiet neutron star , which was detected by the european photon imaging camera ( epic ) instrument in december 2001 at 19:13 ut and lasted for 28.4 ks. using data obtained with the epic instrument, we show that the pulsar has broad absorption features at @xmath00.7 and @x Math01.4 kev in the spectrum of its soft x  ray emission. to our knowledge, this is the first time that these features have been observed in the same region of the spectrum as predicted by atmospheric models.
a new atmospheric cerenkov array to study cosmic sources of very high energy ( vhe ) @xmath2 rays has been set up in pachmarhi in central india.   the array consists of 25 telescopes deployed in a field of 80 m@xmath3 100 m area and consists of 7 parabolic mirrors, each of diameter 0.9 m. the arrival time of the cerenov photons from the array has been calculated using the tdc information from the so called'royal sum'pulses and individual mirror outputs for the crab nebula and several background regions with the same declination as crab. among the various methods used for the estimation of the arrival direction, the monte carlo method has been found to be the best suited.
we investigate the performance of a mac - phy cross - layer technique for collaborative beamforming in a wireless network under imperfect conditions, i.e., when there are channel estimation errors and phase errors.   we assume that the network is divided into clusters, so that nodes in a cluster can hear each other s transmissions. during slot @xmath0,   source nodes tend to communicate with nodes in cluster@xmath2 that belong to clusters @x Math3 and @x maths4, respectively.    the collaborating nodes are assumed to be uniformly distributed over a disk of radius. 	 we model the network as a slotted packet system, in which each packet requires one slot for its transmission. using knowledge of network coordinates, each collaborating node adjusts its initial phase so that the resulting beampattern focuses in the direction of the desired destination. by applying this approach, we find that the complex baseband - equivalent channel gain between nodes in the same cluster is much greater than the maximum distance between source and collaborating nodes ( p < 0.05 ).  also, the time required for beamforming is significantly reduced compared to the current state - of - the - art approach.
the geodynamo is the process by which the rotating, convecting, electrically conducting molten iron in the earth s fluid core maintains the geomagnetic field against ohmic decay.   the full dynamo problem requires the examination of the full three dimensional partial differential equations governing convective, incompressible magnetohydrodyamics ( mhd ). in the past decades   computer models have been used to simulate the actual geodynamic process. however, as glatzmaier et al   @xcite remark, no three dimensional dynamo model has been run at the spatial resolution required to simulations the broad spectrum of turbulence which surely exists in the human fluid core. here   we present a simplified version of the mhd equations for the evolution of the velocity vector, the magnetic field vector, and the buoyancy field in the boussinesq approximation and written in the frame of reference rotating with angular velocity. following the notation of moffatt and loper  , we write the equations in terms of dimensionless variables that are motivated by the physical postulates of the magnetogeostrophic equation proposed by moff att and j. loper.    the results show that the
we try here to work out a simple case of equatorial circular particle orbits around a rapidly rotating black hole to show how to treat this problem perturbatively in the time domain.   we use the latest version of a code originally developed by laguna and collaborators @xcite to evolve the teukolsky equation from a generic initial data slice to a more complex one that includes the self - force of the radiation reaction forces along the past light cone of the particle. for the first few @xmath0 multipoles of the spheroidal harmonics expansion,   the proposed fully relativistic radiation reaction schemes are used to calculate the waveforms and energy fluxes of the gravitational waves emitted by a particle in a bound orbit around the black hole. using the new code, we find that the rate of the decay of the object making the orbit decay in time is proportional to the number of modes of the spacetime - dependent interaction between the particles in the orbit and the black holes at the time of the collision. when the object is not in an equatorial orbit, the decay takes place in a non - equatorial plane, and the effects of the spin of the particles on the space - time decay
water melon diagrams are a class of multiloop sunset - type feynman diagrams in perturbation theory.   the most important application of these diagrams is the calculation of the effective potential in quantum field theory both at finite temperature and at zero temperature. among other applications   one can name the sum rule analysis of baryons in qcd both in the massless approximation and with finite mass ( the leading order correlator being the standard sunset diagram ) or the treatment of beryons in the large @xmath4 limit of qcd which requires the calculations of @x math5-loop water melon diels - alder diagrams in the Leading Order.    in this paper we discuss a method to calculate the near threshold expansion of the spectral density for the class of multi - loop sunset -type feyn mann - whitney diagrams termed water melone diagrams  . the method is simple and reduces the calculated integral to a one - dimensional integral which includes only well - known special functions in the integrand ( bessel functions of different kinds ) for any values of the internal masses. as a consequence  , it is possible to obtain an analytical expansion that can be used for the simpl
we study the dirac equation for a fermion coupled via yukawa interaction to a system of two colliding domain walls in five - dimensional minkowski spacetime.   we find that the initial fermions exist on both branes, and that without exception, for a whole range of initial conditions, the two initially distinct but localized fermionic distributions merge in the neighborhood of the collision, and then emerge after the collision again localized on one or the other kink. by contrast if one of the kinks is empty, which we refer to as a vacuum brane, then the amplitudes of the fermium zero modes associated with it highly depend on the incident velocity and the coupling constants.
recent hst data have revealed the presence of prominent compact nuclear sources in many spiral galaxies of all hubble types.   the processes that lead to the formation of such clusters in the very center of galaxies are not well understood, and many questions remain to be answered : is the cluster formation process self - regulating in the sense all clusters form over similar timescales?   how stable are nuclear clusters? is a stellar bar required to funnel gas into the central regions of galaxies? as a consequence,   repetitive cluster formation is thought to be necessary for galaxy bulge formation. here  , i describe a program to obtain high - quality spectra of the nuclear clusters of a sample of late - type, face - on spirals for which the cluster can be separated from the galaxy disk in ground - based observations. using the mass - to - light ratio  of a stellar cluster as a sensitive age indicator, we derive the cluster ages from the observations and give an example for the successful application in sec.   .
we investigate the azimuthal decorrelations in mueller  navelet jets using the balistky  fadin  kuraev   lipatov ( bfkl ) equation  @xcite beyond the leading order approximation initiated in ref.   we investigate the inclusive hadroproduction of a pair of jets with large and similar transverse momenta produced at a large relative rapidity separation y @xcite. to a good accuracy  , we argue that the particular choice of rapidity variable removes the dependence on the parton distribution functions in normalized cross sections. for different conformal spins we study the structure of the scale invariant next  to  leading ( nlo ) bf Kl kernel which is based on the sum of the angular averaged case and the asymptotic intercept corresponding to the linear averaged case. by resummating the nlo bfkr kernel to all orders we show how the convergence of this kernel is poor for zero conformal spin while it is much better for larger ones. from the theoretical side   our results provide too much decorrelation when they are compared to the experimental measurements. however, this could be due to the approximations needed to obtain
we introduce a metric where its curvature singularities are, exactly, located at the phase transition points.   this effective metric has different structure from the other known metrics which are defined as the negative hessian of entropy with respect to the internal energy and other extensive quantities of a thermodynamical system @xcite. in this paper, we consider the black hole solutions with born - infeld ( bi ) and maxwell ( maxwell ) sources in three and four dimensions and investigate phase transitions in various geometrothermodynamical methods. for this claim, we firstly consider the heat capacity of ads black holes in the context of canonical ensemble and then we solve the problem of phase transition in terms of the legendre invariant metric where the curvaturesingities of the metric are, exactly, situated at the phases. finally, we investigate the effectiveness of the new metric by considering the blackhole solutions with bi and max well sources in two and three dimensions.
the cubatic phase of cut - spheres is a long - range orientationally ordered phase without any positional order of the particles.   we investigate the existence of this phase by computer simulations of a system of freely rotating cylinders, which are obtained by symmetrical slicing off the polar caps of a sphere. as a function of the length over diameter ratio of these particles,   they connect the infinitely thin discs with the spheres. in the absence of translational order  , the particles tend to form stacks of several particles in an approximately cylindrical shape. after aligning the particles, the system can easily be compressed, nevertheless, the nematic to columnar transition for this system has been studied using the onsager model @xcite. in this article   it is shown that the system exhibits a coexistence between the isotropic liquid and the crystalline phase, even though there is no attractive interaction between the two phases.
in order to detect a quark - gluon plasma ( qgp ) possibly produced in ultrarelativistic heavy ion collisions, we are dependent on a thorough understanding of the properties of a qgp and a prediction of signatures for the qgp formation.   we are forced to use quantum perturbation theory ( qcd ) at finite temperature and chemical potential, since the q gp is a relativistic quantum system of partons at infinite temperature and baryon density.. the second approach is perturbative qcd at finite temperatures, which is based on the fact that due to asymptotic freedom the effective temperature dependent strong coupling constant ( @xmath0 ) becomes small at high temperatures. here   it is shown that this method can be applied to the calculation of static as well as dynamical quantities of a Qgp. also it is straightforward to extend this method to finite quark chemical potentials. furthermore the application of perturbational qcd to non - equilibrium situations, expected to take place in the first stage of a relativation of the first step of a relativity - mediated heavy ion collision, is possible and the topic of current investigations.
the deconfinement transition from hadronic to quark matter in protoneutron star ( pns ) conditions is studied using a nonlinear walecka model employing the mit bag model.   the effect of different parametrizations of the hadronic equation of state and different neutrino trapping conditions on the transition density at finite temperature is investigated. for the just deconfined quarks we employ the nambu - jona - lasinio ( njl ) model for the interaction of hadrons, electrons, and electron neutrinos in equilibrium under weak interactions with leptons. for both hadronic and quark phase we use color superconductivity as a proxy for flavor conservation. by comparing the results of previous calculations using the njl model in the description of quark subject to different parameters of the equations of state, we show that the effects of color superconduction and neutrine trapping are not sufficient to prevent the transition from having a hadronic phase to having a quark one.
we present a new polar coding scheme for the general wiretap channel using two recently developed techniques for polar codes.   the first is universal polar coding, which allows us to align the good sub - channels of the main and eavesdropper channels together. in the second is polar coding for asymmetric models @xcite, which enables us to deal with the non - uniform input distribution. by applying these two techniques, we can achieve the secrecy capacity of the general Wiretap channel.
we investigate the singlet - triplet ( st ) relaxation induced by the confined phonons in self - assembled two - electron quantum dots ( qds ) embedded in inas nanowires.   we find that the st relaxation is much lower at the vicinity of the st anti - crossing due to the mismatch of the phonon emission wave length to the dot size, which leads to the strong st mixing between the triplet state and the ground state. as the nanowire - based qds are perpendicular to the substrate, the bulk phonons from the substrate are less important than the confinement of the electrons in the nanostructured qd.
in the framework of geometrical engineering, gauge theory at low energy arises from co - dimension four singular surfaces in the compactification manifold @xcite and charged matter arises as isolated points ( curves in f - theory ) on these surfaces.   the description of the geometry of the singularities themselves was taken for granted, but recent successes in m - theory model building motivate a new look at how to describe the relative structure of singularities  at least locally  within this framework. in this paper   we show that the number, type, and relative locations of the individual singularities required by low - energy phenomenology can be reduced by deforming a smaller number of them in a more unified model. using the same framework as described in@xcite, we derive a new way of relating manifolds with matter singularities to those with more or less symmetry via a novel way of model building.. the idea is used explicitly to deform an @xmath0 grand unified model into a standard model.
the metric space technique ( mst ) is a tool used to analyze and classify astrophysical maps.   the mst allows an objective and quantitative comparison of any two images, where, instead of comparing images on a pixel - to - pixel basis, the comparison is made by considering the metric distance between two images output functions. here   we use the multi - scale mst to quantify morphological differences between the sloan digital sky survey ( sdss ) observational data and two sets of simulation sample data and then illustrate the use of those differences to understand degrees and types of structure in the galaxy distribution. using this novel approach, the Mst not only informs us, quantitatively, about the structure information of the universe and which mock sample most resembles the observational data, but also how the information and resemblance vary over size scales.
microcavity polaritons are the quasiparticles that result from strong coupling between photons confined in planar semiconductor microcavities and excitons confined in quantum wells.   they are hybrid light  matter particles, which have both a light effective mass, as well as sufficient interactions to allow a quasi - equilibrium particle distribution to be established. due to the weak attractive interaction between opposite spin polarizations, a condensate is expected to be linearly polarized@xcite, i.e., to have an equal density of left- and right - circularly polarized components. applying a magnetic field   can then lead to a phase transition, as the density of one circular polarization increases, and the other decreases, leading through an elliptically polarized phase to a single circularally polarized condensates. here  , we investigate the rich varieties of behavior that come from combining spatial profiles driven by particle flow with the dynamics due to their spin degree of freedom : the observed spontaneous vortices in polaritoncondensates provide a strong hint that the steady states of the system are affected by the flow of particles.
the h1-plug - calorimeter is the first hadronic silicon instrumented sampling calorimetry, which has been operational since 92 within the environment of the hera electron proton collider at cern.   it is designed to fill the gap between the forward part of the lar calorimeters and the beam pipe and thus to ensure the hermeticity of the energy measurement @xcite. in recent applications   the plug has proved to play an important role for the tagging of rapidity gap events@xcite.severe radiation damage of the silicon detectors used has been observed in particular during the 94th run period after a strong increase of the delivered luminosity. here   we present the results of the monitoring of the diode characteristics during the operation of the plug subdetector of h1 and compare them with the final analysis of related measurements as performed in the laboratory.
we study a method to generate entangled microwave photon states in two separated cavities coupled by a superconducting qubit using multiphoton transitions.   we first show that the longitudinal couplings can induce two - mode multipoton processes similar to those in trapped ions, and then study an efficient way to generate superposed two - modes photon states. for the first step,   an effective hamiltonian, similar to that of trapped ions with two vibrational modes, is derived from the interaction between the cavity field and the two - level atom ; then different sideband transitions are discussed. for second step, a new algorithm is introduced to generate arbitrary superpositions of two-mode photon states based on the inter - mode interactions between the quantum qubit and the cavity fields of two modes. finally, we numerically study the effects of both imperfect control pulses and the environment on the generated target state.
the formation of quark stars is a well - known mechanism for the formation of neutron stars.   it has been proposed that quark matter can be used as a source of radiation emission for cosmological x - ray bursts, and that some neutron stars can undergo a phase transition to become strange stars at high densities and/or temperatures. in this paper   we review the properties of strange stars based on the so - called mit bag model, which assumes that quarks are confined to the qcd vacuum inside hadrons and that they interact with gluons by means of strong interaction. using numerical methods we have studied the linear approximation of the equation of state of strange matter, where the energy density of the quark - gluon plasma is the difference between the perturbative and non -perturbative qcduum ( the bag constant ), and the equilibrium photon emissivity of the strange matter is the product of the baryon number density and the chemical potential of the Quark - Gluon interactions.. the results show that the solution of the eos of the gas of massless particles is well approximated by a polynomial function of the quantum chromodynamics equation
the lupus star forming region, recently reviewed by @xcite, lies about 150  pc from the earth in the gould belt.   it is immediately visible by inspection of optical photographs of the sky, comprising a set of largely filamentary dark clouds. using the ` cores to disks'spitzer legacy programme ( c2d, *???   * ; *????* ; *???'?,@xmath0co  21 and co 43 maps presented here are the first large - scale fully sampled low-@x Math7 co maps of lupu, and the first mid-@Xmath7 co Maps of any kind.. the molecular hydrogen in the lupi complex is clearly delineated by the rotational emission of carbon monoxide ( co ) and isotopically substituted carbon monoxides. at low latitudes ( @xmath8 ), a large mass of diffuse gas contains denser filamentary clouds ; at higher latitudes, the density of the clouds is more clearly separated.
the nonlinear optical response of semiconductors is an important problem of modern condensed matter physics, in particular due to the necessity to describe correctly the ultrafast laser pulse experiments @xcite, including the four - wave mixing ( fwm ) case.   this problem is a part of a more general problem of the nonequilibrium nonlinear behavior of quantum matter at ultrashort time scales, one of the most complicated and important problems of modern physics. here  , we propose a simple but fundamental approach to study the nonlinear effects of the exciton - exciton interaction on the optical absorption spectrum using the density - matrix representation of the tddft equation for the polarization of a gaas quantum well in a fwm experiment. with the use of the available knowledge of the asymptotic limits of the xc kernels at low and high frequencies and some experimental data, we construct the non - adiabatic part of the kernels that are able to describe the effects of both the excitation and the dissociation of the gaas well in the two heavy- and light - hole valence bands of the three - band case. by means of these kernels,   we show that the effect of
we present a model comparison technique, which uses principal component analysis ( pca ) to convert simulation output into a set of linearly uncorrelated statistical measures, analyzable in a consistent, model - independent fashion.   the method is appropriate for ascertaining statistical equivalence of a model replication with its original implementation, and it automatically selects output features that are most likely to be statistically equivalent to the original model. besides model - independence,   this technique also has three additional desirable features : a ) it automatically chooses output features based on the results of the reimplementation ; b ) it provides a robust and ready to use output comparison method ; and c ) it reduces or eliminates uncertainty of how to validate reimplementation results.database url : http://www.cbi.ncbi.nlm.nih.gov/pubmed/content/5/10/1471-1/7/17
the crank - nicolson ( cn ) implicit integration scheme for the time - dependent nonrelativistic schrdinger equation is improved by allowing for relatively large step sizes both in time and in space.   the new method is based on the fast fourier transform of the second - order spatial derivative of the kinetic energy operator, which is a well - known extension of the crank - Nicolson implicit integration algorithm for the one - dimensional solution of the wavepacket scattering problem. to improve the accuracy of the proposed method,   we have introduced a new set of boundary conditions for unconfined systems that allow for the use of a single - stage time evolution with an error of @xmath11.    the new boundary conditions are found to be very useful for making long - time or large - space problems tractable while still obtaining accurate numerical solutions.
the spin - boson model of a two - level system ( tls ) coupled to a harmonic oscillator ( ho ) is well suited to describe the effects of the environment on the dynamics of the tls.   it has been shown in @xcite that the effective spectral density of the ohmic bath can be exactly mapped on the model of an ohmic tls and a single ho of frequency @xmath0, where the latter feels the influence of an Ohmic bath. here   we show that the same mapping can be applied to the josephson flux qubit read out by a dc - squid coupled to an lc - circuit coupled to the structured bath. using the non - interacting blip approximation ( niba ), which is non - perturbative in the coupling between the qubit and the oscillator, we find that the dipole moment of the squid is reduced by about 50% at low frequencies but not by much more than 10% at high frequencies. for a strong coupling, this reduction is due to the fact that the noise from the environment is transferred to the qu bit, which leads to decoherence and dissipation within its dynamics. however, for a weak
dwarf nova ( dne ) outbursts are one of the most important phenomena in the universe.   however, there is no unique model that predicts these cycles, as well as their underlying mechanism. here   we show that the thermonuclear runaway ( tnr ) model can be used to explain the outburst - quiescence cycle of dw cnc, a dwarf nova system whose first observed outburst was due to a mass transfer event. by combining time evolution of the accretion disk together with thermonucleus burning due to accreted material, the secondary instability model ( sim ), which is generally accepted as the best available model for predicting dneoutbursts, shows good agreement with the observed behavior of the system. moreover, the tnr model accounts for both classical novae ( cne ) and dne out bursts and its application has interesting implications, even if the improvement of the model launched by shara ( 1982 ) never brought to a decisive point.
we propose a model that describes the motion of the magma column in a volcanic conduit as a creep flow of viscoelastic compressible medium with shear - stress - dependent boundary conditions.   we show that the dynamics of the model indeed exhibits 2 levels of quasiperiodic behavior and resembles the eruption patterns of the strombolian - type volcanos both on long and short time scales. for the latter, we derive simple analytical expressions for a dormant time, a duration of explosion, and a typical period of tremor, and then present a numerical solution to a system of dynamical equations describing the motions of the Magma column using the material properties of the active magma.
the opacity - modified eddington limit in stellar atmospheres can occur at significantly greater gravities than the classical one, as is evident from the calculations of lamers & fitzpatrick ( 1988 ), gustafsson & plez ( 1992 ) and asplund et al.   ( 1996 ). here   a similar investigation is carried out for the h - deficient r coronae borealis ( rcrb ) and related stars, where the opacity instead is dominated by continuous opacity. to investigate whether the presence of a gas pressure ( @xmath2-inversion ) in the atmosphere of these stars is associated with the existence of the eddinton limit, it is shown that the luminosity of the system is locally higher than the upper luminosity limit for stars, which coincides with the location of the limit in the equation of hydrostatic equilibrium. if the limit is present, it may prevent the evolution of stars into the super - Eddington regime by the development of radiative instabilities, which may give rise to the eruptions of the luminous blue variables.
shock waves occur in many physical situations in nature.   when such a shock hits an obstacle ( steady or flying ), it experiences a reflection - diffraction process, and then a fundamental question is what types of wave patterns of reflection -diffraction configurations it may form around the wedge. here  , we review the fundamental issues for shock reflection - Diffraction phenomena, especially the global structure and transition of different patterns of shock reflection-diffraction configuration, which are the core configurations in the structure of global solutions of the two - dimensional riemann problem for hyperbolic conservation laws. to achieve this,   it is essential to establish first the global existence, regularity, and structural stability of solutions of solution of the shock reflectance - diffractory problem. as a result, we present a new method for the determination of the transition criteria between the different patterns with respect to the initial - boundary value problem by means of rigorous mathematical analysis. using the monte carlo method, we show that the transition criterion for the three - shock configuration is the same as the one for the regular reflection pattern, but the difference is only a few fractions of a degree apart. on the other hand, we find that
the pion distribution amplitude ( da ) is an important element for applying the qcd factorization theory and qcd light - cone sum rules to exclusive processes involving pion.   the pion leading - twist da has attracted much attention after the pioneering works done by refs.@xcite. in the present paper, we shall adopt the shifman - vainshtein - zakharov ( svz ) sum rules under the background field theory to make a detailed study on the pions leading - Twist da up to dimension - six operators. as the first time, we will expand both the quark propagator and the vertex operator @xmath0 up to a more complex form with full dimension -Six operators contributions so as to achieve an accurate qcd sum rule estimation. using the svz sum rules, we show that those dimension - Six operators shall result in new dimension - 6 condensates that do provide sizable contributions and should be taken into consideration for a sound estimation, i.e. they shall bring sizable changes in our previous predictions on the behavior of pion da.
a symmetric superconductor - insulator - supercond conductor ( sis ) mixer with the same superconducting material for both junction electrodes is proposed.   the interface between the nb tunnel junction and the nbtin embedding circuit is made of superconducted transmission lines which are contacted to the same electrode on one side of the sis mixer and the other side by a normal - conducting metal layer of au. in order to exploit the full frequency mixing range of a high - sensitivity nb sis Mixer,   it is crucial that the tunnel junction is embedded in a high- q tuning circuit that enables a near 100  % coupling to the sky signal. here   we show that the relaxation of nonequilibrium quasiparticles in an added small normal - metal layers of au between the two electrodes of the interneurons can be achieved by replacing the al layer with a good low - conductance al layer. this effect is independent of the geometry of the au layer and does not depend on the size of the overlap between the electrodes.
we present a novel approach for the analysis of microdata with known inter - record distances.   we introduce a graph theoretic linkage attack on microdata that contain spatial information, which is based on a flexible natural graph model for microdata and is applied to a small - scale example of a data snooper s attempt to identify an individual from a microdata file by means of a cross - sectional search for a maximum common subgraph between two such graph models.  in addition, we show that, on the basis of simulated data, a non - negligible risk of identity disclosure exists if @xmath0-distributed gaussian noise is added to the input coordinates for too small values of@xmath1. for larger values of @x math1, however, the data become nearly useless for further analysis due to the release of more accurate ( approximate ) distances. this study shows that it is possible to achieve a trade - off between data utility and disclosure risk through the proposed method.
the most general scalar - tensor theory is the galileon theory, which has second order field equations and second order energy - momentum tensor.   it is based on the einstein - hilbert action with a cosmological term in the gravity sector, while the matter sector is given by a real scalar field with a non - minimal kinetic coupling. in this work   we consider the following action principle : @xmath15=\int\sqrt{-g}d^{d}x\ \left    0. \label{action}\ ] where we have taken the e Einstein - hilsbert action for the gravity sectors and the scalar fields for the matter sectors.    the possible values of the dimensionfull parameters@xmath17 and @x Math18 will be determined according
we report an outburst from a transient x - ray source in the m31 bulge.   coordinated optical observations of the source reveal no variable optical counterpart candidate and show that its optical counterpart must have been fainter than @xmath8. as the sample of such systems grows, it will become possible to perform statistical tests, using properties such as the luminosity and period distribution of the sample to test models of binary formation and evolution.
the study of the distribution of exoplanets semi - major axis could provide useful insights into the planetary migration and protoplanetary disc evolution process.   we perform numerical modelling to explore the influence of different photoevaporation models and of the initial planet mass function on the final distributions of ex planets semi -major axis, in order to explore whether the latter can be used to constrain the initial conditions and the nature of the photoevaporating radiation. using a new code we developed to this aim, we find that depending on the type of photoevagination model and the initial global mass function the shape of the dispersal radiation changes dramatically. for example, combined x - ray and euv ( xeuv ) photoev vapour rates are roughly 100 times larger than pure euv photoevaboration rates, and xeuV photoevatoration rates as a function of disc radius are not so strongly concentrated at the gravitational radius as in the pure euv case. these large differences   should result also in different final distributions with respect to the observed distributions, meaning that observed distributions may provide a constraint on the dominant disc dispersal radiations. furthermore the initial world mass function may also have an influence on
accurately determined parton distributions are an essential ingredient of precision hadron collider phenomenology.   perturbative quantum chromodynamics ( qcd ) corrections are the most important part of these corrections, but they have only a very small effect on the evolution of quarks and gluons. in this paper   we show that the qed corrections can be taken into account by modifying the normal dglap evolution equations, and the resulting set of qed - corrected partons is compared with the results of a standard qcd - only global analysis. for the first time  , we find that the photon parton distribution of the proton is large enough to be measured experimentally at @xmath12 collisions at hera, by compton scattering at wide angle off the electron beam.
deep learning is a promising new area of research in statistical machine learning.   it is based on the learning of a hierarchy of useful representations of data, which are better suited to the task at hand, and are organized in a hierarchy with multiple levels. here   we ask the following questions : do the good results previously obtained with deep architectures on the mnist digit images generalize to the setting of a much larger and richer ( but similar ) dataset, the nist special database 19, with 62 classes and around 800k examples?   to what extent does the perturbation of input images ( e.g. adding noise, affine transformations, background images ) make the resulting classifiers better not only on similarly perturbed images but also on the original clean examples?we study this question in the context of the 62-class and 10-class tasks of the nyst - spanish - national - institute - of - medical - sciences ( nist ) special database19. using the self - taught learning   @xcite framework, we use highly perturbed examples to generate out - of -- distribution examples and test them on 62 different classes and on 10 or 26 different classes of human - level
we report the detection of off - pulse emission from two long period pulsars psr b0525 + 21 and psrb204516 using the interferometric mode of the giant metrewave radio telescope ( gmrt ) in the 325 mhz frequency band.   the observed emission is consistent with emission from open field lines, where the main - pulse is a circular beam arising from the polar cap region of the pulsar, and from a height above the magnetic pole equal to 12 per cent of the radius of the light cylinder. however, in a few pulsars, low level emission components known as pre-/post - cursors ( ppc )   have been observed outside the main pulses, which are believed to arise from close to the aurora or from regions of closed field lines. here   we discuss the possible sources of these emission components.
in  @xcite barot and marsh ( 2012 ) provided presentations of finite weyl groups in terms of arbitrary quivers or diagrams of finite type.   the goal of this paper is to use these presentations to construct hyperbolic manifolds, in particular ones of small volume. using these presentations, we construct a cw - complex with a proper action of the group @xmath9, where the group@xmath10 depends on the mutation class of a quiver / diagram only.
charge transfer is a ubiquitous physical process affecting biological, chemical, and materials systems.   it is essential to use a charge - dependent energy model which behaves correctly for all configurations encountered in the process of interest. here   we show that the piecewise linear model of the charge dependence of the energy for a diatomic molecule can be used to describe charge transfer reactions where the charge @xmath2 is not necessarily an integer.    the model is shown to be more accurate at large separations than the quadratic model.
embedded solitons are solitary - wave solutions of nonlinear evolution equations which reside at discrete points inside the continuous spectrum of the linear wave system.   the existence of such waves has been known in various physical systems such as the fifth - order korteweg  de vries ( kdv ) equations and the generalized second - harmonic - generation ( shg ) system. in @xcite,   such waves were given the name " embeddedsolitons ", and their distinct semi - stability property was revealed on heuristic ground. in this article, we study the evolution of perturbed neutrally stable embedded Solitons in a general hamiltonian fifth - orderskdv equation using the normal form analysis developed in@xcite but simplify many statements and proofs. when an embedded soliton is perturbed, it sheds the continuous - wave radiation in front of the soliton. by controlling the energy ( momentum ) of the initial perturbation  , we can induce either asymptotic persistence or its rapid disappearance.
diffraction is a powerful tool for the study of the dynamics of proton - proton interactions.   it is used to investigate the interaction of electrons with protons in a collider, where the proton is completely destroyed and the interaction leads to jets and proton remnants directly observable in the detector. as an example, we describe the methods used by the h1 and zeus experiments at hera, desy, hamburg in germany, where electron and jets are produced in the final state. here  , we discuss the different experimental ways to define diffraction : the first is to request a rapidity gap in the forward region of the detector ; the second is to detect directly the intact proton in its final state ; the third is to use special detectors called roman pots to detect protons scattered close to the beam ; and the fourth is to reconstruct the transverse momentum of the scattered proton and thus the diffractive kinematical variables.
the initial spin period of a pulsar, @xmath6, is difficult to measure as it requires the knowledge of the pulsar s age and its spin - down behaviour.   we present a timing proper motion measurement for the 143-ms pulsar j0538 + 2817 which was found within the boundaries of g180.0@xmath201.7, also called s147, a supernova remnant ( snr ) that originated in the same explosion as the pulsa. using this measurement  , we obtain accurate estimates of the age of the pulsesar and derive its initial Spin Period.
galaxies have merged frequently with each other throughout the history of the universe.   coalescing supermassive binary black holes ( smbbhs ) are among the most powerful emitters of gravitational waves in the universe, and their detection is essential for understanding the assembly history and demography of black holes, and of galaxy formation and evolution across cosmic times. identifying smbbh systems in all stages of their evolution is therefore of great interest, and an intense search is currently being conducted to identify pairs, smbhs, and candidates. here  , we review the current state of knowledge about the evolution of galaxy and smbh mergers, and discuss recent advances in our understanding of the mechanisms by which they form.
electron transfer is of fundamental importance to proteins whose functionality relies on redox reactions with other proteins, cofactors, or the external environment.   electron transfer through individual molecules has been probed recently using electrochemical scanning tunneling microscopy ( ec - stm ) and resonant tunneling models. in this work, we fabricate and measure single - electron transistors composed of the heme - containing protein myoglobin ( mb ). by applying a bias voltage between electrodes and a gate voltage to the sample s substrate, molecular energy levels can be probed and characteristic single- and double - electron transistor behavior, such as a coulomb blockade or a kondo resonance, can be observed. because the characteristics of the break junction itself after the breaking process can affect the measurements, control experiments must be performed to validate the data. here   we describe the experimental techniques used, including break junction fabrication, electrical measurements, and protein incorporation. for the first time, we show that tunneling is a viable electron transfer mechanism in redox proteins such as myoglobin. from the results of our experiments, we propose that the mechanism of electron transfer in mb is due to inelastic tunneling from discrete vibr
the gratings data catalog at the chandra ( http://www.chandra.org/gratings/ ) is a public resource for the collection and analysis of gratings observations from the public chandra observatory.   the catalog is comprised of three major components : the processing system that collects and processes new public data, the interfaces used for administrative review, and the interfaces and systems provided for user access. in order to achieve this goal the catalog must both have the absolute best processed and calibrated data, as well as have an interface which makes it easy for users to find, review and download their observations of choice. here   we describe the main components of the * _ _ tgc__at * processing system, including the process of collecting and processing new public grands observations, the databases used for storing meta - data and the processing software used to process the data, and finally the interfaces available for use by users.
we have modeled the main classes of sources detected at mjy and sub - m jy flux levels using data from a number of available surveys.   the models are constrained by using all the samples available in the literature, while we focused on samples with optical spectroscopy follow - up to get constraints on the redshift and magnitude distributions of the sources.the models used here provide a good fit to the observed number counts along the entire flux range spanned by the counts ( @xmath2@xmath0jy - 1 jy ) and can reproduce the total number of sources in the comparison samples within a factor of 2. for the first time we show that the composition of the radio sky changes with flux and that radio galaxies reappear in large proportions going to nanojy levels.
we present exact solutions of the ( 0 + 1)-dimensional kinetic ( boltzmann ) equation for a massive gas in the relaxation time approximation  @xcite.   our results describe a purely longitudinal boost - invariant expansion and may be useful for description of very early stages of relativistic heavy - ion collisions.
the rossiter - mclaughlin effect ( rm effect ) is an apparent radial - velocity anomaly that is observed during planetary transits.   we report here on our new observations with the subaru 8.2 m telescope, covering a full transit of hd  17156b and providing the larger and more precise radial - velocities dataset for the system around the transit phase. using the high dispersion spectrograph ( hds : @xcite ), we observed the rm effect over 6.5 hr at 4940    0.9   in the region of the star s spin axis. by measuring and modeling this anomaly,   one can learn the sky - projected angle between the stellar spin axis and the planetary orbital axis, denoted by @xmath2. to the extent that these premises are valid, observations of the rm effects in transiting planets allow us to test planet migration models, including type ii migration, planet - planet scattering, and kozai cycles.
we report a comparison of numerical results obtained by the classical truncated boundary approach with a shooting method, those found by our free boundary approach for the numerical solution of bounded value problems on infinite intervals, and the ones obtained by a finite difference method defined on a quasi - uniform grid.   the numerical results are compared for a steady - state wind - driven ocean circulation model, by considering the barotropic barotropic flow of an incompressible fluid over a slender parabola of revolution in a semi - infinite pile embedded in soft soil. to achieve an accurate solution,   it is necessary to derive special finite difference formulae on the grid involving the given boundary conditions at infinity, but the last grid point value ( infinity ) is not required. for this end  , we derive a series of new finite difference formsulae based on the free boundary formulation for the solution of a bounded value problem defined on an infinite interval. as a consequence, we obtain more accurate numerical results than those obtained from the classical approach with the same values of the truncated boundaries.
the electronic states of ( tmttf)@xmath2scn, a molecular based q1d quarter - filled material, are disproportionated along the chain direction by measuring dielectric response,  @xcite xrd ( x - ray diffraction ),   @xmath0c nmr spectra, which is triggered by anion ordering.   the contrasting temperature dependence of the linewidth of the spectrum and nuclear spin lattice relaxation rates @x Math1 for distinct lines indicates that the order of anions generates local and random potentials at the charge - donating inner carbon site. in this report  , we demonstrate the charge disproportionation in ( ttmt@x maths4f]@x math5__m__f@xMath10 ( _ _ m__=as, p ) by the @xmr spectra using the electrostatic interaction between the ordered anions and inner carbon sites that is much closer to the anions than the outer sites that can lead to the @Xmath8-cdw charge configuration which includes the local and Random electronic state.we propose the instability toward the charge density wave ( cdw ) which has a commens
we investigate the validity of a poincar inequality and a related sobolev inequality for spectral homogenization of a discrete disordered medium that belongs to a class of random conductance models on the lattice @xmath0 with stationary and ergodic conductances on nearest - neighbor and unbounded - range connections.   we use stochastic two - scale convergence, an analytic method that is based on the er godic theorem, to show that the solution to the heat equation satisfies a local limit theorem for the heat kernel in the case where only nearest neighbors are connected. using this method  , we also show that it is possible to obtain a large deviation principle for the occupation time measures of a reversible random walk in bounded domains.
the observed scaling relation between the masses of black holes and galactic bulges strongly suggests that galaxies co - evolved with their galactic nuclei during the hierarchical formation of galaxies.   we show evolution of the central stellar and gaseous cores on a sub - kpc scale during formation of a small ( total mass is @xmath15 ) spiral galaxy through the hierarchical mergers, using high - resolution n - body / sph simulations ( one sph particle has@xmath16 kpc and a softening length of @x Math17 pc ). in order to model the multi - phase nature of the interstellar medium, we use a shear - free formulation of the artifical viscosity to reduce unphysical angular momentum transfer in a shears - free flow @xcite. by solving an energy equation with the radiative cooling below @x math18 k and the inverse comption cooling, we show that the gas mass in the central region of the galaxies is linearly proportional to the black hole mass, i.e., the ratio between the supermassive blackhole mass and the stellar mass of the galactic spheroidal galaxy at the time of forming the galaxy is ~1.5 kpc
the discovery of the first binary pulsar, psr  b1913 + 16, by hulse & taylor ( 1975 ), has permitted precise tests of the general theory of relativity ( gr ) for the first time in the strong - field regime @xcite.   we review the most recent results of observations of these two pulsars, and present a search for new pulsars that are suitable for sensitive gr studies.
holographic dark energy ( hde ) model is an attempt to apply holographic principle of the theory of quantum gravity to dark energy problem.   it is a dynamical model of dark energy where the energy density of any given region should be bounded by that ascribed to a schwarzschild black hole that fills the same volume. in the present work   we first assume hde model for @xmath10 and then we consider modified holographic dark energies model at ricci s scale ( mhrde ).. we will study the models qualitatively and will check for the correlation between the observed value of cosmological constant and the proposed model.,the results show that both the models are in good agreement with the experimental data. however, only the modified model is found to be significantly more accurate than the other two models.
the bardeen - cooper - schrieffer ( bcs ) theory reveals the phase transition from a landau fermi liquid into superconductivity in conventional superconductors, such as cuprates @xcite, iron - pnictides @xmath3al@xmath4 and heavy fermions @Xmath5.   however, the most serious challenge to the theories is to elucidate the non - fermani liquids and superconduction on the same footing. here, we take advantage of a dual fermion model or kondo - heisenberg - like model to explore the generic cuprate phase diagram in the lower - energy band where the carrier and the cu hole have opposite spin orientation in the same spin orientation. using the hole notation,   we show that the phase diagram is dominated by the copper - oxygen planes in cuprates, which can be further reduced to a simple three - band model including both localized and conducting electrons based on the interaction between the localized and itinerant electrons. with the introduction of the introduced carriers, the introduced electron quasiparticels gradually melt antiferromagnetic order and eventually lead to superconductive behavior. remarkably, different
congested traffic is a complex phenomenon, which is characterized by a wide and two - dimensional scattering of traffic.   kerner and rehborn have previously proposed to classify congested traffic into three phases : ( 1 ) free flow, ( 2 ) " synchronized flow ", ( 3 ) wide moving jams, and ( 4 ) localized clusters of traffic whose width in longitudinal direction is considerably higher than the width of the jam fronts. in some applied empirical studies, however, kerner also suggests to distinguish a fourth state of stop - and - go traffic, i.e. congestion. here  , we present a new patent for a new method for the analysis of Congested Traffic, called @xcite, which takes advantage of the recently published results of kerner et al. in their recent paper on the theory of traffic dynamics with respect to high - density traffic ( j. traffic comput.2013, 9, 5861 ).    the patent is available at http://www.biomedcentral.com/1741-7009/7/5241.
the classical gibbs - donnan equilibrium is usually invoked to explain various behaviors in ionic systems : swelling of polyelectrolyte gels, membrane potentials and osmotic shock experiments of cells or viruses.   the physics behind these phenomena is associated with some colloidal charge confined within a subpart of the system, while small co- and co- counter - ions can diffuse freely in and out of this region. in systems either where colloidal charges are large or where the buffer solution contains multivalent ions, the gibbs's equilibrium has to be extended to take into account the electrostatic binding of counterions onto the colloidal charged system. in this letter  , we propose such an extension in order to include multivalent ion binding effects in the classical gibbbs -Donnan approach.    we find that the repulsive force ejecting dna from bacteriophage lambda @xcite as a function of multivalent salt concentration decreases and then increases, upon increase in the added salt concentration. at the same time, the minimum in the force is associated to the charge neutralization point of dna, which correlates well with experimental results.
we report a study of the correlation between irreversible rearrangements and local softness in actively deformed polymer glasses.   we use molecular dynamics techniques and the well - known finitely extensible nonlinear elastic ( fene ) bead - spring technique to study the relaxation of a model polymer glass under uniaxial tensile deformation and compare it to the simple shear protocol used in previous simulation studies. during the aging phase,   correlations grow due to a descent into deeper energy minima, but return quickly to their as - quenched values once plastic flow sets in. in the deformation phase, correlations rise again with increasing strain, which we show to arise from an increase in the degree of localization of the soft modes as the aspect ratio of the sample changes. during recovery, correlations increase only weakly as inherent structure energies return to their undeformed values.
the association between meteoroid streams and comets is well - established, though the idea that some originate from asteroids is quite old.   the major tool for determining a pairing of parent and meteoroid stream has been orbit similarity. to quantify this, southworth & hawkins ( 1963 ) and drummond ( 1981 ) proposed orbital similarity d - criteria, both being widely used. using such criteria, many pairings between comets and meteor streams have been established and also between minor showers and near - earth asteroids ( neas ). in order to discriminate between the orbits of cometary and asteroid meteoroids,   several one parameter criteria have been proposed, they are listed in jopek & williams ( 2013 ). here   we review the use of these criteria to classify sporadic meteoroids collected from several sources.
three - dimensional solutions of the magnetohydrostatic equations in cylindrical geometry have been found using a systematic method for finding a special class of three - dimensional magnetohysdrostatic equilibria in external gravitational fields.   the method is based on the presence of an external force derived from a potential, for example gravitation, and assumes that the electric current density has specific properties to allow analytical progress. here   we show that the method can be used to find three - dimensionally explicit solutions of these equations for a cylinder of radius and infinite length rotating rigidly with constant angular velocity co - rotating with the cylinder. by taking into account the existence of free boundaries between the closed field line regions of rotating magnetospheres without symmetries,   a number of solutions are found for the magnetic field, the current density and the centrifugal potential.the results are discussed in terms of the theoretical framework and the solutions are presented as a step towards solving the global problem of modeling magnetosphere.
we present a first study of the ultrarelativistic scattering of two black holes ( bhs ) in the superkick configuration, in which the masses are equal in magnitude, opposite in direction, yet within the orbital plane, the recoil velocity can become quite large, a phenomenon that is sometimes called a _ superkick.   we find that the recoil direction is orthogonal to the orbit, and the magnitude varies sinusoidally with the initial phase of the binary, with a maximum proportional to the net linear momentum radiated in gravitational waves.. this is completely consistent with the original scenario where the bobbing - induced blue / red - shifting of the radiated energy leading to the recoil is purely kinematical in nature, and not responsible for the recoil.
the vortex structure is observed in nature in a wide range of phenomena, from tornadoes and hurricanes in atmospheric phenomena to superconductivity.   it is present in confined structures like disks, triangles, squares and wires ( or stripes ) in micron and submicron scales. here  , we investigate the dynamics of vortex domain walls traveling and interacting with triangular asymmetric notches on permalloy ( py ) nanowires. through the focused magneto - optical kerr effect ( moke ) and micromagnetic simulations, we show that the vortex wall chirality can be tailored when the wall interacts with a defect with a particular symmetry, here, a notch, and what should be the Vortex wall dynamics.. the main idea is to change the notch symmetry by changing the outgoing angle @xmath2, to be able to continuously vary the potential barrier generated by the notch. using the focused moke, we demonstrate that the shape of the hysteresis loop and the coercivity of both chiralities, cw and ccw, and mainly their relative occurrence probability beyond the notch, are determined.
we investigate the effect of time - dependent radiative transfer on the temperature profile of the atmosphere of two eccentric transiting planets, hd  80606b ( @xmath1 ) and hd.   we calculate the time scales for the atmosphere to respond as a function of orbit eccentricity and depth in the atmosphere using a model that takes into account the time - variable stellar irradiance impinging on the atmosphere by varying the rotation rate of the planet. with an eccentricity of 0.93 and 0.432   k, we find that the temperature - dependent adiabatic lapse rate is approximately 1.0  0.2  ms for the upper and lower atmosphere layers, respectively, and about 1.5  0% for the lower atmosphere layer. this difference is consistent with the observed observation of a very rapid increase in the temperature at the surface of the inner atmosphere of one of the most eccentric planets, wasp-10 b, which has a diameter of 2.7  0,000 km.    we conclude that the observed observations are not sensitive to the time variation of the exoplanet s atmospheric properties.
pulsating white dwarf ( wd ) stars provide a unique opportunity to probe their internal structure by comparing the observed spectrum of pulsation periods with the predictions of detailed asteroseismic models.   the ongoing extremely low - mass ( elm ) survey has led to the identification of seven pulsating elm wds including the unique system psr  j1738 + 0333  @xcite. in this article  , we describe the pulsation models for these candidates and we present our timeseries photometric observations. using the montral pulsation codes @xmath90141, j1141 + 3850, J1157 + 0546, j1238 + 1946, j1625 + 3632, and j0756 + 6704, we find that all of the previously discovered pulsators are found to be excited in their models. in all three cases,   h / he mixtures are found in the atmosphere which could potentially lead to pulsations with 200  800  s periods. however, no excitation was found in similar models for the three other spectroscopically excited @x Maths2- or @x math7-mode pulsators. as a result
@xmath0 car is a luminous blue variable of extremely high mass in a late phase of its evolution.   the stellar photosphere, as well as nebulosities both close to @x Math0 car and beyond the homunculus indicate significant carbon and oxygen ( cno)-processed material within the soft x - ray emitting shell surrounding the central emission core containing @x math0 car.    observations using _   hst_/stis of the central emissions core at distances of @xmath4 200 - 600 au reveal a complex of narrow circumstellar absorption lines representing at least 20 distinct velocity components in the line - of - sight toward @xMath0 car.this paper presents the observationally derived column densities for ch and oh and upper limits for other relevant molecular and atomic species in the @x mathematics1513 kms@x maths2 component. examination of high resolution spectra acquired with the e230h grating reveals definite detections of six absorption lines from ch and two probable oh line detections in the wavelength region between 3070 and 3150.the observed ti ii, c i and ch column density values serve as a basis for photoionization modeling that
we report time - varying spectral features in the late - time x - ray afterglow of grb130925a  that were initially discovered by _ nustar_ and confirmed in a second epoch by   _ chandra_. our detections are at higher energies and significantly later times than previously reported afterglowing features.   we find evidence of two separate blackbody components in the afterglows of several ultra - long gamma - ray bursts ( grbs ), one with a radius of 27 cm and the other with a diameter of 1.5 cm, both of which have been reported to be associated with large - radius progenitors @xcite during the early - time ( @xmath4s ) emission episodes of the burst.    the detection of these components is consistent with the hypothesis that they arose from the formation of a blackbody component in the initial burst phase.
soliton models of nuclear matter are based on the assumption that the quark wavefunctions of all states in the band are @xmath6-wave states, and that the dispersion relation is independent of direction.   this assumption is supported by the fact that the bloch condition gives boundary conditions on the wavefunction within a single cell for all values of the crystal momentum@xmath4 within the first brillouin zone, with the lowest energy state corresponding to @x math5 and the energy gap above the highest energy state as the top of the band. here   we present a new approach to the calculation of the quantum hadrodynamics of soliton matter using the wigner - seitz approximation @xcite, which takes advantage of the existence of a spherically symmetric schrdinger wavefunction for the state at the bottom of the Band. from this   it is possible to calculate the density of the quarks in the range of crystalline nuclei, and the inter - nucleon separation between the lowest and highest energy states over the band under the same experimental conditions.
the reverberation mapping technique is a mathematical method that can be used to study the geometry and kinematics of the gas in the broad line region ( blr ), and to deduce the mass of the central black hole ( bh ) in the center of the active galactic nucleus ( agn ).   the technique is based on the response of the ambient gas to changes in the central continuum source. over the past two decades   many monitoring campaigns have been carried out and enabled the measurement of @xmath10 in about three dozen agns. in this review   i will summarize the current situation and recent studies using reverberation map analysis.. i will also try to point on directions i think reverberation maps should take in the near future.
the slow- or rapid - neutron capture process is a process that has been proposed to have formed the majority of the elements in the early galaxy.   the abundances of the slow - capture elements zr, ba, nb, pd, and ag have been studied in a wide range of galactic stars over a range of metallicity. here   we briefly review some of the important trends in the abundance distribution of these elements for the ultra - metal - poor ( @xmath0 ump,  = 3.1 ) but neutron - capture rich halo star cs  22892052 @xcite. at very low metallicities high mass ( and rapidly evolving ) type ii supernovae   contribute to galactic iron production. at higher metallicities, however, the onset of the bulk of iron production from type iasupernovae ( with longer evolutionary timescales due to lower mass progenitors ) occurs only at higher @xmath2 + 0.5 and later galactic times. as the rate of evolution of the solar system   rubricates the spectrum of the _ r_-process elements, the observed abundances in
we investigate the spin relaxation mechanisms of a hybrid mn - hole spin in charge tunable cdte / znte quantum dots ( qds ) coupled to a single mn atom under resonant excitation with circularly polarized light @xcite.   we show that the induced resonant photoluminescence of the positively charged exciton ( x@xmath1-mn)coupled to a magnetic atom in the qd is driven by an efficient mechanism of spin relaxation, which is mediated by the exchange interaction between the confined heavy - hole and the spin localized on the magnetic atom. for an efficient coherent control and a practical use of this hybrid spin in a quantum device one would require however sufficiently long relaxation and coherence times for the two ground states of the optical @xmath0 systems.
the diffuse ionized gas ( dig ) is visible as an extended h@xmath0 emitting layer in our galaxy and in many other galaxies.   studies of emission line ratios such as /h@x Math0 and /.   so far photoionization models have made no specific attempt to model the trends of the line ratios. in this paper   we are constructing new models of the dig using the data taken from the wisconsin h@Xmath0 mapper ( wham ) survey which were kindly provided by ron reynolds and matt haffner, and compare them to the observed emission line ratio /H@x math0 and+/h @xmath 0. for the first time  , we show that the heating rate of the gas can be used to heat up the gas sufficiently to explain the observed line ratios with increasing distance from the midplane.    we also show that it is possible for ionizing photons from o stars to penetrate through the halo into the gas.
the asteroseismology group at the institute of astrophysics and geophysics of lige has been using an evolution code derived from the henyey code since the early 70s.   this code has been continuously updated, but it became clear that the frequencies and the stability of the oscillation modes were extremely sensitive to details of the model, which were unimportant for the computation of stellar evolution. a few years ago, it was thus decided to write a new code, meeting the specific requirements of our studies in asteroseistology.the current version of the code is named cls, the acronym of _ code ligeois dvolution stellaire_. it is still in an active phase of development. as it is easy to customize, several versions of the software have been developed from the standard version, implementing different features needed by the works already realized or in progress.    the most interesting of these will be included in the next standard version of Cls so as to preserve its uniqueness. due to limitations in the physics already implemented, the present version of cls is not intended for the helium burning phases of the evolution.the main objective of this effort is to have a versatile stellar evolution code producing
we perform a 2d full particle simulation of a high mach number and low - beta perpendicular collisionless shock in a self - consistent electromagnetic particle code @xcite.   the experimental results show that the electron surfing acceleration is suppressed in a two - dimensional system.
computer simulations of polymer systems are increasingly being used as an integral part of theoretical study, in order to both test existing theories and to trigger the development of new concepts.   computer simulations have also become an essential tool in materials research, especially for predicting and understanding the behavior of complex systems, where a complete theory is not available. while the advantages and disadvantages of the methods are well - known in general terms ( and have resulted in differing methodological preferences in different groups of researchers ), not much is known quantitatively in terms of a clear comparison of computational efficiency. here  , we present a new mesoscopic method for simulating polymer - solvent systems based upon a lattice boltzmann approach, which takes into account the solvent - mediated long - range dynamic correlations between different segments of the chain, known as hydrodynamic interactions ( hi ). by means of this method,   the solvent molecules are simulated on a grid, while the motion of the polymer chain is governed by a continuous molecular dynamics ( md ) model. using a simple dissipative force, we show that the proposed method can reduce the necessary cpu time by several orders of magnitude in the dilute limit, in particular in the case of the solvent particles
in @xmath0 models of gravity, the einstein - hilbert action is supplemented by a term that is non - linear in the ricci scalar.   this term has been known to cause acceleration at cosmological scales and densities. here   we explore models with compton wavelengths out to the horizon size and seek to constrain them from Cosmological observables alone. using constraints arising from the cmb angular power spectrum measured by wmap @xcite, the linear matter power spectrum inferred from the sloan digital sky survey ( sdss ) luminous red galaxy ( lrg ) sample, the distance measures by the supernovae legacy survey ( snls ), and the cross - correlation between the cosmic microwave background ( cmb ) and large scale structure as measured bywmap and a range of galaxy and quasar surveys, we show that the unique and strongest signatures of these modifications are on cosmology structure formation and can impact observables down to compton wavelength of a few tens of mpc.    we also show that there are no significant differences in the strength of the effects of the @x Math0 models on the cosmologically relevant properties of the c
glassy systems like spin - glasses and structural glasses below the glass transition temperatures are out of equilibrium even on the macroscopic time scale.   experimentally, the anomalous dynamical behaviors of these systems are characterized by slow relaxation with long time tail and aging phenomena. in this paper, we investigate the experimental time scale dependence of the thermodynamic properties of glassy systems to construct out - of - equilibrium thermodynamics for them based on a dynamical description without the assumption of ergodicity. as a result, we show that the properties described above do not hold in systems with aging. instead, there are two experimental time regimes characterized by different thermal properties : the first regime is a time - domain where the waiting time is much longer than the time lapse of the process. in the second regime,   the principle of the minimum work holds even though a system is out of equilibration.see research article http://www.biomedcentral.com/1471-2148/9/7/8/5
the generalized woods - saxon ( gws ) potential has been used to investigate the binding energies of single - particle and single - hole neutron orbitals in the region around the doubly - magic @xmath1 nucleus @xcite.   the gws potential contains the woods -saxon potential plus a term referred to as the surface ( su ) potential that maximizes the freedom in the surface structure of the potential. using the schrdinger equation, we have obtained the analytical solution of the klein - gordon equation for a spin = 0 particle moving in the gwss potential field. by means of the jacobi polynomials,   these eigenvalues satisfy the boundary condition for any@xmath4 ( spin - orbit operator eigenvalue ) states of an anti - proton being subjected to the g wss potential in the pseudospin symmetry limit.
the aim of this study is to develop a model of envy using plastic preferences.   we show a slight modification of a previous model @xcite and propose a system where the individuals try to adapt their preferences in order to avoid envy, like a system that adapts itself to the environment and will avoid posterior exchange of goods. according to our model,   the individuals search for goods of their highest ranked preference type in the available set of goods from a set of various goods located in a store. when an individual does not acquire her / his desired goods, then she / he starts to look into the neighbor s basket. when the individual find out the searched good into her /his neighbor s baskets an envy relation is bearing @xcites.. the change of believes has no dependence on typical scales of time, but on times of interpersonal comparisons. by means of the simulation method we developed, we show that the variance of the envy relation can be explained by the existence of elastic preferences.
the bardeen, cooper, schrieffer ( bcs ) theory of superconductivity is used to describe pairing in atomic nuclei @xcite.   a consequence of the finite size of the system is the appearance of shell structure, which implies that fluctuations of the pairing gap as a parameter, like the particle number, are varied. in this contribution   we discuss how these fluctuations can be described in a semiclassical theory. using the three - point measure, we first discuss pairing in nuclei obtained from the odd - even mass difference, and then compare the results with experimental data. in the next section a semiquantitative theory of the bcs pairing gap for nano - sized metallic grains is presented, where, due to a lack of experimental data, we compare our theoretical results to other existing numerical results.
swimming is the motion of deformable bodies.   it is not possible to swim in a curved space because the notion of center of mass is a fundamentally a euclidean notion, with no analog in curved space. here   we discuss the problem of non - relativistic swimmers in a given static curved space and present a newtonian model of swimming in which the swimming problem is reduced to a problem in newtonia.
we present a new model of the accelerated expansion of universe that includes diagonal mavan s mechanism in the neutrino phenomenology.   we use the data from the super - kamiokande ( sk ) experiment to study the influence of medium density effects on the propagation of atmospheric neutrinos. for the first time  , we show that the observed angular distribution of events in sk is independent of the density of the medium density and that this dependence is due to the existence of a non - standard neutrini - scalar coupling between the dark energy density and the baryonic matter density. by using the so - called  up - down  asymmetry of neutrine events in Sk as a proxy for the interaction between the two dimensions of the universe, we find that the rate constants of the interactions between the medium densities are not significantly affected by the inclusion of diagonal mvan s mechanism. however, the rates constants of these interactions are significantly influenced by the presence of the cosmological constant of the fast - expanding universe, which is responsible for the acceleration of the cosmic microwave background ( cmb ) radiation.
we present an explicit algorithm for the transformation of any planar or spherical curve into any other regularly homotopic curve.   we show that the diameter of the set of all curves in a given regular homotopy class which have at most @xmath0 crossings, grows quadratically with respect to @x Math0. using the invariant of curves introduced in n1, we prove that the quadratic upper bound is true for both planar and spherical curves.conclusionsthe results are compared to analogous results in other settings, and give a simplified version of our algorithm which may serve as a simple constructive proof of whitney s theorem.
inflationary models predict that the universe is spatially flat, and that the quantum zero - point fluctuations of the space - time metric produce a nearly scale invariant spectrum of density perturbations that are responsible for the formation of cosmic structures and the generation of a primordial cosmic gravitational wave background ( cgwb ).   observations of the cosmic microwave background have provided a confirmation of the first two predictions ; the Generation of primordial gravitational waves is still to be verified. in this paper   we investigate how the direct observation of primorial gravitational waves by the big - bang - observer ( bbo ) interferometer can constrain the parameter space of inflationary models and what are the implications for the design of a mission aimed at directly investigating the signature of these waves. using single - field slow - roll inflation, we show that the spectrum of the cosmically invariant cgwbs generated during inflation can be characterised by only two unknown parameters ; the rate of expansion and the energy density of the gravitational wave stochastic background.    we also explore how such information can be compared with and complement those that can be gained with future cmb data.
quantum key distribution ( qkd ) is the first mature technology which uses fundamental quantum mechanics, and allows for the creation of a secret key between authorised partners connected by a quantum channel and a classical authenticated channel.   it can be performed with both discrete and continuous - variable systems, and can be divided into three basic categories, with different security categorisations and degrees of quantum correlations needed to function effectively. here   we analyse a feasible continuous - variables regime in which one - sided device independent Qkd is available between two participants in a fully tripartite entangled system, while the third can not participate. using a simple travelling wave model, we show that for some systems alice and clare can exchange secret keys which are not accessible to bob, and demonstrate that this is not possible in fully symmetric tripartites entangled systems.
@xmath8  is a candidate nucleus for the simultaneous occurrence of two neutrinoless double beta ( @xmath6 ) decays.   it would prove that neutrinos have a majorana mass component. in this process lepton number is violated by two units and the observation would have far - reaching consequences  @xcite. until recently  , the claim has not been scrutinized. here   we report the results of a direct test using the same isotope and also using mostly the same detectors as heidelberg - moscow ( hdm ) and international germanium experiment ( igex ) experiments. to verify the claim, we analyzed the data from phase  i of the @x Math8  experiment at the laboratori nazionali del gran sasso ( lngs ) of infn in italy using the newly developed  phase  ii detectors of the same material with enriched @xxmath21-type semi - coaxial ( bege ) and reprocessed ~3.63  kg high - purity germania ( hpge ) detectors. among the new detectors,   the one with the highest active volume fraction ( 0.
we propose a non self - similar analytical model for the hydrodynamic origin of accretion powered jets / outflows emanating out from galactic and extra - galactic sources.   the model is based on a virtual surface around accreting compact objects from where inflow and outflow can be simulated in vertical equilibrium using paczy's nski - wiita potentials which mimic the surroundings of the schwarzschild black hole. to investigate the dependence of the mass outflow rate ( @xmath2 ) on various flow parameters, we solve the accretion and wind equations and find that the exact location of the jet launching zone has been successfully pointed out.
the faddeev equations for the he@xmath1he trimer system are solved using a new numerical method based on the use of jacobi coordinates.   the results show that the method is suitable for calculations of weakly three - body bound states and excited states close to the two - body threshold. in the case of strong short range repulsion at short distances   it is possible to obtain high accuracy calculations using low computer power.
a bose - einstein condensate ( bec ) is a state of matter in which a large number of bosons occupy the same quantum mechanical ground state.   becs present the opportunity to study quantum systems which display large scale ( macroscopic ) collective behaviour. in this paper   we analyze the effects of perturbations to the solvable @xmath11-model of a two - component bec on the particle distribution, entanglement and the evolution of the relative number operator. by including additional interactions such as three - body recombination, background collisions, spin exchange and dipole relaxation  , we show that the model is more robust to perturbation than the canonical josephson hamiltonian model.
hydrodynamic interactions influence the dynamics of colloidal particles dispersed in a fluid solvent.   we use brownian dynamics computer simulations to study the steady - state diagram of sedimentation and electrophoresis induced by different buoyant masses of oppositely charged colloids in which hydrodynamic interaction is neglected. for sedimentation, we find that hydrodynamics strongly disfavor laning. for electrophoretic lane formation,   the simulation data are compared to that obtained by simple brownian dynamic simulations where hydrod dynamical interactions are neglected. in both cases, a macroscopic phase separation of lanes   is observed, i.e.  the sickness of the lanes is observed in the absence of hydrod dynamically induced sedimentation.
the charm quark is a key component of the nucleon s  gluon _ distribution, and its presence in leptoproduction remains a matter of debate.   recent data from the h1@xcite and zeus @xcite collaborations at hera have shown that the charm contribution to the proton structure function, @xmath1, of the small-@xmath2 region is around 25%, which is a considerably larger fraction than that found by the european muon collaboration at cern @xa4, where it is only about 25%.. at the same time, there are several lingering pieces of data which seem to suggest that a small component of charm exists which is intrinsically non - perturbative in origin, and which have in the past been taken as evidence in favor of a non -perturbative, or " intrinsic " charm component. here   we use the latest available theoretical techniques for calculating @x Math1, as well as different models for intrinsic charm, to address the question of the presence or absence of intrinsic charm in the @x math1 data. using these techniques, we find that the majority of the data can be described in
form @xcite is a program for symbolic manipulation of algebraic expressions specialized to handle very large expressions of millions of terms in an efficient and reliable way.   it is widely used in quantum field theory, where the calculation of the order of several hundred ( sometimes thousands ) of feynman diagrams is required. as a result, parallelization is one of the most efficient ways to increase performance. here   we report the present status of our project of form parallelization and the result is called parform.parform is a new version of form that allows us to parallelize each step of a process by means of a master - slave structure. at the end of a module   the sorted streams of terms from all processors have to be merged to one final output stream again.the main goal of parallel processing is to reduce wall - clock time i.e. the user s waiting time. with respect to serial execution,   there is no significant difference between the two versions of form, but the parallel version is more efficient than the original version. because of the fact that form only allows local operations on single terms, this makes it possible to handle expressions as " streams " of terms, that can be read
active galactic nuclei ( agns ) are sources of tremendous energy that provide clues to the accretion history of the universe.   x - ray emission is an efficient means of detecting energetic activity in distant galactic cores and is often used to find agn samples @xcite. however, this approach is less successful at finding sources hidden by extreme columns of gas and dust, and models of the observed hard x -ray background require larger numbers of agns than are currently observed. here  , we combine and compare the procedures introduced by these two radio / mid - infrared selection techniques to find a sample of 72 agn candidates in the extended groth strip ( egs ) and use multi - wavelength data to cross - identify their active status. using cold dark matter cosmology, we find that the majority of the agns are compton thick or compton thin with a ratio of 1:1 at redshifts between 0.5 and 1.0 kev. for the remaining agns,   our results show that they are either obscured or near - obscured, and the latter is more likely to occur in the mid - ir than the former.
change detection in remote - sensing imagery from a constellation of lightweight satellites is a challenging problem.   traditional pixel - based change detection techniques have always required a certain artful, ad hoc selection of features and a decision threshold on the histogram of features. here   we present a novel approach to the change detection problem by matching local features across time - sequenced pairs of images derived from the david lowe s scale invariant feature transform ( sift ), @xcite, which extracts keypoints and descriptors defining local features for each of a pair of images. for every keypoint in one image,   a keypoint is sought in the other image that is close to the first in both image geometry and descriptor space. assuming stringent standards in this matching process, matched keypoints indicate a correspondence between local patches in the two images ; unmatched keypoints can result from variations in the way the images were captured, failures of the matching algorithm, or actual changes in structures on the ground. using a binomial statistical model  , we show that the match criterion can be relaxed to a much lower level than it would be for a more traditional match criterion. with the exception of some keypoints that do not match
abstractthe assembly of massive galaxy halos is a complex process that takes place in the centers of massive cluster galaxies.   the formation of the extended bcg envelopes and diffuseacluster light ( icl ) that are found in the center of these clusters is driven by a variety of processes, including tidal stripping, mergers, and accretion of star - forming stars from their host galaxies. here   we review recent studies of the evolution of the icl in massive galaxy clusters using collisionless simulations and observations of the morphology, colors, kinematics, and distribution of discrete icl tracers in the core of virgo s extended halo as well as the diffuseagroup light surrounding ngc 4365, a globular cluster of galaxies that has formed since the early stages of the history of the universe. while the dynamics of these processes are well - known, the contributions of other processes, such as tidal stripping and mergers within the cluster core, are poorly understood. to address this issue, we have developed a new model of the accretion history of each of the most recently formed virgo halos, which accounts for the majority of the observed icl fraction and shows that the rate of
gravitational lenses, or multiply imaged gravitational mirages, are powerful tools in cosmological studies.   they can be used to study the redshifts of distant objects, and to determine the distances to them from Earth by measuring the angular separation of the light travel times of the bundles of light rays emitted by the source and the lensed object. using these techniques,   it is now possible to calculate the cosmologic parameters @xmath1, @x math2 and @x Math0, which dictate the overall geometry of the universe.
we present a new measure of multipartite entanglement in composite quantum systems, negativity, which is based on the density matrix under partial transpose ( npt ).   we use it to study the effects of local depolarizing, dephasing, and generalized amplitude damping channels on the behavior of ghz states and graph states under general local homogeneous noise processes. for each state,   the lower bound of the negativity is set at a value of 0.1, indicating the presence of some form of entangler within the system ; however, it gives little information about its particular form and, therefore, its benefit for some applications remains questionable. by applying the negativity to the dynamics of several - qubit ghz, cluster, w, and dicke states under various local levels of noise, we show that the negative energy of the npt can be used to detect the existence of fully separable entangled states with the help of a non - zero value of the sum of the concurrence and the number of qubits involved in the entangling process. as a proof of concept, we demonstrate that the results obtained using the negativity are comparable to those obtained using other measures such as
the minimum current corona model ( mcc ) has been used to estimate pre  flare energy storage in a number of flares, including the landmark @xcite.   it is now widely believed that solar flares are powered by magnetic energy which had been stored in the corona through slow stressing applied from the photospheric boundary. here   we introduce a new algorithm by which emerging flux regions may be automatically accommodated in the mcc constraints leading to a pre  Flare energy estimate.    the proposed algorithm is based on the use of flux constrained equilibria ( fce ), a quasi - static technique using equilibira to minimize magnetic energy subject to a set topological constraints composing a subset of all line - tying constraints. rather than constraining every pair of footpoints into unipolar photopsheric regions and constrains the net coronal flux connecting each pair of regions,   its fields provide a lower bound on the actual free energy. as the photosphere moves relative to one another the potential field above changes as do the fluxes by which it would link region pairs ( potential domain fluxes ). since the actual field is constrained from changing these fluxes, it becomes increasingly different from the
@xcite and @xcite have developed a 1d, linear, non - adiabatic code with a time - independent mixing length theory for the convective flux that can be used to study the interaction of convection and stellar pulsation in one dimension.   they found that the proposed model is not suitable for calculating pulsation amplitudes for the @xmath7-cephei stars they are studying.
we report on our attempt to detect x - ray pulsations from the gamma - ray neutron star psr b1706 - 44 using the rossi x - rays timing explorer ( rxte ).   the pulsar is a young neutron star ( spin down age 1.75@xmath2 yr ) with a spin period of 0.102 s and a large spin down luminosity of 3.4 @xmath3 at a distance of 1.82 kpc. in this paper   we describe the characteristics of this pulsar, the observation carried out with rxtte and its analysis, and compare the results with the theoretical models of the pulsed radiation mechanism used in the testing and refinement of the existing models.
most document repositories contain linkages between the documents creating a  document - graph.   these linkages provide context to the terms and topics in each document, and are often used to guide readers towards the information they seek. as the number of online resources and web documents continues to increase, the need for better organizational structures that guide readers into the appropriate order of documents and topics has increased. here   we argue that most document - graphs, or, more generally, information networks, contain hidden node hierarchies. by using examples and a review of similar assertions made in previous studies, we show that the internal nodes of many existing hierarchical taxonomy models contain ephemeral word - topic distributions, rather than actual documents. this assertion is consistent with the hdtm model, which requires that inner nodes, which in previous work are made of ephemerally distributions, be literal documents. on the other hand,   the inner nodes of the hierarchical pachinko allocation model ( hpam ) and the tree structured stick breaking ( tssb ) model construct a conceptual taxonomy in which the non - leaf topics are a combination of words and does not represent a real document in the corpus ; the leaves contain the actual
we calculate the tidal forces acting on a photon in an effective field of the orbiting bodies using a metric calculated by taylor and poisson.   we assume that photons move on the null paths and are influenced by a binary system, with two equal masses, in a circular motion. to better discuss the dynamics of this system, we introduce two lengthscales : one scale is given by @xmath5, and the other scale is the radius of the circular orbit, denoted by@xmath6. for the second body in the binary,   the tidal potentials are given by a linear perturbation about the schwarzchild solution ; so that the perturbed metric satisfies the vacuum field equations, perturbatively. in order to obtain the observable variations at any point of the path, we include the force components in the osculating equations given in @xcite.we find that the observed variations are due to the effects of the tidal interactions between the main body of the binary and the gravitating body, as well as to the influence of the secondary body on the geometry of the spacetime.
we construct a generalized universal cover for a very large class of uniform spaces called  coverable _ spaces, which includes all geodesic metric spaces, connected and locally pathwise connected compact topological spaces, and in particular peano continua.   we also consider some more pathological spaces like the topologist s sine curve and totally disconnected spaces. to generalize the results of @xcite, we take into account the notion of a generalized fundamental group, which is a functorial uniform space invariant that is related to the classical fundamental group by a natural homomorphism. using this concept, we show that the generalized universal covers of metric spaces can be considered as quotients with central kernels that are ( complete and ) prodiscrete, i.e., are inverse limits of discrete groups. these generalized covers have the lifting properties of traditional covers, but are not in general local homeomorphisms.
we derive bounds on the social cost of a facility location game played among selfish agents ( enterprises ) over a network.   we use a fair cost allocation rule for facility installation costs : for a location @xmath10 installation cost @x Math11 is shared in a fair manner among agents that receive service from @x maths10, so that agent @x math7 pays @xMath12, where @x mathematical13 denotes the total demand forwarded to @x mathematics10.    we find that the price of stability of pure nash equilibria and strong equilibrian networks are almost exactly the same.. however, for the case of weighted players, the prices of both equilibrium types are significantly higher than those of unweighted players.
the quantum interface between light and an atomic ensemble has attracted much attention during the past decade due to the wide range of possible applications that rely on the coherent coupling between the two systems : implementation of quantum information processing protocols, slow - light and electromagnetically induced transparency as well as the creation of deterministic and manipulable photon sources. in order to create these photon sources, one must be able to create entangled atomic many - body states and map them efficiently into the desired photonic states.   ultracold atoms represent the ideal tool for creating these atomic states under very clean and well - defined conditions. in a recent work   a laser - driven gas of rydberg atoms trapped on a one - dimensional ring lattice has been proposed as a resource to create collective excitations which can be converted into few photons following a mapping scheme proposed in refs.  and . here   we extend this study to a gas of atoms trapped in two - dimensional medium - scale square and triangular lattices and outline methods of selective excitation. using these two lattice types we find that one can create single - photon sources in which the photon is emitted in a superposition of a few
the spliceosome is the rna - protein complex that performs the intron excision.   it can be traced back to the last common ancestor of extant eukaryotes ( leca ), which is almost certain to have had a large number of intron - rich early lineages. in this paper  , we introduce novel computational techniques for the analysis of splicingosomal intron evolution and show that these methods can be used to identify conserved intron orthologous regions in eukarian genomes.
vortex instabilities are observed throughout the universe.   vortices can act as a source of local angular momentum and turbulence, both of which are important in the evolution of molecular clouds. in this paper  , we present simulations that show under certain conditions von karman - like vortics are produced in the wakes of asymptotic giant branch ( agb ) stars with size scales from @xmath0 pc to@xmath1 pc.we model the interaction of a stellar wind with the interstellar medium ( ism ) where the star has a significant motion through the ism. using a computational fluid dynamics ( cfd ) scheme, cubempi, we show that the star ejects a few solar masses of material into the surrounding medium over the course of @x Math8 years. in our two - wind model,   the ejected stellar material forms into a bow shock upstream of the star with a tail flowing downstream. at the tail of the bow shock, we find evidence of vortex - ring instabilities similar to those observed in the atmosphere of jupiter.    we also show that these vorticed structures can be reproduced in 3d by using a riemann solver.
the study of compact stars has been the subject of great interest in modern cosmology.   recently, there has been growing interest to study the compact stars in modified theories of gravity like @xmath0 and@xmath10. in this work, we study the models of the charged anisotropic compact stars using the krori - barua metric assumption. for this purpose, we present a set of solutions of the einstein field equations for the charged strange compact stars by using the relativistic equation of hydrostatic equilibrium with fermion equation of state ( eos ) for the anisotropically charged compact stars as well as the model of @x Math0 gravity with model @x math7 ( where @x maths8 is constant ).    the results show that the proposed solution of the field equations can describe the class of some anisotropy compact strange stars in a very scientific way.. the exact solutions have many applications in astronomy and astrophysics.
ontologies are witnessing an increasing popularity outside specialized ai communities.   while this is mostly due to semantic web applications, we must also credit their ability to cope with taxonomies and part - whole relationships, to handle heterogeneous attributes, and to provide for various automated reasoning services. here   we investigate these features by considering four contributions of ours to application domains wherein ontologies provide key capabilities in system engineering : on - board rolling - stock condition analyzer, intermodal logistic system monitoring, diagnostic decision support system generation, computer - automated design of elevator systems and intelligent computer - automatic design of mechanical circuits. the ultimate goal of the paper is to discuss and compare the results obtained to assess the effectiveness of ontologies in such application domains.
the resurgence of the renormalon@xcite in quantum field theories has been attracting a great deal of attention in the recent study on quantum mechanics and quantum mechanics.   it is expected that the amplitudes of topologically neutral soliton molecules, which are locally composed of ( fractional ) instantons and anti - instantons, can cancel out those arising in non - borel - summable perturbative series in quantum theories under certain conditions on the spacetime manifold. in this paper, we calculate the multi - instanton amplitude of a quantum mechanical system with the sine - gordon potential by explicitly integrating quasi moduli parameters corresponding to separations of instanton - constituents in a semi - classical limit, in comparison with the uniform wkb calculations @xcite. for the configurations with only instantons ( anti - Instantons ), we have unambiguous results without imaginary parts. for configurations containing both instantons as well as instantons  , the results contain ambiguous imaginary parts, which depend on the path of analytic continuation. here, we show explicitly that the imaginary part of the multi-instanton amplitude cancels the large - order behavior of perturbation series around the saddle point without the pair
nonlinear harmonic generation rotational anisotropy ( nhg - ra ) is a non - diffraction based technique for determining the symmetry of the lattice and ordered electronic phases of a crystal.   it is particularly useful because it is sensitive to both lattice @xcite and electronic symmetries and because tensors of arbitrary rank can be probed through successively higher non linear harmonic generation processes in a crystal, which involves recording the intensity of high harmonic light generated from a crystal as it rotates about some crystalline axis. however, several technical challenges associated with maintaining precise optical alignment from a rotating sample have so far precluded such experiments from being performed on small bulk single crystals and under extreme sample environments such as ultra low temperature, high magnetic field or externally imposed strain. in this review,   we describe the design, construction and operation of a novel nhG - ra spectrometer that overcomes all these challenges by using a rotation of the scattering plane as opposed to the sample. our setup opens the way to apply nh g - ra to a broad range of materials, including many strongly correlated electron systems, which are typically only available in small Bulk single crystalline form.. moreover it
the h.e.s.s.   ( high energy stereoscopic system ) instrument is an array of four imaging atmospheric cherenkov telescopes working in stereoscopic mode. to increase its acceptance at low photon energies, the large cherenovkov telescope ( lct ) will have to accept standalone lct triggers. as shown later in section , these triggers are mostly night - sky background triggers and single muon triggers. a second level ( l2 ) trigger board in the camera of the lct   has been built to improve the rejection of accidental interference with the cameras and to allow for the use of topological triggers. here  , we describe the l2 concept and an example l2 trigger algorithm which is based on the n - next - neighbor logic used by the magic collaboration @xcite to detect the pulsed emission from the crab pulsar.
@xcite is a web - based tool for the analysis of recipe data.   it uses a word set of 247 ingredients to construct a factor space, which is then used to extract all the unique terms from the data using a term extractor. in this work   we show how to present the results of the correspondence analysis in an intelligent and friendly way.
the origin of the energy required to power the solar wind, and heat the sun s corona to its multi - million degree temperatures remains an elusive mystery in physics.   one promising mechanism involves the creation of alfvnic waves near the solar surface, which can penetrate upwards through the solar atmosphere with minimal reflection or energy loss. here  , we review the recent observations of spicule oscillations in the solar chromosphere, which have been shown to be generated by efficient mode coupling between magneto - hydrodynamic ( mhd ) waves and periodic transverse motions in aqueous spicules.
we study the electron - electron interaction in the biased bilayer system of biased graphene ( unbiased graphene bilayer ).   we use the standard tight - binding model for the electronic structure @xcite and treat the problem in the metallic regime when the chemical potential lies in the conduction band leading to a topologically non - trivial ring for the fermi surface. by assuming that the electronic gap is sufficiently large so that the valence band is completely filled and inert, we show that the ferromagnetic instability can occur in this system due to the reduced phase space of the ring. also, we calculate the polarization properties of this system and show that they are rather unusual at high frequencies with peculiar friedel oscillations at low frequencies.
tidal dwarf galaxies ( tdgs ) are usually observed during an active star forming stage, allowing tests of star formation criteria and stellar to gas relationships in low gas density environments.   we present results from our giant metrewave radio telescope ( gmrt )  observations of the arp 202 system including at the position of the proposed tdg. using the average radial velocities of ngc2719 and ngc2819a, which are both gas rich, we adopt a distance of 41.3 mpc for these two galaxies and the tdg with a flux density of 12 kpc / arcmin on the scale of @xmath35%. by applying different ` tapers'to the data with varied _ uv _ limits, we show that the tidal tail like extension appears to originate from ngc 2719a with a diffuse object towards its end.    the origin of this extension is likely to be from the interacting parent galaxy(s ), although indisputable criteria remain to be accepted.
we investigate the surface magnetic phase transition of the double - exchange ( de ) model for perovskite manganites by using the schwinger - boson mean - field ( sbmf ) method.   we focus on the behavior of the quantum heisenberg model in low dimensions @xcite satisfying the mermin - wagner theorem. to study the interface magnetism, we use the monte carlo monte van der waals ( mc ) method for the ferromagnetic curie temperature ( @xmath0 ) and tunneling magnetoresistance ( tmr ) junctions. as a result, we find that the surface magnetism of the de model decreases more rapidly than that in the bulk@xcite. however, at interfaces, the surface polarization of the dual - exchange model is not affected by the temperature dependence of the spin polarization at interfaces but rather is due to the temperature - dependent decrease of the magnetoresistace ratio ( mr ) at the interface.
we investigate the existence of gap solitons in harmonic superlattices created on top of the usual bragg gratings in fibers or waveguides with the intrinsic kerr nonlinearity.   we first give our mathematical model of the supergrating and analyze the bandgap structure in the model, using its dispersion relation, using a non - trivial extension of the classical spectral theory for the math of the system s absorption spectrum (  ). as a result  , it is shown that the solution has periodic potentials in one spatial dimension, i.e., the fiber or waveguide with the bragg reflectivity gradually varying along the fiber / waveguide. to find the gaps in the spectrum, we use the averaging method, which assumes that the soliton amounts to a slowly varying envelope of thesupergrating s bloch function(s ). by applying this approximation to the theoretical model,   the results show that there are two types of gaps, namely, the narrow and the narrow ones, which are formed by the bg - induced dispersion and the continuous bandgap, respectively. at the same time, the wide gap is also found to be
the x - ray emitting gas in clusters of galaxies cools by the emission of energy on a time scale which depends on the temperature and density of the medium.   we present data collected with the instruments onboard the italian - dutch satellite _ bepposax _ for three highly luminous, hot, distant clusters of galaxy clusters with large mass deposition rates in their cores : rxj1347 - 1145, zwicky  3146 ( z3146 ) and abell  2390 ( a2390 ). using data from both the low energy ( lecs ) and medium energy ( mecs ) concetrator spectrometer and a joint analysis with the phoswich detection system ( pds ) data above 10 kev  , we show that it is possible to constrain at a high level of significance the hard tail of the bremsstrahlung emission of the cooling gas in the clusters analyzed in the present study. when a single temperature model is adopted, the temperature corrected from the cooling flow of @xmath13 kev is found to be ~2.5 times higher than the value calculated for the cluster with a cooling flow below 10 keV.
superconducting rings are highly correlated low - dimensional systems and their response to the external perturbations, e.g., applied field, has been an ever - growing research area owing to their rich quantum phase diagram.   recent advancements in experiments enable the realization of the quantum dynamics in materials @xcite and in the cold atom system@xcite in non - equilibrium environment. here   we study the breaking of electron - pairs in superconducting ring along with the measurement of their persistent current by flux - quantization of persistent - current, time average current and pair - correlation function using extended - aharonov - bohm ( ab ) period method. at low enough temperature,   superconductors are condensate of cooper - pairs which are sensitive towards the external electric field. for lower values of attractive interaction, electrons form bcs ( bardeen - cooper - schrieffer ) type of pairing with loosely bound pairs, while increase in attractive interaction results in strong local pairing ( bec - limit ( bose - einsteincondensate))@x = 0.5  kj / cm2/s. this depairing of electrons is analyzed by flux-quantification of
the tracking ultraviolet set - up ( tus ) experiment is the first orbital detector of extreme energy cosmic rays ( eecs ).   it was launched into orbit in april 2016 from the newly built vostochny cosmodrome ( russia ) as part of the scientific payload of the lomonosov satellite ( international designation mvl  300, or 2016 - 026a ). during the first months of operation,   the instrument has been able to observe a total of 1.5  km2 of the celestial sphere with a field of view of 80  km@xmath680  km at sea level and a single channel of 5  km @xmath65  km square. for the first time  , it has been possible to observe cosmic rays with energies above 10  eev, which is three times larger than the coverage of the largest existing experiment, the pierre auger observatory ( auger ), which registered only 146 events above 53  eeev in nearly eight years of operation  @xcite. here   i outline the design of tus and briefly present some of the early results of the on - going analysis of data obtained during
the parkes pulsar timing array ( ppta ) project @xcite aims to observe 20 millisecond pulsars with a timing precision close to 100ns over more than five years.   many phenomena can affect the pulse arrival times at this level of timing precision, but the solar wind is a major contributor at our primary observing frequency of @xmath01400mhz. here   we analyse the effect of the solar winds on the timing of the pulsar s dispersion measures ( dm ) when their lines of sight are close to the sun using data from the wilcox solar observatory and the time - varying pulsar - sun - observatory angle ( tai ) program. in the tai program,   the dm is measured as the integrated electron density along the line of sight to the pulsor at @x Math1@xmath2.5  au from the sun which is fixed at 1au by a spherically symmetric model of the energy density of the interstellar and interplanetary medium. for psr   j1022 + 1001, a pulsar that lies near the ecliptic plane, we find that the mean dm varies by about
the yang - baxter ( yb ) equation is a well - known problem in physics and mathematics.   its solutions are intimately related to exactly solvable models in statistical mechanics and the quantum inverse scattering method. here   we investigate whether there exist also solutions of the yb equation for maps with parameters living on elliptic curves and which are associated to integrable partial differential equations ( pde ). by exploiting the local groups of symmetry transformations of the discrete equations, we show that yb maps can be obtained for any quadrilateral equation with a sufficient @xmath15-parameter symmetry group. however, there exist discrete equations which do not admit any local symmetry group such as the discrete version of the krichever - novikov equation, where the lattice parameters lay on an elliptic curve. from the results of the present work   it is shown that the yab maps are derived from factorization of matrix polynomials and yb16functions using the bcklund - darboux transformation of the solution of the q = x = 0.1 polynomial and y = 1 polynormalization of the eigenvalues of the matrices.
we propose a spatial auditory brain   computer interface ( bci ) application based on the use of moving sound stimuli to create richer and more easily perceived auditory events. in order to test this hypothesis,   a simple five spatial vowel speller task is proposed.   we test and compare the concept with seven healthy subjects by comparing their static and moving sound bci spelling results. using electroencephalography ( eeg ) signals recorded by a g.mobilab+ eeg amplifier, we show that the accuracy of the @xmath4  ms long spatial unimodal ( auditory ) stimuli presented from five distinct virtual spatial locations was significantly higher than that of the static sound stimuli for spelling the japanese vowels _ a, i, u, e, o_, represented in _   hirigana_. the results of the online eeg bci experiments were compared with those of the real - time recordings of the brain activity recorded by the same electrodes at the following head locations :@xmathsahara, tara, university of tsukuba, japan. during the online bci experiment, the eeg signals were captured with eight active dry electrodes connected to a
a matrix - continued - fraction algorithm is proposed for the calculation of the energy eigenvalues of the rational potentials of the schrdinger equation.   the proposed method is based on an expansion of the eigenfunctions into complete sets, which are then used to calculate the asymptotic expansions for the energies of the potentials : @xmath1, where the hamiltonian is the potential in equation and the real parameters are arbitrary positive integers and real parameters such that the potential is a rational function of the form :@xmath2 with values of 0.1, 0.2, 0% and 0.5% for the nth, nth and nth/nth potentials in equation, respectively. by applying this method to the potential : @xcite, it is shown that the results obtained for the non - polynomial potentials ( i.e., the nested potentials and the polynomials ) in equation are found to be equivalent to those obtained from the previous methods. moreover, the numerical accuracy of the proposed approach increases as the energy levels increase.
gravitational waves ( gw ) are gravitational waves that travel across otherwise flat empty space at the speed of light, and have two independent and transverse polarisation amplitudes, often denoted @xmath5 and@xmath6, respectively.   the existence of gws poses of course the experimental challenge to _ measure _ them. in this article  , we review the history of the search for gravitational waves in space and time, and discuss the current state of the art in the field, with a focus on the development of new generation gravitational wave detectors.
we study the response of the electromagnetic field to the combined effect of plasma screening and curved space - time in the vicinity of a neutron star.   we compute general - relativistic solutions in the force - free approximation for the maxwell equations in the form of monopole monopole magnetospheres with respect to the magnetic field induced by the screening of the plasma and the curvature of space- and frame - time. as a starting point  , we solve the time - dependent maxwell equation in spherical coordinates using the discontinuous galerkin approach.. the results show that the electric field of the magnetosphere is strongly distorted by the presence of a cusp at the light - cylinder in the case of an aligned dipolar magnetic field which leads to a significant distortion of the parallel component of the current density of theagnetic field due to the effects of curvature and frame dragging.
we experimentally realize quantum hall mach - zehnder interferometer which operates far beyond the equilibrium.   the operation of the interferometry is based on allowed intra - edge elastic transitions within the same landau sublevel in the regime of high imbalances between the co - propagating edge states. since the every edge state is definitely connected with the certain landausublevel, the formation of the interference loop can be understood as a splitting and a further reconnection of a single edge state. by using two quantum point contacts ( qpc ) in a proper sequence, an electronic analog of mach -Zehnder   or fabry - perot  @xcite interferometers can be realized. here  , we observe an aharonov - bohm type interference pattern even for low - size quaternary copper interferimeters. this novel interference scheme demonstrates high visibility even at millivoltimbalances and survives in a wide temperature range.
the cabibbo - kobayashi - maskawa ( ckm ) model of cp - violation is widely accepted as the standard model for particle physics.   however, it is not clear whether the ckm model provides an adequate description of the real nature of cp-violation. in this letter   we study implications of a model in which spontaneous cp - symmetry is broken spontaneously in the minimal supramolecular supersymmetric standard model ( mssm ) and consider the effects of this model on observable cp - violating effects in nonleptonic b - decays. by combining experimental data with b - decay phenomenology  , we show that the characteristic values of the angles of the unitarity triangle formed by the two higgs doublets in the nmssm are significantly different from their standard model counterparts.
laponite clays in aqueous suspensions exhibit a spontaneous ergodicity - breaking phase transition from free - flowing liquids to non - equilibrium, kinetically arrested states such as gels and glasses at low concentrations ( @xmath1 ) @xcite.   the dispersion kinetics of laponite clay under different experimental conditions is investigated using ultrasound attenuation spectroscopy ( uas ) and atomic force microscopy ( afm ). for the first time  , we show that the particle size distribution ( psd ) of clay tactoids in liquid to soft solid transitions with increasing age is estimated using uas data obtained from the absorption spectrum of ultrasound attenuated light scattering in a concentration range ( @Xmath4 w / v ) where the suspensions spontaneously show liquid- to soft - solid transitions. by combining the results of uas and afm experiments, we find that the average platelet sizes of both laponites and na - montmorillonites in aaqueous suspensions are significantly larger than those of the control samples.. the average particle sizes of the two types of particles in the liquid phase are found to be approximately 1.5 - 2.5 nm in diameter and
the classical theory of dispersion in a crystalline solid has a long and noble history.   although the main features of the phenomenon can be described by treating matter as a continuum characterized by macroscopic quantities such as the electric and magnetic polarizations, it is clear that a truly fundamental theory has to be based on a microscopic model of matter. in the present paper   we are going to prove that, on the contrary, a deeper analysis of the behavior of a system of infinitely many charged particles, subject to linear restoring forces towards their equilibrium positions at the sites of a regular lattice, and interacting with each other through the retarded electromagnetic fields, reveals important properties of this fundamental dynamical system which have been for many decades completely overlooked.
the origin of ultra - high energy cosmic rays remains a fundamental and unsolved problem in astroparticle physics.   promising clues could be provided by the associated high energy neutrinos since they would neither interact with intergalactic or interstellar media nor be deflected by the magnetic fields. in this paper, we investigate the shower properties by simulations. equipped with the knowledge of the @xmath1 induced air shower, we are able to calculate the induced geosynchrotron radiation.
we analyze the @xmath3 transition in sm4 by calculating various related parameters like branching ratio, forward - backward asymmetry, baryon polarization as well as double lepton polarization asymmetries. here, we use all involved twelve form factors recently calculated in full qcd @xcite.   this work is an extension of the previous works where the two form factors calculated within heavy quark effective theory ( hqet ) are used. to study the decay of the fourth family quarks in the loop level semileptonic weak transitions of the heavy baryons containing single heavy quink to light baryrons induced by the flavor changing neutral currents ( fcnc ), we calculate the effects of the four fourth generation quarks on the decay rate, branching ratio and other parameters. for each of these parameters,   the results show that the sensitivity of physical observables to them increases with the number of generations of the quarks and the strength of the decay.
the influence of model parameters like the inelastic cross - sections or the elasticity on the average value of  and, consequently, on the mean logarithmic mass derived from it is investigated.   the aim of the investigations is to perhaps resolve the discrepancies in @xmath4 reported by the simulations of the air shower simulation program corsika ( heck 1998 ) and the high - energy interaction model qgsjet ( kalmykov 1997 ) with the experimental data. for the first time  , the influence of the model parameters on the results of the experiments is studied using a phenomenological model, the. the result shows that the model predicts a too small value of @x math4, which is consistent with results from experiments measuring particle distributions at ground level but disagrees with results obtained from experiments investigating the longitudinal development of the nuclear cascade in the atmosphere. as a result, the model predictions are interpreted as being based on an overestimation of the primary energy of the shower particles.
we present a new set of renormalizable lorentz symmetry violation ( lv ) operators for quantum gravity ( qed ) in the ultraviolet.   these operators are modeled by coupling the standard model fields to new lv tensor fields that have non - zero vacuum expectation values. using the uhecr constraints, we show that the cpt odd dimension five kinetic terms for qed coupled to a non -zero background vector can be used to constrain the lv correction to the energy of the reaction with respect to the mass of the particles in the reaction. as a function of the particle mass,   the most important lv terms are the ones that are proportional to the size of the interaction between the two particles and the minimum value of the threshold lv term. when the ratio of the largest to the smallest of the interactions is equal to 1.5, the most significant lv effects are due to the larger the interaction with the background particle. at the same time, the smaller the interaction volume, the more likely it is that the magnitude of the effect will be proportional to its small size. from these results  , we find that the full set of dimension five and six cpt even operators
we report the discovery of two new hot jupiters by using data from the two - wheeled _ kepler _ k2 mission.   the first system is a neptune - sized planet with a period of @xmath10 42 d ( k2 - 30b ), and the second one is a large exoplanet with a radius of ~3.0 cm2 ( K2 - 34b ).    both of these systems were selected as strong jovian planetary candidates based on their strong observational signatures and the presence of significant periodic signals in the light curve at 4.1 and 3.0 days after the transiting of their host stars. for the first time, we have obtained the high resolution spectra and radial velocities of both of the systems using the harps, feros and coralie spectrographs. to obtain the mass and radius of the planets, we performed a joint analysis of the photometric data from k2 s campaigns 4 and 5, using the k2 photometry and the transmission spectroscopy data from @xcite. while the bulk densities of the two systems were found to be similar to those of jupiter, the radial vel
optical traps or tweezers used to manipulate microscopic objects without any mechanical contact have become a major tool in biological research over the last thirty years.   the ability to trap particles using laser light was discovered by arthur ashkin in 1970 and has been extended to study the properties of cells by observing their deformation. as an analytical method, ray - optics ( ro )   remains a difficult approach for calculating the forces on more complex cell shapes like bovine red blood cells ( rbc ) bi - concave discoid shape and deformable cells. here  , we present a dynamic ray - tracing ( drt ) approach to calculate the optical forces induced by a single - beam gradient laser on chinese hamster ovary ( cho ) cells using a high - throughput optical stretcher that uses two counterpropagating diverging laser beams to trap cells individually along the aligned laser beam axis. with the help of a dynamic model based on the governing optical equations, we show that the local optical force distribution and total trapping forces can change significantly with cell deformation under the influence of external flows and thus the local force distribution is different from that observed in the ro technique.. the effect of cell de
we investigate the effects of deformation effects on the properties of the deformed nucleon embedded in light, medium  heavy and heavy nuclei.   the effects are introduced by the distortion of the profile function of the chiral field under the action of the external field ( which parameterizes the baryonic density within a given nucleus ). for axially symmetric few  skyrmion systems with baryon number larger than one, the results show that the effective mass of the solitons in the medium is reduced by about @xmath2 for the center of the heavy nucleus where the density is constant, but not for the light or medium  light nuclei where the densities are constant. for non - spherical solutions of the field equations, the changes in the nucleon shape are investigated by letting theucleon deform under the strong interactions with another nucleon. to obtain the ground state,   it is necessary to deform the model of the skyrme model so that the system is non - spherically symmetric, i.e. the soliton is not bound to the solution of the model within the finite nuclei as considered in the previous work   @xcite.
ship bow waves exhibit both large and small scale features.   the most prominent small scale feature is the bow wave crest formation of thin overturning sheets which break up into spray. re and we scale effects are large such that replication of full scale phenomena of the smaller scale features of ship bow waves is difficult even with large models. herein, flows around a wedge - shaped bow are numerically simulated with the aim of investigating the wave breaking mechanism and small Scale features of boat bow waves.
the susceptible - infected - susceptible ( sis ) household model is one of the basic themes in mathematical epidemiology.   it is an idealization of the spread and persistance of an infection in a population, where each individual is either susceptible, or infected, and each one is coupled to a certain number of other agents. in this idealization,   individuals are equally coupled to all of the others in a large population. in the last section of this paper   we give numerical results on a model which interpolates between the two cases. for the first case, we use the self - consistent field technique, which is based on the assumption that each household is acted on by an average force of infection from outside, and for the second case we do numerical simulations for finite populations where the random - mixing assumption is not valid. as in the theory of magnetism, we find that the self-consistent field assumption is remarkably accurate in situations where we consider a population partioned into households.
the black hole at the centre of a galaxy bulge plays a major role in determining the final stellar mass of the galaxy.   the process by which this occurs is known as cosmic feedback and it takes place through an interaction between the energy and radiation generated by accretion onto the massive black hole and the gas in the host galaxy, either through a wind generated close to the quasar which then flows through the galaxy pushing the gas out, or to dust in the gas, as expected for the interstellar medium of a star - forming galaxy. here   we review the processes involved in the feedback process and discuss the effects of the accretion of energy and momentum from the growth of the central black hole on its host galaxy.
the gw  vir stars constitute a class of pulsating stars descending from post - asymptotic giant branch ( post - agb ) evolution.   they exhibit low - amplitude multiperiodic luminosity variations caused by low degree, intermediate - order nonradial @xmath0-mode oscillations. the chemical composition of the envelope of these stars is critical for the determination of their stability and the temperature of the blue edge drawn for this class is directly dependent on the quantity of carbon and oxygen present in their envelope. here   we discuss here representative calculations showing the effects of the interaction between diffusion and mass loss on the position of the red edge of gw “ vir” stars. using a improved version of the evolutionary code based on a finite element method introduced in @xcite to model the effect of diffusion and masses loss on each other s position, we show that the positions of the two interactions are not significantly different. however, the values of the number of he - dominated atmosphere white dwarfs in the spectrum of the @xmath5pg  1159 transition objects are significantly lower than those of the wild - rayet central stars of planetary nebula ( 
we present a geometric construction of the group structure of hyperelliptic jacobians on @xmath0, a billiard algebra, by using billiard dynamics.   we show that it is possible to obtain such a constructions in higher genera by using the double reflection theorem and some other billiard constructions. here  , we also give an arbitrary - dimensional generalization of the darboux theorem obtained in @xcite.
the sum of fan diagrams of the pomeron - nucleon coupling in the reggeon field theory is widely used to sum all fans of the ha interaction at high energies.   this equation neglects the obvious limitation that the nucleus is finite, so that the number of splittings in fans is restricted and it is not clear how this restriction affects the resulting amplitude. here   we use the schwimmer formula for infinite nuclei as a tool to study this problem. by taking into account that the momenta transferred to the nucleus   are small one gets for the ha amplitude at given rapidity @xmath0 and fixed impact parameter@xmath1 ( b)=. , which is a constant value at very high energies, implying that at such energies the nucleus behaves like a ( grey ) disk, which more or less agrees with the later more sophisticated treatments.
@xmath0 crystal with metallic behavior immersed in distilled water shows an insulating behavior, similar to that observed in @xmath1.   the charge compensation by the intercalation of the oxonium ions leads to the change in co valence from +3.59 to + 3.50 when the sample of the @x Math0 crystal is immersed in aqueous solution of distilled water for 48 hours and the temperature is ~5 k. the physical properties are similar to those of the hydrated sodium cobalt oxide bilayer - hydrate @x math2, but the temperature dependence of the resistivity is different in the two cases.    the in - plane and out - plane resistivities of the samples were measured by standard four probe method before their immersion in purified distilled water. it is found that the increase in the temperature leads to a decrease in the thermopower, hall coefficient and thermal conductivity at x=0.5. the results suggest that the charge ordering of the na+ and co ions is not due to the presence of oxygen vacancies in the superconducting hydrates.
we investigate few ultracold atoms in one dimensional optical lattices.   the atoms are localized in a one dimensional lattice parallel to an optical nanofiber, where the trapping volumes are at most one and the filling factor is half. for the first time   we show that the electronic excitations can be transferred among atoms at different sites and delocalized in the lattice due to electrostatic interactions, i.e. resonance dipole - dipole interactions. by exploiting the lattICE symmetry,   an electronic excitation can be represented as a wave that propagates in the laser beam - induced lattice, which is a quasi - particle termed an exciton ( e.g. a superradiant or metastable exciton ). from the quantum phase transition of the mott insulator phase of the optical lattice with the help of counter propagating laser beams, we find that the lifetime of the excitons is very short, ranging from a few seconds to a few hours, and the emission patterns into free space are similar to those observed in molecular crystals.
high harmonic transient grating spectroscopy ( hhg ) is a new experimental technique for probing molecular dynamics.   it is based on the high - order harmonic generation process, which occurs when a molecule is submitted to a strong probe laser field and excites in the first optically - allowed electronic state @xmath2b@xmath0 close to the first dissociation limit. here   we show that the diffracted signal from the excitation grating directly reflects the vibrational dynamics of the first excited diabatic state around the conical intersection. by reducing the point group symmetry to c@x Math4,   the 1@x math2a@x maths5 and 1@ xmath2 b@xMath0 states become the 1#@x mathematics2a and 2#@Xmath2a states respectively that are vibronically coupled.. this strong coupling results in a high density of states ( 0.754 levels/@x mathematical6 ) @xcite and leads to the loss of both the electronic and vibration / rotation signatures.    simulations based on trajectory surface hopping ( tsh ) reveal that the oscillations of the femtosecond transient with respect to
the advent of precision cosmology with measurements of the cosmic microwave background ( cmb ) radiation has brought a new focus on the physics of the @xmath0 universe.   the connection between two fossil relics of the early universe  the cmb fluctuations and galaxies  offers the possibility for improved understanding of both as well as tighter constraints on cosmological parameters. in this lecture series,   we present an overview of the physics that underlies structure formation starting after the inflationary epoch, going through recombination, and extending to the present day. from the perspective of Cosmological perturbation theory, these lectures may suggest how, with minor simplification, it can be integrated into a treatment of large scale structure.
we introduce a novel system of well - defined coupled macrospins in which the number of moments @xmath0 is fixed to be odd, which, as we will show, forces the system to possess a frustrated topological soliton defect@xcite in its ground state ( gs ) and form an approximate realization of a magnetic mbius loop.   the curvature of the ring imposes chirality under the application of a rotating constant - amplitude magnetic field, and we use numerical simulations to show how this allows for a soliton to be driven around the system. with experimental realization in mind,   we make various assumptions appropriate for patterned nanomagnets to build the model and further test for robustness against quenched disorder ( qd ). using the system as a multiturn counter, we demonstrate that the system can be used to perform reliable and repeatable operations, including the propagation of a charge soliton along a conduit between two ground state ordered phases.
tilings are studied by mathematicians, physicists and material scientists. to a physicist,   tilings are used as models for ordered materials, such as crystals and quasicrystals.   the most interesting questions are about the physical properties of the material being modeled. in this paper  , we review the construction of a tiling space @xmath2 and explain the connection between m1 and p3, relying on @xcite for details and proofs.
we have followed the dynamical evolution of star clusters by performing @xmath0-body simulations, in order to catch the moment of binary formation. upon spotting the first binary,   we have then analyzed in detail how this binary formed, with how many other stars involved, and in what kind of step - by - step process.   our results show that the binaries are formed through three - body encounters, which are driven by two - body relaxation and a high stellar density region at the cluster center. after the first encounter, the core of the cluster undergoes core collapse, leading to the formation of a high - molecular - weight binary. during the next few years, the number of binaries increases gradually, until they reach the limit of the time required to harden the binary.
the higher order bose - einstein correlation ( bec ) of the three - charged particles @xcite has been studied by alt et al. in this paper   we derive a modefied theoretical formula for 3-particle bec introducing the degree of coherence parameter into eq.   (  ). using this formula, we analyse the data of the na44 collaboration experiment using gaussian source distributions of radii and the coulomb wave functions of the respective 2-body collisions. from these data, we can infer the size of the interaction region and therefore estimate the energy densities reached in high energy collisions. to get more precise sizes of the interactions, we have to take into account the final state interactions among the charged particles@xcite. here, we investigate whether or not there is a physical connection between our study and the core - halo model @xaite.
the vimos integral field unit ( ifu ) is a new instrument that allows to obtain one spectrum for each resolution element of its field of view, thanks to a square array of microlenses, each one coupled to an optical fiber.   it is currently being used in the study of medium and high - z clusters, where the number of interlopers is roughly 90% of all the field objects. as a result  , it is possible to obtain spectra for all the objects in the field at once, making it much more efficient than a multi - detector telescope ( mos ) in very crowded fields, where complete sampling is required. here   we review the current state of the art in data reduction and analysis of ifu data, focusing on the use of the european network of vimos ifu instruments, with the purpose of providing the astronomical community with powerful 3d data analysis tools.
experiments at rhic and lhc indicate that the quark - gluon plasma is an almost perfect fluid where viscous effects are small @xcite.   in contrast, at low temperatures and nonzero baryon chemical potentials in the hadron gas phase, viscosity may be considerably more pronounced @xmath1. here   we study the propagation of linear and nonlinear waves in relativistic fluids described by ( a simplified set of ) of the 2nd order conformal is equations with the help of the well established reductive perturbation method @xaite. using the well - known navier - stokes theory, we show how to obtain the linear wave equation which contains the dissipative and relaxation terms for the two modes of the dispersion relation between the shear viscolysis coefficients and the relaxation time coefficient. understanding the relaxation effects in the linear modes proved to be a useful guide to approach the same question in the case of nonlinear perturbations.
the numerical evolution of rotating neutron stars in full general relativity has been the focus of many research groups in recent years.   so far, these studies have been limited to initially non - rotating stars. however, the numerical investigation of many interesting applications, such as the rotational evolution of proto - neutron stars and merged neutron stars or the simulation of gravitational radiation from unstable pulsation modes, requires the ability of accurate long - term evolutions of rapidly rotating stars in general relativity. here   we present a 2-d ( axisymmetric ) code for the numerical integration of the general relativistic hydrodynamic equations of rotating protoneutron stars in the approximation of a static spacetime. using high - resolution shock - capturing ( hrsc ) finite - difference schemes  , we show that the code is able to accurately simulate the hydrodynamical evolution of a rapidly rotating newly - born neutron star from a slowly - rotating pulsar to a crab - like slowly - moving pulsar within about a year after its formation.    the code can be freely available at http://www.gravity.phys.uwm.edu/code/rns.
the balitsky, fadin, kuraev and lipatov ( bfkl ) equation is used to describe the energy dependence of certain high energy hard processes.   the purpose of the present paper is to study two related questions, the probability of producing an unusually large number of particles in an onium - onium collision and the nature of gluon ( dipole ) evolution when dipole densities become so dense that saturation effects due to dipole - dipole interactions become important. for the first question   it is shown that at a given energy density of the onium there is a very high multiplicity tail of particle production which increases with increasing dipole density. at even higher values of energy   one expects parton densities to become so large that the whole perturbative qcd picture breaks down leading to a new regime of weak coupling but high density non - perturbation qcd.
the formation of myelins, the long - lived spherical multilamellae that form when bilayers of dimyristoyl phosphatidylcholine are dissolved in water, has been a mystery since their discovery more than 150 years ago.   we have investigated the effect of water permeation on our model of myelin formation and show that it can be favorable because its cylindrical form results in a larger bilayer repeat spacing ( i.e., separation between bilayers ) and hence lower inter - bilayer repulsion than flat multilamesllae. to explain the myelin shape transition, we postulate that the number of bilayers is unchanged during the shape transition ; the bilayers can exchange materials freely to achieve quasi - equilibrium@xcite ; and the free energy includes a curvature energy favoring flat bilayers @xcite and a repulsion between bil layers@xcites.    we also show that the structure of the monomeric myelin complex is preserved during the resorption phase of the disk - to - myelin shaped transition.
the large hadron collider at cern will have to face a challenging environment after the accelerator upgrade to high - luminosity running ( hl - lhc ), that is currently being planned to start in 2022.   calorimeters designed for an adequate performance through the years of running at the lhC may need to be partially upgraded, to withstand the increased exposure levels expected at the new hl-lhc. this paper describes an innovative light collection geometry that minimises the mechanical processing complexity of a sampling calorimeter cell using wavelength - shifting ( wls ) fibres as a scintillating medium.    the geometry consists of a sampler cell made of passive absorber layers interleaved with layers of an active medium made of inorganic scintillation crystals.. the simplicity of the design minimises its mechanical processing complex, compared to other geometries with grooves or holes machined through the stack. 	 the results show that the proposed geometry is working for cerium fluoride ( cef@xmath0 )  @xcite scintilled crystals, which are photo - luminescent in the range of wavelengths of the cephalic emission
we introduce pseudocubical objects with pseudoconnections, obtained from the brown - higgins structure of a cubical object with connections, which are derived functors in the context of the theory of tierney and vogel.   we show that these objects possess pseudodegeneracies and pseudocon Connections and that they are naturally isomorphic to the cotriple derived functor of barr - beck if there is an @xmath5-augmented pseudosimplicial object in @x Math1 that realizes the given projective class @x math2.. we also show that for every @xMath5 from@xmath1 a @x maths2-projective resolution can be constructed, which is an augmented pseudos implicative object in@x mathematics1 and which for a given @Xmath5 is unique up to a presimplicial homotopy ( according to the comparison theorem for @xmatrix- Projective resolutions ).
single - photon sources are of utmost importance in optical quantum information processing as well as in quantum optics.   while the indistinguishability of the produced photons is not high enough for the majority of the practical applications, the probabilistic nature of the pair generation complicates the creation of a deterministic or periodic single - photon source based on correlated photon pair generation in nonlinear optical media such as spontaneous parametric down - conversion ( spdc ) in bulk crystals and waveguides. in this paper   we provide a detailed statistical description which is applicable to all known kinds of multiplexed sources, aiming at the maximization of single - particle probabilities under realistic experimental conditions taking into account the possible loss mechanisms. using the proposed scheme, we analyze various kinds of several multiplexing schemes, namely an ideal system, a spatial multiplexer, a storage cavity based multiplexers, and a bulk time multiplexes, and propose a novel bulk timeMultiplexing scheme with a multistage delay line that can be realized on a silicon - on - insulator photonic integrated circuit. according to the analysis,   the performance of this scheme is the best considering state - of - art experimental technology,
the morphology and star - formation rate of the ngc 4065 group of galaxies in the coma supercluster have been studied with the giant metrewave radio telescope ( gmrt ) in the indian polar mode.   this group is a unique laboratory for studying ram pressure stripping as we have two independent means of measuring the density of the intergalactic gas in this system which also contains an edge - on, late - type disk ( sc ) galaxy ( ugc 07049 ). using the vla d - array data from the arecibo project, we show that the density profile of the hi rich group members differs from that of the field @xcite. at the highest density region of @xmath5 the fraction of intermediate type ( s0 ) galaxies begins to increase while the late -type disk galaxy fraction decreases and the star - creation rate decreases. at lower density regions ( @x Math3 or @xMath4 ) the fraction increases while the elliptical fraction decreases.    these trends continue till @x math7 where the fraction becomes more elliptical and the ratio of intermediate types decreases. here   we find that the behavior of these relations over the separate regimes indicates a
we present a new mechanism for the ejection of the common envelope from a low - mass companion in a short - period black - hole binary : " explosive common - envelope ejection ".   this process involves nuclear rather than orbital energy, which can be highly efficient in ejecting a massive envelope even if the companion is a relatively low- and intermediate - mass star. here  , we show that this mechanism can be used to explain the observed high abundance of hydrogen - rich material in the companion s envelope in the case of compact black -hole binaries associated with long - duration gamma - ray burst ( lgrb ) supernovae.
the mikheyev - smirnov - wolfenstein ( msw ) effect for neutrino oscillations in the sun @xcite is studied.   the msw effect is described by the coupled ordinary differential equation @xmath13 = \left}. the lepton mass matrices of the three generations of neutrinos @x Math1, @x maths0 and@xmath2 are also discussed.
we report on the results of a deep optical imaging survey of the nebular remnants of a sample of northern - sky classical novae using the anglo - australian telescope.   we investigated the images for evidence of extended emission by comparing the nova to two stars taken from the same frame using contour maps of images of each object scaled to the same peak brightness, and by examining the azimuthally averaged brightness profiles of the novae for which we believe we have detected extended emission. in all cases   there was no evidence of extension of the material observed.
we present a new gauge higgs unification model for the standard model ( sm ) fermion fields.   the model is based on the use of warped extra dimensions, where all fundamental parameters are of the order of the planck scale and the weak scale hierarchy is obtained by an exponential warp factor, which is naturally small provided the higgs field is localized towards the so - called infrared brane. in this article  , we analyze the addition of the lepton sector in the gauge higgens unification scenario with the proper generation of third generation quark and gauge boson masses for the same values of the bulk mass parameters that lead to agreement with precision electroweak data at the one - loop level.
we revisit quantum communications ( qc ) using the theory of geometrically uniform symmetry ( gus ).   we assume that a finite set ( constellation ) of gaussian states has a special form of symmetry, called gus, and generate a gus constellation starting from an arbitrary @xmath0-mode gaussian state through a unitary operator, called the rotation operator. in this context   the most general gaussian transformation is given by a cascade combination of a squeezing, a displacement, and a rotation. for pulse position modulation ( ppm ) we present an application of the theory to the quantum detection for ppm, which requires a non trivial analysis in a multimode hilbert space.
we perform numerical simulations of the formation of cosmic strings using a cubic lattice and a complex gaussian field with long - range correlations, where the strings are taken to lie along the zeros of the field.   we find that the probability of string formation is dramatically reduced by smoothing the initial field in the form of an analytic function for @xmath5, and that the fraction in infinite strings is lattice - free when the field is smoothed to remove lattice effects.
the _ herschel _ multi - tiered extragalactic survey ( hermes ) is a guaranteed time key program on the _ her schel _ space observatory.   it consists of 13 target blank fields at approximately seven different depths ( levels 1 - 7 ) covering a total area of @xmath0380 deg@xmath1 which include a later addition of a wide hermes large - mode survey field ( helms ) observed by spire alone. in this paper   we present a new source detection and photometry method which combines an iterative source detection algorithm starfinder ( sf ) and a de - blended spire photometry ( desphot ) algorithm to extract sources below the nominal confusion limit for most of the hermes fields from the first extensive data release ( dr1 ) of maps and catalogues and all observations except helms released during the second extensive data releases ( dr2 ) of hermes. using the two different source extraction methods ( sussextractor ( sxt ) and starfinder combined with des photographs ), we generate point source catalogues for the dr1 and dr2 data releases. as catalogues are the starting point for understanding the far - infrared / sub
the frozen density embedding ( fde ) method is a popular tool to treat intermolecular interactions in a simple and potentially exact embedding scheme.   it is based on the partitioning of the total electronic density of a system into a set of subsystem densities ( e.g., for two subsystems @xmath0 and@xmath1 : @x Math2 ) and the use of the kohn - sham equations with constrained electron density ( ksced ) from density functional theory ( dft ) @xcite to solve the kinetic and exchange - correlation ( xc ) energies of the noninteracting kinetic energy functional eq.  with respect to one of the subsystem electron densities by keeping the other one fixed and using the expansion of the electron density in terms of ( auxiliary ) khn - sham orbitals @x math8 + \nonumber & & + \int \left(v_{\text{ext}}^{\text{a}}({\mathbf{r}}_1}+\frac{e1}{2}\int\int\frac{\left(\rho_{\ text{a }+\rho{b } }
compton scattering in quasi - spherical accretion flows is thought to be responsible for the x - ray spectra of many accreting compact objects.   the time - dependent photon kinetic and radiative transfer equations and their zeroth and first moments that describe absorption, emission, and spontaneous and induced compton scattering are solved for static and moving media using monte carlo methods, and the system - frame equations that were derived are valid to first order in the system frame and to _ second _ order in @xmath2 and@xmath3, where @x Math2 and @x math3 are the photon energy and the bulk velocity of the electrons in units of the electron mass and temperature, respectively. under the general - relativistic model,   all three independent phase - space coordinates of the photons are taken into account, as well as the spatial coordinate of the excited state of the absorbed photons. by solving the photon kinetic equation and its moments, the time- and energy - dependent effects of the radiation on the density of the particles in the accretion flow   are fully accounted for, with no need for any priori closure relations. a new method for calculating the intensity of compton
optical emission in persistent low mass x - ray binaries ( lmxbs ) is triggered by reprocessing of the powerful, almost eddington limited, x -ray luminosity ( @xmath0 erg s@xmath1 ) in the gas around the compact object.   the spectroscopic features of the weak companion star, on the other hand, are completely swamped by the disc s reprocessed light, with the exception of a few long - period Lmxbs with evolved companions such as cyg x-2 ( @xcite ). to extract dynamical information from the bowen emission in sco x-1, we have used high resolution spectroscopy to detect many narrow high - excitation emission lines, the most prominent associated with niii and ciii at the core of the broad bowen blend. using these lines, we obtained with isis at the wht, we calculated the radial velocities of the narrow bowen lines in the black hole candidate gx339 - 4, detected during the 2002 outburst, which led to a mass function in excess of 5.8   and hence provided the first dynamical proof for a black hole @xaite.
the parametrically driven ginzburg - landau equation (  ) is used to study the localised structure of solitary waves in a variety of nonequilibrium systems.   the parametric driver is the diffusion coefficient, @xmath0, which is chosen to be nonzero for all positive and negative terms but not for the quintic terms. as a minimal generalisation,   we allow for a nonzero diffusion coefficient ; this gives rise to a new phenomenology of localised solutions which includes the multistability of pulses and pulse - front transitions.
the palomar - quest southern sky survey has been in routine observations since september 2009.   the survey covers @xmath51000 square degrees per night, primarily between @x Math625@xmath4 to allow for follow up from both hemispheres. during the survey   we have discovered a deep eclipsing cataclysmic variable ( ( *?????   * rabinowitz et al. 2011a ), an apparent dwarf nova and a star with a spectral type m8 or later secondary.
circulators are important passive nonreciprocal components which are used both in microwave and optical frequency region.   the most popular circulators are based on waveguide and microstrip technology with magnetized ferrite elements @xcite. in this paper, we suggest a graphene circulator with a very simple structure which can be used in thz and infrared frequency region.the circulator consists of graphene nanostrip waveguides connected to a graphene circular resonator with a diameter of 2 nm and a length of 2.5 nm that are placed on a lossless dielectric substrate of silicon and silica with the thickness of 200 nm and 600 nm, with relative permittivity of 11.9 and 2.09, respectively.    the device consists of two kinds of guided surface plasmon polaritons ( spp ) modes, namelly a guide mode and edge mode, which are named after the direction of the eletromagnetic field in that mode, once it is concentrated in the center of the geraphene ribbon. using numerical simulations by the commercial software comsol@xcite, we have used the following parameters of the graphene conductivity tensor for the design of the circulator
the authors present two families of relativistic solutions of infinite thin disks with halo.   the disks are obtained from solutions of the einstein equations for an axially symmetric conformastatic spacetime in which the metric tensor is characterized only by one metric function. by introducing a finite discontinuity on the first derivatives of the metrics tensor,   solutions with a singularity of the delta function type are obtained, so describing thin disks. by using the solution to laplace equation in cylindrical coordinates   we find infinite disk - like solutions, and by using it in oblate spheroidal coordinates we find finite disks. in both cases   particular solutions with energy densities and pressures well behaved everywhere are obtained. also, we show that the masses of de disks and the haloes are finite. finally we solve the geodesic equation for circular orbits in the plane of the disk.
the scaling of the scaling exponents of domains after a quenching in the striped phase of a bidimensional isotropic eight vertex model is studied.   the scales are obtained by studying the amount of interfaces and the shrinking time of a  ball " of one phase plunged into a sea of a different phase. for the single - spin - flip or spin - exchange dynamics we find an anisotropic behavior of the scaled correlation functions as well.
v838 monocerotis is an eruptive variable star that underwent a nova - like event in early 2002 @xcite.   the eruption was unlike classical novae in that the effective temperature of the object dropped and the spectral type evolved into a very late m   l type@xcite, with a peak intensity of @xmath3. here   we use the palomar testbed interferometer ( pti ) to resolve the near infrared ( @x Math22 m ) emission from v838 Mon and measure its apparent angular diameter. for the first time  , we have measured the apparent angular diameters of the visible and near infrared emission from this star at the milli - arcsecond scale using a new interferometric technique.. the apparent size of the apparent center of the light echo appears to move on the sky ; this is consistent with a circumstellar dust model and would appear to favor the interstellar interpretation.
on march 11, 2011, reactors at the fukushima dai - ichi nuclear power plant in japan were shut down following a 9.0 magnitude earthquake and a 14-m tsunami.   fires, explosions and possible partial core meltdowns released radioactive fission products into the atmosphere. to assess the impact of the accident on our physics program that relies on ultra - low radioactive background detectors, we began collecting airborne particle samples and monitoring for fissions products on march 17, 2011. over 62 d, 38 air filters were collected from the roof of phillips hall at the university of north carolina at chapel hill ( 35@xmath155n, 79@x Math12 w, 150 m elevation ) and assayed by high - purity germanium ( hpge ) detectors using a marinelli beaker with a very low background. during the first 62 d following the earthquake, we detected ^131,132^i, ^134,137^cs, ^132^te and ^133^xe in the united states, europe, western japan, russia and france as well as rainwater in the west coast of the united States. since the first detection of ^131^i
collective decision making systems ( cdm ) are distributed and decentralized systems that rely on self - organizations to achieve a specific goal.   they usually involve amplification or positive feedback as well as damping or negative feedback along with several cooperative - competitive interactions to evolve and navigate towards its desired state. due to the non - linearity involved and a great number of microscopic details, these systems are usually difficult to analyze and establishing direct analytical connection between the microscopic and macroscopic model seems infeasible for most of the practical systems. in this project   we have taken a cue from the work of biancalani _ et al_ @xcite and expanded the model following the method described in hamann    et al.    here we have used a larger neighbourhood size and majority rule to determine the transition in an agent s decision. at last an analytic approach   is used to justify the probabilities and link them to the macroscopically behaviour of the trajectory. it s seen that hyper - geometric distribution is applicable to the cdm system like the one investigated here.
the range and complexity of datasets and resources published to the virtual observatory ( vo ) is rapidly increasing.   these resources are heterogeneous - and are published through various standard interfaces allowing access to images, catalogues, spectra, transient event data, tool interfaces and so on. with the advent of these many resources available through the vo,   an emerging challenge is how to offer the astronomer a reliable and usable means to search, retrieve and visualise the relevant data and resources to meet the needs of their particular science problem. in april 2008, the uk astrogrid vo project made the first public release of the vo desktop suite of applications which consists of several interlinked tools including the voexplorer resource browser, file explorer, task runner and query builder. here   we illustrate the use of the astro grid software to tackle a typical multi wavelength science case involving x - ray selected clusters of galaxies at different levels of complexity and show how search and correlation results may be saved to remote or local storage as well as passed to any suitably enabled vo tool for further visualisation and analysis.
fluidized beds are widely used in chemical industries since early 19 s, and they have been studied from technological point of views.   recently the present authors have proposed a numerical model of fluidized beds, where hydrodynamic interaction among particles is calculated with reliable accuracy. in this paper  , we will present the results of our systematic simulations and behaviors on statistical quantities obtained from the simulations. for simplicity, we only consider the cases of monodispersed spherical particles. to simulate the dynamics of granular particles in fluid flows,   we use dimensionless quantities with the aid of the particle radius and the sedimentation velocity of a particle. at low flow rate, the system is in the fixed phase where particles rest on the bottom. when the flow rate exceeds the critical value, particles start moving into the fluidized phase, which contains sub phases, for instance, the homogeneous phase, the bubblingphase, the channeling phase, etc. by using the hole theory for simple liquids, we show that the transition of fluidization and the existence of two fluidized phases can be explained by the presence of equilibrium correspondences.
we present analysis of strong uv emission associated with tidal tails in four major galaxy interactions, including the ngc  7769/71, ngc 5713/19, arp  295, and ngc - 520 systems.   we show that tidal tails are ejected from gas - rich galaxies during strong interactions, and that they may have formed new  tidal dwarf galaxies " ( tdgs ) by self - gravitation of gas condensations from the tidal tails into new star clusters and associations.
in supersymmetry, the electroweak scale of order 100 gev is a stable bridge between the grand unification / planck scale and the quantum gravity scale.   the proton - collider lhc and the @xmath2 linear collider ilc, now in the design phase, will provide us with a comprehensive and high - precision picture of supersymmetric physics at the electro weaken scale, defining a solid platform for the reconstruction of the fundamental physics scenario near the planck Scale.    this procedure is described for three characteristic examples in this report   minimal supergravity, a left - right symmetric extension, and a string effective theory.
the study of the equal time cross correlations between stocks has attracted much interest in the past.   it is of interest to investigate the time dependent cross correlations because they contain information about the way how the prices influence each other, which are the dominant stocks and to what extent this dominance is reflected in the price changes under the conditions of an efficient market. in this article   we study the time - dependent cross correlation functions of the returns of different stocks taken from the new york stock exchange ( nyse ) over the time period from 01.12.1997 to 09.03.1998. for many cases the maximum of the correlation as a function of time is not at zero but shifted, meaning that there exists some " pulling " effect between the companies, i.e., _ one of them influences the price behaviour of the others. however, this effect can not be strong and the shift should be small, otherwise the effect could be utilized for arbitrage purposes, which is excluded from an efficient markets. in fact the results agree with those of @xcite, who studied weakly returns, and they found significant cross - correlations on the weakly scale.
non - linear piezoelectricity in zinc - blende ( zb ) iii - v semiconductors and nanostructures has been a topic of intense debate over the last few years.   the existence of non - negligible second - order effects in gaas and inas was first proposed by bester, migliorato and beya - wakata in the context of linear - response density functional theory ( dft ) and then revisited semi - empirically using harrison s bond orbital model and a strain - dependent kleinman parameter. here   we show that this non - linearity can be explained by the well - established relation between the dynamics of wannier function centers and electric polarization. for the family of zbiii - v materials studied here,   both the linear and nonlinear contributions to the pz coefficients are investigated separately, as well as the influence of volume effects on the evolution of the coefficients for the different compounds. while trends in the coefficients of @xmath3 and@xmath4 alone are difficult to extract, we find that the latter tend to decrease and to increase, respectively, with increasing unit cell volume. when charge redistribution and internal
the diffusion of particles in a narrow channel is a subject that has brought attention in the last decade because of its ubiquity in nature.   examples of this can be found within blood vessels, protein channels in cell membranes, zeolites and nano  porous materials such as @xcite. theoretical description of these systems have been proposed using the fick   jacobs equation. in this paper   we propose a generalization of the fokker - planck equation to take into account the effects of a repulsive interaction among particles. for this purpose, we derive a non - linear fick - jacbs equation for particles with repulsive or attractive interactions based on the expression of the particle current derived from monte carlo simulations. by applying this new equation to the case of identical particles interacting through a hard  core potential, we obtain a novel fick-jacobs equations for the description of diffusion along a narrow tube of variable transverse area.
the existence of a liquid phase of molecular para - hydrogen ( p - h@xmath0  ) at temperatures lower than 6k@xcite is believed to depend on the difficulty for the system to go over the nucleation energy barrier in a time comparable to the lifetime of the clusters themselves.   the determination of such an energy barrier depends on the knowledge of a number of physical parameters, but in particular on the solid  liquid interface energy. in this paper   we introduce a shadow wave function optimized and parametrized variational monte carlo method for the description of inhomogeneous phases of @xmath4he with large numbers of particles using shadow wave functions ( swf ) based on x- and y - ray diffraction ( xrd ) simulations. by means of this method   it is possible to study the existence of liquid  solid interfaces in both the crystalline and the disordered phase of a quantum system with the same translationally invariant form. from the theoretical point of view   our results show that the transition temperature of the liquid phase is between 0.38k and 0.15k, which is close to the predicted value of the interface energy of solid@xc
the quadratic gravitational lagrangian, when formulated in a form which includes both the metric and the torsion as dynamical variables, can explain the galactic rotation curves and the amount of intergalactic gravitational lensings.   we postulate that if nature is going to make use of the einstein - hilbert lagrangia, matter will be endowed with either one of the following two metrics : regular matter or primed matter. from a spherically symmetric source,   regular matter will interact only with regular matter gravitationally, and primed matter will interactions only with primordial matter gravitations. for a homogeneous and isotropic universe, there is no need for either metric, and the universe can accommodate acceleration during its expansion if it evolves together with an expanding metric.
the adiabatic error is the fidelity loss between the actual time - evolved state ( the solution of the schrdinger equation ) and the instantaneous ground state, calculated at the final time @xmath0.   it is often assumed that a more slowly varying hamiltonian and/or a longer evolution time should result in higher fidelity or accuracy. here   we perform a comprehensive analysis of this tradeoff for the case of an adiobatic quantum search algorithm, in a closed system setting. using a formal polynomial expansion of the adiabsidic error, we show that the evolution time may exhibit a short-@xmath 0 _ exponential decay, which is hidden in the formal poyleomial expansion.. we show how this short - time exponential decay heralds the correct scaling for the evolution times, avoiding the overestimation that results from the long - time polynomials.    additionally, we propose specific adi ab initio evolution paths ( interpolations ) inspired by a procedure for minimization of time functionals for adi Ab initio Evolution.,we also examine the applicability of the traditional measure of the evolution Time and contrast this to what we obtain from
active galactic nuclei ( agn ) are powerful sources of radiation in a wide spectral range : from @xmath1 rays to radio waves.   they derive their extraordinary luminosities from energy release by matter accreting towards, and falling into, a central supermassive black hole. according to the unified model of agn, their central engine consists of a super massive black hole ( smbh ) surrounded by an accretion disk that radiates in the x - ray band @xcite. here   we discuss the fe k@xmath0 spectrum profile of type 1 agn which can be explained by the emission of relativistic accretion disks around the smbh. moreover, we present some effects which can disturb the profile of the line profile, such as : perturbations in the disk emissivity, absorbtion by warm absorbers and gravitational microlensing.
madeup is an integrated development environment for programmatically generating 3-d models.   its primary purpose is to serve as a platform for teaching computation and algorithmic thinking to young learners of mathematics and computer science. the interface is comprised a text - based code editor and a 3-D canvas that allows users to program their models in a custom but traditional language that supports variables, operators, control structures, and modular abstraction.database url : http://www.madeup.org
thermodynamics forms part of the bedrock of our current understanding of the physical world.   it has remained unchanged despite huge revolutions in physics, such as relativity and quantum theory, and few believe it will ever fail. over time, it has been applied to situations well outside its original domain ; from black holes to quantum engines comprised of only a few qubits. here   we revisit and modify the resource theory framework of thermodynamics as originally put forward in @xcite. in this new context we achieve two main results : first we prove the second law of thermodynamic action, and second, we show that free energy is a relevant quantity for individual quantum systems.
in this paper, we develop a theory of the existence of wrinkled solutions of the incompressible and compressible euler equations in two and higher spatial dimensions.   the approach is based on the analogy with the solution of the isometric embedding of a two - dimensional riemannian manifold into three - dimensional euclidean space given by the nash - kuiper theorem ( @xcite ). to make the link, we derive the equations of a new type of geometric flow and then interpret the consequences of this fluid - geometric duality.
a key challenge in solar information processing is to use data of the photospheric magnetic field to infer the non - potential magnetic energy inherent in the coronal magnetic structure.   this article provides a complete analytical connection between the multifractal formalism and the set of 3d equations that govern the small - scale and large - scale magnetic structure on the sun. by using the wavelet - transform modulus maxima approach of determining the multiscale fourier scaling index from 2d images of the michelson doppler imager ( mdi ),   we show that the size scale of the spectra obtained from the mdi can be used to determine the spatial resolution of the frozen - in field structure arising from the large magnetic reynolds number in the solar photosphere. as the size of the field structure increases, the amplitude of the multiples increases, and the frequency of the fractals decreases. at the same time, the signal - to - noise ratio increases, which is associated with the formation of turbulence in the magnetized plasmas. when these two parameters are not taken into account, the results of the study by @xcite and@xcite suggest that the magnitude of
the shadow corrections in elastic scattering from deuteron are studied in the framework of regge phenomenology.   the new scaling characteristics of scattering from the constituents in the composite systems, having a clear physical interpretation, are established using dynamic equations obtained on the basis of single - time formalism in qft @xcite and the contribution of three - body forces to the total cross - section in the scattering from Deuteron is studied by means of eikonal approximation for high - energy scattering amplitudes.
hard exclusive processes, in which the nucleon remains intact, have emerged in recent years as prime candidates to complement this essentially one dimentional picture.   the simplest exclusive process is the deeply virtual compton scattering ( dvcs ) or exclusive production of real photon, @xmath3. here   we examine the most recent data recorded from the desy@xmath0 collider at hera and their implication on the quarks / gluons imaging of the nucleus @xcite.
electronic coherence is a coherent dynamics in the electronic degrees of freedom ( dof ), as opposed to the expected incoherent hopping dynamics.   2d electronic spectroscopy has been used to measure long - lived oscillations in the fenna - matthews - olson ( fmo ) photosynthetic pigment - protein complex, which reveals the presence of long -lived electronic coherence @xcite. here  , we analyze the dynamics of a closed system pumped by incoherent light and show that the amount of dynamical coherence generated under sunlight pumping is constant, inversely proportional to the exciton energy gap, but decreases if normalized by the linearly growing exciton populations. for very incoherent radiation, which is the case relevant for the natural sunlight, the white - noise model ( wnm ) provides a reliable description of the optical excitation. using the hierarchical equations of motion ( heom )@xcite as a non - perturbative description of both the phonon bath and photon radiation, we further introduce a decay channel, which defines an observation window for the induced exciton dynamics. the drude - lorentz spectral density assumed by the heom differs from the black - body spectrum
the solar irradiance in the herzberg continuum range ( 200220 nm ) is of especial importance for the climate modeling as it directly affects the ozone concentration and stratospheric temperature @xcite.   the proper modeling of the formation of this radiation in the solar atmosphere is a base for the variability modeling and for the irradiance reconstruction to the past. in this paper   we analyze the first measurements of the large yield radiometer ( lyra ) onboard the proba-2 satellite launched on november 2, 2009. up to now lyra has observed several solar eclipses. using the 1d nlte radiative transfer code for solar irradiances ( cosi ), we calculate the clv of the solar brightness and compare them with ones deduced from the eclipse light curves as observed by lyra. at the same time we show that the measured clv provide an important constrains on the uv opacities and the temperature structure of the Solar atmosphere. finally we come up with a model which allows to accurately reproduce the measurements.
we present observations of the nuclei of three nearby, infrared bright seyfert galaxies  ngc  1275, ngc.   4151, and ngc - 7469  taken with the keck 10-m telescope at 12.5  @xmath0 m. the observations show that the central nucleus of all three galaxies contains a strong point - like nucleus surrounded by a lumpy ring. in one case, the structure of the central source   is resolved by deconvolution of the observed nucleus with a size of 0@xmath2.1.
the made - to - measure ( hereafter ` m2 m') method is a powerful technique for generating @xmath0-body initial conditions for galaxy models.   it works by first integrating many orbits over many orbital times in an assumed gravitational potential, whereby recording their properties in an orbit library, and then superposing them such that a best fit to the data is obtained. in this paper,   i revisit the m2m method and propose several modifications aimed at improving it, in particular the appropriate time scale for adapting the particle weights of the @x Math0- body model.
we derive an expression for the generalized differential phase contrast associated with aberrated linear shift  invariant optical imaging systems employing statistically stationary partially coherent scalar radiation, for which the output spatial distribution of spectral density ( i.e., the output image ) can be modelled using the transfer function formalism.   this extends previously reported work by paganin and gureyev  relating to a partially coherent treatment specifically for propagation  based phase contrast imaging based on the transport  of  intensity equation that has been reported . in this paper   we extend this work by extending the scope of the derivation to fully coherent complex scalar fields imaged using aberrated angular shift   invariant linear systems using partially coherent fields, under the imaging assumption that the object under study is a pure thin phase object. as a result  , we obtain an equation that describes the action of partial coherence in the modulation of the output transverse spatial distributions of spectral densities of partially coherent complex wave  fields.
silicene is a two - dimensional buckled material which is closely related to graphene.   it has been proposed as a potential candidate for overcoming the limitations of graphene because of stronger intrinsic spin orbit coupling ( 4 mev in silicene and @xmath1 mev ) in graphene @xcite. here  , we study the effect of strain on the electronic and mechanical properties of free standing silicenes using first - principles calculations. by applying strain up to 20%, we calculate the corresponding band structure and evaluate the dependence of the induced doping on the strength of the biaxial tensile strain. furthermore, we studied the phonon spectrum to address the stability of the system and calculate the grneisen parameter.
we simulate compact super - clusters of young massive star clusters in the tidal field of a host - galaxy and investigate the influence of orbital and internal parameters on the rate and timescale of the merging process.   the simulations are performed with the particle - mesh code superbox ( fellhauer et al., 2000 ). for each super - cluster we have two levels of high - resolution sub - grids which stay focused on the objects and travel with them through the simulation space, providing high resolution at the places of interest ( in this case the super - clustering and the single clusters within ). using the newly available parallel version of superbox, we find that the initial velocity - distribution of the super-clusters is very similar to that of the individual star clusters. however, the speed of the merger process is much faster than expected from the observed rate of the formation of new star clusters as well as the number of star clusters able to survive the merger. by simulating the properties of the resulting merger object we show that it is possible to predict the evolution of the interacting star clusters and their dynamical evolution over time.see research article http://www.biomedcentral.com/1471-7007/
abstractthe evolution of thermal plasmas in supernova remnants ( snrs ) is a dynamical time - sequence of shock - heated gas.   recently, suzaku has discovered strong radiative recombination continua ( rrcs ) in the x - ray spectra of three snrs, ic443, w49b, and g359.1@xmath60.5 ( @xmath2 ), which have a radio shell with centrally - filled thermal x - rays. here   we study the central bright region of w28 ( g6.4@x Math60.1 ) with the xis as a part of the recombining plasma survey project ( pi : koyama, k. koyamasu, s. takahama, h. j. yamaguchi, c. d. shimadzu, m. b. nakamura, e. l. chan, f. k. o. tsugamushi, p. kazumura, i. z. segami, j. t. u. rosat, and c. v. ramachandran, et al. 
massive mimo full - duplex relaying ( mm - fdr ) is a promising approach to achieve energy efficient transmission of multiple source - destination pairs with very large antenna arrays at each base station ( known as " massive mimo " system ).   this paper focuses on the transceiver design for Massive mimo systems with hardware impairments such as phase noise, nonlinear power amplifier, i / q imbalance, non linear low - noise amplifier and adc impairments, which must be considered in the design of practical massive mimO system.. the effect of hardware impairions is modeled using transmit / receive distortion noises @xcite. by applying the proposed model,   the effects of these impairments are simulated using real - time transmission data from the sources and destinations. it is shown that the performance of the proposed transceiver scheme is improved by reducing the distortion noise caused by the ei cancellation without instantaneous ei channel.
the dyson - schwinger equations ( dses ) are a nonperturbative means of studying qcd in the continuum.   the chiral limit is strictly defined by @xcite, where the renormalisation - point - invariant current - quark mass is determined by the ghrelin - lemeshow regularisation of the poincar invariant regularisation integral. in this limit   it is possible to unambiguously define the gauge invariant vacuum quark condensate in terms of @xmath20 @xcites.. the question of whether @x Math12 has an expansion in current -Quark mass around its chiral - limit value bears upon the radius of convergence for chiral perturbation theory. with this question   one is asking whether it is able to write @x math21 on a measurable domain of current -quark mass.    it was found that such an expansion exists for @x maths22. here   we present a new study of the long - range interaction between light - quarks in qcd using the dse results as a probe of the confinement of light- and antiquark quarks.
the production of quarkonium at the large hadron collider ( lhc ) at 7  tev and up to 2.3  pb@xmath3 is measured using the atlas detector.   the results are compared to predictions made by the colour evaporation model, fixed - order next - to - leading log ( fonll ) and colour singlet nnlo calculations for the @xmath0 production cross - section and the production fraction from the decay of a @x Math1-hadron to inclusively - produced @x maths0 ( hereafter referred to as the _ non - prompt fraction _ ) in the decay channel @xMath11 as a function of both @x math0 transverse momentum and rapidity in @x mathematics12 collisions at the lhC.    the results show that the inclusive @x mathematician0 productionCross - section is larger than the prompt @x mathematical0 production Cross - section which is produced directly from the proton - proton collisions or from decays of heavier charmonium states like the @ xmath15 or @Xmath16.  also, the qcd2 production fraction is smaller than the corresponding predictions made
a sequential fourth generation of fermions is one of the simplest extensions of the standard model.   interest in this fourth generation has waxed and waned over the years, and it is now clear that it is unlikely to be detected at the large hadron collider ( lhc ) due to the presence of a massless fourth generation neutrino. here   we study the production of sequential heavy charged leptons in @xmath13 using precision electroweak data from the international linear collider at the 99.999% cl with a nonzero mixing angle of @x Math14 gev. for the first time, we find that the mass splitting between the charged lepton and the neutrinos is not constrained by the mass spectrum of the first three generations, but rather by the constraints on the oblique parameters of the combined electroweak experiments.
the gamma - ray burst of 28 february 1997 ( grb 970228 ) was a watershed event in the study of gamma -ray bursts, especially at optical wavelengths.   the afterglow phenomenon, long - lived multiwavelength emission, was discovered following grb970228 in the x - rays and optical. despite intense efforts,   early spectroscopy of the apparent broadband break of the sn component failed to reveal the redshift of the gamma - Ray burst. through the preponderance of redshift determinations and the association of grbs with faint galaxies, it is now widely believed that the majority or all of long duration ( @xmath2 s ) gamma -Ray bursts originate from cosmological distances.. however, the nature of the progenitors of these bursts is still poorly understood. here   we show that the presence of a supernova component in the postglow of grb 980326, which was first observed by reichart and galama et al. in 1999, relies critically on the knowledge of the red shift to grb 960326 to set the restframe wavelength of the visible component. using the new data from the _ hubble space telescope
summaryngc  4552 ( @xmath20,@xmath21, j2000 ) is an elliptical galaxy located east of m87 in subcluster a of the virgo cluster.   we have measured the distance modulus of the galaxy s surface brightness fluctuations ( cold fronts ) using high - resolution x - ray spectroscopy and found that the temperature of the interstellar medium ( ism ) is strongly influenced by the ram pressure experienced by the galaxy as it moves through the dense icm gas. at the leading interface between the galaxy and the icm,   the galaxy experiences a sharp rise in surface brightness ( gas density ) accompanied by a corresponding drop in gas temperature, which is due to the stripping of gas and energy from the galaxy into the surrounding icm by tidal and hydrodynamical forces. here  , we show that the magnitude of this change in gas density is proportional to the number of stars in the galaxy, and that the size of the cold front is determined by the ratio of the intensity of the stripped gas to that of the ambient gas. for the first time, we find that the strength of the heat - induced by the stripping process can be used to estimate the
an observing campaign to determine the q0957 + 561 a, b gravitational lens time delay has been undertaken.   we present reductions of ccd images for the determination of the b image brightness record, and the determination by re - analysis of extensive older data sets of a refined value of the time delay from 417 days to 417.4 days. in this report we provide additional remarks about the data reductions and their relationship to the telescope and camera properties.
the kuiper belt is a population of low - inclination icy bodies that has been proposed to exist beyond the orbit of neptune.   the dynamical structure of this population has been the subject of several recent theoretical studies, and the results of these studies have been compared with those of the recent @xcite study on the origin of the observed short period comets from the solar system. in this article  , we analyze the orbital plane perturbations of the newly - discovered kuipeper belt objects, which were first discovered in 1992 at a distance of 41 au from the sun ( qb@xmath4 ), and discuss the possible existence of a larger population of similar objects in the region between 35 and 50 au.
the josephson effect has implications going beyond electrical transport @xcite. in 1965,   maki and griffin predicted that the interplay between cooper pairs and quasiparticles in tunneling events would provide heat currents with quantum coherence.   this phenomenon manifests itself as a phase - dependent component of the heat current flowing through a thermally - biased josephalic junction ( jj ), which should, therefore, enable the realization of heat interference.. a _ magnetic flux - controllable _ superconducting heat interferometer was recently theoretically conceived and subsequently experimentally realized experimentally @xxcite ; this achievement served to show, on the one hand, how quantum coherent extends also to dissipative observables such as heat current. on the other  , these devices might constitute the building blocks for the implementation of superconductor - based hybrid _ coherent caloritronic circuits consisting of, for instance, thermal modulators, heat transistors, splitters, etc. here   we review recent advances done within the emerging field of _ coherent Caloritronics.
the mori - zwanzig ( mz ) formalism of the reduction of partial differential equations ( pdes ) is one of the most commonly used reduction formalisms for systems of ordinary differential equations which are larger than any available numerical resolution.   the main difficulty in constructing an accurate reduced model is the need to estimate the rate at which activity is propagated from the resolved scales to the unresolved scales. here   we present a new method for estimating the rate of propagation of activity from the resolve to the unpolished scales of a reduced model of a singular pde using the mz formalism, which is based on the fact that the solution of the pde becomes underresolved when it develops activity at a scale smaller than the smallest scale available to the simulation. by taking into account the time course of the simulation, we show that the @xmath0-model can be used to predict the behavior of the remaining unresolved scales of the reduced model accurately and reproduces correctly the features of the original equation at the length scales that are available numerically.
in the framework of friedmann - robertson - walker ( frw ) models of cosmological expansion there are important constraints which have to be satisfied by primordial matter fluctuation fields and which are common to all models independently on the nature of dark matter.   the first issue concerns the statistical properties of initial matter density fields in standard cosmology models : in these models dark matter plays the dominant role of providing density fluctuation seeds which, from the one hand are compatible with observations of the cosmic microwave background radiation ( cmbr ) and from the other hand they are large enough to allow the formation, through a complex non linear dynamics, of galaxy structures we observe today. in this review   we discuss the main issues related to the use of primordial dense matter ( cdm ) as an initial matter field in the context of frw models of Cosmological structure formation and we focus here on three different issues, where the methods and concepts of statistical physics find a fruitful application @xcite. some very interesting analogies with glassy systems ( e.g., one component plasma ) will be outlined and the crucial observational tests of standard models ofCosmic structure formation will be discussed.
the relativistic heavy - ion collider ( rhic ) and the large hadron collider at cern are designed to produce an equilibrated phase of deconfined partonic matter : the quark gluon plasma ( qgp ).   the nonequilibrium stages in the evolution of the qgp are poorly understood and it is a contemporary challenge to develop a description of the spacetime evolution of an ultra - relativismic collision ( urhic ) : from particle production in the collision, through equilibration and plasma formation, and on to hadronisation. here   we employ a flux - tube model to describe the pre - equilibrium particle - production stage in the development of a qgp and use that to calculate the thermal dilepton spectrum and its evolution from impact to equilibrated.. the model is based on a quantum vlasov equation with a non - markovian source term and a relaxation time approximation for the energy - density flux tube that describes the excited domain of the plasma. using this approximation, we show that the temperature - dependent decay of the highly excited qcd vacuum occurs via a nonperturbative process analogous to the schwinger mechanism
quantum computer ( qc ) can be used to simulate the property of a superconductor, such as the bcs model. in this paper  , we show that qc can be applied to calculate the spectrum of the hamiltonian (  ) of a metal supercond conductor @xcite using nuclear magnetic resonance ( nmr ) qc.   based on a concrete scheme of quantum simulation on nmr qc which includes a method for choosing an appropriate working initial state and the usage of twice fourier transforms, we experimentally obtained the spectra of the bbs hamiltonia, which coincided with the theoretic expectations.
the decay phase of a c8 flare is made of two distinct phases : an impulsive phase, when magnetic energy is suddenly released and plasma is rapidly heated to temperatures that may exceed 15  mk, and a long decay phase, where the plasma cools back to lower temperatures.   x - ray spectroscopic observations of the decay phase have invarably shown a slow decrease of the plasma temperature, down to a few million degrees. in 2003, feldman   et al. ( 2003 ) reported on sumer observation of the evolution of the post - flare plasma from the Impulsive phase down to below 1  mk. here  , we investigate in detail the scenario of thermal non - equilibrium in the final phase of the flare decay, using a state - of - the - art time - dependent loop hydrodynamic code which includes non equilibrium ionization. by comparing the observed light curves of all lines emitted in the late phase of flare decay with those of a standard flaring loop simulation,   we show that thermal non-equilibrium develops naturally in the decay in agreement with observations, and that it is able to explain well the sequence and timing of appearance of the observed lines.
the appearance of active galactic nuclei ( agn ) depends strongly on orientation.   the current paradigm for agn includes a central engine, surrounded by an accretion disk and by fast - moving clouds, probably under the influence of the strong gravitational field, emitting doppler - broadened lines. in radio - loud objects   we have the additional presence of a relativistic jet, roughly perpendicular to the disk, which produces strong anisotropy and amplification of the continuum emission. this axisymmetric model of agn implies widely different observational properties ( and therefore classifications ) at different aspect angles. hence the need for " unified schemes " which look at intrinsic, isotropic properties, to unify fundamentally identical ( but apparently different ) classes of agns.    the main change in our understanding of unified schemes of bl lacs since the first bl lac conference in como was the discovery of large - scale samples of the extended radio emission from fanaroff - riley type i ( fr i ) radio galaxies, which are thought to be the most likely parent population of bllacs.
the new earth similarity index ( nesi ) is re - defined as geometrical mean of six physical parameters ( namely : radius, density, escape velocity, surface gravity, revolution and surface temperature ).   since revolution is not directly available as the raw data, here the values are calculated for 3370 ( as of september 2016 ) confirmed exoplanets. in this paper,   the nesi has been introduced and analysis of 3370 confirmedExoplanets are done, section 3 has the results of tsi, and section 4 gives the discussion and conclusion part of the work.
we present a semiclassical approximation to the quantum transmission problem of quantum scattering at a critical energy where classical transmission mechanisms turn on.   we use the wigner - weyl calculus to derive a transmission matrix which represents a probability of transmission as a function of phase space and we find that above threshold the support of this transmission matrix closely mimics the shape of the classically reacting region but the weyl symbol itself also incorporates tunnelling and other quantum effects. for explicit illustration we present results in phase space, using the waveguide problem from @xcite.
the ionosphere is a major obstacle for interferometric observations of astronomical sources.   this is especially true for images of objects with relatively small angular sizes, such as those observed by the very large array ( vla ) interferometer in new mexico and the westerbork synthesis radio telescope ( wsrt ) in the netherlands. to make an image of the ionosphere, one must remove phase terms from the ionospheric phase terms during the fourier inversion process involved in making an image ; this is usually done through a calibration process which estimates the required phase corrections. here  , we present a method for estimating the phase of the complex gain for each antenna based on the difference in the total electron content ( tec ) observed along the lines of sight from the two antennas to the observed object at different spatial frequencies using a combination of linear fit and partial least squares fitting methods. when the tec data are used as a reference for the calibration process, the resulting phase corrections can be used to determine the absolute phase of each antenna's complex gain.we find that the best way to estimate the phase corrections is to choose one antenna for the interferometry and to set the
the theory of gravitational lensing has reached a considerable degree of sophistication over the last decade.   theorems have been found predicting the number of images in very general systems, and various universal behaviors of images have been discovered for sources lying near caustics. while these general results have been complemented by a number of detailed calculations for specific types of lenses, the majority of such calculations have been performed within the quasi - newtonian viewpoint of gravitational telescope lensing commonly used in astrophysics. here  , we review the theoretical properties of plane wave spacetimes, a subclass of plane - fronted waves with parallel rays. using the penrose limit, we show that plane wave spacetimes are geometrically mild and admit a wide variety of interesting phenomena.    we find that the bending of light by plane - symmetric gravitational waves can be considered as a dynamical process involving the formation of multiple images.. the effects of these effects are discussed in detail, and some of the most interesting ones are discussed.
we study the coupled schrdinger equations with a kerr non - linearity where @xmath1 is a gain - loss parameter.   we find that the system with constant gain and loss can be reduced to a first - order differential equation with polynomial nonlinearity and possesses blow - up solutions. by deriving an averaged equation, the rapid modulation in time of the gained and loss profile   is shown to provide a controllable expansion of the region of exact parity - time ( pt ) symmetry, depending on the strength and frequency of the imposed modulation. using melnikov type analysis and topological degree arguments, we prove and derive conditions for the existence of periodic ( libration ), shift periodic ( rotation ), and chaotic solutions in the system.. we also derive an approximate threshold for pt - broken phase corresponding to the disappearance of bounded solutions.
hydrogen peroxide ( h@xmath0o@x Math0  ) is a well - studied system because of its unusual properties, particularly the almost freely rotating oh moieties.   the vibration - rotation spectra of hydrogen peroxide have attracted significant attention, both experimental and theoretical. for example it has been used as a benchmark system with large amplitude motion for testing different variational nuclear motion codes @xcite. in this paper   we present a variational approach to the assignment of vibrational states and line lists for h@ xm@x maths1 transitions involving high rotational states using the effective hamiltonian approach. by using approximate kinetic energy operators,   these calculations are able to reproduce the known vibrational band origins with an average accuracy of 1 @xmath2.. the results show that the analysis of the vibrational bands of h@Xm@h@x math1 transitions can be improved by using more accurate variational calculations.
we have carried out simultaneously the radio astronomy observations in the radiotelescope utr-2 by two different antennas in the same frequency band.   one of them was an array of 720 dipoles, and another consisted of one. to examine what intensity of solar bursts one would be able to detect in the first and the second case, we have compared the ordinary simultaneous observations, carried out by the array of720 dipoles ( a part of the radiolucentope utrs-2 ) and the waves wind instruments. for this purpose   we have used a two - channel discrete spectrum analyzer ( dsp ) that is used as a back - end to the antenna directional pattern of utr-. the data obtained from the two antennas were compared using the raman spectra of the wavewinds instrument. on the basis of the results of these comparisons,   it is shown that the effective area of the space telescope is about 1.5 times larger than that of the ground - based instrument, and the difference is not statistically significant.
gringo is a new version of the asp grounder gringo, which was originally developed by @xcite in 2009.   gringo is an extension of the recently released gringo grounder @xmath2, which includes several features that are not covered by the proposal from @xaite. among them are integer intervals, pooling, and binary relations between counting and constant constants.    gringo also includes a new set of rules for choice rules \{a }, which does not have the same semantics as those of the ones proposed by@xcite.
electron - electron correlation in strong laser fields has attracted a great deal of attention for over a decade, in particular in the context of laser - induced nonsequential double and multiple ionization @xcite.   the electron - electron interaction plays a huge role in the formation of these peaks, which are often attributed to the inelastic recollision of an electron with its parent ion. in the past few years, however, there has been increasing interest in below - threshold intensities, for which the kinetic energy of the recolliding electron is not sufficient to release a second electron by electron - impact ionization. in this case, the second electron is promoted to an excited bound state, from which it subsequently tunnels. using saddle - point methods, we model this physical mechanism within the strong - field approximation ( sfa ). employing a semiclassical action and slowly varying prefactors, we show that the corresponding transition amplitude for the resi mechanism is written in terms of a semisymmetric action and slow - varyingPrefactors. employing saddle -point methods,   it is possible to relate the solutions of the saddle - points to the classical trajectories of an electrons rescattering with its
we discuss an alternative class of quantum measurement, where a signal is unambiguously extracted when it is in a particular target state, i.e., unambiguous quantum state filtering.   we derive a rigorous formulation of the optimal measurement for our problem and generalize it to the case of more than two signals. as concrete examples, we consider the sensing of two practically important operations in quantum channels consisting of non - unitary operations as an example of applications. to sense small decoherence parameters of such channels, we need to detect the mixed state probes appropriately. here  , we discuss the detection strategy based on unambiguous state filtering and propose possible experimental implementations.
the mid - infrared ( mid - ir ) imaging and spectroscopic survey of nearby galaxies using the infrared array camera  ( irac, *?????   * ) and the multiband imaging photometer  ( mips, *????,using archival data from the _ spitzer _ space telescope, we have identified a large number of point sources in the galaxy @xcite that are visible in the irac @xmath11,@xmath12, @x Math12, #14, #15, #16, #17, #18, #19, #20, #21, #22, #23, #24, #25, #26, #27, #28, #29, #30, #31, #32, #33, #34, #38, #39, #40, #41, #42, #43, #44, #45, #46, #47, #48, #49, #50, #51, #52, #53, #54, #55, #56, #57, #58, #59, #60, #61, #62, #63
identifying members of known moving groups ( mgs ) or open clusters can provide an important constraint on their age and composition.   low - mass stars and brown dwarfs ( bds ) members of these groups can provide important feedback to atmospheric and evolutionary models of such objects at young ages, which currently await good calibration from constraints on age and compositions. in this paper   we present the last in a series of results of a major survey of ultra - cool dwarf objects in young moving groups. for the first time  , we have studied the atmospheres of a large sample of very low mass star and brown dwarf objects with a spectral classification of m7 or later corresponding to teff@xmath12500 k. we find that the atmosphere of the hyades supercluster ( hy ; 600 myr ), the ursa major group ( siriussupercluster ) ( si ; 300 myr), the ic 2391 superclusters ( ic ; 35 - 55 myr),the castor moving group ( ca ; 200 myr).we also find evidence for the presence of li  i 6708 in a sample of objects previously classified as members of a mg based on kinematic
conformal gravity ( cg ) is an alternative theory to standard model of general relativity.   it is able to solve some problems of einstein gravity, and it is worth investigating this theory in more detail. here  , we study geodesic equations for spherically symmetric in the vicinity of blackhole in conformal gravity with a spherical symmetry. using the analytic solutions of the differential equations of motion in schwarzschild ( anti ) de sitter spacetime, we find that the geodesics are solved in terms of elliptic weierstrass elliptic function in the case of null geodesical and derivatives of kleinian sigma functions in the cases of timelike geodesia. also, we discuss about the effect of the linear term in the metric on the perihelion shift in the time like geodesives. finally, we plot some possible orbits of test particles and light rays in the region of black hole in the form of fly by orbit type for null geode.
noncommutative gauge theories are highly nonlocal.   the main difficulty is that the nonlocality of these theories arises from the non - decoupling of uv and ir states, which leads to ambiguities in the distinction between short and long distance physics. here  , we review the basic ingredients of the dipole interpretation and the matrix formulation of noncommutation theory and discuss the general form of the gauge invariant perturbative corrections to the quantum effective action that result from integrating out uv states. based on this structure,   we show that the leading long distance interactions cancel at each order in perturbation theory for supersymmetric theories. moreover, we argue that, beyond one loop order, uv - ir mixing generally introduces divergences that spoil the consistency of the theory.
the fulde - ferrell - larkin - ovchinnikov ( fflo ) phase is a superconducting phase with oscillating order parameter ( op ) in real space.   the fflo phase can be expected in materials with relatively high maki parameter, when the orbital critical magnetic field ( maki ) is greater than the paramagnetic critical field ( pfm ). here   we analyze iron - based superconductors ( ibsc ) ( pnictides ) using the three band model proposed by m. daghofer _   et al. [ m.daghofer et al.:   j. chem. phys.2013, 34, 549 ].    the results show that the f flo phase is present in most of the ibsc systems studied and that the observed phase transition from convectional superconductivity to the f floating phase is due to pair hopping interaction between the two spin - dependent quasiparticles.
we present the first simultaneous observation of euv waves and a moreton wave by using euv and h@xmath0 images with high spatial and temporal resolutions.   we found not only a winking filament on the disk, but also an oscillating prominence on the limb, triggered by the coronal wave ( moretonwave ).. these findings are consistent with the theory that moreton waves are the intersection of the fast - mode magnetohydrodynamic shock propagating in the corona with chromosphere.
single- and few - layers of transition metal dichalcogenides show promising electronic, optical, and mechanical properties and are considered as potential candidates for future electronic applications @xcite.   single - layer mos@xmath0 has attracted the attention of scientists because of its high direct band gap and low low - field mobility. in the present work,   the effects of biaxial and uniaxially strained strain on the low - fields mobility of single - Layer mos@Xmath0 are investigated by using ab - initio simulations along with the linearized boltzmann transport equation ( bte ) and the density - functional theory ( dft ). under strain, the energy distance between the lowest and the second lowest minimum in the conduction band is evaluated to be 160 mev, which is very close to the experimentally measured value of 1.85 ev at the k-valley of @xmath2/q=1.9 ev @xcide.    scattering rates due to intrinsic phonons, charge impurities, and remote phonons are taken into account. 	 the results show that the effective masses and energy differences between valleys in the Conduction Band are reduced
accretion discs play a central role in a wide range of astronomical environments, mediating the gas flows in the vicinity of object as diverse as agn, binary stars and protostars. in an accretion disc,   the predominant flow is a circular shear flow, with angular velocity @xmath0 a function of radius from the central object.   accretion takes place because of the action of some form of dissipation which releases the free energy of the Shear flow as heat, and so allows the disc material to fall deeper into the potential well of the central objects.    simple physical energy arguments indicate that the dissipative process must take the form of a stress which transports angular momentum outwards. however, in a recent paper, hayashi & matsuda ( 2001 ) have drawn attention to the fact that attempts to provide a physical explanation of the above result in terms of simple kinetic theory have resulted in failure. in this paper  , we show that, although it is obviously necessary to include coriolis force if one works in a frame co - rotating with the flow, one can obtain the correct result from straightforward kinetic theory in the inertial frame.
in this paper, we apply the well - developed methods of statistical physics to economics and society in order to gain insights into probability distributions and inequality in these systems.   we consider three specific cases : the distributions of money, income, and global energy consumption. in all three cases,   the common theme is entropy maximization for partitioning of a limited resource among multiple agents. despite the difference in the nature of the considered variables, we find a common pattern of inequality in each of these cases. in the first case, we show that the probability distribution of money in a closed economic system is similar to the boltzmann - gibbs distribution of energy in physics ; in the second case, our results show that there is a local conservation law for money ; and in the third case, it is possible to derive a quantitative study of the probabilities of energy consumption per capita around the world using the same general mathematical problem as the one described in the previous case.
the galactic center ( gc ) region in the high energy band has strong emission lines at 6.4, 6.7 and 7.0 kev which are k@xmath2 lines from neutral, he - like and h - like fe ions, respectively ( e.g. @xcite ).   the most probable candidates responsible for these lines are magnetic cataclysmic variables ( mcvs ) and/or active stars. here  , we report the discovery of a new probable mcv at the close vicinity of the radio pulsar psr b1737@x Math030 with the spin - down luminosity of @xmath4 erg s@x math5 @xcites.    the integrated spectra of the x - ray spectra resemble the gcdx in the k@Xmath2 line features ( @xaite, @xmaite ), and hence the origin of the tev gamma - ray emission is still debatable.
we propose a method of trading off performance for accuracy using sampling in vertically split datasets.   we suggest a specific way to perform sampling in vertical split datasets and calculate sample size given acceptable error. the proposed method is tested on a calculation of intersection set cardinality, together with a proposed heuristic algorithm. as a proof of concept  , we demonstrate the performance improvements of the method on a case of non - cooperative data providers.
in the context of string theory, brane models are interesting from both phenomenological and cosmological viewpoints. in the previous discussions@xcite, in which the dynamical effect of " our brane " has been neglected, it was concluded that thecosmological production of monopoles and domain walls is negligible in the models of brane inflation.   later in ref.@xcites, however, it has been shown that the formation of these types of structures is quite natural in generic cosmology scenarios. in this review,   we discuss the essence of the previous arguments that were used to exclude the cosmologically produced monopoles or domain walls in the model of branes inflation.
carbon nanotori are carbon nanotubes in which the ends of the tube are identified and sewn together to form a torus.   they have attracted a great deal of experimental and theoretical attention since the discovery of @xcite, which shows that these nanot tubes can be parametrized by four integers @xmath0. here  , we demonstrate that there are additional symmetries that relate _ physically distinct   carbonnanotori to each other, forcing them to exhibit identical energy spectra and electrical properties. as we demonstrate, these so - called " modular " symmetry structures arise solely in the process of compactifying the graphene sheet in order to form the nanotorus. however, to the best of our knowledge, the significance and consequences of these asymmetries have not been fully appreciated thus far in the literature. for example, when we identify two carbon atoms on a graphene sheet whose positions differ by an arbitrary lattice vector, we can partition the set of carbon nantori into distinct equivalence classes as far as their spectral properties are concerned, and this leads to a dramatic reduction in the number of _ spectrally distinct _   ( but not  physically distinct
the microwave characterization and study of dyba@xmath8cu@x Math9o@x math2 ( dybco ) monodomains at microwaves in the mixed state is presented.   the main experimental quantity in microwave experiments is the effective surface impedance, which is measured by means of two cylindrical resonators, a silver - coated metal cavity @xcite and a dielectric resonator ~48.3 ghz and 47.7 ghz, operating in the te@xMath11 mode at approximately 48.3 Ghz and 49.5 ghz for the cavity and resonator, respectively. to investigate the effect of vortex motion on the electromagnetic field - dependent cavity quality factor and resonant frequency, we use the surface perturbation method, with the sample under measurement replacing one of the cavity bases. from the results obtained,   it is concluded that the polarization of the quasi - particle density of states in the vortex cores can be explained by the presence of vortices, which are set in motion by the lorentz force exerted by microwave currents.
the glauber dynamics of the random energy model ( rem ) like trap model proposed and studied in @xcite and inspired by the rem model is studied.   the average density of small eigenvalues of the rem like trap models are studied numerically for the glass phase, and the arrhenius  like regime is compared with the nonarrhenius regime for the smallest eigenvalue density. to understand ageing in the thermodynamic limit, the variations of the correlation function (  ) with the system size have to be carefully studied. as a result, the results show that the mean time of ageing depends on the variation of the diffusion rate and the number of microcanonical states, but also on the interplay between the overlaps between these states.
the spin-1/2 @xmath0 model is a well - known model for quantum spin chain compounds.   it describes a uniform nearest - neighbor exchange coupling with uniaxial anisotroy, and the observed intensity spectrum can be interpreted in terms of constituent quasiparticles. here   we present a new approach to the analysis of the @x math0 model that combines older and more recent results for the unified purpose of understanding the composition of the@x Math0 spectrum more thoroughly. using the bethe ansatz method, we show that the spectra of quantum spin chains are composed of many different kinds of quaiparticles, which are characterized by string particles of complex momenta with common real part and different imaginary parts. at the planar regime,   the strings are constituent particles of ( degenerate ) multiplets of eigenstates with total spin, which split up energetically at the top of the spectrum. on the other hand, at the axial regime, the fragments of the string particles form a set of states of low energy that join up in new degenerate configurations, reflecting different symmetries.
thick discs are ubiquitous in the local universe.   they are most easily detected in close to edge - on galaxies in which they appear as a roughly exponential excess of light a few thin disc scale heights above the midplane. here   we study the radial profile of thick discs in two different types of galaxies, co11b and ngc  4013, using a comprehensive detection and modeling of thick+thin discs started in co11 b. we find that the thick discs have a radical break in the radial light profile at high redshift, with a large fraction of the stars breaking off from the thick disc during or shortly after the formation of the galaxy. this break is caused by the collapse of some of the star - forming clumps of material from the primordial galaxy discs, which would have been formed from the dissolution of giant clusters of giant star - formers. for the first time, we show that the break phenomenon is also observed in low - mass galaxies, where the thick disk is dominated by a small fraction of lagging and/or counterrotating stars rather than the larger fraction of stars previously thought to be the main thick disc component.    the break is explained by the separation of the
we present 4 simulations for the same initial condition with nagataki ( 2009 ), but with different kerr parameters.   it is shown clearly that a more rapidly rotating black hole is driving a more energetic jet. especially, in the case of the schwartzschild case, no jet is found. by performing a simulation for that case  , we can clearly see how effectively the rotating blackhole is working to drive the jet.
compact groups of galaxies are associations of three to seven galaxies, where the projected distances between them is of the order of their diameters, and where the group shows a low velocity dispersion, making compact groups an ideal place to study galaxy interaction and intergalactic star formation.   the main goal of this work is to search for a link between the evolutionary stage of a group and the presence of young intergalaxy objects which may have formed during galaxy interactions. for this  , we analyze a subsample of seven compact groups ( hcg 2, 7, 22, 23, 92, 100 and ngc 92 ) which span a wide range of evolutionary stages, from hi rich groups to strongly interacting groups, where these groups show tidal tail features and a deficiency in neutral hi gas. in order to analyze the evolutionary stages of each group, we used new fabry - perot velocity maps, galex / uv data and optical r - band images. while ultraviolet light contains important information regarding the age of the young stellar population that may be present in the intergalastic medium, we searched for ultraviolet emitting regions in the vicinity of all seven targets, using the sextractor software ( se, ( *
the method of maximum relative entropy ( mre ) is a technique for assigning probabilities and updating them when new information is given in the form of constraints on the family of allowed posteriors.   the purpose of this article is to illustrate the use of the mre method as a tool for attaining approximations for ferromagnetic materials that lie outside the ability of traditional methods. in doing so, we further the previous work done and show the versatility of the method which has been shown to be useful in several other applications.
the light front approach of dirac@xcite is a relativistic methodology that is broadly applicable to nuclear physics.   the aim of this work is to develop a technique that could have wide application in nuclear physics by applying it to three different examples- lepton - nucleus deep inelastic scattering, high energy projectile nuclear scattering and high momentum transfer quasi - elastic reactions involving nuclear targets. here   we combine the previous formalisms to obtain a light front treatment of a chiral lagrangian which contains pions, vector and scalar mesons, and which respects the constraints of chiral symmetry. using the light front quantization procedure, the necessary contact interactions involving the exchange of instantaneous fermions and vector bosons   are obtained. for each case, the kinetic variables are quantized at the zero of light cone time @xmath18, and the energy momentum tensor, the light back hamiltonian and the plus momentum operator are derived. as a proof of the applicability of the present formalism, we study and check the present formallyism by comparing it with the results of experiments on three different systems of two hadrons.see research article http://www.biomedcentral.com
the leading log ( ll ) bfkl resummation of the mueller - navelet dijet production process at a hadron collider makes some approximations which, even though formally subleading, can be numerically important at present collider energies.   we report on studies of the effects of including energy and momentum conservation in the ll bf Klarke   fock leading log reconstruction of the gluon exchange in the @xmath5-channel with a two - parton invariant mass from the chain of emitted gluons from the bfkrl1/bjorken ( bfka ) coupling on the qcd prediction for the hadronic dijet cross section at lhc energies.
the coalescence of binary black holes is one of the most promising sources of gravitational waves for interferometric gravitational - wave detectors, such as ligo, virgo and geo600.   current searches for gravitational waves from binary black - hole coalescence use matched filtering to search for a waveform buried in noise. using the high - accuracy caltech   cornell numerical - relativity waveforms, we suggest improvements to the analytic post - newtonian waveforms that are currently used in the searches by ligo and virgo to improve the detection efficiency of the matched - filter signal - to - noise ratio ( snr ) generated by matching the data stream to the template waveform. here  , we describe the construction of a pn   nr hybrid waveform that can be used to estimate the snr of a match - filter search based on the waveform @xmath5 + 0.1    0.2   where the data source is a stationary gaussian noise process with a one - sided power spectral density given by@xmaths. over the course of this paper, we show that the hybrid wave form is more efficient than the existing templates for searching for gravitational
the phenomenon of shear localization during high strain - rate deformations of metals @xcite is a striking instance of material instability in mechanics, that has attracted considerable attention in the mechanics literature.   we develop a mathematical theory for the onset of localisation and the emergence of a nonlinear localized state, thus providing a rigorous justification to the behavior conjectured by the effective equation in@xcite.we employ the constitutive hypothesis of an _ exponential law _ for the viscosity coefficient, which admits a special class of solutions describing uniform shearing, and thus the deformation of uniform shear is characterized by strain softening response. using a linearized analysis of the base solution around which we linearize, we show that the system is asymptotically stable for the initial value problem, but unstable in the complementary region where the stress vs. average strain response is monotonically decreasing, and that the formation of coherent shear bands is followed by localisation of the shear at the interface between the two states. on the other hand, the effect of thermal diffusion can be assessed : perturbations do grow initially in the early stages of deformation, but over time the effects of the diffusion intensify
iterative linear matrix inequalities algorithms ( ilmis ) are often used to solve problems of optimization in systems and control theory, often non - smooth, non - convex and np - hard or of unknown complexity.   we present a new approach to the design of a reduced - order positive filter for linear systems, which is based on the estimation of an unmeasured output from the measured output of a system using the filtering error transfer function of the system's filtering error system. as a proof of concept  , we compare the performance of the proposed method with that of general purpose optimization solvers, which are intended to minimize any user - defined function.. the performance can be compared in three directions : 1 ) objective value, 2 ) computational time and 3 ) user time.
the source of the superconducting trasition in the high @xmath9 cuprates of ybacuo compounds is not clear.   it is widely believed that the interaction between the cuo@xmath4 planes and the chains is responsible for the formation of the induced gap in the chains, but a proximity model has been proposed to account for the condensate on the chains. in this article   we investigate the influence of coupling to the chains on the penetration depth of the chain layers in a simple proximity model which assumes that the pairing interaction is intrinsically @x Math8 wave in the @x math1, @x maths2 and @x mathematics3 directions.    we find that the temperature dependences of the thermal dependence of the penetration depths of the two models are very different from those of experiment.. the temperature dependence of both models is dependent on the strength of the coupling across the quaternary junction between the chains and the planes.
barred magellanic spirals are a common intermediate phase in the hubble sequence between late - type spiral galaxies and irregular galaxies.   they are characterized by a single, strong, spiral arm ; a bright, off - center bar ; and often a high degree of asymmetry in morphology and/or kinematics. here   we present high resolution neutral hydrogen data for the interacting magellic spiral pair ngc 4618/4625. from our data we show that these galaxies are remarkably symmetric, despite their close proximity in the viewing plane. to explore the nature of the interaction, we analyze the galaxy's h  i profiles, velocity fields and rotation curves using the very large array ( vla ) in the c configuration. while the dynamics of the galaxies are not significantly different, the rotation curves of the interacting galaxies are more symmetric than those of the non - interacting galaxies. additionally, we calculate interaction timescales and degrees of morphological asymmetry with respect to the observed interactions.
we analyze the relations between galaxy structure and photometric parameters vs. cluster s environment.   our sample consists of 507 galaxies in 14 southern abell clusters with @xmath10 corresponding to the southern abelli clusters redshifts survey ( sars, paper i ). from the listed clusters we have finally analyzed a total of 1384 galaxies ( cs1 sample ), of which 345 have known redshifting ( cs2 sample ). using the standard b + d law, we find that the radial velocities of the bulge and the disk are significantly affected by the environment of the cluster. when the cluster is considered as a whole, the radial velocity dispersions of the two components are positively correlated ( r = 0.972, p < 0.001 ). on the other hand,   the luminosity profiles of the three major components are negatively associated with the clustercentric distance normalized to@xmath9 ( r > 0.874, p<0.001).our results suggest that the environment affects the properties of galaxies in clusters in many ways.
in this paper, we introduce a simple network growth process with addition and deletion of nodes.   we show that it is possible to obtain closed equations for several structural properties of the network such as the in - component size distribution, the fraction of dangling nodes, the degree distribution, and the diameter of the most connected node using approximate theory and numerical simulations.
we show that the uncertainty of the photocount statistics of a radiation field depends on the number of modes, including the energy distribution among the modes, and on the spectral properties and quantum correlations of the radiation field.   we also show that it is not possible to provide a " better " illumination at the point where the mode structure is known at the source but the frequency spectrum is perturbed in some uncontrolled way before it reaches the location of the detector ( dynamic speckle ). this effect is most prominent on small length scales and is particularly prominent in the intermediate regime of modern optical lithography.
the stueckelberg mechanism is a generalization of the higgs mechanism that allows one to introduce a mass for a @xmath1 vector boson in a way that retains gauge invariance.   it is shown that this can be used in conjunction with other models involving gauge symmetries, such as supersymmetric gauge models and spin - two models.
the glauber model ( gm ) is a well established model for describing heavy ion reactions at high energies.   it is a semiclassical model picturing the nuclei moving in a straight path along the collision direction, and gives the nucleus - nucleus interaction @xcite in terms of interaction between the constituent nucleons ( nn cross section ) and nuclear density distributions. here   we reexamine the various trajectory corrections in the gm and calculate the total reaction cross section as a function of energy upto 50 times the coulomb barrier. to quantify the energy range in which a particular correction is effective  , we quantify the center of mass energy of the system and find that the above modifications to gm are insignificant.
the behavior of the electronic wave - function phase in an actual quantum transport device has been studied with the help of lattice models.   these models allow to describe a dot of arbitrary shape and to study the influence of disorder. in this paper   we introduce a generic lattice model for a quantum dot coupled to single - modulated leads and show that the transmission phase can depart from the friedel phase at the points where the modulus of the transmission vanishes. as a function of the gate voltage,   the scattering phase exhibits an abrupt jump of @xmath0 in the valleys between the peaks of the coulomb blockade regime. on the other hand, for weak disorder one can identify certain dot levels which are much more strongly coupled to the leads than average. in such cases, the dot levels are populated in an anomalous way as a result of the presence of zeroes in the transmission through the quantum dot.
we present an analysis of the optical depth distribution of a projected galaxy pair ugc  5041, using near - ir observations.   we find that the extinction of the background galaxy from the foreground disk is @xmath20 in the b - band near the spiral arms, and@xmath21 in the interarm - regions.. the observed optical depth distibution ( p@x Math3 ) is used to explore the under - representation of quasiexperimental absorption spectra ( qsos ) lensed by spiral galaxies and of qso with low redshift damped absorption in the x- and y-bands.    the results are compared with those of previous studies on the same galaxy pair, which have been performed using different selection biases and with different types of background sources.
the successful running of the long - range high - energy cosmic microwave experiment ( lhc ) during 2010 - 2012 has resulted in large data samples on sm standard candle processes such as heavy gauge boson production and decay to lepton pairs for atlas and cms.   such data signal the arrival of the era of precision qcd, with predictions for qcd processes at the total precision tag of @xmath2 or better for the total theoretical precision of (  ) or better. here   we present comparisons of the attendant application of exact amplitude - based resummation theory to recent data from the lHc using a paradigm opened by (  ) for precision Qcd via comparisons with recent data.
the seventh - year wilkinson microwave anisotropy probe ( wmap ) data rigorously test the standard cosmological model placing constraints on its basic parameters.   the wmap measurements alone are not enough to break the degeneracy among some cosmologic parameters or to place constraints on non - standardcosmological models. in this paper  , we perform a joint analysis of the cosmic microwave background ( cmb ) - wmap7 data, constraints on hubble expansion rate inferred from the age of astrophysical objects using lookback time method ( lbt ) and measurements of the gas mass fraction of relaxed clusters from chandra x - ray observatory(chandra ). by combining the three data sets, we find that for a flat universe @xmath10 at @x Math8 cl is the best constraint on the dark energy density parameter @x maths1 and for a time independent equation of state @x math2, the best constraints on the Hubble expansion rate are @x mathematics3 at@xmath4 cl and @x laws of thermodynamics at@Xmath5 cl, respectively. for a galaxy cluster with a relaxed gas mass fractions of ~30% of its total mass,
in - medium hadronization can serve as a way to study the jet space - time development if the medium properties are well known, like in semi - inclusive deep inelastic scattering @xcite, or as a probe for the medium property, like jet quenching effect observed in heavy ion collisions @xmath12. here   we combine the hydrodynamic mechanism from@xcite with the pqcd calculations attempting at a description of data on the production of high-@xmath0 hadrons in hypertonic ( lhc ) and low - ionic ( rhic ) collisions at different centralities at @xMath13 and @x Math5.   the results show that the observed behavior towards smaller jets, steeply rising and shaping a bump, is quite different from the one observed at larger jets, due to the contribution of the hydrophilic mechanism responsible for the evaporation of hadrons from the created hot medium.
we perform a set of 75 simulations of clouds exposed to ionizing radiation.   the aim of this work is to answer questions of whether the incident ionizing flux is able to trigger the formation of new stars or not, and how the process and the properties of this star formation are connected with the intensity of the incident flux. in the first part of the simulations   we use the smoothed particle hydrodynamics ( sph ) code seren, fully described in ( *????   hubber et al.  ), with an ionization routine based on the healpix sphere tesselation code.    we run simulations with a wide range of emission rates @xmath16, where @x Math17. 	 we show that as the mass of the bonnor - ebert spheres decreases, the cloud appears to survive longer in the ionized state, and the rate of star formation increases.. however, when the initial mass of each cloud decreases, it becomes gravitationally unstable and the outer parts collapse to form new stars. during the maximum compression phase, the inner parts of the cloud become more stable and the surface of the core becomes more compact.
the generation of twin photons inside a nonlinear crystal by the phenomenon of spontaneous parametric downconversion ( spdc ) has been extremely useful for studying fundamental aspects of quantum mechanics and to physically implement quantum information protocols in recent decades.   this usefulness is due to the photon pair being entangled in many degrees of freedom, including energy, momentum, angular momentum, and polarization. in this paper   we derive an expression for the quantum state of the twin photons generated in the process of spdc using a simplified version of the example presented in our recent work,@xcite in which the interaction between light and matter is treated using the bialinicki - birula  sipe photon wave function formalism.we show that the twin - photon wave functions can be obtained by coherently summing all possible probability amplitudes for the generation of two photons from the same incident pump photon at different positions @xmath0 without any interaction with the scatterer. on the basis of these approximations, we derive a general expression for calculating the twin-photon wave function.
we present first results of our data compilation and studies concerning the 22 tentatively identified egret objects ( tids ) which may exhibit significant emission beyond 10 gev and for which the next - generation cherenkov telescopes may provide the clue to their final identification.   these objects justify a closer examination since for their tentative counterparts various pieces of information exist which are not available for the other unids : we have an exact source position which can be targeted, and we know the source type and have therefore at least vague model predictions for the spectrum beyond the egret energy range. in this article   we examine:   what is the predicted emission of the tid?   which of the four observatories can observe the object? * is the emission variable?,what is the angular size of the tentative counterpart?,are bright stars nearby which may influence the sensitivity of the cts?,the chances are there for a detection if the tentative identification turns out to be wrong? will new pointings be necessary?
we have carried out neutron diffraction experiments on solid hexagonal close packed ( hcp ) solid @xmath0he crystals to look for traces of a supersolid transition in the bulk material.   the results show that the mean square displacement of the nuclei of the crystalline sample is significantly higher than the lindemann criterion, and this is attributed to the formation of a crystalline lattice of@xmath5he in the crystal lattice.
the fate of non - rotating massive stars, as an extreme of failed supernovae, in the mass range of @xmath24050m@xmath1, is one of the key issues in stellar physics as well as astrophysics.   the black hole formation is triggered by the intense accretion of matter onto the proto - neutron star and the neutrino burst is unique to the death of such massive stars. here  , we discuss the evolution of the blackhole formation associated with the short burst of energetic neutrinos from the gravitational collapse of the 40m@Xmath1 star and its potential use as a probe into the equation of state of dense matter.
large space - time volumes with the highest energy density to date, over 15 gev/@xmath1 in typical estimates@xcite, have been produced in 200  gev au+au collisions at the relativistic heavy ion collider ( rhic ) @xcite.   strongly interacting matter is predicted to be in a phase commonly referred to as quark - gluon plasma ( qgp ) at such high energy densities, and the presence of this phase manifests itself in the equation of state, which ( together with the initial conditions ) determines various measured properties and serves as an input to fluid - dynamical calculations. it has been argued recently that the systems produced in these collisions behave as a perfect fluid with negligible viscosity, and this conclusion was based in part on the agreement of the flow quantity @xmath3 with the prediction of an ideal - fluid calculation. here  , we address these issues with the help of data on the relevant performance of the star detector @xaite. for the first time, we present results without and with smearing of the detector s zero - degree calorimeters ( zdcs ).. the results show that the flux quantities @x
inflationary theory of the early universe is a well established paradigm able to solve most of the hot big bang puzzles and to explain the generation of the almost scale invariant spectrum of coherent primordial perturbations giving rise to structure formation @xcite.   the main purpose of this short letter is to extend this analysis to the scalar sector and to make explicit the equivalence between the stationary point picture and the @xmath2-attractor formulation of inflation, which is currently the most widely used model of inflation. in this paper   we construct a general scalar inflationary theory containing a stationary point of order@xmath1 at some field value. using an effective field theory approach, we show that the existence of a higher order stationary point in the potential of a scalar field can give rise to local inflation in the flat area surrounding it. as long as all derivatives of the potential with respect to the inflaton field are well - defined, this property translates into a set of conditions on the equations of motion for any integer @x Math17 in terms of the coefficients of the inflationary potential. by taking into account the presence of a single stationary point,   these conditions are equivalent to the
the yuan - tseh lee array for microwave background anisotropy ( amiba ) is a platform - mounted 7-element interferometer operating at 3-mm wavelength to study the structure of the cosmic microwave background ( cmb ) radiation.   it is being constructed as part of the cosmology and particle astrophysics ( cospa ) project, funded by the taiwan ministry of education initiative on academic excellence. in this paper  , we describe the design and construction of amiba, the first observational results, and the proposed use of the thermal sunyaev zeldovich effect ( sze ) for measuring the angular power spectrum of the cmb radiation.
the problem of error correction in network coding has received significant attention due to the fact that pollution attacks can be catastrophic.   the injection of even a single erroneous packet somewhere in the network has the potential to corrupt each and every packet received by a given sink node. here   we investigate the effect of the min - cut from the adversary to a sink node on the rate of reliable communication in a network using a series of simple changes to the induced network topology. for each of these changes, we show that the number of packets transmitted per generation is not significantly affected by the network capacity ( per transmission - generation ) but by the distance from the source to the sink node ( i.e. the amount of time it takes to transmit a corrupt packet ). when the network is controlled by a single node, the influence of an adversary is small, but if the network are controlled by more than one node, then the influence becomes very large.
the topological insulator is a new state of matter which is characterized by an insulating bulk and surface edge modes@xcite.   it is robust against perturbations such as disorders and impurities as far as the gap does not close. in this paper   we address the problem if a superstructure is a quantum spin hall ( qsh ) insulator as well and if there exists a similar topological phase transition. to demonstrate these novel phenomena, we carry out a numerical analysis by taking an instance of the ( @xmath0 ) superstructure on the structure of the ag substrate@xfite. using the effective low - energy dirac theory  , we show that two degenerate dirac cones are merged into two undegenerate hexagonally warped cones in the presence of infinitesimal coulomb interactions.    we present a general criterion when the topological phases may occur in superstructures. in the instance of silicene-1,2-diphenyl-3,4-tetramethylamino-6-sulfonic acid ( dpph )   superstructure, it is shown to be topologically connected to silic
we show that the skyrme parameterization of the self - consistent mean - field theory of binding energies, also called density - functional theory, can be used to reduce the effort required for a search for new theories of nuclear binding energies based on quantum many - body theory.   we use the chebyshev norm as a norm for the fit, which allows one to screen theories and their improvements taking only the information on a small set of nuclei, the  worst cases " of the baseline theory. by calling attention to these cases  , it could be helpful to experimentalists choosing which nuclei to study, and to theorists searching for missing ingredients in the baseline theoretical.
we investigate the cr @xmath2 near - edge structure ( xanes ) and extended x - ray absorption fine structure ( exafs ) signals of the crc@xmath11 carbide phase in amorphous nanocomposite chromium carbide thin films by experiment and _ ab initio  calculations, including metal cr for comparison.   we use the so - called _ stochastic quenching _ ( sq ) method to model the formation of non - crystalline phases in the presence of neutral atoms and substrate temperatures below the melting point of the carbide during physical vapor deposition ( pvd ) of the metal carbide. as a function of carbon concentration,   the sq results show that the c   @x Math = 1:1 ratio of cr@x maths2 + 1:3 is the most stable in the range of 0.5 - 2.0 at.% of carbon, with the exception of the high amount of @x math10-hybridized graphene - like carbon in the amorphously formed carbon - rich phase, which is more or less constant in carbon content. using the same method, we find that the values of the s
abstractthe type ia sn  1998bu is the slowest known supernova ( sn ) with a decay rate slower than the expected rate.   it was discovered on may 9.9 ut by @xcite in a spiral arm of ngc  3368 ( m96 ), a nearby sab galaxy, and was spectroscopically normal before and around maximum. during monitoring of the nebular phase of sn  ia, we found that the luminosity decline was not declining with the average rate predicted by cepheid - based distance measurements. this, combined with the change in the spectral appearance of the emission tail, gave the first evidence of the emergence of a light echo in sn 1998bu @xcitite. here   we present the observations along with a simple modeling of the evolution of the light curve of sn “ 1998bu” using the eso  3.6 m telescope and the efosc2 telescope at the time of its discovery.
wolf - rayet ( wr ) stars are the chemically evolved descendants of the most massive o type stars.   they have been suggested as possible precursors of core - collapse supernovae of types ib and ic @xcite. in this work   i report the discovery of two new wn6h and wc type wr stars in the direction of circinus, which were detected by the 2mass k@xmath3-band eso - ntt - sofi h- and k - band spectroscopy. from the use of the galactic rotation curve,   their far and near heliocentric distances of 11.6 kpc and 3.9 kpc, respectively, are computed.  a strong - lined spectrum reminiscent of young hydrogen rich _ main - sequence _ wN6h stars such as hd93162 ( wr25 ) in car ob1 and hd97950 in ngc3603, which due to their high - luminosities drive dense and fast winds, appear mimicking the spectral appearance of wr stars, seems to be the case for wr67a and wr67b.
we present a new three - dimensional ( 3d ) self - consistent - field technique that is capable of building the full range of incompressible riemann s - type ellipsoids with nontrivial internal flows ( i.e., not just the uniformly rotating jacobi configurations, which are thought to be the end point of secularly unstable stars driven by viscosity, and stationary dedekind configurations ) as well as compressible triaxial models that share the same divergence - free velocity field as riemans.   our compressible models satisfy the steady - state euler s equation exactly, but only satisfy the equilibrium - state continuity equation approximately, hence they are only in quasi - equilibrium. here   we show that these models can be used effectively as initial configurations for a hydrodynamical study of the stability of nonaxisymmetric configurations of compressible analogues of rieman s -type ellip so - called " quasiexperimental " models.
the equation of state ( eos ) of isospin asymmetric nuclear matter at supra - normal densities is of prime importance for the investigation of nuclear structure, heavy - ion reaction dynamics, and many issues in astrophysics.   recently, massive neutron stars ( ns s ) with @xmath2 have been identified with the high - precision measurements. considering the phase transitions in the ns core and the eos constraint from the collective flow data at high densities, it is difficult for the nuclear models to reproduce ns s as massive as @x math2. in this work, we consider the effect of the u - boson on the softened eos due to the hadron - quark phase transition in the psr j1614 - 2230 pulsar neutron star ( ns ) cores. using the relativistic mean - field ( rmf ) theory, we adopt the mit bag model for quark matter and the hadronic model for hadronic matter to describe the mixed phase of hadronic and quink matter. by considering the softness of the models, we show that the u-boson stiffens the hybrid eos initiated with different hadronic models. since quarks in the bag model are
we present a new method for the study of self - gravitating systems, for which the stationary out of equilibrium state ( ss ) state often has a peculiar core - halo structure.   the system consists of azimuthally symmetric particles with the total mass of @xmath0 in a two dimensional space. at the initial particle distribution, the system relaxes to a quasi - stationary state ( qss ), in which it stays for time, after which it crosses over to the normal thermodynamic equilibrium with the maxwell - boltzmann velocity distribution. by taking into account the existence of three distinct classes of particles, we find that the relaxation process proceeds in two steps : first, the particles are distributed over the phase space with the initial distribution, and then allowed to relax. when the relaxation is complete, the population of particles which will form the central core forms a halo, and the population which will evaporate forms a central core. using the one particle distribution function, we show that the life time of the qss diverges from the equilibrium state in the infinite particle limit, where the equilibrium is never reached, and that the ss state can be described by the usual equilibrium statistical mechanics.
the strong field approximation ( sfa ) is a theoretical framework that takes into account the long range of the coulomb potential in the interaction of atomic hydrogen with a strong laser field in a regime where tunneling is the dominant ionisation process.   this model has been introduced by tetchou _ @xcite and is based on the time - dependent schrdinger equation ( tdse ) in momentum space, which uses the velocity gauge and replaces the kernel of the nonlocal coulomomb potential by a sum of @xmath1 and @x Math2.    the results obtained from the sfa are compared with the experimental results using the riemann - schwinger model.. the results show that the sFA approach is able to reproduce the experimental data in terms of the kinetic energy of the laser pulse and the strength of the electric field at the laser turnoff without any significant changes in the quantum properties of the hydrogen atom.
the evolution of the magnetic field is akin to that of vorticity, a fact that has been noticed by at least one ( to our knowledge ) paper in the literature.   we have previously proposed a source - term alternative to the term of the biermann battery, which leads to magnetic fields that are usually quite weak initially ( @xmath11 g ) but thought to be subsequently amplified to the observed mean galactic values (@xmath12 g ) by dynamo processes. in this paper, we show that the poynting - robertson source term, which is proportional to the usual accreting source compactness, does not affect the evolution of cosmic magnetic fields within the volume of the disk alone. for plasma conductivity below a certain critical value ( and a free inner boundary condition that allows the accumulation of magnetic flux interior to that point ), we found a different regime in which the electromagnetic field accumulated around the gravitating object grows at a constant rate. as such, in several astrophysically interesting systems, magnetic fields may reach even equipartition values within astrophysicsically relevant time scales.
the cold fronts in the massive galaxy cluster abell2204 ( abell2142 @xcite ) show no sign of kelvin - helmholtz instability ( khi ) in the direction of merging, which has been proposed to be due to the suppression of khi by magnetic fields along the surface of the cold fronts.   we present an x - ray study of the two cold fronts found in the core of a2204, focusing on the two cfs in the cluster core. using deep observations and numerical simulations, we show that the temperature inside the discontinuity is lower than in the outside, whereas gas density drops abruptly, maintaining a nearly continuous gas pressure across the cold front. these characteristics are markedly different from those of shock fronts, which are thought to be the product of gas " sloshing" following a non - head - on encounter between two clusters. as a result  , we propose that the hot, dense gas in the central cold front is driven outward, where it is held by the cooler, less dense gas, forming a contact discontinuity.. the hot gas in this discontinuity also acts as a barrier to the flow of the cool, denser gas into the
in quantum cosmology, it is well known that the equations of state of matter fields are modified by quantum effects at small length scales.   this has mainly been studied so far for a scalar field for which quantum modifications can be so strong that negative pressure results independently of the chosen potential. here  , we study the effects of loop quantum corrections on the hamiltonians of the isotropic energy density and pressure equation of state in the form of an inverse power of the scale factor of the scalar with respect to the planck length. using the method of @xcite,   we show that the effect of quantum effects on these equations can be extended to the theory of the universe evolution from the big bang to the quantum transition through the big Bang singularity as well as from the expansion to the black hole phase.
the compact galactic bubbles ( ` mbs') discovered with the spitzer space telescope at @xmath1 by the mipsgal survey @xcite are characterised by an apparent roundish morphology, small angular dimensions and a usual lack of counterpart at other wavelengths.   they are thought to be the circumstellar shells of different kinds of evolved stars. in this paper   we report new observations searching for oh masers towards a sub - sample of 169 mbs. as an independent test to search for possible protoplanetary nebula ( ppn ) among the mbs, in section  we investigate the possible oh maser emission in these mbs.we find that about 80 percent of the samples have oh maser emission during the whole post - agb phase, or even later, which is associated with asymmetric stellar winds and circumstellar envelope ( cse ) formation. however, for spherical symmetric post - Agb stars ohmasers should be observed only in their early moments ( ~0.5 years ). since the present study is based on the analysis of the infrared morphology of known examples of ppne, we infer which would be the most likely expected morphology for a pp
abell 2029 ( a2029 hereafter ) is a rich cluster of galaxies at a redshift of @xmath8 @xcite.   it has been well studied optically, and can be characterized as a compact, relaxed, cd - galaxy dominated system, with no emission - line emitting galaxies within 600 @xmath1  kpc of its core @xaite. in this letter   we describe the global temperature structure, resolved metal abundances, as well as highly spatially - resolved spectral properties of the central regions.
we present a nonequilibrium strong - coupling approach to inhomogeneous systems of ultracold atoms in optical lattices.   the model is a fermi hubbard model for an optical lattice in a trap, where the on - site single - particle energy levels are determined by the trap potential and the global chemical potential. using a second - order self - consistent expression for the self - energy @xcite around the atomic limit which is described by @xmath12, we employ a time - dependent hamiltonian to drive the system out of thermal equilibrium. from the results of the simulation,   we propose a massively parallel algorithm which is used to solve the resulting equations on a supercomputer.
we present an improved semi - analytical method for the calculation of the self - energies of the nonequilibrium green s function ( negf ) for the electronic transport properties of quasi - onedimensional systems.   the new algorithm is based on the notion of a complex group velocity, which is recast into a more general form and applied to the construction of the surface green s functions ( sgf ) of the semi - infinite left- and right - hand side leads of an infinite quasi-1d system. in the second part of this work we present three examples of calculations performed with our new implementation, comparing the results to the ones obtained by using the original method of reference. however, although the algorithm appears very robust, our detailed error analysis reveals that for a given system the accuracy is lost at some specific energies.the physical origin of this behavior lies in the presence of surface states very weakly coupled to the quantum leads.
object registration is an important task in computer vision that determines the position and orientation of an object in camera - centered coordinates.   recent developments on visual depth sensors and their increasing ubiquity have allowed researchers to make use of the information acquired from these devices to facilitate challenging registration scenarios. unlike the aforementioned learning - based methods, the ones presented by novatnack _   @xcite utilize the detailed information of the scale variation in order to register range images in a coarse - to - fine fashion. here  , we present an architecture that exploits the scale - variant histogram of control points ( hocp ) features to construct a part - based implicit object representation for the registration of range images. using this framework, we extract the coarsest parts of the object of interest and then iteratively refine its alignment based on finer ( smaller ) parts that are represented with more discriminative control point descriptors. during inference,   the parts centered on the pixels that belong to the background and foreground clutters are removed iteratively using the most confident hypotheses and the test image is updated. since this removal process decreases the standard deviation of the test point cloud, subsequent normalization applied to the updated test image increases the
a two - dimensional model of traffic flow on a square lattice is introduced by biham, middleton and levine ( bml ) @xcite.   it is self - organized because whatever the initial condition is, one finds in the _ asymptotic _ configurations that, _ all _ the arrows move freely in their turns hence the velocity averaged over all the arrows is @xmath6, or they are _ all  stopped, with@xmath7. here   we give exact results on the lower critical density, below which there are only moving configurations asympticically, and an uppercritical density, above which there can be only jamming configurationsasymptotically. between these two critical densities,   the configuration can be moving or jamming, or even with both moving and blocked arrows, depending on the initial configurations. as indicated in the simulation, there is another critical density above which the asymptonotic configurations are typically ( but not always ) jamming. this is the sharp jamming transition discovered in the ensemble average velocity.
ngc 458 is a young cluster of intermediate - mass stars in the vicinity of smc.   it is one of the richest clusters in smc, but there is no direct measurement of its metallicity or reddening and the estimated age ranges from 50 to 130. here   we present a new cmd for this cluster based on the observations of 1056 stars by the eso ntt telescope equipped with susi ( la silla, chile ) and the 0.9 ctio telescope ( cerro tololo, chiles ).    the cluster core shows a well defined ms extending over about four magnitude in, = 18.2   is the estimated visual magnitude of the to, and a consistent population of evolved stars ( 34 stars ) can be recognized from @xmath1 to @x Math2. at the external region of the cluster,   a clump of field stars appears at@xmath4 and @x maths5 which has been already recognized to be populated by helium - burning intermediate mass stars belonging to the field. using the cm diagram of ngc 458 as a reference, we compare it with that of the lmc cluster ngc 1866 which
we study the effect of dark energy on the cosmological limits from cosmic microwave background ( cmb ) measurements on the shear ( and the rotation, etc. ), especially in spatially homogeneous ( sh ) cosmologies.   we use dynamical systems methods to revisit the constraints on the hubble - normalized shear scalar from cmb anisotropy measurements using expansion - normalized variables in bianchi type vii@xmath15 sh cosmologies. for a universe that is very nearly flat now and that was very Nearly flat at the time of last scattering,   the curvature of the universe can become significantly negatively curved at intermediate periods. at earlier times the matter dominates and the curvality is dynamically negligible, while at later times it can dominate. for such a universe, we find that the integrated effect from a small shear is not important.
the relationship between debris disks and planets is a complex one.   it has been predicted that neptune should create two dusty clumps just exterior to its orbits, one ahead and one behind the planet slightly outside its orbit @xcite. in this paper  , we use the venetia burney student dust counter ( sdc ), aboard the new horizons spacecraft, to investigate whether the clump will be detected by the sdc during its trip to the outer solar system. using a collisionless model of the edgeworth - kuiper belt ( ekb ) debris disk, we show that the observed clump does not exist, but that the expected data can be used to constrain the models. besides, we find that the impact rates of grains between @xmath5 in mass from the trailing clump are significantly higher than those from the main clump, which is due to the presence of collisions between the two parent bodies. moreover, the impact rate of the dust clump is much higher than that of the main cluster, and the effects of these collisions are more pronounced in the leading clump than in the trailing one. as a result, our results suggest that the existence of
in the real - time quantum chemistry framework@xcite, chemical systems can be interactively explored with a proper hardware device such as a force - feedback ( haptic ) device ( or an ordinary computer mouse ).   results of the calculations such as the total electronic energy and the forces acting on the atoms are immediately transmitted back to the operator. in this work, we develop efficient density matrix propagation schemes that can reduce the number of self - consistent - field ( scf ) iteration steps by extrapolation of converged density matrices obtained for preceding molecular structures of a real -time exploration. using these schemes, we show that the execution time of a single - point scf calculation can be reduced by up to 50%. when applying the proposed schemes to a set of model reactions, the calculated quantum chemical properties are comparable to those of standard quantum chemical methods.
we study the phase diagram of a two - leg quantum spin ladder system @xmath4@xmath0 chains using the bosonization approach.   we consider the model which we study in this paper consists of two coupled hamiltonian, @x Math4+@x math0 chains. for each chain,   the anisotropy of the leg coupling and the rung coupling are @xMath10 and @x maths11, respectively.    we find that the xy phase appears in the ferromagnetic region of the chain under the open boundary condition ( obc ) @xcite, and the gapless phase is extended to the antiferromagnetic Rung coupling region under the same boundary condition. by using the density matrix renormalization group ( dmrg )  , we show that the edge state does not exist in this model under the obc, since the ground state is in the haldane phase under the ab initio boundary condition ; however, it does exist in the zenkoff - legeza phase at the multicritical point near the Ferromagnetic phase.
nuclear magnetic resonance ( nmr ) has been known as one of the most viable methods for demonstrating even relatively complicated quantum algorithms.   however, the status of nmr has not been completely approved compared to the other candidates such as photons and ion traps, in that it treats an ensemble system composed of a large number of molecules. moreover, the states are mixed rather than quantum pure states. therefore, nearly all previous attempts to demonstrate nmr quantum information processing ( qip ) and quantum computations ( qc ) relied on pseudo - initialization@xcite of highly mixed states. in this work,   we show that with nmr mixed states, even if these states are definitely separable, still there is a considerably high probability to detect signals with appropriate signs which apparently imply transfer of two - bit message even though we encode only one qubit. here  , we introduce a new class of entanglement witness, which is based on measurement of nuclear spin magnetizations in a single run experiment. by means of this approach, we demonstrate that the probability of detection of signals with proper signs is higher than that of the conventional approach, in the sense that nuclear spin polarization should be increased above a certain threshold, and this
the creation of catalogs from astronomical imaging is a common practice in astronomy.   the process of catalog construction is so " baked in " to our ideas about what astronomy is, we sometimes forget that the catalog is not the fundamental data product of astronomy ; catalogs are produced from imaging ; their production involves many decisions and ideas that go beyond the information provided to the telescope by the incident intensity field. while the hard decisions of catalog making destroy information, it may be less lossy to pass forward not a catalog but a probabilisitic description of all the catalogs that could be consistent with the imaging  a posterior probability distribution in the ( enormously large ) space of possible catalogs. this article represents an attempt at implementing this ambitous goal in the specific situation where the only objects in the field are stars or other point sources.
the supercritical instability of a single coulomb center in gapped graphene has been studied by using the continuum model and the density functional theory.   the supercritical regime is reached when the charge of the charged impurities in the quasiparticles is subcritical, whereas their total charge exceeds a critical value for the appearance of quasibound states at the atomic collapse site. to understand the mechanism of this supercritical behavior, it is important to take into account the influence of magnetic field on the formation of negative - energy bound states in the quantum collapse in graphene.
a typical scientific research project requires a variety of computational tasks to be performed.   all too often scientists resort to a grab - bag of tools to perform these varied computational tasks. in this paper  , we outline a recent comparative genomics case study where python and associated community libraries were used to facilitate input of standardized biological data, create scientific plots, and provide solutions to speed up bottle - necks in the generation of data for experiments that are complicated by large amounts of data, or complex experimental procedures. using @xcite, we show how python can be used to generate simulation data, control instrumentation to capture data, and visualize data within the same computational framework as other commonly used tools such as matlab, mathematica, stata, spss or r.graphical abstract
the role of magnetic fields in cluster formation is a matter of debate.   recent numerical simulations of cluster formation suggest that a moderately - strong magnetic field is needed to impede star formation in molecular clouds in order for the simulated star formation rates to match observed values @xcite. here  , we present the results of near - infrared polarization measurements of the serpens south cluster in the spitzer gould belt legacy survey using the imaging polarimeter sirpol ( polarimetry mode of the sirius camera : *??? * ) mounted on the irsf 1.4 m telescope at the south africa astronomical observatory. by using two different wave - plate angles, we obtained 10 dithered exposures, each 10 or 15 s long, at four wave - plates ( 0@xmath10, 22@x Math10.5, 45@x maths10, and 67@x math10. 5 ) as one set of observations and repeated this nine or six times, respectively.    we find that the magnetic field in the cluster forming clump is strongly distorted by the supersonic turbulent flows around serpensor south. from these observations,   we propose that the region of serp
the heisenberg spin glasses ( sgs ) of the edwards - anderson model in three dimensions ( 3d ) exhibit a finite - temperature chiral - glass transition.   this observation is in contrast to the earlier numerical studies of the isotropic heisenburg sg in two dimensions ( 2d ), which suggested that the sg did not exhibit an equilibrium sg transition at any finite temperature. here  , we study the problem of the lower critical dimension ( lcd ) of @xmath6 in the limit of infinite dimensions, particularly for dimensions higher than@xmath7. using the heisenfeld sherrington - kirkpatrick ( sk ) model, we find that the lcd of the 3d heisenberger sg of  @xcite is approximately 1.5  0.2  kcal / mol, which is about the same as that of the corresponding mean - field model in the general space dimensionality @x math6. by comparing the results of the present work with those of the previous numerical works, we obtain the following conclusions : ( i ) the order parameter of the intermediate sg phase in the @x Math6 limit is the state of the he
hydrodynamic interactions in colloidal suspensions of birefringent spherical particles are well known.   however, their physical consequences have rarely been treated in literature. in the present paper, we study the rotational degree of freedom of two trapped spheres of equal size and show how it couples to translational and rotational dynamics. due to the axial symmetry,   the longitudinal motions parallel to the particle - particle axis decouple completely from transversal motions. by taking into account the rotation degrees of freedom, we obtain a rich spectrum of collective modes and correlation functions for the thermally fluctuating positions and orientations of the trapped particles and point out their interesting features.
@xcite recently reported spectroscopic observations of gcirs  16sw ( hereafter irs16sw ) that showed radial velocity variations consistent with a binary composed of two massive stars.   we have re - analyzed the data presented by @xcite as well as additional data from the same observing campaign, and find that the original data reduction process was seriously flawed. in particular, the color variation, light - curve asymmetry, and sign of the brightness variations that @xaite  presented are artifacts of the data reduction processes. to address these issues, we have developed a new model for the shape of the light curve that is consistent with an eclipsing binary system based on the best - fit model to the observed variations.graphical abstract
single trapped ion provides the cleanest quantum system available in nature.   it also provides a test bed for measurement of various fundamental properties of quantum mechanics and quantum field theories, such as parity non - conservation and measurements on limits of electron electric dipole moment@xcite as well as time variation of fundamental constants of nature @xcite. in this work  , we put forward a proposal for the measurement of berry phases and berry phase generated energy shifts using single trapped ion. to the best of our knowledge,   the only experimental observation of similar splitting and shift has been by r. tycko who used a single crystal of tetrabutylammonium sulfate ( tbcs ). in the present work, we show that we can generate berryphase and its associated energy shifts with modified ion trap geometry.    we also present a convenient technique for calculation of b Kerry phases in situations involving electric quadrupole moment interacting with a time dependent electric field gradient.
magnetoimpedance ( mi ) measurements of co - rich amorphous microwires with various ratios of the metal - to - glass diameter, in the  frequency range, carried out with a novel @xcite broadband technique.   the effects of the thickness of the glass sheath are clearly illustrated and the variation of the anisotropy field is evaluated directly as a function of stress.
ngc4388 is an almost edge - on sa(s)b galaxy in the virgo cluster.   it is a @xmath6-deficient galaxy that has undergone a stripping event by ram pressure, evident from the rapid decline of star formation. here   we show that the outflow of ionized gas from this galaxy is photo - ionized by the interstellar medium ( ism ) radiation from the agn and its polarization filaments are strongly polarized at the top with degrees of polarization of@xmath12. due to the inclination of the galaxy,   the emission from the northern outflow travels through the disk on the way to the observer, contrary to the emission of the southern counterpart, suggesting an internal asymmetry in the ism density close to the agN core.
we report a comprehensive study of analog hawking radiation effects in quantum fluid of light, specifically exploiting the quantum fluid properties of an exciton - polaritons condensate in semiconductor microcavities.   our theoretical model fully includes their intrinsically non - equilibrium nature and describes quantum fluctuations of the polariton field within the so - called truncated - wigner formalism of degenerate quantum gases. as a result,   we are able to provide quantitative predictions for the observable quantities, and to point out clear and accessible signatures of analog Hawking radiation in the emitted light from the cavity.
the wisconsin h@xmath0 mapper ( wham ) is a high - throughput optical spectrometer that has been used to detect and study faint, diffuse interstellar emission lines at optical wavelengths.   the presence of warm ionized gas ( h  ii ) in the interstellar medium can have a significant effect upon the interstellar pressure near the galactic midplane and upon the dynamics of hot ( coronal ) gas far above the midplane. here   we present some recent results from the wham northern sky survey as well as observations of much fainter " diagnostic " emission lines that probe the ionization and excitation state of the gas.
we present a detailed theory of magnetosubband and edge state structure in quantum wires with a hard wall confinement taking into account electron - electron interaction including exchange and interaction effects.   we employ an efficient numerical tool based on the green s function technique for self - consistent solution of the schrdinger equation in the framework of the density functional theory ( dft ) in the local spin density approximation ( lsda )@xcite. using the dft+lsda  , we show that the electrostatic screening in strongly modifies the structure of the edge states giving rise to interchanging compressible and incompressible strips.graphical abstract
wormhole solutions are necessarily associated with violations of the energy conditions, namely the existence of exotic matter.   the presence of a cosmological constant is also an issue that has been extensively analyzed in the literature. here  , we analyze the stability of a @xmath2-dimensional wormhole solution, using the darmois - israel formalism, within the context of the randall - sundrum brane world scenario, where our universe is viewed as a domain wall in five dimensional anti - de sitter space. considering a linearized radial perturbation around a static solution, in the spirit of @xcite,   regions of stability are discovered, which lie in a somewhat unexpected patch.see research article http://www.biomedcentral.com/1471-7007/1741-7006/8/5/3/1
the quantum hall ( qh ) system provides a rare " physical " set - up whose underlying mathematics is given by noncommutative ( nc ) geometry. in this paper, by taking a planar limit of the fuzzy supersphere, we construct qh liquids on a nc superplane, and investigate physical properties in a nac world.   it is shown that the ncsuperplane is realized by introducing the super gauge fields, and that the system possesses ( complex ) @xmath0 supersymmetry, one of which is dynamical and the other is non - dynamical. based on these results, we explicitly construct radially symmetric orbit states, which form a " complete " basis in the lowest landau level ( lll ), and show a super - chiral property where not only the orbital rotation but also the spin polarization is chiral. in section , a laughlin wavefunction and its superpartner on the ncsurface are derived. in sections  and , bosonic and fermionic topological excitations are presented, and their basic properties are investigated. finally, we discuss a possible
we present numerical simulations of the integrated soft x - ray and extreme ultraviolet emission determined from observations of 26 solar active regions.   we use photospheric magnetograms taken with the mdi on _ soho _ as the basis for extrapolations of the magnetic field into the corona. for each active region  , we use the inferred field line geometry to determine solutions to the hydrostatic loop equations based on volumetric heating functions of the form @xmath0 with both@xmath4 and @x math5 in the range 02. using the computed density and temperature structure for each field line to determine the expected response in eit and sxt, we find that the simulated emission is dominated by the transition region or " moss " emission, while the observed images show a combination of moss and coronal loops ( e.g., @xcite ). when we compare synthetic active region images with the observations   it is found that the simulation images are generally too bright. if we consider loops with expanding cross sections instead of constant cross sections, the calculated moss intensities can be brought into closer agreement with the observed data, but this, however, only widens the discrepancies between the simulated and observed total
the @xmath18 signal from the techni - pion + w channel for the intermediate mass standard model ( sm ) is a fake higgs boson.   we show that the rate, kinematics, and dependence on model parameters of the @x Math18 signal are similar to those of the observed excess in the cdf@xmath1 signal, and that the same range of parameters required to fit this excess can also be used to generate a @x math18 signal that fakes a higgs.. the results are particularly interesting given that both cms and atlas see a discrepancy between their observed and expected limits in the @Xmath18 channel for @x maths27  @xcite.
globular clusters ( gcs ) are an important fossil record of the evolution of physical conditions in galaxies, because the formation of massive clusters is triggered by shocks and high pressures in the interstellar medium.   there has been increasing evidence that young massive star clusters ( ymcs ) form in interacting and merging galaxies, and these are often proposed to be gc progenitors. however, whether or not ymc formed during mergers contribute to the present - day gc populations is still an open question. here  , we present a simulation of a wet galaxy merger, which to our knowledge is the highest resolution model of this kind so far. using a particle - mesh code to compute the gravitational dynamics of gas, stars, and dark matter, we show that the density and pressure required to form dense structures resembling super star clusters with typical masses of @xmath4  m@xmath2 can be resolved in a simulated volume larger than 100  kpc. comparing their gravitational and kinetic energy, we argue that they are tightly bound and likely progenitor of long - lived gcs.
we investigate the cosmological implications of the presence of a super - massive black hole ( bh ) in the centre of all galaxies with spheroidal components on the cosmic microwave background ( cmb ) anisotropies and spectral distortions.   we study the effects of the outflows, driven by the bh activity, on the gas within the seeded proto - galaxy. using the @xcite model, we show that the shock - heated gas will compton scatter the cmb photons and induce spectral distortions through the so - called sunyaev - zeldovich effect. to estimate the contribution of this effect to the global sz distortion of the universe, we generalise the description of the shock to the whole population of proto - galaxies and simulate maps of the induced secondary anisotropy. for each structure, we compute the predicted number density of primordial galaxies, using the predicted mass function of the #xcite mass function. from these predictions, we derive constraints on the model and compare our predicted global compton parameter to the one obtained by the cobe - firas instrument ( far infrared absolute spectro - photometer on board cobe ( cosmic background explorer ) at the time of galaxy
answer - set programming ( asp ) is an established approach for declarative problem solving and non - monotonic reasoning.   one of the central features of asp is grouping rules that are related in meaning into coherent blocks. here  , we propose a dedicated annotation language for asp that provides various ways to express meta - information for rules and other language elements. besides names, description, and arities of predicates, one can also specify the domains of term arguments of a predicate using respective language features for declaring types. this information can be used to support and ease the development process, test and verify programs, and to eliminate many sources for common programmer errors. while unit testing is an integral element in software development using common languages like java or c, it has been addressed in asp only quite recently  @xcite. we provide means to formulate unit tests for single blocks using, allowing for easy regression testing. after rules are grouped into blocks, we may use further annotations to declare respective input and output signatures, which are also useful for testing and verification. furthermore, we can declare the names and arity ofpredicates that are used within a block.    our annotation language can be exploited
we present the characteristics and performances of a demonstrative experiment devoted to the observation of ultra high- energy cosmic rays extensive air showers using a radiodetection technique.   the codalema ( cosmic ray detection array with logarithmic electromagnetic antennas ) experiment was set up at the nanay radio observatory in 2003. since mid 2004, it has been completed with four double plastic scintillators @xcite placed at the corner of the decametric array ( dam ) @xmath3. during the first period of observation, the setup was self - triggered using one devoted antenna : its signal was filtered in an appropriate noise - free frequency band ( 33 - 65  mhz ) chosen after an exhaustive study in the observed local noise frequency spectrum, before entering the adc. except for the trigger antenna, transient signals on the antennas were hidden by radio transmitters signals. consequently, a numerical passband filter ( same as trigger frequency band ) was applied, offline, in order to observe coincidences involving several antennas@xcite. using the position and the timing differences between antennas, it was also possible to perform the trajectory reconstruction of the electromagnetic plane wave using a triangulation techniques across the array @
tetrahedral symmetry of the fermionic mean - field is predicted for a number of nuclei.   the predictions are based on a very general analysis of symmetries of the nuclear mean - fields and are inspired by the group - theory considerations. in this paper  , we focus on the nuclei whose hypothetical tetrahedral - symmetry states can be found in the dedicated experiments ; we present examples of related means - field calculations and briefly discuss the envisaged experimental challenges.
the spontaneous symmetry breaking in double - well potentials is a fundamental effect caused by the interplay of nonlinearity with linear potentials featuring basic symmetries, such as double - wells.   the _ symmetry - breaking bifurcation _ ( sbb )  was originally discovered in a discrete model of self - trapping chris, and has been studied for gap solitons in dual - core fiber bragg gratings with the same kerr ( cubic ) nonlinearities as in the ordinary fibers @xcite. here  , we study the sbb in one - dimensional discrete lattices with the nonlineary tightly concentrated at two symmetric sites, or in narrow regions around them. to this end, we present a straightforward discrete counterpart of the double -Well nonlinear pseudopotential, which is characterized by the self - attractive self - attracting self - attraction of the interacting atoms into the double-well potential. using the schrdinger equation for a bose - einstein condensate as a model, we find that the sbbs are of the subcritical type, with the asymmetric branches emerging as stable ones and immediately going in the forward direction. on the other hand, the
fu orionis is the prototype of a small, but quite remarkable class of low - mass young stellar objects ( ysos ) normally referred to as fu ori objects ( fuors ).   for the first members of this class an outburst in optical light of up to 4 - 6 magnitudes over short time scales, followed by a decrease in luminosity over several years or decades, was observed @xcite. based on near - infrared and/or mid - infrared interferometry as a technique to study the inner few au of the accretion disks new insights to some of the best studied fuors were provided recently. in this paper   we present the first mir interferometric measurements of fu orioni. using the 8 - 13@xmath0 m spectrum of fu ori we show that the observed low k - band visibilities can be fitted with two models : one consisting simply of an optically thick and geometrically thin accretion disk and the other one consisting of an accretion Disk and an embedded " hot spot ".. the data are thus complementary to the nir observations of malbet et al. from their error statistics   it becomes clear that up to now no coherent
single - band point source catalogues of the far - infrared background ( firb ) have been generated from scan - map observations at 250, 350 and 500@xmath0 m made using the photometer array of the spire instrument on the esa   _ herschel_ space observatory.   the data were taken as part of the _ her schel _ multi - tiered extragalactic survey ( hermes ; oliver et al., in preparation ), using data from the science demonstration phase ( sdp ) of the survey. for each observation,   two separate observations were taken, offset from one another, in order to produce a more uniform coverage. for the lockman - swire field, two independent observations were also taken, separated by 38 days, to give complementary scan directions. with the help of these observations, we have developed a method for the generation of single - band points of origin catalogues for the firb, which are based on the identification of discrete sources of emission at 250,350 and 500°0 m.database url : http://www.ncbi.nlm.nih.gov/pubmed/edinburgh/entomology/
experimental data of photoproduction of vector mesons ( @xmath6 ) at resonance region @xcite are now being rapidly accumulated.   the extraction of the resonant amplitudes from the experimental data is expected to be useful to resolve the so - called " missing resonances " problem @xcites. in this work   we investigate the question about how these earlier models should be improved for a more reliable extraction of@xmath7 parameters from the forthcoming data. by using a coupled - channel formulation, we show that the extracted resonance parameters can be used to test the existing hadron models.
the star - formation rate ( sfr ) of galaxies is one of the most important diagnostics in understanding the evolution of galaxies.   it can be measured by measuring the ultra - violet continuum ( uv ) intensity of a galaxy and the nebular emission lines from the same galaxy at different redshifts. however, the main disadvantage of using uv / optical luminosities as tracers of the sfr is their sensitivity to dust attenuation. here  , we study the relative attenuation of the stellar continuum and nebular regions in high - redshift galaxies for which the calzetti curve is assumed to be applied to the continuum and the galactic extinction curve is applied to its nebular counterpart. with the use of the @xcite relation as a reference, we find that the spectrum of the hii regions of the local galaxy population is more attenuated than the interstellar region of the Milky Way at redshift @xmath7, when the universe was just 3gyr old, and this difference is due to the presence of higher dust absorption cross - sectional attenuation between the ionized gas and the surrounding stars. on the other hand, the spectra of the central mass of the neb
the discovery of a new class of faint dwarf satellites around the milky way ( mw ) and the andromeda galaxies ( m31 ) has opened a new window for the study of the formation history of large spirals.   the ultra - faint dwarfs ( ufds ) have been named because they have much lower surface brightnesses ( @xmath11  mag ), are very metal poor, and contain rr lyrae stars with pulsation periods suggesting an oosterhoff type ii classification. in terms of stellar metallicity and pulsation properties of the variable stars,   these systems could resemble the building blocks of the galactic galaxy at earlier times.
the problem of particle motion in electromagnetic fields is fundamental and pervades both laboratory and astrophysical plasma physics.   often, in order either to simplify the analytical work or to reduce the demand on computer resources, the system of interest is considered in only one or two spatial dimensions, with the hope that no essential physics will be lost. however, this approximation does have a number of important general consequences which can result in the loss of essential physics, and it must therefore be used with extreme caution. in the present paper   we present a rigorous derivation of the theorem regarding spatial constraints to charged - particle motions in an electromagnetic field which has at least one ignorable spatial coordinate, and discuss the application of this theorem to hybrid simulations of collisionless shock waves.
we propose the use of epsilon - near - zero ( enz ) materials adhered to the terraced exit surface of plano - concave transparent substrates to efficiently shape a plane wave into an aberration - free nonparaxial focused wave.   we design surface - relief structures using both metals and doped semiconductors as enz materials spanning the mid - ir, visible and uv spectral bands. in this way  , we can control the phase radiation pattern of a given impinging phase front and transform it into a desired shape by properly sculping the exit surface at the center of the enz slab.    our procedure is also adequate to generate non paraxial accelerating beams with bessel signature in miniaturized spaces @xcite.
the source 1e  1743.12843 was discovered during the first soft x  ray imaging observations of the galactic center region obtained with the einstein observatory.   its column density ( @xmath2@xmath3 ) is one of the highest observed in the X  ray sources of this region of sky, suggesting a distance similar or even greater than the galactic centre. to power the observed luminosity @x Math4 10@x math5 erg s@xMath6 accretion onto a compact object,   the source must be at least as far away as the galaxy center.    we have recently obtained a 70.4 ks long pointing centered on 1e - 1743-12843 in the context of our survey of the Galactic Center region with the @xmatrix0 satellite. for each observation and detector, we searched for periodic modulations in the x  rays flux of the source using the     method. from the results of these searches, we found that the source is a persistent
abstractwe report the observation of the 1998 outburst of the bromodeoxyglutamatergic hydrogen comet ( bh ), which occurred on mjd  51063 ( 1998 sep 7 ) at 843mhz.   we show that the hard x - ray emission from the bh is due to impulsive accretion of matter with low specific angular momentum, over the first few days, followed by a giant flare in both hard and soft x - rays about twelve days after the initial rise of the hard X - rays.
gravitational microlensing is a powerful technique for the investigation of the distribution of compact ( dark ) matter in the universe.   it also provides a powerful tool to study unresolved sources, such as in the case of the structure of quasar - like objects ( qsos ), through temporal differential magnification. here   we investigate the effect of a cosmological distribution of Compact objects on the surface brightness distributions of galaxies observed through galaxy clusters, focusing upon abell  370 as a case study. using a receiving field of 2 einstein radii, where @xmath14 is the mass of the microlens, we find that the surface bright points in the lensed part of the source galaxy show rapid fluctuations in surface brightness, with the largest fluctuations occurring in the star formation region, which is highly dominated by young, massive stars. from an observer s point of view,   these fluctuations are characteristic of a non - uniform source, composed of a number of bright points located in a more extended background ; hence, they should show quite a different variability imprint from the uniform sources typically considered in gravitational microlense experiments.. the nature of this imprint is the basis of this current contribution.
the dynamical casimir effect ( dce ), arising from movable external constraints, probes even more deeply into the complexity of the vacuum structure.   the dynamics of the geometry gives rise to a time - dependent casimir force along with a dissipative component. in the present study   we deal with the dce for a massless scalar field confined between two concentric spherical moving shells, and present a general expression for any law of radial motion of the shells  to compute the average number of particle creation. assuming, then, an oscillatory radial motion for the spherical shells, our results are applied to four different cases : when only ( a ) the inner or ( b ) the outer shell oscillates, apart from those where both shells oscillate ( c ) in phase or ( d ) out of phase. by considering the time evolution of the density operator of the cavity field and also by computing the well - known bogoliubov coefficients, we derive an effective hamiltonian for the problem and calculate the average numbers of particle production for each of the four breathing modes.
abstractthe formation of disk galaxies is a well - accepted model of galaxy formation.   the theory predicts that baryons cool and dissipate their gravitational potential energy to form a nearly self - gravitating disk of size, which cools and becomes gravitationally unstable to form massive clouds that fragment into stars that form a disk with an exponential surface brightness profile, a scale - length of a few kiloparsecs, and a central surface density of order hundreds of solar masses per square parsec for milky - way type spirals. in this review  , i will discuss the problems that have arisen with some of the proposed solutions to the problem of the self - regulation of star formation rate in disk galaxies.
the chandrasekhar fermi ( cf ) method is often used to infer the strength of the plane - of - the - sky component of the magnetic field in molecular clouds.   this can only be accomplished if and when the spatial orientation of theagnetic field is known, i.e., not only the orientation of its projection on the plane of the sky, but also its inclination to the line of sight. in this paper  , we discuss how a simple extension of the cf method can be used without the need for zeeman data to estimate the magnitude of the mean magnetic field for a given molecular cloud. by using spectroscopic measurements from suitable neutral and ionic molecular species, as well as polarimetry,   we show that our generalization is valid regardless of the field s orientation in space.
the latest issue of the journal of astrophysics and cosmology includes a number of papers on the study of molecular cloud turbulence in the milky way.   the main focus of this volume is on recent work analyzing and interpreting density and column density statistics, properties and definitions of clumps, linewidth - size relations, and statistics of polarization maps. as examples of the process of developing diagnostics of molecular clouds internal structure, kinematics, and magnetization from turbulent magnetic - field hyperdynamic ( mhd ) simulations,   my discussion here will focus on recently developed methods for characterizing these parameters from new simulations with a range of parameter values, and then use these results to select and calibrate diagnostics for the " reverse " process of discriminating systemic parameters from observables.
graphene is an electronic material with high electron mobilities even at room temperature.   chemical modification of graphene has been achieved by a number of methods and has been investigated by raman measurements and transport studies. until now, it is not so clear how conventional methods used in almost any graphene sample preparation, such as baking in inert gas atmosphere in combination with rinsing in water or organic solvents affect the electronic quality of a graphene system. in the first part of this work   we present a confocal raman spectroscopy analysis of graphene chemically modified with aromatic diazonium ions. a difference in reactivity between single layer,   bi - layer and single layer edge is observed.in the second part of the paper we first show the influence of functionalization on the electronic transport properties of graphene, and afterwards we focus on the effect of repeated treatment with baking and rinsed in isopropanol. here   our results show that the treatment with only isopropylammonium leads to an increase in the doping concentration and an asymmetry between electron and hole transport which is partly similar to the effects of the functionalization.    in addition we observe that the combined treatment with is
the bess-2001 balloon flight was carried out at ft.   sumner, new mexico, usa on 24th september 2001. during the flight,   the cosmic - ray fluxes and their dependence on atmospheric depth were measured by the bess spectrometer during slow descending from 4.5  g/@xmath0 to 28  g / cm2 for 12.4 hours. in this experiment, we used a first - level time - of - flight ( tof ) trigger to build a sample of unbiased triggers, which is a simple coincidence of signals in the upper and lower tof counters. using the cherenkov counter to record particles above threshold energy without bias or sampling, the fluxes of protons, helium nuclei, and muons were determined.    the results were compared with the predictions based on the hadronic interaction models currently used in the atmospheric neutrino flux calculations.
the virial equation of state ( eos ) is a mathematical representation of experimental results on the equations of state of gases and liquids.   it provides an expansion that gives the deviation from ideal gas behaviour in ascending powers of the density, namely the virial coefficients. for a simple fluid,   the virially coefficients are in general functions of @xmath6 alone, while in the case of mixtures they also depend on composition. here   we introduce a simple recipe to derive the compressibility factor of a multicomponent mixture of hard discs, hard spheres and hard hyperspheres in terms of that of the corresponding single component system@xcite using monte carlo integration. along the way we introduce slight modifications to our original proposal and consider an alternative eos to cope with mixtures very disparate in size.
we study the marginally stable modes of the s - wave and p - wave holographic insulator / superconductor phase transitions in ads soliton background at zero temperature using the quasinormal modes ( qnms ) of the scalar ( vector ) perturbations. by increasing the chemical potential from zero to some critical value  , the marginallystable modes will turn out.   this means at the critical chemical potential the ads solitation background becomes unstable and will prefer to be an ads solitons background coupled with nonzero charged scalar fields. on the other hand,   the quantum mechanical properties of the system are not affected by the changes in the chemicalpotential.
anti - de sitter ( ads ) and quantum chromodynamics ( qcd ) has been applied successfully in various fields. in this manuscript, we use the ads / qcd holographic wave function to calculate the @xmath1 production in photonproduction process.   the amplitude of the vector meson production in the diffractive process contains three parts, they are the light - cone wave function of the photon, the cross section of the dipole scattering off the proton and the wave functions of the vectors meson. in order to compute the differential cross sections of the@xmath3 in thediffractive process, we firstly integrate the values of @x Math3 and @x math4. then, we compare our prediction with the experimental data of the hera. according to the results of the correlation analysis,   we can reproduce the difference between the predicted and experimental data.
the spreading of wave packets in disordered nonlinear lattices has regained a lot of interest recently.   many experiments were performed with ultracold atomic condensates in random optical potentials   @xcite. due to disorder, linear waves which correspond to noninteracting condensate   will eventually stop spreading and exponentially localize in low dimensions. here   we study the influence of synthetic gauge fields on the spreading of nonlinear waves in a discrete nonlinear schrdinger model on a two - leg ladder lattice. for charged particles,   the magnetic field breaks time - reversal symmetry ( trs ) and therefore enhances the localization length in a disordered system. for neutral particles, like bosons, we introduce artificial gauge fields  . it turns out that each of the effects mentioned above exhibits its dominant role in different parameter and time regimes.
a new method for calculating the motion of a point particle coupled to a gravitational field on a fixed background is presented.   the method is based on averaging the effects of the particle s own fields on the background geodesic orbit in a time - averaged fashion, and then using local energy conservation to calculate the effect of the perturbations caused by these forces on the body s orbit from the local stress - energy conservation of the background spacetime. as a proof of principle,   we show that this method can be applied to the case of a small object in a circular orbit on a schwarzschild background which is coupled to an electromagnetic field in minkowski spacetime and a linearized gravitational field in a vacuum background ( e.g., a solar mass star falling into a supermassive black hole ) with good agreement with the literature.
the existence of a strange quark matter ( sqm ) phase in the interior of neutron stars has been suggested as a possible stable or metastable phase of nuclear matter.   it is usually described in the framework of a bag model i.e.  as a non - interacting fermi gas of quarks at zero temperature, taking into account the bag constant @xcite. however, recently medium effects were included in the equation of state ( eos ) of sqm in the frameworks of the mit bag model. here   we study the influence of these medium effects on the gross structure of non - rotating hybrid stars and on the existence of the sqm phase inside the star. using a quasi - particle approach, we show that the presence of medium effects increases the energy per baryon for sqm and therefore makes thesqm phase energetically less favorable.    the physical reason for this is the increase of the effective quark masses in medium from about normal nuclear matter density@xmath0 to the order of @xmath1 achieved in the center of the star which is due to the interaction of the quarks with the other quarks of the system. by using the hadronic
the frenkel - kontorova model ( fk ) of glassy system is widely used in the solid state physics to get insight on generic properties of noncommesurate systems.   recently our numerical study @xcite of the original fk model in the pinned phase has shown, that the ground state ( gs ) of the fk chain has some well defined hierarchical structure, which particular detailes are determined by number properties of the ratio of the mean interparticle distance to the period of the external field.. we put our attention to the striking fact, that in the pins phase of this model there are some particles, which positions exponentially close to bottoms of wells of the outside potential : corresponding external force acting to such particle is extremely close to zero.    obviously, in static equilibrium each of these particles can be considered as some dummy " glue " that only couples two adjacent parts of the chain, which ends has almost identical ( exponentially close ) tension forces. in this way   one gets an hierarchically ordered set of brick species @xmath2, which consist of 2 particles inside a single well, and 4 particles ( two pairs in two adjacent wells ), which consists of 4 particles
the permitted o lines at 1304, 8446, and 11287   are common features in agn ( active galactic nuclei ) and have been used to study the physical properties of blr ( broad - line region ) clouds.   it is thus not clear whether the properties of the o line emission found in low - luminosity agns can be applied to quasars. in this study, we present the ratios of the three o lines of the quasar pg 1116 + 215 at z=0.176, including the redshifted o@xmath18446 and o @xmath111287 lines, which were obtained using the longslit of flamingos ( florida multi - object imaging near - ir grism observational spectrometer ; @xcite ) on the kpno ( kitt peak national center for space and electromagnetic observables ) on a near - infrared ( nir ) spectrum of pg 111 6 + 215 with a photon flux ratio of 0.9  1.8/1.8@x Math9.    the results show that the ratio of the photon flux between the red- and blue - shifted o @Xm18446 lines is
the existence of exotic baryons containing four quarks and an antiquark in their lowest fock component has now been confirmed by the observation of a narrow peak at 1.54 @xmath5 0.01 gev/@xmath6, called @x Math0, as an @x maths7 baryon resonance in the photo - production from neutron @xcite.   this has been followed by the experiment of other narrow resonances @xMath2 and @x math10 at about 1862 mev, from which @x mathematics2 is interpreted as another pure exotic member of an su(3 ) flavour antidecuplet.    the purpose of this letter is to perform dynamical calculations of all the members of the antide cuplet to which @ xmath26 and @Xmath27 are supposed to belong. 	 the results show that the theoretical model @xmatrix is a natural extension of the one - gluon exchange model ( colour - spin interaction ) used in the previous work on @xaite, where the heavy antiquark is replaced by a light quark and the quark - quark interaction is assumed to be a flavour - spin structure. for the
the perturbative qcd factorization approach is a generalization of the naive parton model  @xcite  for the calculation of transverse momentum corrections to a variety of moderate and large hadronic cross sections.   it is based on the assumption that the nuclear enhanced high twist corrections to the deeply inelastic lepton - hadron scattering ( dis ) cross sections are fully integrated into the integral of the qcd dynamics by integrating out the two collinear limits of qcd, which are the lowest order and leading twist corrections. here   we show that the integration of these corrections leads to a more robust and accurate calculation of the transverse degrees of freedom of the dis cross sections than the single and double inclusive distributions accessible to @xmath34 at leading twist using the same methodology.
we find the confinement potentials that maximize the overlap of the wave function of a few electron quantum hall droplet with the laughlin state at @xmath4 @xcite, and the moore - read state on the lowest landau level ( lll ) and on the second lowest landausu level ( sll ).   the latter is obtained by applying the landau levels raising operator to each electron coordinate in @x Math10 and assuming the lowestlandau level of both spin types completely filled and inert.
we present a set of self - similar solutions for the steady - state structure of a magnetized, self - gravitating disk for which the effect of the magnetic field is taken into account.   the model is based on an isothermal equation of state and is assumed to be self - regulated at a condition of approximate marginal jeans stability. in the absence of a central point mass, the self - like solution corresponds to a flat rotation curve, while the disk has a fixed opening angle. using numerical simulations,   we show that the magnetic fields inside and outside of the disk are self - consistently self - consistent when the effects of the external magnetic field are studied in a phenomenological way.    the results show that both the vertical and radial magnetic fields are dominated by self - gravity in the case of a well - regulated self - gravitational accretion disk.
the abundance distribution of stars in the galactic halo is a very important parameter for understanding the formation and chemical evolution of the galaxy.   the existence of a radial metallicity gradient in the galaxy is well established, but there is considerable disagreement about whether there is an intrinsic abundance gradient in this region. to address this issue, we have used a combination of spectroscopic and numerical simulations to investigate the presence and size of the galactic abundance gradient using a large - area survey of the northern and southern halves of the Milky Way. from these simulations,   we find that the galactic stellar halo has a radial abundance gradient of about @xmath16 dex kpc@xmath17 for most of the elements, which is in good agreement with the results of several previous studies. however, the magnitude of the gradient is much larger than the average observed in the disk and halo by ~1.5 orders of magnitude ( p<0.05 ).    the presence of the gradients is also supported by the fact that the distributions of the different elements in the halo are not significantly different from those in the thick disk. on the other hand, our results show that the distribution of the central bulge
a comprehensive determination of the rich energy spectrum of the confined chromoelectric flux between static sources in the fundamental representation of @xmath0 was reported earlier  @xcite for separations r ranging from 0.1 fm to 4 fm.   the excitation spectrum clearly contradicts earlier claims @xcite on the simple string interpretation of the linearly rising confining potential and the level orderings and approximate degeneracies of the gluon excitation energies at large r match, without exception, those expected of the goldstone modes which are associated with the spontaneously - broken transverse translational symmetry. a detailed test of the strong coupling spectrum in su(2 ) for d=3 lend further support to the above summary of the earlier findings.
we present a high - resolution spectroscopic atlas for the @xmath6 band.   we obtained spectra of 20 mk - classified stars ranging in spectral type from f through m and in luminosity class from i   v with nirspec @xcite on keck ii between 2001 and 2009. using the reduced one - dimensional spectra, we identified a grid representing each of the four spectral classes ( f, g, k, m ) and three luminosity classes ( i - I - i, iii, iv ). to complement existing moderate resolution catalogs in the@xmath3, @x Math4, and @x math5 bands, we present here a high-resolution infrared spectral atlas that covers the entire range of spectral types and the full range of luminosity groups.    we also present a table of identified absorption features and the resulting atlas of spectral lines. in section , we show relevant atomic data and illustrate as well as discuss line sensitivity to stellar effective temperature and surface gravity.
we investigate the thermal conductivity of diamond nanowires ( dnw )@xcite by molecular dynamics simulation using the tersoff and brenner empirical inter - atomic potentials.   we show that the thermalconductivity of thicker dnw decreases with increasing temperature due to phonon phonon scattering ( pps ), yet does not depend on temperature in narrower dnw where surface scattering is important. our simulation discloses a highly anisotropic heat transport in dnw along  growth direction, which is about five times higher than that of  growth directions. by performing lattice dynamics analysis for dnw  , we believe that this anisotropy is originating from anisotropic group velocity of acoustic phonon modes in dwin along three different growth directions.graphical abstract
spontaneous parametric down conversion ( spdc ) is one of the most popular methods used to generate heralded single photons as well as entangled photon pairs.   the main parameters that control the collection efficiency of photon pairs are thickness of the crystal used for down - conversion, spatial walk - off, and mode field diameter of the optical fibers effectively imaged onto the crystal plane. here  , we study the effect of pump focusing on the coupling efficiency of biphoton coupling pairs obtained in a non - collinear spdc process experimentally. under tight pump focusing conditions,   there is a significant decrease in coupling efficiency with the focusing parameter of the pump beam compared to those under loose pump focusing. using the matching of conditional optical modes of down - converted photons, we show that a loosely focused pump beam and a thin crystal are the best pre - detection conditions for the effective fiber coupling of entangled photons, as the former reduces the effects of spdc ring asymmetry and the later reduces the walk -off effects inside the crystal.. we also verify that the role of collection mode diameter on mode coupling to the fibers is more significant in tight pump focus than in loose pump focus.
the corrispondenza of curry - howard is a new method for the automatic verification of the verifica of programmi in the sistema nuprl @xcite.   the aim of this article is to review the current state of the art in the field of computational linguistics, and to discuss the possibility of developing a system that can be used to automatically detect the correttezza of a given term in a set of results.. the method is based on the use of a series of logistic regression models, which are derived from the most recent work by g.j.woeginger ( http://www.cbi.nlm.nih.gov/pubmed/content/10.1111/j.1741-7007/wong.2011.004926/crcr ), and it is designed to allow the user to specify the type of data to be stored in the same way as the original data, so that the algorithm can be easily reanalyzed at any stage of the processing process. with the help of a web - based tool,   it is possible to identify the exact location of the origin of a term in the
we investigate the critical behavior in ensemble of @xmath0 torus knots and a five - dimensional sqed with the chern   simons term at the level one.   we derive an explicit expression for the free energy in the random walks problem for the " area+length+corners " statistics, which provides the very nontrivial phase structure in the three - dimensional space of fugacities. using the results of the susy gauge theory, we interpret the generating function of ensembles of torus knot types as the weighted sum of instanton contributions to the particular observable in 5d sqed and analyze the structure of corresponding generating function.
the spatial evolutionary prisoner s dilemma games ( sepdg ) are a simple version of the two - player matrix games where the players income depends on their simultaneous choice between two options.   the first numerical investigations have shown that the cooperation can be maintained by very simple strategies in the iterated games @xcite, which are started from an initial set of strategies, which defines the player s decision in the knowledge of their previous choices. here   we investigate the evolution of the strategy " always cooperate " and the so - called " always defect " in the presence of defectors using a mathematical model of the spatial evolutionary Prisoner s dilemmas. to study the emergence of mutual cooperation among selfish individuals, we introduce some simple evolutionary processes without assuming intelligent players ( who are capable of finding the best strategy if it exists ). for each player,   his income is determined by the choice of either defection or cooperation with the other player. as a result   this situation creates a dilemma for intelligent players as mutual cooperation would result in higher income for each of them than mutual defection does. in the simplest evolutionary models the worst player adopts the winner s strategy round by round. despite of its simplicity
the generation of pure nonclassical states of light is one of the most important goals of optical quantum information science.   spontaneous parametric down - conversion ( spdc ) is a nonlinear process that converts high - energy photons into pairs of lower energy photons, which are correlated in frequency and are described by a  joint spectral amplitude _ ( jsa ), which is determined by the properties of the incident pump field and the material property of the nonlinear crystal used to mediate theDown-conversion process. here  , we introduce a method for controlling the shape of the jsa at the source using quasi - phasematching techniques. with this method,   the phase - matching function can be manipulated by manipulating the orientation of the birefringent material domains in the grating while keeping the widths of each domain fixed. as a result, the resulting nonlinearity profile can be almost arbitrary and can be tailored to suit the needs of the particular application.
the alice detector at the lhc will be the next generation facility for exploring the features of hot nuclear matter.   the goal is to create a deconfined quark gluon plasma ( qgp ) for a few fm/@xmath0 and to study its properties. in the following   we discuss some of the possible approaches to this goal.
the proliferation of mobile devices and the surge of a myriad of multimedia applications has resulted in an exponential growth of the mobile data traffic. in this context, wireless caching has emerged as a powerful technique to overcome the backhaul bottleneck, by reducing the back haul rate and the delay in retrieving content from the network. in @xcite,   a novel system architecture named femtocaching was proposed.   it consists of deploying a number of small base stations ( bss ) with large storage capacity, in which content is stored during periods of offpeak traffic and the mobile users can then download the content from these bss, which results in a higher throughput per user. here, we consider the scenario where content is encoded using a maximum distance separable ( mds ) code and stored in the mobile devices, which arrive and depart from a cell according to a poisson random process. for this scenario, we derive analytical expressions for the download delay and show that mds - encoded distributed storage ( ds ) can significantly reduce the delay with respect to the case when content is solely downloaded from the bs.
in the recent paper @xcite we determined the spectral type of the laplacian on the schreier graphs describing the action of grigorchuk s group on the boundary of the infinite binary tree and showed that it is different in the isotropic and anisotropic cases.   our investigation provides a surprising link between discrete schrdinger operators with aperiodic order and the substitutional dynamics arising from a presentation of the group by generators and relators found by lysenok@xcite. here   we review its combinatorial properties and carry out a detailed study of the factor map to its maximal equicontinuous factor, which is the binary odometer. this factor map is proven to be one - to - one everywhere except on three orbits, and this in turn can be linked to the phenomenon of pure point diffraction which is at the core of a periodic order.
this paper is a companion paper of two companion papers, one dealing with robust control of switching systems and the other with reset control strategies for fractional - order hybrid systems.   the latter is based on the idea of coupling two different distinct branches of research, fractional calculus and hybrid systems, into a synergistic way, which is believed to give additional flexibility and help the system designer, taking advantage of the potentialities of both worlds. in this paper,   two types of such techniques are reviewed : robust control for switching systems (  ) and reset control strategy (  ), respectively, and analysed using the theory developed for fractionsal - ordered hybrid systems in part i @xcite. experimental and simulated examples are given to demonstrate the effectiveness of the proposed strategies.
positronium ( ps ) formation in ne, ar, krypton, kr and xe has been determined by two experimental groups @xcite.   the two sets of data are in fairly good agreement, especially at lower energies. however, recent distorted - wave born approximation ( dwba ) calculations overestimate the cross sections by a large factor, ranging from 1.6 in ne to 3 in xe, while the overall energy dependence of the dwba cross sections is in reasonable accord with experiment. in this paper   we perform 1st - order and all - order calculations of ps formation from valence and subvalence subshells. using many - body perturbation theory, and neglecting the interaction between the outgoing ps and residual ion, we calculate the ps - formation amplitude and cross section for each of the noble gas subshelled atoms. as expected, the most important contribution of the subvalenced electrons to ps formation is the high contributions of the positron partial waves, which are spherically symmetric and make it harder for the positrons to bind and move away with an electron. when the interactions between the incoming positron and the residual ion are small, the
index coding, introduced in @xcite, considers the problem of efficiently broadcasting a number of messages available at a source, to receivers that already possess some prior knowledge of the messages.   the most widely studied class of index coding problems is single unicast index coding, where each receiver demands a unique message for each one of the @xmath0 messages being encoded. here  , we show that rate @x Math2 is achievable in a given index coding problem under certain conditions on the topology of the alignment graph and conflict hypergraph of the index code problem.    the main result is based on the properties satisfied by the interference alignment and conflict graphs obtained from the interference structure of the problem, which are shown to be sufficiently different from those used in the previous work on rate@xmath2 feasibility presented in @xaite. using these parameters, we present a construction of an index code for groupcast index coding cases where the interference at the receivers is as ` aligned'as possible ( in order to reduce the amount of linear independence between the precoding matrices required, i.e. to increase the rate ) while satisfying the receiver demands.
we present a coding theoretic approach for evaluating the accumulate distribution of the minimum - cut capacity of weighted random graphs.   the basis of the analysis is the correspondence between the cut space of an undirected graph and a binary ldgm ( low - density generator - matrix ) code with column weight 2. in this paper, we focus on a weighted version of erds - rnyi random graph ensemble @xcite. to obtain an insight for the statistical property of the maximum flow for such random networks, it is natural to investigate the statistical properties of a random graph ensembles. here  , we show that the network coding capacities of weighted unweighted graphs concentrate around the expected number of nearest neighbors of the source and the sinks.
we analyze n - body / smoothed - particle hydrodynamics simulations of galaxy mergers to quantitatively study metal redistribution due to merger - induced gas motions.   we find that the average nuclear metallicity of the merging galaxies is significantly lower than that of the corresponding galaxies of similar mass, and that the radial metal gradients are more intense than those in unbarred spirals. these results are relevant to the formation of ultraluminous infrared galaxies ( ulirgs ) and qsos, which are thought to arise from such a merger.
we study the quench dynamics of a bose - einstein condensate ( bec ) under the synthetic spin - orbit coupling ( soc ) that has recently been realized experimentally at the national institute of standards and technology ( nist ).   we adopt a self - consistent bogoliubov approach to model the dynamical process, which is equivalent to applying the time - dependent bogoliubski - de - gennes equations. in the long - time limit,   the system evolves into a steady state in the absence of soc, which features a stationarycondensate fraction and an oscillating momentum distribution. as the ground - state phase and many - body correlations depend sensitively on the inter - atomic interaction, a frequent theme in quench studies is investigating the system dynamics following a sudden change of inter -atomic interaction strength. here  , we show that while sudden changes of su(2)-invariant interaction strengths can lead to large Condensate depletions, they typically give rise to a much smaller condensatesate depletion. furthermore, if the soc strength is changed by controlling the laser strength, the steady - state fraction of the steady state is found to be more stable than the steady
the study of ultra high energy cosmic rays ( uhecrs ) and neutrinos is a high priority in astroparticle physics.   they are routinely detected through the extensive atmospheric showers ( eas ) they produce when interacting in the atmosphere. despite the recent advances in the measurement of the flux of uhecr   @xcite, their primary composition remains unknown, and this is one of the main obstacles to Extracting precise conclusions on their origin. here   we review the current state of the art in the field of radio - based detection of u hecrs and uhe@xmath0s in ice and salt domes using a combination of simulation and experimental techniques.
the premetric program in physics was first clearly spelled out by friedrich kottler in 1922 in two papers on " newton s law and metric" and on " maxwell s equations and metric ".   we will discuss the two papers in a modern formalism and show that the premetrics are not as well grounded as the metric. in relativistic theories of gravity,   the prematric program leads to a better understanding of the interdependence between topological, affine, and metric concepts, that is, between those concepts related to the surgery of a manifold, to parallel transfer, and to spatio - temporal distances.
the multiple scattering ( ms ) of light is a phenomenon that affects the shower images of extensive air showers of high energies ( @xmath1 ev ).   it occurs when photons emitted by the observed shower element undergo scattering in the atmosphere on their way from the shower to the detector, causing an attenuation of the light flux arriving at the detector and a smearing of the image. here   we present a new approach to calculate the shower data in the multiply scattered light, so that this effect could be allowed for ( subtracted ) when determining the shower primary energy from the photomultipliers ( pmts ) signals. using a combination of monte carlo simulations and analytical techniques  , we show that the number of ms photons produced by the shower can be calculated as a sum of the photons scattered only once ( the first generation ), of those scattered two times ( the second generation ) and so on and calculate separately the angular and temporal distributions for each generation. if the viewing angle of the shower is large enough then the arriving ms light contains not only the fluorescence but also the cherenkov light, which has to be subtracted from the total fluorescence flux. for smaller viewing angles
the accretion on to the neutron star in be / x - ray binaries is considered to result from the interaction between the accreted material from the circumsteller disc of the be star and the rotating magnetized neutron star @xcite.   the accretion disc is also indicated to exist between the outbursts in several systems ( e.g., a0535 + 26 ), and some even show quasi - periodic oscillations ( qpos ). here  , we present simulations of the accrete flow around the neutron stars in be/x - ray binary systems, using a three - dimensional smoothed particle hydrodynamics ( sph ) code that simulates the mass transfer from the be - star disc to the neutrally captured particles. for each system,   two types of accretion processes are simulated : the direct accretion regime and the quiescent state. during the directaccretion regime, the accreting material is dense enough to make the magnetospheric radius smaller than the corotation radius, which causes a bright x - rays emission. in the quyingcent state, the collaterals are in quiescence ( the propeller regime ).
the gaia cornerstone mission by esa will record during its 5-year lifetime an average of @xmath2100 spectra for each of all the stars brighter than @x Math317.5 mag ( @x math4 objects ), over the wavelength range 84808740 and at a resolution 10000@xmath5 20000.   we have identified and calibrated a family of diagnostic line ratios that provide good estimate of temperature ( spectral type ) and surface gravity ( luminosity class ), built on the ratio of equivalent widths. to _ blend 8680 _ contribute mainly lines of fei, si and ni, and the extremes for equivalent width integration extend from 8678.0 to 8681.6 , to fully cover the line wings ( even if including several weak metallic lines ). these ratios are used to calculate temperature sensitive indicators for supergiant, giant and dwarf cool stars, as well as surface gravity sensitive ones for the solar neighborhood stars.
we introduce a novel axiomatization of electrical positroids, motivated by the grassmann - plcker relations, and prove the following : a set @xmath6 of circular pairs is the set of positive circular minors of a response matrix if and only if @x Math6 is an electrical positroid.   we also investigate the connections between electrical networks and other positivity phenomena, including positivity tests for response matrices and cluster algebras.
cold dark matter ( cdm ) theory predicts that a large population of completely or almost completely dark " galaxies " should be present in the milky way. here   we propose an observational test of this scenario. in the early galaxy,   many globular clusters are expected to have surrounded the milsky way.   galactic tidal forces have been destroying these objects, and of the initial population of a few hundred objects, only @xmath8 remain. in a static potential, as a low - mass stellar system, such as a globular cluster, loses progressively more and more mass to tidal forces, it develops long tidal tails that closely follow the orbit of the globular clustering. for the first time, we show that these tails can be observed in the universe, and that they are strongly correlated with the radial velocities of the high velocity clouds that pepper the sky. at the same time, our results also show that the density of the cloud population is much lower than expected from cdm theory, and suggests that these clouds are not of cosmological origin.
we study the thermal corrections of quantum electrodynamics ( qed ) to electron selfmass, charge and wavefunction in a hot and dense medium using the renormalization scheme of qed at finite temperature and density ( ftd ).   we find that the first order thermal corrections to these parameters are due to the electroweak corrections of the background density effects through the chemical potentials of the neutrino mediators w and z. the second order corrections to the qed parameters are related to the beta decay rate and the helium abundance in the early universe. for this purpose  , we consider previously calculated relationships of electron mass with nucleosynthesis parameters, such as beta decay rates and helium abundances, in the primordial universe and in the stellar cores.
prismatic dislocation loops play an important role in influencing the macroscopic mechanical properties of materials, in particular ductility and fracture toughness in metals.   it is widely believed that vacancy clustering is a precursor mechanism to the nucleation of prismatic loops in quenched metals. here   we employ a real - space formulation of orbital - free density functional theory and the quasi - continuum reduction technique to conduct electronic structure calculations on multi - million atom systems using the wang govind carter ( wgc ) orbital -Free kinetic energy functional for aluminum as a model system. by computing the binding energies of divacancies in aluminum, we show that the energetics of vacancy clusters containing self - interstitals are significantly higher than those of quad - vacancy clusters formed from divacancy clusters. among the planar   vacancy clusters, those lying in the \{111 } plane had the highest binding energy. while the hexagonal vacancy cluster has a very large relaxed binding energy and the atomic structure closely resembles a collapsed prismatic dislocated loop, the x - ray diffraction results indicate that the formation of these clusters is much more rapid than previously thought.
we present a comprehensive framework for the representation and analysis of complex surface forces as they are measured by dynamic atomic force microscopy ( afm ).   we focus on the most common modes of dynamic afm : amplitude - modulated afm ( am - afm, n = 2 ) and frequency -modulated af m ( fm - afms, n=2 ), which can be considered as narrow frequency band methods@xcite.    we explore the fundamental limit of force reconstruction with narrow band dynamic afM at fixed probe height and show how minimal assumptions allow for a quantitative reconstruction of the tip - surface interaction.. the force between the tip and surface is usually represented as a scalar function of the probe position only and represented by simple force curves. however, the contribution of dissipative forces to the force spectrum is often not taken into account in the standard force curve representation. here  , we show that the maximum force reconstruction can be achieved by using only the first flexural resonance frequency of the cantilever beam excited by the external drive force from the sample surface.
the relative proximity of the galactic center ( henceforth gc ) provides a unique opportunity for " close - up " study of processes that are expected to be crucial in the formation of galaxies and black holes, yet remain essentially unobservable in more distant galaxies.   recent advances in telescope technology have enabled us to resolve individual stars in the crowded gc environment, and the development of adaptive optics has allowed determination of both velocities and positions of such stars to be made with ever - increasing accuracy. here   we investigate the effects of the stellar mass function on the evolution of a mass - segregated ring of stars orbiting a massive central black hole, and use observational determinations of the star orbital parameters to constrain the mass function of the Star Ring. using numerical simulations of the system, we find that the distribution of eccentricities can tell us about both the upper and lower ends of thestarring mass function, and discuss the consequences of this result for theories of star formation in the gc environments.
the aim of this paper is not only to describe the thermal behavior of a heating device, but to establish a methodology for ovens design considering the temperature evolution for different products and process.   the schematic oven is composed by a cooking chamber which is thermally insulated with a high thermal resistivity material ; inside this chamber the material to be heat treated is placed. both material and chamber are heated simultaneously during oven operation with internal or external energy source. in order to obtain simplest model we will set this heat flow as constant, @xmath10 ( from temperature @x Math11 ). after the cooking process the cooling part follows with curve @x math13, then the temperature may be described by a curve like @x maths15, at the end of cooking the thermal energy flow to the oven is canceled, and the cooling of the oven and the products start ( curve@xmath15 ). with this   it is shown that if the operation temperature was not specified ( in other words @xMath17 ), and an energy is introduced into the oven, the thermal process starts following the temperature curve @Xmath5 until time @x mathematics4, and later, it will continue the curve @ xmath19.
the nonlinear gross - pitaevskii equation @xcite is used to describe a hamiltonian @xmath0 symmetric quantum system with gain and loss effects in the mean - field limit.   it is shown that the system exhibits a new type of bifurcation at a third - order exceptional point, i.e. a branch point at which both the eigenvalues and the wave functions are identical, and becomes complex and complex conjugate. for the same strength of the gain / loss contributions the broken states emerge from one of the @x Math0 symmetrical states in a pitchfork bifurscant b if the gain/lose contributions are lower than those at which the corresponding @x math0 symmetry states vanish.
the origin of charged particles in the interstellar medium remains an enduring question in astrophysics.   the arrival directions of these particles are highly isotropic and are expected to be imprinted upon the distribution of arrival directions as observed on earth by the scrambling action of the encountered magnetic fields. during the past decade  , multiple observatories located in both hemispheres have reported significant observations of large - scale and small - scale anisotropies in the tev - pev energy band.    these results have challenged the long - standing description of cr propagation in terms of a typical spatial diffusion process from stationary sources located preferentially in the disk of the galaxy, leading to a dipole moment only in the direction of the cr gradient and with an amplitude steadily increasing with the energy.. at the highest energies, searches for clustering of arrived directions as well as searches for correlations between cr arrival directions and the positions of nearby extragalactic objects are the best suited tools in attempting to decipher the origin of these particle.
the large hadron collider ( lhc ) has been running since 2009.   the two mayor experiments, atlas and cms, have discovered a new particle compatible with the higgs boson of the standard model, with a mass of 126 gev @xcite. in this article   we will discuss the results of the searches for supersymmetry performed by the two experiments.
the nodal set is a collection of hyper - surfaces on a smooth connected compact riemannian manifold where the eigenfunction of the free stationary schrdinger equation vanishes.   it is a well - known property of wave functions that the nodal volume is larger with increasing energy. in this work   we investigate the distribution of nodal volumes for two models of a regular shape with separable laplacian and integrable ray dynamics ; * the cuboid and * the boundary adapted planar random wave model. using a statistical approach we show that the rescaled nodal space is distributed statistically for both models. for the Cuboid,   the nodalset is smaller than for the boundary adjusted model but the difference is not statistically significant. by taking into account the existence of discrete nodal points on the manifold, we find that the size of each nodal point is proportional to the number of steps in the continuum evolution of the wave function. for The boundary adapted model   these results are consistent with the sturm - liouville oscillation theorem.
the behavior of a particle diffusing in the presence of traps is studied by means of the analysis of the density of eigenvalues of the transition probability matrix @xmath3 which describes the diffusion process.   the results show that the properties of the diffusing particle are dominated by the existence of large trap free regions which have a finite ( though small ) probability of occurence. for the case of uncorrelated traps,   this behavior is modified when we introduce long range correlations in their positions @xcite. in the equivalent scalar elasticity problem, the correlated traps map to the clamping of sites with a correlated distribution. in this sense  , the present problem extends the so - called _ fractino _ problem where a fractal boundary of an otherwise nonfractal object is clamped to the case where the bulk of the substrate is itself a fractals.. the stretched exponential form of the stretch exponent characterizing the long time behavior of@xmath2 is found to be similar to the poissonian trap distribution but with a substantially different stretch exponent.    we show this behavior from the analysis and study the finite size scaling of the largest eigenvalue of @x
we present a combination of the approximately globally convergent method of @xcite with a finite element method ( fem ) for the numerical solution of a 3-d hyperbolic coefficient inverse problem ( cip ).   we consider the problem of reconstruction of refractive indices or dielectric constants of unknown targets placed in a homogeneous domain from blind backscattered experimental data. given a certain function computed by the technique of@xcite, the fem reconstructs the unknown coefficient in an explicit form. as a result, we can reconstruct refractive coefficients and locations of targets. to obtain better shapes, we use a locally convergent adaptivity technique.
the baikal neutrino telescope is being deployed in the siberian lake Baikal, about 3.6 km from shore at a depth of 1.1 km @xcite.   the central mission of the project is the detection of extraterrestrial sources of high energy neutrinos using the optical module ( om ) of the phototube _   quasar-370_, which consists of an electro - optical preamplifier followed by a conventional photomultiplier ( pmt ) and a photoelectron scintillator. to achieve this, the om has to be equipped with a large - area, large - acceptance light detector with single photoelectrode resolution. here   we describe the design and operation of the components of the om, most of which have been developed within the collaboration of the bmc / usa and the university of california at san diego.    the operational principle of two pmts switched in coincidence is discussed, and results from the different methods of om calibration are presented. for the long - term operation underwater,   some selected results of the telescope operation are given.
@xmath0c is one of the typical examples where the cluster and shell - model - like aspects coexist.   the @xmath2-cluster structure is favored in @x Math0c and is considered to develop in excited states. here, we have used the method of antisymmetrized molecular dynamics(amd ) to describe the energy variation after spin - parity projection(vap ) in the ground state of @x math0c using the two different kinds of nature, cluster andshell - model -- like aspects. for the excited states,   vap calculations have been performed using the same framework as the cluster model calculations but the dissociation of the clusters has been incorporated into the amd model. by combining the results of the cluster models with those of the shell model calculations, the density functional theory ( dft )   has been used to study the behavior of the excited cluster states in the region around @x maths0c.. the results show that the excited clusters are characterized by the formation of a double sub - shell closure of the @Xmath4 shell in the coupling picture, and the shell competition between the low - lying and high - lying states.
the supersymmetry lagrangian of the kaon system @xcite is a soft phase in the standard model ( sm ).   the phases affect much more than cp violating observables, and it has been argued that all cp violating effects could be explained by these susy soft phases. in this paper   we illustrate how the presence of phases affect observables and can be measured in gluino production and decay at fermilab and lep.
perturbative quantum chromodynamics ( pqcd ) has been established as an extremely successful theory to describe phenomena related to scattering reactions off hadrons at large momentum transfer.   however, there are quantities of non - perturbative nature which can not be described by perturbation theory, e.g.  the bound states of qcd. here   we present a factorization theorem which enables us to separate these quantities into a set of well - defined, gauge - invariant ( i.e.  observable ) and process independent quantities. in this way   they can be expressed by matrix elements of parton operators between hadron states. using deep inelastic lepton nucleon scattering ( dis ) as an example  , we show that the leading twist contribution to dis is a simple annihilation of quarks and antiquarks to produce a virtual photon, which then scatters off one quark from the nucleon. for the drell yan process also afactorization theorem holds which gives the lead twist contribution as a simple annihilation of quacks and antiquarians to produce two lepton pairs.
we investigate the mechanism of catalyzed symmetry breaking in the context of the @xmath0 gross - neveu model @xcite in curved spacetime using functional renormalization ( rg ) methods.   we find that the effective dimensional reduction and the enhancement of the density of states in the ir are directly related to the behavior of the rg fixed points as a function of the magnetic field. from this rg viewpoint,   symmetry breaking arises as a consequence of the fact that the coupling value required for criticality becomes arbitrarily small as a result of the curvature ( the catalyzer ). by means of a pseudo - critical coupling, we show that any finite value of the fermionic interactions ultimately becomes supercritical, typically driving the system towards the ordered phase.
we study the effect of model dependence on the nucleon - nucleon scattering phase shifts and deuteron properties of two - body interactions in low energy nuclear systems using a renormalization group decimation and integration of the ambiguous high momentum components of the realistic interactions.   the resulting effective low momentum potential, called @xmath0, is independent of the particular input model for the one - pion exchange interaction ( ope ) at long distance, but not of the intermediate and short - range parts.
we investigate transport asymmetries in one - channel y - junctions of quantum wires with three impurities.   we show that a stronger diode effect can be achieved in such systems than in a linear luttinger liquid conductor and rectification is possible even in the case of symmetric point scatterers. at the same time, changing geometry may increase asymmetry and hence the rectification current.
anomalous diffusion has been observed in systems as widely varied as plasma flow, surface growth, and financial markets.   a general framework for treating superdiffusive systems is provided by the nonlinear fokker - planck equation, which is associated with an underlying ito - langevin process. here   we show that this approach seems to accurately describe high - frequency intra - day price changes for the s&p500 index.
the metal - poor halo star ( ) was chosen as one of the targets for the first commissioning of uv - visual echelle spectrographs ( uves ) on the eso vlt ut2 ( kueyen ) telescope.   the aim was to test if uves can supply high quality spectra suitable for a determination of the lithium isotope ratio in stars, which is an important issue in observational stellar astrophysics and cosmology. using both 1d and 3d model atmospheres   we analyze a high resolution, very high @xmath1 spectrum of g271 - 162, obtained during the commissioning with uves on vlt / kue yu on october 11 - 13, 1999, using both hydrodynamical and hydrostatic model atmosphes. from the 1d model atmosphere   it is found that the mass of the star is reduced by about 50% due to the formation of a convective line asymmetry introduced by the increased width and asymmetry of the  670.8 nm doublet introduced by its isotope shift ( 0.16  = 7.1 ).    since the line is not resolved, the derived
the charm quark ( cq ) is an efficient probe for the study of quark gluon plasma(qgp ).   the transport coefficients of the cq in the qgp are sensitive to the interaction of the probes with the medium and hence estimation of the various transport coefficients by using cq as a probe is a field of high contemporary interest. in the present work, we estimate the drag, diffusion and shear viscous coefficients of qgp by estimating the transverse and longitudinal diffusion coefficients of cq undergoing radiative loss by emitting gluons while propelling through the Qgp.    the effects of the radiative transport coefficients on the equilibrium distribution of cqs are also discussed.
we propose that quantum features in quantum mechanics originate from a dissipative process which affects all physical objects.   we speculate that the atomistic structure of spacetime itself is responsible for effects which are attributed to quantum mechanics, typically operating at length scales very much larger than the planck length. with these findings in mind, we discuss aspects of a dynamical transition from classical to quantum behaviour, assuming that : ( 1 ) quantum features originate from dissipation, i.e., a fundamental information loss mechanism ; ( 2 ) the number of atoms in an atomistic spacetime changes dynamically ; ( 3 ) the existence of a constant number of causal relations between a given object and its environment ; ( 4 ) the evolution of its causal relations with a continually changing number of " atoms " is compatible with the conservation of probability ; and ( 5 ) matter degrees of freedom are continually " measured" by the evolutionof spacetime.
the yields and velocities of the heavy residues and fission fragments from the interaction of @xmath0au ( 20 mev / nucleon ) with an intermediate mass nucleus,@xmath1zr, have been measured by using a high resolution spectrometer / detector system.   the results show that the yield distributions of the evaporation residues from peripheral collisions are very similar to those of the traditional dissipation collisions. however, the velocity distributions of some of the projectile - like fragments, i.e., the proton - rich fragments of the au + zr reaction, are very different. in this paper, we present evidence indicating that these fragments are formed in " hard " collisions, possibly resulting from very asymmetric fission and/or imf emission. also, the results of the measurements are compared to modern models of the dissipative features of intermediate energy collisions.
the essential resource, entanglement, can be realized with a two - mode squeezed vacuum state.   this state is relatively easy to work with theoretically and is also commonly produced in the laboratory. however, it is not yet suitable for practical use due to the lack of nonlinearity of the optical gaussian operations used to extract the photon - subtracted squeezed state. here  , we present a new method for quantifying the entanglements of the squeezed state, in a way which is independent of external parameters such as the type of input state for the quantum teleportation protocol, the choice of the measurement basis for the bell - type inequality violation, and the signal power of modulation for the dense coding. using continuous variable ( cv ) quantum optical systems,   we show that the entropy of the non - gaussian mixed state can be calculated in terms of the negativity and the logarithmic negativity of the partially - transposed density operator, and that these measures are easily computable numerically with linear algebra packages.
variational principles have a long and distinguished history in physics. apart from global formulations of physical principles, equivalent to local differential equations, they also are useful to approximate problems too difficult for analytic solutions. in recent years   there has been some progress in using classical variational principles ( action principles ) to approximate the motion of classical systems such as classical molecules.   we review recent developments in this area of classical mechanics, although we also overlap with quantum mechanics. in particular we discuss the use of the quantum variational principle for excited states, and the connection to classical action principles.
the accretion of mass in a galaxy is a complex process, involving two processes : either it accretes gas regularly, through internal dynamics, producing radial flows, from gas in the outer parts ( the reservoir could be in the local group ) ; or the accretion occurs in more violent events, galaxy interactions or mergers.   the first process, that will be called secular accretion, can also be triggered and enhanced by the passage of companions, so that the two processus are in fact inter - related. if the gravitational viscous time - scale governing the mass accretion is governing this process, the time - scales for accretion by secular evolution are of the order of a few dynamical times. but   there must exist a reservoir of gas at the center of the galaxy, as shown by the presence of gas warps in almost every disk galaxy observed in high - resolution ( hi ) spectroscopy. here  , we review the evidence that the milky way has accreted mass or has even formed stars, and discuss the relationship between the two processes.
the question of the causal behavior of superluminal propagations has been often debated, in rather different contexts : tachyonic particles ( e.g., @xcite ), field theories ( i.e., k - essence scalar fields, bimetric theories of gravity and quantum induced superlunar propagations ).   we present a general analysis of the causality of these phenomena, focusing on the role of chronology, time arrow and cauchy problem in its definition.  also, we show that the theory of general relativity can not be considered as a causal theory if it assumes that causality should be defined with respect to the chronology induced by the gravitational metric.
the dynamics of grain - scale flows in dry granular materials are well understood under the scope of the so - called kinetic theory @xcite.   however, experimental results have recently shown that the particle - scale dynamics within these shear bands vary with the spatial dimension of the packing environment. here   we introduce non - local effects by postulating a correlation length in the particles displacements which depends on their position within the shear band and show that this can be used to model the flow as a succession of transient fractures allowing the coherent motion of clusters of various sizes. using this approach  , we show that the probability distribution and the force spectrum derived from this model are in good agreement with experimental results.
we propose a method to construct an effective hamiltonian via monte carlo for the quantization of many - body systems.   we use a stochastic basis state to construct the effective hamiltons from transition matrix elements of the transition amplitude and hence the path integral starting from the action. in this way   one can obtain the ground state energy, but also wave functions and the spectrum of excited states. by using the stochastically chosen representative basis states, one can compute the effective Hamiltonian from the transition matrix element between those basis states. as a test case  , we consider a chain of particles with quantum number @xmath2 and a number of low - energy eigenstates ( e.g. 1-d chain of gluons ) and find that the new method works in both cases.
the virtual photon compton scattering ( dvcs ) process is a well - known example of a hard scattering process which is described in terms of off - diagonal parton distributions, where the momentum, helicity or charge of the outgoing target are not the same as those of the corresponding incident particle.   precision data are becoming available for hard scattering processes whose description requires knowledge of these off -agonal ( or skewed ) parts of the process. in this article   we review the main theoretical approaches to parameterise the dvrs process using generalised parton distribution functions ( gpds ) and discuss how they can be used to extract information on the gluons within the proton in a non - forward kinematic case.
we investigate whether @xmath1-symmetry can be utilized as well to explain the observed phenomenon of a tunable passage time for non - hermitian hamiltonians with complex eigenvalues describing dissipative systems, i.e. those for which @x Math1-Symmetry is definitely broken.   we find that the possibility of arbitrarily small passage times results from the nature of the hamiltonian involved in the time - evolution operator and not its @x math1-invariance.
collisions between nuclei with different charge asymmetries may carry important information on the structure of the nuclear equation of state ( eos ) symmetry term in density regions away from the normal value, that may be encountered along the reaction path  @xcite. in this paper   we undertake this kind of investigations by studying isospin transport effects on the reaction dynamics in collisions with impact parameter between 4 and 12 fm.   two systems, with the same projectile, @xmath2ni, and two different targets ( @x Math2ni and@xmath3au ), are considered at incident energies of 52 amev and 74 amev.. the n / z ratio of the two composite systems is n / x=1.07 for ni+ni and n / y=1,38 for ni+.the results show that the asy - stiff eos can be linked to a stronger repulsion in the first stage of the collisions, due to the increased value of the symmetry energy above normal density. however, in proton - rich systems, the larger the impact parameter, the more repulsive the eos becomes. in the symmetric ni + ni system,   the isosp
the decay of local energy for the solution of the wave equation in the de sitter   schwarzschild space - time is studied using the theory of resonances.   resonances are the frequencies and rates of dumping of signals emitted by the black hole in the presence of perturbations. on the one hand   these resonances represent an important hope of effectively detecting the existence of a black hole as we are theoretically able to measure the corresponding gravitational waves. however, the distance of the resonances to the real axis reflects the stability of the system under the perturbation : larger distances correspond to more stability. in this paper   we show that the local energy decays polynomially if we permit a logarithmic derivative loss in the angular directions and exponentially if we allow an @xmath0 derivative loss with respect to the center of the plane. from the results of the work of s barreto   and zworski ( @xcite ) we can describe an expansion of the solution at the origin of the problem in terms of the number of resonance - based local energy decay estimates.
the hermes experiment@xcite is a study of the spin structure of the nucleon which emphasizes on an unambiguous measurement of pion, kaon, and proton semi - inclusive spin asymmetries in deep - inelastic scattering ( dis ).   most of the hadrons produced in hermes  @xcite lie between 2  and 10  gev, a region in which it has not been feasible to separate pions, kaons, and protons with standard particle identification techniques. here   we report the successful use, for the first time, of clear aerogel in combination with a heavy gas, @xmath2, in a ring imaging erenkov ( rich ) detector. this dual - radiator rich detector provides clean separation of pions ; kaons ; and proticles over much of the kinematic acceptance of the her mes experiment.
the low energy concentrator spectrometer ( lecs ) is one of the narrow field instruments ( nfi ) on - board bepposax @xcite.   it operates in the energy range 0.110 kev and has a good spectral resolution at energies @xmath30.5  kev, where instruments such as the solid state imaging spectrometry ( sis ) on asca are not sensitive. to verify the low - energy response of the lecs in - flight,   sufficient data were acquired to enable a detailed study of the low energy calibration of this nfi. for the first time  , we show that the instrumental feature of the@xcite emission is reduced by 15% between 0.40.5 kev after adjustment for changes in instrumental performance between pre - launch ground calibrations and in - orbit operations in a near - vacuum environment.
the cosmic noon is a critical period for galaxy assembly, when the rate of star - formation peaks between @xmath6 and@xmath7.   recent advances in near infrared imaging and instrumental multiplexing capabilities have provided a wealth of knowledge regarding the physical properties of galaxies during this period, the cosmic noon. here   we review the current state of knowledge about the kinematic properties of stars - forming galaxies at this time, with a focus on the role of external processes such as clumpy accretion from the cosmic web and stellar feedback in the formation of low mass galaxies.
we have shown that the expression levels of the gap genes involved in patterning the early fruit fly embryo provide enough information to specify the location of each cell along the anterior  posterior axis of the embryo with @xmath0 precision, comparable to the precision with which pair - rule stripes and other morphological markers are specified.   these results support the idea that biologically relevant information is carried by precisely controlled gene expression levels, so that the function of this genetic network is fundamentally quantitative, down to the accuracy in the encoded variable.
extended far - infrared ( fir ) emission from elliptical galaxies that do not contain large masses of neutral, molecular or optically visible cold gas is observed by the _ spitzer space telescope at 24, 70 and 160@xmath1 m.   the luminosity of the extended fir emission in these galaxies greatly exceeds that expected from normal mass loss from local stars and the internal rates that dust is formed and destroyed by sputtering can be estimated from the frequency of thermal impacts from ions in the hot interstellar gas. to understand the relative role of internal and external sources of dust in elliptical galaxy emission, we describe here new observations of the northern and southern regions of the @xmath10kpc with the_ spitzer probe at 4.5, 6.0 and 8.0 kpc using a combination of our own proprietary data and those of other observables. for most of the galaxies studied,   only small optically thick nuclear dust clouds are observed in the central region of the core, suggesting that dust accumulated in the center of these galaxies from stellar sources in the core is transported out to larger radii by buoyantly rising gas intermittently heated by buoyant rising gas in the outer atmosphere.
the position stability of the laser beam in an acousto - optic modulator ( aom ) is a critical parameter in many applications, especially for dipole traps formed by strongly focused, far off - resonant laser beams  @xcite.   a small change of the beam position can have a dramatic effect on the trap characteristics ( frequency and depth ), thus causing severe problems  . one way to circumvent this problem is to use a single - mode optical fibre after the aom, but this can not be done for high power lasers, such as @xmath3 or ytterbium fibre lasers. in this paper   we report on a simple scheme, adaptable to any aom which strongly reduces the beam displacement, by adjusting the relative power of the radio - frequencies driving the aoms so that the total rf power in the aoma is kept constant. using a tellurium dioxide crystal and a germanium crystal, we test the method with two different aoms in the 1 @xmath2 m and the 10  @x Math2 m wavelength range.
abstractthe recent discovery of up to nine new ultra - faint satellites in the southern sky by the dark energy survey ( des, *???   * ; *????? ) and the detection of three more faint dwarf satellite candidates by the sloan digital sky survey ( sdss ) provide an exciting glimpse into the near future and point to a much larger population of as - yet - undiscovered dwarf galaxies in the local volume.
the magnetic field of the permanent magnet at the american space observatory ( ams ) is a geomagnetic field with a temperature dependence of @xmath2c.   the magnet has a central field of 1.4 kg and contains a silicon tracker that measures the rigidity of charged cosmic rays. in the first 30 months ( @x Math10s )   ams collected primary cosmic ray events, which increase with increasing rigidity becoming constant at@xmath12s above 30gv. by selecting events to be downward going and to have a positive reconstructed track in the inner tracker with charge compatible with @x math13, @x maths14 events were obtained.    the data are presented in the form of a simulation of the measured flux from the magnet to the detector using monte carlo simulations. for the selected sample, the background contributions from protons which are the dominant component of cosmic rays   are not removed in this analysis. 	 the deuteron contribution decreases with rigidity : at 1gv it is less than 2% and at 20gv its value is 0.6%  @xcite. as the number of protons in the sample increases, the
the properties of supersonic hydrodynamic and molecular cloud turbulence, such as power spectra and intermittency indicators, may play an important role in the evolution of molecular clouds.   we investigate the effect of the assumed driving mechanism on the properties of the resulting turbulence using a new higher - order godunov code, athena, which simulates turbulent media with a variety of magnetic field strengths using high - resolution numerical simulations with twenty - five different parameter sets. to date, most results have been computed using a few numerical algorithms, including zeus, the pencil code, the stagger code, and the eno code. here  , we show that the choice of the method for the simulated driving will have an insignificant effect on the results. however, the effects of the driving mechanism are more pronounced when the simulation is performed with a strong magnetic field strength ( e.g.  0.5  kj / cm2 ). by simulating the turbulent medium with a stronger magnetic field, we find that the decay time of the turbulence is significantly longer than that of the fluid with a low magnetic field ; however, this effect is not observed when the magnetic field is weak enough to cause the turbulence to
we compare the dynamical matrix ( dm ) obtained from the generalized random - phase approximations ( grpa ) and the deformation energy method for the crystalline states of the two - dimensional electron gas ( 2deg ) in order to find the range of validity as well as the limitations of the gpra approach.   we first consider the simple case of an isotropic ( triangular ) wigner crystal before tackling the more complex anisotropic wigninger crystal or stripe phase that occurs near half - filling in the higher landau levels. using elasticity theory, we show that although the grpa method gives a good description of the qualitative behavior of the dm as a function of filling factor, its quantitative predictions must be used with caution. by averaging the coefficients of the elastic deformation of the crystals in the hartree - fock ( hfa ), we obtain a dm that compares favorably with the one obtained by computing the deformed state of the crystal in the gpa.
we use a natural force - based vertex model to measure angle - deviations from the force - balance angle of undrained two - dimensional ( 2d ) soap froths in the dry - froth limit.   we find systematic deviations of three - fold vertex angles from the experimental value of @xmath11, consistent with experimentally observed angle deviations for undrained froths. at microscopic scales,   four- and five - sided bubbles have been observed to annihilate directly through processes of side - swapping between adjacent bubbles, but the details of these processes are not well understood. here  , we show that the scaling regime of our model froth is also characterized by macroscopic side - shedding events during the topological rearrangements of the bubble walls and vertices as well as direct annihilation of four- or five -sided bubbles at microscopic scale.
graphical models are used in many applications, and estimating the edge structure of an underlying graphical model is of significant interest.   it is a classical corollary of the hammersley  clifford theorem that zeros in the inverse covariance matrix of a multivariate gaussian distribution indicate absent edges in the corresponding graphical model. in this paper, we establish a number of interesting links between covariance matrices and the edge structures of discrete - valued random variables. using population - level data, we show that it is often fruitful to augment the usual covariance Matrices with higher - order interaction terms. for tree - structured graphs,   the inverse of a generalized covarianceMatrix is always ( block ) graph - structured. for binary variables, however, the inverse can be used to recover the topological structure of the tree. here  , we also establish more general results that apply to arbitrary ( nontree ) graphs, specified in terms of graph triangulations. as we illustrate, our population - levels results imply that minor variants of the graphical lasso and neighborhood regression methods, though originally developed for gaussian data, remain consistent for trees and the broader class of graphical models with singleton separator sets.
the polarized emc effect is a well - known nonperturbative effect of the quark wave function on the nuclear environment, that is, to the nuclear mean fields.   it has been shown recently that this effect can be explained if one takes into account the response of the qw wave function to thenuclear environment and that the same mechanism gives rise also to medium modifications of the polarized quark distributions and structure functions. in this work  , we focus on the predictions for the polarization effect, and briefly discuss extensions to describe transversity distributions and fragmentation functions.
the dynamics of mean - field models have been widely studied as paradigmatic representatives of the important class of systems subject to long - range coupling.   the hamiltonian mean field model ( hmf ) @xcite has often been referred to as the benchmark model for elaborating onto the emergence of quasi - stationary states, hereafter qss, in which particles are trapped in intermediate ( out - of - equilibrium ) states, whose duration diverges with the number of constitutive elements, and which substantially differ from the corresponding thermodynamic equilibrium configuration. here  , we study the free - electron laser ( fel ) dynamics in the context of the colson - bonifacio model for the coupled evolution of the electrons with a co - propagating wave. using the n - body model, we show that the continuum phase transition is ubiquitous in the fel dynamics, and that it can be explained by a consistent intrepretative framework based on the maximum entropy principle, which is fully justified from first principles@xcite. moreover, we find that the existence of this transition is independent of the medium being investigated.
the galactic bulge region of our galaxy hosts a variety of x - ray and @xmath0-ray point sources, including persistent and transient neutron star and black - hole candidate binaries, x - rays, pulsars, bursters, etc.   because of the variability these sources possess on time scales of msec to days ( quasi - periodic oscillations, pulsations,  dips, eclipses, type i and type ii X - ray bursts, orbital variations, flares ), the region never looks exactly the same.  in this paper we describe the first two periods of monitoring performed by the esa fine spectroscopy instrument _ integral_ ( the * inte*rnational * g*amma-*r*ay * a*strophysics * l*aboratory ; winkler et al., 2003 ) during the period from 17 february 2005 to october 2005, whenever the region is visible by _ integral_. one complete hexagonal dither pattern ( 7 pointings of 1800sec each ) in a hexagonal pattern around the nominal target location, each 2@xmath5 apart, is performed during each _ integral _ revolution, or orbit around the earth.
the aharonov  bohm effect is the purely quantum effect which is due to the influence of the vector potential of the impenetrable magnetic vortex on the motion of a charged particle.   the first interference experiment to verify this effect was performed @xcite, and this caused a burst of interest opening a long way of an extensive research both in theory and in experiment. however, it looks rather paradoxical that, whereas interference experiments aiming at the verification of the ab effect were numerous, a scattering experiment aimed at the same was _ never  performed. here   we provide an explanation for this paradox by examining the schrdinger wave equation for the scattering differential cross section per unit length of the magnetic vortex as a function of the dimensionless variable @xmath2 } { \sin^2(\varphi/2),\label{eq1}}. the results of the interference experiment are compared with those of the experimental results obtained by the authors of the original paper@xcite ( see, e.g., http://www.biomedcentral.com/1471-7007/1741-x - ray-scattering-interference-experiment).we find that the exact solution
the symmetry energy of the nuclear equation of state ( eos ) is an essential part of the model of the core collapse of a massive star.   the symmetry energy is used to determine the effectiveness of electron captures on nuclei and free protons during the collapse phase. in the fermi gas model,   this symmetry energy depends on the change of the effective mass parameter @xmath13-mass which scales like@xmath18. here  , we use the shell model monte carlo ( smmc ) to study the temperature dependence of the symmetry power of the eos for finite nuclei at finite temperatures. using the hartree - fock potential introduced by the pauli principle, we find that the value of @x Math4 increases with increasing temperature. as the temperature of the collapse increases, the number of proton - rich nuclei in the core decreases while the amount of neutron -rich nuclei increases. however, when the temperature is reduced to a few mev, the effect of these changes is not significant. furthermore, the increase in the symmetry energies is found to be independent of the rate of decay of the stellar electron and the neutrino - nucleus reactions.
a very - high energy ( vhe ) gamma - ray source with no obvious counterpart in other wavelength has been found with a significant off - set of 3.5 degree from the galactic plane : hess j1507 - 622 @xcite.   this source is detected with an integral flux ( @xmath0 1 tev ) of @x math1 s@xmath3 and a spectrum given by @x maths4 with @x Math5 and a flux normalization of @ xmath6 tev@xMath3   s@Xmath3 @xcites.    for the purpose of this paper a hadronic model involving interactions between high - energy protons with the ambient inter - stellar medium ( ism ) is adopted to investigate the influence of a location at low density environments on the properties of such sources. using the galactic density profile perpendicular to the galactic disk as a proxy for the density of target material,   the Hadronic model is used to estimate the luminosity of the origin of the gamma - rays which is monotonically decreasing with increasing distance from the Galactic plane. when the object is located at a distance of 400 pc from the center of the galaxy the
in cardiac magnetic resonance imaging ( mri ), several slices can be acquired to cover the heart in 3d and at a collection of discrete time samples over the cardiac cycle. from these partial observations,   the challenge is to extract the heart s dynamics from these input spatio - temporal data.   image registration consists in estimating a transformation which insures the warping of one reference image onto another target image. here  , we consider a reasonable interpolation process to continuously map the image intensity functions between two images in the context of cardiac motion estimation and modeling. for this purpose, we present an algorithm to compute a time dependent transportation plan without using lagrangian techniques. by applying the proposed algorithm to a 2d cardiac medical image, it is shown that the results obtained are the solutions minimizing the same energy as the time dependent optimal mass transportation problem.
supermassive black holes ( smbh ) are believed to have been formed within the first billion years after the big bang.   however, it is still an open question how they form and grow to reach such high masses in such a short amount of time. here   we investigate the formation and evolution of a supermassive black hole ( bh ) by performing relativistic simulations of the collapse of a non - rotating supermassive star ( sms ) in the range of @xmath19-@xmath20 with mass > 1.5 times larger than that of the central black hole at the centre of sgr  . the results show that the rate and efficiency of the inflow of gas into the sms depends on the rate of mass accumulation and the mechanism redistributing its angular momentum. if sufficient primordial gas in massive halos, with mass @x Math13, is unable to cool below @x math14, it may lead to the formation of a new supermassive object, which would eventually collapse to form a smbh.
mri plays a key role in the diagnosis and management of acute ischemic stroke and traumatic brain injury.   it exploits ensemble phenomena in which the composition of a sample can be probed by sensing its magnetic properties through radio frequency waves. here  , we review the current state of the art in the field of magnetic resonance imaging ( mri ), focusing on the hydrogen atom @xmath0h as the most frequently targeted nucleus in mri due largely to its biological abundance and high gyromagnetic ratio. using the schrdinger equation, we discuss the relationship between spin and orbital angular momentum, and the contributions of intrinsic spin and group theory of su(2 ) and so(3 ) in the modeling of mri.
local group dwarf spheroidal galaxies ( dsph ) have some of the largest known m / l ratios for a single galaxy, and an order of magnitude larger than that derived for normal spiral galaxies.   the questions then arise of how do these high m /l ratios arise, are they due to truly high dark matter contents or are there other explanations possible? here   we investigate whether or not the apparent dark matter simply can be in the form of low - mass stellar objects. using the wfpc2 on board hst during 1997, 1998, and 1999, we obtain a deep luminosity function of a dSph with lots of apparent light and compare that to the luminosity functions of a system known to contain no dark matter, such as a globular cluster. from the results   it is shown that the observed velocity dispersion in the central parts of the ds ph is due to a very large spread in metallicity, @xmath4@xmath8 dex, which is in excess of the value expected for purely stellar systems with a standard imf. however, the distribution of this spread is also found to be much smaller than that expected for
the problem of solute transport in porous media is relevant to many environmental, water supply and industrial processes.   the present work uses a transparent square network of ducts of random widths to investigate the influence of mixing and transport processes at the pore scale on dispersion of tracer particles in homogeneous porous media. using dye as a solute, high resolution maps of the relative concentration distribution are obtained through calibrated light absorption measurements while measuring simultaneously the time lag between the invasion of channels parallel and transverse to the mean flow. by combining macroscopic and local scale measurements  , we show that the dispersion coefficient of a tracer can be estimated quantitatively for a pclet number of the order of @xmath11 while the local measurements suggest interpretations in terms of variations of the degree of mixing at the junctions.
the pulsation of   was observed by the narrow field instruments ( nfis ) aboard the italian - dutch x  ray satellite  ( @xcite ) from 1998 september 4 15:41:46 to septmber 5 07:20:35 ut.   the source is a neutron star with a high - energy cutoff that makes its spectra rapidly drop above @xmath04050  kev, which is related to the neutron star magnetic field strength ( ~11  kpc ). in this study   we show that the source has a strong magnetic field, with a value of ~6.5  g / cm2 and a diameter of ~1.8  km. using spectral analysis of the low energy spectrum of the source, we find that the magnetic field of  is about 1.5 times stronger than that of the nearest neutron star, and that the distance to the source can be determined by assuming that the two neutron stars are rotating at their equilibrium period.
we present a protocol for parameter - independent measurements of quantum key distributions using stimulated parametric down - conversion ( pdc ) singlets.   we show that the singlets allow a precision scaling at the heisenberg limit ( for which noise scales as @xmath1 with respect to the light intensity or particle number ). under incoherent photon loss measurement precision is naturally degraded, but at a much gentler rate than other proposals.
the standard model of particle physics is plagued by the problem of triviality in the sector describing quantum electrodynamics ( qed ) and in the higgs sector, which forbids to extend the standard model beyond a certain ultraviolet scale.   the concept of asymptotic safety was introduced by steven weinberg in the context of quantum field theory ( qft ) in the 1990s and has been applied to a number of models ranging from four - fermion models, simple yukawa systems, nonlinear sigma models in @xmath2, extra - dimensional gauge theories, and gravity. in this contribution   we investigate a toy model for thestandard model without gauge fields and with a particular chiral left / right asymmetry @xcite. to leading order in the derivative expansion, we find an asymptonically safe theory which is well - defined on all scales ( renormalisable ) with a highly predictive power and comparatively simple from a computational point of view.
spin squeezing of the oh molecule is a technique of interest at the frontiers of precision measurement.   we consider spin squeezing of a single noninteracting molecule with angular momentum @xmath11 using an effective eight - dimensional matrix hamiltonian that has been shown to model recent oh experiments quite well, and has also been diagonalized analytically. in this article, we demonstrate that for zeeman and stark shifts small compared to the lambda - doublet splitting of the Oh ground state, this hamiltonians can yield spin - squeezing of all the types considered by kitagawa and ueda, law et al., and agarwal and puri ( 2012 ) . here  , we provide analytic and numerical results, discuss the optimization of the field strengths, and include the effects of field misalignment in our treatment.
we describe here a superconducting quantum interference device ( squid magnetometer ) designed to allow high - sensitivity measurements down to @xmath3 mk, while retaining the compatibility with the sample holders used in commercial magnetometers.   the system is based on a leiden cryogenics mnk126 - 400rof dilution refrigerator that allows the sample to be thermalized directly by the flow of condensed@xmath1he from the mixing chamber of the refrigerator to the cold plate of the refrigerator. as a consequence  , the sample can be inserted into the machine without any further manipulation, which constitutes an obvious advantage for the study of metallic nanoclusters, which show spectacular quantum - size effects in their thermodynamic properties at very low temperatures.
the supercosmos recons group ( the research consortium on nearby stars ) is working to identify hidden members of the solar neighborhood within 25 pc to match the horizons of the cns and nstars efforts.   we have focused our efforts on the southern hemisphere because that portion of the sky has been historically underrepresented and is expected to yield rich treasures in the form of new stellar neighbors. in this paper  , we discuss recent photometric distance estimates made using photometry from a combination of optical ccds and infrared arrays, which is an effective intermediate method for refining membership of the sun s solar neighborhood. with the help of complementary spectroscopy, we have also improved the accuracy of photometric distances determined via scanned photographic plates and improved the precision of those determined via ccd photometry.
the hartree - fock - bogoliubov theory ( hfb ) is a powerful tool for the study of neutron - rich nuclei.   it is based on the notion that the mean field and the pairing field are coupled to the particle continuum at @xmath9, and that the weakly bound states near the neutron driplines are weakly bonded to the continuum states giving rise to neutron halos and neutron skins. in this paper   we present a new approach to the hfb calculations of exotic nuclei @xcite, which takes into account the large number of rare isotopes that can be studied with the ria ( rare isotope accelerator ) facility under construction in the u.s.
a vehicle moving through the stratosphere ( altitudes 40km-50 km ) at hypersonic velocities ( 8 - 15 mach ) is covered by a plasma sheath which is opaque to frequencies lower than @xmath3.   direct communication through such a plasma to and from the vehicle is impossible because frequencies suitable for long distance propagation through the atmosphere are usually much less than those used for navigational satellite systems. here   we propose a simple solution to this problem using nonlinear properties of plasma to render it effectively transparent to the signal. in this way  , the vehicle can be used as an antenna to communicate with a receiver on board the other side of the vehicle.
the trans - planckian regime of quantum gravity is the most powerful framework to address quantum gravity problems.   however, the extended nature of ( super ) strings makes them unable to probe this regime : as opposed to hypothetical point - like objects, increasing the energy is not enough to make them shorter and shorter ; as more and more excitation modes are switched - on, the string elongates @xcite bouncing back to a long - distance regime. in a recent paper, dvali and collaborators have proposed a clever way to by - pass this problem, by pointing - out the existence of a " black hole barrier" shielding the trans-planckian regimes to any physical probe. using this method,   they show that the quantum field configuration of a black hole can be seen as either an infra - red field configuration with a radius of radius or a trans -Planckian test - particle with energy. from this point of view  , it is possible to distinguish between the two types of experimental objects, because both are self - gravitating black holes, and the curvature singularity of the black hole is the same as that of the mass of the test - particles.
high resolution shock - capturing ( hrsc ) schemes have become a powerful tool to investigate fluid dynamics in non - linear regimes.   they are particularly useful for time - dependent, explicit computations of highly supersonic flows in the presence of strong discontinuities and it can be employed under different regimes, i.e., classical, relativistic unmagnetized and magnetized flows. here   we present a multi - physics, multi - algorithm high resolution code, pluto, which is designed to integrate a general system of conservation laws with the so - called reconstruct - solve - average ( rsa ) strategy used by most hrsc algorithms. using this approach,   a riemann problem is first reconstructed using piecewise monotonic interpolants inside each computational cell and then solved at each interface with discontinuous left and right states and the solution is finally evolved in time. since this sequence of steps is quite general for many systems of conserved conservation laws, it provides a general framework under which we have developed a multidimensional high resolution simulation code, ppluto. as a result  , the code is structured in a modular way allowing a new module to be easily incorporated.
the optimization of maintenance is a very important problem in the analysis of complex systems.   it determines when maintenance tasks should be performed on the system and these intervention dates should be chosen to optimize a cost function, that is to say, maximize a performance function or, similarly, minimize a loss function. here  , we present a method to compute the optimal cost as well as a quasi optimal stopping rule for a piecewise - deterministic markov process ( pdmp ) model of an aluminum metallic structure subject to corrosion. by means of this method,   we can predict the optimal maintenance date based on the past history of the corrosion process and find the optimal time to perform the maintenance before the corrosion has occurred. moreover, we can estimate the probability of performing the maintenance if the predicted date is below a prescribed threshold.
the wolf - rayet ( wr ) star wr  48a  was discovered in a near - infrared survey and originally classified as a wc9 object @xcite with a current spectral classification of wc8.   it is located inside the g305 star - forming region in the scutum crux arm of the galaxy and its proximity to two compact infrared clusters ( danks 1 and 2 ) suggests that this wr star likely originates from one or the other@xcite.. the x - ray spectra of wr 48a  are very luminous, with the largest known luminosity of @xmath13  ergs s@xmath6 being observed for a wr+wc9 star ( @x Math17  =  6.7  kpc ).    the presence of a high - temperature x - rays component in the emission lines indicates that the star is a colliding - stellar - wind ( csw ) binary system.
the x - ray spectrum of the seyfert galaxies and blazars has been studied with the egret instrument on _ cgro  in the 1990s.   the results have established the presence of @xmath11 relativistic plasma at small angles to the observers line of sight, and the so called " tev" blazar objects ( fsrqs and bl lac objects ) are similar but with a peak power shifted to even greater energies. here   we review the current state of knowledge about the comptonizing plasma of these objects, and discuss the role of the synchrotron self compton model in their contribution to the hard - x -ray band.
the @xmath3 edges high - band receiver is calibrated to a temperature scale that nominally targets the epoch of reionization ( eor ) of the intergalactic medium ( igm ) during cosmic dawn and the cosmic dawn at redshidfts, australia.   the calibration is achieved by converting the noise power measured by the antenna at the receiver input to an absolute antenna temperature scale, properly accounting for impedance mismatches between the receiver and the antenna, removing the effect of antenna losses, and compensating for beam chromaticity. in this paper  , we describe the laboratory calibration of the @x Math3 edges wideband receiver using measurements of the spectra, reflection coefficients, and physical temperatures of four absolute calibrators connected externally to the receiver output.. the results show that the calibration process is highly accurate and reproducible, with precision ranging from 0.1 to 0.5 mhz and accuracy ranging from 1.0 to 2.0% over the entire spectrum of the global sky - average signal. as a result, the calibration can be used to estimate the spectral index of diffuse foregrounds in low - foreground regions of the ionosphere and to quantify the duration of the
weak value amplification ( wva ) techniques have been successfully applied in the lab to measure with high precision the optical spin hall effect and other polarization dependent beam deflections, interferometric deflections of optical beams, phase shifts, phase shift, frequency shifts, temperature shifts, and velocity measurements.   although these experimental findings have been employed in a number of different research groups and applied to metrological questions of a variety of different physical parameters, there are still some open questions and even controversy about how and to what extent wva techniques help against technical noise, or give some kind of technical advantage in comparison to the standard measurement techniques. in this work  , we analyze some of these models and examples using fisher information and maximum likelihood methods in order to understand in precisely what sense they give or fail to give a technical advantage, as well as describe other technical advantages in beam deflection ( and derivative ) experiments where the imaginary wva technique does lead to the optimal fisher information even in the presence of some types of technical noise.
this article is on the one hand on models of weak arithmetics and on the other on proof complexity, i.e. the question of how long formal proofs of tautologies have to be in given proof systems.   we are interested in the strength of the theory obtained by restricting our objects of reasoning to a small initial part of a given model. since a two - sorted theory, such as @xmath3, is much stronger on its number part than on its set part, it is likely that certain cuts of models of  are models of the provably stronger theory@xmath1. here   this is confirmed by a sub exponential simulation of frege by bounded depth frege using a combinatoric argument. in section    we briefly recapture some basics about complexity theory, bounded arithmetic, proof complexity and the various connections between them. in sections   ( 1 ) and ( 2 ) we prove a formalization of nepomnjascij s theorem in the polylogarithmic cut of a model of @x math0. using a standard algorithm for evaluating circuits and then applying the formalized version of nepomasjascij
the compact steep spectrum ( css ) source 3c138 is a powerful quasar with a convex spectrum peaked at @xmath1130 mhz with a steep high frequency spectrum of 0.65.   it has a second - scale radio structure that consists of a core, several bright jet knots, a compact lobe to the east and a fainter, more diffuse lobe to its western end. in this paper, we present the results on the core identification using the spectral data obtained from the first quasi - simultaneous multi - frequency vlbi imaging of 3c 138.    the observations were performed with the nrao very long baseline array ( vlba ) on august 20, 2001. with the capability of the frequency switching, 3c 137 was observed at four frequency bands including the dual frequency ( 2.3/8.4 ghz ), 5.0 ghz and 15.4 Ghz. for each scan, data were recorded in 1 bit sampling vlBA format with a total bandwidth of 64 mhz ( eight 8 mhz channels per circular polarization at each station ) per circular polarized polarization at both five.0 and 15% linear polarization. as a result,
the relativistic hydrodynamics of a hot charge - symmetric electron - positron - photon ( @xmath3 ) plasma droplet in the order of the electron mass is studied.   the expansion dynamics of the droplet is quantified by means of the equations of motion of local energy and momentum conservation expressed as the equation of state, with the thermodynamic pressure as the covariant derivative. for an isotropic medium ( gas or fluid or plasma ), the temperature profile and velocity profile of the plasma droplets   are considered using the planar geometry of the relativistically conserved model. to estimate the spectrum of emitted photons, the thermalization and the collective excitation modes are taken into account within the context of the spacetime of the observed expansion dynamics. from the results   it can be concluded that the emission of photons from a @x Math3 plasma is due to the formation of a spherically symmetric expansion of the liquid droplet at initial temperatures much larger than its electron mass.. the time evolution of the temperature profiles and the velocity profiles is well described by means on the basis of the calculations of the trajectories of the experimental data.
damped lyman-@xmath2 absorption systems ( dlas ) are important probes of the early - to - present day universe as they account for at least 80% of the neutral gas mass density in the universe.   we report the first detection of a redshifted dla towards 1622 + 238 ( 3c336 ) by the westerbork synthesis radio telescope ( wsrt ), which occults radio - loud quasars with a band - width of 5 mhz over 2048 channels ( dual polarisation ) and a frequency range of 857.68 mhz to 856.6 mhz. using the miriad interferometry reduction package, we extracted a summed spectrum from the emission region of the continuum map and found absorption towards the peak of the radio continuum apparent in both polarisations. upon subtracting the continuum with a first order polynomial from the line free channels of the combined polarisations,   a single gaussian gives the fit shown here : the line is present in the centre and surrounding pixels, but disappears with increasing proximity from the centre pixel. on the other hand, there is no overall ripple in the spectrum due to the loss of time - dependent
mass spectrometry - based proteomics is a rapidly advancing field, but, as an emerging field, it still requires reliable tools for the storage, exchange and analysis of experimental data.   liquid chromatography - ms ( lc - ms ) technologies have become available which can generate a huge quantity of data potentially able to address relevant questions, e.g., to identify proteins in a biological sample, to quantify their concentration, to monitor post - translational modifications, to measure individual protein turnover, to infer on interactions with other proteins, transcripts, drugs or molecules. however, the data hostage held by different instrument proprietary formats slows down the evolution of proteomics, mainly because comparisons among different experiments, or analytical methods, often become unfeasible. therefore, a major challenge facing proteomic research is how to manage the overwhelming amount of data in order to extract the desired information. here  , we present a new data format for handling high - throughput quantitative proteomics data, called mzml_@xcite, which combines the best features of both the human proteome organization ( hupo ) and the @xcite standards initiative ( psi ) data formats, namely the minimum information about a proteomics experiment
deep learning approaches have proven successful in various applications, from machine vision to language processing.   however, it is perhaps less clear whether current deep networks truly support neuronal representations and processes that naturally allow for flexible, rich reasoning about e.g.  objects and their relations in visual scenes, and what machinery is necessary to learn such representations from data in a mostly unsupervised way. at the implementational level  , there is a host of cortical computations not captured by the simplified mechanisms utilized in deep networks, from the complex laminar organization of the cortex to dendritic computations or neuronal spikes and their timing. here, we aim to demonstrate the potential functional role of neuronal synchrony in a framework that is amenable to deep learning, using a mathematical idealization that naturally extends current deep neural networks while still being interpretable in the context of biological models. within this framework, we use complex - valued units, such that each neuron s output is described by both a firing rate and a phase variable, and phase variables across neurons represent relative timing of activity. with this approach, we show that synchrony is a key element of neuronal information processing, and that it can be used to bind neuronal subpopulations
the existence of persistent currents in metallic rings was predicted by hund in 1938 @xcite.   more than 30 years later bloch and kulik confirmed this prediction by means of quantum  mechanical models. here  , we propose several possible mechanisms for controlling the response of the metallic mesoscopic rings and determine the conditions for which the transition from paramagnetic to diamagnetic current is able to occur. at low temperature, small normal metal rings threaded by a magnetic flux can display persistent and non - dissipative currents carried by phase - coherent electrons. under right circumstances electrons in the ring   are able to preserve its coherence which in turn results in the persistent ( dissipationless ) current induced by the static applied magnetic field.
the seminal paper  @xcite introduced an important class of sequential optimization problems, otherwise known as multi - armed bandits, where the objective is to devise a sampling policy that maximizes expected cumulative rewards over a finite time horizon.   the first work to venture outside the realm of parametric modeling assumptions appeared in @xcite, where near - optimal bounds on the regret for a variant of the @xmath3-greedy policy were proved in the case of a two - armed bandit problem under only two assumptions on the underlying functional form that governs the statistical populations responses. in the present paper, we extend this formulation to the #xmath4-armed bandid problem with covariates when the mean response in each arm may be large. using a customized definition of the margin parameter  , we prove new regret bounds for binned successive elimination ( bse ) that improve upon the canonical limits proved in  @xaite and  @xficite. by virtue of the presence of covariates,   these new bounds are not limited to the range of values of the initial margin parameter, but also to the entire range of the variance value of the covariate, which is often used in the context
we have calculated the momentum shift of high transverse momentum ( ) hadrons in au+au and p+p collisions from the rhic year-7 and year-10 runs of the phenix experiment.   we have statistically extracted the fractional momentum loss of the partons using the hadron spectra measured in @xmath1 and@xmath6 s in 0 - 10% au+u collisions at = 39, 62 and 200gev from the same dataset. for the corresponding dataset, we found that the changes by a factor of three from 39 to 200gevs are due to the suppression of the yields of high single hadrons which are leading hadrons of jets.
rich clusters of galaxies are among the largest gravitationally bound structures in the universe.   they are also notable for their high fraction ( typically @xmath7% ) of member galaxies of early - type morphology, as compared to galaxy groups or the field. within the framework of large - scale structure theory,   rich clusters arise from the largest fluctuations in the initial random field of density perturbations, and their demographics are sensitive diagnostics of the cosmological world model and the origin of structure. from this perspective  , it is useful to take an inventory of clusters, and compare with the universe as a whole. since rich clusters do represent regions of largest initial overdensity, star formation may initiate at higher redshift, proceed with enhanced efficiency, or be characterized by an initial mass function skewed toward higher mass stars when compared to more typical regions. if so, there is an opportunity to search for possible variations in star formation with epoch or environment, given a suitable class of objects for comparison. here   we discuss the intergalactic medium in _ groups _ of galaxies, which generally include hundreds ( or even thousands ) of galaxies within a region spanning several mpc, and have electron temperatures ranging from 20 to
we describe in this paper analysis procedures that can answer two of the most important questions of neutrino research.   how can one determine the total solar neutrine fluxes ( @xmath12, and@xmath10 ) for comparison with solar model predictions?   what is the contribution of sterile neutrinos to these fluxes? using a combination of the charged current ( cc ) and the charged plus neutral - current measurement with super - kamiokande experiments, we show that the results of the sudbury neutrini observatory ( sno ) experiment provide an independent determination of the flux of active @x Math0b neutrines independent of the solar model. by contrast, the measurement of the neutral current ( nc ) rate by the sno experiment yields results that depend more on the sterile mix but which can nevertheless be relatively accurate at about the @x maths13 confidence level. from these results, we conclude that new physics is required to resolve the long - standing problem of the origin of the discrepancies between the predictions of the standard solar model and the observed solar neut raman rates.
prominences ( filaments ) in many solar events erupt and draw away from the sun as parts of coronal mass ejections ( cmes ).   eruptive events associated with flares produce various phenomena of different temporal and spatial scales, including absorption phenomena in the he  ii 304    line and transient depressions of soft x - ray and extreme ultraviolet emissions in the h@xmath3 line. here   we review the spectrum of these phenomena and discuss the possible causes of them.
spin - splitting changes in asymmetric coupled double quantum wells ( acqw ), caused by abrupt interfaces, when an in - plane magnetic field is applied to @xmath3-based heterostructures are studied.   the model is based on an extended version of the@xmath1 kane formalism with nonsymmetric boundary conditions to calculate the band structure and dispersion laws for the two - dimensional ( 2d ) spin - orbit interaction between the excited and non - excited states of the dual quantum wells. as a result  , we find that the effective hamiltonian of the quenched state is reduced from a pauli contribution to a linear one after the squared momentum substitution by its quantized value due to confinement. also, the land factor is affected by the applied magnetic field, but this dependence is negligible for in - Plane magnetic fields and low electron density.
we have obtained deep - field photometry of six isolated dwarf galaxies in the local group : ic  1613, leo  a, cetus, tucana, and phoenix.   we show that the star formation histories ( sfhs ) of these galaxies are nearly constant at all times, and that the age - metallicity relations ( amrs ) of the galaxies are very similar to those of the larger spiral galaxies.. this is consistent with the results of the recent work by @xcite, who showed that most irregular galaxies were consistent with nearly constant star formation over their lifetimes.
we investigate the spin - orbital model on the square lattice, away from the @xmath13 point and to identify all the quantum transitions.   we also investigate the model in the limit of strong quartic interaction ( @x Math16 ). using both spin - wave and perturbation methods we find that the hamiltonian (  ) describes two almost independent heisenberg subsystems with two sublattices in each subsystem. for the nel - ordered spin subsystem the ground state is a direct product of the spherically symmetric spin and isospin operators at the lattice site@xmath12, and this ground state has spontaneous breaking of the translational lattice symmetry. by taking into account the strong coulomb repulsion of the transition metal @x math2- electrons we show that the quasiexpermeable orbitals are anisotropic plaquette liquid in the vicinity of the @Xmath0 point.
the fermilab tevatron collider is currently between data runs.   the period from 1992 - 1996, known as run  1, saw both the cdf and d  experiments accumulate approximately @xmath5 of integrated luminosity. in this talk  , i will discuss some of the methods and considerations for these measurements.. the goal here is not to comprehensively present the results, but to discuss how the results are obtained and what the important elements are in these measurements : the sample of events, the proper decay time and the measured flavor for each event.
in this paper we study a diffusion - limited coalescence process in one dimension : @xmath0, which yields itself to _ exact  analysis.   we show that a solution is possible even in the presence of background drift, and in the absence of a trap. when in the long - time asymptotic limit the stationary state of the system is a nonequilibrium state, the distance between a given particle and the nearest particle to its right ( the  forward " inter - particle distribution function  ) is exactly the same as in equilibrium, even under the influence of a trapped particle. by comparing our results to the exact solution of the method of empty intervals ( ipdf ), we explore in what ways the reaction - diffusion equation is approximate, and find out the optimal rate constants of the corresponding reaction - diffusivity equation.
massive galaxies are on average more compact in the primitive universe.   if the mechanism which is growing in size these galaxies is stochastic ( such as mergers ), there should exist relic galaxies ( that is, survivors to this size growth ). in our recent article @xcite, we address the question about which is the best environment for looking for massive relic galaxies. using simulations and observations, we find that the fraction of old superdense galaxies is higher in clusters than in normal - sized galaxies.
we investigate the anisotropic effect in the quantum hall ( qh ) systems by means of the matrix - model language.   this can be done by extending susskind   polychronakos s ( sp ) idea to coupled harmonic oscillators. making use of a unitary transformation  , we end up with a diagonalized system that allows us to define creation and annihilation matrix operators. calculating the area of the qh droplet of matrix variables,   we obtain a filling factor @xmath7, which depends on an anisotropy parameter @x Math8, thus generalizing the isotropic ( poly chronakos ) factor@xmath9.    we build up the ground state of our model as well as its excitations in terms of two different representations, those corresponding to variables before and after a suitable transformation. under some conditions   our ground state can be visualized similarly to the laughlin liquid.
vibro - impacting systems are often used to measure surface topography and chemical properties of samples on the nanoscale by gently hitting them with a vibrating cantilever.   it is important to understand the complex impacting dynamics of these systems so that the inverse problem of describing the sample can be performed effectively. in this paper  , we study grazing bifurcations of the three - dimensional piecewise - smooth ode system using a low degree - of - freedom oscillatory deceleration energy transfer ( ode ) model. as parameters vary, the system may transition from an impact - free regime to the repeated ( though not necessarily regular ) occurrence of impacts. in phase space,   the transition occurs when the periodic orbit of the ode model attains an intersection with @xmath4, which corresponds to locations or instances where mechanical components come into contact, or lose contact. here   we show that the evolution of the system between impacts is tracked in phases by tracking the periodic behaviour of the Ode model in relation to the timing of the impacts. for each impact, we find that the frequency of impacts is proportional to the number of times the system is in contact with the material
the one - player combinatorial game flood - it, introduced by arthur, clifford, jalsenius, montanaro and sach in @xcite, is known to be computationally difficult when played on a planar graph.   we show that the problem of determining the minimum number of moves required to flood the entire graph with all vertices in the same monochromatic component is solvable in polynomial time on any coloured graph, if we are allowed to make moves anywhere in the graph, and that this result also holds for the " fixed " version of the game, where all moves must be played at the same fixed vertex ( usually the vertex corresponding to the top left square when the board is an @xmath1 grid ). however, the problem is np - hard when restricted to trees, or when the number of colours is limited to some fixed set of size @x Math4.    we find that the hardness of the free - flood - It problem can be extended to the fixed variant, where only colours from some fixed colour - set @x math4 are used, and demonstrate that this problem is NP - hard on any graph with a fixed number of
quantum information and quantum technology require the readout of classical data by means of quantum states.   the latter can overcome the classical reading capacity, obtained by probing with classical light, in several relevant settings. here   we show that the quantum reading capacity of a quantum optical memory can be increased by using local phase shift keying to read out the encoded information from the transmitted signal at the same energy as the quantum state of the transmitters. for a particular type of memory device,   this is possible through the use of effective quantum channels, which are assumed to be quantum channels corresponding to local phase shifts.
dark halos are usually thought to stabilize galactic disks against non - axisymmetric instabilities.   recent numerical simulations have shown that quite the reverse might be true. in this paper   i show how the shearing sheet model of a thin, differentially rotating stellar disk can be used to investigate the effects of a live dark halo on the self  gravity of the disk and the formation of wakes in the region of interest where the disk is embedded in the halo. by simulating the dynamics of a patch of a galactic disk immersed in a live black halo  , i show that the density of the inner reflector increases with increasing distance from the galactic center and that the lifetime of the wakes is longer in the regions of interest when the disk has been embedded in a dark h Halo than in the unperturbed region.. these results support the hypothesis that the presence of a darkhalo reduces the destabilizing self  gravitation of the disks.
near - infrared transmission spectroscopy observations for the extreme gas giant wasp-121b @xcite are presented.   the planet is in a 1.3 day polar orbit around an f6v host star, with a semimajor axis of 0.025au, and is one of the most inflated exoplanets known, with mass @xmath11 and radius@xmath12. to test the hypothesis that gaseous titanium oxide ( tio ) and vanadium oxide ( vo ) are abundant in the upper atmosphere of an irradiated gas giant, we measured the temperature of the atmosphere using the _ hubble space telescope_ ( _ hst _ ) wide field camera 3 ( wfc3 ) during a single transiting transit of wasp/121b on 2016 february 6 ut using the grism g141 and forward scanning spectroscopic mode. at temperatures above @x Math10k,   tio / vo absorption is prominent in transmission spectra, which is consistent with a thermal inversion, as incoming stellar radiation is absorbed at low pressures. here  , we show that this is not the case, as the observed temperature is close to the equilibrium temperature of
the lower - truncated coherent states ( ltcs ) are a class of nonclassical states which are generated from superpositions of two coherent states.   they are orthogonal to each other and have been experimentally realized by photon - addition and state truncation. in this work,   the properties of these states are presented and compared with those of the upper- and truncated coherence states. also, the relation between the ltc and the photon - added coherent states(pacs ) is established. finally, the sub - poissonian statistics of the pacs are discussed.
the stopping power of a charged particle as it traverses dense matter is a fundamental probe of the matter properties.   accurate theoretical calculations and experimental measurements of this quantity became one of the great early successes of the classical and quantum theories of electromagnetic interactions  @xcite. in the last decade,   advances in high energy many - body quantum chromodynamics ( qcd ) have enabled exploration of parton energy loss in a novel hot and dense state of nuclear matter - the quark - gluon plasma ( qgp ). here   we show that both coherent and inelastic scattering on the nucleus have comparable impact on the observed cross section attenuation in this kinematic range. using a perturbative qcd calculation that includes the cronin effect, high - twist shadowing, and initial - state energy loss  , we find that the suppression of energetic particle production in nucleus - nucleus ( a+a ) collisions, dubbed jet quenching, is dominated by bremsstrahlung processes in the limit of large energies. at low forward rapidity, however, the effect of coherent scattering is more pronounced than that of final - state inelastic scattering. with respect to the
gasoline is a parallel @xmath0-body and gasdynamics code for numerical simulations of self - gravitating systems.   it is based on the pkdgrav parallel@xmath1-body tree code designed by @xcite and has been used to simulate a range of complex astrophysical systems including star formation, inelastic collisions, solar system dynamics, stability of disks, stellar dynamics and quasi - linear aspects of the growth of large scale structure in the universe. with the advent of digital computers, improvements in storage and processing power   have dramatically increased the scale of achievable simulations. increasing problem sizes have forced simulators to pursue more complex algorithms and adaptivity in space and time. in this context   we describe the development of gasoline, a parallel algorithm for calculating gravitational forces and smoothed particle hydrodynamics ( sph ) in the context of computational astrophysics. using a hierarchical timestepping scheme, we examine the performance of gasoline when applied to challenging numerical simulations from the perspective of time - adaptivity and performance in areas such as galaxy and planet formation. at the same time  , we discuss the current and potential benefits of multiple timesteps for time adaptivity
relativistic heavy ion collision experiments at the bnl - ags ( au(10.7  agev)+au ) and at the cern - sps ( pb(160  ageV)+pb ) have yielded a large variety of fascinating data.   however, there is no unique theoretical description of the underlying hadron@xmath3hadron interactions, with their vastly different characteristics at different incident energies and in different kinematic intervals. here   we present and analyze the detailed elementary h - h input used in the transport model urqmd, which is the first microscopic model which attempts to include the color coherent phenomena. using the additive quark model ( aqm ), we calculate unknown cross - sections for the ten most frequent hadronic- and nuclear - type collisions at the full   sps energy namely, @xmath7 ( in decreasing order of frequency ) and @x math2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 18 + 19 + 20 + 21 + 20   gev per nucleon at lhc. by comparing the results with the
the telescope array ( ta ) is the largest detector of ultra - high energy cosmic rays in the northern hemisphere.   it consists of 38 fluorescence detectors ( fds ) and an array of 507 surface detectors ( sds ), which measure longitudinal development and primary energies of air showers in the atmosphere from the amounts of light emitted by atmospheric molecules excited by charged particles in the showers @xcite. to determine the arrival direction and primary energy of an air shower in sd  , we have developed a hybrid reconstruction method using the timing information of an sd at which air shower particles hit the ground as well as the lateral distribution of local particle densities around the shower core. with this method,   the time differences between signals of the photo - tube pixels with small angular separations are used to calculate the relative timing differences of particle arrivals between sds, and the lateral distributions of local density of the shower particles at the ground. here, we show that the inclusion of sd timing in fd monocular reconstruction significantly improves the accuracy in the determination of shower geometry ( a similar method has been used in the hires - mia @xcite and the pierre auger observatory    )
the energy transfer mechanism of excitation energy transfer in multichromophoric arrays of photosynthetic complexes can often be described by a semiclassical frster theory which involves incoherent hopping of the excitations between energy levels forster65,scholes03,maybook.   we develop a quantum walk approach, based on a quantum trajectory picture in the born - markov and secular approximations, as a natural framework for incorporating quantum dynamical effects in energy transfer, as opposed to a classical random walk picture that can effectively describe the excitation hopping in the frster model.. the quantum walks are of particular interest as potential computational tools @xcite, and applications to quantum cellular automata, quantum optical systems, and coherent excitation transport.
the hadronic contributions to the rare decays @xmath1 and @xcite are well described in the literature.   the charm loops are subdominant numerically in the kinematical regions of interest, but the related uncertainty needs to be properly estimated in order to obtain accurate predictions. in the present paper   we formulate the operator product expansion ( ope ) for the high-@xmath2 region of @x Math1 from the outset.    we also discuss the issue of quark - hadron duality, which appears relevant because of the existence of a very narrow @x maths13 resonance structure in the @x math2 region.
in hierarchical galaxy formation models, stars are formed in condensations of cooled baryons within dark matter halos.   the response of dark matter to baryonic infall has traditionally been calculated using the model of adiabatic contraction ( ac ). here   we analyze high - resolution cosmological simulations of eight cluster - sized and one galaxy - sized systems in a concordance @xmath6cdm model. for each halo, we analyze two sets of simulations which start from the same initial conditions but include different physical processes : the first set of simulations follows the dynamics of gas's dynamics without radiative cooling ; the second set includes gas cooling and heating, and star formation. in both regimes  , the ac model works surprisingly well. however, many of the assumptions of the standard ac model are not valid. for example, the orbits of particles in realistic dark matter Halos are highly eccentric. for such orbits the combination@xmath0, which forms the basis of the current ac model, varies with the orbital phase and is not adi abatically invariant. a better version of ac model can be constructed by taking into account eccentricities of particle orbits.
double bars are systems where a small, faster - rotating " inner" bar forms concentrically within a large, " outer" bar.   they have been proposed as a mechanism for efficiently feeding gas into the centers of galaxies and fuelling activity there. here  , we discuss some results from a survey designed to find out just how common inner bars  and other structures inside bars  might be, and learn something of their characteristics. using ellipse fits to isophotes, unsharp masking, and color maps, we identify and measure a variety of central structures in these barred galaxies : inner bars, inner disks, nuclear rings, nuclear spirals, and near - nuclear off - plane dust. among these structures,   inner bars are surprisingly common : they occur in at least one - quarter ( possibly as many as 40% ) of the barred s0sa galaxies in the wiyn sample, with no discernible dependence on hubble type or outer - bar strength. however, one galaxy is actually triple - barred ( ngc  2681 ; see erwin & sparke 1999 ).
the @xmath4 expansion of the transition rates for the decays of heavy flavoured hadrons is a well - known method for the determination of the ckm sektor of the standard model.   the purpose of this talk is to give a short review of the developments in the field of inclusive decays using the same approach as for exclusive decays, which are formulated in the laguage of effective field theory, the so called heavy quark effective theory ( hqet ). by systematically accessing the mass dependence of any matrix element involving heavy hadron states andheavy quark fields   one can systematically extract the decay probability of the decay products in terms of a @x Math4 expansion, which is obtained by an approach similar to the one known from deep inelastic scattering. in the case of inclusive semileptonic decays the method is applied to the charged lepton energy spectrum in which the endpoint region can not be described by the @x math4 expansion.    it turns out that the endpoint regions can not been described by a @ xmath4 extension ; rather a partial resummation of the @Xmath4 expand is required, which resembles the leading twist term in deep
the consensus problem, in which we ask whether the unanimousity of one among different competing states ( e.g., opinions ) is reached, is of interest in various disciplines including political science, sociology, and statistical physics.   the consensus problem is usually assumed that each individual possesses one of the different states that can flip over time. here  , we extend the abrams and strogatz ( as ) model to the case of competition among a general number of languages.    we show that the behavior of the as model is essentially different between the two versions of the model, i.e., the coexistence of different states and the consensus equilibria are both stable only when there are more than two competing states.
monochromatic interferometric observations of the centre - to - limb variations ( clvs ) of @xmath0 cet and r leo have been used to investigate the geometrical and physical structure of the mira atmospheres and to test the quality of mira models.   the results of these observations have been compared with those of high - precision measurements of m - type mira diameters obtained at kitt peak national observatory with the lunar - occultation technique, which show that the size of the photobleaching layers is not affected by the shape of the clv of the star s intensity but rather by the wavelength - dependence of the observed clv shape. in this contribution  , we discuss the main problems of defining and measuring monochromate radii for mira variables and the concepts of determining " the radius" of a mira variable to be adopted.. we also discuss the use of monochroma interferometry as a tool for analyzing the geomorphological and physical structures of the michelson - labeled mira atmosphere and for scrutinizing modelling assumptions.,conclusionsthe results of this contribution are discussed in terms of the usefulness of
photoacoustic spectroscopy ( pas ) is a very promising method for environmental, industrial, and biological monitoring, due to its ease of use, compactness and its capability of allowing trace gas measurements at the sub - parts per billion ( ppb ) level @xcite.   quartz tuning forks ( qtfs ) have shown great potential as sound transducers for pas and have been increasingly applied to selective and sensitive detection of trace gases since its introduction in 2002. here   we report on a novel qepas sensor design with two micro - resonator ( mr ) tubes, an on - axis mr tube acting as absorption cell and an off - axis Mr tube acoustically coupled, where a 20 khz qtf is placed between or beside the mr tubes to probe the acoustic signal excited in the gas@xcite. the proposed design is based on finite element simulations using a nanosecond pulsed single - mode microparticle optical coherence tomography ( mir ) optical source ( opo ). from the simulations we find that the optimal positions of the qtf in the off - axes are determined by the distance between the gas inlet / outlet tubes and the coupling to
the search for a non - vanishing neutrino rest mass is a key issue in the field of nuclear physics.   the most sensitive process to probe this is double beta decay, which can be seen as two simultaneous neutron decays. here   we review the experimental signatures of these decay modes and discuss the implications of the results.
the star formation history ( sfh ) of a galaxy is fundamental to understand the galaxy evolution process.   the color - magnitude diagram ( cmd ) is the best tool to study and derive theStar formation history of resolved galaxies, but it is only recently that we have properly been able to speak about quantitative determinations of complex star formation histories. in this paper   we present an algorithm for the derivation of the s fh from the comparison of observed and synthetic cmds based on the initial mass function ( imf ), star formation rate, metallicity law and binariety. by using a stellar evolution library,   stars with age and metalicity following a continuous distribution are computed through interpolation in a stellar evolve library, providing synthetic cmd's with smooth, realistic stellar distributions.. the algorithm is intended to be as general as possible and allows a variety of inputs for the initial masses function, starformation rate, meetallicity laws and binarethic properties such as size, density, number of stars, radial velocity, brightness, distance between two stars, and the ratio of young to old stars.    the results obtained show that the method is accurate and robust enough to
a recent work by starobinsky @xcite proposes a new paradigm for the origin of the acceleration of the universe in the presence of a cosmological constant.   the proposed model is based on a minimally coupled scalar field whose energy density would mimic an effective cosmologic constant, which is accelerating the universe expansion at a much lower energy scale than the inflationary phase itself. here  , we discuss the properties of the potential and its possible fine tuning as a function of the Cosmological Constant term.
the jila multidimensional optical nonlinear spectrometer ( jila - monstr ) is a platform for optical multid dimensional fourier - transform spectroscopy.   it is based on a three - pulse excitation scheme that provides four identical laser pulses in a non - collinear box geometry, and uses the fourth pulse as a phase - stabile reference pulse to track the phase with respect to the time delays between excitation pulses. by tracking the phase of the pulses,   the spectra can be transformed into a multid dimensionality spectrum with a fourier transform. using this platform, we demonstrate the use of two - dimensional ( 2d ) 2dft projections to study the effects of phase cycling on the signal collection path. also presented is a straight forward implementation of phase cycle to reduce noise from scattered pump light.
bg geminorum is a rare eclipsing binary system with an unseen primary star and a lobe - filling k supergiant secondary star.   we have acquired high - resolution optical spectra of the star using a high throughput, slit spectrograph mounted at the fred l. whipple observatory 1.5-m telescope on mount hopkins, arizona. to analyze the spectra, we measured continuum magnitudes and indices of strong absorption and emission lines using narrow passbands and calculated the central wavelength for each spectrum. in total, we obtained spectra covering 38007500   at a resolution of @xmath0 6  from bg gem over a period of ~1.5  years ( range 0.8 - 2.2  years ). 	 the spectroscopic observations show that the star is a late g or early k star with a red continuum and strong absorption from the g band, mg  i, na  i, and ba  i blend at @x Math106495.    the spectrum also shows a weak blue continuum and weak he  i emission at 5876   and 6678  , with strong h  i bal
short gamma - ray bursts ( sgrbs ) are the most attractive scenario to explain the phenomenology associated with them, although many alternatives exist.   the recent observations of x - ray afterglows of a large subclass of short gamma - rays have revealed phases of roughly constant luminosity in the x -ray afterglow of a number of these bursts, which are referred to as " x - Ray plateaus " ( _ e.g., @xmath0 ) and last @x Math0.    the x-ray emission is normally associated with an ultra - relativistic jet launched by the black hole ( bh ), produced by the collapse of the binary - merger product ( bmp ), which is a supramassive neutron star ( ns ) that eventually collapses to produce a rapidly rotating bh surrounded by an accreting torus. here  , we present a new model for the formation of the bh and the generation of the sustained gamma- and x -Ray emission from short gamma waves that is based on the presence of a long - lived " central engine " in terms of a protomagnetar, that is, a uniformly rotating object formed in
jupiter is the most luminous planet in the solar system at x - ray wavelength @xcite.   it emits x - rays from magnetic poles by the charge exchange interaction with the solar wind and magnetospheric heavy ions and also by the bremsstrahlung emission via energetic electrons, but there has been no report on such an emission because past instruments lacked the necessary sensitivity to detect the extended hard x-ray emission.    we performed a decisive analysis using a deep 160 ks observation data of jupiter with the _   _ suzaku _ x - Ray imaging spectrometer ( xis )@xcite that observed jupiter on 2006 february 24 - 28 with the x -Ray imaging spectroscopy ( xes ) instrument onboard the Suzaku space telescope. during the observations,   the spacecraft was repointed four times to allow for the planet s motion ( 0.7@xmath61.8 arcmin per day ) and the data reduction was performed on the version 2.0.6.3 screened data provided by the suzakusaku processing facility, using the heasoft analysis package ver 6.3.1.1.
the great annihilator ( ga ) is a binary system with a stellar - mass black hole.   it is the brightest galactic center ( gc ) source at above 20  kev, and was discovered by the einstein observatory @xcite in the direction of the gc region. to investigate the accretion mechanisms of the ga, we performed the suzaku observation on the ga with its high - quality spectrum and low background. using the x - ray spectrum of 1e  1740.7@xmath02942 as a reference, we find that the ga is a supermassive black hole with a temperature of 6.7  kpc, and the magnetic field is strong enough to form a dense molecular cloud ( mc ) near the ga. however, there is no evidence for dense gas accretion from the mc around the ga due to the bondi - hoyle accretion mechanism or a binary companion star.
the optical transient ( ot ) associated with the gamma - ray burst ( grb ) 010222, one of the brightest bursts detected so far, was observed for @xmath18 days both from the indian astronomical observatory ( iao ) and the vainu bappu Observatory ( vbo ) in hanle, ladakh, india.   the ot was observed in the @x Math1 band on feb 22 and 23 using the 1-m zeiss telescope equipped with a ccd imager similar to that in use at iao which is equipped with johnson - cousins@xmath19 filters and a @x maths20 site chip covering a field of @x math22  arcmin at the f/9 cassegrain focus. during the observation period, the ot showed several absorption line systems superimposed on a power - law continuum consisting of red - shifted doublets of fe  ii, mg  ii and a host of other lines which indicate basically three intervening absorbers located at @xMath11 0.927, 1.155 and 1.475. these absorption lines are generally interpreted as indicating that the grb occurred in a galaxy at the highest redshift
the probability distribution of the electron - positron pairs produced in a uniform static electric field is constructed.   the probability distribution is calculated on the basis of the probability - generating function ( pgf ), and the continuum limit approximation is restricted by weak electric fields. in strong electric fields, however, the analytic properties of the pgf are violated and the cumulative probability is divergent. to overcome this problem, we show that the summation over discrete modes restores both the analyticity of thepgf and the convergence of the series. as shown with numerical examples, the main features of the asymptotic behavior of the probabilities are illustrated.
abstractthree - dimensional and time - dependent hydrodynamic simulations are now established as realistic descriptions of the convective photospheres of various classes of stars, and must be applied in any more precise determinations of chemical abundances, oscillation properties, or atmospheric structure.   such models can now be produced for stars with widely different properties, ranging from white dwarfs to red supergiants, and with all sorts of metallicities. using the output from such simulations as temporally and spatially varying model atmospheres, synthetic spectral line profiles can be computed as temporal and spatial averages over the simulation sequence co@xmath4bold models @xcite. these profiles can then be used to reconstruct spectra of exoplanet transits, which reveal details of the atmospheric structure and dynamics of the star s surface. during transit,   an exoplanets hides successive segments of the stellar disk and differential spectroscopy between epochs outside transit, and those during different transit phases, provide Spectra of those particular surface segments that were then hidden behind the planet. if the planet would happen to cross a starspot, even spatially resolved spectra ( with their magnetic signatures ) of such stellar surface features could become attain
the galactic center ( gc ) lies between two giant, energetic lobes associated with outflowing gas.   it has become clear that the gc is driven by a biconical nuclear outflow from the front and back sides of the fermi bubbles ( fbs ), where the x - ray, microwave, and radio emission is strongest. in this letter   we present new uv and radio spectra of the galactic center region to explore the properties of gas entrained in the galactic nuclear out flow. using the hubble space telescope, we have imaged the entire gc region with uv spectroscopy for the first time, including the 21 cm high - velocity clouds ( hvcs ) in the northern fb @xmath0200kms@xmath4, which are thought to be driven by an outflow originating from the central gc.. the uv absorption - line spectra reveal a complex multi - component structure of gas in the gC region, including several stellar directions and two agn directions. among these directions,   the most prominent is the ~21 cm hvc, which is believed to be part of a large - scale nuclear out
weyl semimetals are a new class of materials with pseudo - relativistic quasiparticle excitations.   the electronic excitations are described by an analog of the weyl equation of particle physics, which describes eight two - component chiral spinors @xmath10 ( two for each of the four weyl points ). in this article   we review the history of the use of the ultrarelativistic " massless " dispersion relation to describe three - dimensional ( 3d ) electron excitations in these materials.
the sloan digital sky survey ( sdss ; @xcite ) measures the distribution of galaxies in the nearby universe and the nasa microwave anisotropy probe ( map ; @xmathite ) primarily probes the density distribution of matter and radiation at z=1300.   we use the cross - correlation formalism to find low - redshift tracers that optimize the signal - to - noise from the cross-correlation between the final conditions measured by sdss and the initial conditions probed by map.    we find that sdss quasars with magnitude @x Math3 and galaxies with magnitude@xmath4, which will have photometrically - determined redshifts, are good tracers. using a combination of the sunyaev - zeldovich effect and the sz effect, we show that these tracers give good constraints on the pressure fluctuations in supercluster - scale gas and the equation of state.
we have studied the effect of the side - attachment of quantum dots ( qds ) on the energy spectrum and transport properties of a model quasiperiodic nanostructure, in which atomic sites are side - grafted to every atomic site of a golden mean fibonacci chain.   the results show that the entire energy spectrum of the infinite system turns out to have absolutely continuous subbands of energy. under certain special conditions the existence of these subbands is triggered by a certain special relationship between the off - diagonal elements of the hamiltonian and the electronic eigenstates of the system. this is something that is not expected in any conventional localization scheme, such as the anderson localization, where the single particle states get localized in a disordered array of potentials irrespective of the numerical values of the parameters of the Hamiltonian.
the effect of a magnetic field on an s=1/2 antiferromagnetic chain has been extensively investigated theoretically over many years.   the first detailed experimental study of such systems at large fields with @xmath5 of@xmath6 was only performed very recently,@xcite on cu benzoate. while these experiments verified, in detail, the expected field - dependent shift of the wave - vector at which a gap minimum occurs, they also discovered an unexpected result : a non - zero gap appeared which seemed to scale as approximately @x Math9, with strong dependence on the field orientation.    this gap might arise from the staggered @x math10 ( gyromagnetic)-tensor, associated with the low symmetry of the crystal structure and the presence of 2 crystallographically inequivalent cu sites on each chain.. the purpose of this paper is to provide more details and some extensions of the results in . 	 we determine the scaling of gap with field, order parameter with field and susceptibility with temperature using the bethe ansatz equations. by means of logarithmic corrections including a marginally irrelevant operator, we show that the gap scales with field for both uniform and staggered fields
the efimov effect is a phenomenon occurring in a three - particle system of identical bosons, in which there is an accumulation of bound states near the point of zero energy and diverging scattering length of the interparticle interaction.   it was first observed in cesium by studying three - body recombination in a gas of ultracold atoms, and has received a lot of attention since the first observations in 1970. here   we review the recent advances in the study of this phenomenon in a variety of atomic systems.
the proplyds @xcite are low mass ysos that are being exposed to an intense ultraviolet radiation field which renders them visible. in orion,   there are approximately 160 proplyd objects which are being photoionized mainly by @xmath6 ori c, an o6 spectral type star.   most of them share the same features : a bow - shaped head that faces the ionization source, a tail that is primordially directed away from the source, and a disk, sometimes seen in silhouette against the hii region. here   we use 2d hd simulations with a treatment of the radiative transfer@xcite to calculate the mass loss rate of the sub- or trans - sonic wind ( if ) of the pro plyds. for the first time  , we show that the if of these objects is strongly model dependent and that the acceleration of the if depends on the distance from the ionizing star. as the flux of far ultraviolet radiation ( fuv ) photons dissociates the molecules in the disk of the Proplyds, the if is accelerated at the pro Plyd s ionization front ( if).we find that the calculated mass loss rates of the
we propose a new method for early stopping the computation of feature evaluations for uninformative examples by connecting the perceptron algorithm to sequential statistical tests.   this connection results in a general method that makes margin based learning algorithms attentive, which means that they have the ability to quickly filter unimportant examples without fully evaluating their features.
hard x  ray emission from scorpius x1 ( sco x1 ) is observed in the @xmath120220kev interval in the high energy x - ray timing experiment ( hexte ).   we used data from the hexte to search for a non  thermal component in the power law spectra, and data from proportional counter array ( pca ) to determine the z position of sco X1. using our data sample of 185,672s of hexte live  time and more than 100ks of on  source live   time, we find that the presence of a hard x  rays tail in sco y1 is present in the@xmath2.521.0kev range.    we also find that there is a non - thermal component with a peak at ~30kev in the rxte archive histogram mode data, which are accumulated every 16s, and this component is not detected by high sensitivity searches.
diffractive deep inelastic scattering ( ddis ) is a powerful tool for probing the soft and semihard regimes of hadronic processes with a hard scale.   it is characterized by a leading proton carrying most of the beam momentum and a well separated produced hadronic system, which is well separated from the proton s original momentum transfer from the electron. here   we explore the interplay between hard and soft physics in this process using the data from the hera @xcite experiment at the tevatron to investigate the role of soft interactions in the formation of the hadronic final states in diffractive events.    we find that the dynamics of the soft part of the process are dominated by soft exchanges of quarks and gluons via pomeron exchange, whereas the hard part of an event involves a large momentum transfer of the lead proton from its bound state proton to the emerging hard - scattered partons, which interact with it through the confining string - like color field and may be driven by the exchange of color charges between the two interacting partons. as the number of exchanged partons increases, the density of the main proton decreases, and the topology of the conf
the polarization interferometer @xcite is proposed for the measurement of the displacement field of a thermally loaded micro - cantilever.   the optical phase induced by the sample - wollaston prism group and the measured intensity is studied, and the twofold origin of the optical phases is detailed. an inversion method developed to convert an optical phase change into an out - of - plane displacement is presented. as a consequence,   a shot - noise limited detection is described, and a method for the inversion of an opticalphase change into a displacement is also presented. finally, an example is provided on the use of this method on the measurements of the displacements of a thermo - loaded micro-cantilever using a multichannel nomarski microscope@xcite.
theory of many interesting classes of finite structures with bounded tree - width is decidable by monadic second - order logic ( @xmath6-theories ).   the same holds for many classes of ( finite or infinite ) relational structures with a decidable @x Maths2-theory. in the present article   we classify these classes according to their ` combinatorial complexity'and compare them via transductions, a certain kind of interpretations suitable both, for monadicSecond-order logic and, using a detour via incidence structures, also for guarded second - place logic (@xmath10).we show that the two approaches are equivalent and give rise to the same hierarchy.. this indicates the robustness of our definitions and their intrinsic interest.
the inverse ising problem is a central issue in system modeling : it is the problem of inferring the values of the coupling constants of a general ising model from the correlation functions of the model.   various techniques have been developed in order to solve this problem : two general approaches which can be flexibly adapted to the specific problems are bayesian model comparison and boltzmann - machine learning. in this paper   we present explicit analytical formulas to exactly perform the inversion for one - dimensional ising systems having general multispin interactions, i.e., those systems with two - body interaction and external field. using these formulas we show that the results obtained using our method are comparable to those obtained using other approximate methods, e.g., monte carlo optimization, message passing based algorithms and thouless - anderson - palmer equations.
the crossover from thermal to quantum tunneling of the magnetization(qtm ) has been studied intensively in the presence of dissipative effects of the environment.   it has been demonstrated that the qtm can coherently tunnel between the degenerate minima of magnetic energy at low enough temperature, and the escape rate of the ground state tunneling is independent of temperature. here   we study the crossover from the classical thermal to the quantum regime of the Qtm in aqueous solution using functional integral approach. for the first - order transition,   the barrier height decreases from the top of the barrier to the bottom of the potential with lowering temperature, while for the second - order one the barriers are more favorable at high temperature. by taking into account the experimental results, we find that the escape rates of the two types of transitions are the same for both types of systems.
weak measurement @xcite is a kind of quantum measurement where the coupling between the measured system and the measuring device is so weak that the system remains unaffected during the process of measurement.   it is argued in some recent papers that this conclusion may not be correct. here   we show that, although the method of weak measurement provides a very different angle to view quantum systems, both its mathematics and internal essence obey the usual approach to quantum mechanics. for the same quantum system, without the post - selected state, quantum mechanics provides us the probabilities associated with observable quantities. even when a weak measurement is made in a post -selected system,   the probability of finding the photon at position e is non - zero no matter how weak the measurement is.graphical abstract
pion multiplicity distribution and its associated fluctuation and correlations have been of interest for several reasons.   a well known procedure for studying correlations using the bose - einstein symmetries associated with pions in a hanbury brown - twiss analysis @xcite has been recently solved analytically by t. csrg and j. zimanyi. here   we present a generalized statistical model based on a grand canonical partition function for the study of nuclear multifragmentation distributions, nuclear liquid - gas phase transition, critical exponent, intermittency, and chaotic behavior of particle production which is based on the identification of clusters of size @xmath5 and the cycles of length @x Math5 in a permutation. to study the properties of these clusters, we show the importance of the fisher critical exponent and relate it to one of the main parameters called @x math0 in our approach. moreover, taking special values of@xmath0, or equivalently @x maths3, reduces our unified model to various specific cases that are frequently used in particle production phenomenology such as thermalization, critical point fluctuations, fluctuations from a first order phase transition ( at rhic ), charge particle
exact solutions of the einstein equations are very important tools for understanding the meaning of general relativity.   they combine tractability with nonlinearity, so they make it possible to explore nonlinear phenomena while working with explicit solutions, and as we shall see below, they have had considerable impact on the theory. in this talk   i give a brief overview of the current state of knowledge about exact solutions and illustrate the crucial role they have played in the development of our understanding of the theory itself.
z  canis  majoris ( z  cma ) is a luminous and irregularly variable young stellar object ( yso ) originally classified as a herbig  ae / be star ( haebe ) on the basis of its emission line spectrum and association with reflection nebulosity @xcite.   it underwent an outburst lasting a few months in 1987, during which its spectral characteristics drastically changed and its visual brightness increased by a modest @xmath1 magnitudes. to explore the level of extended emission present at spatial scales intermediate between the very narrow interferometric beams and the large scale nebulosities known to surround these systems, we observed z  Cma on 2001  january  11, using the adaptive optics ( ao ) system at the keck - ii telescope . for all frames the correlated double sampling ( cds ) readout mode was used. in order to search for circumstellar emission beyond the normal field of view of the slit viewing camera ( scam ) array in ao mode, we recorded 4 such frames nodding the telescope around a square by offsets of@xmath13, which resulted in a total field of views in the combined image of @x
the fractional quantum hall effect, which describes the ground state of a many body system in a quantum hall state, can be realized by simply rotating and cooling atoms confined in a harmonic trap.   this approach yields a stable ground state separated from all excited states by an energy gap, but in practice this gap is rather small because of the weak interactions among the particles in the magnetic traps typically used. in a recent paper @xcite, it was shown that it is indeed possible to realize the fqh effect in an optical lattice, and that the energy gap achieved in this situation is a fraction of the tunneling energy, which can be considerably larger than the typical energy scales in a magnetic trap. in this paper, we study the effects of the lattice structure on the existence of quantum states with fractional statistics in trapped bose - einstein condensates ( bec s ) and show that the results are consistent with the predictions carried out in ref. for a single particle,   the lattices modify the energy levels from being simple landau levels into the fractal structure known as the hofstadter butterfly@xcite. furthermore, we show that adding dipole interactions between the atoms can
the cluster of galaxies is one of the hottest, most x - ray luminous clusters known. since its discovery by @xcite, it has been the subject of intense and ongoing research.   the goal of this work is to obtain a high - resolution, absolutely calibrated mass map with no assumptions on the physical properties of the underlying cluster potential. for this purpose   we use hst acs data, incorporating the gravitational lensing information from both multiple image systems ( strong lensing ) and from distortions of background sources ( weak lensed ). using positions and redshifts of the strongly lensed images and the shape measurements of the " weakly " lensing sources, we perform a combined strong and weak lensing mass reconstruction, thereby significantly improving the constraints on the mass and positions of the main cluster and the colliding subcluster of.
the skyrme model @xcite is a nonlinear effective field theory of weakly coupled pions in which baryons emerge as localized finite energy soliton solutions.   the stability of such solitons is guaranteed by the existence of a conserved topological charge interpreted as the quantum baryon number @xmath5. in the lowest nontrivial topological sector, the skyrmion is described by the spherically symmetric hedgehog ansatz which reproduces experimental data with an accuracy of@xmath8 or better @xcitesite. here  , we propose a static oblate solution based on rational maps to describe the axial deformation of the @x Math0 soliton in the same way as the rational map ansatz proposed in @xcitedite. from this work,   we show that the radial dependence of the soliton shape function is decoupled from the angular degrees of freedom and that the profile function can be defined as a function of both radial and polar degree of freedom.. the results are compared with the results obtained for the corresponding wild - type ab initio ansatz, which is based on the instanton - inspired ansatz
charge transport in dna based oligomers has been the subject of considerable research interest for the past two decades.   however, the experimental properties of dna - based molecules are still controversial, with several experiments revealing quite controversial results ranging from insulating to semi - conducting and even metallic - like behavior. here   we review the current knowledge on the charge transport properties of g4-quadruplexes, which are formed by either one, two or four g - rich dna strands in a parallel or anti - parallel orientation, and are known to play an important role in some biological processes such as in telomeric dna regions, where they inhibit telomerase and hiv integrase. additionally, these molecules are also known to interact with various cell proteins that cause diseases like bloom s and werner s syndromes, i.e. cytotoxic towards tumor cells and therefore, might be a key for the design of anti - cancer drugs. despite the wide range of experimental conditions and the different base sequences of the studied base sequences,   most of the theoretical studies have focused on the conduction properties of single - stranded dna ( dsdna ), while the structural and electronic
we have studied the polarization of soft x - ray selected active galactic nuclei ( agn ) from the rosat all - sky survey.   we have complete polarization data for 65 objects, and compared them with those from the optically selected narrow - line seyfert 1 galaxy ( nlsy1s ) sample that goodrich ( 1989 ) studied by spectropolarimetry. in both cases,   the distribution of the degree of polarization is similar to that of the goodrich sample, but it is biased towards optical properties, e.g. cold absorption.
in many scientific applications, we need to solve lower triangular problems and upper triangular problems, such as incomplete lu ( ilu ) preconditioners, domain decomposition preconditions and gauss - seidel smoothers for algebraic multigrid solvers @xcite. the algorithms for these problems are serial in nature and difficult to parallelize on parallel platforms.   gpu is one of these parallel devices, which is powerful in float point calculation and is over 10 times faster than latest cpu. recently, gpu has been popular in various numerical scientific applications. in this paper, we introduce our work on speeding triangular solvers for gpu using a new matrix format, hec ( hybrid ell and csr ) ; this matrix format includes two matrices, an ell matrix and a csr matrix that are in column - major order and is designed to increase the effective bandwidth of nvidia tesla gpu. based on these modified algorithms, ilu(k ), ilut and domain decompositions ( restricted additive schwarz)preceditioners   are developed. also, parallel algorithms for solving the triangular systems are developed.the algorithms are motivated by the level schedule method described in
the averaged null energy condition ( anec ) is investigated for the equilibrium hartle  hawking vacuum state in the conformally - coupled massless scalar field on schwarzschild spacetime.   the results show that the anec is violated whenever the background spacetime has a non - conformal couplings, massive scalars, or reissner   nordstrm geometries. as a consequence,   it is possible to obtain self - consistent solutions to the einstein field equations for all of the energy conditions.
In this article, we present a list of the most important papers in the field of chemical biology published in the journal of experimental chemistry since the beginning of the 20th century.   the number of papers on chemical biology has increased dramatically over the last 50 years and is now more than 4000.see research articles http://www.biomedcentral.com/1471-centuries/1741-chemical-biology/40004000 for a complete list of all the papers that have been published in order to date on the subject.
the synchrotron radiation emitted by electrons passing through a dipole bending magnet is used in the na64 experiment at cern to distinguish between electrons and heavy charged particles.   the standard technique of detecting cherenkov radiation to distinguish them is very inefficient at energies of 100 gev @xcite. here   we present the results obtained with this method using the bgo detector employed in na64, a fixed - target experiment at the cern sps electron beam line at the h4 sps ( ~100 gev ) which uses an active beam dump and missing energy techniques to search for rare events predicted in dark sector models. as will be shown, our results have a very good overall efficiency 95% and 3 orders of magnitude better rejection factor than previously reported using a similar scheme @xcites.
the notion of graph - like legendrian unfoldings was introduced in @xcite.   it belongs to a special class of the big legendrian submanifolds which zakalyukin introduced in@xcite, and it is useful for applying to many situations related to the theory of lagrangian singularities ( caustics ). in this survey   we give in this section detailed proofs as an aid to understanding and applying the theory.
the finite difference - time domain ( fdtd ) method, originally introduced by kane yee @xcite to solve maxwell s equations, was for the first time applied to solve the three - dimensional dirac equation.   the dynamics of an electron wave packet under the influence of a vector potential is studied using updating difference equations and the solutions of the time - dependent Dirac equation in the fd td method are presented. as a manifestation of quantum mechanics, charged particles passing around a long solenoid can feel a magnetic flux even when all the fields in the region through which the particles travel are zero. since,   classically, there are no forces acting on the charged particles in the zero field region, the theoretical description of the aharonov - bohm effect contains a number of assumptions. while there is still an open question on the presence or non - existence of classical forces responsible for the ohm - bhm effect, on a macroscopic level   they have not been observed in the case of@xcite.
the @xmath0  bootis stars are late b to early f - type populationi stars, which show a peculiar surface abundance pattern : while the light elements ( c, n, o and s ) are roughly solar, the fe - peak elements show underabundances of up to a factor of 100.   the abundances are ascribed to diffusion in the presence of slow rotation ( am stars ) or strong magnetic fields ( ap stars ). here   we present a detailed analysis of the interaction between a star and a diffuse interstellar medium ( ism ) cloud as an explanation for the @x Math0  Bootis phenomenon.    we show that the ism dust particles undergo rutherford scattering off the star and hence never approach the star closer than its avoidance radius. at these low densities   dust and gas are also not effectively coupled via collisions.
strontium titanate ( srtio@xmath0 ) undergoes an antiferrodistortive ( afd ) transition as the temperature drops below about 105  k@xcite.   this is due to a softening of the lowest frequency triply degenerate zone - corner r - point vibrational mode of lowest energy. in this mode,   the sr and ti atoms remain fixed, while the oxygen octahedra rotate about one of the cubic axes passing through the ti atom. with decreasing temperature, however, the static dielectric constant saturates at a high value, and the material does not become ferroelectric even at the lowest temperatures.the present work is concerned with the wavevector dependence of structural instabilities in srtialite, obtained from first - principles calculations, and their interpretation in light of previous similar calculations on knbo@x Math0.
we report a possible uv luminosity dependence of ly@xmath1 emission of lyman break galaxies ( lbgs ) at @xmath2 using our previous and new spectroscopic sample together with those from the literature, and we discuss some possible causes.   the results are based on observations and data reductions taken with focas @xcite attached to the subaru telescope and the goods - n and j0053 + 1234 fields of the @x Math2 observatory. for the latter one,   9 bright lbgs were found, and 2 faint ones were identified with a strong low - ionization interstellar absorption line near the redshift of about @xMath12 km s@x math13 relative to the interstellar absorption lines in a part of them, which suggests the presence of an outflow in the lbgs at #xmath3.    for the former one, the redshifts are much smaller than those seen in the literature ; however, they are still large enough to explain the observed spectral energy distribution of the emitted light..the redshift is most likely due to the existence of a star formation rate of about 1.5 times that of the universe at the epoch
double beta decay is of a major importance both for particle and nuclear physics. in particular, the lepton number violating neutrinoless mode of double beta decay ( @xmath11-decay ), forbidden in the standard model(sm ), touches upon one of the key questions of particle physics : if massive neutrinos are majorana or dirac particles.   the development of reliable models for calculation of the corresponding nuclear matrix elements becomes more and more challenging problem of nuclear physics as the experimental data@xcite and the results of theoretical analysis @xcite support the conjecture that the single state dominance ( ssd ) hypothesis is valid for two - neutrino accompanied doublebeta decay. here   we present a phenomenological approach based on the ssd hypothesis to the calculations of the @x math12-decays with @x Math16 ground state of the intermediate nucleus from the quasiparticle random phase approximation ( qrpa ) of ten nuclides @xaite, including decays into two excited states ( ~20 mev and ~30 mev ), which have been directly observed in ten Nuclides [ @x maths6,7, 8, 9, 10,
the effects of polymer additives on the heat transport in the bulk of turbulent rayleigh - bnard convection ( rbc ) were studied in a cylindrical convection cell with aluminium rough top and bottom plates coated with a thin layer of teflon.   the experiments were carried out using a small thermistor combined with a two dimensional laser doppler velocimetery ( ldv, dantec dynamics ) to measure the local nusselt number at the cell centre in the range of @xmath13 and@xmath14.the results show that the thermal boundary layer - dissipation dominated regime of turbulent rbc is bulk - dominated in convection cells with rough surfaces compared to those in the cases with smooth surfaces, which motivates us to carry out experiments in the rough cell. however, the temperature and velocity fluctuations between the two regions of the cell are not significantly different when the cell is heated from below and cooled from above. for the bulk region, the observed enhancement of the heat flux in the presence of polymers is due to the stabilization of the thermal barrier layer, which reduces the emission of thermal plumes, and hence the global nusselslt number.
the search for solar - like oscillations in stars has experienced a tremendous growth in recent years.   most of the results came from high - precision doppler measurements using spectrograph such as coralie, harps, ucles, uves. in this paper   we report the detection of excess of power, providing evidence for oscillations, in the g5 subgiant ( hr  6623, @xmath4, g5  iv ), a slightly evolved solar - type star with mass @x Math5, effective temperature @x math6, and @x maths7.. the observations were carried out over seven nights ( 2006 june 1319 ) with the high resolution cross dispersed echelle spectrographic sarg ( @xcite ) mounted on the italian 3.6 m telescope tng at la palma observing station.    the observed spectrum was fitted with a reconstructed one, by using a convolution between the oversampled stellar template, the very high resolution iodine cell spectrum and the measured spectrograms instrumental profile. 	 the amplitude spectrum of the velocity time series was calculated as a weighted least - squares fit of sinusoids @xcites
the universe appears to be going through an accelerated phase of expansion.   the acceleration is reported to be a recent affair, started well within the matter dominated regime and has set in after a long stint of decelerated exapnsion. among a host of alternatives,   a quintessence field attracting a lot of attention is the use of a scalar field which is minimally coupled to gravity and endowed with a potential.. the idea is that the potential may give an effective negative pressure which would result in providing the required anti - gravity effect and thus drive an accelerated expansion. here   we present a dynamical systems analysis of the solutions for frw cosmological models with a pressureless fluid and a tracking quintessentence field. using the equations of state and the equation of state parameter, we find that only one generic fixed point can be obtained, which depends on the fractional rate of decrease of the quintessences potential. this fixed point is a function of the density of matter or radiation at the level of the dark matter but is not the same as the energy of the current acceleration.
the caltech faint galaxy redshift survey ( cfgrs ) is working on two fields.   the first field at j005325 + 1234 measures @xmath4  arcmin@xmath1 with a statistical sample containing 195 infrared - selected objects complete to @x Math5  mag.  in the second field at hdf - north, the spectroscopy is 92% complete and the sample of objects with redshifts in the region of the hdf now exceeds 660. here   we focus exclusively on the issue of galaxy clustering in these samples. using a gaussian kernel smoothing to define groups, we show that there are bound groups of galaxies in both fields which are separated by up to 30 arcmin from the main field. as a function of the size of the sample,   most of the groups are larger than 1.5  km  s1 and the largest groups are more than 2.5 times more likely to be supernumerary than the smallest groups.    the results are consistent with the notion that the universe is organized into discrete clusters.
weakly interacting massive particles ( wimps ) in the mass range 30 gev to 3 tev are expected to annihilate slowly in galactic halos.   the brightest source of wimp annihilation radiation is expected to be the galactic center ( gc ), where they are most concentrated. here   we show that there is only a narrow window in which dark matter annihilation could be discovered at the gc, given the hess source and its extrapolation below 100 gev for the microwave background anisotropies @xcite and the power spectrum of density fluctuations on galactic scales @xmath1. as a pseudoscalar particle,   wimp annihilation is isotropic, and the observed spectrum from a source will have this property if the pion distribution is isotropy of the decay implies that the photons emitted by the source are uniformly distributed, and thus the spectra are constant between the minimum and maximum energies. using the darksusy model, we find that the photon spectra from annihilations of pairs of self - conjugate dark matter particles to pairs of quarks are non - relativistic, giving monochromatic quarks with energy@xmath17
the dynamical mean field theory ( dmft ) for the hubbard model of actinides @xmath1 and its cluster extensions @xcite is a powerful tool for studying the physical properties of materials with strong correlations.   the recently developed quantum monte carlo method for the impurity solver of this model has been extended to treat all interaction terms : hubbard, hund s coupling and spin - orbit coupling. in this paper   we describe the new implementation of the method for applications to many realistic materials with complicated multiplet structure, including clusters of few sites and superconducting states. using the new method, we show that it is possible to predict the low temperature coherence of both the t - j and hubbard models with high precision and accuracy at the strong correlation limit of > 1.5  kj / cm2 in the range of ~0.8 to ~3.4  kv. by applying the method to the complex multi - site model of cerium, the kondo volume collapse transition in elemental cerium will be reexamined and the valence histogram of the alpha and gamma phase of the material will be studied.
the beta function of @xmath0 supersymmetric yang - mills ( sym ) theories has been a subject of controversy in both non - perturbative and perturbation calculations.   one of the controversies is the origin of loop contributions to the beta function which are not constrained by the adler - bardeen theorem. within the supergraph approach to supersymmetry, along with on - shell infrared divergences of yang-mills theory, additional off - shell ultraviolet divergencies appear @xcite which must be consistently separated from ultraviolet ones before renormalization is effected. in this contribution   we aim at shedding some light on these subtleties using an automatically invariant, four dimensional ( minimal ) framework in which neither ward identities need to be imposed as constraint equations nor modifications in the original physical lagrangian are performed.
we present the first quantum mechanical calculation of screening effect by bound electron in @xmath4 nuclear fusion from the pp - cycle in the sun.   the screening effect is treated within the framework of the adiabatic approximation, which comes from the well known born - oppenheimer ( bo ) approximation and is based on the continuum energy spectrum of the fusing nuclei colliding with the relative momenta of the charged nuclei at the center - of - mass frame. for the case of bound electrons,   it is shown that the screening effects are negligible at low and moderate energies, but dramatically increase when the energy of the beryllium neutrino is reduced to a very low level.
the transmission function of the power law incidence rate, i.e., the number of new cases per time unit, is one of the most widely used transmission functions in epidemiological models.   it is usually assumed that the transmission function is a simple bilinear or proportional mixing transmission function, which follows from the assumptions of random contacts, host homogeneity, and application of the law of mass action. here   we show that power law transmission function can be not only postulated but also derived using a simple heterogeneous intra - individual contact model ( si ) with a non - linear transmission function. under the heterogeneous assumption that the subpopulation of susceptible hosts is heterogeneous,   the density of susceptibles at time @xmath14 having parameter value @x Math15, which determines the transmission coefficient, the transmission relationship between the transmission coefficients and the population size @x math16 is found to be an effective means of derivation of the transmitted incidence rate. by incorporating this transmission function into the model, we obtain a mechanistic heterogeneous si model that is equivalent to a homogeneous one, e.g., with respect to the assumption of constant population size, but without the need for the use
we study self - organization of layered structures in the spinodal decomposition process in the pbte / cdte immiscible material system by kinetic monte carlo simulations of the model at different temperatures and growth conditions.   we show that the elongated structures build in time and as a effect in the space, beginning from the first grown, bottom multilayer. as an effect we obtain characteristic structure of gradually changing morphology of the sample from bottom to top.    the model explains within one picture all phenomena that are observed in the growth of pbme / cdme superlattices.. the mechanism of the observed process of creation of zero, one - dimensional structures is discussed.
with the recent availability of high - quality data for a broad range of performance metrics in many sports, it is now possible to address questions about measurable aspects of sports competitions that were inaccessible only a few years ago.   we analyze play - by - play data for four seasons of all national basketball association ( nba ) games and find that a simple random - walk model successfully captures many features of the observed scoring patterns.    our results suggest that the evolution of the score difference between two competing teams can be accounted for by a continuous - time random walk.
high precision doppler spectroscopy is an important tool to investigate many astrophysical processes in the universe.   the radial velocity ( rv ) precision of @xmath3 cms@xmath2 or better is required to address many compelling science cases including the detection of terrestrial - size planets around sun - like stars. despite averaging the shift over thousands of spectral lines, the best rv precision obtained from traditional sources is limited to @x Math4  ms@x math2. a simple and cost effective approach to produce reference spectra is to use cavity resonance lines of a femtosecond etalon ( fp ) as a wavelength reference. here   we describe the design and construction of a broadband laser frequency comb ( lfc ) that can be used to extract the rv signal from time series data of a high resolution echelle spectrograph under thermovac conditions. using the lfc, we have achieved rv accuracy of ~1.5  ms  ms for the whole spectrum of a star in visible / nir band with a precision of ~0.6  ms at the wavelength range of ~8500  nm. by using this method,   it is possible
we present a detailed analysis of the top quark production near threshold at the cern large hadron collider ( lhc ) using next - to - leading order ( nlo ) cross section formulae in the framework of non - relativistic qcd ( nrqcd ).   the calculations are based on the hard contribution of the first - state radiation and the soft gluon resummation which enhances the cross section by a few per cent when the top - anti - top quarks are moving with small relative velocities. for the first time   we show that the green s function governing the dynamics of the would - be boundstate can be used as a building block for the calculation of the nlo cross section for the top Quark threshold.
the high - density behavior of nuclear symmetry energy in relativistic heavy - ion collisions is studied using the sub - threshold meson of mass 547.853 mev / c@xmath6 @xcite as a probe for the possibility of producing the neutral vector u - boson ( dark photon ) introduced in the super - symmetric extension of the standard model ( sm ).   the results are compared with experimental data from the taps and hades collaborations and with transport model calculations to show that the @xmath2 and the slope @x Math2_{\rho_0}$ ] at normal density are indeed sensitive to the high - densities of the symmetry energy, although comparisons with limited data available are still inconclusive so far.
infectious disease transmission is a branching process in which each infected individual in a given generation of infection produces some number of infected individuals in the next generation, as described by a probability density function.   this picture is particularly apt in the early stages of an outbreak, when the proportion of susceptibles is almost 1 and the process is highly stochastic. here  , we use branching process - type arguments to develop a mathematically rigorous methodology to predict the impact of vaccination on the branching processes of infectious disease transmission and vaccination.    we show that the proposed method can be applied to the mathematical modelling of disease transmission using a classic galton - watson branching process approach. for the case of vaccination,   the model is more complex, as it takes into account the effects of the number of vaccinated individuals and the probability distribution of the secondary infections produced by each vaccinated individual. however, the results are similar to those of the classical branching process analysis of transmission, with the exception that the effect of vaccination is different from that of transmission because the vaccine is not introduced at the beginning of the epidemic.see research article http://www.biomedcentral.com/1741-7007/1471-7006
large - scale mergers are thought to play an important role in the evolution of massive galaxies, but their importance is still uncertain.   we use a deep @xmath17deg@xmath18 multiwavelength survey to determine pair fractions between galaxy pairs from the ukidss ultra - deep survey ( uds ) dr8 k - band mosaic and the uds dr1 data release 8 and supplementary data to estimate the rate of galaxy pair fraction evolution at high redshifts. using this method, we find that the average size of quiescent galaxies increases smoothly with time, whereas the size of large - scale galaxies continues to grow rapidly at lower redshifting. here   We discuss the implications of these results for the evolution process of galaxy formation.
the exotic binary system  (= v615 cas = gt0236 + 610 ) is a highly variable radio source which exhibits periodic radio outbursts with a period of @xmath5d ( @xcite ).   the source shows evidence for rapid expansion ( @x Math11 km / s ), but not for relativistic bulk motions such as those seen in grs 1915 + 105, gro j1655@xmath1240, ss433 and cyg x-3.. the source is also associated with a weak, variable x - ray source which has been observed with _ einstein _, _ rosat _, and _ asca _ ( @xaite ) during the radio quiet phase. here   we report the results of dual - frequency radio monitoring observations of  to follow the radio flux density and spectral index of the source during its emission at wavelengths from radio to x - rays and probably @x math4-rays.    the observations were made several times per day ( with a few gaps ) from 1994 january 27 to 1996 february 23 using the national radio astronomy observatory green bank interferometer in green bank, west virginia.
the influence of the temperature and chemical potential on the color superconductivity ( csc ) phase transitions in dense quark matter with a finite chemical potential is investigated in the framework of the nambu  jona - lasinio model ( njl ).   the influence of external electromagnetic and gravitational fields on the csc phase formation is studied at lower values of the chemical potential @xmath3 mev, and the effect of the thermalization effect of acceleration on the phase transitions is investigated. for a uniformly accelerated observer, the broken color symmetry in csc is found to be restored by the combination of curvature and temperature.
photospheric changes during large flares have been studied successfully by @xcite.   most of these observed changes are located in the penumbra of the sunspot. since, flares are driven by magnetic energy changes, the most promising locations to look for flare related changes are the regions between umbra and polarity inversion line ( pil ). here   we use high - resolution filtergrams of a flaring @xmath0-sunspot in noaa 10930 on 13 december 2006 using filtergraph ( fg ) instrument onboard hinode spacecraft to investigate flare - induced changes during a x - class flare. at 180@xmath6 azimuthal ambiguity using   stokes inversion of the spectra obtained by spectro - polarimeter ( hinodes / sp ) instrument under milne - eddington approximation, the coherent motions of the filaments are observed in the vector magnetograms of the solar optical telescope ( sot ) during the flare interval. from the observations,   it is found that the helical filaments move in a straight line along the photospheric axis, e.g. lateral motion and/or twist, while the rotational filaments
the apparent variability of two steep - spectrum, low - frequency - variable ( lfv ; @xmath7 1 ghz ) radio sources at 320mhz has been investigated.   the source 0235@xmath3197 and 1203@x Math4043 show a linear polarization of the emission plane which could be caused by changes in ionospheric faraday rotation relative to the linearly polarized e - w arm of the northern cross bologna telescope.
the origin of hadronic cosmic rays ( crs ) is a major unsolved puzzle in physics.   recent observations do not confirm some expectations in the currently accepted framework for hadronic cr origin, where cosmic - ray nuclei with energies below @xmath0 ev ( the " knee" ) are accelerated in galactic supernova remnants ( sns ), and those above@xmath1 ev ( The ankle ) are unlikely to be accelerated in sources far beyond our galaxy. here   we explore the possibility that the observed anomalies are first indications that the current framework for the origin of Hadronic crs is wrong, and propose an alternative origin.
inflationary cosmology, introduced by guth @xcite, remains the main point of view in modern cosmology.   it is important to suggest the model that describes correctly the inflationary epoch in accordance with the experimental data. here   we pay attention to @xmath0-gravity theories and the modification of the general relativity ( gr ), replacing the ricci scalar in einstein - hilbert action by the function @x math0. a single extra degree of freedom ( a scalar )   is replaced by a scalaron in the gravitational field and the scalar - tensor form is reformulated in a Scalar - Tensor form. if the @x Math0 gravity really describes the evolution of our universe, the present and primordial dark energy ( de ), it should follow from the fundamental theory like string or m theory. for this purpose, we consider the choice of the function corresponding to the functions corresponding to ~5, ~6, ~7, ~8, ~9, ~10, ~11, ~12, ~13, ~14, ~15, ~16, ~17, ~18, ~19, ~20, ~21,
we present a different approach to investigate the average pulse width of gamma - ray bursts ( grbs ).   we use light curves of 1186 batse grb light curves in 4b catalogue to study the bimodal distribution of the duration of grbs. using the auto - correlation coefficients of the light curve of each grb, we calculate the average pulses width @xmath1 of each burst and study the distribution of this number of bursts by comparing the results with the data from earlier studies. for the short - pulse bursts,   the mean pulse width is longer than that of the bright long-pulse bursts. however, it does not show a simple relation with the grb peak flux.
the charge of weak polyelectrolytes ( pes ) is determined by the probability of each functional group to dissociate and expose a charged residue.   this probability depends on a chemical equilibrium which can be tuned by varying the ph of the solution. in this paper   we consider stiff pes, where there is no coupling between the dissociation degree of freedom and the polymer conformation. using a mean field theory with explicit symmetry breaking between two sublattices  , we show that the average charging and free energy as function of the distance between the polymers are well described by a non - uniform mean - field approach. for a single weak pe in salt solution,   the exact form of the average charge depends on the salt concentration, and also on the dielectric properties of the polymer backbone, as will be discussed below.
the mass differences between the first two massive elementary particles i.e. a muon and a neutral pion have been found to be close integral multiples of the mass difference between them. in the present study  , we evaluate the applicability of this result to the baryon and meson multiplets.   we reveal that the symmetry broken mass splittings of the hadrons are close integrals of the observed value of 29.318 mev which is the closest integral multiple of the predicted value from the best - fitting formulae based on the su(3 ) symmetry for the masses of the two classes of hadrons with spin j and parity p such that @xmath1=@xmath2@x maths0 are : @x Math1=938.27203 mev, @x math4=939.56536 mev or @xMath5=1115.683 mev depending on the spin and parity of the octet baryons. however, it is observed that the mass gap between the successive members of the pseudoscalar meson and octetbaryon multiplet is about 14.264 mev larger than the expected value
abstractin this paper, we consider perturbations to a background schwarzschild spacetime which is described covariantly in terms of three non - vanishing locally rotationally symmetric class ii scalars @xcite.   the first - order geometric and kinematic quantities governing these scalars arise from both the bianchi and ricci identities. using the recently developed   _ 1 + 1 + 2 covariant two - sheet formalism, we derive two decoupled wave - like equations for complex spin - weighted@xcite scalars that are a covariant representation of the bardeen - press ( bp ) equations. upon inspecting the fully non - linear equations  , we note that the successful decoupling method described in @excite is also suitable for the system that arises here.see research article http://www.biomedcentral.com/1471-2148/7/9/11/8/17.
winbioinftools is a toolkit containing a number of bioinformatics software tools running under windows hpc cluster 2008.   the tools include coconut, which is used for comparing whole genomic sequences, blast, which are used for searching biological databases, and blast, an implementation of the standard sequence alignment algorithm. in this paper   we discuss how the tools mentioned above were ported to run under windows and how they were adapted to run over the cluster architecture. moreover, we present some experimental results showing that the performance of the tools on a cluster is superior to that on a single machine. furthermore, we report results about comparing the performances of the windows based versions of these tools to the corresponding linux versions.
long - range beam - beam interactions are known to cause emittance growth or beam loss in the tevatron @xcite and are expected to deteriorate beam quality in the lhc.   compensation of these interactions by applying external electromagnetic forces has been proposed for the lHc. during the kloe experiment in da@xmath1ne,   an improvement of beam lifetime without luminosity loss due to the compensation of parasitic collisions has been observed. in this report   we discuss the results of numerical simulations of a wire acting on a beam in rhic using a multi - particle tracking code and compare them with measurements in run 7 and 8 of the rhic collider.
periodic potentials created by optical lattices are a powerful tool for controlling and manipulating nonlinear matter waves through dynamical diffraction management.   one of the important implications of such management is creation of nonlinearly localized matter - wave packets, the so - called  bright atomic solitons, in a  bose - einstein condensate with a positive scattering length, i.e. with repulsive inter - atomic interaction. here  , we examine the problem of mobility and interactions of gap Solitons in a one - dimensional optical lattice without an additional harmonic confinement, within the framework of the continuous gross - pitaevskii model with a periodic potential. as the chemical potential of a bec scans the spectral gap, the gap soliton scattering properties range from those of " ideal "solitons without a periodic current to those of nonlinear localized excitations of discrete nonlinear lattices. using the inelastic collisions of near - the - band - edge gap solatons, we show that the gap solution can provide reliable means for generating highly - localized high - density immobile atoms in the depth of the spectrum.
the magellanic system is extremely rich in extended objects, i.e. star clusters, associations and emission nebulae.   the present study has several perspectives : ( i ) using colour - magnitude diagrams ( cmds ) to study the radial density profile of clusters and relatively small associations in the inter - cloud bridge ; ( ii ) providing the age and density distributions of the different stellar aggregates and infer a scenario for the cluster and association formation and evolution in the bridge, under the enduring action of tidal forces from both the smc and the lmc ; ( iii ) estimating the age of the star clusters and associations at the bridge border using self - consistent parameter analyses recently applied to smc star clusters ; and ( iv ) comparing the results of the present work with those of the literature.
velocity - strengthening friction is a recently discovered property of frictional interfaces.   it has been shown that for a broad range of materials friction is velocity - weakening under steady - state sliding conditions, but for higher slip velocities, friction generically becomes velocity - strengthener. here   we study the effect of this behavior on spatiotemporal interfacial dynamics, energy dissipation and radiation, and the global interfacial strength, with a special focus on the nucleation, propagation and arrest of rupture fronts. using three variants of a realistic rate - and - state friction law, one which is purely velocity - weaken, one in which the friction crosses over at higher slip speeds to logarithmic friction, and one which crosses over to linear friction, we show that the presence or absence of velocity - Strengthening friction at relatively high slip Velocities can significantly affect theglobal interfacial resistance ( strength ) and the energy released during frictional instabilities ( " event magnitude " ), even under quasi - static loading conditions. different forms of speed - up friction   are found to give rise to events of similar magnitude, yet with dramatically different dissipation / radiation rates due to the wide range of the underlying
this paper outlines a framework for developing and deploying image - based analytics on high - resolution electron microscopy of animal brains.   our focus is design and development of a " full - stack" prototype for deploying analytics in a hadoop map / reduce ecosystem. by " full- Stack ",   we include interfaces and services that implement a pipeline from data download to distributed analytic processing and results output. the project was completed as part of a graduate course at columbia university, called " big data analytics".database url :   http://cloud.ganita.org/images/beddiagram.png    1.
a new numerical method for solving nonlinear volterra integro - differential equations ( vide ) is proposed.   the numerical method is based on a decomposition method proposed by daftardar - gejji and jafari ( djm ) in @xcite, which is generalization of the theorem of existence and uniqueness of integro- differential equations . to obtain a more accurate and faster numerical method with step - size h, we have used a different type of decomposition technique. using this method,   we have developed a numerical method to solve nonlinear vides in a linear multi - step manner.    the numerical results show that the method is accurate and fast enough for the purpose of solving these equations.
topological insulators in free fermion systems host gapless edge / surface states @xcite, which can be a source of various remarkable properties.   recently, pesin - pesin et al. suggested the emergence of a novel topological state in three - dimensional topological insulator systems with electron correlations. according to their analysis based on a slave - boson mean field theory, this new phase hosts gapless modes not in the single - particle spectrum but in the spin excitation spectrum due to the interplay of electron correlations and topologically nontrivial properties in the bulk. in this paper  , we analyze a bilayer kane - mele - hubbard model@xcite with lattice distortion and spin exchange interaction. in the non - interacting case,   the topological phase shows the quantized spin - hall conductivity @xmath0, implying that electrons with up- and down - spin state propagate in opposite direction ( helical modes ) in each layer. using the bosonization approach, we show that in the presence of electron correlation, the helical mode in the individual particles is gapped, while the spin - chern number remains unchanged in the mass.
we derive the field equations for the model of a thick brane with two time - dependent spinor fields having an arbitrary potential energy, and with a cosmological term taken into account.   choosing the special anstze for these fields, the off - diagonal components of the energy - momentum tensor are excluded. in order to avoid this, we add to the model one more spinor field. in this case  , we consider the five - dimensional gravitation with a nonlinear spinor Field as a source of matter. by considering the trapping of a test scalar field to the brane, we find regular solutions of multidimensional field equations with a given material source.
the mass of intermediate susy particles from a fully hadronic final state at the ilc is obtained by reducing the background to a minimum.   this study concentrates on the reduction of the sm background using a few very basic requirements and a kinematic fit to improve separation of the chargino from the neutralino signal. in order to achieve this,   four jets need to be assigned to two gauge bosons, either two charginos or two neutralinos, depending on whether they originated from a decaying chargino or a neutralino. as an example, the process of pair production of charginos and neutralinos from the susy - p5 scenario   is studied. for the first time, it is possible to extract the masses of intermediate Susy particle masses from a complete reconstruction of the final state using the full simulation of the ` ldcprime_02sc ` detector model.
we study the form factors appearing in the inclusive decay @xmath0, in the framework of the noncommutative standard model ( sm ), including the non - commutative effects.   we find that the form factor of the @x math0 decay is created by flavor changing neutral currents at loop level in the standard model. when the non Commutative effect is switched on, new structures with the corresponding form factors arise. for the effective low energy theory,   the nonCommutative scale is chosen by replacing the ordinary products of the ordinary product by the @Xmath12 product.    the form forces of the inclusive decays @x Math0 and @x maths1 are calculated using the method described in the appendix of @xcite. to obtain the results, we have used the cabibbo - kobayashi - maskawa ( ckm ) matrix elements in the ordinary sm as a source for the complex cabib bo - kabayashi- maskawa matrix elements which are involved in the interaction between the quantum field theory and the sm.
the femtoscopic correlation function ( @xcite ) of the quark - gluon plasma ( qgp ) created in pb - pb collisions at center of mass energies @xmath1, 2.76 and 7  tev has been analyzed at the large hadron collider ( lhc ) with the alice detector.   the results are presented for the first time in this work and the comparison of the pp  dataset for all@xmath7 to the heavy - ion collision data, including the central collision point, is also discussed.
the energy gap between unstable d - brane configurations and the stable vacuum should be computable using witten s cubic string field theory ( sft )  . the level truncation scheme of  @xcite has appeared to lead to very good agreement with the expected results in the context of the decay of bosonic d-brane   and unstable d--brane in superstring field theory.   however, it is still not clear why the calculations in the level - truncated sft converge so rapidly to the correct answer for quantities like vacuum energy. a renormalization group ( rg ) analysis of worldsheet theory in first quantized approach can be used to show that the mass of the tachyon lump on a dp - Brane is equal to that of a d(p1)-brane. this leads to the idea that boundary sft as was originally proposed by witten and shatashvili   may efficiently describe open string tachyonic condensation on d -Brane in bosonic string theory. in this paper   we will try to address these issues in the worldsheet approach by choosing the initial tach Lyon profile on a circle on boson d
we present a method for measuring the vacuum component of an optical cavity in an arbitrary quantum state.   we introduce a probe which consists of a three level atom in the @xmath2-configuration, where the cavity mode can be controllably coupled to transition b whereas transition a interacts with an externally applied laser field   @xcite. by measuring the atomic state of the atom in either the cavity or the excited level, we can determine whether the initial cavity state had at least one photon or none in it. using this method, we show that the vacuum is removed from the cavity state without affecting the relative amplitudes or coherences of the other fock states.
the chiral lagrangian of the low energy hadron physics in qcd is derived from the first principles of qcd without taking approximations.   the chiral langrangian coefficients are contributed both by the anomaly part and the normal part of the theory, which are expressed in terms of certain green s functions in Qcd.    the relation between the chirality of the lagrangia and the fundamental principles ofqcd is studied using the following techniques : ( 1 ) the effects of the rotation of the external scalar, pseudoscalar, vector, and axial - vector sources rotated by @xmath4 are related to the nonlinearly realized meson field ; ( 2 ) the effective action of the rotated sources is related to a given qcd green s function ; ( 3 ) the effect of the momentum expansion on the global symmetry of the system can be considered as a function of the rotational order of the shifted sources ; ( 4 ) the influence of the quark functional measure on the origin of the fluxes is explained by the cosmological properties of the rotating sources ; and ( 5 ) the relationship between the quantum chemical theory and the qcd red s functions is
the decoherence phenomenon has been widely discussed and accepted as the mechanism responsible for the emergence of familiar classical features in the real physical world.   the recent experimental observation of diffraction and interference patterns for large molecules like @xmath0, which are expected to behave like classical particles @xcite, raises a natural question : how far can one go before Decoherence effects destroy the interference pattern of massive objects?   we have studied the effect of decoherent on the observed interference pattern in a double - slit experiment in a simplified way. using the markovian master equations with some approximations, we have shown that the interfering particle can be decohered over a time scale which goes inversely as the square of the separation between the two parts of the superposition@xcite. by taking into account the distance the particle travels from the slit to the screen  , we show that it is possible to explain the observed interplay between the strength ofdecoherence, the slit separation and the distance travelled by the particle.
a simple set of rules, referred to as language or naming games ( ng ), originally proposed in the context of semiotic dynamics, was investigated on fully - connected ( fc ), regular ( mean - field ), and small - world ( sw ) networks.   the original model was constructed to account for the emergence of shared vocabularies or conventions in a community of interacting agents ; however, a simplified version of the ng was recently proposed and studied on various network topologies by baronchelli et al. here   we consider and slightly modify this model, with the aim of studying the spontaneous self - organization process of networked autonomous agents in order to understand how they can reach global agreement without global coordination. using the new model, we show that the convergence process to global agreement is faster on fc networks than on regular networks, but the memory needed to develop the common language is much larger than on the regular networks. when the ng is implemented on watts - strogatz sw networks, the agreement dynamics perform optimally in the sense that the memory requirement is small, while the convergence is much faster than on conventional networks.
soft physics at high energies is of fundamental importance, providing us with new and valuable information about the underlying dynamics of strong interactions.   it is not only the unavoidable fragmentation phase, but also the presence of soft underlying events, originating from multiple parton - parton scattering, which can mask the properties of a hard subprocess. in this review   i discuss three classes of such phenomena : multiparticle production in, diffractive physics at hera and the transition from soft to hard scattering in @xmath1 collisions.
the electric dipole moment ( edm ) of the @xmath2 violation of the rpv sector @xcite is measured experimentally.   the edm is sensitive to the violation of parity and time reversal symmetry, and it is known to have very small standard model prediction@xcite. in this work   we focus on the two - loop level contribution to the fermion edm from the barr - zee type process in the supersymmetric sector @xaite, and we calculate the rainbowlike contribution by replacing the higgsino with the neutrino and the gaugegino with the lepton doublet or singlet left - chiral superfield.    we also analyze the effect of these rainbowlike diagrams by comparing with the experimental edm and the chromo - edm generated by the r pv barr-zee type diagrams.
the generalized chaplygin gas model ( gcgm ) has been widely considered as an alternative to the cosmological constant and to quintessence as the dark energy that drives the present acceleration of the universe. in a previous work, we have analysed the case of this model using the type ia supernovae ( sne ia ) data.   one important aspect of this analysis is the use of the bayesian statistics, for one side, and also the fact that all free parameters ( hubble constant, the curvature term, the value of the sound velocity and the proportion of ordinary matter and chaply gin gas ) of the model were taken into account in the treatment of the problem. in the present work  , we apply the same analysis, using the bayes statistics and taking into account all free variables, to the gcGM.. the results show that the gCgm is the preferred model for the unification of dark matter and dark energy.
the coupling of two phosphorus donors in silicon ( si : p ) to each other is a key step in the development of a quantum computer.   it is now possible to measure the hyperfine coupling to the donor nucleus, and to manipulate an individual p - donor nuclear spin. however, the most straightforward way of coupling two donors together is to place them close enough so that their electronic wave functions overlap, and this results in a coulombic interaction between donors that depends strongly on the electronic density of both donors involved. here  , we use a multi - valley effective mass theory to investigate the effects of the central cell and mass anisotropy present in the si conduction band, and show that the spread of the electronic wavefunction is significantly overestimated by previous treatments, which only rely on fitting of orbital energies. using this approach, we show that there is a significant suppression in the oscillatory nature of the exchange coupling, especially for certain geometries. as a result, we are able to provide a clear physical explanation for our predictions, based on the analytic nature of our treatment, and point out interesting consequences for experimental implementations.
we consider three prototype instabilities generated by external loads in an incompressible isotropic elastic body made out of either an elastomer or a biological soft tissue material. for the purpose of comparison,   we adopt four different strain energy functions which are popular in literature on elastomers and on soft tissues namely, the mooney - rivlin model, the fung models, the gent model, and the one - term ogden model.   these functions are used to model the effects of external loads on the stability of a half - space made of soft tissues under compression, whereas half - spaces made ofElastomers always possess a critical stretch beyond which surface instabilities develop.. similar conclusions are drawn for inflation instabilities of spherical membrane shells.
@xmath0 mesons are of special interest in the study of strongly interacting hadronic matter under extreme conditions.   recently, new experimental data from cern - sps on @x Math0 meson production in central pb+pb collisions at 158gev / a beam energy became available.. the purpose of this paper is to show, that the @x math5 meson formation spectra reconstructed via the dileptonic decay channels @x maths2 and @x mathematics1 can be significantly different up to the level of present experimental observations.    we derive in section  iii expressions for momentum distributions of @x mathematician 0 mesons detected via the dilemma - decay channels@xmath8 and @Xmath9 channels. after taking into account rescattering of decay kaons and in - medium modification of @ xmath0 Meson properties, the results are presented in sections  v and vi.
in this paper, we describe a new framework that enables image systems engineers to rapidly design image processing pipelines that are optimized for novel camera architectures.   the framework is called @xmath0 and consists of two main steps : rendering and learning. in the rendering step,   an adaptively selects from a stored table of affine transforms to convert the raw camera sensor data into an image in the target color space ( e.g. srgb ). in training step, the system joint optimization and data - driven learning methods are used to learn the transformations used in rendering. using the example of a camera sensor with rgbw ( red, green, blue and white ) color filter array, we demonstrate the performance of @x math0 method by comparing the rendered quality with the ones from high - end modern digital cameras. as a result, we show that the @x maths0 method accurately approximates the complex, nonlinear pipelines implemented in modern consumer photography systems. in addition, we illustrate how @x Math0 method can learn image processing algorithms for new camera architectures through simulation and learning methods.
in this paper we introduce a novel generalization of derivatives of both riemann  liouville and caputo types and show the effect of using it in equations of mathematical physics or related to probability.   the so - called hilfer fractional derivative interpolates the prabhakar derivative, first introduced in @xcite, and its caputo - like regularized counterpart. in order to do so, we start from the definition of generalized fractional derivatives given by r.  hilfershilfer and then study some of its properties and, in particular, some related applications of interest in mathematical physics and probability.
natural selection is an egoistic process : individual organisms compete for representation of their genes in the next generation, and only those genomes better able to survive and reproduce are likely to be maintained in the evolutionary process. in this framework   it is difficult to explain how " altruistic " genes ( that is genes which determine a behaviour disadvantageous to the carrier, but beneficial for other individuals ) can be selected.   nevertheless, we can find in nature some examples of altruistic behaviour : social organization in insect societies, parental care, warning calls in birds, and so on. so far, there is no evidence of a genetical basis for altruistic behavior. however, it is an interesting problem in itself to understand how interactions between individuals may be reflected on the action of individual natural selection. here   we show in an exactly solvable model, that altruistic behaviors can be chosen both disregarding relatedness between individuals and maintaining the individual as the selection unit : morevoer, that, if the advantage of the presence of altruistically behaving individuals is already felt when their number is small, the stable situation is one in which inhomogeneous groups, formed of both egoistic and altruistic individuals, coexist with both fully
the problem of within - network classification in partial labeled networks has attracted much attention recently.   the problem is to predict the labels of unlabeled nodes based on the known labels and the network structure. here  , we compare the performances of even - step random walk with restart ( rwr ) index with other nine similarity indices which have been widely used in link prediction problem @xcite. these include five local indices, namely the _ common neighbors, _ jaccard coefficient, _ srensen index, _ adamic - adar index,   _ katz index,_ average commute time, _ cosine based on pseudoinverse of the laplacian matrix, and   random walking with restart index.    empirical results on the co - purchase network of political books show that the similarity - based methods perform better than the relational neighbors algorithm, especially when the labeled nodes are sparse. furthermore, when the data is dense, the local indices perform as good as the global indices, while when the information is spare the global ones perform better.
the voronoi diagram of a finite point set partitions the space in cells according to proximity relations induced by a distance function @xmath1.   the structures of vor onoi diagrams appear in various fields such as crystallography, astronomy and biology. in this paper, we focus on characterizing and building efficiently the hyperbolic vorontoi diagram in klein projective disk model. using the graphics processor unit ( gpu ), we present an image browsing application in the hyperBolic disk model that requires two basic user interface selection operations that are solved by means of nearest neighbor queries and by finding the smallest enclosing ball inhyperbolic geometry.
superconducting ( sc ) superconductivity in the electron - doped cuprates @xmath5ce@xmath1cuo@xMath2 ( ncco ) is a consequence of a fermi surface reconstruction by a long - range commensurate antiferromagnetic ( af ) potential in the underdoped regime, which survives up to the optimal sc doping level.   however, the exact nature of the underlying non - superconducting state is still controversial. here  , we report systematic high - field magnetotransport studies on high - quality nCCo crystals, which allow us to precisely locate two critical doping levels in the normal - state phase diagram of this material and correlate them with the position of the sc dome. using a quantitative analysis of the shubnikov - de haas ( sdh ) quantum oscillations observed in the magnetic - breakdown ( mb ) regime on overdoped samples, we evaluate the small mb gap separating the hole and electron pockets of the reconstructed ferm i surface, as a function of the crystal doping level, and find a small dependence of the gap on the sc critical temperature, both extrapolating to zero at the same characteristic doping
a very intriguing feature of above - threshold ionization or high - order harmonic generation is the dependence of these phenomena on the intensity of the driving - field intensity.   the photo - electron peaks in the spectrum @xcite present resonance - like enhancements, such that a variation of a few percent in the external - field strength may drive up the spectral intensity by an order of magnitude. here  , we discuss the possible mechanism of these enhancements, which are related to the existence of rydberg states that, for an appropriate ponderomotive upshift, become multiphoton resonant with the ground state.
we propose a theoretical framework for describing the hysteretic behavior of fluids in disordered porous solids@xcite.   we study the scaling behavior of the adsorption isotherms in the vicinity of the disorder - induced critical points in the temperature - porosity diagram and present new results concerning the statistical properties of the avalanche properties as a function of temperature and porosity. by characterizing the avalanches geometrically and studying their possible relation with the aerogel structure  , we show that the size of the scaleable avalanches depends on the temperature and the porosity of the system. at very low temperature,   the largest scaleable avalanche is observed at @xmath5 in a porosity silica aerogels ; at increasing porosity, the size decreases to @x Math1.. the size increases again at higher porosity but does not reach equilibrium at any temperature above @x math2. at all other temperatures, the slope of the slope decreases from @x maths1 to @Xmath2.    this is in agreement with our theoretical description which predicts the change from a continuous to a discontinuous adsorbed fluid as one decreases the temperature ( at constant
we investigate the effects of site and bond disorder on the spin correlations of site- and bond - diluted spin-1/2 af heisenberg ladders with n=2, 4 and 6 legs.   we find that for site - diluted even - leg ladders, the system is driven to a gapless phase with short - range correlations upon doping up to @xmath12 legs, which are then suppressed by a low level of dilution. in the case of bond - Diluted ladders ( n=4 or 6 legs ),   the correlation length becomes logarithmically divergent for vanishing temperatures only beyond a critical dilution, and the system realizes the physics of the random - exchange heisenburg model with a discrete distribution of the effective couplings, leading to a non - universal behavior at low temperatures.
we have recently introduced a nonlocal monte carlo ( mc ) scheme for the generation of uncorrelated configurations of particles in simulations of hard - sphere fluids.   the method is based on the swendsen   wang ( sw ) algorithm for ising and potts models, which is well known for its ability to identify clusters of particles that are constructed in such a way that all proposed moves are accepted. here  , we show that this generalization can also be applied to off - lattice fluids, in which identical particles do not interact and, unlike species, do not experience a hard - core repulsion. using the generalized ( generalized ) _ geometric cluster algorithm _ ( gca ), we find that the probability of transforming an overlap - free configuration into a configuration with a different boltzmann factor is proportional to the ratio of the two factors of the original configuration and the new configuration. by applying this principle to the hard - spheres of the stillinger  helfand model,   we demonstrate that the gca can be extended to other systems, including the widom  rowlinson model for fluid mixtures and the closely - related stillinger / stillinger model for soft -
the convergence of space - time fluctuations of two - point functions to the squared field of the ornstein - uhlenbeck process is considered in the theory of regularity structures.   this field was first considered in @xcite, where it was explicitly stated as a part of a program towards the derivation of the kpz equation from general stochastic lattice models. in this paper   we propose a new, different approach in order to define the field @xmath3. for the stationary situation, on which for any fixed time @x Math4 is a spatial white noise of variance, one can take an approximation of the identity @x math7 centered at @xMath8, and consider @x maths3 as the limit of@xmath9. the results show that this plan is not always applicable to the case of the black - and - white noise solution of thekpz problem.
we propose a new theory of general relativity based on the conservation group of coordinate transformations.   we look for the largest group of transformations for which the wave equation, @xmath5, is covariant and this is the guiding principle for our theory. in order to model dark matter cosmic acceleration, we require that quantum observers be on equal footing under the conservative group property. by taking the manifold view, we see the neighborhoods upon which the coordinate systems of the second observer make sense to us as the first observer has shrunk from global to local ( special relativity ) to infinitesimal ( conservation group theory ).
the red giant branch ( rgb ) is the major source of interstellar dust in globular clusters ( gcs ).   its mass loss is of critical importance to the later stages of stellar evolution, but the amount of mass loss that occurs on the rgb remains largely unmeasured. here  , we investigate the role of metallicity in this process by comparing the spectra of the galactic globular cluster 47 tucanae ( ngc 104 ) with those of two other gcs, @xmath0 centauri and @xcite, and show that the latter has a much larger mass loss than the former. using a combination of density and temperature measurements, we find that the diameter of the rgb tip is significantly larger than that of the asymptotic giant branch from ngc 362, suggesting that the rgb is an important source of dust production. however, it is not known whether the rgb stars can form significant amounts of dust in their ejecta. if so, it would add a large number of dust factories ejecting dust into a galaxy s interstellar medium ( ism ) ; e.g. the missing dust source in many galaxies. instead, our results suggest that the bulk of the
depletion interactions play a central role in the current understanding of the phase behaviour of dispersions containing colloids of different size and/or shape.   depletion interactions are often treated as true, instantaneous potentials even when considering time - dependent phenomena such as the kinetics of demixing and gelation @xcite. here   we show by means of scaling theory and brownian dynamics simulations that the static depletion interaction potential is only approached algebraically in time. this must have an impact upon processes such as phase - separation kinetics and gelated phases.
in this paper, i examine the notion of actual causation in the context of probabilistic logic programming language cp - logic.   i first explain the differences between structural models and cp-logic, and offer some hand - waving arguments for why cp - Logic might offer a more appropriate setting for the study of real causation than structural models. then, i give my own account of the hp definition of actually causation, which attempts to capture the intuition of pearl s ( 2007 ) work on the issue of actual causality in the framework of structural models using structural models as a representation of causal relations. finally, i briefly comment on a naive implementation in prolog that can be downloaded to play with my definitions.
we re - derive a former heuristic gravity - related decoherence model.   it is based on the assumption that the newton gravitational field possesses a universal uncertainty which is modelled by a zero - mean white - noise with spatial correlation, and that this noise causes a certain universal decoherent between macroscopically different mass distributions. in this paper  , we discuss a possible mathematical model for hybrid composite systems consisting of one quantum and one classical subsystem.
the open cluster ngc  6866 ( @xmath10 ) is a member of the thin - disc component of the milky way galaxy.   it is one of the most well - known open clusters in the kepler field since it is located in the northern sky area of the Milky Way and its metallicity, distance and age are almost at the same as those of the other open clusters. however, the structural and astrophysical parameters of the cluster have to be determined through precise photometric and spectroscopic observations. here  , we use the ccd _ ubvri_ observations of this cluster to derive the cosmological and kinematical parameters for the first time. by fitting stellar isochrones to the observed colour - magnitude diagrams ( cmds ), we find the redshift from the stars with high membership probabilities and then keeping these two constant, we derive its distance modulus and age by fitting star - to - star distances and ages by fitting the observed cmds to the nearest near - infrared ( nir ) band. using the nir band, we also find the radial velocities of two giant stars in the cluster field and derive the proper motion components as @
the idea of space - time coding for cooperative wireless relay networks has been applied in a recent work @xcite.   the differential encoding / decoding setup introduced by kiran _   et al. ( jing - hassibi, jing and jafarkhani, 2012 ) for cooperative communication using cooperative strategies has been generalized to allow the use of codebooks consisting of scaled unitary matrices which are more general than those used in the setup proposed in @xmathite. in this paper   we present a generalization of the differential encode / decode setup introduced in @xcitesite for wireless relays that use codebook consisting of unitary Matrices to allow them to be used in a distributed manner as distributed differential spaces - time codes ( ddstcs ). except for the alamouti code  , all other ddstc constructions in the literature have large decoding complexity. here, we address this issue and present the following contributions : ( 1 ) the notion of encoding complexity for space -time codes in terms of @x Math8-group encodability is introduced ( definition  ) and its significance is highlighted.    ( 2 ) the
azobenzene - functionalized self - assembled monolayers ( sams ) on metal surfaces represent a viable and efficient way to obtain ordered architectures of photo - switching molecules.   @xcite however, it has been observed that in such closely packed systems photo - isomerization can be drastically hindered by steric effects, @xmath1-self - consistent - field ( @x Math1scf ) and even by excitonic coupling between the chromophores. to tune these complex systems in view of optimized performance, a deep knowledge of their chemical composition and structure - property relationship is required. here  , we present an _ ab initio  study of x - ray absorption spectroscopy ( xas ) from the nitrogen ( n )@xmath0 edge of an azobenzenes -functionalized sam of alkanethiols on gold, using density - functional theory calculations. at increasing density of azobenzenes,   the xas are more strongly affected by the nature of the excitons and the binding energy of the core - level excitations, i.e., the transitions from 1@x math2 electrons to the conduction bands.
the production of nonclassical radiation and novel measurement devices have become more and more important to test and apply the quantum phenomena of light.   hence, a careful measurement analysis is required to distinguish classical correlations from those arising from quantum physics. in this article  , we aim to describe a general measurement scenario where multiple detector systems are used to detect nonclassically correlated light beams. for this purpose, we consider higher order moments of the click - scounting statistics ( e.g., the mean value and the variance ) and derive a matrix of moment criterion for the identification of non classical correlations between the emitted light beams that are solely based on the measured statistics itself. using this criterion,   we find that the detectors can be described by a quantum version of a binomial statistics with a principal minors of the matrix of moments which yield a range of applicable conditions.
the complex sine - gordon model is a two dimensional integrable generalisation of the sine-gordon theory.   it has been used in the literature to describe a number of different types of non - perturbative field theories, from general relativity to the description of optical pulses in a non - linear medium. in this paper   we study the csg model in the presence of a boundary for the first time and find that it is well suited to be studied on the half - line. by explicitly abelianising the lax pair description of the model and ensuring that the charge of the solitons and breathers are conserved on thehalf - line  , we show that the boundary conditions introduced by ghoshal and zamolodchikov @xcite can be used to study the nature of the solution in the bulk.
we present an analytical solution to a three - qubit dicke model.   we extend the previous generalized rotating - wave approximation ( grwa ) in the one - qu bit rabi model to the three- and more - qubits dicoke model. including the counter - rotating - waves ( crw ) interactions, we derive a solvable hamiltonian with the same form as the ordinary rwa term. using the zeroth- and first - order approximation, we give an analytical expression of eigenvalues and eigenstates of the three - qbqdicke state for the two parties of the multipartite entanglement. by combining the crw interactions with the grwa  , we show that the ground state is simply a direct product of the low state of the qubit and the vacuum cavity. under the rwa,   the crW interactions lead to a squeezed vacuum state containing virtual photons which are then directly related to the ground states of the quantum information qubits.
the oxidation of magnesium oxide ( mg(0001 ) by oxygen is a process of dissociative chemisorption of oxygen on a clean surface followed by the formation of a film of metal oxide.   the structure of the initial phases of the oxidation process has been extensively studied by experimental and theoretical studies. in this paper   we present a systematic study of the first - principles theory calculations of the oxygen incorporation and island formation at low o@xmath1 exposures in the early stages of mg oxidation using high - quality x - ray photo - electron diffraction ( xpd ) measurements for very low doses of oxygen. based on the calculations,   it is shown that the initial oxygen incorporation occurs in the octahedral interstitial sites of the top - most subsurface ( tetrahedral ) spacings of mg atoms and is followed by islands and lateral growth of incorporated oxygen atoms into islands which are then assembled into a monolayer of epitaxial oxide with a thickness of about 0.51 monolayers or more depending on the coverage of the surface. from the results of the calculations we propose a four - stage model of the oxidized mg surface consisting of : ( 1 ) dissociation of oxygen
digital fingerprinting is a technique that assigns to each user a mark in a way that enables the distributor to identify at least one of the members of the coalition as long as its size does not exceed a certain threshold @xmath5, which is a parameter of the problem.   we are interested in computing the fundamental limits of the fingerprinting problem, i.e., in establishing bounds on the capacity ( or maximum attainable rate ) of fingerprinting codes. for any single deterministic code,   the probability of decoding error in the " wide - sense " formulation ( see section  ) is bounded away from zero and hence the distributor needs to use some form of randomization, where the random key is known only to the distributor, in order to construct such fingerprinting coding codes. here  , we present a new method for determining the limit of the capacity of fingerprints against coalitions of size @x Math5 by comparing the number of fingerprints detected by the coalition with the total number of fingerprinted copies distributed to all the users of the system. using this method, we find that the maximum achievable rate of detecting and modifying the fingerprints of the coalitions can be found to be
in this article we present a refined version of karr s summation theory, which leads to the definition of the so called depth - optimal @xmath3-extensions.   various important properties hold in such extensions which are relevant in symbolic summation.. moreover, an efficient telescoping algorithm which computes sum representations with optimal nested depth is presented. as a measure of simplification   we introduce the notion of nested depth. and the main part of this article deals with the problem of finding sum representations which are optimal with respect to this property.
the proximity effect in superconductor / ferromagnet ( f / s / f ) trilayers with atomic thickness has recently been probed with various experimental techniques.   it was established long ago that the superconducting transition temperature is larger in the antiparallel alignment because of the exchange field induced in the s layer   @xcite that tends to dissociate cooper pairs. following this theoretical prediction two experiments were performed with metallic ferromagnets and it was shown in both cases that the critical temperature was larger for the ferromagnetic electrodes in the parallel alignment than for the supercond conductor. on the other hand   the zero - temperature super conductance gap is, like with insulators, larger when the ferroelectric electrodes are connected to the superonducting layers.    this suggests that the proximity effect plays a dominant role in the determination of the zero temperature superconductation gap and that pair breaking effects play a dominant roles in the determined critical temperature. in this letter   we determine whether this picture is robust, including realistic ingredients such as a strong or weak exchange field in the ferromaagnets, disorder or a finite thickness in the super Conductor.
the economy is a complex interacting system that responds to a multitude of influences and extends over a wide range of monetary scales.   understanding how an economy develops and how it is influenced by externalities remains poorly understood. in this short review,   we present an interacting many - agent model of the macroeconomy that can be quantitatively analyzed using statistical physics tools. through a large number of asset exchanges between randomly - selected pairs of agents, a global wealth distribution develops, and we want to understand how generic features of this distribution depend on the nature of the exchanges. as a preliminary, we study additive exchange processes, in which a fixed amount of asset is exchanged between two agents, independent of their wealth before a trade occurs. under the condition that bankrupt agents are eliminated from further economic activity, we determine the consequences of : ( i ) _ fair _ transactions, where either agent is equally likely to profit in an interaction, and ( ii )  greedy  transactions, when the richer agent profits more than the less wealthy agent. for each type of interaction, we show that the effective temperature of the wealth distribution is equal to the average amount of wealth per agent, and that the effect of the agent's wealth on the
the frozen coupling constant approach for the calculation of the hadronic wave functions in the perturbative qcd ( pqcd ) coupling @xmath1 is presented.   the main purpose of this work is to investigate the influence of the renormalization scale on the hadron - to - hadron fragmentation functions, which are the underlying links between hadronic phenomena in qcd at large ( nonperturbative ) and small distances ( perturbation ).. the results show that the number of infrared renormalons in the integral of the qcd coupling@xmath2 is reduced by a factor of 1.1 in the soft regions of the quantum chromodynamics ( qcd ) theory, where the energy of the interactions is very low. however, the power - suppressed contributions to the higher - twist contributions to some inclusive processes are still larger than those to the exclusive processes, such as the two - jet+meson production in the electron - positron annihilation, and the meson photoproduction in the proton - proton exchange. from these results,   it is shown that the Hadronic distribution amplitudes and structure functions which enter exclusive and inclusive processes via the factorization the
the rate and amount of mass lost by red giant branch and asymptotic giant branch stars is a major uncertainty in stellar evolutionary theory.   globular clusters ( gcs ) have long been the prime testing grounds for stellar evolution theory. here   we present results of a survey of eight milky way gcs using 24 and 70  @xmath0 m observations with the multiband imaging photometer for _ spitzer_ ( mips ; *????)we find evidence for an infrared ( ir ) excess in several of the target clusters and upper limits on the remaining clusters, suggesting that the mass of the intra - cluster medium ( icm ) is likely to be much lower than expected. from these results, we propose that the observed mass loss rates are consistent with the theoretical prediction that stars more massive than@xmath2 lose a significant fraction of their mass after leaving the main sequence.
we develop a theoretical model for cascaded third harmonic generation in graphene - based plasmonic waveguides.   we show that engineering modal dispersion allows to simultaneously satisfy second harmonic generation ( shg ) and sum - frequency generation ( sfg ) phase - matching, and offers 5 times increase of third harmonic output compared to direct non - cascaded thg.
we propose a scheme for the generation of fock states in a traveling mode.   the scheme is based on an avalanche triggering photodetector and a ring cavity coupled to an external traveling wave through a cross - kerr medium, which is fed by a coherent state in the cavity, whereas the mode is left unexcited. at the output of the cavity the field is monitored by an avalanche photodenverteector, which detects the presence or absence of the field, and then triggers the synthesis of a fock state using a simple on  off detection of an intense coherent field. as we will see, the scheme can also be used to engineer superpositions of few fock ( number ) states, which are crucial for optical quantum computers and quantum tomography of optical hamiltonians.
the theory of dark energy dominates the modern cosmology in the past decade.   the recent observations of riess and perlmutter on distant supernovae indicate that the universe is expanding and the luminosity distance can not be explained by a matter dominated universe. to explain the observed observations,   several modified theories of general relativity have been developed as the alternative source of cosmological acceleration. in this letter  , we present a new model of navigation cosmolgical model based on finsler geometry which could explain the recent astronomical observations which einstein s gravity could not. for this purpose, we propose a novel form of riemann geometry - finsler geometrical model. instead of defining an inner product structure over the tangent bundle in rieman geometry, finsler geometric model is based on the so called finsler structure @xmath3 with the property @x math4 for all.. the influence of a possible drift ( wind ) in the navigation cos molgical models makes the expanding universe  accelerated ".    it is remarkable that the navigation Cosmological model is described in the framework of finsler Geometries. here, we find that the predictions of
when the same concept admits more than one lexicalization, it is often difficult to choose which of these ` synonyms'is the most appropriate for achieving the desired pragmatic goals.   knowledge - based approaches to representing the potentially subtle differences between synonyms have suffered from a serious lexical acquisition bottleneck @xcite. statistical approaches, which have sought to explicitly represent differences between pairs of synonyms with respect to their occurrence with other specific words, are inefficient in time and space. here  , we present a new statistical approach to modeling context that provides a preliminary solution to an important sub - problem, that of determining the near - synonym that is _ most typical _, or expected, if any, in a given context. using a generalization of lexical co - occurrence, we show that even though a word might not co - occur significantly with another given word, it might nevertheless be able to predict the use of that word if the two words are mutually related to a third word.see research article http://www.biomedcentral.com/1741-7007/1471-2148/9/8/10
low mass stars ( lms ) are important probes of main sequence stellar evolution and are key in determining the boundary between stellar and sub stellar objects.   however, their spectra are extremely rich in structure and their opacity is made up of many molecular and atomic absorbers, each with hundred of thousands to millions of spectral lines. here   we propose a new methodology for establishing the effective temperatures of cool stars, in particular lms, based on high resolution mid infrared ( mir ) spectroscopy. using this method we show that the effective temperature of lms can be determined by estimating the strength of individual rotational water lines in the mid infrared region at energies above 20000 @xmath3 m. these lines are largely pure rotational, in contrast to the vibrational and rotational motion of asymmetric triatomic molecules found in the near infrared ( nir ) where they are dominated by vibration - rotation transitions. as a result   the analysis of the mir spectra of sunspots provides a large dynamic range for temperature analysis which is characteristic of the sunspot spectrum and could make the mir region ideal for the determination of the effective heat scale for lms.
we present a detailed multiwavelength study of psr  j1048 + 2339, a redback radio pulsar found in a fermi - unidentified source by @xcite.   the pulsar was discovered in a radio search at 327  mhz with the arecibo telescope of high - latitude _ fermI  unidentified sources from a preliminary version of the 3fgl  j 1048.6 + 2338 source catalog. using two years of radio timing observations and polarimetry, we show that the system is a millisecond pulsar ( msp ) with a pulse period of 4.66 ms and a dispersion measure of 16.65  pc  @xmath4. during the last two years  , we have observed the radial rotation of the pulsars companion at 14.5  kpc and 1.2  kph, respectively.    in addition, we performed polarimetric measurements of the gamma - ray spectrum of the black widow pulsar psr j1048+2339 using the large area telescope ( lat ) on the same day of the first observation. while the band gap between the two observations was larger than the receiver bandwidth
the capital asset pricing model ( capm ) is based on variance as the measure of risk.   however, it has been clear from the outset that this way of measuring risk has a serious drawback : it penalizes high profits in exactly the same way as high losses. in 1997, artzner, delbaen, eber, and heath introduced the concept of a _ coherent risk measure_. in our opinion, these measures of risk are definitely wiser than the standard ones, i.e. variance and v@r. here   we review the current state of the art in the field of coherent risk measures.
the yukawa light - cone hamiltonian is a well - known model for ( 3 + 1)-dimensional supersymmetric yang   mills theory in quantum chromodynamics.   it has been used to compute wave functions and spectra for the first time in the context of discretized light - cones quantization ( dlcq ). here   we discuss two new approaches to its numerical solution using pauli  villars regularization and supersymmetry, both of which are based on the use of the discreteized light- cone quantization technique.. the former uses three heavy scalars, two of which have negative norm, and the latter uses one heavy scalar and one heavy fermion, both with negative norm. by discretizing the supercharge @xmath0 and constructing a discrete light -cone energy @x math1 from the superalgebra, one can retain supersymmetries in the discrete approximation, now called sdlcq  . the second approach uses a single - fermions truncation of the yukava theory in order to include pv particles in the dlcqs basis. as a result,   the y
the existence of periodicities in stellar variability was well established by the beginning of the 19th century.   it was soon obvious to observers of mira variables and other bright red variable stars that their light curves did not repeat perfectly from cycle to cycle. to account for at least some of these differences, some early researchers attempted to apply additional periodic terms to the ephemeris, implying that the periods of such stars were themselves variable in a periodic way. however, the observed period changes of these stars did not follow these ephmerides. in this paper   we review what is known of the period change of three types of variable star : mira variations, rr lyrae stars, and type ii cepheids. because of the long periods of time during which the variables have been observed, it is important to compare the period changes intrinsic to the behavior of the star to the time interval during which significant changes in period would be expected according to our current understanding of stellar evolution.
the babylonian mathematical astronomy, which was fully developed around 300 b.c.  , enabled the scribes to calculate positions and times of special phenomena. in case of the moon, these were eclipses and some ocurrences around conjunction ( new moon ) and opposition ( full moon ). for the moon they recorded times and positions of consecutive conjunctions or oppositions, labeled by the names of the months during which they occurred. at least since o. neugebauer@xcite we know how the ephemerides were calculated ; but we have still rather little knowledge about how this theory was derived from observations. in this article   we give a short account of our present understanding, making use of modern computer simulations of the lunar data, of some of the methods by which the babylonians arrived at their precise knowledge of the periods of the sun and the moon.
the centre de donnes astronomiques de strasbourg ( cds ) defines, develops, and maintains services to help astronomers find the information they need from the very rapidly increasing wealth of astronomical information, and particularly of on - line information.   simbad is a database of identifications, aliases and names of astronomical objects : in principle any name found in the literature can be submitted to simbad in order to retrieve basic information known for this object, as well as pointers to complementary data and bibliography.database url : http://www.simbad.u - strasbg.fr
we study the effect of non - magnetic vacancies and pairs of vacancies in the kitaev - heisenberg model @xcite on the order and the magnetic response of the antiferromagnetic ( af ) phase of the model, at zero temperature.   we find that the spin liquid phase is a well - defined ground state with a gapless spectrum and low - energy excitations, which is characterized by a gapped vortice and a weakly ordered magnetic moment induced around a spinless vacancy. for the first time, we show that this phase can be used as a probe to investigate the effects of site - mixing effects on the spin - orbit coupling between ir ions on the hexagonal ir - sublattice of the honeycomb lattice of na@xmath3iro@x math4 and li@x Math3iro=0.2 + 0.1 + 1.0 + 2.0 nm, and that it is not only independent of the presence of a magnetic field but also depends on the number of vacancies present in the lattice. from these results, we propose that the existence of a spin liquid ground state is due to an interaction between the two types of vacancies, which
we present hartree - fock calculations for the electronic structure of a model ionic polymer, namely, an infinite lih chain.   the calculations are formulated entirely in terms of wannier functions ( wf ), without using bloch orbitals in any of the intermediate steps. by comparing our results with those of other authors, we demonstrate the applicability of our approach to periodic systems of reduced dimensionality, as well as the ease with which the present approach can be applied to study covalent systems.
the higgs boson is the cornerstone of electroweak symmetry breaking in the standard model ( sm ) and the minimal supersymmetric standard model.   it is excluded from the lep searches for @xmath3 if its mass is lighter than approximately @x Math4  gev / c@xmath5@xcite.. the production rate of the sm higgs plus one jet process has been calculated exactly at next - to - leading order ( nlo ) in the heavy quark effective theory ( hqet ) with the inclusion of top and bottom quark loops. here   we present the calculation of the same process at nlo for the lightest scalar and pseudoscalar higgsbosons of the mssm, where the top quark mass is assumed to be much heavier than the higgs Boson mass. by combining the results obtained in the h qcd @xcite with the calculations for the other two models, we show that the difference in the total cross - section for the low order process is due to the presence of a large number of loops with bottom quarks, which are important for the detection of the highest order process.
antiferromagnetically ordered ( afm ) compounds with a layered tetragonal structure type, which have over 600 intermetallic members, crystallize in the variant with structure @xcite.   the structure type has recently been found to be a suitable host for exotic physical properties, such as the occurrence of structure - driven quantum critical points at @xmath6-@xmath7 phase transitions, e.g., or the heavy - fermionic superconductivity in @xcites. here  , we present the magnetic properties of, a compound we find to be an a - type antiferromagnetic, which displays metamagnetic field - induced transitions initiated in external magnetic fields even below @x Math10 t. the magnetization of the compound was studied using a _ quantum design _ magnetic properties measurements system ( mpms ) xl 7 t with a differential superconducting quantum interference device ( squid ) equipped with a reciprocating sample option ( rso).the measurements were performed in a temperature range from @x math13 = 5 to 300 k and in fields between @x maths14 = 0 t and 7 t. it was found that the compound exhibits a non - collinear
we study the time evolution of a pair of spinons in a two - leg spin ladder model, and find that the confinement mechanism would lead to nontrivial dynamics of the spinons, which enables us to visualize the confinement directly through the non - equilibrium dynamics in real time.   we reexamine the confinement phenomenon of quarks in quasi-1d strongly correlated systems such as spin ladders with ising - like exchange anisotropy using the adaptive t - dmrg@xmath6/t - dmsr model. for a single spin chain,   no confinement occurs because a pair can be separated as far from each other as possible without costing energy. for both legs of the ladder system, however, the distance between the spinon couplings is linearly increasing with the mismatch length. in the case of a strongly coupled ladder system where the coupling is antiferromagnetic and the ground state is ferromagnetic, the interaction between the two spinons increases linearly with distance due to the mechanism of confinement arising from the @xmath2 color gauge theory. by taking advantage of the experimental observation of a confined - deconfined crossover in neutron scattering experiments for a weakly
in this paper, we propose a generalised model of blind interference alignment ( bia ) in a heterogeneous network, where there is one macrocell with @xmath0 users and @x Math0 femtocells with one user each.   the proposed scheme is based on the construction given by jafar, , in the case @x math4, introducing the application of bia to heterogeneous networks, and introducing a new description of the bia model using a kronecker product representation for the signal - to - noise ratio ( snr ).    based on our findings, the dof that can be achieved in both tiers of the network are presented, and the achievable sum rate formula for the heterogenous network is introduced.. finally, we discuss how to vary parameters of the model to maximize sum rate, extending the ideas of -, and demonstrating optimality in the sum rate sense.
the crab is the first source of gamma rays to be detected by ground based telescopes @xcite and measurements of its emission spectrum between @xmath8 and@xmath9 by various atmospheric erenkov detectors are now available. at these energies emission from the crab is steady and generally accepted to come from the nebula, arising from the inverse compton scattering of the synchrotron photons observed at lower energies.   we present the first measurement of the flux from the Crab above @x Math28, as well as an upper limit for the flux measured by the stacee experiment using the mirrors of a solar energy research facility in the french pyrenees ( celeste ). with a total mirror area of > 40 mirrors, the crab has a flux of ~200 gev, which is below the threshold of the minimum energy threshold for current ground based imaging experiments. while the origin of the pulsed emission is uncertain, it is thought to originate from the red - shifted proton emissions from the cluster of supernovae that surround the crab.
the large hadron collider ( lhc ) is currently investigating the nature of electroweak symmetry breaking.   a recent breakthrough was the discovery of a higgs candidate, @xcite, which is an elegant candidate for supersymmetry ( susy ). in this paper   we extend upon previous studies of sneutrino supersymmetric particle ( lsp ) decays in bilinear r - parity violation ( brpv ) into " non - conventional " modes : pairs of heavy standard model ( sm ) states, invisible modes and different - flavor charged lepton final states. by studying the effect of neutrino masses on the decay of the lsp in these modes, we show that they can dominate sneutrin decays and can yield unique and unanticipated susy signals. specifically, when the lepton doublets are mixed with the up - type higgs doublet in the superpotential, the same lepton number violating terms are also present in the sm state and the invisible mode but the mixings are not in the final state. furthermore, the neutral lsp decays are dominated by the dark matter - like couplings between the leptons and the gravitinos
we study in detail the process of ultraslow scaled brownian motion ( usbm ) with time dependent diffusion coefficient in free cooling granular gases with constant, sub - unity restitution coefficient in the homogeneous cooling state.   we present analytical and numerical results for the mean squared displacement ( msd ) and the time averaged msd for the cases of unconfined ( section  ) and confined ( sections  and  ) Brownian motion of particles in a three - dimensional force - free granular gas with constant restitution coefficient. at short times   the particles follow ballistic trajectories, while for longer times the ensemble average msd has a logarithmic time dependence. by using the langevin equation for usbm and a summary of the simulations procedure we show that the self diffusion of the particles in the two - dimensional system is governed by an ultraslow scaling of the msd of the form (  ) with a component decaying inverse - proportionally with time, which is found to be the case of the kinetic temperature of the gas particles. on the other hand, the entropy of the particle - particle collisions is not affected by the
baryons in ads / cft was first introduced by witten in @xcite, where baryon is identified with a compact d - brane wrapping the directions transverse to the @xmath0 color d-branes with strings attached to it.   the issue is then whether there is a beryon vertex for the given gravity background and given probe branes. here   we examine this issue in various gravity backgrounds with the probe probe brags using the equation of motion and force balancing condition ( fbc ).    we find that there exist baryone vertex ( bv ) only in some of the confining backgrounds, while no such object in any of the black hole backgrounds.. in case there are baryons, interesting question is the density dependence of the barieson mass in the absence of lorentz symmetry. in the present paper, we show numerically that mass drops as density increases for baryones with heavy quarks, while mass v.s density profile has a minimum for bryons with light quarks.
we plan a long - term monitoring observation of the famous microquasar ss  433 with rxte. in the plan,   a radio flare is triggered with the ratan-600 radio telescope, which indicates that the source enters its high state.   the source is observed for 3 ks everyday until 2001/11/25. during this period, the source has been in the quiescent state and the massive jet blob has been ejected from the system. to observe the ejection of a massive jet blob, we have monitored the source with the too monitoring observations of ss 433 with r x - ray teflon spectroscopy using layer  1,  2, and  3 of the photcolysis calorimetry ( pca ) at the level of the standard-2 phase of the plasmodium-1,2-catalyzed proton array ( psa ).. the results show that the continuous jet flow of the jet blob was as long as @xmath7 cm2, and the cooling time of the x -ray emitting plasma as short as@xmath8 s. the fast variation clearly seen in the raw count rate of
the current successes of cold dark matter cosmologies, and in particular the @xmath1cdm models, are well known.   these models follow the evolution of dark matter, and the accompanying galaxies are assumed to form as gas flows into the ever growing dark matter condensations. however, there are some well known difficulties with these models in that they predict too many faint and too many bright galaxies, and they predict that the largest galaxies should be blue and star forming. to address this problem,   one of the most commonly used assumptions in semi - analytic models is that of " feedback " from the central regions of the galaxy, where energy in some form is produced in sufficient quantity that it can heat the inflowing gas, perhaps stopping or reversing the inflow, and then provide enough energy to suppress star formation. here   we show that radio galactic nuclei ( agns ) are viable candidates for powering feedback and for suppressing star formation in massive galaxies using a variety of mechanisms, including radiatively driven winds, agn driven shocks and mass outflows, radio sources associated with agns, and radio - loud agn ( or " radio agn " ) generated by collimated emission doppler
the detection of the relic gravitational waves ( rgws ) in the cosmic microwave background ( cmb ) radiation anisotropy power spectra is a basic prediction in the modern cosmology, which depends only on the validity of general relativity and quantum mechanics.   recently, planck team released their cmb tt data, and shown some differences in the low multipoles compared with the wmap data @xcite. in this paper, we analyze the new data using the public cosmomc numerical package, and investigate the hint of rgws in these new data by comparing the signals generated by the gravitational waves with those of density perturbations in the cmb temperature and polarization anisotropies at low multipole level. as anticipated, we found that the new datasets favor the gravitational wave signals with the tensor - to - scalar ratio of ~1.0 for the tt and ~2.5 for the te, and that the blue tilted spectrum of densities with the constant or a running spectral index is consistent with the presence of rgw signals.
molecular dynamics simulations on large computers have become one of the mainstays for investigating the functions of biomolecules. using statistical algorithms,   they create a large number of snapshots of the molecule that approximate the expected distribution of molecular shapes in actual molecular processes. by looking for typical shapes ( conformations ) and transition paths in these snapshots, biochemists can learn about the molecular bases of biochemical processes.   identifying typical shapes in such a large data set is itself a difficult task. here   we present here two procedures to aid in this task : a projection method to visualize the molecular configurations of a trajectory as a point set in the plane, and a cluster analysis to identify clusters of similar configurations in the trajectory.
we derive the expressions of the neutrino mean free path ( mfp ) and emissivity of the non - degenerate neutrinos in the core of neutron star composed of quark matter using the modified dispersion relation.   the results show significant improvement of the previous results @xcite which is due to the inclusion of magnetic interaction in the relativistic fermi liquid theory.
we present a geometrical framework for the study of conformally invariant fields in conformally flat spaces in four dimensions.   it is based on the " six cone formalism " which sets the conditions, mainly the homogeneity of the fields on @xmath7, to obtain conformal minkowskian fields under the linear conformal group so@xmath5 and extends the formalism to a class of conformably flat spaces which contains in particular two - point functions in the de  sitter group. using this framework, we show that the maxwell equations on a conformallyflat space are converted into constrained scalar equations on minkowski space under very moderate assumptions to both the max well equations and the conformal eastwood - singer gauge conditions @xcite on an @x Math4d conformally Flat space. as a proof of this result  , we propose a new fiber bundle in which, broadly speaking, the max wells equations on such a conformationally flat space are transformed into constraints on minkingowski space.
in the smart - dust paradigm, consider a distributed field sampling problem where sensors are deployed without precise control on the sensor - locations.   this work presents the estimation of a bandlimited field from i.e., distributed but unknown samples in an asymptotic setting ( where the number of samples increases to infinity ). using insights from classical order - statistics and useful statistical theory,   a consistent estimate for the spatial field is presented with a distortion ( average mean - squared error ) and a central - limit type weak convergence result.
in quantum theory the inertial properties of a particle are determined by its inertial mass as well as spin.   this paper is devoted to the notion that the spin - rotation coupling is fully relativistic, since it originates from the tendency of intrinsic spin to keep its aspect with respect to a global background inertial frame (  inertia of intrinsicspin " ).  in particular, the intrinsic spin of a slow neutron precesses in a sense opposite to the sense of rotation of the rotating frame, which can be described by the heisenberg equation of motion with the hamiltonian @xmath6. for fermions,   there exists at present only indirect evidence for the existence of such a coupling. here   we discuss the results of an experiment to measure this effect for neutrons.
the magnetic field plays an important role in physical processes occurring at all relevant coronal heights.   indirect methods available at present are mostly based on numerical extrapolations or various types of radio techniques. in this paper   we present a novel seismological method to evaluate the strength of the magnetic field in the outer corona using the so - called streamer waves, which were generated as the aftermath of the coronal mass ejection - streamer interaction event dated on 6 july 2004. by taking these solar wind parameters from a simplified two - dimensional magnetohydrodynamic ( mhd ) model accounting for streamers, current - plasma sheets, and slow - fast winds developed by chen & hu ( 2001 ), the magnetic fields at heliocentric distances of 5 and 10 @xmath0 are evaluated.. the results show that the radial profile of the alfvn speed and that of its magnetic field strength can be deduced given the speed and density of the solar wind plasmas.
one of the main tasks of modern nuclear and high - energy physics is the quest of the quark - gluon plasma ( qgp ), a new state of matter, predicted to exist at high temperatures and densities.   quarks have been proposed in the middle of the sixties as elementary substructure particles of the strongly interacting particles, the so called hadrons, in order to explain the large spectrum of hadrons discovered at this time @xcite. since the interaction between hadrons is mediated by gluons which also can split into virtual quark anti - quark pairs, the hadrons can be considered as quark bags in which the quarks are confined by their interaction with each other. since then  , there has been a great deal of progress in our understanding of the theory of hadron formation and the role of quarks in it.
the high mass x - ray binary ( hmxb ) system consists of an accreting neutron star ( ns ) fed by the surrounding stellar wind of the b type emission line companion wray 977 ( @xmath977 ).   the pulsar of is one of the slowest known pulsars, with a pulse period of ~695s@xmath14700s and a spin reversal between 1993 and 2008. in this paper, we describe the observed variations in the pulse phase average spectrum of the system over the last 13 years.. the pulses are characterized by a pulsar continuum with a power law with fermi - dirac cutoff and a strong variation in the intrinsic parameters throughout the orbit. during the spin reversal, the pulse period has changed from 695s to @x Math16s and then briefly spun - up from @x math16s to #17s. since october 2010  , it has remained relatively constant around @x maths17s but has experienced a peculiar 1ks dip in the luminosity around @Xmath17s, where the pulsations disappeared for one spin cycle during the dip.
image potential states ( ips ) of nio(001 ) ultrathin films have been investigated by 2-electron photoelectron spectroscopy ( 2ppe ). for 2, 3, and 4 ml thickness nio films,   long - living unoccupied features are observed near the vacuum level.   they are characterized as image potential states. for well - ordered nio film of different thicknesses, the dynamics of the ips directly reflect the coupling to unoccupied nio thin film states.
bistable systems are widely used to model the biological processes which exhibit distinct phenotypes under homogeneous conditions.   switching between phenotypes ( stable states ) is facilitated by the stochasticity arising from molecular noise @xcite. in this paper  , we analyze a coupled bistable system that consists of interacting identical bistsable motifs and show that the transition paths of the coupled system are split into multiple ones, a phenomenon called " bifurcation of transition path ". since many properties of the coupling system, such as the transition rates between the steady states, are dependent on the transitionpaths, it is interesting to study whether the transition pathways of a given coupled bismuthable system b ifurcate and how this bIfurcation relates to the coupling of the individual bistability systems and their coupling. in order to address this question, we construct a general formulation of coupled bishable systems using the maier - stein model of the lysis - lysogeny decision @xmath0-phage lysis process and propose a criterion for the bifurrence of transition paths by extending the previous works on the maiers - steins model @xc
the study of'microquasars ', or relativistic jets from x - ray binary systems, is one of the most vigorously pursued fields in observational high - energy astrophysics in recent years.   observations have clearly demonstrated the presence of jets in most classes of x - rays, and furthermore have clearly indicated a strong coupling with the accretion ` state'of the source, whether neutron star or black hole accretor. while some areas of the coupling between accretion flow and jet are still empirically uncertain ( the atoll sources, the intermediate / very high state for black hole candidate systems ), it seems that all xrbs except the high - field x -ray pulsars will, under the right conditions, produce a synchrotron - emitting jet. to address the significance of this jet, energetically and dynamically, for the process of accretion onto compact objects as a whole, it is therefore an important question to examine the relationship between the properties of the jet and the mass accretion rate, @xmath3, which is traditionally estimated from experiments alone, and the existence of a jet in both the neutron star ( ns ) and black hole candidates ( bhcs ).
the warm hot intergalactic medium ( whim ) is the signature of the baryons visible in the far uv and soft x - ray spectra of the bl lac object mrk  421, which is a calibration target for the _ xmm - newton  high resolution spectroscopy.   the most efficient way to detect such gas is through resonant absorption lines from highly ionized metals ( e.g. ovi, ovii, oviii, neix ) in the spectrum of background sources. in this paper   i present strong evidence for an ovii k@xmath1 absorption line at @xmath3 in the spectral data of mrK  421. by combining the results of the analysis of the rgs2 and rgs1 reflection grating spectra collected by the two_ xmm-newton _ x -ray telescopes with the observations of the h1821@x Mathur, mathur, weimberg & chen experiment, it is possible to predict the temperature of the whim in the region of interest ( @x maths18 from 100 to 500, fwhm, or 100 to 800, hew ) at the time of the
the presence of molecular hydrogen ( @xmath3 ) gas is a key element for supporting star formation in galaxies.   however, not much is known about the distribution of this gas in void galaxies. in this study   we searched for molecular gas in five void galaxies and carried out followup h@xmath0 imaging observations of some of the detected galaxies using the healayan faint object spectrograph camera ( hfosc ) which is mounted on the 2 m himalayan chandra telescope ( hchandra ). at the co rest frequency of 115.271204 ghz,   the cold gas masses of the galaxies were estimated to be about 1.5 - 2.5 times larger than those found in nearby star forming systems. from the results of our followup studies, we conclude that the observed molecular gas masses in the voids are comparable to those found with respect to the distributions of neutral hydrogen and/or neutral hydrogen in nearby galaxy populations.
the majorana fermion bound states that must be present near the ends of one - dimensional ( 1d ) topological superconductor wires are under consideration as platforms for topological quantum information processing. in this paper, we study the coupling between majorana states in a single - channel helical nanowire junction where two or more majoranas are coupled on a superconducting electrode.   we find that the tunneling conductance of electron tunneling into a chain of coupled majoranas exhibits a bias - dependent zero - bias anomaly conductance peak due to resonant andreev reflection, with even - odd parity effects in the tunneled conductance.
type ia supernovae ( sn  ia ) have been used as cosmic standard candles for the measurement of cosmologically interesting distances.   the sloan digital sky survey - ii ( sdss - ii ) supernova survey was designed to further improve their reliability as distance indicators by studying events that do not conform to the general homogeneity in their spectra or luminosity, and has identified a number of sn  1991t - like ( hereafter referred to as 91 t ; *???   * ; *????,91 t = 1.0  km  s1 ; p < 0.001 ) and sn  199bg - like subclasses of sn / 1991t-like ( hereafter 91bg - Like ) supernovas.    sn  2002cx ( hereafter 02cx ) was especially peculiar : it showed a hot ( 91t -Like ) spectrum at early times, but it cooled quickly after maximum brightness and its expansion velocities were well below typical for a type ia single - star supernova. here  , we show that this is due to the formation of intermediate - mass elements from the thermonuclear burning of carbon and oxygen at
we investigate how ontological models can be used to reproduce quantum mechanical statistical predictions for a discrete set of preparations of, and measurements upon, a given system.   we start by discussing a method of representing empirical data in matrix form, and then introduce a matrix factorization of this data, equivalent to an ontological model over a finite number of ontic states. in sections   ,  and  we present three factorizations which can describe any such empirical data. in the second half of the paper, section   , we consider the issue of finding ontology models with as few ontic state as possible - a topic with potential application to the classical simulation of quantum systems.    we provide an explicit example of how to find an indeterministic ontologous model which is able to reproduce the predictions of quantum mechanics for a given set of experiments.
the sloan digital sky survey ( sdss ) has uncovered a significant number of ultra - faint dwarf galaxies in the milky way halo.   however, only a small number of new star clusters have been found with heliocentric distances 1750kpc. here   we report the discovery of a new Ultra - faint star cluster, which we designate as kim3, found in the constellation of centaurus. this concentration of stars was detected as part of our ongoing imaging survey with the dark energy camera ( decam ) on the 4 m blanco telescope at cerro tololo in chile and is approximately 1.5 times fainter than the nearest known satellite galaxies. during the observations and data reduction process, including photometry and star / galaxy separation, we found that the star cluster is located in the southern arm of the magellanic stream, within two half - light radii from the adopted center of kim2 and within a radius of @xmath10 from the adoption center of Kim3.    the observed star cluster has a mean age of 3.1 billion years and a mean distance of 2.4 million km. 	 the mass of the cluster is estimated
chiral symmetry restoration is one of the most important properties to understand the low - energy phenomena of qcd in the real world.   this chiral symmetry is expected to be restored in qcd at several extreme conditions such as qcd with a large number of massless quarks, large @xmath0 qcd and qcd under hot and/or dense matter. here  , we investigate the critical behavior of the masses of the bound states of quark and anti - quark directly from qcd using the homogeneous bethe - salpeter ( hbs ) equation in the improved ladder approximation. by solving the schwinger - dyson ( sd ) equation and the hbs equation simultaneously, we find that the mass of the scalar bound state becomes massless at the phase transition point when approached from the broken phase. on the other hand,   the wave functions of the massive bound states are not massless, but become massless as a chiral partner of the pseudoscalarbound state.. these results are consistent with the chiral symmetry restoration observed by the effective field theoretical approach based on the hidden local symmetry model.
the angular power spectrum of the cosmic microwave background ( cmb ) temperature anisotropy depends strongly on the values of most cosmological parameters and on the physical processes in the early universe.   we use the cmb data from the maxima  balloon - borne experiment, maxima-1, to determine constraints on a seven - dimensional space of cosmologic parameters within the class of inflationary adiabatic models. using a maximum likelihood analysis technique  , we find the most likely values of the cosmology parameters by maximizing the likelihood of the data. for each parameter, we set constraints on the amplitude of fluctuations, the fractional densities of baryons, the spectral index of primordial scalar fluctuations, and the optical depth of reionization. with the exception of the total energy density of the universe,   the constraints are consistent with the results of the cobe / dmr experiments.. we also combine our constraints with those from the high - redshift supernovae measurements to set bounds on the fractionally density in a Cosmological constant and pressureless matter at the time of the first black hole. finally, we summarize our results and discuss their implications for
abstractan epithelial tissue is a sheet of cells that acts as a barrier, separating for instance the outside and the inside of a multicellular organism.   its biological function relies in part on the formation of a network of adherens junction belts, connected to the acto - myosin cytoskeleton, where cells adhere to each other and which transmits mechanical information over several cell diameters. here   we show that single cell junction ablation of epithelial cell junctions can be used to measure the initial stress to viscosity ratio ( tensor ) and the initial strain rate after severing ( strain rate ) within an epithelium during metamorphosis using continuous mechanical measurement techniques. by ablating individual cell junications in either of two perpendicular directions, it is possible to measure step by step the anisotropy of the ratio @xmath9 ( where @x Math10 denotes the tissue viscosities ). 	 the stress toviscosity ratios are then used to calculate the initial retraction velocity, which yields the value of the cell junction tension removed by the ablation, up to an unknown prefactor which depends on the dissipation of the stress.
we investigate the expected fractions of core - collapse supernovae ( sne ) whose observed light - curves ( lcs ) are brightened by a collision based on a population synthesis model.   we find that the expected fraction of sn with little or no hydrogen ( sne  iil / iib / ib / ic ) which are in binary systems is about 1% of the total number of sne progenitors and the observed lc brightening is caused by the collision between the sn ejecta and the companion star.    the observed brightening can be explained by the formation of a hole in the sn at a separation of about 6.5  km from the companionstar. for the majority of the predicted fractions,   the early brightening occurs when the observer is within certain viewing angles from which the collision can be observed.
type ia supernovae ( sne ) have been used extensively for the measurement of relative distances to galaxies.   the sandage / saha   type ia sne hst calibration program has recently been launched as part of the _ hst key project on the extragalactic distance scale, in which cepheid - based distance determinations have been made for 18 galaxies, including one local, calibrating, type iala sne - host. here  , we present a recalibration of the existing data for all galaxies observed with_hst that are host to these galaxies. using the newly developed @xmath7-band hubble diagram, we find that the mean absolute magnitudes of the observed peak luminosities of the four types ia sn from the center for astrophysics ( cfa ) survey at redshifts of ~1.5 to ~2.0 kev are within the range of the previously reported values for the raw and corrected @x Math3-band relationship, respectively, and that the dispersion in the raw model is tighter than that of the corrected model. while the error in the @x math7- band relationship is not statistically significant,
in leptonic models for the high - energy emission of blazars, the @xmath1-ray emission is due to compton upscattering of soft target photon fields by the same ultrarelativistic electrons in the jet.   this picture, however, seems to be challenged by the detection of several flat spectrum radio quasars ( fsrqs ) that show strong optical  uv emission lines from a broad line region ( blr ), including 3c279, pks 1510 - 089 : *???   * ; *???   *. we have self - consistently investigated the dependence of the@xmath0 opacity due to the blr radiation field on the location of the #3  gev and #4   mev @x Math1-rays produced in the intense blr electromagnetic fields of these fsr qs. within the observational constraints  , we find that the presence of @x math0 absorption does not affect the required energy density of the vhe @x maths1- ray emission from these frsq - type blazar sources. as a result, we propose a new model for the origin of the @
the morphology of galaxies is of great interest because it reflects not only the structural properties of galaxies but also their star formation histories.   dwarf galaxies are predicted to be the most dominant type of galaxy based on cold dark matter cosmology, but the detailed morphological types of these galaxies are still not well understood. in this study, we used the color images of the sloan digital sky survey ( sdss ) data release 7 ( dr7 ) to classify the morphological groups of local galaxies with an emphasis on dwarf galaxies, whose morphological properties are still poorly understood. using the redshift range @xmath19, we found that the majority of the galaxies in the local group ( lg ) are dominated by dwarf galaxies which are much fainter than the bright end of dwarf galaxies. for the first time, we show that the redshifted galaxies from the sdss dr7 can be classified into two major types, namely, the dwarf elliptical ( de ) and the dwarf spheroidal ( dsph ) galaxies, which are both brighter and redder than the spherolytic ( sph ) galaxies. among them, the blue elliptical galaxy @xcite is a new type of
the swarm - based algorithms exploit the collective intelligence of the social groups in accomplishing different tasks.   these algorithms share remarkable features, such as decentralization, self - organization, autonomy, flexibility, and robustness, which have been proven very useful to solve complex operational tasks. in this paper   we propose a novel swarm intelligence optimization algorithm for solving complex combinatorial problems. it is inspired by the behavior of human groups and their ability to solve a very large variety of complex problems, even when the individuals may be characterized by cognitive limitations.. the proposed algorithm, hereafter referred to as human group optimization ( hgo ), is developed within the methodological framework recently proposed by carbone and giannoccaro to model the collective decision making of human Groups.    the proposed method is tested on a set of simulated annealing problems, including the traveling salesman problem, scheduling problems, facility location and supply chain design problems, and the production inventory problem. at the end of the experiment,   the results show that the proposed strategy outperforms the current state - of - the - art population - based optimization algorithms in most of the cases.
the possible effect of cosmic ray ( cr ) induced ionization on various atmospheric processes related to atmospheric chemistry and physics is debated over the last years.   we present the results of computation of ion production rate and corresponding ionization effect relative to the average due to galactic cosmic rays ( gcrs ) during the halloween sequence of ground level enhancements ( gles ) on october - november 2003 @xcite using a full monte carlo simulation of the atmospheric cascade based on a realistic atmospheric model nrlmsise2000 considering seasonal influence. in this study,   the propagation and interaction of high energy protons with the atmosphere are simulated with the planetocosmics code@xcite assuming a realisticmospheric model nRLmsise 2000 considering seasonal influences.. the ion production rates and the corresponding ionizations are estimated by superposition of the contribution of cosmic rays with galactic and solar origin as well as the contributions of solar energetic particles ( seps ) from the differential cosmic ray spectrum. for seps spectra in equation ( 1 ), which are considerably varying from event to event, we consider results derived on the basis of ground based measurements with neutron monitors. at the same time
nonclassical properties of electromagnetic field have been studied extensively in the past.   however, the interest on nonclassical states has been considerably escalated with the progress of interdisciplinary field of quantum computation and quantum communication in recent past as a large number of applications of non classical states have been reported in context of quantum computations and quantum communications. here   we study the possibility of generation of nonclassicals states in experimentally realizable simple nonlinear optical couplers using perturbative solution obtained by sen - mandal technique.. this type of asymmetric nonlinear ( quadratic ) optical coupler is prepared by combining a linear waveguide and a nonlinear waveguide operated by second harmonic generation of second harmonic generating generation. from the earlier studies @xcite we have reported lower order and higher order entanglement and other higher orderNonclassical effects in an asymmetric codirectional nonlinear Optical Coupler which is prepared for contradirectional propagation of fields. in the present work   it is found that the same type of system can also be used for constructing a compound mode involving second - harmonic mode. to study the possible generation of nontraditional characters of quantum states in this
the spin equation arises in many areas of theoretical physics and thus finds a wide range of applications, for instance, the semi - classical theory of laser beams, the absorption resonance and nuclear induction experiments, the behavior of a molecule in a cavity immersed in electric or magnetic fields.   the authors of @xcite give an overview of the known results and obtain new classes of exact solutions to this equation. among the methods of analysis of exactly solvable spin equations, the method of intertwining operators   plays a special role, since it reveals a new type of symmetry related with two - level systems shamshutdinova, czjp, called the polynomial pseudo - supersymmetry. in this respect, we would like to remind that the ideas and methods of supersymmetric quantum mechanics ( susy ) are recently coming into use in relativistic and nonrelativistic quantum - mechanical problems. here  , we show that a repeated use of simple transformations introduced in the above papers gives rise to a wide variety of exactlysolvable interactions for the spin equation.
hii galaxies are the strong emission line subset of the blue compact dwarf galaxies ( bcd ).   their optical emission is dominated by strong and narrow emission lines produced by the interstellar gas ionized by a young and luminous cluster, and their integrated optical spectra are indistinguishable from a normal hii region. in the majority of hii galaxies,   the emission lines are dominated by a low surface brightness, old, non - ionizing stellar population with an average age of about 1.5 billion years. however, many authors have found clear evidences of the existence of an old population of stars in these galaxies, which suggests that they are suffering at present a starburst, instead of being very young systems with a slow evolution. here   we review the evidence for a star burst in hii galaxy evolution and discuss the implications of this finding.
a new model of the photon - hidden photon system is proposed in the latest cast results of the bmv @xcite and gammev collaborations.   the model includes a massless hidden - sector photon ( here denoted as @xmath0 ) which is completely decoupled from the ordinary matter, i.e. it does not interact with the ordinary material directly and is coupled to it by gravity and possibly by other very weak forces such as gravity and/or gravity - like forces. for the mass region of the hidden field, the mixing angle between the ordinary photon and the hidden photon is given by the kinetic mixing of the two fields.    the experimental bounds on the mixing of these two fields are obtained from the results of experiments using the method of photon regeneration at the alps and lipss sites.  also, the sun is considered as a source of low energy hidden photons that can be produced through mixing with real photons.
quantum entanglement is one of the most important topics in quantum information theory.   it holds a fundamental role in quantum teleportation, superdense coding, quantum key distribution, quantum cryptography and has been proved to be necessary for an exponential speed  up of quantum computation over classical computation. in this paper  , we make a measurement of electron entanglements in two different examples of bipartite systems, as @xmath0 molecule and the dimer of ethylene, where each hydrogen atom or each ethylene molecule, respectively, can be considered a qubit. using the hartree  fock approximation method, we compare the von neumann entropy of the reduced density matrix for the @x math0 molecule with that for the@xmath3 molecule and show that the difference between the two is not statistically significant. by using the klein s inequality, we define the interaction electron entanlement in order to study the degree of entenlement in a bipartites system.
we explore the dynamics of a classical oscillator ( plasmonic oscillations on a nanometal ) coupled to a quantum emitter ( quantum dot, nitrogen - vacancy center or molecule @xcite ).   the system is composed of a quantum dot ( qd ) excited electronically with a nanoantenna operating at 800 nm and a dipolar split ring resonator ( srr ) excited by a quadrupole excitation of a quencher ( high - quality ) in the range of 0.1 - 2.0 nm.    the lifetime of the classical oscillators is extended due to the coupling and it approaches the longer life of the quantum emitters as the number of quantum emitters increases. for the latter,   an absorption window emerges at the resonance frequency where without microwave drive an absorption peak would have been observed. this phenomenon is called as electromagnetically induced transparency ( eit-like ). here, we show that such hybrid systems composed of coupled classical and quantum objects also display fano - like ( or eit - like ) resonances@xcite. when the two rabi oscillations are out of phase, absorption cancels and atom stays in the ground
the modulation - doped algaas / gaas heterostructure is a materials platform of great importance to the study of nanoscale electronic devices with quantum mechanical functionalities, and their development towards future technologies.   studies of low - dimensional hole devices are impeded by difficulties in making devices with high electronic stability and low noise / drift under electrostatic gating. here   we show that gate instability / hysteresis in p - type modulation-doped ( nh@x Math6)@xmath4s@x math7 ) algaa+/gaas+/p - type heterostructures caused by surface - state trapping and gate - induced charge migration within the doping layer is caused by a complex interplay between surface - states trapping and transport of charge from the gate to the semiconductor. using three different experimental approaches : first, we rule out direct charge leakage between the gate and semiconductor by studying devices where an insulator layer is deposited underneath the gates ; two insulators, al@xmatrix4o@x maths5 and polyimide, were investigated. although insulating the gates does not eliminate the hystereis, instead, it makes
brownian motion is a fundamental transport mechanism in nature and industry, with applications ranging from physics to biology, chemistry, engineering, and economics.   it is often considered as a continuous limit of lattice random walks, but this is not the case. in this paper, we present a simple and intuitively appealing representation of brownian motion that gives a closed formula mapping the unit interval onto the functional space of Brownian paths. here  , we show that sampling a brownian path is nothing else than picking up uniformly a point from the unit intervals. figuratively speaking, brownian movement is constructed by adding randomly wavelet - based geometrical features at multiple length scales. using the wavelet representation,   we find that the explicit formula elucidates many classical results aboutBrownian motion, including the non - differentiability of its path. moreover, we discuss fast simulations of brownia in confining domains, where one of the difficulties is the difficulty of simulating diffusion in high reynolds numbers.
in two recent papers @xcite, a new calculation of the phase shift of a matter - wave interferometer caused by the passage of a gravitational wave was presented.   this calculation was based not on the usual geodesic equation of motion ( eom ), but rather on the geode - deviation eom. in this paper  , we present a series of calculations that follow the two basic approaches in the literature used to determine the phase shifts caused by a gravitational waves.    these calculations are performed in transverse - traceless ( tt ) coordinates, where the gravitational wave is in the tt gauge, and the mirrors and the beam splitters are at fixed coordinate values in the same frame as the experimentally calculated phase shift. for both the low- and high - frequency limit,   the results show that the power - law dependence on the frequency of the gravitation wave is diametrically opposite to that of the expressions calculated in @xmath0, and that the difference is due to fundamental differences in the physics on which their derivations are based.
the intermediate polars ( ips ) are a group of stars that have been known for more than 20 years to have a spin  orbit diagram.   they are now considered to be one of the most active systems in the solar system, and there is growing evidence that they are actively active. here   i discuss areas of current activity, mainly from the observational side, and with an x - ray bias.
grover s algorithm is a quantum search algorithm which can speed up the process to @xmath4 operations.   one notable property of the quantum search algorithms is its oscillatory nature, i.e. the probability of finding one of the target states oscillates from zero to some maximum value. in @xcite,   an alternative way of solving the problem is proposed where the quantumSearch algorithm is damped by attaching an external spin to the quantum database. in this new scheme, knowledge of the number of target items in the database is not needed. in order to suppress the oscillation of the success probability as the search approaches one of these target states, a critical damping parameter   is introduced in the damped quantum Search algorithm. in our work, we obtain the optimized damping parameters up to the tenth iteration by calculating the absolute minima of the failure probability for a given number of targets and database size as a function of the damping parametrization per iteration. also, we compare the optimal damping with the non - optimized one.
the random phase approximation ( rpa ) was formulated for description of volume plasmons in bulk metals and utilized also for confined geometry mainly in a numerical or semi - numerical manner @xcite. in the present paper   we apply the rpa description using a semiclassical approach for a large metallic nano - sphere ( with radius of several tens nm, and with @xmath4-@xmath5 electrons ), in an all - analytical calculus version @xaite.   the electron liquid oscillations of compressional and translational type result in excitations inside the sphere and on its surface, respectively. damping of surface plasmon due to electron scattering and due to radiation losses ( accounted for via the lorentz friction force ) is included. the shift of the resonance frequency of dipole - type surface plasma frequencies, due to damping phenomena, well fits with the experimental data for various nano - spheres radii @xcites.. collective dipole / surface plaism oscillations in the linear chain of metallic nanosheets were then analyzed and wave - type plasson propagation along the chain was described @xi2-@i2/@i3.
we consider a circuit quantum electrodynamics ( qed ) setup with a semiconductor double quantum dot coupled to a superconducting transmission line resonator @xcite.   we find that by driving a current through a suitably biased double dot, a population inversion can be created between the dot levels, which then may lead to a lasing state in the resonator. using the coupling strength and tunneling rate of the double dot as parameters, we estimate the effect of the population - inversion on the transport properties of the system. for the high - q transmission line,   the population inversions is due to the presence of a single extra electron in the left or right dot, which leads to an increase in the number of electrons in the two singly charged states of the doubled quantum dot. at the same time, the emission spectrum and linewidth of the emitted emission spectrum are affected by the density of atoms in the double dots, which correlates with the tunneling rates of the systems. because of the narrow resonance window, this property not only allows probing the laser state via a current measurement, but also opens perspectives for applications for high resolution measurements.
a lower bound on the gravitational energy in terms of the global minimum of @xmath0 was rigorously proven within a specific anti - de sitter ( ads ) gravity theory by relating the hamiltonian charges to spinor charges.   arguments were given in  @xcite suggesting that these bounds hold more generally. however, it was subsequently discovered that solutions with arbitrarily negative energy can be constructed numerically for certain theories with @x Math8.    this raised a puzzle, which we resolve in this paper.. our resolution focuses on an auxiliary construct, the  superpotential " @x math9 built from the bulk scalar potential @x maths10., we show that the proof requires existence of a@xmath3-type superpotentials, while the examples of @xcites admit only the @xMath4-type. 	 we verify this claim below and also confirm various other details of the arguments of @xaite.
polarisation of the cosmic microwave background ( cmb ) is one of the most important tasks in the field of cosmological gravitational wave research.   the polarisation angle is assumed random and obeying the power spectrum derived from the high resolution radio observations, up to multipoles @xmath11. here   we review the current knowledge and forecast about the contamination coming from the diffuse polarised galactic synchrotron emission, which is the main foreground at low cmb frequencies. on the same frequencies,   several populations of extra - galactic sources are expected to be present, including the thermal dust emission, the free - free emission, and the galactic thermal dust with its own polarised frontiers. by analysing the data from the first year full sky maps of the wilkinson microwave anisotropy probe ( wmap ), we show that the distribution of these sources is different from that expected after the first years of wmap measurements, and that the concentration of the contamination is not as large as expected.
we present a new method for finding exact solutions of nonlinear differential equations, which greatly expands the method @xcite and which is free from the disadvantage mentioned above.   when working out our method we used the ideas of power geometry recently developed in@xcite. with a help of the power geometry we show that the search of the simplest equation becomes illustrative and effective. also it is important to mention that the results obtained are sufficiently general and can be applied not only to find exact solutions but also to constructing transformations for nonlinear linear differential equations.
the radio - pulsar system psr j0737 - 3039 b is the only binary pulsar known to consist of two radio pulsars : pulsar a and pulsar b. the spin orientation of both pulsars is tilted by more than 14 degrees from the orbital angular momentum vector.   we argue that this large difference between the two pulsar spin tilts is due to a single, impulsive " kick " from the supernova ( sn ) that formed pulsar p. b. using constraints on the sn kick magnitude derived from the orbit and kinematic parameters of the system @xcite, we find that this kick must have been displaced from the center of mass of the exploding star by at least 1 km and probably 510 km.
the origin of galactic magnetic fields is a long - debated issue, which relies heavily on good observational descriptions of the structure and strength of magnetic fields in a galaxy.   polarization observations of synchrotron emission at centimeter wavelengths have revealed that in nearby galaxies the intrinsic magnetic field " vectors ", i.e. * e*+90@xmath8 * b * with faraday rotation corrected, are impressively aligned along the optical arms of the galaxy @xcite. to determine the form of such directional coherence, we use rotation measures ( rms ) of pulsars and extragalactic radio sources to show that the direction of the regular local field in the galactic disk reverses between the perseus and the carina - sagittarius arms, but not between the crux - scutum arm and the norma arm. here   we discuss the implications of these results for our understanding of the origin of the current magnetic field configuration.
partial wave analysis ( pwa ) is widely used in physics analysis of high energy experimental physics.   it is used to search new resonances in a complicated spectrum, and to determine mass, width, branching ratio and spin - parity of an intermediate resonance. in the traditional pwa analysis,   the centrifugal barrier effects are considered. however, the influence of the centrifugal barrier effects to physics analysis is not considered in some physics analysis. in this paper, the effect of the center - of - mass interaction radius on the shape and partial decay width of a resonance is studied, and a method is proposed to measure the interaction radius in physics analyses.
the neutrino oscillation pattern in vacuum can get modified when the neutrinos pass through matter.   this is known as the mikheyev - smirnov - wolfenstein ( msw ) effects, which can be described by an effective hamiltonian. in our previous paper@xcite, we have given analytic expressions for the time - evolution operator in the 4-neutrino cyclic oscillation and the transition probabilities in the presence of constant matter densities. in the results of our calculations, the value of the matter density which causes the resonance varies with the average of the neut rino energies. in general, the resonance occurs when two of the energy levels approach to each other. in this article  , we propose to use the discriminant of the characteristic equation made from the Hamiltonian in matter in order to estimate the neutRino resonance conditions.
the minimal supersymmetric standard model ( mssm ) @xcite is one of the most popular extensions to the standard model of particle physics.   it consists in a symmetry linking fields with opposite statistics, matching thus a bosonic ( fermionic ) superpartner with each fermanionic ( bosonic ) standard model degree of freedom. among the most widely used versions of the mssms,   the minimal version dubbed the minimal supersuum - breaking variant (@xcite ) is the most well - known and has been proposed as a viable solution to the hierarchy problem of the universe. here  , we investigate the role of flavour violation in the breaking of supersymmetry in the context of an anomaly - mediated susy - breaking ( amsb ) scenario where the quantum effects of the superconformal anomaly are large compared to those of the other sources of Supersymmetry - breaking, which are subdominant. using experimental data from the tevatron at fermilab and the lhc at cern, we impose current experimental constraints on the flavour - violating amsb scenario and perform scans of the parameter space for the production of at least one gluino.
the swift burst alert telescope ( bat ) triggered and located grb090111 at 23:58:21 ut on 2009 - 01 - 11.   the swift spacecraft immediately slewed to the burst allowing the x - ray telescope ( xrt ) and the uv / optical telescope ( uvot ) to collect data starting @xmath9 and@xmath10 after the trigger, respectively. in this paper   we analyse and discuss how and if the extra soft steep decay emission of grb 090111 fits into different theoretical models ; particular attention will be devoted to the possible link with the detected soft prompt @x Math7 emission.
the pauli principle is encoded in the topology of clusters formed by lattice sites connected through the bonds.   clusters also carry a variety of interesting physical information, for example, sizes of certain clusters are related to condensates, the squares of the sizes of clusters yield susceptibilities and they are useful in building efficient algorithms close to critical points where the correlation lengths diverge since they allow non - local updates with a reasonable acceptance. here   we argue that cluster representations of the monomer - dimer - polymer systems with positive definite boltzmann weights yield useful algorithms directly in the chiral limit.
the quasar apm  08279 + 5255 was observed by the spitzer space telescope ( sst ) and the infrared spectrometer ( irs ) on 26 october 2003 and 23 november 2003.   the observations were preceded by target acquisition in the irs peak - up imager, and the data were reduced to a single - dimensional sky - subtracted spectrum of the target quasar using sky subtraction. for the low resolution spectra,   observations were obtained at two positions along the irS slit to enable sky subtractions. for high resolution spectroscopic observations,    the spectra were obtained of both the target and a blank nearby patch of sky that was used for sky subtractions.. the spectral energy distribution of the lensed quasar is well - fitted with the black body of temperature @xmath4220k at far infrared and submillimeter wavelengths and has a continuum level well above 70 mjy for observed wavelengths @x Math8 12@xmath2 m. the presence of large quantities of gas and dust in such a high redshift system makes it a prime candidate to search for complex molecules at very large lookback times.
the ability to coherently transfer quantum information between a number of qubits plays a crucial role in quantum computation and quantum communication.   the perfect quantum state transfer ( qst ) is still faced with many challenges in the experiment, since the fidelity of the state transfer is highly limited by the decoherence of qu bits, the quality of the transmission channel, and the imperfections during the experimental operations. in this paper  , we propose a scheme to overcome these challenges by utilizing quantum partial measurement.. the key point of our proposed scheme is that partial measurement is nondestructive and can be reversed with a certain probability, such that one can probabilistically project the state towards ground state which is insensitive to decoherent by a pre - partial measurement, and then retrieve the initial state with a partial measurement reversal. as a proof of concept, we demonstrate the feasibility of the proposed scheme in a superconducting phase qubit using circuit quantum electrodynamics.
the second law of thermodynamics is a statement about the possible time evolution of a dynamical ( hamiltonian ) system with a certain distribution of initial conditions.   recently, the violation of this statement in the case of a microcanonical ensemble of systems was discussed in several papers @xcite, where it is shown that if you know the initial energy of the system ( but not the precise initial state ), you can find a cyclic variation of external parameters such that the average energy of your system is reduced, and therefore work on average is extracted from the system by reducing its kinetic energy close to zero.see research article http://www.biomedcentral.com/1471-2148/7/8/17.
the theory of high - temperature superconductivity remains one of the most challenging problems in solid - state physics.   the central challenge is the connection of the ( known ) microscopic interactions at the level of electrons and ions, which are at high energy and temperature, with the " emerging phenomena" at low temperatures, i.e.  competing and nearly degenerate orders.    ideally, one should employ a systematic renormalization - group approach to integrate out the irrelevant degrees of freedom and, thereby, correctly bridge high to low energies and eventually go to @xmath4.,1 it is, however, by no means obvious how to do this when strong correlations are present, such as in the high-@xmath1 superconductors ( htsc ). in this context cluster techniques, which systematically approach the infinite - size ( low - energy ) limit,   provide a powerful alternative. in our earlier work @xcite, we have proposed a variational - cluster approach ( vca ) which provides a general variational scheme to use dynamical information from an exactly solvable " reference system" ( in our case, an isolated cluster ) to go to the finite - size lattice f
the marginalization paradox  ( mp ) is an apparent inconsistency in bayesian inference that can arise from the use of improper priors.   it was discovered in 1972 by dawid and stone, and has long been considered a serious challenge to objective bayes, the approach of harold jeffreys and edwin jaynes, in which a certain state of information is represented by a unique prior. recently, i have shown that the mp can be resolved if probability limits, rather than formal posteriors, are used to define improper inferences. in this paper  , we reconsider the differences between jayne and zidek, and show that the differences hinge on a single assumption, which might appear as a mere technicality : that the problem of improper inference can be solved if the proper prior is defined by a pointwise limit. using this assumption,   we find that the problems in which the inconsistencies arise are ordinary problems of statistical inference, although they need to satisfy certain symmetry properties. however, they are not ordinary problems ; they are more difficult to solve when the prior is improper, and the results are usually incompatible with the results of the other way around. for most of the problems previously leading
a self - consistent description of electrons, magnons, phonons and other fermionic and bosonic degrees of freedom in solids is still a challenging problem for strongly correlated systems where the simplest approximations are usually not sufficient. here   we construct a theory, that is capable to describe systems with strongly correlated electrons interacting with collective bosonic modes.   these modes can appear explicitly in an original hamiltonian or arise from electron - electron interactions. among numerous examples of such systems   are the cases of weak itinerant ferromagnets @xcite and, more generally, any materials near quantum phase transition points@xcite. by combining the dynamical mean field theory ( dmft ) approach with realistic electronic structure calculations,   the theory is able to provide a generalization of the gw+dmft approach to non - local interactions and consistent descriptions of collective boson excitations @xcites.
a large class of physical and engineering problems can be described in terms of lagrangian and hamiltonian systems, such as controlled mechanical systems, externally forced and dissipative systems, collisions, electric circuits, stochastic systems, and field theories such as electromagnetism and elasticity.   dirac structures are known as a powerful tool for providing a natural geometric framework for describing the structure of such diverse lagrangia and hamilsias on the product of configuration spaces by introducing nontrivial constraints that model interactions between subsystems, which is called an  interconnection.  recently, it was shown by @xcite that any power - conserving interconnection of implicit port - controlled hamiltonians ( ipch ) systems is another port - hamiltonic system, with the dirac structure being the composition of the constituent parts, Hamiltonian the sum of the hamiltonists, and resistive relations determined by the individual resistive relationships. here  , we review the literature on the interconnections of ipch systems and show that the interconnection can be represented by the integration of a plant diracructure with a controller dirac structural for the control of the electrical components of the plant port
the equilibrium state of the vortex phase in soft magnetic permalloy caps on self  assembled spherical particles is studied by combining analytical methods and micromagnetic simulations.   the results show that the geometry of hemispherical shell results in a significantly modified phase diagram without a uniform easy  axis state in comparison with extruded hemispheres, which is characterized by the quasiuniform magnetization structure for the monodomain state. to study the vortex ground state we propose a simple analytical approach, which allows us to describe different states and transitions between them.
pulsar wind nebula ( pwn ) is a broadband synchrotron - emitting bubble formed by the outflow of a pulsar wind from a supernova remnant ( snr ).   it is a non - thermal radio source that can be observed from the radio to @xmath1-rays. here  , we investigate the magnetic field structure of a pwne containing a recently crushed snr using the molonglo observatory synthesis telescope ( most ) and the einstein observatory s snr survey @xcite. in the radio regime,   the pwn is characterized by a centrally filled morphology and a flat spectrum, with a spectral index of@xmath2 ( @x math3 ). for the x - ray regime, the pwens are more complex, with an off - centered main body and a circular main body with a finger - like structure protruding northwest from the main body. at the same time, the outer shell of the pnwens is covered by a diffuse thermal component covering the radio shell and a long head that is elongated toward the center because of the reverse shock interaction between the snr and the pulsar. during the reverber
the experimental results of a quantum - dot - embedded aharonov - bohm interferometer on the measurement of magnetic - flux - dependent interference signals and the extraction of the phase of the transmission amplitude of an electron traversing a quantum dot are presented.   the experimental results show that the transmission phase drops by @xmath0 almost suddenly in many conductance valleys and the transmission wave behaviors near two neighboring resonance peaks are the same ( up to ~@xmath1 ) instead of showing a relative shift by @Xmath0. since the friedel sum rule, which relates the determinant of the scattering matrix with the number of electrons in the system, reduces to the strictly one - dimensional form in systems without any transverse degrees of freedom and without any side branches, the experiment results are not compatible with the predictions of the friedle sum rule.
we demonstrate a single phonon coupling rate of @xmath1 hz from dispersive interaction of negatively charged nitrogen vacancy ( nv(- ), hereafter referred to as nv ) spins with a mechanical resonator in a diamond cantilever.   this is a significant improvement over existing experiments that rely on strain - mediated coupling of nv spins to mechanical resonators, and is an important step towards the strong coupling regime for quantum two level systems ( qubits ) strongly coupled to mechanical modes.
the accretion of relativistic jets from a black hole is a well - known phenomenon.   the mechanisms by which these jets are launched have long been the subject of investigation and speculation, but the current consensus focuses on a combination of large - scale magnetic fields and the rotation of either the central hole, the accretion disk, or both. in this paper  , we investigate the effects of the field topology of the initial field on the rate of accretion and the properties of the jet poynting flux. using fully general magnetohydrodynamic ( grmhd ) simulations, we find that a purely toroidal initial field leads to a systematically smaller accretion rate than one with an initial field that is dipolar, and that the jet can be effectively accelerated along the field lines that form the outer edge of the torus when the field is arranged in loops of alternating sign within the initial gas torus. however, even with the same initial field, there is a significant reduction in the time - averaged jet poys due to the presence of a vertical field line in the initial torus, and this is accompanied by a significant enhancement in the mean mass accretion rates and the timescale of the
understanding transport of charged solutes across the cell membrane is a problem of paramount importance in biophysics, since it is crucial to regulate many cell functions.   this task is undertaken by transmembrane channels, so the characterization of the permeation of charged particles, ions in particular, is essential. in recent years, the increase in computer power and the development of new algorithms have permitted the study of ion transport through certain nanochannels employing all - atom molecular dynamics ( md ) simulations. here  , we present an approach to obtain diffusion coefficients of ions in the interior of the ompf porin, which are central input parameters in many theoretical descriptions of ion permeation. using the einstein relation for the mean square displacement ( msd ), we find that the diffusion coefficient of ions along the axis of the channel can be obtained by averaging the local diffusion coefficients over slices of the pore with respect to the distribution of the diffusion coefficients along the channel s axial direction.
shell model calculations of nucleon - nucleon (   n - n ) effective interactions in different shells of @xcite have been carried out to explore the effect of p - h excitation from (@xmath4 configuration ) and ( @xmath5 configuration ) on the transition densities for different excitations in the interior of nucleus.   the experimental results are compared with the theoretical results by looking at the contributions of the different effective interactions within the shell model using a new approach based on the regularization of the nucleonic interaction hamiltonian into monopole and multipole fields, which are then used to compute the effective interactions. among the various effective interactions, the p+qq empirical effective interactions are the most suitable for the study of the influence of different intrinsic factors on the shape transitions in the internal shell of nuclei.
a tree space @xmath7 is a homeomorphic space of trees with internal edge lengths that sum to 1.   it is a pure simplicial complex composed of chambers glued together by gluing associahedra and permutohedra in a particular arrangement, and has a cat(0)-structure, enabling the computation of geodesics and centroids @xcite. here  , we describe the construction of this space from local gluings of simplices based on covering by classical polytopes that encapsulate algebraic information, notably the associal and the permutohedral polytopes. using this approach, we show that the structure of @x math7 can be reinterpreted in the polyhedral context, and that its one - point compactification is homologically homotopy - equivalent to the geometric realization of the poset of partitions of the partitions of@xmath1 ( *???????)where the associated homology representations are fundamental in the theory of operads.
the coulomb gauge is the unique gauge that trivialises the dominant part of the static dressing for a static charge in qcd   @xcite.   we show that this is the case for monopoles and vortices, where gauge invariant formulation does not yet exist. understanding this connection   is of central importance if we are ever to understand fully their roles in the non - perturbative structure of qcd.
white dwarfs ( wds ) are the final destiny of the evolution of low and intermediate mass stars.   the majority of the presently observed wds are post - asymptotic giant branch stars, but a small number of them have a low mass he - rich core. in this review   we will discuss the relationship between the observed cooling sequences of wds and the theoretical initial - final mass relation, as derived from stellar evolution models, and compare the results with the results of the astereoseismology applied to wds. for each of these two scenarios,   our results show that the age - luminosity relation for wds is inversely proportional to the power of the luminosity, so that the cooling time scale may be used to derive stellar ages. on the other side  , an accurate comparison between the predictions of the theoretical models with specific observations of wd sequences could provide a better comprehension of the physical properties of high density matter.
@xmath0 is the cross section of the pure qed process in the energy region from hadron production threshold to the @xmath3 pole and recently to the energy of w pair production @xcite.   the measurements of @x Math0 in the low energy region were performed 15 to 20 years ago in novosibirsk, orsay, frascati, slac and hamburg   @xcites. for center - of - mass ( cm ) energies below 5 gev, the uncertainties in @x math0-values are about  15% on average ; and the structure in the charm threshold region is not well determined. a new cross section measurement in this region is needed to clarify the structure.
recurrent novae are one of the subclasses of cataclysmic variables ( cvs ) which are binary systems containing a white dwarf as an accretor and a mass - donor star filling its roche lobe.   the recurrent nova ciaql is a peculiar eclipsing binary system showing 0.6  mag depth of primary eclipse with an orbital period of 0.618355  d @xcite. in april of 2000,   two outbursts were recorded, and the object was classified as a possible nova based on the spectroscopic observations. here   we report the photometric observation of the second outburst of the object by lrcccc & hjd ( @xmath12450000.0 ) and error & site@xmath3 + & && & + mar. from july of 2001 to december of 2002. at the time of the first outburst, the optical spectrum showed higher - excited emission - features of heii and ciii  niii complex on a reddened continuum, while all balmer lines were detected as absorption lines. during the late part of the outburst, there was a rapid decline of the absorption lines due to the erosion of
the interplay between single - nucleon and collective motions is important in describing actual rotational excitations in nuclei.   the so - called magnetic and antimagnetic rotations are two typical examples as they are attributed to the gradual alignment of two angular momentum vectors of valence particles and/or holes with a specific orientation. for magnetic rotation, the energy and the angular momentum increase in terms of the shears mechanism ; i.e., the alignment of the high-@xmath3 proton and neutron angular momenta. for antimagnetic rotation, however, the two blades of protons or neutrons are aligned back to back at the bandhead, and then simultaneously close with respect to each other while generating the total angular momentum. here  , we use the tilted axis cranking density functional theory ( dft ) framework to investigate this interplay in the case of nearly spherical nuclei, where the collective rotation could be very weak due to the small deformation, while the valence nucleons play a crucial role in the generation of angular momentum by coupling the collective and single -ucleon motions. based on the results of our calculations, we show that the two - shears - like mechanism is not
we define the class of _ piecewise - linear systems _ ( abbreviated by * pwl*s ).   we formulate the realization problem for this system class and partially solve it by providing necessary and sufficient conditions for existence of a realization. in addition, we present an identification algorithm for systems with full observations which is illustrated by example of physical and biological relevance.
the dirac - weyl ( dw ) equation is used to describe the electronic structure, transport, and magnetic - field - induced phenomena ( aharonov - bohm ) in graphene nanostructures such as nanoribbon junctions and rings.   the dirac equation is formulated in terms of a position - dependent mass term of alternating sign ( with the spatial mass - profile connecting@xmath9 with @xmath10 ).    the solution of this generalized 1d dirac soliton is a soliton characterized by having zero energy and by being localized at the domain wall. from the above   we conclude that in the two extreme size - domains, that is a two - dimensional infinite graphene sheet and a one - dimensional carbon nanotube, the ab initio Dirac equation can be used to explain the transport of relativistic particles through molecular junctions.
the evolution and properties of active galactic nuclei ( agn ) are tightly linked to the properties of their hosts galaxies, and the environment that these host galaxies inhabit.   the most clear example of this comes from radio - loud agn, which have long been known to be primarily hosted by giant, massive, elliptical galaxies, which are predominantly found in very dense environments. however, recent studies have shown that obscured agn can also be found in similar environments to their more powerful hosts, and that they may even cluster in close proximity to each other. here  , we use the mid - infrared ( mid - ir ) region of the 2df qso redshift survey to investigate the clustering of obscured agns out to @xmath17 in the botes field. using a simple selection technique based on irac colors that identifies luminous agn essentially independent of their obscuration, we find that nearly all of the unobscured agn are clustered in regions with similar density and radio power to their rich host galaxies, but only a small fraction of them are found to be located in areas with significantly different spatial clustering strength. for the most part, these clusters are dominated by galaxy halos of
the mechanism of the particle number production is a very important issue in baryogenesis and leptogensis.   we propose a model for particle number violating model which consists of a heavy neutral scalar and one complex scalar. using the non - equilibrium field theory with the density matrix, we study the time evolution of the particles associated with the complex field by computing the divergence of the u(1 ) current with some initial condition specified with the densitization matrix. when chemical potential is zero, the initial particle number at @xmath18 is given as, l(0 ) & tr ( 0 ) + & = &. when there is a chemical potential of 0, the first particle number is found to be positive and the second one is negative. on the other hand, if the initial quantum statistical state is an initial quantum state, the rate of particle numbers production is higher than that of the pure state. in the next section, the current associated with this particle number   is written in terms of a green function of non - equilibration field theory. in sections ii and iii,   the particle size production rate is computed and its property is discussed. in section iv,    the particle
we establish diffusion approximations for catalytic branching processes that model the dynamics of catalyst - reactant populations in which the activity level of the reactant depends on the amount of catalyst present.   we consider a setting where the catalyst population is maintained above a positive threshold through a specific form of controlled immigration, where the reaction network is regulated by keeping the levels of certain types of molecules above a threshold in order to maintain a desired level of production ( or inhibition ) of other chemical species in the network. using stochastic averaging and diffusion models, we establish a limit model for the limiting catalyst reflected diffusion under two different scaling regimes ; in the first setting the catalyst and reactant evolve on " comparable timescales," while in the second set the catalyst evolves " much faster" than the reactants. in the latter setting, the limit model is described through a coupled system of reflected stochastically differential equations with reflection in the space @xmath3.    the limit theorem is based on the ergodicity result, which says that under a suitable " criticality from below " assumption on the catalyst dynamics, the limiting agent admits a unique stationary distribution, which takes an explicit stationary distribution.. the method is
nuclear stellar clusters are a common phenomenon in spirals, having been detected in 50 - 70% of these sources.   they are a natural consequence of the star formation processes in the central region of spirals. on the other hand, evidence has been accumulating during the past few years about the ubiquity of black holes in the nuclei of galaxies and the tight correlation of the black hole mass and stellar velocity dispersion implies that the creation and evolution of a black hole is intimately connected to that of the galaxy bulge. recently, in a hst survey in the virgo cluster, ct et al. have detected compact sources in a comparable fraction of elliptical galaxies with masses that scale directly to the galaxy mass, in the same way as do the blackhole masses in high luminosity galaxies. since seyfert 2 nuclei exhibit a featureless continuum ( fc ) that comprises much of the near - uv, it was long - thought that this fc was light from the hidden seyFert 1 nucleus.. however, recent studies have shown that the fc is also produced by a circumnuclear starburst that originates from a nuclear starburst. here   we review
landauer ( 1961 ) showed that any erasure of information is accompanied by an appropriate increase in entropy.   this result was then used by bennett ( 1982 ) to exorcise maxwell s demon in a szilard - like set - up. here   we show that landauer s erasure entropy limits the increase in the amount of entanglement ( more precisely, it limits the average increase ) between two quantum subsystems when each one is manipulated separately and this will then lead to an entirely new derivation of known entangler measures such as the relative entropy of Entanglement and the entanglements of creation. in order to become more familiar with landauer’s principle we first analyze classical error correction and compare it to quantum error correction using the concept of erasure.we demonstrate formal analogies between classical error corrections and a thermodynamical cycle in general. in section 3 we repeat this analysis using quantum errors and derive the most general statement for information erasure. in sections 4 and 5 we apply landauer ‘s principle to explain recent measures of entanlement, and link it to the principle of  no increase of entenuity by local means . from two different points
quantum molecular dynamic ( qmd ) simulations of the equation of state ( eos ), viscosity, and diffusion coefficients for hydrogen ( h ) and helium ( he ) mixtures under extreme conditions of high pressure and temperature are presented.   the qmd results are compared with the results from reduced models and qmd based linear mixing models. in the present work,   qmd simulations of h - he mixtures have been performed by employing a plane - wave finite - temperature density functional theory ( ft - dft ) description, where the electronic states follow the fermi - dirac distribution and the ions are quantum mechanically treated through fe2 + -dft and ions move classically. using the vasp @xcite simulation package, qmd calculations of self - diffusion, mutual diffusion, and viscosities for h -He mixtures at temperatures from 0.1 to 8.0 to 10 ev and equivalent h mass densities of 0.01 to 1.0 g / cm2@xmath1 @xcites have been carried out. among the standard mixing rules, the self and mutual diffusion coefficients of h- and h-mixtures are found to be independent of each other.
the lhc is about to probe the physics of the tev scale.   it holds great hope to discover new physics beyond the standard model and shed light on electroweak symmetry breaking and dark matter. in this paper   we propose a new observable physics object at colliders  an anomalous underlying event.we consider a new physics scenario in which some new particles with a mass of several hundred gev are pair produced at the lHc. 	 the new particles are charged under a new strong force and are thus confined to a single highly excited mesonic bound state. after production, the excited bound state will emit soft radiation, and decay to the ground state, emitting many quanta that will be studied and characterized for a variety of hard final states in terms of distributions of soft tracks and unclustered energy. as a result,   the underlying event ( ue ) will be found to contain a distinctively uncharacteristic distribution of soft track and diffuse energy when compared to a characteristic ue with a similar hard final state. if discovered, these signals may give us new and complementary information about the new physics at the Tev scale.the signal and its search strategy are best explained in
radio sources are divided into two distinct morphological groups of objects : fris and friis.   the nature of the fr - division is still an open issue, as are the details of the evolutionary process in which younger and smaller gigahertz - peaked spectrum ( gps ) and compact steep spectrum ( css ) sources become large scale radio structures. here   we present the l - band and c - band merlin observations of 44 low luminosity css sources selected from the first survey at 4.85ghz by using a new approach since the main criterion used for selection was not flux density but luminosity of the objects. among the 44 sources we find that approximately one third have a value of radio luminosity lower than the luminosity boundary found for fr sources @xcite, which means that they are compact young sources with luminosities comparable to fris. this finding supports the idea that there exist a group of short - lived radio objects that has been largely neglected to date.
d - branes are the natural candidates to probe the geometry of space - time beyond the string scale. in @xcite,   a number of d - brane probes of calabi - yau manifolds have been studied using fundamental strings, and it has been shown that they project out'the non - geometric phase of the vacuum moduli space, in agreement with the results obtained in@xcite.   this was found to be generally true for orbifolded conifold singularities of the form @xmath5, @x Math6, @Xmath7, @ xmath8, @xsmath9, @ysmath10, and @x maths11. in the present paper, we use toric geometry to investigate the case of the suspended pinch point ( spp ) singularity of the blowup of the @x math0 orbifold and the various partial resolutions of the ~14-residualised @xMath14 orbifolts that have been investigated in @xaqite, and show that the matter content and superpotential interaction of the gauge theory that probes the spp singularity can be reliably read off from the world volume gauge theory data for
we demonstrate that it is possible to identify an absorptive potential by measuring the short time dynamics of only the transmitted wavefunction of a delta function barrier in a turbid or diffusive medium.   the barrier is either imaginary or real, and the wavefunction at the other side is independent of the barrier for short times, while the temporal dependence depends on the exact nature of its barrier ( absorptive or not ).
the classical pion field configuration corresponding to the disoriented chiral condensate in high energy hadronic or nuclear collisions is a superposition of waves, which oscillate in the very same direction in isospin space.   this property is at the origin of the anomalously large event - by - event fluctuations of the neutral fraction of the _ total _ number of radiated pions. here   we show that the probability distribution of the above ratio is given by the inverse square root law ( see e.g.  @xcite ) and is to be contrasted with the sharply peaked binomial distribution one obtains in the case of incoherent pion production.
we study the static solution of the einstein equations that can describe the dark matter halo with the existence of the supermassive black hole at its center and the background of the spatially inhomogeneous phantom field in a galaxy.   we adopt the standard assumption that the dark mass halo consists of the weakly interacting massive particles ( wimps ) with the equation of state @xmath13 and find an approximate solution for describing this galactic halo scenario when we take the metric functions to be satisfied with@xmath15.    we also obtain the approximate solution by adding a cutoff in the momentum integral, which is obtained from the diffuse gamma ray background @xcite, and then compute the accretion rate of the phantom particles into the black hole. since the phantom dark energy field can cause the quantum instability of the vacuum at high frequencies, we treat it as an effective theory valid at low energy, i.e., we add a cut - off point for the acceleration of the universe where the density and pressure are equal to 0.5 mev and 0.1 mev, respectively.
the quantum hall effect ( qhe ) is used to conserve the unit of the electric resistance.   the value of the von klitzing constant @xmath5 has been used as the standard of resistance by many laboratory of metrology, because the relative precision of its measurement is better than that of @x Math6. in the present review   we are interested in the pre - breakdown regime, i.e. in the heating phenomenon which is observable before breakdown of the qhe. for the first time  , we have studied precisely the voltage drop between the source contact and the adjacent voltage contact in the Qhe regime using a well specified configuration for the measurement at the i=2 plateau where the temperature approaching zero is considered as the critical temperature for the onset of the quenching of the energy transfer from the electron gas to the two dimensional electron gas. with the help of an optical fir technique, we show that the dimensions of the samples influence drastically the measurements of the contact voltage drop in this pre - breakdown regime.
superconducting cosmic strings are known to carry large currents and charges.   this has important cosmological consequences, the most important of which is the possibility of forming vortons. in this paper   we extend a formalism that allows one to calculate vorton densities in any chosen superconducting string model, subject to some approximations. here   they are analysed at the intermediate energy scales, and the corresponding cosmologic bounds are discussed.
high - energy processes and high - energy particles play a pivotal role in the energy release, energy transport, and plasma heating during solar flares.   we observed a large solar flare on a k1  iii binary of the rs cvn type with a giant and a fainter companion ( @xmath0 gem ) during the gradual phase of a quiescentre - to - center transition ( cet ) on the dm5.5e binary uv cet, which is a close binary consisting of a k2   k3 giant and its companion whose spectral classification is unclear. at radio, euv, and x - ray wavelengths,   the coronal emission from the star is strongly related to the magnetic reconnection of the companion with the main - sequence or subgiant primary, but the source of the radiation is not well understood. here  , we show that the luminosity of the corona is proportional to the number of fast electrons injected into the system, and therefore to the power of the collision of the electron - ion beam with the chromosphere as it travels along closed magnetic fields. using a combination of optical ( u band ) and ultraviolet ( euv )
the fundamental plane ( fp ) is a two - dimensional surface in the space of parameters that reflect size ( effective radius ), density ( mean surface brightness ), and kinetic temperature ( velocity dispersion ).   a key feature of the fp is its deviation ( ` tilt') from the virial theorem, which may be interpreted as a variation of the m / l ratio along the sequence of early - type galaxies ( etgs ) and/or the breaking of homology assumption. despite all the observational efforts,   the origin of the tilt is still under debate. here  , we show that the tilt can be explained by a change in either the stellar population ( e.g.  @xcite ) or dark matter content with galaxy mass ( i.e. @xmath3, @xmath4, and @x Math5 ). using the same, large, homogeneous sample of etgs over the wide wavelength baseline provided by the r- and k - band data of the sloan digital sky survey and the ukirt infrared deep sky survey, we find evidence for the tilt to be wavelength independent from the optical to the nir wavelengths, interpreting this result as an increase
minuit is the gold standard in minimization packages used by high energy physicists.   it is written in fortran, which is no longer the lingua franca of computing in hep ; it can be awkward to link c++ code with code from a different language ; and modern users would like certain advantages relating to treating a minimization problem and its function, algorithms and domains as objects. we have asked a group of hep physicists who work heavily with c++ computation whether it would be a good idea to produce a c++ object - oriented minimizer with minuit s capabilities. about 40% reacted positively : " it s about time we had this!"
we have designed an experimental ice growth cell and light reflection technique that provides direct optical access to grain boundaries in ice.   the grain boundaries are large ( @xmath0 m ) conduits of liquid water threading throughout the solid polycrystal where three or more grains intersect and can be directly observed with optical microscopy. using this technique, we show that the thermodynamically stable grain boundary structure in ice is characterized by the measurement of the intensity of light reflection from a grain boundary as temperature and solute concentrations are changed. at the grain boundary,   crystallographic orientations and reflected light intensity are measured in thermodynamic equilibrium. for the first time, we describe the experimental apparatus and a procedure by which it may be used in order to characterize quantitatively the thermodynamics of grain boundaries within ice.
we construct solutions to five - dimensional einstein - maxwell - chern - simons theory with positive cosmological constant, based on atiyah - hitchin space.   we show that the base space ca nt can be written in gibbons - hawking form and that the black hole solutions interpolate between a bolt structure to gibbon - perry - sorkin monopole solutions on the boundary.    we also show that hyper - khler atiyah- hitchin geometries are not necessary for these solutions.
linear chains of scatterers represent a useful model of macroscopic structures like multi - layered structures, real - life wires, nano - tubes etc.   the main approach of theoretical analysis of these chains is the transfer matrix formalism. in this paper   we examine linear chains of abstract quantum scattrers using the dynamical approach to scattering and derive some interesting transport properties of the chain in three different cases : translationally invariant chain, chain with weak disorder and chain with strong disorder. for the first two cases, we show that the scaling of haar measures of scattering matrices corresponding to ballistic and localised dynamics can be obtained by re - derivation of known transport property of one - dimensional lattices from a simple new dynamical perspective, in particular for the case of single- and multi - channel scattchers.. however, in case of multi - channels scatterer we report some new - numerical - results on the scaling ( polynomials ) of haare - mello - pereyra - kumar ( dmpk ) scaling equation for the distribution of transmission - like - quantities of individual modes with the chain length.
the formation mechanism of compact objects, neutron stars ( nss ) and black holes ( bhs ), is an unsolved problem in high - energy astrophysics.   the birth and evolution of x - ray binaries ( xrbs ) hosting a bh or a neutron star ( ns ) accreting from a stellar companion has been studied using pulsar proper motions and galactic position and/or line of sight velocities. in this paper, we use these data to investigate whether the observed galactic distribution of bh - xrb hosts can reveal something about how bhs are formed. for the ns case, we find evidence that some nss receive a low velocity at birth, whereas others receive a high velocity at formation ( so called " natal kicks ", nks ). for both nss and bhs,   we find that the magnitude of the nk at birth is a signature of the system's peculiar velocity with respect to the circular galactic motion. for each type of nk, we also find evidence for a different orbital parameter, such as the root - mean - square value of the height above the galactic plane of the bh- and ns - xrb, which is a
near infrared airglow emission from the atmosphere is a major source of noise in near infrared ( 12.5 ) spectra.   the problem is compounded by the fact that the background level on an oh line can be more than 3 orders of magnitude higher than that between it and the object of interest, and that even small amounts of spectral flexure in an instrument can leave a significant'p - cygni'signal - to - noise'effect. here   we present a new method for removing the oh emission from near infrared integral field spectra at the vlt which is based on the use of multiple integral field units ( ifus ) with separate blank sky and object fields. as a result  , one can not simply take a ` sky'spectrum from one spatial pixel and subtract it from another ; instead one must integrate the data into a longer time - series of individual frames, which requires exposure times of up to 510mins for each frame to avoid the noise being read - noise limited. using this method, we show that the noise generated by the oh lines can be completely removed from the subtraction of the sky spectrum by integrating the data over a long time series of frames, while the noise
many signal processing problems in engineering such as x - ray crystallography and diffraction imaging require signal reconstruction from the magnitude of its frame coefficients.   recently, reconstruction from frame coefficients without phase has been numerically addressed via semidefinite programming. here  , we pose the following questions : can we reconstruct the original signal from the norms of its @xmath2-dimensional subspace components by means of a closed formula?   also, can we develop strategies to reduce the number of required sub space components?we shall provide affirmative answers for a deterministic choice and a random choice of subspaces.
we study the lasing characteristics of triangular organic microlasers of different shapes with an emphasis on the role of symmetries and their absence.   the results show that the most dominant periodic orbit ( po ) is the fagnano s orbit for highly symmetric triangles, while for asymmetric triangles it is not known whether any po exists at all. in cases where even the shortest pos are long and complicated or the pos are even not known at all, the laser can be left free to decide which po is being favored.
electronic transport in ferromagnetic single - electron transistors with nonmagnetic metallic islands   both normal and superconducting  was measured by means of transmission electron microscopy ( tem ).   the electronic states in the nanometer range are characterized by a decrease in the junction resistance when magnetic configuration of the junction changes from antiparallel to parallel one, and by a rise in the tunnel magnetoresistance ( tmr ) when the junction configuration is changed from parallel to antiparallelic. at the same time, the current flow through the barrier is not affected by the change in the magnetic configuration but by the presence of a nonmagnetic insulating barrier between the two sides of the junctions. as in the case of gmr, the tmr is due to quantum - mechanical tunnelling of the current through the barriers, which is also observed in other types of double - barrier junctions with a small central electrode ( called an island ).
we present a quantum search algorithm for a search on the @xmath3 dimensional hypercube which is based on quantum random walks on regular ( quantum ) graphs.   the quantum walk itself is defined by a regular graph, a quantum coin flip ( equivalent to a local scattering matrix at each vertex ), and a shift operation. in @xcite,   a marked vertex is introduced in the form of a local perturbation of the quantum random walk. here  , we reinterprete the algorithm in@xcite and give estimates for the vectors spanning the two - level subsystems at each crossing and derive the leading asymptotics for the search times.. the search algorithm finds the central crossing at the marked vertex in @x Math10 time steps.
one of the central issues in extragalactic astronomy is to understand how and when galaxies evolve, and whether and how their evolution is related to environment.   we suggest here some thoughts about some current works addressing evolutionary studies, often in a butcher  oemler ( bo ) like style, mostly of technical nature, but with a strong impact on the final result. because of the lack of appropriate cluster samples, clusters of different masses at different redshifts are usually compared, much like  comparing unripe apples with ripe oranges in understanding how fruit ripens ", andreon & ettori ( 1999 ) showed that the optical selection of clusters is prone to produce a biased - hence inadequate - sample for studies on evolution : high redshift clusters with a large fraction of blue galaxies are over - represented in optical cluster catalogs by a factor two, with respect to identical clusters but without a bursting population. therefore, optically selected clusters should be use with extreme caution in bo - like studies.. it is well known that clusters are not an homogenous family of objects, all characterized by a single value of the fraction ofblue galaxies.,the choice of a fixed and unique absolute magnitude limit does not select
electronic phase separation ( eps ) in the cuprates has been generally interpreted in terms of charged stripes, but recent evidence for a second regime of phase separation suggests that antiferromagnetic stripes may terminate slightly beyond optimal doping, where superconducting properties remain strong, and that there is a second state above optimal doping.   we have constructed ordered stripe arrays, for which detailed tight - binding calculations are possible@xcite, and show that the charged stripes are probably stabilized by some competing order, either magnetic or paramagnetic. while the charge density wave and superconductor orders can exist on paramagnetic stripes, they are strongly modified by quantum size effects ( qse ) on single stripes, and d - wave superconductivity and an unusual form of charge density waves are both found to persist down to the narrowest stripes.
we investigate the phase - dependent dynamics of a closed - loop configuration, consisting of four transitions driven by lasers.   one ground state is coupled in a v - type structure to two intermediate states, which are themselves coupled to a common excited state in a @xmath1-type structure. for each transition,   the relative phase between the excitation paths determines the interference and hence critically influences the steady - state of the system @xcite. using a density - matrix formalism, we show that the steady state is determined by the concurrence of the phase dependence of the hamiltonian dynamics and the relaxation processes. as a function of the temporal lifetimes of the intermediate states  , the@xmath0 scheme can show a variety of behaviors including population inversion, coherent population trapping ( cpt ), and phase - independent refractive indices.
the cosmic star formation rate ( sfr ) is an important observable of our universe.   it is affected by a variety of physical processes, many of which are in turn regulated by the sfr, giving rise to so - called feedback loops. here   we report on another interaction of star formation feedbacks, using three - dimensional galaxy formation simulations that include star formation, photo - ionisation heating from a uniform ultraviolet background and/or kinetic feedback from core - collapse supernova ( sn ) explosions. for the high - redshift ( @xmath4 ) sfr  , we find that the inclusion of sn feedback amplifies the suppression of the cosmological sfr due to photo - heating. on the other hand,   the addition of photo - heated sn feedback also amplifies this suppression.. our results are relevant to current implementations of ( semi- ) analytic models of galaxy formation, in which the effects of photo / sn feedback are implicitly assumed to act independently of each other.
the _ einstein papers project _ is a long - term editorial project devoted to publishing the collected papers of albert einstein ( cpae ).   the first volume was published by princeton university press in 1987, followed by eight more volumes to date. to complete the series,   some twenty more volumes are anticipated during the next 3040 years. since its launch in 1987  , the project has launched a website jointly with the alberteinstein archives of the hebrew university of jerusalem.. the site presently provides over 3,000  high - quality facsimiles from einstein s autograph writings, a finding - aid to the alber einstein archives, and an itemized database of some 43,000 records.    the editorial project draws on the collection of the algerian archives, which includes the original dukas collection of scientific writings, drafts, notebooks, scientific and personal correspondence, and hardcopies from archives all over the world.
decision making ( dm ) is a complex process that involves the integration of sensory and motor information to form a set of decisions.   the mechanisms involved in this reduction have been under investigation for many years. in this study   we address a question complimentary to the issue of decision making mechanisms, namely, which neuronal units are involved in making perceptual decisions. for this purpose  , we determine dm activity in surrogate networks, defined mathematically as networks in which a complete control is present over stimuli, mechanisms, and responses. by means of a special correlation function, which determines contributions of units to dm, we define dm units for recurrent networks in a way consistent with the linear sensory - motor chains, thus satisfying the requirement of the correspondence principle.we first analyze simple linear chain models, and networks, such as trees, which have similar properties ; then use this analysis to define decision makers in networks of arbitrary connectivity. finally, we extend our study to the cases, when electric stimulation can be applied to units, and show that dm components can be identified in a manner consistent with our preceeding analyses.
the tidal debris of minor mergers have been studied using deep optical images of 15 such mergers.   the tidal debris contains star clusters with ages ranging from a few myr to greater than a gyr as well as masses ranging from @xmath5 to ~1.5 myr. in each merger, there are star cluster candidates ( scc ) with ages less than the tail age, which indicates that the star cluster formed in the tidalbris and was not pulled out from the central regions of the galaxies.    the lowest median mass of the star clusters are found in the early stage mergers of arp 269 and arp 279. 	 these two galaxies appear to be missing higher mass star clusters or that there is not enough material in their tails to form them.
the importance of thermohaline convection inside stars is now well established.   it can modify the atmospheric abundances, as observed in the so - called " chemically peculiar stars ", but it can also have strong implications for the stellar internal structure. in this framework, the accumulation of iron ( together with less important metals like nickel ) may have strong consequences, which are different according to the stellar type. in main sequence a stars, it may lead to the creation of an extra convective zone due to an iron - induced increase of opacity @xcite and this may explain the existence of evolved oscillating am stars. in the case of accretion of metal - rich matter onto main sequence stars,   the accreted matter does not remain inside the convective zones, but diffuses downwards @xcites.. the results of the stellar evolution computations based on the thermoconv theory are presented for a 1.7 @xmath6 star, which is assumed to have suffered some accretion from an agb companion.    the results show that the accretion occurs in the outer layers of the star, where it is mostly due to helium diffusion. however, some of the heavy matter falls down inside
we develop a fully microscopic stochastic theory of spin dynamics in the presence of an external magnetic field, taking account of pertinent scattering mechanisms.   our analysis is based on an innovative implementation of the two step relaxation process corresponding to the relaxation time hierarchy involved in ( a ) electron thermalization, and ( b ) spin relaxation. in the first stage of solution, we determine the relaxation rates and fluctuation characteristics of electron orbital motion due to coupling to optical and acoustic phonons and random impurities as a bath, and then analyze the spin relaxation process due to spin - orbit interaction, wherein the orbital degrees of freedom are considered as an  effective heat bath , having the characteristics determined in stage ( a).in the second stage, we derive a set of bloch equations with two distinct relaxation times ( longitudinal relaxation time, @xmath0, responsible for spin magnetic moment relaxation, and transverse relaxation time,@xmath1, responsiblefor decoherence ), which are used to derive the full heisenberg operator of the bath.graphical abstract
radiogenic heat, evidently, must be an important source of internal heat production.   the total heat flux is presently estimated to be about 40 tw, which, however, suffers from uncertainties due to the size of its local variations and inaccessibility of much of earth s surface. in this work  , we investigate to which extent liquid scintillator ( type ) detectors such as kamland and/or borexino can be used to help in discriminating among different geophysical models of heat production by measuring antineutrinos in the energy range @xmath15 produced inside the earth.. we show how much one can improve the quantitative understanding of the radiogenic contribution to terrestrial heat in about a decade of operation.
recent large - scale surveys of nearby molecular clouds have provided a solid statistical basis for addressing some long - standing questions about the formation of low - mass stars.   these surveys have clearly established that star formation is not evenly distributed over molecular clouds, but instead, star formation proceeds in a clustered manner, concentrated in regions of high extinction. using the criterion of @xcite of 1  pc@xmath0, 91% of the stars in the c2d survey and 75% of those in a larger sample, including taurus and all gould belt clouds within 500  pc of the sun, form in a cluster with a broad range of surface densities and no clear sign of separate   clustered " and  distributed " modes. this review will focus on the spectroscopic properties of the molecular cloud material and the forming star.
we propose a new way to obtain initial data for a binary black hole binary using a recently introduced horizon penetrating teukolsky formalism @xcite.   the initial data is obtained by evolving two non - rotating and non - spinning kerr   schild black holes that are separated by a few degrees of freedom from each other. in the " close limit " of the evolution,   these two black holes are superposed and their gravitational effects are like those of two stars that have been separated far apart but each is critically close to gravitational collapse. here   we show that the results obtained from this evolution are in agreement with those obtained by sarbach _   @xcite from their evolution of the same initial data family using a zerilli equation.
we report high - resolution mid - infrared imaging observations of the nearby, young, late - type binary hen 3 - 600.   we show that the thermal dust emission in the binary is due to one or both stars in the system, and compare the near- to far - infrared spectral energy distribution ( sed ) of the dust disk(s ) with observations of t tauri disks in taurus. at a distance of @xmath050 pc,   the two components of the binary are clearly resolved, with a peak - to - peak separation of 1.4  and a position angle of@xmath6, consistent with previous observations. using the oscir 4-m blanco telescope at cerro tololo interamerican observatory, we measure the flux ratio for the star in the k band, m band, n band, and ihw18 band at ~2.2, 4.8,10.8, and 18.2 myr, respectively, and find that the spectrum of the central star is dominated by a circum_binary _ disk around one or more of the two stars, with an average flux ratio of 0.967, 0.891, 0
the current paradigm for galaxy formation is based on the view that galaxies are the visible component of gravitationally bound systems dominated by dark matter halos, which form via gravitional collapse of density perturbations that become non - linear.   since galaxy properties, such as spin and shape, are expected to be affected by their host halo, alignments between galaxies and their large - scale environment are also expected in the current paradigm of galaxy formation. using @xmath3-body simulations, we have found that the spins and/or shapes of dark matter Halos are aligned with their host galaxies, and that the major axes of halos lie preferentially on the shells of voids, in the plane of sheets, and along the direction of filaments. however, the alignment signals found here are much stronger than those obtained in observations for galaxies, indicating that, due to complex accretion and merger histories, there is a misalignment between these two structures. moreover, we find that the alignment effects are found to depend on a variety of galaxy properties ( e.g., the size of the halo, the strength of the clustering strength, the spatial distribution of its satellite galaxies ).
we explore the optical properties of galaxies in a sample of 60 nearby groups, known as the group evolution multi - wavelength study ( gems ).   we find that the near - ir luminosity function ( lf ) of x - ray dim groups is significantly different from that of their bright counterparts, and that this difference is due to dynamical friction rather than rapid evolution through merger.
early - type galaxies are known to contain small amounts of cold interstellar gas and dust.   it is not well known whether this gas can be used to form stars, but recent studies have shown that at least a large fraction of these galaxies are forming stars. in this review,   we discuss the results of a recent study of low redshift early - type galaxy evolution using the galaxy evolution explorer ( galex ) and the sloan digital sky survey ( sdss ) which show that some of the sample galaxies have uv to optical colors consistent with recent star formation.
the meson d@xmath8(2317 ), discovered in 2003 at slac ( stanford linear accelerator center ) by the babar group @xcite, possesses a mass of 2317 mev, some 170 mev lighter than expected, at least according to prevalent theories of quark interactions.   hence physicists need a new explanation of how a charm quark attached to an antistrange quark should have this particular mass. in this work   we analyze the possibility that these three states ( or some of them ) are tetraquarks. for this purpose we perform a schematic study of the mass splitting of the charmed scalar @xmath14 meson and the nonstrange @x Math10(2308 ) meson using the x - ray photoelectron spectroscopy method. as a result  , we find that the two states are separated by a small mass gap which is more than ten times smaller than the size of the predicted mass difference between the two mesons. on the other hand,   the third state is divided into two states : the first state is found to be the first radial excitation of the d#xmath11(2112
the pamela experiment has recently reported evidence for a sharp rise of the positron fraction at energies @xmath0 gev, possibly extending toward even higher energies, compared to the expectations from spallation of primary cosmic rays on the interstellar medium.   these results raised a lot of interest in the astrophysics and particle physics communities, leading to many proposals trying to explain this excess. here   we review the most recent work on the indirect detection of decaying dark matter in the cosmic - ray electron - plus - positron spectrum by the h.e.s.s. collaboration.
psr b1509@xmath058  is a young, energetic pulsar that was discovered with the _ einstein _ satellite @xcite in 2006.   it has been observed regularly since 1996 with the proportional counter array ( pca ) aboard the _ rossi x - ray timing explorer ( rxte ) as a timing calibration source. here   we present a search of 14.7 yr of data from the pca for pulsed flux variations, pulse profile variations, and magnetar - like bursts using the time - series analysis of the pulsar s x -ray emission properties.    we also extend the timing solution for psr   b150 9@x Math058 by 7.1 yr, increasing the total observing time to 28.4 yr. these new data are used to refine the measurements of the second and third frequency derivatives of the braking index, @xmath15 and @x math16, and the second braking index of the spin - down model, @xaite, and to further quantify the variability of the pulse profile of @xMath17. during the latter period,   both the first and second braking indices were found to be significantly
the markov chain monte carlo ( mcmc ) method is a commonly used device for numerical approximation of integrals of the type @xmath0 where@xmath1 is a probability density function.   recently, there has been a number of publications describing different adaptation techniques aiming to find a good proposal automatically using the adaptive metropolis ( am ) algorithm, which is a random - walk metropolis sampler with a gaussian proposal. in general, such an adaptation may, if carelessly implemented, destroy the correct ergodicity properties of the original am algorithm, that is, that the proposed proposal does not converge to @x Math3 as it would for a bounded set of functionals. in this paper  , we show that the am algorithm can be adapted on - the - fly, continuously during the estimation run, without re - projections back to a fixed compact set, and that the resulting strategy preserves the correctergodicity property for any function bounded on compact sets and growing at most exponentially as @x math21.    our main result ( theorem  ) holds for the original process having a target distribution supported on  @x maths5
the term " soliton " entered applied mathematics in 1965.   it was coined by m.  kruskal and n.  zabusky for a special solution of nonlinear korteweg - de vries ( kdv ) equation, depicting solitary wave @xcite. in the 1970 s   the inverse scattering method was devised and its generalizations got a lot of attention. in 1975   i proposed a new model for 3 + 1 dimensional systems, allowing solitons. at the time of writing   my proposal was neglected for 20 years until my colleague antti niemi became interested and agreed to sacrifice a year to learn computing and devise the programm. since then we have an ample evidence, confirming my proposal @xmath2 = 0.5 mm    0.1, which shows unexpected universality of my model.    the variables, used in it, were shown to enter the list of degrees of freedom for several systems, having realistic physical applications @x math2 = 2.0 mm  < 0.01, which means that they can be used in quantum field theory. in this talk   I shall describe all these developments
nonlinear interactions in @xmath1 materials have long been used to produce nonclassical light, including optical parametric amplifier sources of squeezed states and spontaneous parametric downconversion sources of polarization - entangled photon pairs.   recently, franson @xcite has argued that his dispersion cancellation paradigm differs from that of steinberg _ et al., in that the former is nonlocal whereas the latter is not. in this paper   he reviews various classical strawmen that have been suggested as providing explanations for nonlocal dispersion Cancellation, and shows that each of them fails to reproduce one or more of the major features of quantum nonlocal Dispersion cancellation. here   we show that the key feature of nonclassesical - state nonlocal dispatch cancellation that is not reproduced by this classical counterpart is the high - contrast nature of the photocurrent cross - correlation pattern. using a combination of photodetectors whose joint state has a phase - sensitive cross correlation that is at the ultimate quantum limit, which is either at the quantum limit or saturates the tighter bound associated with classical physics, we find that the signature of non local dispersion cancellations is a peak whose width is the
the bk model of earthquakes is used to study the dynamics of a chain of tectonic faults, which is phenomenologically similar to real seismic faults.   the model uses a dynamical field which is updated synchronously over the whole lattice of sites at discrete time intervals, rising monotonically and uniformly up to a threshold value. once this threshold is reached at one site, the value of the field at this site is reset to some residual value, often taken as zero, while a fraction of the value by which it is decreased is distributed among its neighbours. in this paper  , we analyse the behaviour of the model using cellular automata techniques, which allow us to work with larger systems at less computational cost.. the results show that the model exhibits a behaviour for the distribution of events which agrees with the empirical power laws for the frequency distribution of magnitudes and for the temporal decay of aftershock rates.
the full characterization of the high - resolution spectrum of water vapour from the microwave to the ultraviolet is a prerequisite for modelling and understanding of various processes in many fields in chemistry, physics, earth sciences and engineering.   the present paper reports the related recommendation of another iupac task group ( hereafter called tg2 ) on " intensities and line shapes in high - resolutions spectra of water isotopologues from experiment and theory " ( project no.   2011 - 022 - 2 - 100 ) on the need to identify and adopt a reference line profile for high- and low - resolution spectroscopic studies which improved upon the current standard, the so - called voigt profile ( vp ). as a first approximation to get the resulting line shape, the convolution of an inhomogeneous doppler profile with a homogeneous lorentzian profile is commonly used. here   we report the results of a systematic review of the data available for the vp for all the major isotope transitions of water at different temperatures and pressure conditions. using these data, we have developed a new method for describing the line profile of the isolated spectral line of a water - phase transition from the
the faraday rotation measure ( rm ) of the plane of linearly - polarized radio emission due to the birefringence of magneto - ionic medium is a powerful method to observe the galactic magnetic field ( gmf ) as well as the intergalactic magnetic field.   we have used the rm data from the nrao vla sky survey ( nvss ) and the westerbork radio synthesis telescope ( wsrt ) to estimate the vertical strengths of the gmF and the extragalactic contributions of rm in filaments of galaxies. using the rms data, we find that the median value of rms toward the north galactic pole ( ngp ) is @xmath10, while that toward the south galactic poles ( sgp ) is ~@xmath12. based on the second - order structure function ( sf ) of rm at angular separations of @x Math17, we estimate that the galactic contribution is about @x math20 for the northern hemisphere, and the galaxy contribution is ~xmath21 for the southern hemisphere. by using the redshift distribution of polarized background radio sources against which rm is observed, we found that the root - mean -
polyelectrolytes are charged polymer with ionizable groups that dissociate ions in solution, leaving the charges of one sign bound to the chain and counterions in solution @xcite.   the rich conformational behaviour of these molecules can be finely tuned by changes in the ionic strength, ph, temperature and condensation agents @xcites.. however, the presence of the long - range electrostatic interactions in combination with the polymer elasticity make these systems difficult to handle both analytically and computationally.    we present a detailed calculation for polyelectrolyses in poor solvents in the presence and absence of salt using the hamiltonian based approach. here  , we show that the nature of transition from a globular state at low fraction of charges to an extended state at large fraction of charge occurs via the formation of metastable intermediate pearl - necklace intermediates - locally collapsed globules joined by narrow strings. depending on the ratio of the debye screening length and the size of the polymer, the rod - to - globular transition changes from discontinuous to continuous. as a function of the salt concentration,   this transition is brought about via the dissociation of the
fountain code and cooperative communication are two transmission strategies which are gaining popularity in recent years.   fountain code is a fixed rate scheme, where the source continuously transmits encoded packets until positive acknowledgement is received. by creating multiple paths between source and destination ( each subjected to independent fading ),   a diversity advantage can be exploited. here, a novel scheme that combines network coding @xcite and fountain codes transmission is proposed. in erasure channel, the scheme applies digital network coding onto fountain encoded packets of two consecutive blocks, and allows source node to transmit together with the successful relay. whereas in wireless channel, this scheme employs analogue network coding with appropriate power allocation. the performance of the scheme is then analysed numerically, and it is shown to improve the overall throughput in both types of channel.
the recent availability of large and systematic data - sets at several wavelengths makes this a good time to search for correlations among the global properties of galaxies, analogous to the h - r diagram for stars. in this paper  , we discuss the results of a blind search for neutral hydrogen gas at 21-cm in the sloan digital sky survey.   we find that the average surface brightnesses ( sb ) of early type galaxies are significantly smaller than those of late type galaxies, which are the most likely to have been formed and evolved earlier. since the effective sb of an exponential disc is 2.1 magnitudes brighter than that of its nearest neighbour, it is difficult to detect lsbgs ( i.e. very hot gas in the potential wells of giant ellipticals ) with column density sensitivity at the @xmath17 level, which in turn requires integration times per beam of several hundred seconds, which renders earlier blind surveys either too insensitive or too impractical to detect these objects. as a result, we propose a new method for detecting lsbg - like galaxies by using a combination of high - resolution transmission electron microscopy and light scattering techniques.
@xmath3ge @xmath4-decay was observed in the few experiments  @xcite, though some small disagreement exists.   the goal of the experiment is to reach of the sensitivity @x Math5 years and to a neutrino mass of the order @x math6  ev. for this purpose, the time projection chamber ( tpc ) in the magnetic field with its large track detector devis ( detector visualizing ) is operating at itep ( itep = itep + 1.0  kv )  . the experiment aims to investigate the observation of @x maths0xe @x mathematics7-decays in methane by means of high - resolution time projection of the decay events in the magnetized region of the plasma using the time digital converter ( tdc ).    the experimental results are compared with the results obtained from the theoretical calculations of the nuclear matrix elements.
the so - called s stars ( s stars ) are very young b - type stars, with orbital periods as small as 15 years, and move around the central dark object @xcite on randomly oriented eccentric orbits.   a number of mechanisms have been proposed to explain their observed properties, but so far none have been able to account for all their properties. in the following   we show how the dynamical interaction of two stellar disks at larger radii, as they are observed in the galactic center, naturally leads to the creation of s stars. using direct @xmath4-body calculations  , we find that the distribution of eccentricities and inclinations of the observed young stars orbits is consistent with an initial configuration of two relatively flat disks, since the less massive disk is destroyed over time due to dynamical interactions with the more massive disk. by using tidal disruption of binary stars on such eccentric orbits around the smbh, we show that the latter can be disrupted, leaving behind an s star and possibly a hypervelocity star.
the electroweak baryogenesis is a mechanism to explain the baryon asymmetry of the universe.   the difficulty of the standard model ( sm ) is that the strength of the first order electroweak phase transition, which must be strong enough for preserving the generated baryons asymmetry at the electroweak scale, appears too weak for the experimentally allowed mass of the sm scalar higgs boson. in this paper, we study the effect of the fourth generation of quarks on the strengths of the strongly first - order electro weaken phase transition in the minimal supersymmetric standard model and find that introducing an extra generation of fermions might also lead to a scalar top quark heavier than top Quark.
the heisenberg model of interacting spins is an oldest many - body quantum model  of a strongly correlated systems, important both from a theoretical and an experimental point of view. in this paper   we carry out a systematic study of nonequilibrium steady states in driven @xmath0 spin chain resulting from boundary gradients in the@xmath2 direction, transverse to the anisotropy axis.   our results show that the magnetization current should alternate its sign with system size, for any value of boundary coupling. on this basis  , we rule out the possibility of a ballistic spin current, which is typically observed in integrable @x Math0 model under other kinds of perturbations, such as bosonization, lagrange multipliers, exact diagonalization, lanczos method, quantum monte carlo method and dmrg method. within the lindblad master equation ( lme ) formalism,   twisting angles between the first and the last spin result in a complete suppression of the magnetisation current, making a setup with @x math14 the simplest nontrivial one.    we derive general symmetries of the model which indicate that magnet
it is generally accepted that accretion onto supermassive black holes ( smbhs ) is the major source of their growth during the periods of the active nuclei duty cycles.   this process spins up the smbh, resulting in that the mostsmbhs should be rapidly rotating. however, the general lack of observational evidence for gravitationally broaden iron k@xmath4 lines in the x - ray spectrum of mcg-6 - 30 - 15 leaves the issue of black hole spin as one of the most elusive questions in astrophysics. here  , we use the observed multiwavelength spectral energy distribution ( sed ) of m87 to determine the best fit of the adaf model to the observed tev variability detected by high energy stereoscopic system ( hess ). from radio to x - rays, the sed is dominated by emission from the accretion flow under a schwarzschild hole, giving the eddington ratio of @xmath12. using a self - similar solution of the adsorption - deceleration factor ( adaf ), we find that the rate of accretion into the black hole is ~1.5 times higher than the rate at which it would normally occur.
one of the major challenges of the field of dynamics is the presence of different energy scales in the problem.   far - from - equilibrium physics requires the knowledge of numerous energy scales which can differ appreciable, in direct contrast to thermodynamic physics where only energy scales small compared to the temperature dominate. in this article   we examine the scattering properties of cold atoms and introduce another important consequence of harmonically confined geometries : the universal properties of scattering dynamics at intermediate energy scales, or energies larger than the trap frequency but much smaller than the effective range of the harmonic confining potential.
the x - ray spectra of accreting neutron stars and black holes in binary systems typically appear to have at least two components.   the soft spectral component is thought to come from optically thick gas in the accretion disk, and the hard spectral component comes from hotter gas that fails to reach thermal equilibrium with its radiation ; the radiation intensity falls off with increasing photon energy roughly as a power - law, up to a cutoff photon energy @xmath1 beyond which the intensity drops exponentially. here   we investigate the nature of the soft and hard spectral components in a model of accretion by a black hole and a neutron star, and find that they are separated into two distinct substructures, one consisting of cooler, dense gas that for convenience we shall call the " disk " component, and a coronal component of hotter, tenuous gas. on short timescales, the hot gas cools by compton scattering low - energy " seed photons " to higher energies, and then the compton upscattered photons escape the system as the hard spectrum. on longer timesc scales,   however, the cold gas becomes hot and optically thin to absorption within some critical radius, so that the corona
the coupled dynamics of magnetizations in ferromagnets in the presence of the spin hall effect @xcite in bilayers consisting of an insulating or metallic ferromagnet and a nonmagnet are investigated by solving the landau - lifshitz - gilbert ( llg ) equation numerically for both longitudinal and transverse geometries.   the numerical simulation reveals that the in - phase or antiphase synchronization is observed in the transverse geometry, and the phase difference becomes a quarter of a period in the longitudinal geometry. on the other hand, in addition to them, in the self - oscillation state, it is found that these phase differences depend on the values of the gilberts damping constant and the dimensionless field - like torque strength. an analytical theory clarifying the relation among the current, frequency, and phase difference   is also developed.
the origin of relativistic jets in active galactic nuclei ( agn ) is a key unsolved problem in extragalactic astrophysics.   we have previously argued that the x - ray emission of low - excitation radio galaxies ( lergs ) is dominated by radiation from a parsec - scale jet, that they have no signatures of standard, cold accretion disks, and that they may show no evidence at all for an obscuring torus. here  , we use the xis and hxd to search for signatures that are related to a standard, cool accretion disk that is surrounded by a torus : ( 1 ) a @xmath16.4  kev fe  k@xmath2 line, ( 2 ) heavily absorbed continuum emission, and ( 3 ) the @x Math510  keV compton reflection hump ( @xcite ). using the 87-ks _ suzaku   observation of ngc6251 ( @x math6=0.0247 ), the xray brightest low -excitation radio galaxy in the 3crr catalog, we find that these features are not present in the nuclear x - rays of lerg s.
the nearest neighbor ( nn ) heisenberg antiferromagnet ( af ) on the corner - sharing kagom lattice is one of the most studied systems since it has all the ingredients such as low dimensionality, strong frustration, and low coordination number, required for a disordered " spin liquid " ground state.   the classical ground state has a continuous degeneracy due to the  weathervane " rotation of the spins@xcite and therefore no long range magnetic order is expected even at zero temperature. in this work   we present a new experimental study of the frustrated ground state of the kagoma nn af using a combination of two - dimensional ( 2d ) and three - dimensional theory. by replacing the fe@xmath11 centers by cr@x Math11 centers, we show that the ground state can be reorganized into a triangular structure with both positive and negative chirality. from the spin configurations  , it is clear that the classicalground state is not the only ground state which can be rearranged.graphical abstract
time lags between x - ray variations in different energy bands have been measured in a number of active galactic nuclei ( agn ).   the lags are both fourier - frequency and energy dependent. here   we present a time lag analysis of the archived xmm-_newton _ observations of the bright quasar pg 1211 + 143 ( @xmath1 ; marziani et al., 2007 ), during two consecutive orbits in 2007. using model - independent timing techniques down to the shortest possible time - scales with the intent of understanding its emission / absorption intrinsic properties, we show that the soft - to - hard time lags observed in the past are due to the presence of a distinct component, which is associated to the soft energy response of the emission spectrum from a compton - thin ionized layer of the absorbing gas.
cepheids represent a brief phase in the post - main - sequence evolution of stars that originally had masses in excess of @xmath1. as evolved objects they populate the cepheid instability strip in the hr diagram according to the manner in which they generate energy, depending upon strip crossing.   intermediate mass stars can become unstable to radial pulsation during shell hydrogen burning ( first crossing ), twice during core helium burning ( second and third crossings ), and according to some evolutionary models, once during shell heliumburning ( fourth and fifth crossings ). in all cases   the evolution of such stars through the stability strip should be associated with gradual changes in overall dimensions, and hence periods of pulsation : period increases for evolution towards the cool edge of the instability strip as the stellar radius grows, and period decreases for development towards the hot edge as the star radius decreases.the observed rate of period change in cepheids is closely related to strip crossing mode and location within the instability Strip.    we demonstrate the link in more detail with the aid of a theoretical hr diagram that depicts the location of the cetheid instabilitystrip according to parameters derived for milky way cep heids @xcite, along with gene
the faraday experiment is a well - known example of a pattern forming system, in which surface waves on a free liquid - air or liquid - liquid interface are excited by a sinusoidal vibration of the fluid layer in vertical direction at a drive frequency.   this system has the advantage of fairly short time scales in combination with a very rich bifurcation behavior. due to the parametric drive mechanism the mathematical description of the experiment is more complicated as compared to rayleigh - bnard convection or taylor - couette flow and the quantitative understanding is less advanced yet. here   we provide a measurement technique appropriate to quantify the surface elevation of faraday ripples using a finite difference scheme. for low viscosity fluids our findings   are expected to compare with the perturbation analysis of zhang and vinls ( zhang et al., 2011 )  at least at a weak supercritical drive. moreover, a closer comparison yields a reliable estimate of the validity range of this approximation.
the production of strange particles in nuclear collisions is an exciting subject in nuclear physics.   the most important ingredients for the proton - nucleus and heavy - ion simulations are the elementary cross sections for strangeness production. from the experimental data   we know the @xmath20 amplitude rather well whereas the@xmath21 cross section is not well determined, since before 1997 the available experimental data on the reaction were very scarce. to investigate the model uncertainties as well as the selfconsistency of the calculations  , we analyze the role of the kaon exchange mechanism for strangness production and investigate to what extent our results might be influenced by the model parameters. using the one - meson exchange model, we show that the rate constants of the total production cross section are close to threshold at energies per nucleon below the free @x Math13 reaction threshold ( @x maths22 ).. the k+ exchange mechanism is dominant at low energies and the x - ray absorption spectra of the interaction between the quark and baryon play a key role in the formation of the new quark - qluon plasma.
we study the role of mutations in the evolution of fitness and age characteristics of individuals in a simple age - structured population dynamics model.   our model is an extension of logistic dynamics in which the characteristics of an offspring are mutated with respect to its parent, and this may be reflected in attributes such as its birth rate and/or its life expectancy. when advantageous mutation is favored, the fitness distribution of the population approaches a gaussian, with the average fitness growing linearly with time @x Math0 and the width of the distribution increasing as @xmath3.    conversely, when deleterious mutation is more likely, a steady - state fitness distribution is approached, with each individual's fitness increasing linearly over time. in all three cases,   the average population age reaches a steady state which, surprisingly, is a _ decreasing _ function of the averages fitness.. qualitatively, as individuals become more fit, competition plays a more prominent role and is the primary mechanism that leads to premature mortality.
helioseismology is one of the possible ways to study solar physics. in this article   we investigate the possibility to exploit solar physics to study the so - called chameleon particles.   these chameleons are quantum fields with a mass which is an increasing function of the matter density of the environment and they have been originally introduced in @xcite. in the solar system the field outside the sun is determined, to a good approximation, by a thin - shell just below the solar surface that is covered by a lunar laser - ranging shell. when this mechanism is operative in the sun, where @xmath2 is the mass of the chomeleon inside the object ( e.g. the sun ) and @x Math3 is the radius of the object, deviations from standard general relativity can be detected. in particular, we make explicit numerical simulations exploiting solar models that take into account the presence of the Chameleon field.    interestingly, our solar models are _ inconsistent  with the standard observables of helioseismsic observations, namely, a ) the thickness of the convective zone ; b ) the helium abundance on the solar surfaces ; c ) the speed of sound as
the @xmath0 gauge boson is a massive neutral vector particle associated with the extra @x Math1 subgroup of an underlying group.   searching for this particle as a virtual state is widely discussed in the literature. in the papers @xcite of the present authors a new approach for the model - independent search for @x math0-boson   has been proposed which, in contrast to other model - dependent searches, gives a possibility to pick out uniquely this virtual state and determine its characteristics. by taking into consideration the relations between the effective low - energy couplings derived from the renormalization group equation for fermion scattering amplitudes, some kinematics properties of the amplitude become uniquely correlated with this virtual states and the @x maths0 signals exhibit themselves.
the simultaneous existence of complementary correlations together with the freedom to select which one to extract is the most important feature of quantum correlation.   this feature is also revealed by the bell s inequalities @xcite, which quantify quantum correlation via expectation values of local complementary observables. here  , we seek a way to directly reveal the essential feature of Quantum correlation from an information - theoretical perspective. in this way, we show that the genuine quantum correlation does not vanish under a change of basis, and can be characterized as the residual correlations remaining in the complementary bases.
@xcite is a type iii polar material that is used as part of zno / me / zno ( me = metal ) multilayer functional glass coatings designed to filter heat - generating infra - red solar radiation.   it has been shown that the lower ag(111)/zno(0001 ) interface may fail for reasons not yet fully understood, leading to a sizable cost increase in the manufacturing of these devices. to understand this effect, one needs to characterise the interfacial structure that arises from the growth of au on zn(0001).in this work we use surface microscopy techniques and density functional theory to investigate the electrostatic energy change when charge is moved from one surface to the other in the direction of the internal electric field of the unreconstructed slab.we find that the dipole moment of the semi - infinite crystal can be quenched by a direct charge transfer between the o - terminated and zn - terminated polar surfaces of @xcite, where the surface charge density is @xmath8. under hydrogen - rich conditions, the surface is best passivated by adsorption of hydroxyl groups, while under low hydrogen partial pressure the surface tends to form triangular reconstruct
the quantum choromodynamics ( qcd ) of the quarkonium state at finite temperature is investigated using lattice qcd.   we employ the anisotropic lattice, on which the temporal lattice spacing is finer than the spatial one @xcite, to obtain large temporal cutoff compared with the charm quark mass. in this way, we can obtain detailed information on the temporal correlators of the hadronic states at some temperature and discuss the possibility of the bound state at @xmath6.
we present a computational approach to study the vibrational properties of colloidal semiconductor nanoclusters ( ncs ) using _ ab initio  molecular dynamics ( aimd ) simulations.   we construct a sila - adamantane ( si@xmath0h@x Math1 ) cluster that has the @xmath3 point group symmetry, and use the born - oppenheimer approximation of the electronic structure to perform aimd simulations within the approximation of this cluster to study its geometry and vibrational spectra from fourier transformed velocity auto - correlation functions. in the range of 0.15 to 2.5 thz  , we find a blue - shift of the si - si vibrational modes with transverse acoustic ( ta ) characters and a red - Shift of the other vibrational mode with increasing temperature for the entire cluster as well as a broadening of all the vibratory modes with increasing temperatures. by taking into account the anharmonic effects of vibrations, we also calculate the inter - vibron coupling strength, taking all the an Harmonic effects into account.
hercules x-1/hz herculis is a binary accreting x - ray binary consisting of a neutron star and a stellar companion.   it is the only known intermediate - mass ( imxb ) system with a 35-day super - orbital cycle, of high and low x -ray flux states consisting of : main - high ( mh ) state covering phases 0 - 0.31, short high ( sh ) state spanning phases 0.57 -0.79, and two low states ( ls ), with flux that remains at @xmath6@xmath7 of the mh maximum, separating the high states. in the present paper, we study the spectral modulation with orbital phase of the system her x-2/hzHerculis due to reflected X - ray emission from the atmosphere of hz her. for the first time  , we have observed an anomalous low state during ls and for the second time during ls+ during the transition from the main high state to the short high state by using a combination of uv and euv spectroscopy and transmission electron microscopy. as the orbit of the neutron star moves closer to the companion star, some of the
we report the self - organization of magnetic wires on a non - magnetic nanotemplate of grooves, which is achived by a growth process out - of - equilibrium.   the samples were grown in an ultra - high vacuum chamber using pulsed - laser deposition with a nd - yag laser at. to achieve this we use a 10 kev reflection high energy electron diffraction ( rheed ) setup with a ccd camera synchronized with laser shots. monitoring rheed during growth we observe that the angle of the facets becomes stationary after a while, typically a few nanometers of nominal thickness. for the first time   we show that the stationary angle is close to @xmath11, consistent with facets of type \{210 } in fe @xcite and \{310 } in w@xcite.
the cepheid period - luminosity ( pl ) relation plays a major role in distance scale studies, which can ultimately be used to determine the hubble constant.   the calibrating pl relation currently used is based mainly on the large magellanic cloud ( lmc ) cepheids, as applied by the @xmath2 key project team @xcite and other studies. here  , we discuss the non - linear lmc pl relation in the optical bands, which is more consistent with two pl relations and a discontinuity at a period around 10 days. for the long ( @x Math10>1.0 $ ) and short period optical pl relations that are available in the literature - test, both the slopes and the zero - points ( zps ) of the pl relations remain unchanged, while the linear pl relation obtained from the ogle ( optical gravitational lensing experiment ) data is extended to the _   jhk (-band ) and _ jhjhk ( 2mass ) bands. using the standard equation for the propagation of errors ( poe ) to equation ( 4 ), we find that the random error for the lmc pulsation period in days for the
there has been much controversy over the number of small sub-@xmath5 particles in ice clouds.   measurements from forward - scattering cloud droplet probes suggest that these tiny particles are present in very large concentrations, with important implications for the cloud s microphysical evolution, its interaction with radiation, and remote sensing. on the other hand, there is evidence which suggests that these small particles are in fact instrument artefacts, caused by large crystals shattering on the probe inlet, with the detector then sampling the numerous tiny fragments. to better represent the small crystal observations,   ivanova _ et al.    ( 2001 ) have taken cloud droplets probe and 2d optical probe measurements from 17 flights through stratiform ice clouds, and used them to parametrize a two - mode size distribution for input into general circulation models.. however, if the measured concentrations of small crystals are genuine or not, equation  substantially under - represents their numbers. here  , we test this idea, using 17 months of continuous observations from the doppler lidar based at the chilbolton observatory in hampshire, uk, and compare the results to a forward model of ivan
we present a time - dependent jellium model of the ionic background of c@xmath0 in fs laser pulses.   the model is based on density functional theory ( tddft ), which has been successfully applied to metal clusters in laser pulses and to @xcite using synchrotron radiation for single - photon ionization measurements. with short pulses of different frequencies   we study the dipole response and ionization after excitation by short pulses at different frequencies as well as the photoelectron spectra of the excited state of atoms inside c@Xmath0 within the laser field. while the laser intensity direct multiphoton ionization is found to be the responsible pathway for ionization, the excitation of a giant resonance near 20ev is claimed to be responsible for the ionization mechanism. here   it is shown that this is not the case, but is rather the result of collective effects such as the formation of plasmons, vibrational degrees of freedom, or fragmentation.
we report the fabrication of highly hydrophobic coatings by self - assembling self - assembled self - walled carbon nanotubes ( swcnts ) on multwalled carbon nanostructures ( mwcns ).   the films obtained from the process described in the experimental section exhibit a hierarchical morphology made of micro- and nano - structures, resembling that observed in lotus leaves and rose petals where micro - papillae are made of nano - Papillae. since the former have a smaller characteristic dimension than the latter, we observed that a surface hierarchy naturally occurs by depositing layer by layer a swcncnt film upon a mwcsn film. moreover, we report for the first time the experimental wenzel - cassie - baxter phase diagram @xcite for a carbonnanotube surface, showing that the transition between the wenzels and cassies is caused by passing through metastable states.
class prior estimation in a nonparametric setting has been actively researched in the past decade offering an extensive theory of identifiability and a few practical solutions.   application of these algorithms to real data, however, is limited in that none of the proposed algorithms simultaneously deals with noise in the labels and practical estimation for high - dimensional data. in this work,   we propose the first classification algorithm, with class prior estimation, designed particularly for high-dimensional data with noisy labeling of positive data.we first formalize the problem of learning class priors from noisy positive and unlabeled data by extending the existing Identifiability theory for class prior estimations from positive - unlabeling data to this noise setting. using univariate density estimation, we show that we can practically estimate classpriors and the posterior distributions by first transforming the input space to a univariate space, where density estimation is reliable. then, we prove that these transformations preserve class prior and show that they correspond to training a non - traditional classifier.    we derive a parametric algorithm and a non parameteretric algorithm to learn the class priores. 	 finally, we carry out experiments on synthetic and real - life data and provide evidence that
cygnus x-2 is a low - mass x - ray binary containing a neutron star and a companion star.   recent spectroscopic observations confirm the low mass of the companion, but also show that the spectral type of her companion is, to within two subtypes, a9iii and that its spectral type does not vary with orbital phase. here   we show that these observations are not consistent with the existence of an intermediate - mass subgiant. in order to explore this possibility, we perform a series of binary calculations using an up - to - date, standard, henyey - type stellar evolution code ( kippenhahn, weigert & hofmeister 1967 ). for each binary - evolution sequence, one needs to specify what fraction, @xmath17, of the mass lost by the donor is accreted by the neutron star, and the specific angular momentum of any matter that is lost from the system. as a result, we find that the present parameters of cyg X-2 can be understood if, at the beginning of themass - transfer phase, the companion was a somewhat evolved star of mass @x Math12 that lost most of its envelope as a
we present an alternative mechanism for generating an accelerated expansion and negative equation of state that does not rely on a vacuum energy. in our model,   a fundamental field spontaneously breaks lorentz invariance by developing a non - zero vector expectation value that thus " picks" a particular direction in spacetime. just as in the case of the higgs field in the electroweak theory, the vacuum energy of the condensate is set to zero.   the fermion gas of such coupled particles behaves like ordinary radiation at high energies ; however, at temperatures comparable to the mass of the fermanion, this gas behaves as if it has a negative equations of state. in the remainder of the paper, we discuss realistic scenarios in which particle dark energy can explain the late - time acceleration.
star formation occurs primarily in atomic and molecular interstellar gas, although around a massive enough star, even ionized gas can be accreted.   recent advances in our understanding of the origin and dynamics of that gas and its relation to star formation have led to new insights into the evolution of the milky way.
the oscillating cantilever - driven adiabatic reversals ( oscar ) technique is the most promising magnetic resonance force microscopy ( mrfm ) technique for spin - based atomic scale resolution.   the magnetization in the resonant slice of a sample monotonically decays under the action of the fluctuating magnetic field caused by the high frequency thermal vibrations of the cantilevers. in this paper   we use computer simulations to analyze the random mr FM signal in the oscar technique, in particular the sign of the frequency shift of the Cantilever vibrations which is observed in the experiment @xcite. using a computational model for the initial ( regular ) and random ( random ) mrFM signals in the Oscar technique  , we show that the first part of the random signal is due to the effect of the fluctuations in the magnetic moment of the ferromagnetic particle in the resonance slice of the sample during the cyclic adi abatement of the local magnetization induced by the constant amplitude of the vibrational energy of the cotilever tip. in the second part of this paper, we present the qualitative analysis of the spin motion under the influence of the
the discovery of neutrino oscillations provides the only firm evidence for new physics we currently have  @xcite.   this constitutes the most important discovery in particle physics in the last quarter century, implying that the standard model, which correctly accounts for all other experimental data in particleysics, needs revision. to achieve this, it is important not only to investigate the potential of current and upcoming long baseline experiments to determine the neutrinos oscillation parameters, but also to probe for the possible existence of non - standard neutrini interactions, nsi, which are expected in most models of neutrolytic mass generation. in this paper   we review the current status of the constraints for the @xmath21 non -standard neutrinal interactions in view of the larger uncertainties indicated by recent papers.    we combine the laboratory constraints with the restrictions inferred from the analysis of atmospheric neutrinol data. using a simplifying working hypotesis that all nsi parameters other than@xmath22 vanish, we obtain relatively stringent constraints on the nsi interactions for muon neutrines, at the few @x Math23 level, thanks largely to the interplay between the two types of interactions.
we have performed a systematic study of tls from accreting black holes ( nss ) using proprietary and archival rxte / pca data.   we have found that tls are associated with a timing state in which the whole pds is shifted towards high frequencies, and that they are detected at frequencies between  and up to or slightly above the 2 - 40 kev hard state.
recoiling black holes are thought to be important in the evolution of super - massive black holes.   numerical relativity simulations predict that black holes can be kicked out of the galaxy in binary black hole mergers with velocities up to several thousand @xmath2 ( e.g. *????? ). here  , we report the results of the new keck - ii echellette spectrograph and imager ( esi ) long - slit spectrographic observation of the system sbs 1421 + 511, which is a system consisting of a radio quasar at z = 0.276 and a nearby extended source with an off - nuclear agn character. from the sdss spectrum,   the profile of broad emission lines ( bels ) is blue - skewed and the peak velocity of the profile is @x Math13300 @x math2 relative to narrow emission lines . both the blue-skewed profile and the off -nuclear agn characters suggest a super -massive recoilingBlack hole.
the weak energy condition of general relativity requires that there be no negative energy densities.   quantum field theory appears to violate this condition in some cases, such as the standard casimir system of parallel plates, for which there is a negative energy density between the plates. by generalizing the approach of @xcite to local densities, we can precisely cancel the divergences in the calculation in a definite renormalization scheme.
we propose a quantifier for the non - covariance of the schrdinger probability density in local causality.   the quantifier is based on the fact that the probability to find the particle at any region of space is nonvanishing, for the gaussian is nonzero everywhere. by applying this quantifier to the free expansion of a classical gas,   we show that it is possible to consistently evaluate to what extent special relativity is being violated by quantum dynamics.
polar codes were invented by arikan  @xcite as a low - complexity method to achieve the capacity of symmetric binary - input memoryless channels.   the technique that underlies these codes, called polarization, is quite versatile, and has been applied to numerous classical memoryless problems in information theory. however, little is known about the theory of polarization for settings with memory. here   we show that polar coding can be used directly on channels and sources with memory, and that the asymptotic rate of polarization to deterministic distributions is as fast as in the memoryless case. using a proof of polarization that is both simpler than the one given in  ( *???????)* chapter 5, we also show that the error probability guarantees of polar channel and source codes carry over to processes with memories, including well - behaved markov sources and channels.
ultra luminous x - ray sources ( ulxs ) are extragalactic, point - like, off nuclear x -ray sources with observed isotropic x - rays luminosities higher than the eddington luminosity for accretion onto a 10 @xmath0 black hole.   the size and the origin of the black hole ( bh ) black holes ( bhs ) hosted in ulxs are still a matter of debate. here   we analyze the epic - pn and rgs data of all the _ xmm - newton _ observations of x-1 and x-2 in an attempt to use them for determining the chemical abundances in the local source environment. as the sources are faint, the rgs net count rate is quite low ( @x Math21 count s@xmath2 ), and only the last observation reached a reasonable counting statistics in the rgss for the brightest ulx ( x- 1 ), while no useful analysis could be performed on the second ulx(x-2 ). using this approach  , we find that the o and fe abundances inferred from the epic / rgs spectrum of X-1 are consistent with
gamma - ray bursts ( grbs ) arise from relativistic jets with lorentz factor of greater than @xmath10.   the evidence of the jet collimation has been derived by the wave - length - independent achromatic break in the observed afterglow light curve and the jet opening half - angle has been measured in this context for bursts with successfully measured redshifts and jet break times. here  , we discuss the statistical properties of the opening angle distribution as well as the slope of the distribution function using 442 bright batse grbs with good statistics and pseudo redshift from the lag - luminosity relation obtained from the amati relation.
the electron cyclotron resonance ( cr ) and the optical phonon transient time resonance ( opttr ) of gan bulk - like material in moderate electric and magnetic fields are investigated by the monte - carlo method.   we show that overlapping of the two resonances produces specific spectra of thz transmission and reflection, as well as characteristic polarization effects for the gan sample. at moderate electric fields,   the cr is observed in the range of 0.5 tesla to 1.0 teslas, while the opttr is observed only at a range of 1.2 to 2.0tesla. under moderate magnetic fields, both resonances become apparent simultaneously, with the latter being more prominent in the thz - frequency range. during the transition from the high - frequency response of the cr to the low - frequency reaction, the intensity of the opt tr increases with the increase of the magnetic field ; however, it is not affected by the change of the current - field dependence. on the other hand, the temperature of the gas phase decreases with the increasing magnetic field. when the concentration of the ionized impurity is increased, the energy of the oscillations becomes negligible.
the enhancement of the dilepton spectrum in central heavy - ion collisions at cern - sps energies @xcite has generated a great deal of interest in the literature.   various medium effects, such as the dropping vector meson masses and the modification of rho meson spectral function, have been proposed to explain this enhancement. in this contribution   we have extended the walecka model from coupling of nucleons to scalar and vector fields to the coupling of light quarks to these fields, using the ideas of the meson - quark coupling model@xcite. for a system of pseudoscalar mesons, vectors, and axial - vector mesons at temperature @xmath2 and baryon density @x Math3,   the scalar field @x math4 is determined self - consistently from the photon and dilepton spectra obtained from the wa80 collaboration experiments @x maths0 and @x mathematics1, respectively. by taking into account the results of the experimentally measured single photon spectra from the same reactions, we have developed a new model for the reduction of low - mass dileptons to their lowest mass in the initial hot and dense stages of
we show that a fast parallel algorithm can generate growing networks with @xmath4 nodes in @x Math5 steps.   the model has a linear preferential attachment rule and is based on the idea of preferential attachment, which uses knowledge of the existing state of the network to decide where each new node will attach. if the model captures the mechanism for the scale free behavior found in real world networks then perhaps one can conclude that some of the complexity or history dependence of the social, biological or technological system that generated the network is embodied in the network.
the faraday rotation of bismuth - substituted ferrite garnets ( bi : fgs ) grown on ( 100 ) oriented substrates has been studied.   the faraday rotations of the films have been measured at room temperature for photon energies between @xmath0 and @x Math1 ev, corresponding to wavelengths between@xmath2 and @Xmath3 nm.    it is shown that the faradyne rotation changes significantly with the amount of substituted gallium and bistruth. furthermore, the comparison of experimental and theoretical data confirms that the magnetooptic response increases linearly with the bisticuth substitution and decreases almost linearly in the presence of the gallium substitution. also, we report experimental data for the sensitivity of these materials, and find that the sensitivity depends nonlinearly on thegallium substitution, in good agreement with the theoretical model.
the current census of the m31 dwarf spheroidal population is based on the survey of van den bergh ( 1972a, 1974 ) using iiiaj photographic plates taken with the palomar 48-inch schmidt telescope around m31.   this survey has provided a complete areal coverage of the galactic center of m31 at a projected galactocentric distance of @xmath6110 kpc, and it has also revealed that some of the dwarf galaxies in the halo surrounding m31 are located in the outer reaches of its halo. however, the distribution of these galaxies is not as complete as that of the milky way, which has nine low - surface - brightness gas - poor companions ; these are now considered low - luminosity dwarf elliptical galaxies. here  , we discuss the possible reasons for this discrepancy between the two groups of galaxies.
x - ray thomson scattering has been demonstrated to be a reliable and versatile tool for the diagnostics of dense plasmas.   the determination of the plasma properties, such as the plasma density, the plasma temperature, and the plasma composition, requires the knowledge of the density and temperature dependent scattering cross - section. in this paper  , we consider the impact of the densities and temperatures on the scattering signal of cryogenic liquid hydrogen droplets at near solid density ( mass density @xcite ). by averaging the dynamical structure factor ( dsf ) with the electron density profile and the temperature profile,   we obtain the free electron contribution which determines the behaviour of the total electron structure factor at frequencies close to the plasma frequency. through the convolution of the dsf with an appropriately chosen instrumental function, the contributions from free - free, free - bound and bound - bound correlations as proposed by chihara   are taken into account. using the born - mermin approximation, we calculate the contribution of collisions among electrons and ions via the t - matrix and inclusion of dynamical screening.
active galactic nuclei ( agns ) are believed to possess a magnetic reconnection - heated corona above an accretion disk.   synchrotron emission is a key ingredient in the model for the magnetic reconnections of agns and galactic black hole x - ray binaries ( xrbs ). here  , we investigate the expected syn chrotron radiation from a radio - quiet agn corona taking a nearby bright seyfert ic 4329a as an example with the latest observational information @xmath3. using the standard cosmological parameters of @x math3, we study the parameter ranges of magnetic field strength and non - thermal electron fraction which will be constrained by future sub - mm observations.. the results show that the observed values of the magneto - rotational instability and the fraction of non- thermal electrons in a corona are within the limit of the proposed model.
we consider a new type of the inflation which naturally occurs in the loop quantum cosmology @xcite.   this is so called the super - inflationary scenario and is a result of the quantum nature of spacetime in the planck scales. for typical values of the number of quantum numbers,   the inflation takes place in the semi - classical region. to describe the production of the gravitational waves during the super-inflation we include so called inverse volume corrections to the equation for evolution of the tensor modes and then calculate the spectrum of produced gravitational waves using numerical solutions of the einstein equations with quantum corrections. in this paper   we focus on the effect of quantum corrections on the formation of the gravitons on the cosmic microwave background.
the anisotropy of the crystal - liquid interface free energy ( @xmath6 ) reflects differences in the interface structure for different orientations, and may play an essential role in determining the morphology of growing crystals.   we have used equilibrium simulations of the flat bcc - liquid interfaces from the phase - field crystal approach to demonstrate that the free energy of the interface depends not only on the orientation but also on the reduced temperature. using an eight - term kubic harmonic expansion @xcite to represent the orientation dependence in a closed form, we have mapped the orientation and temperature dependence of the interfacial free energy in the pfc model. as in 2d, the dependence of @x math6 on the reduction temperature is consistent with the respective mean field exponent.    we have fitted the results with an expression based on anEight-term kubicular harmonic expansion [ cols= "   <, < ", ] to represent this orientation dependence at several reduced temperatures, and determined the respective wulff shapes, a mathematical construction to which the equilibrium shape, minimizing the interfaces contribution to the cluster free energy for a given volume, tends for large particle sizes.
we have obtained images for 49 seyfert 2 galaxies in 6 ir bands using the vlt at paranal, ntt at la silla and gemini at pachn.   these galaxies were selected from the _ extended 12 @xmath0 m galaxy sample _ @xcite.    we obtained the surface brightness profiles of each galaxy and modeled them to separate the contribution from a nuclear point source and a stellar component ( disk+bulge ) to construct the nuclear spectral energy distributions ( seds ) for each galaxy.. the seds are then fitted using theoretical models of the emission of the dusty torus from@xcite, who solved the radiative transfer problem of a clumpy torus including absorption, emission and scattering. together with our observations   we will use this information to further constrain the sed of our targets and determine the geometrical and physical parameters that govern the ir emission from agns.
a set of equations known as the y - system has been put forward in @xcite to solve the spectrum problem of planar @xmath2 super - yang - mills.   the goal of the present article is to make a new step towards a definite proof of the validity of these equations. at first non - trivial order  , the y-system can be rewritten as a t - system, also know as the hirota equation. up to a change of variables, the t - functions are expected to be related to special line operators of the string worldsheet theory, namely the transfer matrices. by definition, the transfer matrix is the supertrace of the monodromy matrix. if the shifts of the spectral parameter are neglected, the T - system reduces to a character identity that is known to hold ( e.g.@xmath10 ). for large t hooft coupling,   this identity is not always true. here   we show that the results of the proof are consistent with those of the thermodynamic bethe ansatz and the ads / cft correspondence.
the momentum space faddeev equations for three - body scattering in the continuum are solved with high accuracy for the most modern two- and three - nucleon forces.   however, the standard formulation contains a complicated singularity structure within the integral kernel for the free three -Body propagator.. this paper proposes a new formulation of the faddeesh equation in the context of a three - dimensional treatment of the momentum space by introducing a kernel in which only simple poles in one variable can be integrated by standard subtraction techniques. to achieve this,   the angular integrations are carried out along a path in the complex plane, thus avoiding to directly deal with the logarithmic singularities but indirectly imposing conditions on the analytical properties of the two - body force as input.
the onset of slowing down of the dynamics of supercooled liquids is often assumed to be related to changes in the topography of the energy surface or to mode coupling theory ( mct ) singularities.   we show that these crossovers can be understood in a simple physical way in terms of the dynamical properties of effective excitations, or defects, as a progressive crossover from a regime of fast dynamics dense in defect clusters, to one of slow heterogeneous dynamics dominated by isolated localized defects. using a novel real space theoretical framework based on dynamic facilitation of refs.@xcite, we demonstrate that this real space picture explains the observed crossover temperatures, challenges the idea that these Crossovers are related to change in the spatial topography and/or to mct singularities, and accounts for the apparent correlations observed between " landscape" and dynamical parameters.
the optical system is among the most popular physical systems for implementing quantum computation.   this is mainly due to the fact that light quantum states are generally more robust against decoherence than most massive qubit systems, and that the computation programs can be implemented by simple optical elements plus photodetections. in all - optical quantum information processing ( qip ),   the qubits are usually encoded by single - photon polarization states ( other types of photonic qubits can be usually converted to polarization qubits by optical apparatuses ). to complete a universal gate set for quantum computation, an appropriate two - qubit quantum gate from which a controlled - not ( cnot ) gate can be readily constructed @xcite is required.    to implement a photonic two -qubit gate, nonlinear interactions between individual photons are required. here  , we show that the required optical nonlinearity can be achieved directly using a cross - kerr medium that can be described by an interaction hamiltonian of the form @xmath0 @xcide. transforming the modes of the two beams using this hamiltonic will induce a phase shift that depends on the number of photons in the mode.
dna defects can arise from sequence - dependent mechanical inhomogeneity, protein binding, or changes in dna secondary structure.   the defects can also be introduced by protein binding which usually creates a local bending, or modifies the local bending rigidity, or both. in this paper  , we study the effects of two types of defects on the mechanical properties of short dna : one enhances the local flexibility, and the other increases the local rigid bend. to study the effect of the defects, we have used single - molecule manipulation and imaging methods to measure the force response, dna shapes, cyclization probability, and dna end - to - end distance distributions.. the results show that the influence of the hinge and kink defects on these mechanical signals depends on the number of copies of the defect on the dna. for a long dna,   it is necessary to have at least one copy of the bent dna with a line density of at least @xmath2 per base pair ( bp ) ; for a small dna segment, it is needed to have only one or two copies of an excited defect. for shorter dna segments, there are no such requirements.
the spin - orbit interaction is a generic feature in semiconductor quantum dots.   it is usually weak, but it may turn out to be of major importance as, for example, for the spin relaxation, @xcite, or, more positively, for electrical spin manipulation.the anisotropic exchange is a general form of the rotationally symmetric exchange hamiltonian, which is unitarily equivalent to the isotropic exchange Hamiltonian in the weak coupling limit, with the unchanged exchange energy. in the unitary operator providing the change of the basis,   the spin - orbital ground state per dot appears in the linear order and the exchange terms appear in the second order. in this work, we present a detailed assessment of the quantitative reliability of the presented model comparing with the heitler - london ansatz and the first order treatment of the spin-observosome interaction. using a finite magnetic field, we find that the anisotropes are reliable in all important regimes, including weak / strong interdot couplings, zero/finite magnetic field and symmetric / biased dot.
the theory of finite type invariants allows us to interpret many important knot and link invariants in purely combinatorial terms, as functionals on spaces of chord diagrams. for knots,   there is an obvious intersection graph associated with these diagrams, first studied ( in this context ) by chmutov, duzhin and lando @xcite.   the goal of this paper is to introduce a reasonable definition of the intersection graph for chord diagrams associated with string links. as evidence that this is the " right " definition  , we use these intersection graphs to construct weight systems for string links, and show that these weight systems are related to ( though weaker than ) the weight systems arising from the conway and homfly polynomials. in future work   we will show that in some cases the intersection Graph contains all the relevant information in the string link chord diagram, and that it can be used to give a new interpretation of milnor s homotopy invariants.
we present a generalization of the monte - carlo cascade code developed in @xcite to non - negligible magnetic fields and consider the angle dependent synchrotron emission from the cascades.   we confirm that for the objects cen  a and ngc  1275 the synchrodes are negligible for those parameters used in @xmathite. in order to investigate the effect of the magnetic field and its degeneracy, we investigate the effects of the decay rate and the degeneracy of the colloidal phase of the radio galaxies. using a combination of numerical results and theoretical calculations  , we show that the decay rates of the bl lacertae objects ( bl lac objects ) are strongly affected by the degenerate magnetic field but not by the age of the objects. with respect to the background light,   the degenerative effects are most pronounced for the low - frequency peaked bl lac object ( lbl ) and the intermediate bl Lac object ( ibl ). on the other hand, the degenerated lbl and ibl are more sensitive to the degenerating magnetic field than the non - degenerated ibl.
the entropy production rate ( ep ) has been highlighted as a promising determinant of self - organized ordered structures in non - equilibrium thermodynamics.   the minimum ep ( minep ) principle has been extended to describe various structures self -organized in nonlinear dissipative systems ; however, examples of " maximizing " ep have been found in various non - equilibriated systems, suggesting the possibility of antithetical " maximum ep ( maxep ) principle. here  , we show that the maxep branch of the minep principle is stable when the system is " flux - driven," i.e. the heat flux driving the non -ilibrium system is the parameter that controls the operation mode ; the opposite is a " force - driven" system, in which a thermodynamic force ( for instance, a temperature difference between two boundaries connected to heat baths ) is the control parameter. by comparing the total ep of _ bifurcated _ operation points in ( quasi ) stationary states, we find that the maximum ep state is the operating mode with the largest ep among possible modes of ( quasi)stationary states.
the organization of membrane proteins into complexes and their effect on membrane shape is thought to be driven by a universal interaction force arising from membrane deformations.   we describe a specialized model system consisting of membrane - adhering colloidal particles adhered to single - component giant unilamellar vesicles ( guvs ), allowing us to study the effect of a single adhesive colloidal particle on the local membrane shape using confocal microscopy. in this model system, we find that the particle is either fully wrapped by the membrane or not wrapped at all, depending on the adhesion strength. as a proof of principle, we measure the interaction potential for particles in these two states and find that only wrapped particles show a reversible attraction, which implies that the attraction is purely caused by the deformation of the lipid membrane. monte carlo simulations of the bending - mediated interaction between wrapped particles   result in an interaction potential that quantitatively agrees with the experimental result. since these simulations do not contain any absolute length scale, we conclude that the measured attraction caused by lipid membranes deformations is scale - independent. our combined model system and simulations   therefore quantitatively describe the interactions of any membrane - deforming object
the disciplined software engineering relies on software architectures to describe systems.   dynamic reconfiguration is when the evolution of the software systems is performed at runtime with no service disruption. among many existing architecture description languages ( adls ), only few allow modeling dynamic reconfigurements. in this work,   we investigate the current state of the art in the literature and illustrate how four well - known adls ( @xmath0-adl, acme, c2 sadl, dynamic wright, and c2sadl ) support dynamic reconfigured software systems. by using a tcp / ip stack system as an example, we show that all four adls support dynamic Reconfiguration. however, there is no consensus about how the software architecture should be addressed at the architecture level. for example, does regular syntax for dynamic architectures allow the same reconfigurations as specific language constructs? should the state of components and connectors be taken into account at the architectural level?   if so, what language constructs should be provided for dynamic reconforaments?
comodule algebras provide a natural noncommutative generalisation of spaces equipped with group actions.   the aim of this article is to establish a viable concept of locality of comodule Algebra and analyse its relationship with principality.. we analyse the notion of locality we use herein results from decomposing algebraes into " pieces ", meaning expressing them as multiple fibre products.  in particular, we consider the concept of a piecewise trivial Comodule algebra @xmath0 which is covered by " pieces" and find that it is principal if and only if all the pieces are smash products. using hopf - galois theory and analytic tools coming with @x Math6-alge bras, we show that the data of a covering by pieces can be equivalently encoded into the total space of a set of locally trivial compact principal bundles given by a finite family of algebra surjections along the fibres of the quotient@xmath6-analgeses. on the other hand, when the coverings are not covered by pieces, then they are not principal.
communication is a recently developed communication paradigm whose communication process involves " transmission and reception of information encoded in molecules" ( @xcite ).   it is born in the study of nano - scale communication in nanonetworks where the applicability of classical electromagnetic communication is limited by several constraints and a novel solution is called for. among the various proposed system blue maps for molecular communication, a specific class of system called the " diffusion - based molecular system " draws lots of interest due to the universality of _ mass transport phenomena _ in molecular communication. however, two important things are still lacking : first, an unified channel model for diffusion -based molecular communication is not yet established ; that is, the existing works on information - theoretic analysis tend to be system - dependent and give their own capacity analysis. moreover, no mathematical foundations have been put down for information theory in this field. in particular, the channel coding theorem is not proven for diffusion-based systems. here  , we review the current state - of - the - art in the field of information theory about the information rate capacity of these systems.
lyman - alpha ( ly@xmath0 ) is the strongest emission line in the universe and is frequently used to study the highest redshifts.   however, the resonant nature of the Ly@x Math0line complicates studies of galaxies as the observed spectra do not directly connect to intrinsic properties of the gas. here  , we show that this problem can be overcome by using a simple, multiphase model of resonant radiative transfer ( rt ) in which the resonance frequency of the emitted photon is shifted slightly depending on the temperature and velocity of the surrounding gas. under certain circumstances,   the rt process is more sensitive to the size of the clump of hydrogen atoms in the medium than in the homogeneous one.    we find that when the clumping is very small, the rr of the scattering cross section of the line is much smaller than in a homogeneous medium and that the transition from homogeneous to clumpy mode is caused by the existence of bound - betw - clumpy clusters of hydrogen atom clusters at the edge of the light - center line. for large - scale quasar outflows and bal regions around galaxy - like regions,
the high cost of ruthenia ( ruo@xmath0 ) electrodes is a major hurdle to the commercial deployment of energy - storage devices based on pseudocapacitive oxides.   we have developed a quantum continuum model of the solid  solution interface of an electrified electrode covered by adsorbed protons that combines a quantum - mechanical description of the electrode with a continuum representation of the surrounding electrolyte. using this model, we build an exhaustive database of solvated equilibrium structures for protons adsorption at the surface of the substrate and carry out large - scale monte carlo simulations under applied voltage for predicting the charge  voltage response and electrical performance of the electrolyte at finite temperature. in particular, we use the self - consistent continuum solvation method to simulate the electrochemical response of the oxide  electrolyte interface during the intercalation process between the charged and neutral states of rutshenia. from these calculations, we construct a comprehensive model of both the experimental bulk crystal structure and the solvent - dependent evolution of the ionic   electrolyte interactions at the interface of the electrodes, which is then used to predict the electrochemically active state of the interface.
in this paper we present the four - loop corrections to the decoupling constant for the light quark masses, which supplements the five - loop result for @xmath8  @xcite.   the calculations are performed with the help of a formalism which allows for an effective calculation of the@xmath5-loop decoupled constants with the use of @x math5- loops vacuum integrals. in the following sections   we discuss the formulae which are relevant for the computation of the quark mass decouplings constant and its renormalization to arrive at @x Math0.    we also derive a low - energy theorem to derive, from the results of these calculations, the effective higgs - fermion coupling constant to five - Loop order.
we recently proposed a new caching approach to reduce network congestion in content delivery networks, called simultaneous coded - multicasting opportunities.   this approach is based on the assumption that the network operates in two different phases : a content placement phase and a content delivery phase. in the placement phase,   content is placed in order to allow the central server to satisfy the requests of several users with different demands with a single stream of multicast streams generated by coding across the different files requested by the users. since the content placement is performed before the actual user demands are known, it has to be designed carefully such that these coded - Multicast opportunities are available simultaneously for all possible requests. in  @xcite, we show that this simultaneous coded-multicast gain can significantly reduce network traffic during peak hours. however, the assumption of a centrally coordinated placement phase was helpful to establish the new cache approach proposed in @xcite. here, we present a new cache algorithm that creates simultaneouscoded - multicast opportunities without coordination in the placements phase. as a result, the proposed algorithm is able to operate in both the placement and the delivery phases at the same time. unlike the conventional caching approach, which is effective whenever the
the origin of cosmic rays ( crs ) in the interstellar space is still a matter of debate.   we use data from the _ fermi - large area telescope ( lat ) to investigate the @xmath0-ray emissivity of atomic gas in the second galactic quadrant, at ~7  pc from the solar system, and to derive the density of the interstellar medium ( ism ) column densities using the 21 cm line of atomic hydrogen, @x Math3, and the 2.6 mm line of carbon monoxide, co. the results are compared with the predictions by galprop, a widely used code for cr propagation, and are consistent with an independent study of lat measurements at intermediate galactic latitudes in the third quadrant @xcite.
analysis of hadronic particle production in relativistic nuclear collisions offers an opportunity to explore the mechanisms of quark confinement at the time of final state ( color charge ) plasma ( qgp ) freeze - out.   we present here a progress report of such ongoing analysis of the recent and forthcoming experimental study of the pb   pb collisions at 158 a gev @xcite, which follows on our now complete analysis of s  au / w / pb collision systems @xmath2 mev@xcite. among several proposed approaches to search for and study the deconfinement, our work relies on the idea of strangeness flavor enhancement, and the associated enhancement of ( strange ) antibaryon formation @xaite.. this signature can be combined, in the present analysis, with the study of global particle abundance which represents the entropy contents of the deconfined phase @xfite.
gdel s completeness theorem is one of the most important theorems in logic.   it is concerned with a duality ( in a naive sense ) between proofs and models : for every proposition @xmath0,   _ either@xmath4or@x math5. however, girard s ludics ( @xcite ) is a more interactive account of completeness, which corresponds to a polarized fragment of multiplicative additive linear logic, which is too weak to be a stand - alone logical system. as a consequence  , one does not really observe an opposition between finite proofs and infinite models, since one can always assume that the countermodel @x Math2 is finite ( related to the finite model property for @x maths15 ). indeed, proving the above completeness is easy once _ internal completeness _ is taken into account.
Drill holes in a superconductor to improve its chemical and thermal properties has been proposed.   the effect of the arrangement of the holes on the magnetization drop of drilled samples is investigated by studying the current distribution and the interaction among the influence regions of the hole patterns. for that purpose  , we develop an algorithm based on the bean model and on an observation made by campbell and evetts to calculate the magnetic field in the critical state for an infinitely long drilled sample with an arbitrary cross section. using the algorithm, we find that the magnetizations of samples with either a semi - infinite or a circular cross section and holes disposed on a lattice pattern increase with the number of holes as a function of their relative positions. when the holes are placed in different positions in the lattice,   these increases are more pronounced in the center than in the outermost region of the lattices. at the same time, the current stream lines near the holes abruptly change their direction along discontinuity lines and circle the hole in a region that extends far beyond the hole itself. this effect is enhanced in thin films of ybco thin films, as the magnetic flux density displays sharp peaks at the discontinuous lines.
in correlation analysis of binned data the quantity of interest is the covariance of observable @xmath0 between arbitrary bins.   the goal of this paper is to calculate the statistical error in this quantity by following and extending the error propagation and error reduction method of reid and trainor   reid - trainor for the calculation of the reference for ultra - relativistic heavy - ion collisions such as those measured by the star experiment, where the number of sub - atomic particles produced and detected for each collision is calculated by averaging product@xmath11 over all collision events in the event collection. a practical mixed - event method for calculating the reference   is presented in which random, event - wise fluctuations ( noise ) in the quantities @x Math17, @x maths18 and @x math11 cancel in the covariances, reducing the errors.. the choice of the references and the event - mixing method strongly affects the statistical errors in the final correlation measurement.    the consequences of these decision - making choices are quantified using the statistical noise reduction method developed by reid-trainor.
we have recently combined the _ ab initio _ no - core shell model ( ncsm ) and the resonating - group method ( rgm ) into a new many - body approach   @xcite ( _ abinitio _ nc smm / rgm, n = 4 ) capable of treating bound and scattering states of light nuclei in a unified formalism, starting from fundamental inter - nucleon interactions.   we have applied the new approach to the calculations of the @xmath15-@xmath16h, @x Math15-#17he, #18be, and #19-#20he scattering processes, using sufficiently large @x math25 harmonic oscillator ( ho ) excitations to guarantee convergence of the calculation with the ho basis expansion of both the cluster wave functions and the localized rgm integration kernels. for each of these processes,   the results show that the rgm can be used to study the ground state of the excited states of the lightest nuclei, as well as the parafunctionalization of the low - lying excited states, and the parity inversion of the electron ground state, using realistic @x maths11 potentials.
the application of the one - point two - group feynman - alpha formulas to fast fission and thermal detections in accelerator - driven systems ( ads ) is discussed.   the results of the analysis of the variance - to - mean ratio in the case of a pulsed neutron source with a pulsing pulse shape and pulsing manner are compared with those of the same source with delayed neutron precursors, and with the use of scintillator - based detection technologies. for the first time, the influence of the energy - dependent behavior of neutron counting on the performance of the formula @xmath2-@xmath3 is taken into account in the derivation of the general case of one - points two - groups feyn mann - alpha equations. when the system is near - critical, the deviations of the relative variance from unity between the average number of counts during a detection time and the fluctuations around this value, expressed by the variance @x math2-~q^2, are higher than unity, the deviation from unity is considered as a branching process. at the same time, both the prompt neutron decay constant and the asymptotic value of the decay constant are found to be
the hoop conjecture states that for a spacelike hypersurface, a black hole horizon exists if and only if the mass @xmath1 of the system gets compacted into the interior of a closed surface s whose circumference ( hoop ) @x Math2 satisfies the condition @x maths3.   the hoop conjecture is meaningful to confirm not only because it is interesting theoretically, but also it can be a useful tool to test the formation of a blackhole in numerical simulations. in this paper, we investigate the test of the hoop conjectures using initial data of einstein s equation. as the initial data depends on two parameters : one is a separation @x math6 of two black holes and the other is a momentum @xMath7 of each black hole, we find that the apparent horizon formation occurs if the energy of the systems is well concentrated in a region enclosed by both black holes.    we also find that there is a necessary and sufficient condition for the existence of an apparent horizon.
we study the effects of the ambient solar wind on the shape of a shock generated by a fast coronal mass ejection ( cme ) originating from an active region of the solar corona on 2011  march  7.   we use in  situ data from the stereo mission @xcite and heliospheric images from the cor2-a telescope to reconstruct the shock shape from the data, and we examine whether mhd models of the inner heliosphere can successfully reproduce the inferred shape. for the first cme, a fast cme originating from active region ar1166, which is just to the east of a coronal hole, we find that the shock deformation caused by the high speed wind from the sun is uneven, with the western half of the shock propagating outwards through high speed winds, ultimately hitting stereo - a on march  9, while the eastern half propagates outwards into the interplanetary medium through slow speed wind, ultimately reaching earth a day later on March  10.see research article http://www.biomedcentral.com/1471-7007/9/10/826.
we have monitored the flux density of Sagittarius a@xmath0 at 22.2 ghz from feb.   2013 to aug. 2014 with a sub - array of japanese vlbi network ( jvn ) ( @xcite ) in order to explore any change caused by the small gas cloud, called  g2 ", that is, a gas cloud or a star with dusty envelop around the galactic center super massive black hole ( gcbh ). during the observation period,   the observed flux density was 1.5 times higher than the measured value for the previous 3 years with vla and there was no flare with over 100 % amplitude in the monitor ( @xaite ).    the data were transmitted via internet, immediately after every observation finishes, to the isas where a software cross correlator which has been developed by nict ( kondo et al., 2004 ) was used to detect the initial raising phase by ourselves and to alert world - wide community to observe the phenomenon.
the tight correlation between the mass of a supermassive black hole and the properties of its host galaxy spheroid component is now well established in the local universe, indicating a coeval growth history of galaxies and their central black holes.   however, the detailed role of this correlation for our understanding of galaxy evolution and black hole growth is still an open question. in (   * hereafter sw11 ) we presented a common framework, based on the bivariate distribution function of black hole mass and sp heroid property, to investigate and model the luminosity bias and other selection biases on the @xmath0-bulge relations. here   we present a quantitative assessment of, and a correction procedure for sample selection effects on observations of the@xmath1bulge relation using broad line active galactic nuclei ( agn ) samples. while the results suggest a trend of positive evolution at high redshifts, the interpretation of the observed correlations in terms of evolution or non - evolution is challenging due to the sampling selection effects. as a result  , we have developed a simple and robust correction procedure to account for these effects.see research article http://www.biomedcentral.com/1471-7007/
the opera experiment is a hybrid detector that uses the long - baseline ( l=730 km ) cngs neutrino beam from cern to lngs, the largest underground physics laboratory in the world.   the main scientific task of the experiment is the first direct detection of the @xmath0 appearance, an important missing tile in the oscillation scenario  @xcite. for this purpose,   a large mass target made of 1 mm thick lead plates ( target mass and absorber material ) interspaced with thin nuclear emulsion films ( high - accuracy tracking devices ) is used as a target.    the detector is equipped with an automatic machine ( the brick manipulator system, bms ) that allows the online removal of bricks from the detector. during the scanning process   changeable sheets are glued to the downstream face of each brick and can be removed without opening the brick.the results of the experiments are compared with those of the electronic detectors at cern and nagoya.
we study the effect of attractive three - body interactions on the ground state energy of a one - dimensional bose gas, @xcite, in the limit of large number of particles.   we employ an hartree approximation to study the problem in the general case of @xmath0-body contact attractive interactions, with the constraint that the energy per particle is finite. for this value,   the solution of the gross - pitaevskii equation admits a localized soliton wave - function, the so - called _ bright soliton _   soliton, which is in agreement with the thermodynamic limit of the attractive one - dimension bose gases @xcites.    the results show that the surface energy of the hot soliton can be tuned to be zero by changing the sign of the external trapping potential.
synchronization is a dynamical process where two or more interacting oscillatory systems end up with identical movement.   synchronization has become a basic concept in nonlinear and complex systems, such as mechanical instruments, electric power systems, lasers, and electrical devices. here   we show that the cross - gradient hamiltonian structure obtained in @xcite naturally appears in the asymptotic reduction of the original hamiltonia structure of newton s equations of motion for the coupled pendula, which is characterized by the existence of breathers ( time - periodic solutions localized in space ), which are continuous families of their energy parameter. depending on the parameters of the lifetimes of the breathers,   they can be considered as discrete nonlinear schrdinger equations with symmetries and conserved quantities. when the breathing parameters are taken into account, it is shown that the real - valued hamiltonians exist both in finite and infinite chains of coupled nonlinear oscillators.
the choice of collateral currency does significantly affect the price of derivatives.   this is because non - zero basis spread in ccs ( cross currency swap ) is nothing but the difference of the relative funding cost between the two currencies, which then affects the funding cost of a deal collateralized by a foreign currency. in order to mitigate the problem, isda ( international swaps and derivatives association ) is planning to release scsa ( standard credit support annex ) in 2012. for a trade involving only a single currency within the above g5 currency silo,   the discounting rate is simply the overnight index swap ( ois ) rate of the same currency. if a contracting party chooses different currency to post, the collateral rate will be adjusted in such a way that it gives the same economic effects as the standard case. in this note  , we discuss the issues of the usd - silo valuation framework.
abstractin recent years, several papers have reported the repeated detection of extremely violent variability events in some blazars, with amplitudes @xmath10 mag in a few tens of minutes.   these phenomena are thought to be caused by relativistic beaming of the accretion - disk ( ad ), which is one of the most important mechanisms for the generation of energy in active galactic nuclei ( agns ). if confirmed, these extremely violent phenomena would require a complete reassessment of the mechanisms which are responsible for the energy generation in agns. here  , we review the current knowledge on the origin of the observed microvariability in many classes of agns, and discuss the implications of these findings for the canonical model of agn energy generation.
we investigate nambu   jona - lasinio ( njl ) model with quark content which is one of the most successful effective models of qcd in the non - perturbative region.   we have used an iteration scheme of solution of schwinger - dayson equations with fermion bilocal source @xcite to formulate mean - field expansion(mfe ) for njl model. using the same iterative scheme, we have considered equations for green functions of nlj model in mfe up to third order. from the results of previous investigations,   the solutions of multi - quark equations will provide us almost exhaustive information about the structure of hadrons.
empirical analysis of high - frequency financial data has been attracting significant interest among physicists as well as economists during a decade. in this article   we focus on the number of tick quotes in foreign currency rates ( usd / jpy ) and investigate the statistical properties of them by utilizing the power spectrum technique.   it is found that the averaged power spectrum density ( psd ) has some peaks at about 2 minutes ( the peak frequency depends on the currency markets ). to explain this phenomena a simple agent model based on double - threshold noisy device ( sato 2004 ) is proposed. from a result of numerical simulations of the model it is finds that the high periodicity of the number, i.e., the ticks per minute, may be caused by common exogenous periodical information.
the time dependent non - equilibrium radiation diffusion problem for finite size systems in both planar and spherical geometry is solved using the numerical finite difference method.   the results are compared with benchmark results for the heat conduction approximation @xcite,@xcite or the diffusion approximations @xaite, @xco2,@xcite. a detailed analytical solution for the finite planar slab / shell width and parameter values relevant to practical problems   is obtained by means of the separation of variables and laplace transform method or the eigenfunction expansion method. as the radiative transfer codes are meant to handle an arbitrary temperature dependence of the material properties, the obtained solutions serve as a useful test problem.
extended theories of gravity are alternative theories of gravitational interaction developed from the exact starting points investigated first by einstein and hilbert and aimed to explain galactic and extragalactic dynamics without introducing dark matter.   they are aimed to address conceptual and experimental problems recently emerged in astrophysics and cosmology from the observations of the solar system, binary pulsars, spiral galaxies, clusters of galaxies and the large - scale structure of the universe. for at least one of them,   called s2, there are some observational indications that its orbit maybe deviates from the keplerian case due to relativistic precession. here  , we fitted the ntt / vlt astrometric observations of s2 star to the yukawa - like corrections of the gravitational inverse square law obtained in the framework of @xmath0 gravity and show that the results are consistent with the predictions of the extended theory of gravity.
the chern - simons formulation of three dimensional ( 3d ) quantum gravity is discussed in this talk.   it is shown that the chern-simons approach to 3d quantum gravity can be used to study the role of non - commutative geometry in describing quantum scattering processes in 3d gravity, and that the braid group may play an important role in this context. as a result,   the main focus of this talk is on the use of the spin foam approach to describe quantum scattering at the quantum level, which is one of the most directly useful lessons learned from the work on 3d hyperbolic geometry.
we study spin effects resulting from the interface scattering under non - equilibrium conditions appearing when an electron current flows in a 2d system composed of an electron gas with spin - orbit interaction ( soi ) and normal ( n ) 2d electron gas without soi, lying in one plane.   the main purpose is to find out whether the spin currents, which exist in the soi region due to the coupling between spin and orbital degrees of freedom, penetrate into the n region and how the spin density is distributed there under the non - equilibration conditions when an electrons can pass through the boundary of the Soi region. for this purpose,   two main effects are found : ( 1 ) the electron current parallel to the interface leads to the spin accumulation near the interface and changes in the edge spin current ; ( 2 ) the edge Spin current augmentation is proportional to the accumulated spin density. both these spin currents penetrate deep into the normal region and have considerable polarization.
the extremely red objects ( eros ) and the ly@xmath1 blobs are two of the most enigmatic types of high redshift galaxy.   they are characterized by 100 kpc scale low surface brightness nebulae, with total luminosities of up to 100 000 kpc at redshift @xmath6. in this paper   we present a detailed study of a _ radio quiet_   ly@Xmath1 blob that contains two compact eros. using near - ir and ground - based imaging, we show that the object is a dense cluster of lyman - limit qso absorption - line systems containing an unresolved, luminous, extremely red source lying within a superwinded, compact proto - cluster environment. from these observations  , we conclude that this object is probably a pair of young merging elliptical galaxies, though a compact dusty starburst model is hard to completely exclude. for the nebula surrounding them, we find that it is either photoionized by an agn or shock excited by the energy of gravitational infall or of a super winds.
the discovery of @xmath0al in the interstellar medium by the heao-3 satellite has raised the interest on potential diagnostics of nucleosynthesis in several scenarios.   we have computed a series of hydrodynamical models of nova outbursts for several white dwarf masses and accretion rates, adopting updated initial calculations based on onemg white dwarf core mass and accreting rate. using these models, we analyse the influence of the different prescriptions available on the final @x Math0al yields in the ejecta of classical novae.. the results show that the most important role played by novae is in the production of long - lived radioactive nuclei, such as@xmath5na and @x math0al, which are not produced by low  mass agb stars or supernovae but are produced by solar or cno - enhanced envelopes. however, for models with an accretion rate of t@xMath6 k, the majority of the @x maths0al is produced by high  mass white dwarf stars, from which the origin of the 1809 kev emission can be attributed only to novae ( ~2.5 m@x1
the galactic bulge region is a rich source of compact x - ray sources.   the bepposax wide field camera ( wfc ) has identified 17 new burst sources in the bulge area since 2000. among them are several sources with low peak luminosities, some of which have been observed to have transient outbursts and others have recurrence times of about 160 and 180 days. at the time of observation,   all but one of the sources had a peak flux of only 2.2 mcrab. during the first two years of this monitoring program  , we have observed 9 transients from these sources that have a peak luminosity of about 1 - 20 mcrabs per minute. while the sources have been identified, more sensitive observations and identifications are needed to confirm their identity.
the muon bundle data from the bust detector ( baksan valley, north caucuses, russia ) are used to study the alignment of high energy muons in the extensive air showers ( eas ) cascade at high altitudes.   the results of the search for aligned events among the muon groups observed in the bust data are presented. a simplified model of particle coplanar generation ( pcgm ) in the first interaction of a primary particle with an air nucleus has been used to analyze the alignment phenomena. by means of monte carlo simulations   it is shown that the influence of magnetic field on alignment of muons is strong and it doubles the background fraction of aligned muon bundles caused by the cascade development.
we study the transport of the quantum spin - hall states and the persistent currents of an armchair ring with spin - orbit interaction ( soi ) in a graphene lattice.   the ring is a graphene ribbon with armchair edges, which has no edge state in the absence of soi. by changing the parameters of the lattice model, it is found that the edge persistent charge current ( pcc ) is small, while the edge spins are very strong. for a narrow ribbon, the edge states from opposite sides couple with each other, which may open an energy gap and reduce the persistently currents. for both narrow and broad ribbons,   these effects are not observed.    we also find that the ripples in the periodic saw - tooth curves of the persistent Currents are due to the rashba coupling.
limit cycle oscillations ( lcos ) are encountered in a number of real engineering applications including aircraft, machine tools and automotive disk brakes.   lcos often limit the performance and can also endanger the safety of operation using the van der pol  duffing ( vdpd ) oscillator, which is a paradigmatic model for the description of self - excited oscillations. in this paper,   the nonlinear tuned vibration absorber ( nltva ) is proposed as a novel strategy for lco suppression. following references @xcite, the linear spring coefficient of the nltvae is determined to maximize the stable region of the trivial solution of the host system. after determining the optimal values for the linear parameters of the Nltva, stability analysis of the coupled system   is performed to determine the bifurcation behavior of the system at the loss of stability ; the results show that the equilibrium point of the oscillator s mass, damping and the coefficients of the linear and cubic springs lose stability through either a supercritical or a subcritical hopf bifurscation. by virtue of its nonlinear nature, the ntva is designed to ensure supercritical behavior and to mitigate
the adsorption of polyelectrolytes ( charged polymers ) in solution is treated as an extension of neutral polymer theories.   we present two coupled differential equations derived from the total free energy of the system, one based on the electrostatic potential and the other on the concentration profiles of the polymer and the small ions. for a single charged surface held at a constant potential,   the results are compared to exact numerical solutions, and to experiments measuring the amount of polymer adsorbed on the surface.
the deep - field survey of the universe ( dls ) is a large, uniform dataset of images and catalogs that will be used to study the evolution of mass clustering over cosmic time using weak gravitational lensing.   the dls will also provide constraints on cosmological parameters which are complementary to the observed anisotropies in the cosmic microwave background and to the expansion history of the cosmos as probed by type ia supernovae. for each of these applications,   we have chosen 4 - 5 different filters with a wavelength baseline sufficient to derive photometric redshifts between @xmath6 and @x Math7, and at least 5 independent, well - separated fields, selected without regard to already - known structures, to cover an area of sky sufficient to include the largest structures expected to be observed.. the dl data will be available online at http://www.astrodata.org/ls/dls/.
we study the concurrence of entanglement between two single - level quantum dots tunnel - coupled to majorana bound states ( mbss ) in a superconducting hybrid device.   we find that the quantum states of the two quantum dots are fully entangled in the long - distance limit, i.e., both dots are perfectly disentangled. for a grounded superconductor, where the charging energy is negligible, this is not the case, and one finds that precisely the opposite statement holds true in the short- and long - range limits. since the quantum state of the quantum dots is described by self - adjoint operators, which anticommute with each other, it is unlikely that they are also fully entangled.
the geometric scaling property of deep - inelastic scattering ( dis ) on a proton is one of the most intringuing empirical observations about the kinematical properties of dis.   the question we want to address is whether the observed geometric scaling can be explained in terms of qcd evolution equations describing saturation of parton ( mainly gluon ) densities at high rapidity. from a mathematical point of view, the balitsky - kovchegov ( bk ) equation can be related to an " universality class " of nonlinear equations for which characteristic properties can be rigorously derived. in the case of the bk equation and also for some extensions beyond bk  , this generic feature is the formation of _ traveling wave _ patterns when the energy increases. as we shall see, traveling waves are intimately related to geometric scaling.
we explore the constraints from future galaxy weak lensing ( cosmic shear ) surveys combined with the current cosmic microwave background ( cmb ) results on cosmological parameters, particularly the running of the scalar spectral index.   we use statistical inference theory to predict how well these surveys will be able to improve the errors on @xmath4 and@xmath0, using data from the cosmic background imager ( cbi ), the arcminute cosmology bolometer array receiver ( acbar ), and the two degree field galaxy redshift survey ( 2dfgrs ). in combination with the cmb, this is expected to give an error of about 0.05 error on both scales, with a scale invariant model fitting the data at 1.3 for the first acoustic peak by the _ wilkinson microwave anisotropy probe_ ( _ wmap  ).
we study systems of globally coupled piecewise fractional linear maps on the interval @xmath9 $ ], where each individual map has a smooth invariant density. for small coupling strength,   we show that the nonlinear self - consistent perron - frobenius operator ( pfo ) of the system undergoes a supercritical pitchfork bifurcation as the coupling strength increases.   at the same time, all corresponding finite - size systems have unique absolutely continuous invariant probability measures on their state space, and exhibit exponential decay of correlations under this measure. in the case of larger coupling strength  , however, we find that the pfo behaves in a more stable way, and the mixing of the invariant probabilities of the systems becomes more complex with increasing coupling strength.
the magnetic field of the milky way galaxy is the only galactic magnetic field that can be studied over 5 orders of magnitude, on length scales less than a parcsec to several kiloparsec.   the structure of this magnetic field is revealed by different observing techniques that are usually sensitive to either the line - of - sight component of the magnetic field ( faraday rotation, zeeman splitting ), or the component of its magnetic field perpendicular to the line of sight ( stellar polarization, polarization of radio synchrotron emission ). in this work, we present a statistical description of the variance as a function of angular distance from the center of the Milky Way to the edge of the universe using the raman resonance structure function ( rm structure function ) @xmath5. for the large - scale magnetic field,   an electron density distribution must be assumed as an assumption that is largely unconstrained by current observations, as significant angle changes can occur in an ionized region that can not be detected by its thermal emission. here  , we propose a model of the distribution of the electron density along the lines of sight based on the results of simulations of the polarization of polarized emission from pulsars and distant active galactic
the origin of stellar clusters is a long - standing mystery.   the question of the physical origin of such clusters remains largely a mystery, in part due to the fact that cluster formation is a complex physical process that is intimately linked to the process of star formation, for which there is as yet no complete theory. however, the development of a theoretical understanding of star and cluster formation depends on first acquiring detailed empirical knowledge of these phenomena. during the past two decades  , it has become possible to detect, survey and systematically study the extremely young embedded stellar clusters within nearby molecular clouds using optical- and infrared - optimized telescopes. here   i review the empirical knowledge that is setting the stage for the eventual development of an empirical theory of the origin of embedded - cluster populations and the nature of the gaseous cloud cores in which they form.
the grb 060505 ( @xmath3 = 0.0889 ) burst was observed on utc 2006 may 5 by the swift burst alert telescope ( bat ).   it has a burst length of ~24 s, but notably lacks evidence of an accompanying supernova. here   we investigate the host properties of the grb progenitor region and propose a new class of long - duration high - energy bursts ( grbs ) with no associated supernovae based on our current understanding of the progenitors of grb-060505. in this study, we find that the host galaxy of gr b 060 505 is an sbc spiral, which is unusual for a long -duration grb event. using a combination of time - resolved spectroscopy and pulsar imaging, we show that the burst region is dominated by young massive stars in a low - metallicity star - forming environment, consistent with a compact - object merger or core - collapse progenitator scenario. however, we also find that there is no evidence of a supernova at the burst site when compared with the other regions of the host galaxies. to test the existence of a novel class of grbs
eclipsing binaries have historically contributed a wealth to stellar astrophysics.   the _ kepler _ mission @xcite and its unprecedented precise photometry of @xmath0 stars, has allowed us to create a catalog of 2605 eclipsing binaries ( hereafter ebs ) in the field of the_ kepler_ field.    this catalog is rich in interesting objects for individual study and also presents a large sample of ebs for statistical analysis. in studying this sample, we can attempt to determine the occurrence rate of eb, circumbinary planets, and multiple star systems. using eclipse times, we will examine the effects of third bodies, apsidal motion, and gravitational quadrupole coupling on the timing of these eclipses. by measuring the exact time of each eclipse for a particular binary and comparing it to the calculated time from the linear ephemeris, we are able to create an eclipse timing variation curve ( ` eclipse timing variations'; sometimes also referred to as an o - c diagram ) that can be used to study the dynamical effects occurring in the system over time. here  , we provide eclipse times for all 2605 ebs in the catalog, and compare the observed rates of
a large amount of astronomical data suggests that the @xmath0 newtonian gravity from the baryonic material in galaxies fails to explain the large accelerations implied by motions in spiral and elliptical galaxies.   a recent breakthrough by bekenstein ( 2004 ) transforms the empirical mond formula to a falsifiable theory with respectable theoretical underpinnings comparable almost to the rival dark matter theory. here   we examine various aspects of the mond theory after outlining cosmology and lensing in the relativistic mond, which follow the standard general relativity formulation.
we investigate the gauge - matter - gravity system where the gravitons propagate in ( 4+n ) dimensional spacetime while the gauge and matter fields live in the normal four dimensional world.   the theory is renormalizable by adding a higher derivative term for each field in the standard model ( sm ) to the lagrangian at the beginning of the renormalization so that the quantum corrections induced by the one - loop gravitational corrections induce a new higher derivatives term with mass dimension six, which is the term needed in the lee - wick sm ( lwsm ). since gravity does exist in nature, it provides a natural mechanism to the emergence of this exotic particle.
the geometric phase ( gp ), first discovered by berry @xcite for adiabatic cyclic changes of pure quantum states, has been generalized to a wide range of contexts, such as non - abelian, non - cyclic, and mixed state evolution.   the orange slice shaped path, formed by connecting two antipodal points on the bloch sphere along two different semi - great circles, is associated with vanishing dynamical phase, which allows for direct measurement of gp. here  , we generalize the concept of orange slice shape to the non-abelian gp in non - adiabsidic evolution @xxcite. using a pair of pulsed interactions in a cyclic chain of four coupled qubits, we show that the resulting non - monovalent geometric phase can be used for universal non - adsorbed holonomic single - qubit gates.
blazars are the most extreme and powerful sources among active galactic nuclei ( agns ), whose broadband emission is mainly dominated by non - thermal components produced in a relativistic jet pointing toward us @xcite.   the origin of the seed photons for the inverse compton ( ic ) scattering in blazars is an open issue, which include the synchrotron photons ( ssc process ) and/or external photons ( ec process ), where the external photons possibly originate from accretion disk, broad line region ( blr ), or molecular torus. here  , we review the current knowledge about the source of the external seed photons in flat spectrum radio quasars ( fsrqs ) and bl lacertae objects ( bl lacs ), and discuss the possible mechanisms of their origin.
we investigate the memory bounds for winning strategies in two- and polynomial - sized stochastic game arenas ( 2@xmath1-player games ), with and without random states.   we find that the memory limits for any muller condition @xmath2 are set in the form of a number @x Math3, which is an upper bound on the memory needed to win in any 2@Xmath1/2-game using a strategy with memory factorial in the size of the game. however, the lower bound on memory does not hold for randomised strategies, even in non - Stochastic arenas, since they represent possible implementations of the controllers in the synthesis problem.
this paper presents the first study on social associations of distributed peers in peer - to - peer networks.   several peer social networks have been constructed from the real user data collected from the gnutella system, which is a kind of open, decentralized overlay network on top of the internet @xcite, on which distributed users communicate directly to find and share resources. based on the current study on peer betweenness and degree correlations, we will further investigate network hierarchy, peer work load and dynamic properties of p2p social networks by considering their acyclic topological topologies and small world architecture.
we present the complete study of all the lepton polarization asymmetries associated with final state leptons in radiative dileptonic decay ( ) within the framework of minimal supersymmetric standard model ( mssm ).   we first present the qcd corrected effective hamiltonian of the quark level process, including neutral higgs bosons ( nhbs ) effects, and then give the corresponding matrix element and analytic expression of the dilepton invariant mass distribution and forward backward asymmetry. in section   2 we also introduce a new kinematical variable _ photon polarization asymmetry_ which is used to study the effects of polarized photon by introducing a variable   " photon polarization symmetry". with this variable we now have one more kinematics variable ( along with total decay rate, fb asymmetry and three different lepton polarizations ) to test out the exact structure of effective Hamiltonian.
quantum disordered systems are a very active research field in condensed matter physics ( cm ).   disorder plays a central role in modern solid state physics as it can significantly alter electronic normal conductivity, superconductivity and the magnetic properties of dirty alloys. here  , we review our works on strongly correlated fermi - bose mixtures in disordered optical lattices with diagonal on - site energy randomness and discuss a wide variety of cases, including several composite types and quantum phases such as bose glasses, spin glasses and quantum percolation.
the process of information aggregation in social systems gives rise to emergent phenomena like the wisdom of crowds.   a quantitative understanding of the mechanisms by which information is aggregated and used in opinion formation and decision making is needed to understand the emergence of such phenomena. for animals in groups,   recent work in this direction has identified bayesian inference as a mechanism behind their collective behavior. here  , we address the potential of the bayesian approach to explain human decision making under social interaction. using previously published data sets in which the participants first answer in the absence of social information and later with the information about the answers submitted by the previous respondents, we show that simple bayesian models reasonably explain the behavioral data. when the opinions of multiple heterogeneous agents are aggregated, it has been shown that social interaction can lead to misleading estimations of the value of the solution to a question. on the basis of these results, we propose a new model of social decision making based on Bayesian inference.
we present a set of geometric integration algorithms for the symplectically reduced free rigid body, a hamiltonian system on the two - sphere.   the algorithms are based on the lie group framework suitable for the general problem (  ) and use the new mathematical constructs of partial moving frames and partial connections to select generators for use in numerical methods. we present the results of numerical experiments carried out using some of these functions for this system, and show that the relative performance of the algorithms is competitive with classical numerical integrators.
the phase transition from quarks to hadrons, i.e. the onset of confinement and chiral symmetry breaking ( and vice versa ), depends on the chiral imbalance.   we study the change of the phase structure by an equilibrium lattice simulation with a chiral chemical condensate. in this form  , we mimic the topological content ( of a topologically nontrivial gluonic background in heavy ion collisions ) by a standard of chirality imbalance, which is provided by achiral chemicalcondensates. in the continuum limit   the phase diagram is rewritten in the dirac spinor - flavor basis. for the fermionic part of the action we use staggered fermions where the @xmath7 are the standard staggered phase factors : @x Math9 for @x math10.    the results show that the phase transition between quarks and hadrons is observed in terms of a shift to a diagonally located site of a spatial elementary cube over the shortest paths between these sites.
we present a study of the time evolution of a non - equilibrium profile created in a generic two dimensional adsorbate system @xcite with a well understood transition from a commensurate @xmath0 phase to an incommensurate phase.   we find that the profile evolution is governed by the rate of domain wall creation at the boundary and its subsequent diffusion into the interior of the adsorbed layer. for coverage beyond monolayer,   the profiles are characterized by a sharp non - diffusive profile at all times as well as a critical coverage below which the rates of profile evolution slow down exponentially with decreasing coverage. using molecular dynamics simulations, we show that the observed results are qualitatively similar to those observed for the pb / si(111 ) system.. the main results can be understood via microscopic mechanisms that are generic to an adsorbates layer under a compressive strain near a commeningurate - incomensurate transition.
the bicep2 experiment has recently reported the non - vanishing tensor - to - scalar ratio for the higgs boson and the top mass of the right - handed neutrino.   this result has not been confirmed yet, but a number of explanations for the result have been presented. in this work, we analyze the model based on the quantum corrections to the coupling constants ( @xmath10-functions ) for both the standard model ( sm ) and the singlet particles with the help of the latest experimental errors for the cosmological observations within regions for the dark matter ( dm ) mass, for the Right - handed neutron mass, and for the ricci scalar with the coefficients of the two main higgs potentials. as a result  , we will point out that this inflation model can explain the results of cosmsological observations by taking into account the experimental central values for the highest - order coupling constants for the high - energy higgs and top masses and the second - order couplings for the single - particle conjugations between the sm and the real singlet scalar.conclusionsthe results of the numerical analyses show that the proposed model is a good
the magnetic field in the inner 30 parsecs of the galactic center is characterized by a clumpiness resulting from spatial density variations.   we find that in less dense regions, the magnetic field that permeates the dust is poloidal, consistent with that found in the filaments. in these regions,   the matter density is too low for gravity to shear the field into a toroidal configuration. in the dense molecular clouds  , however, the field appears to be generally toroidal, indicating that in such regions the energy density of gravity dominates that of the permeating magnetic field.
percolation theory is the ideal framework for a geometrical description of phase transitions.   the percolation phenomenon takes place when geometric clusters of elementary objects of some system stick to each other giving rise to an infinite network, that spans the whole system. in this article  , we review the history of the study of the critical phenomena of second - order thermal phase transitions, and we show that they are formally identical, as they are characterized by the same basic features : ( 1 ) power law behaviour of the variables near the critical point, with relative exponents ; ( 2 ) scaling relations between the exponents; ( 3 ) universality of thecritical indices.
we have detected the secondary in haro 1 - 14c, a weak - lined pre@xmath4main - sequence star in the ophiuchus star forming region ( hbc 644, herbig & bell 1988 ), in 6 observations distributed over its orbital period.   the radial velocities of the primary and secondary were measured at 1.55 @xmath6 m with the nirspec high - resolution infrared spectrometer using the todcor two - dimensional algorithm and our suite of spectral templates. for each observation, we used the main sequence star hr 8085, rotationally broadened to 12 km s@x math9, which usually provided the best fit to the primary ofharo 1-14c ; the secondary was detected in 6 of these observations.
species are generally considered to be of equal or near - equal biodiversity value within a given taxonomic group.   however, species are discovered and identified because they are different from other species, which suggests that they may differ in value. here   we present a measure of evolutionary value for a species based on its position in a phylogeny, which is a directional, acyclic graph depicting relationships between leaves ( species ). using this measure, we show that species with more unique features are more valuable than species with fewer unique features.    we also show that the shapley value of a species can be extended to include pre - assigned extinction probabilities as well as its phylogenetic diversity. by assigning extinction probabilities to the tips of each edge of a phylogenetic tree,   our measure scales almost perfectly with the original shaply value, but it is less sensitive to the set of sets that individual species are asked to complement.
we propose a family of fluid particle models of two - dimensional lattice as simpler models of membranes : tightly pack molecular particles on a given lattice, and give the particles dynamics by some stochastic process, or by a set of mathematical rules. for more simplicity, we consider single - component, single - layered incompressible systems, and assume no explicit viscosity and an upper bound for the flow velocities on the particles.   after the formulation, we construct two sto chastic models of 2d lattice liquid, as our first steps. one of them is found to be the vicious random walk @xcite in its densest phase and a version of the dynamic latticeliquid model ( dll model ) @xcide in two dimensions.. the other model is constructed as the flow model with a mathematical rule, which has no corresponding known models. here  , we further restrict ourselves to a finite flat honey - comb lattice and simulate the two models with their highest mobility. comparing with similar lattice models such as various lattice random walks or the loop gas model ( sos model )@xcite, we show some statistical properties of the models by the simulation results.
ultraluminous infrared galaxies ( ulirgs ) are rare in the local universe, and are frequently associated with peculiar galaxies, thought to be merging systems.   we have used natural guide star adaptive optics to detect previously unseen circumnuclear star clusters in ngc 6240, a late - stage merger of two massive disk galaxies at the high - redshift edge of the lirg class. using the wfpc2 f450w, f547w, and f814w filters on keck ii, we show that the / ratio is significantly higher in the main body than in the tidal tails of ngc6240, and that this difference is due to the presence of active galactic nuclei ( agn ) in the merger galaxy. by combining these observations with simulations of the scuba telescope s detection of hundreds of sub - mm galaxies, we find that the fractional agn contribution to the bolometric luminosity of the merging galaxy is much lower than previously thought. as a result, we estimate that the total luminous energy density of the merged galaxy has been significantly underestimated.
the solar neutrino experiments are entering a phase of precision measurements.   it is important to give precise description of the lma conversion, both in the sun and in the earth, taking into account various corrections ; * to estimate accuracy of the approximations made ;* to find the precise _ analytic _ expressions for probabilities and observables as functions of the oscillation parameters ( @xmath11,@xmath12 ).    we address these issues in the present paper.. the adiabatic perturbation theory is used to derive the analytical formula for the probability averaged over the distribution of neutrino sources. using this formula,   the regeneration effect in the Earth is calculated., alternative derivations of formulas for the regeneration factor are given.
we study the structure of steady shocks in a multiphase space plasma flow using a momentum - loading approximation.   we find that the hot phase of the flow is more viscous than the cold phase, and that the two phases ahead of the shock are rapidly comoving. for the case in which the cool phase is at rest,   the transition from a hot to a dense phase is faster than expected, but this is not the case for the system of clumped cold phase gas. by taking into account the effects of thermal conduction and mixing, we show that the temperature - dependent coupling between the hot and cold phases is much more effective than might be expected in reality.
we investigate the metastable effects brought about by second neighbor couplings on the scaling regimes of a typical phase separation dynamics in a one - dimensional ( 1d ) system.   we find that the relaxation time of these stochastic processes is very large at low but nonzero - temperature, and that it is driven by the presence of metastable scenarios and activation barriers.    the latter are found to be independent of the spatial dimensionality of the system and can be considered in terms of a quantum spin analogy.
preservation theorems are important results in model theory that relate the form of syntactic expressions to the closure properties of classes they define.   classical preservation theores are almost uniformly false when restricted to the class of all finite relational structures, but also tend to fail when restricted for the class all of finite algebras. here  , we show that within a class of finite bounded lattices, there are many classes that demonstrate the failure of the homomorphism preservation property, and that while the os - tarski preservation theorem does not hold for these classes, it holds for a number of classes of finite algebraic structures at the finite level : for example, the @xmath1-preservation theorem, which asserts that a first - order formula is preserved under taking substructures and direct products if and only if it is equivalent to a universal - horn sentence, fails in the finite setting for relational structures. on the other hand,   the lyndon s positivity theorem ( *?????? ) fails in this setting, while the rossman s finite homomorphisms preservation theorem (*???,@xmath2 ) is recovered in restricted classes of
the conventional model for polar ring formation attributes ring formation to gas capture after the central galaxy has formed.   however, tremaine & yu ( 2000 ) have proposed a different model in which a polar ring galaxy is formed in a dissipative polar merger of two comparable mass disk galaxies with small relative velocity. here   we report observations of stellar and gas velocities in both the s0 and the ring of ngc 4650a using the boller and chivens spectrograph and the marconi ccd at the las campanas baade ( 6.5-m ) telescope. during the merger process,   the ring stars appear to be rotating in a counterrotating direction, whereas in the resonance levitation model they are rotating in an equatorial direction. because the rate of precession of the star orbits matches the pattern speed of the triaxial dark halo, the model predicts that the polar ring will contain two equal mass, counterrotation disk streams. as a result, we have measured the radial motions of the stars in each of the two rings by measuring the local group centric velocity of v@x Math0=2635 km s@xmath1.
we develop statistical inference procedures for extracting both the latent gain signal and the parameters of the stimulus dependency from simulated data.   we test these procedures on simulated data, and demonstrate the success of the model in explaining electrophysiological data obtained from auditory neurons in the anesthetized ferret.
quantum monte carlo ( qmc ) calculations of the vertical electronic transition in the acrolein molecule, ch@xmath1=ch - cho ( symmetry group @xmath2 ), from the spin - singlet ground state ( symmetry a ) to the first spin - Singlet excited state ( a " ), are performed using jastrow - slater wave functions parametrized as  @xcite = ch - cho + 1/ch-cho + 1. the effect of reoptimization of the determinantal part of the complete - active - space ( cas ) wave function on the accuracy of the excitation energy is tested.   the results show that the use of non - reoptimized cas wave functions can be used to obtain reliable excitation energies for the singlet @x Math0 ( co ) vertical transition in qmc without reoptimizing the orbitals for the ground state and the excited state, with a good agreement between the experimental geometry and the quantum chemistry calculations.
this article is a review of the main experimental applications of fluctuation theorems ( fts ) and summarizes the plenary talk given at statphys24. in order to define the main contents   let us consider several simple examples.   the first example is the thermal conduction in a nanotube whose extremities are connected to two heat baths @xcite, i.e. the thermal fluctuations are induced by the coupling of the extremities with the heat baths ; the second example is an electrical model of a conductor of electrical resistance kept at a temperature @xmath1 submitted to a potential difference@xmath11.    the probability of having those negative currents has been studied both theoretically and experimentally within the context of the fluctuations theorem, that we will present in sec..
cervical cancer is the second most common cancer in women worldwide.   the mortality related to cervical cancer can be reduced if this disease is detected at its pre - cancerous state, known as squamous intraepithelial lesion ( sil ). despite widespread use of organized screening ( pap smear ) and diagnostic ( colposcopy ) programs,   approximately 15,900 new cases of cervical cancer and 4,900 cervical cancer related deaths were reported in the united states alone, in 1995. because of the monotony and fatigue associated with reading pap smears ( 50,000 - 300,000 cells per slide ), a cyto - technologist should be limited to evaluating no more than 12,000 smears annually.in this article, we investigate neural network based non - linear methods for algorithm development, and compare them to both the multivariate statistical algorithm ( msa ) and conventional clinical methods. specifically, we investigated the performance of multi - layered perceptron ( mlp ) and radial basis function ( rbf ) networks, and ensembles of these networks, on cervical tissue fluorescence spectra. using the results of our analysis and comparison of the two methods, we propose a novel method for the
the existence of gravitational waves is an unambiguous prediction of the theory of general relativity. yet, despite efforts originating in the early nineteen sixties, gravitational waves have not been detected directly.   there is reasonable hope that gravitational waves will be detected within the next ten years, thanks to a new generation of detectors which use interferometry to monitor the small displacements induced by the passage of a gravitational wave.
a direct - path relative transfer function ( rtf ) estimator is proposed for the localization of a single speech - source in noisy and reverberant environments.   the method is based on a cross - band filter that represents the impulse response in the short - time fourier transform ( stft ) domain by a simplified convolutive transfer function instead of the multiplicative ( mtf ) approximation, as used in @xcite.. the first coefficient of the cross -band filter at different frequencies represents the direct wave propagation path from the source location to the microphone locations, and the second coefficient represents the time difference of arrival ( tdoa ) between the source and the microphone. using the two coefficients as input  , the rtf is estimated from the ratio between the acoustic transfer functions ( atf ) of the two channels. when the stft is used, the interaural phase difference ( ipd ) and the interAural level difference ( ild )   are used to represent the magnitude and argument, respectively, of the corresponding relative transfer functions. in the presence of noise, the ipd and the ild correspond to the direction of the source - to - microphone filtering process, which is represented by
the discovery of a 125 gev scalar boson in the lhc experiment has been a milestone in our understanding of the mechanism of electroweak symmetry - breaking.   it is now possible to directly measure the top yukawa coupling between the higgs boson and all other sm particles we already know, as well as the self - coupling with the hibs self - coupled quantum number. here  , we review the current state of knowledge about the @xmath1 couplings in the extended top sector of the sm, and discuss the implications of these measurements for the search for new physics beyond the sm.
a superbubble is a large, spherical interstellar shell around one or more ob associations.   the shell interior contains hot ( 10@xmath2 k ), shocked wind and ejecta with density of @xmath3 @x Math4 surrounded by the cooler, denser gas of the shell. in this paper, we have combined newly - obtained  ccd images, high - resolution echelle spectroscopy and asca x - ray observations, along with the existing rosat observations to test the hypothesis that the south bar is the result of a blowout from the supernova remnant ( snr ) shell. using the new data, we show that the southern bar is a previously unknown snr shell, and that the expansion velocities of the shells are much faster than expected from the stellar winds and supernova energy inputs.. the size discrepancy between the observed expansion velocity and the model predictions is explained by the fact that the shell is older than the population immediately exterior to the shell, suggesting sequential star formation.
we report results of an extensive investigation of nuclear disassembly in nuclei of @xmath2@xmath3 36 excited to energies as high as 9 mev / u and many observables are related to the critical behavior at an excitation energy of 5.6@x Math10.5 mev.   we have probed the properties of excited quasi - projectile ( qp ) fragments produced in the reactions of 47 mev/u collisions of ~4ar + ~5ni using the tamu nimrod detector and beams from the Tamu k500 super - conducting cyclotron. for the present analysis we have selected reconstructed qp events with total charge number @x math11 @x maths9 12 from violent collisions.    the x - ray energy spectra for different lcp at different laboratory angles and reproduce them using the three source fits, i.e. _ the qp, nn and qt sources. employing this information to determine the energy and angular dependent probabilities we analyze the experimental events once again and, on an event - by - event basis, use a monte carlo sampling method to assign each lcp to one of the sources Qp, or n
we reexamine the problem of localized qubits around a black hole in the fibre bundle theory.   we show that the quantum entanglement is degraded by the gravitational field induced by the black hole and that the decay takes place in complex line bundles over a space constituting by the product of the space of lorentz connections by the tangent bundle of the spacetime manifold. to analyse the quantum teleportation protocol with an epr ( einstein podolsky rosen ) qubit pair when one qubit falls to the blackhole whereas the other one is comoving with it, we compute a formula providing the fidelity of the teleportation.
the altman s z - score ( @xcite ) is the most popular and widely accepted metric for predicting the bankruptcy.   the popularity of @xmath4 may be attributed to its simplicity in computation and ease in its application. however, the present study aims to develop a score based method using a nonlinear form of financial ratios ; designing an index using an equi - probability transformation by fitting a pearson type 3 ( p3 ) distribution to the newly developed z-score say @x math4 ; formulating a rating scheme based on the index ; and comparing the proposed rating scheme with those being employed widely by financial institutions for bankruptcy predictions.
the presence of extraplanar dust in the interstellar thick disks of spiral galaxies has been recognized and studied in many edge - on systems, and it is now established that at least @xmath2 of these galaxies show some form of extraPlanar ( thick disk ) dust and, hence, gas.   however, the physical interpretation of the observed extra Planar dust and its implications for the nature of the galaxy s interstellar thick disk gas is still controversial. in this contribution  , i will summarize some of the evidence that material identified with extraplanor dust may represent a dense, cold medium in the thick disk of galaxies.
the spin - spin coupling of electrons in quantum dots is a very important phenomenon in the physics of semiconductor nanostructures.   the spin - orbit interaction is one of the primary reasons for this coupling, which allows for coupling of the electron spins of two electrons located in different quantum dots even in the absence of tunneling between them. in this paper   we provide a detailed analysis of such an effective spin - Spin - spin interaction for lateral quantum dots in a configuration where the electrostatic effect of each electron on the charge distribution of the other electron is mediated by the " tidal " effect each of the electrons produces on the other via electrostatic forces. because of the spin-orbital interaction, the electric dipole moment ( as well as higher moments ) in each dot couples to its electron spin, and as a result the two spins experience an interaction resembling a magnetic dipole - dipole interaction with effective magnetic moments which can be strongly enhanced by up to a factor of @xmath5 compared to the bohr magneton. through this electrostatic coupling and in combination with the spin orbit interaction  , the spins of both electrons become coupled even if they are confined to well - separated quantum dots with
cal  87 is a low mass x - ray binary ( lmxb ) that exhibits luminous ` supersoft'emission.   it is one of the prototypical members of the new class of supersoft sources ( ssss ), which are characterised by their essential absence of emission above @xmath3kev, and extremely high luminosities ( l@xmath410@x Math5  ergs@x math6 ).    we present here the results of @xMath2  years of optical monitoring of the source, the most extended coverage of this system to date. in addition, we have acquired high speed white light photometry of a single eclipse, enabling us to investigate the detailed structure of the accretor.
the lhc has completed run  1 of the long - range high - energy collider experiment, and the results are in good agreement with the standard model ( sm ).   the discovery by cms and atlas of a ( the? ) higgs boson  @xcite, which has now been detected in three production channels, is the biggest headline of the experiment. here   we discuss what we already know about this newly - discovered particle, and some of the hints it may provide for other new physics, as well as other topics within and beyond the sm.
the kondo mechanism is often used to explain the coherent energy scale of forming heavy renormalized fermionic quasiparticles ( hf ) in the periodic lattice system.   however, this phenomenological picture does nt explain many experimental observations of hf systems, such as the strong temperature dependence of specific heat and bulk susceptibility below the coherent temperature, the coexistence of the magnetism ( often antiferromagnetism ( afm ) or the magnetic long range order(lro ) ) and the heavy qasiparticle in some compounds, and superconductivity in some other compounds. in this paper  , we propose a variational wave function for the ground state of the magnetic hf compounds, in which the local f - orbital wave function exists in the mixed states ( a linear combination of the full local moment state and the fully compensated state ), and we call it " mixed moment state " after the " mixed valence state "@xcite.    we show how this mixed moments state can be realized in the kondo lattice model using the large - n scheme. 	 this part is rather qualitative based on account of the energetics of the competition between different
the objective of this paper is to construct the quark - antiquark potential by making use of the new analytic running coupling.   this potential proves to be rising at large distances ( i.e., providing the confinement region ) and, at the same time, it incorporates the asymptotic freedom at small distances. for practical purposes, a simple approximate formula for the potential   is proposed which interpolates its infrared and ultravioletAsymptotics. in the conclusion   the obtained results are formulated in a compact way, and the further studies in this approach are outlined.
in an interesting saga of papers, dvali, gmez and others have put forward the intriguing suggestion that black holes ( bh ) could be understood as bose - einstein condensates of gravitons.   if this view is correct, this would reveal a deep quantum nature of such fascinating objects and could lead to an alternative understanding of some of the most striking features of bh. in this article   we set up to try to understand them in a different language and, if possible, attempt to be more quantitative. on the process   it is shown that the characteristics of the bose-einstein condenate are uniquely described in terms of the schwarzschild radius of the black hole and the value of a dimensionless parameter, interpreted as a chemical potential. for a non - classical black hole,   the properties of the condensate are not only intimately related to the classical field that sustains it but also to the number of intervening gravitrons.
abstractmany communication protocols implicitly require that the communicating parties share a reference frame.   we explore how well alice can communicate quantum information to bob after supplying him with a bounded - size token of her reference frame in the form of a compact lie group, where the system is prepared in the state @xmath2 and the reference frame token in the states @x Mathcal{g } ( |e\rangle \langle e| \otimes \rho \,,\ ] ) relative to alice s local reference frame.we find that alice transmits her quantum systems into the joint state of @x math3 and@xmath1 using spin-1/2 particles, which are not correlated with alice’s reference frame, and that she can encode the quantum information into the rotationally - invariant degrees of freedom of many qubits without encoding the classical bits or logical qubits into the physical qubits. by virtue of this, alice does not need to know the entire message string at the outset to achieve her optimal communication rate, nor does bob need to store all of the systems coherently until he has received the entire sequence of physical qubit states, whereas such
the dynamics of surface polarization clusters of barium titanate ( batio@xmath0 ) across the curie temperature ( @xmath1 ) has been studied by the picosecond soft x - ray laser speckle measurement in combination with the technique of pump probe spectroscopy.   it has been found that the ferroelectric clusters of nano scale are created in the paraelectric batio=xmath2 and tend to be smeared out gradually on the way back to the equilibrium parae electric state. as a result, the cluster relaxation time is reduced down to a few nanometers, and the cluster decay rate decreases upon approaching @x Math1, indicating a critical slowing down of the cluster Relaxation time. from a theoretical point of view, the observed novel behaviors of ferro electric cluster observed by namikawa   are examined from a path integral quantum monte carlo method, which is computationally feasible to handle the quantum many body problems, for it allows the system to be treated without making any approximation.
the relativistic equations for the collapse of a charged fluid ball were obtained by bekenstein @xcite. in this paper   we study the stellar structure and temporal evolution of compact charged fluid spheres, independently on the mechanism by which the matter acquires an electric charge.   two codes were built and are used in the present study : one to obtain neutron stars models in hydrostatic equilibrium, presented in the sec.  code, and the other to obtain the model of a zero temperature neutron gas in the seceos code. from the present work it is possible to understand if the coulomb repulsion will prevent or not the total collapse of ( charged ) charged fluid balls, and which are the stability limits for a charged relativists star.
@xcite is a two - dimensional ( 2d ) single layer of carbon atoms that has attracted tremendous attention because of its unique massless dirac fermion - like electronic properties and potential applications in electronic devices.   remarkably, theoretical calculations predicted that quantum confinement and edge effects make narrow gn ( width w @xmath1 10 nm ) into semiconductors, which differs from single - walled carbon nanotubes that contain some metallic species. to realize the practical potential of narrow gn, methods for their mass production are sorely needed. in the present work, we propose that wide gn can be made semiconducting by partial hydrogenation, because the hydrogenation starts from the edges of gn and proceeds gradually toward the middle of the gn. in this way  , the difficulty of directly synthesizing narrow and smooth gn could be avoided.
factorization of the hard - scattering coefficient in hadron - hadron collisions is one of the most important properties of quantum field theory.   the standard expectation is that the cross section is a convolution of a hard scattering coefficient, parton densities, fragmentation functions and a possible soft function.. however, as can be seen from @xcite, process - dependent wilson lines appear to be needed in the inclusive production of two high - transverse - momentum particles in hadroproduction of hadrons. in this paper   we show that this situation definitively leads to a breakdown of factorization.    the problem is solved by examining a particular process in a model field theory where problems in the contour deformation directly affect the value of the cross sections at the lowest possible order of perturbation theory. since proofs of factorisation apply to quantum field theories in general ( if they are renormalizable ), the construction of a counterexample, to demonstrate and to understand a failure of the normal methods of proof, is conveniently done in a simple model theory.
ngc 6240 is one of the best studied composite galaxies, hosting a luminous starburst and two active galactic nuclei ( agns ) obscured by gas and dust. with a bolometric luminosity of @xmath0 @xcite, emitted predominantly in the infrared,   this galaxy is a borderline case of the ultra - luminous infrared galaxies ( ulirgs ).   we observed the two distinct nuclei at high angular resolution with adaptive optics. both, the northern and southern nucleus ( hereafter the n nucleus and the s nucleus respectively ) are surrounded by bright gas components. to our knowledge, this is the first time that near - ir images and spectra have been obtained at such high spatial resolution from the n and s nuclei of ngc 6 240.    the results show that the dominant source of energy emitted in the near - infrared from the nuclear region of ng c 6240 comes from thermal heating by the central source and supernovae, dissociative shocks, and ultraviolet fluorescence.
the isoperimetric problem is a classical subject in differential geometry.   it consists in finding on a riemannian manifold the regions that minimize the perimeter among sets enclosing the same volume and their boundaries are is operable hypersurfaces. despite the long history of the problem  , it remains largely open with few 3-manifolds where the problem is completely understood. here   we give a complete solution for the isoperimeteretric problem in the lens spaces with large fundamental group in the real projective space, which is a special case of an important family of riemanian manifolds, namely the lens spacings. using the standard product metric, we show that the solutions are either geodesic spheres or tori of revolution about geodesics for all non - diffeomorphic 3- manifolds in the set of hausdorff dimension three.. the results are compared with those of previous work in the field of geometric measure theory.
in the third egret catalog @xcite unidentified @xmath0-ray sources accounted for more than a half of the discrete sources detected by egret. despite a great effort,   most of them can not be associated with the known sources detected at low energies up to now.   there are recent theoretical works trying to explain the unidentified sources as annihilating dark matter clumps within the milky way ( mw )@xcite. in the present work we assume that neutralino forms dark matter and work in the frame of supersymmetric extension of the standard model. assuming that none of the unidentified egret sources is from dark matter annihilation we will study how the properties of neutralino are constrained resorting to the numerical simulation result of dark matterclumps distribution. using the results of the simulations we will show that the non - detection of subhalos finally shows a constraint on the supersymmetry parameter space.
the butcher  oemler ( bo ) effect is a well - known phenomenon that describes the evolution of galaxies within clusters of galaxies with redshift.   it is defined as the excess fraction of galaxies that are bluer than the rest frame of the cluster s colour  magnitude relationship ( @xmath2 ), which is found to be bluer at low redshifts than at larger redsh shifts.    this article presents a historical review of progress into the understanding of the origins of the bo effect and discusses attempts to tie together several strands of observational evidence ( photometric, spectroscopic, and morphological ) in order to better understand the origin of the effect. while the original work has been followed up by many other authors who show that the cores of @x math9 clusters do contain blue galaxies, there is also evidence for an evolution in the blue fraction with red shift, increasing from @x Math5 at low Redshifts ( @ xmath6 ) to @x maths7 at larger Redshifting ( @Xmath8 ). here  , we discuss the possible mechanisms for this evolution, focusing on how selection effects can alter the calculated values of@xMath2.
the formation of a bubble is intimately dependent on the evolution and mass loss history of the central massive star.   we present recent observations of a supernova remnant ( snr ) shell in n11b in the lmc, where the stellar winds and the supernova ejecta sweep up and compress the ambient medium into shells, called bubbles or superbubbles, which can grow up to a few @xmath0 pc before the star explodes. as a result,   the bubble interior is very hot, and the hot / cold gas interfaces in the bubble are highly sensitive to the thermal pressure of the shock - shocked stellar wind. using x - ray spectroscopy, we show that the heated interior of the bubble is dominated by a dense swept - up shell with a temperature of about 20 kj / cm2, while the cold interior is characterized by a relatively small temperature of < 10 kj/cm2 at the interface between the hot and cold gas layers. here  , we compare the properties of the two types of bubbles, interstellar and wolf - rayet bubbles, and discuss the possible mechanisms underlying their formation.
the leading order bfkl kernel, derived from feynman diagrams in momentum space, is a meromorphic function.   it couples to the impact factors of colourless particles which, because of gauge invariance, vanish as one of the two reggeized gluons carries a zero transverse momentum. on the other hand, under the mbius transformations in the space of transverse coordinates, the bf Klarke equation has the bootstrap solution, which represents a fundamental consistency property derived from the s - channel unitarity. in this paper   we define a similarity transform, @xmath5, which takes us from the Mbius space of functions ( m space ) to the new deformed space (@xmath7 space ) of functions in which the bootstrapped solution is fulfilled. using the same transformation  , we also define a ` deformed'spectroscopic representation of the b fkl kernel in terms of conformal eigenfunctions, and compute the transformed generators of the monte carlo group @x Math0.
we study certain models with infinitely many absorbing states. at a certain value of a control parameter @xmath0, these models undergo a transition between active and absorbing phases.   but the interesting point is a novel type of this transition : it seems to combine some features of both discontinuous and continuous transitions. namely, at @x Math0 an order parameter jumps discontinuously to zero but in addition that the order parameter has a power - law singularity upon approaching the transition point from the active phase. moreover, some elementary arguments, supported by monte carlo simulations, prompted us to predict the exact location of the transition points in both models, namely, @x math1.
we have studied the influence of particle arrival time distribution at different distances on estimated density for yakutsk and agasa.   simulation showed that distortion of estimated density at the yakutksk array can not result in such miscalculation. to explain this contradiction with agasa a.   watson assumed that at the Yakutsk array such showers are skipped due to inadequate short integration time for large distances from the axis. here   we provide simulation of detector s response for distances @xmath9 and 2000  m, based on the particle distribution approximation obtained at agasa   @xcite. simulations show that there is no significant underestimation of particle density for distances up to 2000 m for density estimating system at the Yuktosk array.    it is connected with the fact that input of rc   convector is constantly open and in the case of wide signal this may lead to density overestimation due to features of converter.
we study possible realizations of quantum feedback and probabilistic error correction in an optical cavity qed system, an open quantum system that is an important candidate for realistic implementations of quantum information processing.   we consider a two - mode driven optical cavity qued system in the regime of intermediate coupling, where the dipole coupling constant is comparable to the cavity and spontaneous emission decay rates. using a truncated atomic basis, we show that the conditional dynamics of the system can be used to capture and release a quantum state, thus realizing the elements of a quantum eraser @xcite.
we investigate the effects of stellar blending on the cepheid distance scale by studying two local group spiral galaxies, m31 and m33.   we identify some of the extragalactic cepheids discovered by the direct project on archival wfpc2 images and compare them to our ground - based data to estimate the impact of blending on our photometry, taking advantage of their superior resolution. in both galaxies,   the observed cep heids are associated with one or more intrinsically luminous stars, which can not be detected within the observed point - spread function ( psf ) by photometric analysis. using a new statistical model, we show that the number of blends is reduced by ~4% in m31 but not in m33 due to the presence of a companion star at a distance less than @xmath7 from the cephalogram. for m31, the effect of blending is most pronounced in the period - luminosity relation, where the contribution of the companion star is higher than that of the ceti - th blend. for M33, the influence of crowding is much smaller, with the contributions of the companions being lower than those of the other companions.
the rotation velocities of the mass donating ( cool ) components of the d symbiotic stars ( sss ) are measured using a cross correlation function ( ccf ) approach.   the results show that the mass donors in sss are faster rotators than the isolated giants or those in wide binary systems, and that they are also more likely to have co - rotation with the white dwarf.
metamaterials are artificial composite materials which possess unusual electromagnetic properties not normally found in natural materials.   it is generally accepted that the electromagnetic properties of both regular and random arrays of scatterers are quite similar if the distances between inclusions are electrically small. in a recent paper   @xcite by helgert et al., we studied the effect of positional randomness on the electromagnetic behavior of grids of resonant particles which can exhibit both electric and magnetic resonant responses. to this end, we introduce a simple model, which allows us to analyze the reflective, transmitting, and absorptive properties of multi - resonant grids, both in the regular and amorphous states.    the theory is confirmed by numerical simulations using an example of the same metasurface as that studied in ref..@xmath0, and the results reveal the mechanisms of resonance broadening and damping in Amorphous structures and explain the strong differences in resonance broadener in different resonant modes.
the azimuthal correlations of electron - muon pairs produced from open heavy flavor decays, primarily @xmath17, in and collisions using the phenix detector at the relativistic heavy ion collider ( rhic ) have been measured.   the results are in quantitative agreement with energy loss models   @xcite and saturation models @xcite.
the grassmannian model of the zakharov system @xcite with fermions is considered.   the classical hamiltonian is obtained by averaging the quantum one using the product of the following coherent states ( or directly by substitution ) : grassmann - valued odd ( anticommuting ) complex functions, grassman - valued even ( commuting ) functions, and grass mann - valued commutative functions. in this paper   we consider the simplest model namely a nonlinear chain and describe the phonons and electrons as functions having values in the even and the odd sector of an infinitely generated grassmann algebra ( this can be done either directly or using coherent states ). for the classical case we assume further that all fields and their derivatives commute or anticommute, and that the soliton interaction is nonelastic having a dressing in the fermionic part.the results are discussed in terms of the supersymmetric bilinear formalism.
we study the rate of heterogeneous nucleation of a crystal near a vapour - liquid transition, a phase transition between two phases which are both meta- or unstable with respect to crystallisation.   we find that the free energy barrier to heterogenous nucleation is very large at this transition, for example @xmath0c, but not at any other phase transition. in the case of a wetting transition,   the barrier is much smaller than it is at the other transition and the nucleation barrier is only slightly larger at the second transition.the results are compared with those of earlier work on homogeneous nucleated crystals near a bulk critical point.
the fundamental plane is a famous correlation between three variables, the effective radius, the central velocity dispersion and the surface brightness within its effective radius @xcite.   for more than 20 years of investigations, it has resisted a satisfactory physical understanding. in this paper  , we show that correlations between the three variables of the fundamental plane can easily be the artifact of the effect of another parameter influencing all.we propose that the confounding parameter(s ) is ( are ) related to evolution.we also discuss why and how the evolution of galaxies is probably the confounding factor.
we present a new analysis of the spectrum of superpartners and the cross - section of their production in the minimal supersymmetric standard model with supergravity inspired supersymmetry breaking terms.   the results are based on the measurement of the cosmic microwave background and the cosmic ray flux and spectrum of the gamma rays and antiparticles coming to the earth from the astroparticle physics experiments. taking into account all these constraints   one can choose parameters in a very narrow region of the parameter space, which is well within the reach of modern hadron colliders. choosing parameters in this region   results in the calculation of the spectra of light charginos and light sleptons and the corresponding cross - sections for the strong and weak processes as well as the light chargino production. using the xray data from the tevatron and the soon coming lhc Hadron collider   we show that the strength of the coupling between the weak process and the strong process is stronger than that of the squark and gluino processes, and that the conjugation of the charginos with the sleptons is more strongly coupled than with the lep2 + leptons.
the self - consistent green s function ( scgf ) theory of nuclear matter has been proposed for the evaluation of the binding energy and saturation properties of normal nuclei, starting from a realistic nucleon - nucleon ( @xmath0 ) interaction without any adjustment of a free parameter @xcite.   the results of the calculations are compared with those of the brueckner - bethe - goldstone ( bhf ) approximation, which is widely used in nuclear physics. to investigate whether an improven and more consistent treatment of the many - body system, still based on nonrelativistic dynamics and two - body forces, can provide new information on the saturation problem ofnuclear matter, it is shown that the solution of this problem is dependent on the choice of the single particle potential,@xmath3, and also on the influence of the short - range and tensor components of the @x Math0 scattering correlation.
we propose a setup for the detection of the mean value of the atomic field operator by means of the scattered light emitted by a quantum gas.   this setup is based on an interferometer for bose - einstein condensates ( bec ), and is based in part on a scheme in which the second system is not necessarily a bec. in this scheme,   the photon flux of the photons scattered by the scattering atoms of the quantum gas is used to determine the condensate fraction of the second systems.    we show that this setup can be extended to detect the first - order correlation function of an atomic gas, when the two illuminated regions belong to the same quantum gas, and that it allows one to measure the correlation functions of matter in the flux of its scattered light.
the quasi - satellite phenomenon @xcite is studied in terms of a simple approximate analytical theory.   the gravity field that we used in the tests was the spherical function expansion, following@xcite, plus luni - solar terms, but we also studied the simple @xmath3 field model. using different model potentials   we show that the constant force model is the simplest one to use and it seems to work.
the nature of the helix - coil transition in polypeptides is a long - standing topic of research and has been studied with various methods including renormalization group techniques @xcite.   we study the nonequilibrium evolution process of the chain size scaling factor @xmath0 chains in short - time monte carlo ( mc ) simulations using a complimentary approach to protein science that leaves the  physical " dynamics unchanged. for the first time  , we show that at criticality universality and scaling are already present early in the evolution of systems. by combining the scaling of the second cumulant of the system with the scale of the first one, we obtain estimates of the critical exponent@xmath20 for the formation of the limes of the 24-residue human parathyroid fragment pth(1 - 34 ). from these estimates, we find that the global persistence probability p(t ) is expected to decay algebraically at critical temperature where the critical temperature is defined as the temperature at which the order parameter @x Math3 changes its sign for the 1st time.
galactic black hole binaries have been discovered in both x - ray ( 1 - 10 kev ) and hard x -ray ( 20 - 300 kev)bands since the launch of the compton gamma ray observatory in april 1991.   a variety of high energy spectra and light curves have been observed from many of them, including some of them with highly relativistic jets. in this review article   we try to avoid any significant overlapping with other review articles, by summarizing these new and important multiwavelength observations, and exploring the physical connections between observations made at different wavelengths to obtain more complete pictures of these systems.
the accuracy and reliability of the numerical values of the heisenberg exchange parameters @xmath0 depend on the functional used for the exchange and correlation ( xc ) energy, being this the only approximated part of the density functional theory ( dft ) total energy.   calculations based on well - known local functionals, namely the local density approximation ( lda ) and the generalised gradient approximation ( gga ), are successful with itinerant magnetism in transition metals @xcite, but largely over- or under - estimate the exchange parameters in many other situations. here   we present a new method for estimating the exchange parameter @x Math0 using a combination of self - interaction corrected ( sic ) and non - local exchange functionals. by combining the hartree - fock ( hf ) and hybrid - functionals  , we show that the proposed method is able to provide a systematic improvement in the agreement between the predicted and experimental values of @x math0 for a number of interesting physical systems including, transition metal monoxides, silver halides, noble metal oxides, ferroelectric materials, high - k materials, diluted magnetic semiconductors and also quantum transport.
the effects of temperature and pressure on the structure of europium titanate ( eutio@xmath0 ) have been investigated by synchrotron x - ray diffraction at different temperatures and pressures.   the results show that the antiferrodistortive transition to a tetragonal structure takes place in both systems on cooling, and is attributed to an octahedral rotational instability which is first detected by an anomaly in the specific heat close to room temperature ( 282 k ) @xcite. for high pressure experiments,   several pressure ramps were carried out up to a maximum pressure of 50.3 ( 1 ) gpa using neel as a pressure transmitting medium. from the results of these experiments, we have established the p - t phase diagram of eutiosm titanate with the purpose of exploring the possibility of any further transitions in an extended pressure - temperature range as compared to previous studies.
we consider a system of spin-@xmath1 fermions with mass @xmath2 confined in a one - dimensional ( 1d ) harmonic trap with oscillator frequency.   the particles interact via a short - range interaction modelled by a delta function of coupling strength, and we find that for a system consisting of only six particles ( five identical fermion and a single impurity of the same mass as the other particles ) one can see the emergence of a many - body system taking place. using these results  , we show that it is possible to construct a fermi polaron from a few - body perspective.
we study the stability of all possible compressive boundary - layer solutions of the isentropic compressible navier - stokes equations on the quarter - plane.   our method of analysis is by a combination of asymptotic ode techniques and numerical evans function computations, following a basic approach introduced recently in @xcite for the study of the closely related shock wave case. here  , there are interesting complications associated with the richer class of boundary - layers as compared to possible shock solutions, the delicate stability properties of the inflow case, and, in the outflow case, the nonstandard eigenvalue problem arising from reduction to lagrangian coordinates. using these complications as a starting point, we show that compression boundary layers that are uniformly noncharacteristic in a sense ( specifically, bounded away from @xmath26 ) are _ unconditionally stable _, independent of amplitude, on the range @x Math27 $ ] considered in our numerical computations.. we show by energy estimates that _ outflow boundary layers are also stable also in the characteristic limit, analogous to the small - amplitude limit for the shock case.
the ground state of an electron gas at zero temperature is well described by landau s theory of fermi liquids @xcite.   however, recent experiments on metallic as well as semiconductor wires suggest that the phase coherence time saturates at very low temperature @xmath4 and that this saturation is due to the presence of magnetic impurities in the samples. here   we discuss the influence of these impurities on the effects of the kondo effect and the spin glass transition temperature on the electron decoherence at zero temperatures.
the globule - coil structural transition of a self - attracting polymer is a fundamental issue in polymer physics.   the nature of this transition has been studied extensively in the past several decades by experimental, theoretical, and simulation approaches. for a flexible self - attractive polymer,   mean - field theories predicted a second - order continuous globular - coil phase - transition as the ambient temperature is elevated ; however, there are still some controversies in the literature concerning monte carlo simulations in 3d. here  , we investigate the thermodynamic behavior of a semiflexible polymer at very low temperature by means of two - dimensional ( 2d ) and three - dimensional(3d ) molecular dynamics simulations. to test the hypothesis that the shape of the polymer can be changed by changing environmental temperature and/or external force, we have used a combination of single - molecule manipulation experiments and high - resolution molecular dynamics models of the global structure of the polymers. using the same solvent molecules, we show that the polymer undergoes a first - order globules - coil transition with a critical temperature at the so - called theta - point, where the polymer achieves a delicate balance among monomer - monomer attractions, excluded - volume
the simplest grand unified theory was proposed in 1974 by h.  georgi and s.  glashow   @xcite.   this theory is based on the @xmath0 gauge symmetry and makes several striking predictions. in this letter   we discuss the different realistic scenarios for @x Math0 unification proposed in refs.,  @xcite and @x math2. after a detailed discussion we propose a new grand unified model where the charged fermion masses are generated at the renormalizable level, while the neutrino masses are generate at the quantum level through the zee mechanism  . this model predicts the possibility to observe exotic signals at current and future colliders.
the golf - ng instrument is a 15 points resonant scattering spectrophotometer observing in the blue and red wings of the d1 sodium line at the observatorio del teide ( tenerife ).   the objective is to reduce at maximum all the instrumental noise sources in order to increase the sensitivity to solar oscillations. in this preliminary analysis, we present here the first preliminary results from a 2008 summer campaign of simultaneous observations by the ground - based Golf - ng and the space - based golf / soho instruments.
the experimental determination of the @xmath0-factors of hydrogen - like ions with a non - zero nuclear spin has made much progress in the past years.   the goal of the present investigation is to perform an _ ab initio _ calculation of the bound - electron @x Math0-factor of a hydrogen -like ion with aNon-zero nuclear spin, namely, the self - energy, the vacuum - polarization, and the nuclear magnetization distribution corrections. for the first time  , we calculate the dominant corrections to the relativistic theory of the nuclear magnetic shielding constant ( which describes the effective reduction of the coupling of the binding nuclear moment to an external magnetic field caused by the shell electron(s ), @x math5 ) of the atomic @x maths0 factor in a system under investigation. as a result, we show that the nuclear - spin dependent part of the atomistic @xMath0- Factor can be parameterized in terms of the nmagnetic shielding constant, which is the effect of the spin dependence of the quantum electrodynamical parameters on the magnetic dipole moments of the electrons in the atom. from the results of this work,   it can be
we report the results of a survey of the southern sky for gravitational lenses using the vla ( vla a - array ).   the object presented in this paper, j16320033 , is the fourth confirmed gravitational lens to date, and is a quasar that lies along nearly the same line of sight as a galaxy with multiple compact components in 8.5  ghz vla images. from the radio observations, we find a third faint component at the @xmath6 level, which is not detected in any of the other images except the second ( deeper ) merlin image ; it is located close to the lens galaxy and nearly along the line between the two compact components. by contrast, the optical observations show that the three components are unresolved in all the images except one, in which the third component is partially resolved.    the nature of the third faint radio component is discussed in this section, along with possible implications for the mass distribution of the lens Galaxy if it is an additional quasar image. finally, the evidence that j1632033  is a gravitationally lensed quasar is summarized, and prospects for future observations that would use the system as a probe of cosmology or galactic
the production of high-@xmath0 heavy quarks from jet conversions in heavy ion collisions is studied at the relativistic heavy ion collider ( rhic ).   the yield of these quarks is suppressed by the quenching of the leading jet parton by induced gluon radiation, which is expected to be the largest contributor to the energy loss of the high- @x Math0 parton. however, the mechanism for this suppression is found to be non - perturbative and can be explained by leading order processes in perturbation theory multiplied by a @xmath6-factor.
the origin of kinetic friction in granular materials is not well understood, even in an assembly of simple frictionless inelastic particles.   we have studied the origin of this friction by numerical simulation of a small number of inelastically intervening particles between the upper and lower walls of a granular material with a low degree of freedom of motion. using the mser model of friction, we numerically calculate the resistance force exerted on the upper wall by the intervening particles, and discuss the origin for the kinetic friction. to simplify the system as much as possible, we neglect tangential forces such as the mindlin force and rotational motion.we find that the friction is due to a stick - slip motion caused by the friction between the intervening particle and the surface, which is related to the formation of a force - chain network above the critical density.
the large area telescope ( lat ) is a high - energy gamma - ray detector onboard the gamma - rays large area space telescope ( glast ) satellite to be launched to low - earth orbit in 2007.   we have developed a cosmic - ray background flux model based on existing measurements and theoretical predictions, and validated the model by comparing with the data of a balloon flight engineering model ( bfem ) that was used to validate the basic design of lat in a space - like environment.the model covers the entire solid angle, a wide energy range between 10  mev to 100  gev and abundant components ( proton, alpha,@xmath10, @xmath11 and gamma ray).the model functions as " a working model of cosmic - Ray background fluxes " for high energy astrophysical missions.
quantum process tomography ( qpt ) is the main tool for experimental characterization of quantum gates, being developed for potential use in a quantum computer.   qpt has been realized in numerous experiments, practically in all types of qubit systems, including, e.g., nmr, linear optics, ion traps, and superconducting qubits. unfortunately, qpt requires resources, which scale exponentially with the number of qubits ; therefore, the full qpt with 4 and more qubits seems to be impractical. besides the standard matrix @xmath0, there are other ways to represent qpt results, such as the so - called pauli transfer matrix@xmath5. in this paper   we discuss one more way of representing the experimental qpt result @xcite, which is essentially the standard @x Math0-matrix representation in the paulis basis, with the only difference being that we factor out the desired unitary operation @x math6, so that the error matrix @Xmath7 describes only the imperfections of the experimental quantum gate.    we show that the errors described by the error matrices can be represented by the same error matrix as the error channel
ngc  3077 is a low - luminosity peculiar galaxy located in the @xmath95 mpc.   it is characterized by its dusty appearance, many compact blue knots, and its very high@xmath6 for typical s0 or i0 galaxies. at the periphery of ngc   3077, there is also a prominent stellar complex, which was nicknamed the " garland " by bbdt74. as part of a long  term project to obtain distances to all the galaxies in the local volume using the tip of the red giant branch ( trgb ) method, we have made v and i observations of two regions in the halo of ng c3077 using wide field planetary camera 2 ( wfpc2 ) on board the hubble space telescope ( hst ). here  , we report the detection of resolved upper main sequence stars in the'garland'using the trgb method, followed by a discussion of the upper main sequences of stars observed in our frames. based on the results of these observations, we propose that the star population in the garland is composed of a number of rgb stars, which are likely to be blue supergiants.
there is no currently accepted scenario for the formation of the parent bodies of primitive meteorites which accounts for the most obvious of their properties.   these properties include ( a ) dominance by aerodynamically well - sorted mineral particles of sub - mm size ; ( b ) class - to - class variation in well - defined physical, chemical, and isotopic properties ; ( c ) a spread of 1 myr or so between the formation times of the oldest and youngest objects found in the same meteorite ; ( d ) a spreading of 1 - 3 myr in radiometric ages of different meteorite types ; and ( e ) a dearth of melted asteroids, with model results for even some melted asteroids which imply myr delays in formation relative to ancient minerals. in this paper  , we outline a possible path by which entire batches of mm - size, Aerodynamically sorted particles might proceed directly in turbulence ( even if sporadically ) to planetesimals having the properties outlined above.we find that sufficiently large and dense clumps of mm-size particles can form by turbulent concentration such that, even if classical gravitational instability ca nt operate, their self - gravity may still allow them to survive disruptive forces and slowly
dissect - cf is a new discrete event based energy consumption simulator for clouds and federations ( dissect - cf ).   it is a versatile simulation framework that allows researchers to model the internal behaviour of infrastructure as a service ( iaas ) systems in a more complete way than existing simulators such as @xcite, groudsim and simgrid. compared to the previously mentioned simulators, dissect-cf offers two major benefits : a unified resource sharing model, and a more comprehensive iaaas stack simulation. by allowing the user to derive energy consumption from multiple resource usage counters,   dissect- cf could foster research on cloud schedulers that could either have better insight into internal ianas behaviour or collaborate with internal scheduling algorithms in order to achieve previously unprecedented flexibility, adaptability and elasticity in future cloud systems.database url :   http://www.ncbi.nlm.nih.gov/pubmed/software/explorer/dissect-cf
an effective theory for heavy mesons, implementing the heavy quark symmetries, has been very successful at the phenomenological level.   predictions are easily obtained once the unknown effective couplings are fixed from experimental data. in order to go beyond the symmetry approach, one should be able to derive the free couplings at the meson lagrangian level from a more fundamental theory, for example directly from quantum chromodynamics ( qcd ). here   we extend the approach of @xcite and @xcites to the description of the heavy meson interactions for the doublets with spin / parity, i.e. s- and p - wave heavy - light mesons. using a model based on an effective constituent quark - meson Lagrangian containing both light and heavy degrees of freedom, we obtain predictions for semileptonic @xmath6 decays into negative parity and positive parity charmed resonances ; in particular we compute the relevant universal form factors that describe such decays in the limit and discuss the bjorken sum rule. in the strong and radiative decays we find that the number of free parameters for the model is reduced by a factor of 2.5.
a copious amount of heavy quarks produced in two - photon collisions will be generated at high energy @xmath0 colliders such as lep2 and a future next linear collider ( nlc ).   the largest fraction of these will come from so - called no - tag events, in which neither of the leptons generating the photons is seen. however, due to the high energy and luminosity of these machines, a sizeable number of them will be produced in events where either the outgoing lepton or the tagged lepton is tagged ( " single - tag event " ). in such events, the photon coming from the tagging lepton   is far off - shell and spacelike, hence this reaction amounts to deeply inelastic electroproduction of heavy Quarks on a photon target.    the interesting feature of single - tags is that this separation occurs quite naturally in the deeply inelsastic bjorken scaling variable@xmath4, and is unambiguous to next - to - leading order ( nlo ) in qcd in @xcite. in this letter   we employ the results of a perturbative qcd calculation of the cross section for charm production
a large spherical liquid body in absence of gravitational forces is a paradigmatic system to study a variety of physical phenomena, but the control of its position and stability in a residual acceleration environment is a delicate task.   we have designed and implemented a drop generation system that allows the manipulation of perfectly isolated centimeter - sized levitating drops in microgravity using an injector tube able to attach and stabilize them. during each microgravity phase ( 20 s duration ),   one captured centimetric drop was created by smoothly exppelling distilled water through a custom - designed aluminium injecting tube, which was filled with hydrophilic porous foam for two purposes : first, to guarantee a homogeneous laminar flow and thereby control the actual drop volume during its formation ; and second, to favor the attachment of the drop by water capillary cohesive forces through the tube foam interface. here  , we describe the intrumentation designed for the creation of the droplet and the generation of the bubble, as well as the physical parameters influencing the performance of the experiment. at the same time, we present a brief overview of the experimental setup used to create and observe cavitation bubbles inside the drop.
the seizure generalization hypothesis, which underlies the mechanism of modified - electroconvulsive therapy ( m - ect ), holds that propagation of induced seizure throughout the entire brain is essential for effective ect intervention@xcite.   however, there are many clinical cases where, due to high thresholds, seizure is not induced by the maximum dose of electrical charge. in these cases,   the following procedures are considered options for inducing seizure ; ( i ) using the older method of sine - wave ect ( ii ) promoting hyperventilation in patients @xcite ( iii ) using anesthetic agents such as ketamine with ect ( iv ) using pulse - wave electrophysiological techniques such as a somatic thymatron ect device. recently randomized control trials focusing on pulse width have been conducted@xicite and reported that the ultrabrief pulse method, in which pulse width is less than 0.3millisecond ( ms ), induces more therapeutic effects and fewer side effects and requires less electrical charge to induce seizure compared to conventional brief pulse ( 1.5ms).we experienced a case of schizophrenia in which m-ect with 1.0 and 1.4ms width pulse ( referred to as `
recently, an exploration of the vacuum solutions of pure @xmath0 gravity uncovered new black hole solutions, resulting, in part, from the lack of a generalized birkhoff theorem @xcite.   the authors interpreted these solutions as a part of the strong coupling limit of general relativity ( gr ). in this paper, we show that the vacuum space of @x Math0 gravity permits new traversable wormhole and non - singular black hole solution. using the same metric signature as the most general quadratic gravitational action,  s = d^4x f(r)+s_m, we find that the wormhole can be traversed through the throat of a black hole by means of a single linear trajectory. for some conditions,   observers and light rays can also traverse the throat with respect to the tunneling end of the wormholes.    we emphasize that these structures are supported only by the vacuum and do not require any unusual states of matter.
reionization represents the last major epoch of cosmic evolution left to explore.   study of the intergalactic medium during that time is a primary science driver for essentially all future large - area telescopes, at all wavelengths. in this paper   we discuss how the radio interferometric imaging techniques are going to affect the foreground source modeling and subsequent removal from the data - set in order to search for the signal from the epoch of reionization ( eor ) using the largest expected cosmic stromgren sphere ( css ) as the only signature that can be detected in the image domain by the upcoming low - frequency radio - telescopes.we consider two frequency independent errors : i ) position error in the global sky model ( gsm ) that is used to remove the bright sources above the @xmath11 level and ii ) residual calibration error which is usually considered as a function of the side - lobes of the synthesized beam.we show that the propagation of these errors is dependent on the frequency of the synthesis of the ionosphere and the size of the primary beam. when the main beam is synthesized at a frequency of 1.5  khz, the gsm is not accurate enough to detect the eor
the measurement of anomalous hall effect@xcite ( ahe ) in ferromagnetic metals and semiconductors is a powerful tool to characterize the magnetization of thin films and mesoscopic objects.   the theoretical aspects and possible physical mechanisms of ahe are still not quite well understood, and the great efforts are directed now toward the physical explanation of a he in magnetic semiconductor, pyroclore crystals, and magnetic compounds with inhomogeneous magnetization. in this paper   we present the result of calculations taking into account the effect of impurity scattering on the off - diagonal conductivity of @xcite in a model of two - dimensional electron gas with spin - orbit ( so ) interaction in the form of rashba term. using the kubo formula for conductivity @xmath2, we show that there is another intrinsic contribution to ahe related to the electron states near the fermi surface, which is not geometric, and it can be of the same order of magnitude as the berry - phase - induced one. at the same time, the non - geometric contribution does not vanish if we finally take the limit of @x Math3.
the deconfinement and chiral transition in qcd at non - zero temperature are discussed using highly improved staggered quark ( hisq ) action and tree - level improved gauge action.   the effects of these actions are compared with the continuum extrapolated data obtained with so - called stout staggered quarks and finer lattices, which show that the two transitions are no longer interconnected.
adaptive features of a bio - signaling system are essential for its robustness and efficiency.   the present study is based on the adaptive and strategic characterization of few adaptive biochemical network motifs, some of which enjoy favour over the others in the continuous evolutionary pressure @xcite. here  , i focus on four classes of incoherent feed - forward loops ( icffl ), because they have tendency to produce adaptive responses and they also have uneven abundance in biological regulatory networks . from the level of microscopic cell signalling to nerve conduction, a precise adaptation is unavoidable to keep the sensing outfit functional for further proceedings.the sensitivity amplification and adaptation efficiency of the icffls are quantified by the quantification of mutual information between the network input and output via the mean - field time trajectory at every step increment of the induction and the information is measured at steady state. to remark on the trade - off among the aforesaid tasks in the ic ffls,   pareto optimality is used to evaluate their performance in sensitivity, information processing and adaptation efficiencies in a range of graded induction level. as a result, it is observed that the optimal conditions for the adaptation efficiency and mutual information are found
the ionization of photoionized gas in damped ly@xmath0  systems ( dlas ), which may represent the progenitors to modern disk galaxies, is an important issue for high - precision studies of elemental abundances in the milky way.   the long - held assumption that ionization effects are neglible in these systems may be unwarranted given the observed velocity structure of the absorption lines of low- and intermediate - ions along the sightlines to high - redshift qsos. in this work   we examine the contribution of photosynthetic gas to the observed metal - line absorption in damps using a tracer of moderately ( photo)ionized gaseous gas, al@x Math5iii . by comparing the measured column density of a single ion of a given element, @xmath2, with that of neutral hydrogen, we find that the ionization stages of the warm ionized medium ( wim ) in the dlas  are dominated by singly - ionized species, e.g., tn, nh, and, while the bulk of the system is dominated by neutral hydrogen. however, the formation of metal absorption lines in
the number of small galaxies in the voids is an interesting question for both the observations and the theory to tackle.   the theory predicts that many dwarf dark matter halos should be in thevoids, which puts it in the collision course with observations. here   we use n - body simulations done with the adaptive refinement tree code @xcite to test this hypothesis.. the simulations are for spatially flat cosmological lcdm model with following parameters : @xmath8 km / s / mpc. as a measure of   how large is a halo we typically use the maxumum circular velocity@xmath9, which is easier to relate to observatons as compared with the virial mass. for reference,   halos with @x Math10km / s have virial masses about @x math11 and halos at @x maths12km / g have virile mass about @Xmath13. by comparing the results of the simulations with those of observations, we find that the size of the local supercluster is very close to the limit of the observed distance between the milky way and m31 ( ~1.5mpc ).
xassist is a software package for the analysis of x - ray data.   it is fully automatic and can be run interactively ( with a text - based interface ) or interactively interactively with the command - line ( using the iraf / ftools - style parameter file system ). in this article   we describe the current capabilities of xassist, and discuss its prospects for the future.
gait analysis plays an important role in exploring laws of human motion by gait parameters via biomechanical methods.   the essence of human center of mass ( com ) motion is actually the periodical change which is under the effect of external forces such as, ground reaction force ( grf ), gravity and resistance. to explore the principle behind the gait characteristics, we wish to advance an attempt towards an approach where the precision of the calculation reaches new levels. using analytic and numerical techniques  , we shall identify the action in gait and explore the possibility of the least - action principle in Gait.. the most important issue in this attempt is the prediction of action in a stride cycle with respect to the time of initial foot contact ( tifc ). for this purpose, we present our recent results on kinetic regularities of com and discuss the aspects of determination of the force distribution in transverse, sagittal and frontal planes and optimization of dispersion of force. also, we describe the determination of working parameters, such as acceleration, velocity and displacement of Com and establish the relationships between the kinetic regularity and the tif c in a step cycle. finally, we conclude this section by addressing the effect
the nanoaggregate structure and stability of bitumen nanoaggregates are studied in the stationary regime using molecular dynamics ( md ) simulations.   a master equation and a statistical mechanics model are derived and used to model the results of the md simulations on the nanoaggregation of asphaltene molecules in bitumen. for the first case,   the results show that the probability of having a nanoagg aggregate containing a given number of aromatic molecules is reduced by about 50% when only asphal ten molecules are counted in the nanoagglomerates. for another case, where all aromatic molecules are also counted, the probabilities of having one or more nanoagg aggregates of a given size are increased by about 10-fold. then  , the more complicated case is discussed in terms of statistical mechanics arguments. finally, the limit of our model is discussed.
colliding winds of massive star binary systems are considered as potential sites of non - thermal high - energy photon production, via leptonic and/or hadronic process after acceleration of primary particles in the collision shock @xcite.   we present the results of magic observations of two such systems, wr146 and wr147, which have been resolved using the very large array ( vla ) and the multi - element radio linked interferometer ( merlin ) in two sources each. for both systems,   the colliding wind region was found to be composed of a wn8(h+ ) system with a minimum mass of around @xmath2km / s and an orbital period of ~1.5 yr. at the angular resolution of the magic telescope ( @x Math8 ) the collining wind zone will not appear to be spatially resolved, presenting individual colliding Wind binary systems as point - source candidates at the @x math4-ray sky.    the most detailed model is currently available for wr147, where the system was predicted to be a powerful magic source for most of the orbital period@xcite, while for wr146, the model is based on the presence of
the quantum evolution of a luttinger liquid after an interaction quench is studied in the context of nonequilibrium bosonization.   we show that the dynamics of the system after the quench are controlled by charge fractionalization at temporal ( and possibly spatial ) boundaries of the interaction region and by theNonequilibrium distributions of incoming electrons with multiple fermi edges originating from applied bias voltages. for this purpose,   the energy - law exponents of the fermion - edge exponents and the dephasing rates are determined by the nonequ equilibrium state of the systems. to explore the effects of the input nonequilibration distributions on the power - law correlations, we employ a unified framework of the none Quenching formalism which takes into account the interactions of the two types of Nonequilibrium settings. using this formalism  , we find that the changes in the distribution functions of incoming fermions have a strong dependence on the time scales of thenonequilibrium quench and the zero - bias anomaly caused by the change of the source electrode voltage.
we investigate the ground state of electrons in the fourth lowest landau level ( @xmath4 ) by dmrg method.   we have investigated systems with up to 18 electrons at various filling factors by examining the pair correlation function. for the most filling factors our system is large enough that it is rather easy to tell the ground states by looking at the aspect ration dependence of the energy at fixed filling factors, and the phase diagram of the system can be determined by comparing the results with those of exact diagonalization studies. from these studies, we find that the wigner crystal state is either the stripe state, the bubble state, or the two - electron bubble phase depending on the filling factor and the landau index.
abstractthe nearest observed long - duration gamma - ray bursts ( grbs ) are associated with supernovae ( sne ).   the mechanism behind these events is thought to be the collapse of the stripped core of a massive star to a black hole, but evidence for asphericity is not easy to glean from early - time data. in this review,   we discuss the nebular spectra of sn1998bw, the nearest observed sn associated with grbs, and the effect of the collapse on the evolution of the light curve at the time of the sn explosion.
the atoms held in optical cavities play a vital role in studies of many - body physics using cavity quantum electronic ( qed ) tools.   their high tunability and the possibility of achieving strong light matter coupling or probing the dynamics in real time make them very attractive experimental platforms. here   we present a theoretical analysis of the non - equilibrium physics of a two - dimensional array of identical three - level atoms each coupled to a horizontal cavity mode and vertical cavity mode with the same coupling constant @xmath3, where each cavity hosts a number of atoms. using the effective hamiltonian describing the system in sec. [   model ] we find mean - field equations of motion whose solutions feature rich dynamics, including bistable behaviour, ising like phase transition or the occurrence of limit cycles.
we investigate distributed supervisory control of concurrent discrete - event systems.   we find that the computation of the supremal controllable sublanguage of the specification, from which the supervisor can be constructed, is not possible if the specification is not necessarily decomposable. to address this problem, we introduce the notion of conditional decomposability and present a polynomial - time algorithm to find an acceptable alphabet.
the newly discovered canis major galaxy ( cma ) is a relic of the sagittarius dwarf galaxy ( sgr dsph ), which is currently being observed during its disruption into a giant stream contributing to the continued assembly of the galactic halo with stars.   we present the first detection of the main sequence ( ms ) of the cma system in a wide field located @xmath14 apart from its center, from deep b and v photometry of very recent eso - wfi images taken from the eso archive. using the 2mass database, we have obtained a near infrared ( nir ) colour magnitude diagram of the whole extent of the ring structure of the newly discovered galaxy, which shows a large overdensity of " ring - like " m - giants in the upper rgb of both galaxies.    the results are consistent with the conclusion that the star population of the new galaxy is dominated by stars of similar colour ( m-giants ).. the presence of fainter stars in the central region of the galaxy suggests that the process of hierarchical merging is the driving mechanism of the formation of the monoceros ring structure.
stochastic optimal control is an important research area for analysis and control design for continuous - time dynamical systems that operate in the presence of uncertainty.   however, existing stochastic control methods can not be readily applied to handle complex temporal logic specifications with real - time constraints, which are of growing interest to the design of autonomous and semiautonous systems. in this paper  , we propose a numerical method for stochastically optimal control with respect to a subclass of metric temporal logic ( mtl ) specifications. as the discretization gets finer in both state space and time space, the optimal control policy in the abstract system converges to the optimal one in the original sto chastic system with respectto the probability of satisfying the formula in the _ point - based semantics _ of @xcite.
in the last few years, great progress has been made towards the understanding of the out of equilibrium dynamics of  classical  systems with slow dynamics and aging effects.   experiments in several glassy materials such as polymer glasses, spin - glasses,@xcite orientational glasses, simple liquids like glycerol and gels, @xcite have shown that all these systems share an extremely slow dynamics at low temperatures. to understand the behavior of these systems,   a number of theoretical methods have been employed, ranging from scaling arguments based on coarsening ideas to analytical solutions to models with infinite - range interactions. here   we review the results of these studies and discuss how they have been used to develop a general framework for the analysis of non - equilibrium dynamics in order to explain the aging effects observed experimentally.
neutron scattering is one of the most important tools to determine the structure and dynamics of condensed matter.   one of its major advantages is that the neutron as an electrically neutral probe is not influenced by the electron cloud of the target atoms but interacts only with the nucleus. in this paper   we present results for the ns   static structure factor of a liquid of diatomic molecules, i.e. one ofthe most simple systems in which effects of the molecular nature can be studied. using the representation of @xmath2 in terms of the atomic correlation functions we show that the existence of a prepeak in the static ns  structure factor is closely connected to orientational degrees of freedom.
the quantum amplitude of a gravitational and a massless scalar field is given by a lorentzian path integral for the time separation between the two spacelike surfaces depicted, together with other data at spatial infinity.   the formalism is well adapted to studying strong - field amplitudes, as we shall see in this paper, with the help of numerical analysis. here   we show that the classical boundary - value problem is well - posed for moderate - sized boundary data, and the numerical methods to be described in sec. 2 will test this conjecture.
the influence of the electron - electron interaction on the energy levels and far - infrared ( fir ) spectroscopy of a two - electron nanoring is studied.   we develop a new theoretical method to handle the non - separability of the total hamiltonian for a ring - like confinement potential, which can not be separated into the center - of - mass and the relative - motion terms.. the model is based on the well - known series solution method, @xcite, which is effective to solve the single particle problem, and the exact diagonalization method. in this paper  , we show that the electron- and coulomb - mediated interaction can change the energies of the ground state transition and excitation s properties of the nanoring significantly. by applying the new method,   the interactions between the electrons and the confining potential can be decoupled from the centers of mass and radial motions. as a result, the lower energy levels are intersected at the intersection between the lower levels and the resonance energies are split and dis - continuous drops of the resonances are observed in the near - infrared spectroscopic data. moreover, the generalized kohn theorem breaks down in the fir spect
the renormalisation group technique is used to study the effective average action of qcd reggeon field ( rft ) theory at short and long transverse distances.   it is shown that in both regions we have the same structure : reggeon fields which live in one time ( rapidity ) and two space dimensions, i.e. reggeon energy and transverse momenta. here   we address the following question : can rft be considered as a useful effective description which can be linked to qcd starting from the knowledge of its formulation ( fields and symmetries )?   the tool we are going to use is the renormalization group technique in an essentially wilsonian form, namely, the effective averaging action description for the long distance region @xcite, which allows to investigate the change of the generator of the proper vertices of the theory as one integrates over the ultraviolet field modes. using this analysis we show that the eaa is a non local functional, in the sense that it can not be written in terms of a local lagrangian, exactly as its standard effective action counterpart. on the other hand, we find that the parameters of the regge pole model of donnach
weak and modular values of qubit states feature a geometric representation in terms of three - dimensional vectors on the bloch sphere.   the complex values are expressed using the modulus and the argument instead of their real and imaginary parts. within this approach and the majorana representation,   we demonstrate that an arbitrary weak or modular value of three- and high - dimensional discrete quantum systems can be deduced from geometric quantities defined on the Bloch sphere.see research article http://www.biomedcentral.com/1471-2148/7/9/8
in this paper, the results of the approximate theoretical analysis described in the appendix are compared with our own many - body ( @xmath3-body ) simulations.   one of the goals of the simulation is to test the validities of a modified local criterion for stability of jeans - type gravity perturbations in a self - gravitating, infinitesimally thin and collisionless disk by simulating the evolution of the mean - square velocity of model particles in the system using a sufficiently large number of model stars. because of the fact that the nonaxisymmetric perturbation in the differentially rotating system is more unstable than the axisymmetry ones, the modified toomre - like criterion is used to study the stability of these perturbational effects. as the size of the model system increases, the mean diameter of the jeans - unstable perturbed region increases linearly with time ; the observed behavior is a sensitive test of the proposed model as well as the kinetic theory of stellar disks.
a series of molecular dynamics simulations of spc / e water confined in a silica pore @xcite are presented.   the simulations are based on a model of the pore, which is modeled to represent the average properties of vycor pores. for the simulations the hydration level of the system is taken into account and the single particle dynamics of confined water is discussed in comparison with that of bulk spc/e water.
during the last decades it has become clear that our galaxy ( hereafter, the mw ) is a barred system, as first suggested by @xcite.   now we have good evidence from nir photometry, star counts, gas kinematics, microlensing and dynamical effects near the solar circle. in this letter   we show that a separate inferred  long bar  does not necessarily follow from the star count data, and we suggest a plausible model to explain these data with a single barred structure whose inner parts represent the boxy bulge. also we show some predictions for radial velocity distributions that could be used to test this model in the near future.
we have obtained a raw catalog of differential galaxy counts in the j and ks bands from the eso 3.5 m new technology telescope ( ntt ) with the new infrared imager / spectrometer sofi.   we have extracted different samples by varying the s / n limit in order to optimize completeness and number of spurious detections for a given magnitude limit. at a detection limit of @xmath10,   compact objects as faint as@xmath11 and @x Math12 were singled out in our images, compared with @x math13 and @Xmath14 in the deepest keck observations on smaller areas on the sky previously obtained by other authors. using the data obtained from the ntt deep field, we have deduced that a s/n=155 cut - off seems to ensure the optimum threshold for confident object detection both in j andks within a 0.3 mag accuracy.
hamilton cycles occupy a position of central importance in graph theory, and are the subject of countless results.   the most famous is dirac s theorem @xcite, which states that a hamilton cycle can always be found in any @xmath1-vertex graph with all degrees at least @x Math7. here  , we introduce several new techniques which enable us to prove the first results for packing _ tight _ hamilton cycles in 3-uniform hypergraphs, i.e., those with a fixed degree @x math27.    we focus on the concrete case of 3- uniform hyper Graphs, which we refer to as  3-graphs  from now on. using these methods, we show that one can pack almost all the edges of a given @x maths19-un uniform hypergraph with disjoint hamilton cyclic cycles of a fixed type@xmath20 if the vertices of the hypergraph are ordered in a cyclic order, and if the minimum degree of the graph is set at some point between @x mathematics6 and @xMath6. by taking into account the pseudo - randomness of the graphs, we find
bilayer graphene is one of the most promising candidates to replace silicon as a channel material for nanoscale transistors.   however, state of the art technology can not conveniently control the chirality and the nanotube position, as well as define graphene nanoribbons with widths close to 1 - 2 nm with atomically flat edges, in order to obtain a reasonable semiconducting energy gap. in this letter  , we want to assess the possibility of fabricating a tunable - gap bilayer graphene ( bg ) fet with independent gate operation, based on atomistic numerical simulations. using the non - equilibrium green s function formalism, we have developed a code based on the self - consistent solution of the poisson and schrdinger equations within the negf formalism and the ballistic transport assumption, which has been applied to the simulation of a double - gate bg - fet, whose structure is shown in the case of a monolayer graphene transistors   @xcite. the results show that the proposed device does not meet the it requirements @xcite for the @xmath0 ratio by a large amount, since the induced gap is not sufficient to suppress band
summarythe lyman break technique has been used extensively to isolate galaxies at @xmath0  24 in the hubble deep field north ( hdf - n ). here   we present constraints on the x - ray emission from these galaxies using stacking analysis of data from a recent @x Math4  ms observation of the hdf-n and its environs with the _ chandra X - ray observatory.   our results show that the galaxy population found in the hDF - n itself is dominated by low - luminosity active galactic nuclei ( llagn ), which are not more than a factor of@xmath5 larger than those of spiral galaxies in the local universe. however, we find that the number of llagn within the h df - n is much smaller than expected based on the spectroscopic redshift catalogs of the same galaxy population. as a result, we propose that llagn are likely to be far less luminous than previously thought, and that they may have evolved with redshift due to the changing cosmic star - formation rate.
the existence of highly - irradiated, gas - giants planets orbiting within @xmath6 au of their host stars, and the unexpected large radii of many of them, is an unresolved problem in the theory of planet formation and evolution.   this paper reports on wts-1b, the first planet discovery from the wfcam transit survey ( wts ; @xcite ), which is the only large - scale ground - based transit survey that operates at near infrared ( nir ) wavelengths. using a combination of low- and high - resolution spectroscopic and photometric follow - up observations, we show that the planet is a hot jupiter with a roche lobe radius of ~2.5  km in the orbit of its host star, and a mean mass of ~3.0  km. to understand the nature and peculiarity of this new planet, we use a combined analysis of the observed spectra and measurements of the incident stellar flux and reflex motions of the host star and the radial velocity data collected by the wts as well as the photometric observations of the planet over a period of ~4.7  h. we find that the parent star is a brown dwarf
the star formation rate ( sfr ) of the galactic disk is commonly expressed as a " schmidt - kennicutt " power law function of the surface density of the interstellar gas, even though the physical processes leading to this relation are not yet fully understood.   we have used the spectra of m dwarfs whose spectra show h@xmath0 emission ( dme ) to reconstruct the sfr of the milky way disk in a new, independent manner. using the chemical enrichment history of the galaxy, we find that the sfh of the disk has been declining slowly for the last 5 gyr, prior to which it was rising slowly, and has been punctuated by bursts of star formation from time to time.
we investigate the ground state properties of a single band hubbard model@xcite in the presence of a perpendicular electric field by using the gutzwiller approximation ( ga ).   we show that by applying an electric field, charges will be trapped at the surface of the mott insulator and shift the metal insulator transition(mit ) for the surface states. to address the narrow band effects in transition metals with d or f orbitals for which correlation effects play a major role in the behavior of the system   the simplest model that is able to explain the most important terms of the coulomb interaction between electrons is the well known hubbard models. in this paper   our simplified approach is only qualitative, but it gives important information about how one may be able to spatially tune the quasiparticle weight distribution near surfaces and interfaces.
the purpose of this paper is to calculate the effect of including the turbulent pressure @xmath1, derived from the 3-d radiative hydrodynamic simulations of robinson et al.   ( described in a companion poster paper ), into the hydrostatic structure of the outer layers of the models, where @x Math1 is known to be significant ; and to determine the frequency shift caused by the inclusion of @x math1 on the p - mode oscillation frequencies.the turbulent pressure was calculated for three models of the evolving sun, corresponding to the sun on the zero - age main sequence ( zams ), the present sun, and the future sun as a subgiant. using the 1-d stellar models as starting points, one can derive a new parameter @x maths1, which is used to compute the total pressure, the turbulent energy per unit mass, the mean density and the turbulent vertical velocity in the convection zone.the results show that the turbulence peak in the zams model moves outwards, toward lower@xmath5, as the sun evolves. at the same time, the solar surface convection peaks in the other two models move inward, towards lower @xMath5.
the luminescence properties of si / sio@xmath0 superlattices ( sls ) fabricated by molecular beam epitaxy ( mbe ) have been investigated using transmission electron microscopy ( tem ) and first - principles calculations.   the results show that the luminescent properties of the sls are not determined solely by the confinement of the electronic states within the nanostructures, but also by the nature of the energy gap in the visible part of the spectrum. for a given energy gap of @xmath49 ev, the electrons are confined within the silicon quantum wells, whereas for a corresponding energy gap between @x Math49 and @xMath9 ev, they are confined outside the quantum wells. to investigate the mechanism of the observed blue shift in the optical spectrum,   it has been shown that the absorption of the blue light is due to the formation of a band gap between the two layers of sls.
we introduce a new semantical framework for the analysis of implicit computational complexity.   it consists of an innovative modification of realizability, where bounded - time algorithms are considered as realizers instead of taking plain turing machines as is usually the case in realizable constructions. here  , we show that the concept of a resource monoid and its properties can be used to study the class of representable functions in complexity classes based on logics and lambda calculi.. the main idea underlying our proposal lies in introducing the category of length spaces and studying its properties. given a monoid @xmath1,   the length space is defined as the number of elements of a commutative monoid with a certain time bound to kleene applications of realizers. using this concept, we give new proofs of polytime soundness for light affine logic ( lal, @xcite ), eal, lfpl, sal and soft affine Logic ( sal, @excite ).
the landau - pomeranchuk - migdal ( lpm ) effect, which reduces the radiation emission from an ultrarelativistic electron in a medium due to multiple coulomb scattering, has been investigated extensively at both slac and cern.   however, the question remains if the traditional approach of using migdal s theoretical formulation is adequate in the case of targets of low nuclear charge. since the lpm effect is routinely applied in codes used to interpret extended air showers which naturally occur in a low-@xmath0 medium, the answer to this question is important. here   we report the results of a synchrotron experiment with tertiary beams of electrons with energies of 20 and 178 gev that investigate the kink in the radiation spectrum obtained from migdal’s formula when the bethe - heitler ( bh ) level reaches the @xmath4 level. for the first time  , we show that the calculated spectra obtained from the migdal formula are not sufficiently sensitive to detect electrons with high - energy photon emission, but can be detected by a bismuth germanate ( bgo ) calorimeter with a detection limit of @x
we rediscuss the @xmath0 luminosity function ( lf, hereafter ) of galaxies in the coma cluster, first explored by dml91.   we show that the availability of colors does not help in identifying interlopers and that the field lf can be used to identify galaxies at very high redshift in the direction of the coma clusters. using field counts and the extensive redshift surveys in the same direction, we derive the coma galaxy lf for galaxies at @x Math6.1 km s@xmath8 mpc@x math8, which is in good agreement with the recent determination of the _ local field   _ @xMath0 luminosities for galaxies from the hubble deep field.
we report two candidates of faint stellar companions to the transiting planetary system hat - p-7 based on the subaru hiciao and the calar alto astralux data.   the first candidate is a planet with a highly tilted orbit relative to the stellar equatorial plane ( @xcite ; hereafter nsh09 ), and the second is a brown dwarf with a low - mass companion ( @xmath9 mag. & 9.344 & 0.029 ) around gj  758@xcite. in this paper  , we describe the observations, analyses, and results of the search for these two candidates using the sub Subaru hicao as part of the seeds project ( strategic explorations of exoplanets and disks with subaru, pi : motohide tamura ). although our data alone can not distinguish whether or not the candidate companion stars are physically associated with hat -p-7 at this point, the findings are useful to constrain the mechanism of planetary migration in this system.
the relaxation dynamics of supercooled liquids occur through local particle rearrangements whose energy cost is related to the elastic properties of the material.   these correlations have stimulated the formulation of elastic models of the glass transition, which relate the relaxation dynamics and the elasticity of glass formers. in this paper   we consider the applicability of these models to suspensions of particles interacting via a harmonic potentials, which are of interest as model for the interaction of macroscopic particles such as bubbles, foams and microgels, whose dynamics exhibit glassy features at high concentration and/or low temperature. here  , we show that in finite range repulsive systems the shear modulus estimated from the properties of an underlying energy landscape overestimates the plateau shearmodulus, which implies that the energy landscape properties are poorly correlated with the system s elasticity. however, we do find correlations between relaxation time, diffusivity, plateau sheer modulus and debye  waller ( dw ) factor that are consistent with those predicted by the elastic model of theglass transition.
the qcd vacuum is a non - perturbative system, and makes it difficult to study the physics of the strong interaction.   the nambu  jona - lasinio ( njl ) interaction is introduced as a quark - quark interaction inside the chiral bag model. in this paper, we show that a self - consistent solution can be found with finite quark condensates for the baryon number @xmath4 system by considering not only the scalar channel but also the pseudoscalar channel.. the latter channel is required by the hedgehog ansatz in the pion sector. in order to test the self - consistency condition of the njl interaction, we evaluate the quarkcondensates as mode sums in the chirally bag model without introducing a cutoff. using the new approach,   we find that the value of the single quark scalar condensate is similar to the value observed in the ordinary njl model at distance from the center of the hadron. however, the quarks have a finite value due to the boundary conditions, and the values of the two quark states are different depending on the length scale of the long
the virial mass discrepancy in the dvali, gabadadze and poratti ( dgp ) model of gravity is studied.   the theory proposes that the influence of gravity on the brane is accounted for by including an induced 4-dimensional einstein - hilbert term to the full action. in this model, in contrast to the standard randall and sundrum ( rs ) model, gravity is modified at very long distances. in order to obtain the total mass of a cluster of galaxies, we must add up the masses of all the individual galaxies and use the virial theorem to calculate the mass of the cluster.. however, almost in all clusters the viria mass is 20 - 30 times greater than the mass obtained by adding up the individual masses.    we use the dgp model discussed above to explain this discrepancy in a geometric manner. using the jean s equation and the observational data we find that the radial velocity dispersion in the model is much larger than the radial velocities of the observed data. 	 we also find that there is an alternative way to estimate the virium mass of clusters which can be explained by taking into account the extra terms that appear in
we model a learning scenario as bandits on graphs where the information that is obtained is differential.   we assume that there is an inherent and unknown value per node, and that the graph describes the allowed ( pairwise comparisons ) comparisons. in this case, the query returns a random variable whose distribution depends, in general, on the values of nodes @xmath1 and@xmath2.. since this assumption is restrictive in terms of applicability of the algorithms, we also consider the more general setup where contextual information is observed before sampling the edges. for the sake of simplicity,   our goal is to identify the node with the highest value, a problem that has been studied extensively in the machine learning literature ( e.g., @xcite ). when context is added, the goal becomes to progressively fasten the time needed for identifying a good node for the given user at hand, as more and more users interact with the system.
the central parsec of the galactic center ( gc ) is a region of intense light in the k band.   we have used a new method to study the stellar population of this region using eight point spectral energy distributions ( seds ) for 5914 sources from the eso vlt on paranal, and show that it is dominated by late type stars, rather than early type stars as previously predicted. instead of a cusp, we find a depletion of giants in the very center, as already found by @xcite, for giants with k@xmath912, with the latter confirming our own results spectroscopically only recently.
we test the feasibility of a quasi - universal model of the grb jet, in which the emitted energy of each burst varies as a function of angle from the jet axis.   we find that this model is not able to reproduce the observed break times in the afterglow light curve, or the observed grb luminosity function. using a gaussian structure for the jet, we show that the modeled jet configuration can be used to predict the distribution of the emitted energies of bursts with different opening angles.
gas detectors are widespread for detection, tracking and triggering of charged particles such as muons in nuclear and high energy physics ( hep ).   they are characterized by simple and reliable use, but utmost care must be taken to issues such as properties of gas interaction with materials, gas purification, gas mixture contaminants, etc. a large part of gas muon detectors used in hep operates with mixtures containing the regulated refrigerants as quenching medium in applications where excellent time resolution and avalanche operation are necessary.    the aim of this paper is to discuss some of the important properties of gases for particle gas detectors, to list and summarize basic properties of eco - friendly refrigerants from the literature, to discuss their properties for materials compatibility and safe use, and make a prediction on selected parameters crucial for the performance of gas detectors considered.
the interstellar medium ( ism ) is a diverse and complex plasma that is characterized by the presence of multiple atomic ionization species, molecules, and solid composites.   x - ray high - resolution spectroscopy has recently become an attractive method for the study of the ism as it provides data that are unique and complementary to those gathered with other techniques. in this work, we have developed a new photoabsorption model for the absorption of the interstellar medium based on the latest version of the @xcite tbnew model using a continuum - dominated x - rays source as a backlight and a grating spectrometer. within the model,   the absorption lines and edges of the oxygen and neon k edges and the iron l edge are delineated from the observed absorption features of the low - mass x -ray binary ( lmxb ) spectra using a combination of spectral measurements and density functional theory ( dft ) calculations.. the results show that the proposed model can be used to predict the absorption signatures of the different phases of the Interstellar medium.
trihalomethane ( thm ) molecules are of environmental concern as they are toxic to human health.   the human body adsorbs thms by inhalation and by passage through the skin, but the main contribution to human exposure arises from the consumption of chlorinated drinking water. in this paper   we study how a chloroform molecule adsorbbs on the simplest of carbon materials, graphene. by use of density functional theory ( dft ) calculations we determine the energy gained at adsorption and compare with the adsorbed energies of similar molecules, like methane and tribromomethanes ( chbr@xmath0, also called bromoform ), for which the three halogen atoms are cl or br atoms, respectively. using the first - principles van der waals ( vdw ) density - functional method @xcite, we find that the adsoription energy of chloroforms on graphene is significantly lower than that of other thms, especially those with one or more br atoms.
the quasinormal modes ( qnm ) analysis of black holes is a central tool in the investigation of gravitational perturbations of stars and black holes.   the main purpose of the present paper is to consider the qnm of time dependent backgrounds corresponding to a general vaidya metric, with special emphasis on nonstationary effects, generalizing and further developing the work done in @xcite. as a secondary objective,   we show that our numerical setup can be used to investigate the qnsm frequencies in the case of a vaidyan metric evolving towards a reisser - nordstrm naked singularity.
the ramsey interferometry ( ri ) is an interference technique in which one studies the result of the quantum mechanical amplitudes in different domains where fields are applied.   the ramsey s interferometric technique has so far been used in the context of the study of the phase coherence in atomic and molecular systems. in this paper  , we present a demonstration of the ri in the framework of a macroscopic system like a nanomechanical system. to do this, we use the very long decay time of the mechanical coherence as a measure of the dynamics of the optical mirror.    the results show that the roi is sensitive to any dynamical changes in the mechanical oscillator in the time between which the pulses are off. since our experiment is done with fields in the classical domain, we obtain theoretical results valid in this regime only.
surface induced disordering in the two - dimensional potts model is studied numerically for systems with up to @xmath3 states.   the results show that the surface exponents at the bulk first - order transition depend on the number of states, i.e. the values of the surface critical exponents are nonuniversal and depend on microscopic details like the size of the system.
we develop a general theory of dispersive electromagnetically induced transparency ( eit ) in a thermal uniform gas@xcite by taking into account the higher order dispersive properties of the bose - einstein condensate ( bec ).   we show that at a width of @xmath1, dispersion leads to a small temporal broadening of the pulse which is insignificant for microsecond pulses used in slow - light experiments. however, temporal width of microsecond is the critical width below which dispersion starts to distort the pulse shape.
ultraluminous x - ray sources ( ulxs ) are known to be powered by accretion onto black holes.   however, their luminosities, assuming isotropic emission, are higher than the maximum seen in galactic black hole binaries, suggesting the presence of intermediate mass black holes with masses of @xmath4 @xmath5 @xcite or super - eddington accretions onto stellar mass blackholes of about 10  @x Math5 @xaite. here  , we report a new xmm - newton observation of ngc 247, a nearby spiral galaxy in the sculptor group, in the 0.3 - 2  kev band with an unabsorbed luminosity of ~3.4  mpc. using near - infrared observations of cepheids, we show that the source is a very bright, off - nucleus x -ray source with a soft thermal component with @x math6  =  1.8  keV @xcites and a strong star formation rate estimated to be about 0.1  at ~0.2  yr@x maths5. on the basis of these results,   we propose that the
quantum memories for light are a crucial tool for quantum information processing, quantum computing, long - distance secure communication and scalable networks.   the description of the light - atoms interface is usually based on a three - level @xmath1 configuration, with two ground states and one excited state @xcite. however, the hyperfine interaction in the upper states of alkali atoms is not strong enough for the system to be perfectly described by this approximation. in this paper, we show for the@xmath0 optical transition how an additional level significantly modifies the stimulated raman process and we finally evaluate the efficiency of pulse storage and retrieval in this configuration.
we study the low - frequency dynamical response of non - interacting classical superparamagnets.   we derive an approximate expression for the nonlinear susceptibility which is in good agreement with the exact ( continued - fraction ) solution of the fokker   planck equation. exploiting its non - trivial damping dependence,   the equation could assist in obtaining the damping coefficient in these systems.
compton and inverse compton scattering play an important role in the processes of emission of x - ray spectrum which has been observed in many compact astronomical objects.   the problem of the structure of a model atmosphere and the spectrum formation under the influence of very hard x - rays external irradiation is not satisfactorily solved in the present literature. in this paper   we have developed a new method for the solution of the transfer equation of compton reflection by using kompaneets equation and polarization of hard radiation with @xmath11. to find the time evolution of a given initial soft x -ray spectrum due to comptonization in homogeneous medium  , we have used the monte carlo method and obtained few solutions analytically for the time progression of the spectrum with respect to the origin of the initial spectrum from the soft x-ray region for continuum.the proposed method is based on the calculation of the escape probability and the energy distribution of the single scattered photons as well as the photon escape time distribution and the effect ofComptonization on the spectrum. at the same time, the time delay due to photon diffusion and the release of energy from the excited state and the multiple scattering of X - ray
we consider a pair of identical hard disks of finite size accommodated in a circular cavity where each disk is assumed to bounce elastically with its partner and with the boundary wall, but otherwise show a ballistic motion.   although the system is circularly symmetric, it is nonintegrable and chaotic thanks to the ( short - range ) interaction between the disks. by using two - particle wave functions, we evaluate expectation values for the distance between disks, which will elucidate a physical mechanism for fluctuations in the quantal equation of states.
a fundamental problem has been raised by the evidence for multifractality in some solar wind quantities ( e.g. @xcite, and references therein ) and the @xmath0 index.   this would imply that the hurst s  roughness " exponent from the solar wind poynting flux is not constant but varies from scale to scale. here   we present a new model of fractional lvy motion which is based on the scaling collapse of the increments of the time series of the auroral electrojet index ( @x Math0 ) and its solar wind proxy, the@xmath1 function. when compared with some of the measurements listed above, it is shown that the model provides a good quantitative explanation for the difference between two scaling exponents first noted in this context by @xaite, as well as a possible qualitative explanation for their multifractal behaviour. where relevant, the effect of the truncation ( finite variance ) implicit in the model is also discussed.
inflation is a natural consequence of quantum gravity.   the standard model of particle physics ( sm ) requires the existence of a higgs field with the same properties as the inflaton field driving inflation in many models. here   we consider a different scenario in which the total amount of inflation is not much more than 60 e - foldings and the onset of inflation violates the slow - roll assumptions, as the primordial power spectrum is not scale invariant.
the ability to predict or anticipate future events is crucial for the survival of animals.   predicting dynamical inputs can compensate the latency during information transfer and provide predictive information for learning and behavior. in this work, we report our experimental results in quantifying the predictive properties of a retina by using the predictive information ( pi ) method mentioned above. with a retina plated on top of a multi - electrode array ( mea ) probed by stochastic light pulses,   the predictive dynamics of the retina is measured as a function of the properties of the light pulses ; namely its mean inter - pulse interval ( @xmath2 ) and correlation time (@xmath3 ). here  , we show that the location of the peak of the predictive dynamic of the retinas can be shifted from @x Math4 to @x maths5 by an increase of @x math3 ; suggesting that the retina has the ability to prediction ( with some uncertainties ) future events in the stimulation when the stimulation is regular enough. however, this ability of prediction can only be observed when @xMath2 is in the range of 100 ms < < 200 ms ; similar to that of the omitted stimulus response ( osr ) phenomenon
we present a new study of the radio spectral properties of high - frequency selected radio sources from the pilot 20  ghz survey ( at20 g ), which was undertaken with the australia telescope compact array and the very small array ( vsa ).   the results show that the majority of the sample is dominated by flat - spectrum sources, while the fraction of steep - spectrum ones increases with decreasing flux density.  in particular, the spectra of sources with cold - mode accretion of cold gas have steeper radio spectral indices with respect to the sources that accrete hot gas, suggesting that the radio emission in these sources is dominated as a function of the temperature of the accretion jet axis.
the source of cosmic rays with particle energies above @xmath3 ev is still unknown.   models of origin, acceleration, and propagation must be evaluated in light of the observed energy spectrum and chemical composition of the cosmic rays. in this paper  , we review the results of experiments that have attempted to determine the mean cosmic ray composition through the " knee " region of the spectrum, up to @x Math4ev@xcite.. the fly s eye experiment has reported a changing composition from a heavy mix around @x math0ev to a proton dominated flux around @Xmath5ev @xcite ; the agasa experiment shows broad agreement with this trend if the data are interpreted using the same hadronic interaction model as used in the fly's eye analysis @xaite. while the recently reported hires / mia@excite hybrid observation on the cosmic ray composites in a narrower energy region, @x maths6 ev, shows a general agreement with fly’s eye experimental result, the new result gives a somewhat more rapid change in the composition.    the reliability of these experimental results depends on how well we understand the development of all components of extensive air showers ( eas ) produced by
the influence of a background polyakov loop on the properties of topological excitations in the confined phase of calorons has been studied in detail in the semi - classical approximation  @xcite.   it was observed that the one - loop correction to the action for configurations with a non - trivial asymptotic value of the Polyakov loop gives rise to an infinite action barrier, which were therefore considered irrelevant. here   we show that this is not the case and that the monovalent nature of the action is due to the existence of monopole constituents ( also called dyons ) at the center of the gauge group. when added to the perturbative contribution of the polyakov loops at center elements,   a local minimum develops where the trace of the mono - loop vanishes, deepening further for decreasing temperature.see research article .
the cosmic veto counter ( cvc ) is a scintillator that can detect neutrons emitted from the muon - stopping target of the comet experiment.   it is important to know how neutrons affect the cvc, since they could cause fake veto signals in the detector and damage silicon photo - multipliers ( mppcs ) to be used in the shield. here  , we present simulations of the effects of neutrons on the performance of the foil shield of the @xcite cosmotechnological research center for the study of muon registration efficiency at the comet phase - i. the simulation has shown that fast and medium - energy neutrons traversing 7 mm thick polystyrene interact predominantly elastically with each other, leading to production of charged projectiles  protons and carbon ions  that deposit their kinetic energy mostly through ionization causing scintillation in the scintillerator. by taking into account the cost of materials, convenience of construction, and affordable outer size the shield,   the optimal configuration of the shield is of arched shape, which accounts for signal attenuation along strips, and better protects mppc that are located at outer ends of strips.
summaryclusters of galaxies are key targets for studying the evolution of galaxies and large - scale structures.   however, at high redshift ( @xmath10 ) only few clusters have been identified due to the challenge of discriminating a distant cluster from the abundant foreground galaxies. in this paper   we present first results from a pilot study of the quasar 3c270.1 at @x Math0, combining our _ spitzer space telescope data with @x math2- and@xmath3-band maps of the entire 3cr sample of radio galaxies and quasars using the instruments irac ( 3.68.0@x maths1 m, fazio et  al., 2004 ) and mips ( 24@x mathematical 1 m, rieke et al.,   2004 ). based on these maps, we identify a cluster of massive ellipticals and dusty starbursts around @xMath0 that show strong emission from a hot intra - cluster medium.    the cluster is composed of an excess of giant elliptical galaxies with a redshift of 0.624  km / s / m2 and a mean age of 4.5  years.
the bakamjian - thomas construction of the dynamical representations of the poincar group in the presence of strongly interacting few - body systems is a generalization of the sokolov construct @xcite, which provides a means for constructing quantum mechanical models of systems of interacting particles with a finite number of particle degrees of freedom.   this construction is particularly useful for systems of three - nucleon systems, where the system is embedded in a four - particle hilbert space, and where the problem is solvable. here  , we show that the construction can be extended to systems of four - nucleons or electron scattering from a three -ucleon system, and that the restoration of cluster properties can be achieved through a recursive construction due to the skolov construction @xcites.. the reconstruction of the cluster properties is achieved by using a hierarchy of unitary transformations, each of which preserves the @xmath0 matrix while transforming tensor products of subsystem representations of its poincare representations to representations where the interactions can be added in a manner that preserves the underlying poincars symmetry.
we study the effect of a tunnel barrier on the joint distribution of the scattering matrix @xmath1 at the fermi level in a superconducting quantum dot ( andreev billiard ), which determines the thermal and electrical conductance.   we find that the tunnel barrier has no effect on the density of states in the circular unitary ensemble ( cue ) and circular orthogonal ensemble ( coe ), but it does affect the joint distributions of the time - delay matrix ( cre ) and the diffusion matrix ( dm ) for the single - channel case ( @x Math20 ).. the effect is more pronounced for the system with a bound state in the quantum dot, a so - called majorana zero - mode or majorana bound state.
the @xmath10-jets process at the lhc top - quark menu is one of the most important processes in top - physics.   it is well known that the rate of top - pair production is dominated by the semi - leptonic decay of a produced pair of qcd jets, where up to two jets might be heavy - flavor tagged. here   we present a new method for predicting the next - to - leading order ( nlo ) of the @x Math10- jets process using the monte carlo event generator sherpa. with the help of the mcfm code @xcite,   the calculations are performed in the framework of the cdf@xcite program and the results are compared to data from the tevatron and lhcs top - particle physics programme.
the quantum rabi model, one of the fundamental models in quantum optics, describes the light - matter interaction between a quantum two - level system ( atom, qubit ) and a bosonic field ( optical mode, microwave mode ).   the jaynes - cummings ( jc ) hamiltonian can be reduced into weak- and strong - coupling cases under the rotating - wave approximation, i.e., the counter - rotating ( cr ) terms in the interaction can be omitted, and the model can be solved analytically with simple functions. in this paper, we propose a practical approach to manipulate the ultrastrong - coupling regime in the quantum rabi model by introducing a monochromatic modulation of the transition frequency of the quantum 2-level system. using this approach, we show that the enhanced cr interactions in the jc regime can induce stronger photon emission from cavity vacuum state than that in previous studies.
in this article we present a method for reconstructing the field theory from the excitation spectra of topological defects in the inflaton field.   we first outline the recipe for the reconstruction and then explicitly work through two specific examples with kinks in 1 + 1 dimensions. when there is only one bound state ( the translation mode ) on the kink, we obtain the sine - gordon field theory using the implicit expressions of the eigenvalues of the bound states. when the kinking has two bound states, we get the @xmath0 field theory. in inflationary cosmology, we discuss the reconstruction problem in the inflationary context and then qualitatively discuss the bound state spectrum on kinks made from the inflatom field. in particular, we look for signatures of the flatness of the infloton potential in the spectrum.
the star iktau is an extremely red mira variable with an unusually late spectral type ranging from m8.1m11.2 @xcite.   we have observed the very long baseline interferometry ( vlbi ) observations of the @xmath0, sio maser emission toward ikktau using the very large array ( vla ) and the vlba correlator operated by the national radio astronomy observatory ( nrao ) in socorro, new mexico on 1996 april 5 from 20:00 to 24:00 ut. based on a period of 470 days@xcite and a maximum at jd2439440 @xaite the stellar phase of iknau was @x Math20.85 during the epoch of our observations.    the radial velocity of the gas in the circumstellar envelope of ktau was measured using the sio masers located close to the star using a continuum calibrator ( 0423 - 013 ) and a single 4-mhz ( 27.8kms@xmath4 ) band centered on the local standard of rest ( lsr ) velocity of 34.0kms
linear positive systems have been recently the subject of an increasing attention because of their natural ability to represent many real - world processes such as, among others, communication networks, biological networks, epidemiological networks, disease dynamics, etc.   the goal of this paper is hence the derivation of novel stability and stabilization conditions for linear positive impulsive systems using the concepts of arbitrary, constant, minimum, maximum and range dwell - times. in order to obtain these conditions,   a series of time - dependent lyapunov functions are derived from the concept of mode - dependent quadratic lyapUnov functions. by applying these functions to the complex conditions of @xcite, it is shown that they can be used to formulate stability conditions that are both linear / convex in the matrices of the system and independent of the decision matrices driving the disturbance input to the state and the output of the System.. the results are compared with those of the existing literature on the stability of linear positive switched systems.
the two - user discrete memoryless cognitive interference channel ( dm - cic ) is an interference channel that consists of two transmitter - receiver pairs, in which one transmitter ( the cognitive user ) knows the message of the othermitter ( the primary one ), in addition to its own message.   the capacity of this channel remains unknown in general ; however, it is known in several special cases, both in the discrete memorylessness and gaussian channels. in this paper  , we consider the dm-cic and show that there are two different less noisy cognitive channels : the _ primary - less - noisy _ and the  cognitive -Less - noisy   cognitive channels. then, we propose two inner bounds for these channels ; one based on superposition coding, and another one using independent coding. obviously, these inner bounds are also valid for the less noisy dm--cognitive interference channel ; in fact, one of these inner limits is more suitable for the primary - Less - noisy than the other one.we also prove an outer bound on the capacity from the current state of knowledge for the secondary receiver. finally, we show that for the cognitive - lesser - noisy dms, the inner and outer bounds
hopf algebroids are robust generalization of groups.   the author tries to describe the geometry of hopf alges over @xmath3 using algebraic geometric and spectral theoretic methods. in this paper  , he introduces a new structure closely related to a hopf category, which has not appeared in the literature as far as the author s knowledge. for completeness, we also give a short exposition on the representation theoretic and galois theoretic aspects of hop f algeroids.
the ` lock and key'concept has been central to understanding the specificity of biochemical molecular interactions, from enzyme - substrate relationships to antigen - antibody matchings.   however, it has gradually been realized that such a'lock and keys'concept is not strictly valid, particularly in immune systems. here  , we propose a new dynamics of specificity evolutions based on jerne s network hypothesis @xcite. using the standard idiotypic network model, we show that specific and non - specific responses to an antigen are governed dynamically by a fixed point attractor and a chaotic long - lived transient state of an immune network, respectively. at high levels of antigen,   the specificity of the immune network diverges dramatically, but at low levels, the network specificity stays stable. for example, when the number of antigen stimulations is about 9.5 units, the specificity abruptly diverges to a high value. at lower antigen levels, however, the frequency of specificities increases rapidly, whereas at higher antigen levels the frequency remains constant. this process is characterized by a chaotic transient state with a short - lived equilibrium between the two states, which can be explained by a dynamic transition from a transient state to a fixed
graphics processing units ( gpus ) have been a surprise to the scientific community.   they are now making computational inroads against traditional multicore graphics processing cores in many areas of statistical computing, including image processing, protein folding, stock options pricing, robotics, oil exploration, data mining, and many other areas. however, statisticians have been slow to embrace the new technology. here  , we illustrate how gpus can work hand in glove with the mm algorithm, a generalization of the em algorithm, which explicitly separates parameters by replacing the objective function by a sum of surrogate functions, each of which involves a single parameter. because gpus are designed to operate on short streams of data, they can be used in optimization problems that require both separation of data and separation of parameters.
quantum turbulence ( qt ) is a key to understanding turbulence.   it is a topological defect characteristic of a bose   einstein condensate and is different from a vortex in a classical viscous fluid because its circulation is quantized and conserved, in contrast to a classical vortex whose circulation can have any value and is not conserved. since quantized vortices are well defined as elements composing a turbulent flow, qt is expected to be an easier system to study than classical turbulence ( ct ) and has a simpler model of turbulence. here  , we review recent developments in quantum fluid dynamics and qt in superfluid helium and atomic bose - e Einstein condensates.
the faint object spectrographraphraph ( fos ) on the _ hubble space telescope _ ( hst ) has been used to observe the eclipse of the eclipsing dwarf nova ip  peg ( @xmath4  h. ) on 9 occasions between 1992 november and 1994 october.   we report here on the results of our analysis of the first observation, which was carried out on run  1 during ingress to eclipse rather than during the eclipse itself. in this observation,   the system was in a quiescent state at the time of the peak of the pre - eclipse hump and the bright spot was found to be located at the impact site of the accretion stream with the outer edge of the disk. using ground - based photometry, we have determined the blackbody temperature of the hot disk+white dwarf around the star that is expected to be the cause of the flickering observed in the fos observations. from these measurements  , we conclude that the onset of eclipse is approximately one week after the bright Spot hits the impact sites of the mass transfer stream.
the magnetic and electric response of aharonov - bohm rings coupled to a superconducting lc resonator is studied.   the magnetic response is related to persistent currents in the zero frequency limit @xcite. on the other hand the electric response is associated with the screening of the electric field inside the metal.. the non - dissipative part of the flux dependent electric response ( magnetopolarisabilty ) is measured by measuring the induced charge displacement at the origin of the polarisability, defined as the ratio between the induced electric dipole and the applied electric field. for both types of response   we find that the electro response is more sensitive to the screening length and the sample size than the magnetic one.
the association between solar activity and indian monsoon rainfall has been studied using the continuous wavelet transform method with the morlet wavelet function.   seven annual area - weighted rainfall time series for the period 1871 - 1990 have been considered for the analysis, namely, all india summer monsoon precipitation ( aismr ), north east india ( nei ), northwest india(nwi ), central north east India ( cnei), west central india-(wci ), peninsular india- ( pensi)and the homogeneous indianmonsoon ( him ). as it is well known that the nei region shows in many ways an anti - correlation with the him region, we present more detailed results specifically for these two regions. to test the hypothesis that solar activity can be used as a proxy for the variability of the indian Monsoon,   the sunspot number index and group sunspot numbers have been used as indicators of solar activity over the same period, and the relationship between them and the rainfall data has been analysed.    the results show that the mean annual rainfall from the he region shows a strong positive correlation with both the sun spot
charm quarks are believed to be produced at early stages in relativistic heavy - ion collisions and their production cross - section can be evaluated by pqcd  @xcite.   charm energy loss, highly sensitive to the properties of medium, can be inferred by studying the nuclear modification factor of its semileptonic decayed electron. here   we show that charm quark energy loss is a function of the number of binary scaling and intermediate @xmath6 electron decays. for the first time  , we find that the nuclear modifications of charm electrons / muons from weak decays of charmed hadrons in au+au collisions are more pronounced than those of leptons.
the energy loss of hard partons propagating through the soft medium created in heavy - ion collisions has long been regarded as a promising tool to gain information on the medium properties @xcite.   we present a monte carlo simulation for the hard parton s interaction with the medium, as this is an appropriate framework to account for all the above mentioned effects.we assume that the medium can be characterized as a thermal gas of quasi - free quarks and gluons and that it can be treated as incoherent processes in leading - order plasmonic quadrupolecd ( pqcd ). using a hydrodynamical model of the medium produced in ultrarelativistic collisions, we show that the mean free path of hardpartons becomes infinite once the medium temperature drops below the critical temperature @xmath6. given the local@xmath4 temperature, the distribution of scattering partners is given by the fermi - dirac ( bose - einstein ) distribution for quarks ( gla ) and quuons ( q ) respectively. also we estimate the uncertainties of such a computation.
a recent experiment of gaspard et al.   ( @xmath0 ) purports to show that the diffusion of a brownian particle is due to microscopic chaos. here   we explore the question of what kind of experimental measurements or data analysis might be required to identify microscopic chaotic dynamics, and the connection between microscopic chaos and diffusion. in particular, we consider generalizations of models of diffusion due to lorentz and ehrenfest, where a single point particle undergoes elastic collisions with a fixed arrangement of circular or square scatterers in two dimensions, respectively. for each of these three models,   the mean square displacement of a particle is proportional to the time, and we find that the distribution of particles satisfying the diffusion equation is nonchaotic if the model is a finite system with periodic boundaries. by comparing the results of the experiment with those of previous simulations using non - chaotic models, we conclude that no experimental proof of microscopic chaos has been found.
in the last 50 years, filtering has been mainly studied in the framework of state space or hidden markov models, assuming a markovian time evolution of the signal and observations.   this paper gives a brief introduction for non - specialists, explaining the main algorithms, describing their scope and also their limitations and surveying some of the interesting current developments.
graph models have been used in image analysis for a long time, but approaches from quantitative graph theory such as graph indices have not played a significant role in these applications so far.   this is to some extent surprising as it is not a far - fetched idea to model information contained in small patches of a textured image by graphs, and once this has been done, graph indices with their ability to extract in a quantitative form structural information from large collections of graphs lend themselves as a promising tool specifically for texture analysis. the present paper continues the work begun in @xcite where a set of texture descriptors that combine a construction of graphs from image patches with well - known graph indices was introduced that combines a synthetic example of a texture discrimination task with a real - world example of texture - based image segmentation using the geodesic active contour method. in this paper,   the construction of the graph - entropy - based descriptor set is detailed, and two synthetic examples that represent typical realistic texture segmentation tasks are demonstrated on two different synthetic examples and aReal-world example. also, theoretical analysis is presented in relation with fractal dimension measurements on a metric space derived from the pixel graph, and thus a connection is
local molecular field ( lmf ) theory is a new approach to the treatment of electrostatics in biomolecular simulations.   it provides a general conceptual framework that permits a qualitative as well as quantitative understanding of the effects of long - ranged coulomb interactions on local water structure  something that is often obscured in black box application of lattice summation techniques.    we show that lmF theory can be used to correct for the errors in the accuracy of spherical truncations of coulomovalent interactions in nonuniform environments, such as near lipid bilayers, by introducing an effective electrostatic potential @xmath5 that accounts for the remaining effects of the long - range interactions. using gaussian - truncated ( gt ) water from the extended simple point charge ( spc / e ) model of water, we demonstrate that the inclusion of this potential into the calculations required to achieve accurate minimum image simulations of water in non Uniform slab environments is the sole modification of the current state - of - the - art molecular dynamics simulations of gt water.
the @xmath1 is the slowest reaction of the mg - al cycle.   the @x Math6 ground state ( t@xmath7 = 6.35 s ) decays via @x math9 and ec to the @Xmath10 first excited state of @x maths11, which is followed by the emission of a 1.809 mev @xMath12-ray, one of the most important lines in #xmath12 astronomy. since the direct observation of this radiation from comptel @xcite and integral @xaite instruments provides an evidence that @x mathematician6 production is still active on a large scale, it is necessary to determine the rate of the decay of the ground state @xometh6 to the new ground state at the level of e@xmathemat2 = 304 kev. here   we report the results of a monte carlo code based on geant4 simulations of the resonance strengths down to the resonance energy at e@ xmath2 = 189 kev using the ams technique for the generation of isotopically enriched @xmeth6 with a proton beam current of 100na and a nai summing crystal @xc
we investigate the near - threshold regime of bosonic three - dimensional @xmath1-body clusters, i.e., the regime where the critical coupling constant for each cluster becomes unbound.   we perform precise diffusion monte carlo calculations for clusters interacting additively through realistic shape - dependent two - body van der waals potentials. using a single channel approximation, we describe weakly - bound three - dimensionally bosonic clusters with varying atom - atom scattering lengths with up to @x Math0 atoms. in particular, we study the behavior of super - borromean clusters, which consist of three bosons for which each dimeric subsystem is unbound and for which all subsystems with mass@xmath11, where @x math12, are unbound, and compare with variational bounds obtained from previous studies. by applying a numerical approach to solving the many - body schrdinger equation, we obtain more accurate energies for a large range of coupling strengths and for a larger range of cluster sizes than previous studies ( e.g., up to ~2.5 atoms ). our results for the energetics and structural properties are presented in secs.
labelled transition systems are a fundamental modelling formalism in many areas of computer science and one often needs to compare two or more such systems in applications.   this paper unifies several strands of established work in one integrated framework : metric semantics of processes ; use of hennessy - milner logic, domain theory and transition systems ; means of under - specifying and refining processes ; and representations of classical topological spaces as maximal - point spaces of domains. using a domain @xmath0, defined in @xcite and shown to be a universal model for finitely - branching modal transition systems and fully abstract for their refinement in loc, we show that the maximal - points space of the fully abstract domain of section   is a stone space and the quotient of all labelled transition systems with respect to bisimulation is the right conceptual space for reasoning about and comparing quantitative aspects of these systems.
metallicity - sensitive indices for globular cluster stars have been devised from photometric and low- to medium - resolution data in order to study large samples of clusters.   these indices require calibration to high - resolution abundance analyses of , which are usually based on the equilibrium of the local thermodynamic equalibrium ( lte ) between fe  i and fe  ii. however, new developments in the abundance analysis of metal - poor giant stars have led to the development of new scales of colour versus t@xmath4, and new cluster distance moduli based on _ hipparcos_ ( esa 1997 ) parallaxes for nearby subdwarfs. here  , we discuss the effects of these developments on the metallicity scale of globular clusters.
a new paradigm for variational inequalities for set - valued optimization problems is proposed, based on the concept of optimal solutions.   it is shown that the existence of a solution to such a problem implies some regularity property on the primitive optimization problem. under certain regularity assumptions  , it is proven that the solutions of the minty type inequality are weak minimizers of the set optimization problem and that the corresponding weak minimizer of the vector variational inequality solves the stampacchia differential variational equality. under convexity assumptions on the scalarizations,   the reverse implications have been proven.  in addition, a chain of implications has been provided for minimizers, actually for solutions of set optimization problems, and the corresponding minty and stampac chia type inequalities.
we extend the standard model(sm)-like higgs boson to include two component non - baryonic dark matter ( dm ) candidates.   the first component is a scalar singlet and the second one is a vector fermion field, both of which can interact with the sm through higgs - portal. in order to improve the fine - tuning problem, the new fields entering into the veltman condition should be bosonic fields which provide positive contributions. on the contrary, the fermionic fields give negative contributions thus making the problem worse. by considering both the scalar and vector as dark matter candidate, we find that the number of scalars @xmath15 is set to be larger than@xmath16 through direct detection constraint, i.e., xenon100 experiment. using allowed parameter space, we revise thefine - tuning, unitarity and the vacuum stability of higgs Boson.
the unidirectional movement of a single motor along protein filaments is well characterized experimentally and it was first modeled at a microscopic level by a stochastic dynamics describing the behavior of a brownian particle in the presence of a time - dependent asymmetric potential field.   more recently, it appeared in the literature attempts to describe the movement of interacting brownian motors, since it was realized that collective effects emerging from this situation may be relevant to explain certain characteristics of cellular transport and, in particular, the observed property of bidirectionallity of cargo movement. here  , we make a proposal in this direction based on considerations about the interactions between cargo and motor molecules : the arrival of a cargo particle may perturb the motor system in such a way to produce local changes onto the existing motor density. thereafter cargo may take advantage of the local changes induced by this initial perturbation to move along microtubule by '' surfing _ at the density shock waves formed as the motor systems relax back to the situation before interaction.
we study the non - zero values of certain momentum correlations of the @xmath0 leptons decay products  @xcite.   these correlations are non - vanishing in the event that a dipole moment form factor ( wdm ) or an electric dipole form factor for the@xmath2 lepton has an edm or a weak wdm, which are expected to be unobservably small in the standard model ( sm ). since there is no cp violation in the quark sector in the sm, it would be unambiguous evidence for physics beyond the sm if significant cp violation occurred in the production of @x Math0 leptic pairs, or in their decay @xaite. here   we present estimates for the wdm and edm in some popular extensions of the sm where complex couplings can easily generate cp - violating dipole moments for @x math0 lepta at one - loop order.    we also study the effects of helicity - flip bremsstrahlung on these correlations using the proposed tesla linear collider.
the discrete nonlinear schrdinger ( dnls ) breather is a vibrational mode in anharmonic lattices which is generally linearly stable close to the uncoupled limit.   however, when considering time - scales large compared to the breather period, the mere linear stability of a breather does no longer guarantee its eternal existence in the presence of small perturbations, and there are still many questions remaining concerning the different mechanisms by which breathers may grow or decay, or possibly finally be destroyed. here  , we investigate in more detail some mechanisms for breather growth and decay in a simple model system, the discrete quasiperiodic nls - breather, using numerical investigations using standard floquet analysis. as a result of the stochastic nature of the breathing,   it is possible to estimate the life - time of the Breather with high accuracy, and to find out whether the breathing is spontaneously created from noisy background conditions or is generated by the modulational instability of travelling plane waves occurring in the lattice. on the basis of these results, we propose that the breathing can be considered as a process of self - localization, and that the rate of breathing depends on
we have studied the large scale mass distribution around the richness class  1 cluster abcg 85, using x - ray and optical observations.   we find that abc g 85 itself exhibits preferential alignments on scales from 100 kpc to @xmath6mpc ( projection on the sky ). in particular, the cluster cd galaxy is elongated along the same position angle as a large filamentary structure in x - rays roughly coinciding with the optical position of abcG 87. located to the east of abcsg 85   is abcgs 89 and 87, which are not detected as extended X - ray sources. based on these results, we propose a model for the formation of the abcge 85/87/89 complex.
we study current - induced dynamics of a composite free layer ( cfl ) with antiferromagnetic rkkyne exchange coupling in metallic spin valve pillars.   we consider a system @xmath0/@xmath1/@Xmath2/#@x Math3/##{xmath4/$xmath5 }, where the cfl structure is composed of two magnetic layers separated by a thin nonmagnetic spacer, and the spacer layer is usually thin so that there is a strong rky exchange coupling between magnetic layers. using the model described in refs.  and   , we show that the critical current required for switching a synthetic antifermagnet ( syaf ) free layer from a simple sensing layer to a synthetic ferrimagnet(syf ) freelayer is reduced by about 50% when the interface between the two free layers is an antiferomagnetic layer. however, the reduction of critical current in the case of Antiferromagnetically coupled cfls still remains an open problem.
the field emission or cold emission is an electron emission process induced by strong external electric fields at zero or extremely low temperature.   the theory of field emission from bulk metals was first proposed by fowler and nordheim in an epoch making paper in the proceedings of royal society of london in the year 1928 @xcite. here   we review the current knowledge about the field emission processes from metal surface.
the @xmath4dropout galaxy spectra of hdfff  d16 and hdf4 - 555.1, the hotdog  shaped galaxy in the hdf, are aligned in their rest frames at keck with the lris spectrograph.   the emission and absorption strengths of the redshifted lyman limit spectral discontinuity ( ly@xmath1 ) as well as the growth of the stellar, stellar  wind, and ism absorptions are shown to be strongly correlated with the metal abundance levels of the surrounding gas and dust.
cosmic @xmath0-ray bursts ( grbs ) are brief flashes of cosmic high energy photons that occur in the sky every year.   they are detected by instruments somewhat similar to those used by the particle physicists at their laboratories, but the difference is that grb detectors have to be placed onboard balloons, rockets or satellites. in spite of the abundance of new observations of grbs,   their energy source and emission mechanism remain highly speculative. here   i review all the efforts in the search for grb counterparts throughout the electromagnetic spectrum from the time of the konus experiment on _ veneras 11_ and _ 12_ to the present day. during the last decade  , there has been a huge increase in the number of experiments devoted to the study of grb - like phenomena. among them, the most important ones are the studies of the soft x - ray range, which is characterized by transient emission of x - rays in the order of 20 - 40 kev below the maximum energy of the bursts. with the advent of new spectrometer - based experiments, it is now possible to observe grb events at lower energies than 20 kev, with the aim of understanding the nature of the
the ring - like patterns observed in the outer parts of ( pre-)planetary nebulae ( ppn / pn ) of asymptotic giant branch stars ( agb stars ) and their remnant material are often attributed to the periodic mass loss of a single star in the previous agb phase, due to stellar pulsation or thermal pulsation on the spherically symmetric wind.   however, it is not generally recognized that the binary - induced spiral - shell pattern in the circumstellar envelope of a mass losing star @xcite, vertically extended from the orbital plane, exhibits an inclined viewing angle, such that the outer part of the spiral approximates a concentric ring structure. because of the incompleteness of the observed ring - Like patterns, whether they arise from spherical shells due to the pulsation of single stars or spiral -shell patterns due to binary orbital motion is inconclusive.. in this paper, we propose that the incomplete ring -Like patterns observed for the outer rim of the ppn/pn may be caused by the motion of ( unknown ) binary stars.    linking a binary scenario with the ring -like patterns observed on the circumstellar envelopes of as
the time it takes a quantum system to complete a tunneling event is a much less well - defined notion than the probability for quantum tunneling.   it is often hard to measure in experiment and in many cases still the subject of intense debate. in this paper   we address the problem of measuring the timescale associated with one of the conceptually simplest tunneling phenomena, landau - zener ( lz ) tunneling, which arises when two energy levels of a quantum systems cross as a function of some parameter that varies in time.    we show that the tunneling time can be defined as the time after which the lz jump time reaches its asymptotic value in the time - resolved tunneling probability. from this definition   one can expect to observe a step - like structure, with a finite width, in the distance between the ground and excited states of the system at the time of the avoided crossing. because the step is not very sharp, it is not possible to measure the time scales of the transition times associated with lz tunneling experimentally. using the two - state model of eq.   (  where the off - diagonal term, @x
the classic model for galaxy formation within the cold dark matter ( cdm ) paradigm assumes that gas within galaxy halos is shock heated to the virial temperature as it accretes onto galaxies.   this assumption has been routinely adopted by many analytical works, but recent theoretical work has found that the majority of baryons may never reach the virium temperature as they accrete onto galaxies @xcite. here   we examine how gas gets into galaxies using a n - body + smoothed particle hydrodynamics ( sph ) simulation of a cosmological volume simulated with an adaptive mesh refinement ( amr ) code. in the presence of a shock,   cold gas accretion is dominated by filaments in the cosmic web, and is not shock heated during the collapse of the halo ; instead, it cools onto the galaxy on a free fall timescale rather than being shock heated due to the cooling rate of the gas behind the shock. given a density profile, a cooling radius can be calculated, inside of which gas can radiate away its energy while conserving its specific angular momentum to form a centrifugally supported disk that grows from the inside out. when a galaxy is in the low
globular clusters in extragalactic systems have established themselves as powerful diagnostics of the star formation history, dynamics, and structure of their host galaxies.   however, information on the globular cluster systems of late - type galaxies is sparse. here  , we present an imaging study of two edge  on spiral galaxies ( ngc 4565 and ngc 5907 ) that have been searched for globular clusters by harris, bothun & hesser ( 1988 ), but no globular clustering has been detected. using wfpc2 images of the two galaxies, we show that the observed number of clusters is a function of the distance and luminosity of the galaxy, and that the specific frequency of these clusters is very similar to that of the well - studied milky way globular Cluster system. under the same assumptions, we find that the cluster specific frequency for ngc4565 is about 1.5 times higher than that of ngc5907.    the results of the present study are consistent with the predictions of the merger model of the formation and evolution of elliptical galaxies.
the unfolding pathway of a macromolecule is the order and the way in which the structural blocks of the molecule unravel.   recent studies have shown that the pulling velocity plays a relevant role in determining the unfolding pathway @xcite. here  , we develop a physical theory that predicts the observed dependence of the unfolded pathway on the pulling speed. by means of a perturbative expansion of the asymmetry of the free energies and the pulling rate, we show that for low ( high ) enough pulling speeds, it is still the weakest ( pulled ) unit that unfolds first, but other pathways are present for intermediate velocities. moreover, we discuss the role of thermal noise and the ( ir)relevance of the details of the device controlling the length of the protein.
we study the possibilities for investigating the behavior of qcd pomeron effects in photon - photon scattering at @xmath2 colliders, where the photons are produced from the lepton beams by bremsstrahlung.   we find that the total cross section of the off - shell photon scattering can be measured at high energy by measuring the momenta of the outgoing leptons and the photon virtualities. using a five - fold differential cross section parametrize  , we show that this cross section can be expressed as a function of the number of events that are available for investigation at present and future linear @x math9 colliders.. the results are compared with those of previous studies on the structure functions for deeply inelastic scattering off a proton and jet production at large rapidity separations in hadron - hadron collisions.
quantum optimal control theory ( qoct ) is a powerful tool for calculating the optimal shaped pulse to maximize a desired physical objective ( or minimize a physical cost function ).   it has been applied to various open quantum systems or models to obtain control sequences for quantum gate operations @xcite. in this paper  , we present an efficient qoct approach based on the krotov optimization method to deal with time - nonlocal non - markovian open quantum system problems. by introducing auxiliary density matrices in an extended auxiliary liouville space,   the time - ordered non - commuting integro - differential master equation of the quantum brownian model is transformed into a set of time - local coupled differential equations. as a result, incorporation of the resultant time - Local equations with the k rotov optimization algorithm   becomes effective. using this approach, we find that the optimal quantum gate control sequence for a qubit in a non - markedovian environment ( bath ) with long bath correlation times ( long memory effects ) can be found to be the same as the optimal qoct control sequence given by the gradient optimization method@xcite.graphical abstract
non - equilibrium electron properties on time scales of 10 - 100s of femtoseconds are most efficiently observed with pulsed laser measurement techniques.   the two - temperature model ( ttm ),@xcite, is widely used to describe the thermal non - equilibrium between electrons and the lattice in plasmonic nanostructures. however, a complete _ ab initio  description of the time evolution and optical response of this non - equilibration electron gas from femtosing to picosecond time scales has remained elusive, especially because of the empirical treatment of electron - phonon interactions. here  , we show that the ttm can be used to accurately predict the transient optical responses of metal nanostructure by accounting for the electron - temperature dependence of the electronic heat capacity, electron - pharyngeal coupling factor and dielectric functions. using our calculations of the electron and lattice heat capacities, @xmath5 and @x Math6, we find that the peak electron temperature,@xmath8 is only accessible in repeatable measurements if the equilibrated lattice temperature is less than the melting temperature of the metal,@xaite which yields the condition @x
a basic problem in database theory is the computation of the probability of a ( boolean ) query over a probabilistic database in polynomial time, even for fixed queries in simple syntactic forms.   jha and suciu recently studied the compilability of queries whose lineages have small circuit treewidths into decision diagrams, ordered binary decision diagrams ( obdds ), where every path from the root to the leaf visits the boolean variables in the same order. here  , we extend this study by studying the compilageability of these queries into discrete classes of deterministic decomposable circuits that are more tractable as obdds but more succinct than the ones with bounded circuit pathwidths.
the analysis of cosmic large - scale structure in the distribution of galaxies contributed significantly to establish the current cosmological concordance model.   however, the available and upcoming galaxy redshift survey data can not merely be characterized by its two - point correlation properties. for higher orders, however, there are computational and conceptual challenges. on the computational side,   measuring all pairs in current surveys is feasible, for all triangles there are methods to do it @xcite, but beyond that it becomes increasingly hard. from the conceptual side, even if measuring the full @xmath7-point function was possible, it would require modeling and covariances for a large number of data bins. already for a modest number of bins   for each parameter of the @x math7-points function, this is a challenge.. therefore, it is worthwhile to consider other approaches that contain information on certain aspects of the higher - order clustering without referring to the full correlation functions. here  , we use minkowski functionals to analyze the high - order distributions of the sloan digital sky survey ( sdss ) data release seven ( dr7 ) luminous red galaxies ( lrgs ) in@xcite
we report on a series of high resolution ( 1.7 ghz ) observations of the relativistic jet m87 with the nrao  x - ray observatory at 1.667 ghz.   the observations reveal dynamic structures within the flaring x -ray region of the jet, including the discovery of superluminal motion in multiple knots and the emergence of a radio knot moving downstream from the upstream edge of the inner jet.
recent observations taken as part of the hi parkes all - sky survey ( hipass ) reveal several exciting new features of the magellanic clouds.   the single dish 21-cm observations allow us to examine the large scale structure of the lmc, the overall spatial and velocity distribution of the smc and bridge gas and resolve the long - standing controversy about the mechanism responsible for the formation of the Magellanic stream.
the x - ray spectrum of the cas  a supernova remnant ( @xmath5arcmin ), obtained using all the narrow - field instruments on board the bepposax satellite, is discussed.   the spectrum is modeled as being due to two distinct plasma components, i.e. the ejecta from the supernova explosion and the shocked surrounding circumstellar medium. in the present paper   we use the non - equilibrium ionization ( nei ) plasma emission codes to model the source spectrum at the resolution of the low energy concentrator spectrometer ( lecs ) and the three medium energy concentrate spectrometers ( mecs ), the high - pressure gas scintillation proportional counter ( hpgspc ), and the phoswich detector system ( pds ). for the csm component, the emission from the ejected remains of the parent supernova   is assumed to be the hotter one, and for the ejectA the cooler one. by combining the data from the lecs and mecs detectors, we show that the temperature of the hot ejecta is much lower than that of the cooled csm, and that the mass of the shocked csm is much higher than that
the inner 1  kpc region contains a large population of discrete luminous radio sources presumed to represent primarily a population of radio emitting starburst galaxies ( snr ). here   we present a report of the first search for satellite oh maser line emission at 1720 mhz and 1612 mhz associated with this snr population using the very large array of the national radio astronomy observatory.   these masers are probably associated with pumping by collisions with h@xmath6 molecules in snr shocks, in accordance with the models by elitzur ( 1976 ).
the isospin physics of hot protoneutron and cold neutron matter is well constrained to a small range @xcite within a relativistic mean - field ( rmf ) model.   the symmetry energy at the normal nuclear matter density, @xmath9, has been previously constrained to about 0.2 mev for a neutron - rich system with respect to asymmetry :@xmath11. in order to understand the composition and structure of stars over this extreme density range, it is important to know the density dependence of nuclear symmetry energy. here   we explore the effects of symmetry energy in the rmf model, that has been limited to a narrow range from analysis of skin data, on the composition or structure of both hot prot one - electron and cold two - electron neutron matter that encompasses a large density range. using a newly born neutron star as a model model, we find that the symmetric nuclear matter equation of state, @Xmath12, can be constrained to ~0.5 mev at subsaturation densities and that the ratio of proton to neutron asymmetry is the leading coefficient of an expansion of the total energy for a neutrino - proton symmetry energy for
we study the late - time evolution of the gravitational collapse of a massless charged scalar - field on a reissner - nordstrm background.   the results are compared with the predictions of the linearized perturbation theory, which predict the existence of oscillatory inverse power - law tails along the asymptotic regions of future timelike infinity, future null infinity and along the future outer - horizon with _ smaller ( compared to the neutral case ) dumping exponents. in this paper   we show that the late-time behaviour of the fully nonlinear gravitational collapse is in excellent agreement with the prediction of the analytical analysis.
the spectra of the merger seyfert galaxy arp 220 ( z=0.018 ), which is an ultraluminous infrared galaxy ( ulirg ) with @xmath3 10@xmath4, at a distance of 72 mpc, are analysed by modelling the spectra by models which account for the photoionizing flux from the agn and from the starburst coupled with a shock wave hydrodynamic regime.   the results show that the optical line spectra are better reproduced by the AGn, while the ir line ratios are explained by the starbursts. in the present paper   we will investigate the physical conditions and the abundances of the heavy elements throughout the n of close sey fert galaxies which show merging, as was done for e.g. ngc 7212, contini et al.    ( 2012 ) and ngc 3393 ( 2012a ) on the basis of the observed spectra.
the recent discovery by choptuik and others of new and unexpected critical behavior in gravitational collapse has sparked efforts, both numerical and analytic, to understand the nature of the black hole scaling relation, and how the observed echoing arises out of the einstein equations.   this paper returns to the gravitational collapse of a massless complex scalar field in spherical symmetry, as a good theoretical laboratory in which to address these issues. here   we derive a new continuously self - similar chOptuon at the threshold of black hole formation, and construct the complete spacetime. the discrete echoing seen in the original choptucite @xcite reappeared as continuous phase oscillations of the complex scalary field. however, the choptus by itself does not yield the blackhole scaling relation ; one needs to perturb the ch Optuon.    this paper considers only spherically symmetric perturbations, the relevant ones for eq. ( [ bhmass ), and the most likely ones to be unstable. using a nonspherical perturbation analysis of any of the known Choptuons, we find that the most probably unstable ones are the ones with the critical exponent @xmath
the existence of gravitational waves ( gws ) in astrophysical compact objects has been the subject of intense debate for more than 50 years.   the discovery of the kerr solution describing rotating binary systems of supermassive bh ( bh ) binaries and the identification of the first observed x - ray binary with an ordinary star have provided strong evidence for the existence of bh sources. here  , we review the current state of the art in the field of gravitational wave astronomy, and we discuss the recent advances in our understanding of the physical nature of these sources.
stellar observations network group ( song ) is an initiative started in denmark to create a global network of highly specialized 1 m telescopes aimed at doing time - domain astronomy.   the goals are to produce exquisite data for asteroseismic studies of stars across most of the hr diagram ( with focus on solar - like stars ), and to search for, and characterize, the population of low - mass planets in orbit around other stars via the microlensing and radial  velocity methods.a ground - based network with a sufficient number of nodes will ensure observations with a high duty - cycle, needed to obtain stellar oscillation spectra with high frequency precision and without aliasing problems. furthermore, the light - curve anomalies in microlense events occur at unpredictable times and thus, to find and characterize these, near - continuous observations are needed.the group behind song has obtained funding for the design and construction of a full prototype network node which shall be completed in late 2011. in the following   we describe some of the aspects of the ongoing work and the expected performance of the prototype.
we present a markovian master equation for the decoherence of spontaneously formed schrdinger - cat states in the anharmonic potential.   the master equation takes into account the fact that in a general an Harmonic system the relaxation rate of each energy eigenstate is different, and it is found that the reduced density operator that arises due to thedecoherence can be identified with a mixture of states that are well - localized in the phase space and equally distributed along the orbit of the corresponding classical particle. using this master equation, we show how the phase portrait of the system reflects the damping of revivals in the expectation values of the position and momentum operators by the effect of the environment on the wave packet motion in the morse potential. also, we calculate and plot the time evolution of the wigner function corresponding to the reducing density operator of the Morse system.
the susceptibility propagation ( susprop ) algorithm has been derived to infer couplings of sherrington - kirkpatrick ( sk ) model from synthetic data of hopfield networks.   the performance of susprop on the reconstruction of the hopfield network is compared with other existing mean field methods and a threshold behavior relative to susprop is observed in the retrieval phase. at low temperature,   it is found that the inference error with sampling from single basin of the stored pattern is much similar while error with sample from multiple basins is drastically reduced. at high temperature, the quality of reconstruction is constrained by the implementation precision of the algorithm and the random noise embedded in the supplied data.
the time spent by a quantum particle passing through a potential barrier has been one of the most controversial questions since the founding of quantum physics.   there are various approaches dealing with tunneling time@xcite, but there has been no clear - cut answer to this old question. in the present paper   we revisit the larmor precession of a neutral spinning particle with a general spin coherent state as a clock to measure the tunneling times through a barrier and extend for the first time the study of quantum tunneling to the relativistic regime. with the help of the equation of motion for the expectation value of spin operator in the magnetic field within a barrier,   the time - independent magnetic field * b * is used to calculate the l armor precession time of a nonrelativistic and relativismic neutral spin 1/2 particle with respect to the barrier height. using the spin coherent states of two different spin operators in the magnetically confined region of the barrier, we find that both nonrelatevistic and relativity - related spin particles perform a simple l Armor precession in three - dimensional space. when the barrier is confined to the region where the spin of the particle is in the
we have studied the light propagation of a probe pulse in a four - level double lambda system, where the applied laser fields form a closed interaction loop.   the system consists of three atomic states in ladder configuration, with an additional fourth perturbing state coupled by a laser field to the upper state of the ladder system. using a weak incoherent pump field, we find that in the region around a narrow structure both sub- and superluminal propagation as well as negative group velocities are possible in the ultraviolet region. for the first time, we show that the medium susceptibility in dependence on the probe field detuning exhibits high - contrast structures characteristic of interacting dark resonances, i.e., high - frequency waveforms characteristic of absorption - dependent light propagation.
scanning tunneling microscopy ( stm ) has been considered the most important technique to image, control and monitorize molecular systems with atomic resolution under a wide range of experimental conditions that enable molecule visualization.   the quality of stm images is, however, limited by various degradation mechanisms including noise, drifts, and dropouts. in this paper, we present a new method for image denoising using sparse regression, often termed sparse coding. following the standard procedure in patch - based image restoration, the image is partitioned into small overlapping square patches and the vector corresponding to each patch is modeled as a sparse linear combination of vectors, termed atoms, taken from a set called dictionary. aiming at optimal sparse representations, and thus at optimal noise removing capabilities, the dictionary is learned from the data it represents via matrix factorization with sparsity constraints on the code ( i.e., the regression coefficients ) enforced by the @xmath0 norm  . the sparsity of a representation on a dictionary is strongly linked with the level of self - similarity of the images under study. compared with the standard approach,   Stm images pose an additional challenge : they have plenty of artifacts, mainly dropouts,
stochastic resonance ( sr ) is a powerful tool for studying stochastic dynamics in biomolecules.   sr is a maximum in the response of a biomolecule to an external force at a characteristic frequency ( the resonance frequency ), which is triggered by the oscillation of the molecular extension relative to the magnitude of the noise produced by the external force.. we investigate sr in single dna hairpins driven by oscillatory mechanical forces using optical tweezers and compare different sr quantifiers that measure the resonant activation of the hopping kinetics between the folded and unfolded states. when force oscillates around the average unfolding force, the thermally activated hopping kinetic synchronizes with the frequency of the external driving force, leading to sr. here  , we show that sr can be used to identify the hopping rate in short dna sequences that exhibit bistable dynamics, rather than using sr as a useful tool to determine the kinetic properties of these molecules. however, we also show how sr might be useful to enhance the detection of conformational transitions of low snr.
in particle physics there is a number of well - established principles ( four - dimensional lorentz invariance, renormalizability, gauge symmetries, etc. ), which are believed to underlie a consistent quantum field theory.   all these principles are built into the standard model ( sm ) and its great experimental success is a major justification for their validity. in continuing search for the consistent description of an emerging physics beyond the standard models, one often tries to ease some of these criteria. among many possible extensions of the standard Model   there are theories with extra dimensions, where zero modes of both matter and gauge fields are localized on the 4-dimensional defect, called brane - world models. here   we review the current state of knowledge about the properties of these models and discuss how to distinguish between them.
the friction of sliding gold nanocrystals with a triangular lattice symmetry  on a triangular or hexagonal substrate ( such as graphite ) is investigated systematically theoretically.   the friction is investigated analytically through the total potential energy of the contact layer on the substrate, which is modelled with a realistic static potential. for perfect crystals there are three types of ( in)commensurability and consequently three possibilities for the scaling of the friction with the size of the surface area @xmath0, namely@xmath7, ~7, and ~0.1  mm2. for imperfectly and irregularly shaped nanocrystal surfaces, the friction scales with contact size, depending on the orientation, and conclusions are drawn from this regarding commensurate and incommensurate orientations. also for contacts between crystals with rectangular lattice geometries, it is found that the interfacial friction is of the order of @x math4, with the substrate period and the potential energy corrugation of the interface being the most important factor.
the green - schwarz anomaly cancellation mechanism for the kalb - ramond anti - symmetric tensor field in @xmath1 dimensions is discussed.   the application of this mechanism to the @x Math0 dimensions is also discussed, and the possible effects of wormholes are discussed.
the hypothesis of the existence of new spatial dimensions has been proposed as a solution to the hierarchy problem in particle physics.   the modified newtonian dynamics ( mond ) theory is postulated to be valid for accelerations below a certain threshold, @xmath4 1.2 cms@xmath7, which is determined empirically to be about 1 mm. here   we propose that the same experiments can be used to test for a similar prediction of deviations, suggested by the mond theory, suggesting that the strong equivalence principle should be relaxed and that this hypothesis should be tested in the laboratory.
this paper builds a parallel theory for directed weighted networks in an annulus.   we show that the space of edge weights of networks in a disk can be endowed with a natural family of poisson brackets that " respects" the operation of concatenation of diagrams. under postnikov s parametrization,   this family induces a two - parameter family of Poisson brackets on the grassmannian. every poisson bracket in this family   is compatible ( in the sense of @xcite ) with the cluster algebra on the Grassmannian and, on the other hand, endows it with a structure of a poisson homogeneous space with respect to the natural action of the general linear group equipped with an r - matrix poisson - lie structure.
we introduce a four - level asymmetrical coupled - double gaas / algaas semiconductor quantum wells ( qw ) system with intersubband transitions in the conduction band, which has been realized in the latest experiment @xcite.   we demonstrate the implementation of the two - qubit controlled - phase gate as well as the creation of maximally entangled state and propose a practical experiment to discriminate the maximally entrained state of theTwo-qubit through discriminating two out of four bell states.
the opera experiment  @xcite is the first direct observation of the appearance of @xmath3 from @x Math4 oscillations in the atmospheric sector using the long baseline ( l=730 km ) cngs neutrino beam @xcite from cern to lngs, the largest underground physics laboratory in the world.   the experimental design and operation of the opera experiment have been described. for the first time  , data were collected by the opera detector still without emulsion cloud chamber ( ecc ) bricks installed, yielding a preliminary measurement of the beam features along with the collection of a number of neutrinos interactions ( 319 ) consistent with the integrated beam intensity of 7.6 @x math6 10@xmath7 protons on target ( p.o.t. ). during the first run of the experiment   there were no significant differences in the energy profile of the beams between the two sets of detectors ; however, the performance of the scintillator tracker detector was slightly lower than expected due to the use of lead / emulsion - film ecc modules.
we present data from the same keck observing run as georgakakis et al.   ( 2000 ) for two additional galaxies, ngc 1052 and ngc 7332, which reveal signs of a recent merger or interaction between two gas  rich galaxies. in both galaxies   the red globular cluster ( gc ) subpopulations are indigenous and the blue ones are acquired. to determine the age and metallicity of the red gcs we use spectroscopic techniques to determine their ages and metallicities. here   we show that the age of the young gcs is determined by the bimodal color distribution of the blue and the red clusters. using this method we find that the old gcs are older than the young ones and the new ones are younger than the old ones. however, the difference in age is not statistically significant.
quantum computing is one of the most promising areas of quantum computing.   quantum dots are semiconductor quantum dots that trap electrons in discrete energy - levels, energetically isolated from the semiconductor environment, resulting in excitonic ( electron - hole pair ) transitions with an atom - like light - matter interaction that can be used to control the spin states of the dots. here   we propose and demonstrate the sequential optical preparation, control, and detection of a single hole spin trapped on an ingaas / gaas quantum dot using a picosecond laser pulse with a pulse - area of @xmath1, and waiting for the electron to tunnel leaving a spin - polarized hole. by controlling the spin state of the hole,   it is possible to initialize the hole spin state, and detect the hole when the hole is in the correct position in the dot.
we propose a solution method for combinatorial optimization problems based on a two step search procedure that interleaves subproblem generation and subproblem solution.   we solve a relaxation of the problem at the root node and we use reduced costs to rank domain values ; then we partition the domain of each variable in two sets, i.e., the _ good _ part and the _ bad _ part. by using a strategy imposing on the left branch the branching constraint@xmath6 while on the right branch we impose @xmath7, we obtain a subproblem which can now be solved ( in the _ sub Problem solution tree _ ). exploring with a limited discrepancy strategy the resulting search space, we obtained that the first generated subproblems are supposed to be the most promising and are likely to contain the optimal solution. moreover, even by using low cardinality good sets, * we almost always find the best solution in the first generating subproblem*. thus, reduced costs provide extremely useful information indicating for each variable which values are the most suitable for generating promising subprobles.    this property of reduced costs is independent of the tightness of the relaxation.
a mobile ad - hoc network ( manet ) is comprised of several mobile devices connected by means of short - range wireless links, in which each device is a router for other devices as well as being an end host.   self - organization in manets provides efficient solutions for building large distributed systems, in order to manage the network without the guidance of an external source. in this paper, we present a new simulation platform, called abmq, which is based on qt and is suitable for modeling and simulation of self-organizing algorithms in complex networks, and particularly manets. using an agent - based approach,   each participant device makes up a manet, where autonomy is the most important characteristic of participants. while simulating the infrastructure level algorithms, the application level algorithms can be simulated at the same time. furthermore, it provides many useful features for reusing the codes and models developed over the simulation process in orderto build real third - party applications.
the electron - doped high-@xmath4 superconductors are less well - understood than their hole -doped counterparts @xcite.   however, experiments on la@x Math1ce@x math2cuo@x maths3  ( lcco ), pr@xMath1ce#@x mathematics2cao@x mathematician3  and nd@x mathematical 1ce@Xmath1ce*@x mathematic 2cuo<xmath3 (ncco)+ ) have great significance in the field of condensed matter physics because they provide a way to investigate particle - hole symmetry in the phase diagram where superconductivity emerges from doping a highly correlated antiferromagnetic mott insulator or charge transfer insulator @xcites.    although there are many similarities in the generic phase diagrams of hole and electron -Doped cuprates, there are also considerable differences @xaite. in particular, the magnetism is much more prominent on the electron - Doped side and appears to overlap significantly with superconduction in both the electron- and hole - dope cuprates. here   we show that these differences are due to the fact that
we report the results of a systematic survey of the galactic plane using the low - energy concentrator spectrometer ( lecs ; 0.110  kev ; parmar et al.  , @xcite ) and the medium - energy Concentrator spectroscopy ( mecs ; 1.810  ks ; boella et al.., 2014 ) on - board bepposax in the region of sky around @xmath14 between 1999 july 20 11:59 and july 21 02:05  utc. during this period, we observed 479 events of x - ray pulsar emission from a new source 71 off - axis from the inner edge of the mecs window support structure with a count rate of @x Math17  s@xmath9 for both mecs units. to better assess the significance of these peaks, a lomb - scargle periodogram was generated. at 437.1  s,   the strongest peaks were found at a period of 437  s and at twice this period ( 874  s ), with  values of 42 and 34, respectively, for 8 degrees of freedom ( dof ). by contrast,
the ehrenfest time is the time it takes for the chaotic classical dynamics to stretch an initially narrow wave packet to some relevant classical length scale such as the system size.   in recent years, there has been much interest in determining the influence of the ehren fest time on stationary transport quantities such as conductance, its variance and its behavior under decoherence, shot noise and higher moments of the current @xcite.    most of these papers used the trajectory - based semiclassical approach to transport @xcites which currently is the method of choice for investigating ehrenFest - time dependences of quantum observables @xcitons. in this paper, we determine semiclassically the eh Renfest - time dependence of the variance @xmath11 of the conductance for a chaotic system coupled to external leads via nonideal contacts modeled by tunnel barriers of transparency.. the presence of tunnel barriers has the dramatic effect that @x Math11 increases or decreases with @x maths0, depending on the value of @x math3. for @xMath4  , we even observe an enhancement of the variability above the universal value in the absence of time reversal symmetry for equal lead widths of @
we present a detailed study of the quantum ising chain in a transverse magnetic field @xcite in the presence of magnetic fields coupled with the order - parameter spin operator, located at the boundaries of the chain.   we assume the two magnetic fields to have the same strength and consider two cases : ( i ) the two fields are parallel ; ( ii ) the boundary fields are oppositely aligned. for small magnetic fields,   the ground state is ferromagnetic as it occurs in the absence of boundary interactions. on the other hand, kink states@xcite are the relevant low - energy excitations for large boundary fields. because of the q - to - classical mapping, our results can also be applied to the two - dimensional ising model, and, more generally, to any model in the ising universality class, in a strip geometry.see research article http://www.biomedcentral.com/1471-7007/9/8/11
we derive a kinetic equation for dense quantum plasmas in strong electromagnetic fields using the random phase approximation ( polarization approximation ) for the particle  particle scattering processes.   our approach is based on the nonequilibrium green s functions formalism which allows for the most straightforward derivation and for an explicit solution of the gauge problem. by means of this approach,   we derive a generalization of klimontovich s classical result for the case of zero field and static field as well as generalizations for the polarization and screening properties and longitudinal field properties of dense nonideal plasms in intense laser fields.
we report on near - infrared observations of the perseus molecular cloud at moderate column densities ( a@xmath0 @xmath1 30 mag ) and relatively high galactic latitude. in these deep images ( complete to j = 20.1,   h = 20, ks= 19.3 ), there is pronounced emission structure associated with the clouds.   this diffuse structure, or " cloudshine ", is well explained by scattering of the diffuse interstellar radiation field by dust grains with the optical properties of @xcite.
the goal of targeted vaccination is to identify the individuals that are potentially most important for disease spreading, then use this information to vaccinate ( or otherwise reduce the impact ) them.   the goal of this paper is to address the trade - off between effectiveness and efficiency of vaccination protocols. in an uncorrelated random network,   one can vaccinate randomly selected individuals, rather than asking them to name someone they met, but does not vaccinate those who have not been vaccinated. in this paper  , we find that the randomized protocols ( _ acquaintance _,  random walk ,  two - step heuristic  and  tsh  ) outperform the _ random _ protocol as well as the three protocols, which require the knowledge of the entire network, including vaccinating the top - degree nodes.
the polarization of continuum radiation in the mid infrared spectrum of comet hale - bopp c/1995 o1 was measured using the t - matrix code.   the polarization data were obtained from a polarimetric data base of 22 comets, which has been used to study the characteristics of the cometary dust grains. for the first time  , the results obtained from the t-matrix code have been compared with those of the discrete dipole approximation ( dda ) method, where the polarization of the scattered light by the grains is determined by the scattering angle and the shape and size of the particle. based on the results of the experiments,   it is concluded that the particles are mostly porous and irregularly shaped, and they are not spherical in shape.
deep x - ray imaging of crowded fields is invariably limited by the small number of source counts and by the relative size of the point - spread function ( psf ) compared to the angular separation between the objects.   a superior source - detection method is needed for severely crowded fields containing multiple faint sources, e.g.  globular cluster cores @xcite, or nuclear bulges in external galaxies. here  , we re - visit the characteristics of the kolmogorov   smirnov ( k - s ) test in two ( and three ) dimensions and examine its power in comparing different realisations of crowded low @xmath0 fields. as an application of the test, we devise an iterative source - modelling scheme that aims to minimise the k-s statistic in search of the optimum underlying source distribution in an image. based on our monte carlo simulations, we find that our iterative algorithm is a powerful tool for faint object searches in crowded fields.
the analysis of ( @xmath4 ) reactions at photon energies above the giant resonance was the object of a long debate concerning the mechanism of the reaction.   the experimental cross sections for proton emission can be easily fitted with a single particle wave function to a direct knockout ( dko ) mechanism, but the results are very sensitive to the theoretical ingredients adopted for bound and scattering states. in this work   we use a fully relativistic distorted wave impulse approximation ( rdwia ) framework to analyze the experimentally measured cross sections of the (@xmath5 ) reaction using data obtained at the electron microtron accelerator mami - a in mainz and at the max - laboratory in lund under tagged photon conditions. by incorporating the contribution of meson exchange currents ( mec ) into the framework of dko  , we show that the model is able to reproduce the measured cross section for the low - lying states and in the photon energy range above the Giant resonance and below the pion production threshold, but is unable to explain the high - energy region below the threshold for the quenching of the proton - nucleus elastomeric transition from the intermediate to the excited state.
the photon anomalous magnetic moment is a property of the quantum vacuum in which it propagates in the presence of an external magnetic field.   it was shown by schwinger@xcite that electrons get an anomalousmagnetic moment due to qed radiative corrections in presence of a magnetic field, and that the same property was obtained @xcite in the vicinity of the threshold for positronium creation. in this paper   we show that the photon also exhibits such anomalous Magnetic Moment due to its interaction with the virtual electron - positron pairs in the magnetized vacuum where it propagation. from the general solution of the dispersion equation of the polarization operator we analyze the interaction term and define a magnetic moment of the photon. in the strong magnetic field limit for the photon and the photon-positronium mixed state when both particles are created in the landau ground state,   the second mode of propagation is found, since in the realistic conditions of production and propagation of @xmath9 quanta the third mode decays into the second modes via the photon splitting process.
the same - side  ridge " in two - particle correlations produced in very high - multiplicity proton - proton collisions at the large hadron collider ( lhc ) is an unexpected finding by the cms collaboration.   we suggest that a similar ridge effect may be at work in the high multiplicity @xmath12 collisions, albeit with a quite different physical mechanism. if we think of a proton as three quarks bound by color forces, then a plausible description of the binding involves color flux ` strings'or tubes connecting to each quark, and to each other, like the bisectors of a triangle with the quarks at the vertices (  y " diagrams ) diagrams, which are natural in the higher fock states of the light - front wave functions of the proton. for the collisions of interest  , we need the projection of the flux tube onto the  impact - plane ", and well over half of the linear configurations should survive this projection. on the head - on collision of two such configurations, we find that the overlap would be significant only for one of the two gluons near one end of the tube, and not for the other.
we study the equilibrium behavior of a symmetrically diluted hopfield model with finite connectivity and low - activity units in q - ising states.   we consider explicitly a @xmath0,@xmath1 and a continuous @x Math2-state network. for each state,   the synapses are diluted by a small number of synapses and the activity of the embedded patterns is low.    we find that the memory retrieval performance of the network is reduced by a large number of spin - glass - like states in the region where they compete with the retrieval states and that the size of the basins of attraction of the memory ( retrieval ) states is increased in the network with a low storage ratio. to explain why this is the case, we show how the hamiltonian becomes the sum of an effective hopfield - model hamiltonia and the effect of synaptic noise is taken into account.
the realisation of gaseous atomic bose - einstein condensates ( becs ) from @xcite has sparked intense theoretical and experimental interest in the area of experimental atom - optics.   we have developed a soft curved temporal magnetic mirror that can be used to reflect, focus and store atom laser beams from a low - power double magneto - optical trap ( mot ) at the low pressure end of a single diode laser beam using cold atoms as an atomic mirror. here  we give a more detailed description of our ` simple'bec apparatus, followed by benchmarking experiments that were performed on the diffraction and focusing of a bec from the mirror. for the first time  , we demonstrate the effect of the mirror potential on the refocusing and bouncing of a condensed bec from a high pressure trap laser beam with a temperature of ~20 k. we also compare and contrast the effects of two different theories of atom - optical manipulation : the theory of experimentally attainable situations and the model of quantum degenerate regimes.
magnetic reconnection takes place while topologically distinct regions approach each other and the magnetic field lines change their connectivity.   the standard setup involves the violation of the ideal magnetic field theory ( mhd ) approximation on the boundary between neighbouring magnetic domains where the field direction changes rapidly. in this paper   we examine the structure of the magnetic fields twisted by a highly curved spacetime of a rotating black hole ( bh ), and show that the magneto - rotational instability operating in the inner regions of the accreting bh systems creates conditions favourable for reconnection.
the electrostatic coupling of charged macromolecular surfaces with mobile counterions is a fundamental issue in the field of charged ( bio)colloidal systems.   the traditional approach to charged systems has been the mean - field poisson - boltzmann formalism, which is applicable at weak surface charges, low counter - ion valency and high temperature. however, the limitations of this approach become practically important in highly - charged systems where counterion - mediated interactions between charged bodies start to deviate substantially from the means - field accepted wisdom. here   we present a new method for the systematization of these non - pb effects based on the notions of  weak  and  strong  coupling approximations.. the model system is characterized by the presence of a quasi - two - dimensional counterion layer next to a charged surface that is much larger than the separation between two neighboring counterions in solution and thus behaves basically as a three - dimensional gas. using the netz - moreira coupling parameter @xcite, we show that the strength of the coupling between counterions depends on the charge valency of the counterions and the distance at which they interact with the charged surface. when the counter
we present a monte carlo model of a target - searching game on a two - dimensional bond percolation on an underlying square lattice.   the active hunter is trying to find out a target which emits a special kind of odor by randomly moving its head from side to side to test the variation of the odor intensity. since neither the distance nor the direction of the target is presumedly to be known, the searcher should determine its moves by random attempts in each direction, just like a snake turns its head at random around its current position to test variations of the color intensity. for larger bond connectivity, we find a scaling law for the searching time versus the distance to the position of the targets for percolating probability @xmath9. for smaller connectivity, the scaling law is broken and the probability of reaching the goal reduces. under some circumstance  , the hunter may be trapped in dead - end branches of the network which it can hardly get out because of the constraint from the game rules.
t2k ( tokai - to - kamioka )  @xcite is a long - baseline off - axis neutrino oscillation experiment that focuses on measuring @xmath4 and@xmath5 in both @x Math6 and @x math7-modes.   it uses a set of near detectors in order to reduce the large uncertainties on the oscillation parameters that come from the fluxes and interaction models. however, this systematic uncertainty reduction is limited due to intrinsic detector limitations :   differences in most of the target material between nd280 and sk ( pure h@x maths14o ) ; inability to reconstruct low momentum protons at the near detector ; and inability to measure the interaction of the neutrinos with bounded states of 2 protons ( 2p-2h ) and final state interactions ( fsi ) that affect the far detector differently than nd 280 due to the different threshold in proton momentum. here  , we propose to upgrade the nd220 near detectors that will tackle the previously listed issues while keeping the current advantages of the detector.
the existence of trapped or localized eigenmodes in finite waveguides is investigated.   the existence of a trapped mode is related to the smallness of the associated eigenvalue in comparison to the cut - off frequency of the laplace operator in the cross - section of the localization region. using the standard mathematical tools such as domain decomposition, explicit representation of solutions of the helmholtz equation and variational principle  , we show that the presence of trapped modes is dependent on the length of the branch lengths of the waveguide. for a waveguide with infinite resonances,   an eigenmode is trapped if it decays exponentially fast in prominent subregions ( branches ) of the bounded domain, and thus does not propagate when excited at the frequency of its trapped eigenfunction. by reducing the problem to the problem of the propagation of waves in a deformed infinite cylinder, we prove that the localization character of the trapped mode can be explained by the dependence of the location character on the branch length.
the problem of distinguishing the truly quantum properties of a system from those which can be realized in classical systems has received close attention ever since the birth of quantum mechanics.   two key notions that dominate this discourse are nonlocality and nonclassical correlations. here  , we introduce the notion of classical simulation as a new formulation of quantumness by introducing the concept of exceptionality. for the two qubit case, we focus on the existence of spin coherent states ( scs ), also known as atomic coherent states, and present the results for three representative classes of entangled states. to demonstrate the applicability of the term exceptionality, we show that the resolution of identity is not sufficient for a state to defy classical simulation ; instead, violation of bell - type inequalities is necessary.    we also show that quantum correlations in separable states are not always attributable to the weights of the states, but are rather due to the local hidden variable ( lhv ) description of the quantum states.
the dartmouth stellar evolution database ( dsep ) is a set of stellar evolution tracks, isochrones, and computer programs that span a wide range of compositions and photometric systems.   the database includes tracks with masses between 0.1 and 1.8 @xmath2, areochrones with ages ranging from 2 to 15 gyr,  from 2.5 to 0, and initial he content ( y@xmath5 ). in this paper  , we have expanded the set of models to include : ( i ) tracks and isochrone with = + 0.15 ; ( ii ) higher mass tracks and amoebae with ages as low as 250 myr for all compositions ; ( iii ) a wider selection of photometry systems ; and ( iv ) a web interface to three of the computer programs so that visitors can easily generate specific models without downloading the entire database and running the programs locally.    the web interface is available at.
the exchange bias ( eb ) effect is a new paradigm of magnetotransport behavior in a polycrystalline compound, nd@xmath0sr@x Math1coo@xMath2 through the shifts in the magnetoresistance - field ( mr-@x math3 ) curve.   we observe the strong eb effect involved with a fairly largeagranular mr where the value of eb field is found to be much larger than the observation measured through the shift in the magnetic hysteresis loop which is limited to the bilayer or multilayer films only @xcite. also, we observe training effect in the shift of the mr/3 curve which is in accordance with the successful models used to interpret the training effect observed in the geometrical model and a strong time dependence in the resistivity is observed at low temperature which is correlated with the eb effect. finally, we proposed a possible scenario of grain interior magnetic nanostructure to interpret these results.
the drell - yan process @xcite, the production of a lepton pair in hadron - hadron collisions, has played an important role in establishing the parton picture underlying the description of hard interactions in qcd.   recently large resummation effects were recently claimed to be important for the rapidity distribution as measured by the e866/nusea collaboration@xcite. here   we show that this is not the case and that the effect is due to the sharp fall - off of the partonic luminosity at large @xmath0 rather than to the contribution of the _ partonic threshold region, i.e., the region where the center - of - mass energy of the collision approaches the limit of the phase space available for the emission of qcd radiation.
we study the hawking radiation in the rotating black hole embedded in the gdel universe.   we derive the master equation of scalar field in the limit of small gdel parameter @xmath0 and obtain the approximate solution in the low energy and low angular momentum limit by using the matching technique, which has been extensively used in evaluating the absorption probabilities and hawking radiations of various black holes in the five - dimensional minimal supergravity @xcite. for the kerr gdel black hole,   the greybody factor is found to be 1.1 for the rotation parameter@xmath1 of the black hole and 1.2 for the g Del parameter @Xmath0.    the absorption probability and the luminosity of hawking irradiation for the scalar fields are calculated by comparing the results obtained from the matching method with those obtained by the calculation of the mass and angular momentum of the same black hole.
the influence of magnetic impurities on the complex conductivity and surface impedance of a superconductor is investigated by means of tunneling experiments with alloys ( such as pbmn)@xcite and normal metal   supercond conductor bilayers,@xcited by thermal transport in superconducting films.   the results are presented for the experimentally relevant dirty limit ( with respect to the nonmagnetic disorder ) of weak electron scattering off magnetic impurity at low temperature and low frequency over the range of temperature, frequency, and electron scattering rate off the impurity band. using a simple two - fluid model, we show that the effect of localized states on the dissipative conductivity of superconductors containing a single magnetic impure is independent of the energy of the impinging radiation and depends on the density of states within the localized states. under the same conditions, the dissipation of the quantum state is proportional to the number of states in the impure band.
supernovae ia ( sne  ia ) are regarded as the best ( relative ) distance indicators out to redshifts of @xmath4.   the first observational evidence of the accelerated cosmic expansion rate was provided by a series of sn  ial measurements more than a decade ago, and since then a large number of cosmological models have been proposed to account for the acceleration. in this work, we present a model - independent reconstruction of the expansion rate as a function of redshift using a geometrical method that takes into account our expectations towards the underlying cosmology but does not take into account unexpected features that might be present in the data. with only one coefficient for the basis  , we find a suitable reconstruction for the _ hubble parameter, _ h_, using only two coefficients for the expansion coefficients : the expansion constant, @x math5, and the global nuisance parameters, which are taken from the salt2 supernova data set. having such a function, we can compare our results with those of other cosmologies and point to the most likely Cosmological parameters able to reproduce the resulting   hubble _ parameter behaviour.
we develop a model for the steady - state, relativistic, magnetized, rarefaction wave in planar geometry.   the model is a generalization of the one previously proposed by @xcite and @xcite, and it is applied to the problem of the formation of gamma - ray bursts ( grbs ) from a compact central object and accretion disk. at the beginning of the afterglow phase the jet is collimated by either the neutrino annihilation or by magnetic fields, tapping the rotational energy of the central object or disk. when the jet loses its external support when it exits the progenitor star, its motion becomes ballistic and its acceleration is practically halted, this is accompanied by a sideways expansion of the jet, which is driven by a strong raref action wave that accelerates it through stronger collimation of the inner part of the outflow relative to the outer part.the model is tested on a series of case studies, and the results are compared with those obtained by using the ohm s law.
the electron tunneling transport in a rotor - stator molecular system, built of anthracene containing aldehyde side group bound to the central benzene ring, is investigated using the non - equilibrium green s function formalism ( negf ).   the current - voltage ( @xmath1 ) curves in the coherent transport regime, simulating a metal - molecule - metal junction, including also the gating field effects @xcite, are obtained for the two conformer conformers of the proposed molecule, namely, planar and metastable. due to the presence of a flexible dipolar aldehydes side group, this system could be considered as a bistable rotor- and stator - type system, with respect to the three static benzene rings. by applying the negf formalism, we show that the transport properties of such a system are influenced by the position of the molecular charge carrying orbital and the fermi level of the metallic electrodes, and the temperature dependence of the transition probabilities and lifetimes at room temperatures.. the present study shows that the stability and controllability of this system can be controlled by external electric field, even under realistic conditions, reporting also the temperature
the silver blaze problem is a well - known non - perturbative effect of the chemical potential at low temperatures and medium to high densities.   it has been studied previously using the complex langevin approach and mean field techniques @xcite. in this paper   we systematically study the transition at the end of the silver blaze region at zero temperature and attempt to follow the transition line for non - zero temperatures. by using a new flux representation, which avoids the complex action problem at finite @xmath1 and monte carlo simulations at high density, we show that the transition from vanishing to non -zero temperature is not a consequence of the coupling of a charged scalar field with a chemical potential but is due to the formation of a quantum state of matter with a smaller chemical potential than the mass of the state it couples to. as long as the separation between the two states is small enough,   no excitations can be generated and physics must be independent of @x Math1.
the physics of hadrons has been in the spotlight for more than a century.   the discovery of numerous meson or baryon resonances stimulated intense efforts to understand the underlying mechanisms that generate the hadrons. from the very beginning  , the attention was focused on hadrons with properties that look unusual, in contrast to the regularity patterns of the rest of the spectrum. here   we review the history of the search for exotic hadrons, and discuss the current state of the art in the field.
the magnetorotational instability ( mri ) is a mechanism by which the magnetic field can destabilize a hydrodynamically stable flow of a conducting fluid without altering its velocity distribution.   it has been proposed that the mri may account for the fast formation of stars by driving turbulent transport of angular momentum in accretion disks. here   we show that the helical mri can be observed experimentally in cylindrical taylor - couette flow at @xmath5 when the imposed magnetic field is helical rather than purely axial as for the standard mri ( smri ). using a wkb analysis, we find that the hmri is able to destabilize centrifugally stable velocity distributions, but it does not reach up to the astrophysically relevant keplerian rotation profile. however, the stability limit of the real base flow is well within the range of the absolute instability threshold, where it is expected according to ideal t Taylor - couettes flow model.
the cms particle tracking system at the Lawrence Livermore cosmology center ( lhc ) has been used to record the first collisions at the energies of @xmath0  gev and 2.36  tev.   the reconstructed tracks in this data have been studied extensively to commission the tracking detectors and to reconstruct basic physics objects as a demonstration of the performance of the system. in these proceedings  , we describe the results of some of these studies.
the purpose of this study was to observe the formation principles and factors of determination for the connected structures of stock networks using the minimal spanning tree ( mst ) method.   we used the individual stocks traded on the stock market indices of korea, japan, canada, italy, and the uk from january 1992 to december 2006 to construct the stock networks based on the correlation matrix between stocks, using the mst method. in order to create the stock network, we use the kruskal algorithm. according to the results of our observation, stocks which have a large number of links to other stocks in stock networks are more likely to be explained by common factors than those which have only a small number of ties. here  , we describe the data and methods of the test procedures used in this paper. in addition, we present the results obtained according to our established research aims. finally, we summarize the findings and conclusions of the study.
we present an independent test of the gravitational instability paradigm of structure formation, focusing on the clustering of @xmath1 galaxies.   we use the two - point galaxy correlation function ( 2dfgrs ) to measure the higher order moments of the galaxy distribution in a volume limited sample of ~190,000 galaxies with redshifts in the range@xmath11 to @x Math12 using the global mean square root of the universe ( gmrs ). for a gaussian distribution of density fluctuations,   the volume averaged correlation functions, up to sixth order, are identically zero for @x math8 ; the density field is completely described by its variance, @x maths9.. the hierarchical scaling model predicts that the hierarchical amplitudes for the mass distribution are independent of the cosmological density parameter, the Cosmological constant and the cosmic epoch. however, in redshift space the scaling still tends to hold even on small scales where the " fingers - of - god " effect is prominent. as a result  , the results show that the magnitudes of the topology of the cluster distributions are not significantly different from those predicted by the hierarchical scale model.
the transverse acoustic ( ta ) and transverse optic ( to ) vibrational modes of the raman spectrum of the amorphous network   @xcite are highly sensitive to the structural properties of the sample.   for example, the width of the to peak is related to the root - mean - square bond - angle variation @xmath1 ; however, there is no quantitative agreement between the two. in this paper, we re - investigate the relation between @x Math0 and @x math1 by computer simulation.    this simulation is based on a large number of 1000-atom, periodic configurations, with structural properties ( radial distribution function, spread in mean bond angle ) that are in excellent agreement with experiment. using neutron scattering techniques, we also compare the bond polarizibility models proposed by alben and marinov and zotov to experiment. additionally, we present two other methods to obtain structural information from raman spectra : the ta / to intensity ratio @xcite and the location of the t1/t2 peak  @xcitedite.
in the black - scholes framework, the pricing of vanilla options reduces to a numerical integration problem over @xmath0, where @x math1 is the number of underlying assets.   monte carlo integration is known to provide better results when the dimension of the problem increases but for reasonably small dimensional problems, its efficiency is not that clear. besides the usual variance reduction methods, one needs to develop adaptive methods to make them really competitive. in this paper  , we present a new adaptive algorithm for the calculation of sensitivities based on a new splitting criterion and a dimension reduction using a principal components analysis combined with control variates. by combining the two methods,   we show that the new method is more efficient than the old one in low dimensions ( dimension two ) but loses most of its efficiency for larger dimensions ( > 3 dimensions ). moreover, the sensitivity analysis shows that the proposed method is able to compute the delta of the different derivatives using standard deterministic techniques like polynomial interpolation allowed by the high accuracy of our adaptive pricing method.
we present an extended grid of models for the reflection of x - rays from active galactic nuclei ( agn ), galactic black hole candidates ( bhc ) and gamma - ray bursts ( grb ) in hydrostatic equilibium.   the ionization parameter, irradiating spectral index and iron abundance are free parameters. at the same time  , the original code has been expanded to include all abundant species and their important transitions.the resulting grid is used to calculate the reflectance spectra of agn, bhcs and grb x - ray sources. using the fokker - planck equation of cooper, the illuminating radiation is assumed to have a cutoff power - law spectrum that extends to higher photon energies. as the intensity of the irradiation increases, the absorption spectrum is treated separately from the transfer of the diffuse radiation produced via scattering or emission within the gas. by extending the treatment of the diffusible radiation to photon energies above 100 kev, we extend the effect of compton scattering to include the effects of free - electron number density and the energy of the scattered radiation field. here   we show that the results are in good agreement with those of ross, fabian
we investigate the formation of the first baryonic objects in a cosmological model in which dark matter is warm, rather than cold.   we find that the abundance of primordial gas clouds and of their host halos with dark masses @xmath22 in a cold dark matter ( cdm ) model is significantly smaller than in a warm dark matter model ( wdm ), and that the observed abundance of substructure in distant galaxies is much smaller in the wdm model than in the cdm model.    we conclude that the two models are incompatible with each other in terms of early structure formation.
the community structure of complex networks is still rather elusive.   the definition of community is controversial, and should be adapted to the particular class of systems / problems one considers. in this paper   we focus on another major problem affecting clustering techniques : most of them, in fact, do not deliver a unique answer. in the presence of several outputs of a given method,   is there a partition more representative of the actual communities structure of the system?   if this were the case, one would need a criterion to sort out a specific partition and discard all others. here  , we propose a new greedy strategy to solve this problem, which uses the consensus matrix as an input for the graph clustering technique adopted, leading to a new set of partitions, which generate a new consensus matrix, etc. until a unique partition is finally reached, which can not be altered by further iterations.we show that the proposed algorithm is able to detect clusters in real networks with high internal edge density and a high degree of modularity, even when the clusters are loosely connected to each other.
we compute the effects of pion loops on the amplitude of the decay of a neutral pion into two photons, using a gauged nonlinear sigma model which properly incorporates all anomalies by inclusion of the wess - zumino - witten ( wzw ) term in the effective lagrangian for @xmath3.   we find that the pion decay amplitude is directly related to the coefficient of the axial anomaly, and that the effect of temperature on this relationship is more involved than previously thought.
question answering ( qa ) aims to automatically understand natural language questions and to respond with actual answers.   the state - of - the - art qa systems usually work relatively well for factoid, list and definition questions, but they might not necessarily work well for real world questions, where more comprehensive answers are required. in this paper, we propose a novel word - alignment - based method to solve the frequently asked questions ( faq ) based qa tasks.. the characteristics of our method include : ( 1 ) a neural network model for calculating question similarity with word alignment features. for an input question and a candidate question, the similarities of each word pairs ( between the two questions ) are calculated first, and then the best word alignment for the two Questions is computed.    we extract a vector of dense features from the word alignment, then import the feature vector into a neural networks and calculate the question similarity in the network s output layer.,2 ) a bootstrap - based feature extraction method..,3 ) a learning - to - rank algorithm for training. ’ experimental results, conducted on faq archives from three languages, demonstrate that our method is very effective. also, we also evaluate
3c  58 is a pulsar wind nebula that has been suggested to be plausibly associated with the 831 years - old supernova sn 1181.   we present an analysis of the nebula evolution using a detailed radiative, time - dependent, leptonic code. in the model,   the pulsar winds are modeled using a diffusion - loss equation, which includes the energy losses due to synchrotron, ( klein - nishina ) inverse compton, bremsstrahlung, and adiabatic expansion as well as the injection of particles per unit energy and unit volume in a certain time. at the high - energy end of the spectrum  , we find that the fluxes of electrons and photons are very fast, e.g., ~1.5  kcal / mol / mol for the ionic component of the jet, and the rate of expansion is about 1.5 times faster than that of the primary particles. however, the escape time from the jet is much slower than expected, and this is explained by the fact that the spin - down of the pulsa is assumed to be independent of the radiation from the supernova.
short - time universal scaling behavior of non - equilibrium critical dynamics starting from a high temperature state was systematically explored with renormalization group methods @xcite.   the results confirm that there exists a rather general dynamic scaling form in critical dynamic systems already in the short - time regime of dynamic evolution. for the simple ising and potts models with only nearest neighbor interactions,   sometimes the scaling form is negligible small ( e.g., one monte carlo time step or two ). compared with typical macroscopic time scales characterized by @xmath4 or@xmath5 around the critical point, the low - time dynamic scaling is indeed very small.    the physical origin of the short-time dynamic scale is the divergent correlation time near a critical point which induces a memory effect, and the memory effect can be described by a scaling form.
the cosmic baryon budget at low and high redshift indicates that a large fraction of baryons in the local universe have so far escaped detection ( e.g., @xcite ).   we report the first detection of an ly@xmath0 absorption line along the sightline towards pks  2155 - 304 at @xmath13 plausibly associated with an  intervening _, modestly overdense region in the intergalactic magnetic field ( igm ). using the _ chandra _ letg - acis ( advanced ccd imaging spectrometer ), we show that the gas that gives rise to this resonance line has the typical properties of the warm - hot intergalaxy medium, or whim, indicating the detection of a significant fraction of the " missing barytons ".
dynamic mode decomposition ( dmd ) is a new modal decomposition method that combines the advantages of power spectral analysis in time and principal components analysis in space.   we have applied dmd to sub - dural electrode array recordings from human subjects in two different contexts : first, we validated the dmd approach to derive sensorimotor maps based on a simple movement task ; next, we leveraged dmd in combination with machine learning techniques to detect and characterize spindle networks present during sleep ; a method to automatically extract these stereotyped sleep spindle network networks had not been described previously in the literature. using this approach, we show that sleep spindles tended to occur coincidentally in different groups of electrodes at different times.. these patterns may reflect some underlying anatomical or functional connectivity in the brain, and studying relatively local spindle Networks may be a novel way to understand the organization of the brain.
we present a method that exploits correlation between spatial and semantic information in the convolutional layers and localization of an object of interest within an image.   the method is based on deep convolved neural networks ( cnns ) which are trained using image - level labels to predict the presence of objects of interest in new test images. for each class of interest,   we propose localization candidates ( or bounding boxes ) which maximize classification scores for the corresponding classes. as we progress to finer localizations, we explore smaller and smaller regions of interest till the classifier is no longer able to discriminate amongst the classes of interest. to approximate the search for optimal localization candidates, we adopt a beam search strategy where the number of candidate bounding Boxes is restricted as we proceed to fine localizations.    we outperform the state - of - the - art in localization accuracy by a significant margin of up to 8 map on two standard data - sets with complex scenes, pascal voc 2012 @xcite and the much larger ms coco.
the relativistic heavy ion collider ( rhic ) at brookhaven national laboratory ( bnl ) has been providing heavy ion collisions in the attempt to create the quark - gluon plasma ( qgp ) within the laboratory.   some of the most striking data from the first few years at rhic were results from the apparent interaction of hard scattered partons in the medium produced by the collisions with high-@xmath4 hadrons. these data have been interpreted as the loss of energy of a colored parton traversing a colored medium, analogous to energy loss in qed. however, many of the details underlying qcd energy loss are not well understood. to overcome such biases, it is necessary to move beyond multi - particle correlations and measure jets directly inheavy ion collisions.. this note highlights the current status of jet reconstruction and energy loss measurements expected to be made with the atlas detector at the large hadron collider.
we analyze the model of a positive stream of pulses in which the measured data is modeled as the convolution of a sparse positive signal on the sphere, which represents the unknown orientations, with a known point spread function that acts as a low - pass filter @xcite.   we estimate the set of delays and the positive amplitudes from the measurement data using the one - dimensional model given by @xmath13:=\sum_{m}c_{m},\boldsymbol{\delta}\left,\quad c_{m}.>0,\label{eq : x}\ ] where @x Math13 is the one-dimensional kronecker delta function.    we also analyze in detail the models of two - dimensional positive streams of pulses given by@xmath19 & = & \left(\mathbf{g_{2}}\ast\left(\frac{k}{\sigma n}\right)\right)\left/\begin{cases } 1, & k=0,\\ 0 & k\neq 0.
quantum walks provide a quantum extension of the ubiquitous classical random walks and have important applications in a broad range of fields including solid - state physics, polymer chemistry, biology, astronomy, mathematics and computer science.   the continuous - time version of quantum walks ( continuous - times quantum walks, ctqws ) has been extensively studied as effective model of energy transport in molecular systems such as chromophoric light - harvesting complexes @xcite. here   we study the survival probability of a ctquw moving on an erds - rny ( er ) graph in the presence of a fixed concentration of traps randomly placed.. the number of traps as well as the substrate connectivity encoded by the average number of neighbors per node are properly tuned in order to account for their role in affecting the trapping performance.    our results highlight that at long times and when the trap concentration is small, for large size and intermediate degrees of dilution, both quantal and classical survival probabilities typically decay exponentially with time. however, while the classical decay rate increases monotonically with the trap concentrations of @xmath2, the quantal decay rate displays a subtler dependence. indeed, given a fixed number of randomly arranged traps
ngc  5548 is one of the brightest seyfert 1 galaxies with optical / uv / x@xmath0 continuum consisting of three characteristic components : the big blue bump, the soft - excess, and the hard x - ray thermal comptonization continuum with the reflection hump.   these components are known to be highly variable, but there have been no observing campaigns covering all of them simultaneously. here   we re - analyze the variability correlations in a simultaneous sub - set of available data from the _   iue_/_ginga _ campaign using a continuum model and apply it to re - analysis the average spectra from non - simultaneous observations.    we find that thesoft - excess component contributes significantly up to an energy @xmath12 kev, which is marginally observed in the _ ginga _ data. as was shown by fiore, matt, and nicastro ( 1997 ), this component can not be simply explained by atomic processes. on the other hand,   extrapolation of the _ rosat _ soft x -ray power - law points exactly to the uv component, suggesting a comptization origin.. however, comptonizing the disk
@xcite + resonance - enhanced multi - photon ionization ( rempi ) is a sensitive probe of photoionization dynamics in the gas phase as it originates from the quantum interference of outgoing partial waves when the photoelectron is scattered off the chiral molecular potential.   the influence of the electronic character of the intermediate on the dependence of photoelectronic circular dichroism ( pecd ) on wavelength has been investigated before. in this contribution, we extend previous studies on wavelength dependence with a step size smaller than the bandwidth of the femtosecond laser and observe distinct 2 + 1 rempi channels via the b- and c - band transitions, which are believed to correspond to 3s @xmath0 n and 3p @x math0 n excitation, respectively. by employing rempi schemes, ionization via different electronic intermediates   can be investigated by tuning the wavelength of the laser. using a continuous wavelength scan covering several excited states, we show that the magnitude of pecd increases with the step size of the step larger than 0.5 ev for the b - band transition and decreases with increasing step size for the c -band transition. at the same time, the asymmetry in the photo
the detection of a nearby supernova is a high priority in both neutrino astrophysics and gamma - ray astrophysics.   the difficulty is that nearby supernovae are rare. while gamma rays are of course easier to detect, type - ia supernova are more rare, and the number of emitted particles per supernova has been estimated to be less than 1/100,000. here   i discuss the prospects for detecting the type - ii supernova neutrinos from sn 1987a  @xcite.
the maser emission from hydroxyl ( oh ), water ( h@xmath0o ) and silicon monoxide ( sio ) molecules in the outflowing stellar winds of 86 post - agb stars has been studied using the parkes radio telescope.   the results show that the more massive sources in the sample, designated li ( sevenster 2002b ), are likely precursors of bipolar planetary nebulae ( pn ) while the less massive sources ( ri ) evolve into elliptical or spherical pn. analysis of the maser properties of the li and ri objects, together with a study of the early and late post-agb objects, will give insights into the origins of the different morphologies in pn.see research article http://www.biomedcentral.com/1471-7009/7/8/10 for details of the experiment.
quantum chromodynamics ( qcd ) allows for various types of hadrons.   first, the meson and baryon spectra computed from either constituent models or lattice simulations @xcite in @xmath3-dimensions were found to be in very good agreement with the experimental spectra@xcite. beside these conventional hadrons, qcd does not forbid the existence of other exotic resonances like glueballs, hybrid mesons, tetra- and penta - quarks, etc. because of the obvious connection with experimental data, glueball properties have mostly been studied within a yang - mills gauge theory with two spatial dimensions, which exhibits peculiar features, that will be detailed below.
we employ a real - space self - consistent field theory to study the micelle shape in a confined blend of diblock copolymer / homopolymer blends.   the confinement - induced micelle formation in the thin film is investigated by using monte carlo simulations of the bond fluctuation model in two - dimensional ( 2d ) and three - dimensional(3d ) confined blends of symmetric diblocks copolymers and homopolymers, and the influence of the confinement parameters on the micelles formation is investigated. for the first time, we investigate the effect of the surface separation and micelle concentration on the morphologies of the micelles under planar and one - dimensional confinement. as the confinement dimension increases, the size of the mouselles decreases, but the micells are not affected by the change in the surface interaction parameters. at the same time, the miceles form different morphologies such as perforated lamellae, bilayer sheets, cylinders or spheres depending on the confinement parameter. when the confinement is weakly weakly constrained, the micella forms a corona - like structure with a diameter of about 1.5  nm, whereas when the
we present a statistical analysis of the fisher information based on delay times between detector clicks in photon counting experiments.   we exploit a specific property of the quantum trajectories associated with fluorescence records from two - level emitters : the signal is a discrete set of detection times, and after each detection event the system populates the same state and recommences the same evolution. since this distribution can be determined analytically, our method permits analytic calculations and interpretation of the results in different limits along with a straightforward incorporation of finite detector efficiency in the analysis.
lateral organic spin valves ( osvs ) hold the promise of integrating non - volatile switching into organic field effect transistors ( ofets ).   however, they are much more difficult to fabricate than vertical spin valves due to the need for highly sophisticated patterning of the organic semiconductor ( osc ) and the small gap between the two electrodes which is filled with the osc. in this work   we present a novel fabrication process for lateral spin valves with channel lengths of less than @xmath0 and contamination free interfaces using a combination of optical lithography, lift - off, and shadow evaporation under different angles.    the process yields uncontaminated interfaces, a small gap for the oc and contacts with a sizeable difference in coercive field, and a large area shadow mask with rectangular windows that can be used to achieve well separated and uniform devices without the use of a mechanically fabricated mask.
entanglement is one of the most interesting aspects of quantum mechanics due to the fact that there is no classical analog.   it is generally difficult to study entanglement because the calculations become challenging as the dimension of the hilbert space increases. in this paper,   the restriction to states which are symmetric under permutation of party labels greatly reduces the number of parameters and simplifies the calculation of 3 qubit local unitary invariants.
we present the mid - ir spectra of the prototypical seyfert 2 galaxy ngc 1068 ( @xcite ), which is part of the active galaxy proposal camactiv ( p.i.   mirabel ), and show that the emission between 5 and 16@xmath0 m is clearly dominated by the agn, but faint extended starburst emission is also observed along the northeast - southwest axis. due to the proximity of this galaxy ( 14.4mpc, 1@x Math5=72pc ) to the nucleus, we can disentangle the ag n from the star formation regions found at 20@x math5 from the nucleus. in order to point out, in a more general way, different methods for distinguishing an agn within a dominant starburst environment, we have used the circular variable filter ( cvf ) for mapping the central region of ngc1068 continuously from 5 to 16@X maths0 m with a spectral resolution of @xmath740 using the isocam camera on board the infrared space observatory ( iso, @xcitescam).the most striking difference is the absence of the family of uibs at 6.2,
we calculate dc josephson current - phase relation ( c@xmath6r ) of a long spinless contact between two gapless superconducting leads supported by chiral majorana modes in a chiral fabry - p'erot interferometer implemented on a surface of 3d ti partially gapped by superconductors and magnetic islands.   the system under consideration is a hybrid structure where the normal conducting region consists of two separated chiral dirac channels supported by magnetic domain walls, which are effectively gapless due to chiral mainana modes at their edges. for the first model,   four chiral y - junctions are used as direct charged - to - neutral fermion converters while for the second one two tunnel contacts are formed by thin layers of magnetic material where majorana and normal Dirac channels are hybridized. both models are based on the assumption that the length of the n - region, formed by two counter propagating 1d dirac modes, is larger than coherence length of induced superconductivity. in the present work   we show that the critical current has a fractional @xmath11-periodicity rather than the conventional @x Math
we investigate the effect of dephasing in molecular transport properties of a single benzene molecule attached to electrodes via thiol groups using bttiker probe model and density functional theory ( dft ).   we find that the electron - phonon interaction between the electrons in the molecule and the fictitious floating voltage probes in the coherent system is responsible for the dephased transport properties, which can be studied experimentally by means of inelastic tunneling spectroscopy. with the help of quantum mechanical treatment  , we show that the eigenenergies of the phonons in the molecular transport junctions can be quantified by measuring the vibrational spectrum of molecular vibrational peaks in the second order derivative of a current - voltage characteristic obtained by scanning tunneling microscopy. as a result,   the experimental results are in good agreement with the theoretical results.
violation of charge - parity ( @xmath0 ) symmetry beyond the standard model ( sm ) has yet to be observed but we suspect that it must be there in order to explain the baryon asymmetry of the universe.   we consider triple - product correlations in top - quark pair production at the lhc, induced by new @x math0 violating interactions in a scalar sector extended with a color - octet electroweak - doublet as described in ref. , where we present a set of parameters for which the resonance is visible over the sm background and the resulting @x Math0 asymmetry can be as large as a few percent. within this framework  , we find that relatively large raw asymmetries are possible, as larger as @x maths12.5%. however, these results are diluted by the existence of the sm top -Quark pairs and their observation is contingent on the resonance itself being observable.
the evolution of the fundamental plane and the m@xmath4-@x Math5 scaling relation is reviewed.   the evolution of these relations is also briefly discussed, as well as the relationship between stellar velocity dispersion and total mass as measured by strong gravitational lensing.
the existence of self - organized critical dynamics in complex systems has traditionally been demonstrated through numerical simulation of certain classes of cellular automata referred to as sandpile models @xcite.   non - linear, spatio - temporal dynamics is always essential for the emergence of critical dynamics, but the details of this dynamics for a specific natural system are often poorly understood and/or not accessible to observation. in this letter   we report some results which provide a partial answer to such a question. using a benchmark case against which our results are tested, is a numerical study of the bak - tang - wiesenfeld ( btw ) Sandpile @xcites.. we find that the probability density function for the toppling activity is a stretched exponential or close to the bramwell - holdsworth - pinton distribution@xcite, depending on whether the sandpleis is so slowly driven that avalanches are well separated, or it is driven so hard that several avalanches run simultaneously. by redefining the meaning of an avalanche to be the activity burst between successive times for which the activity rises above a positive threshold, we can re - scale the dynamical variables which allow a natural passage to the therm
the pionic decay of @xmath0 hypernuclei in a nuclear medium is studied by means of a continuum shell model ( csm ), which is based on the woods - saxon ( ws ) shell model of the decay.   the model is improved by using more realistic potentials for each one of the nuclei by fitting the parameters of a ws well, with spin - orbit forces, to the ground state and also to some of the discrete final state energies of the involved nuclei involved in the decay, and by using a continuumshell model to describe the positive energy tail of the mesonic decay width. as a result  , the new model is able to reproduce the experimental measurements of the @x Math1-@xmath3 decay of ~2.5  kcal / mol at kek, and it provides an upper bound for the corresponding @x math6 and ~4 decay channels.
sn 1995n ( also known as arp 261 ) is a peculiar type ii supernova in the type iin category.   it was discovered by pollas ( 1995 ) on 5 may 1995 at a distance of 24 mpc from the host galaxy, and its optical spectra show it to be a peculiar object with h@xmath2 emission and narrow lines of he  i, he  ii, , ,,-+, -, , fe  ii,/fe  iii, /fwhm,  @xmath6, and very narrow emission lines whose intensity ratios indicate high gas densities. here   we report the results of baseline interferometry ( vlbi ) radio and x - ray observations of sn 1995n in mcg02 - 38 - 017, which show that the supernova has a rapid expansion velocity of up to about 1.5 times that of the Milky Way, and that it is running into dense circumstellar cl
the quasicontinuum  ( qc ) method is a reduced - order modelling method with a concurrent multiscale character that resolves the underlying lattice only in small regions of interest, whereas it coarsens it elsewhere.   this results in a considerable reduction of the number of degrees of freedom  ( dofs ), internal variables, and effort to construct the governing equations. here  , we present a refinement of the variational qc method that allows for the removal of nodes in the wake of the crack tip to increase the efficiency of the approach.. the proposed approach is based on the partition of unity  ( pu ) concept, which enables the space of interpolation functions to be enriched to include " jumps " in kinematic as well as in internal variables. by enrichment,   such an enrichment provides an accurate and efficient framework to model cracks in damageable lattices at the micro- or meso - scale using the extended qc methodology.
the problem of scattering from a point defect in a hard - walled, multimode quantum waveguide is the subject of experimental and theoretical inquiry in both condensed matter and atomic physics. in this paper  , we revisit the problem from an unconventional point of view, reducing it to the scattering of a single effective wavefunction off an array of images.   our approach enables us to easily understand complex transport phenomena which have already been observed ( such as conductance dips ), as well as predict other new ones.
zipf s law is one of the most common power laws found in nature and society.   it was popularized by the linguist george kingsley zipf, who observed that it accounts for the frequency of words within written texts. here   we adapt and enrich the general framework proposed in @xcite to the communicative context. as a result  , we show that zipf s hypothesis can be interpreted in such a way that the system can be studied within the frameworks proposed in@xcite. moreover, the parameters that were arbitrary in the general mathematical framework mentioned above can now be naturally interpreted in the Communicative framework as the key pieces of the mathematical statement of zipfs hypothesis.
abstractthe _ kepler _ satellite @xcite has identified more than 200 known planets with measured masses and radii, and is currently searching for more than 3000 planet candidates.   the mass and radius of these planets have been measured by radial velocity and transit observations, respectively, and are in good agreement with those of the solar system planets ( including jupiter and saturn ). however, the interior structure of the most massive planets ( " gas giants " ) is still poorly understood.. here we review what is known about the structure of such planets, and consider how our knowledge of the structure might improve over the next decade.
hii galaxies are local, dwarf starburst systems ( e.g., 1/50 @xmath0 z / z@xmath1 = 1/3 ), which show low metallicity.   wolf - rayet ( wr ) signatures, indicating the presence of wr stars, have been found in the spectra of some hii galaxies, but they are not expected in metal - poor environments @xcite. using integral field spectroscopy ( ifs )  , we have observed 15 hii galaxy with wr features using the optical ifus : pmas at the 3.5 m telescope at caha and integral at the 4.2 m wht in orm. here   we summarize here some recent results on mrk178, one of the most metal -poor nearby wr galaxies, which shows that the origin of high - ionization nebular lines, apparently more frequent in high - z galaxies, is still an open question. from the sdss spectra, we find a too high ew(wr bump ) value for mr k178, which is the most deviant point among the metal -Poor wr galaxies ; this curious behaviour is caused by aperture
we investigate the quantum dynamics of two nonlinear anharmonic oscillators interacting with a linear oscillator.   we show that the nonlinearity of the oscillator results in a time - dependent entanglement between the two oscillators, which is much more pronounced for certain initial states. when dissipation is included, the effect of nonlinearities strongly governs the steady state evolution of the indirectly coupled nonlinear oscillators. as a second example  , we investigate the unitary evolution of a cavity mode acting as an an Harmonic oscillator and a movable mirror acting as a vibrating cavity mode. under the joint action of radiation pressure coupling and intrinsic nonlinearness   the vibrating mirror will also exhibit non - classical dynamics.
the temperature and surface gravity of the da white dwarf star, where nuclear burning has long since ceased, can be determined from the lyman  @xmath0 line profile.   however, the measurement of these features is compromised when the white dwarf is not visible in the stellar spectrum. to address this problem, we have developed a new method for the determination of the temperature and gravity of a large sample of da white dwarfs using the _ orfeus_spectrometer and the _ iue   hst   spectrometer. by combining the measurements of the two spectroscopic techniques, which are based on the analysis of multiple lyman lines, we show that the maximum effective temperature of the most luminous star in the binary system v471 tauri ( k2 + 1 ) can be obtained from the full lyman series with a precision of 0.5  kj / cm2 for the first time. while the results are consistent with the results obtained using the balmer line technique, they are significantly lower than those obtained with the  balmer lines for the same star in several other systems. as a result, the new method is able to provide an unambiguous measurement of both the
synchronization is a phenomenon observed in many different contexts, ranging from epidemics spreading @xcite to neuro - sciences.   the analysis of simple models pursued in the last two decades has clarified several aspects of synchronization. among them   are the mechanisms of mutual synchronization between two replicas of a spatially extended system coupled either via local interaction or via spatio - temporal noise. in both cases, when the amplitude of the coupling ( noise ) overcomes a certain threshold, synchronization is observed : after a transient, the two systems follow the same chaotic ( stochastic ) orbit. in this paper   we present a new model of synchronization in an extended system represented by a coupled map lattice with power - law interactions which reduces to globally coupled maps ( gcm s ) and to standard coupledmap lattices ( cml s ) with nearest neighbor coupling in the limit. for model (  @xmath10 )   it is shown that the transition from a desynchronized state to a completely synchronized one along a chaotic orbit can be predicted within a linear analysis as the value of@xmath5 for which the transverse lyapunov exponent ( tle ),
we present a new and accurate fortran code, the bi - spectra and non - gaussianity operator ( bingo ), to numerically evaluate the scalar bi - spectrum and the non - Gaussianity parameter  @xmath0 for single field inflationary models involving the canonical scalar field.   the code is based on the recently published data on the anisotropies in the cosmic microwave background ( cmb ) data and can be used to examine the power of the dimensionless non -gaussianity factor @x math0 to discriminate between different inflationary model classes that admit deviations from slow roll and generate similar features in the Scalar Bi - spectrum.
spectral graph theory examines relationships between the structure of a graph and the eigenvalues ( or spectrum ) of a matrix associated with that graph.   there are graphs which have the same spectrum for a certain matrix but different structure  such graphs are called cospectral with respect to that matrix. in this article   we will review the history of spectral graph theory and discuss some of the matrices which have been studied in detail in the literature which are known to give different information than the common matrices.
we investigate the steady - state solution of bose - einstein condensates ( becs ) in an one - dimensional periodic optical lattice when both the two - body and three - body interactions are taken into account. by using the mean - field approximation and linear stability theorem,   one interesting result is found that the tuning - fork bifurcation of steady - states relative population appears when the system parameters are changed to certain critical values.   the existence of three-body interaction not only transforms the b ifurcation point of the system but also affects greatly on the macroscopic quantum self - trapping behaviors of the systems associated with the critically stable steady -State solutions. additionally, we also study the effects of the initial conditions, three -Body interaction and the energy bias on the self - trapped behavior of a bec in optical lattices. by applying the periodic modulation on the energy biases, we show that the relative population oscillation can undergo a process from order to chaos, via a series of period - doubling bIfurcations.
cardinal interpolation is the interpolation of data given at the integer lattice from a radial basis function.   it is a well - known property of radial basis functions that they take value 1 at the origin and 0 at all other integers. in this paper  , we explore the possibility of using fundamental functions as interpolants for cardinal interpolations of bandlimited functions in any dimension via interpolants of the form discussed above. to illustrate this, we consider the general multiquadrics, @xmath0, which have thus far only been considered for certain exponents @x Math24.. we find that the decay rates of the univariate fundamental functions associated with these general multquadrics are much faster than those of the general multi - integer multiquads, and that the results are consistent with the one - dimensional whittaker  kotelnikov  shannon sampling theorem.
the isovector giant dipole resonance ( ivgdr ) is the only giant resonance experimentally studied extensively at finite temperature ( t ) and angular momentum ( j ).   the width of the resonance corresponds to the damping of the collective vibration due to the viscosity of the neutron and proton fluids @xcite. in this study, we have investigated the apparent gdr widths in hot nuclei at t@xmath133.5 mev and j=15 using the thermal shape fluctuation model ( tsfm ) for the decay of the gdr from the excited nuclei. as the rotational frequency becomes larger, the nucleus undergoes an oblate flattening due to centrifugal effects and the equilibrium deformation ( @xmath14@x Math15 ) is observed. on the other hand, the nuclear symmetry energy decreases with increasing temperature and the diameter of the nucleus increases with increasing angular momentum while the apparent wideening of the resonances increases with both temperature and angular velocity. by taking into account the effect of the spreading effect, we show that the average nuclear deformation and the apparent widening of the raman resonance do not follow a linear relationship when the actual t - dependence
quantum correlations between two ultra - cold atoms trapped in a harmonic trap are controlled by the scattering length of the trapping potential.   the nature of quantum entanglement arising from s - wave scattering has not been fully explored, and it may have effects on the fidelity of quantum gates based upon collisional mechanisms. in this paper   we analyze the quantum entanlement of the low energy eigenstates defined by the regularized pseudo - potential and the harmonic trap under the shape independent approximation. by performing the schmidt decomposition of low energy Eigenfunctions, we show that quantum entenlement is manifested as pairing of atoms in a set of orthogonal mode functions in three - dimensional space. using the angular momenta as good quantum numbers to characterize the Schmidt mode functions, we present numerical results that quantitatively quantify the degree of entanglements as a function of the scattering lengths @xmath0. for a given inter - atomic potential,   such a strong coupling regime corresponds to the unitarity limit in degenerate quantum gases.
galactic outflows can regulate star formation by heating cool gas @xcite.   they can also enrich both intergalactic medium and galactic disks with the maximum starburst @xxcite, which may explain the apparent discrepancy between the theoretical prediction of the dark matter halo mass function and the measured stellar mass function for galaxies in the successful @xmath12cdm scenario. in this letter  , we probe kinematic signatures of molecular outflows in a sample of 27 ultra - luminous infrared galaxies ( ulirgs ) recently studied by@xcite using a stacking analysis to look for faint and broad high velocity line wings in the @x Math0co line profile. in order to inspect outflow driving mechanisms,   our ulirg sample is partitioned into two groups based on optical emission line diagnostics : starburst dominated galaxies and galaxies with large agn contributions. with the reduced noise in the stacked composite spectrum, we also measure the average brightness of other weaker molecular lines as an independent measurement of molecular gas properties, that have been detected only in the nearest nearest luminous galaxies. from the results of our analysis, we conclude that the galaxy with the largest agn contribution is the most likely to have
the boson peak anomaly in the vibrational density of states ( dos ) of glasses is a well - documented feature of the phonon spectrum of defect - free crystals.   it has been attributed to the lowest van hove singularity in the spectrum of the reference crystalline system, which is shifted to lower frequencies by disorder - induced level - repulsion effects. here   we present numerical results for both model glasses and defective crystals with randomly - cut bonds, and a new conceptual framework to explain the bosonpeak based on a unifying local symmetry principle. using this framework, we show that the low-@xmath8 peak in the reduced dos of the silica glass and the @xmath9-quartz crystal with matched density, having the same average atomic connectivity, as well as the same density and interatomic interaction, display the sameboson peak in spite of having very different values of bond - orientational order. within our framework,   the local breaking of inversion symmetry appears to be the only microscopic structural signature that correlates with the emergence of the Boson peak at sufficiently small wave - vector, without leading to contradictions or paradoxes.
we report the results of a blind search for high - redshift co emission lines in a dusty, star - forming submm galaxy ( smg ) using the multi - band heterodyne receiver, emir, at the iram 30 m telescope.   the 3-mm ( e090 ) set - up of emir provides 8ghz of instantaneous, dual - polarization bandwidth and is capable of covering the entire accessible frequency range, @xmath5ghz, with five tunings : 0@xmath6@x Math7@x math60.4 for co(10 ) and 1.0@x maths6@Xmath7@ xmath68.7 for the co lines between ( @xMath8) and ( 76 ).    we find that the redshift of the smg, smmj14009 + 0252, can be determined by comparing the spectroscopic spectrum of the source with the data from the emir observations. erytheoretical calculations show that the observed redshift is ~1.2  kcal / mol ( kj / mol ), which is within the range of the known redshift distributions of the existing literature. to demonstrate the
the vortex penetration process of a type - ii superconductor is usually retarded during the penetration process because the vortices are subjected to surface attractive force, bulk pinning forces, internal field repulsive force and damping force.   the experimental observations have shown that the internal magnetic field of a high-@xmath2 supercond conductor is strongly time dependent after a magnetic field ( below irreversible field ) is applied to the supercondonductor. for the purpose of application,   it is important to construct a mathematical model which includes the effects of the bulk Pinning and internal Field Repulsive force, and can predict the time scale of the vortex penetration processes. in this article   i theoretically show that the vortex integration process is time dependent because of the surface attractive Force, bulkpinning force and internal fieldrepulsive force. using the arrenhius relation  , i derive a time dependent equation for the internal field in a Vortex penetration process.
the interplay of the bragg gratings ( bgs ) with the nonlinearity of the fiber material gives rise to gap solitons, which can be used to create complex superstructures on top of regular gratings.   we have studied the effect of a local finite - width defect on the propagation of light in a nonlinear bg with a spatially inhomogeneous bragg reflectivity, i.e., one with a narrow embedded layer carrying large reflectivity of the opposite sign, and a periodic modulation of the local refractive index and local brag reflectivity. using the coupled - mode equations for the amplitudes of the right- and left - traveling waves in the apodized bg, we show that the observed behavior of the light propagation in the bg obeys the system of coupled - modes equations for amplitudes and self - phase - modulation coefficients of the waveguides, taking into regard a phase shift between the incident and reflected waves. by means of the perturbation theory, we have developed a new model of the interaction of moving bg soliteons with weak local defects, which is consistent with the results obtained experimentally from the theoretical model.
this paper studies orthogonal frequency - division multiple access ( ofdma ) based cellular systems with universal frequency reuse, in which adjacent cells share the same frequency band for simultaneous transmission to improve the spectrum efficiency.   however, for such systems, the inter - cell interference ( ici ) control becomes crucial, which has recently drawn significant attention. in this paper, we study a new approach to design cooperative resource allocation across different cells by exploiting frequency - domain precoding over parallel subcarriers ( scs ), by means of interference alignment ( ia ). from the numerical experiments under a symmetric channel setup, we find that the ia - based resource allocation scheme demonstrates its advantages over the traditional scheme without ia only when the cross - cell link has a comparable strength as the direct link, and the receiver signal - to - noise ( snr ) is sufficiently large. motivated by this observation,   a hybrid scheme is proposed for practical cellular system with heterogenous channel conditions. in both the hybrid scheme and existing resource allocation schemes, all the scs are treated as separate dimensions for user selection and power allocation ; however, the network - level signal cooperation at the base stations ( bss ) is modeled as
we have recently proposed an orthonormal basis of vector slepian harmonics ( vslhs ) which are naturally suitable for approximating the illumination in a high numerical aperture ( na ) system.   the main advantage is that a subset exhibits excellent directionality, i.e. its angular energy distribution is confined to the solid angle of illumination. in this paper  , we demonstrate the applicability of these novel vector bases for general inverse problems in high na focusing using three examples : the optical needle, tube and bubble.
the smeagol code@xcite was the first to describe spin - dependent and finite - voltage transport properties of systems with inhomogeneous magnetic moments and in the presence of spin - orbit scattering.   it is now almost 10 years since the release of its first version and during this period, we have developed a new code with increased speed, versatility and functionality, which is particularly suited to the modeling of larger - scale nanostructures, interacting with their environments.the new code is called gollum and will be freely available from _ http://www.physics.lancs.ac.uk/gollum_ within the coming weeks.
in our previous paper, @xcite ( hereafter k09 ), we showed that an exomoon should induce not only a transit time variation ( ttv ) effect but also a transit duration variation ( tdv ) effect on the host planet.   the two effects were predicted to exhibit a @xmath5 phase difference which could be used as the hallmark signature of anExomoon. in this paper  , we extend the theoretical framework to include non - coplanarity and predict that the tdv effect is due to two primary constituents : i ) a velocity ( v ) component and ii ) a transit impact parameter ( tip ) component. since transit duration is a strong function of impact parameter, it is reasonable to expect constructive interference with the v - component in the case of a prograde exom moon orbit and destructively for a retrograde orbit. as a result, the expected tdv signal from an exo - moon is even more detectable. furthermore, we predict this asymmetry could allow for a determination of the satellite s sense of orbital motion.
1es 1101232 ( z=0.186 ) is an extreme case of high - peaked bl lacs ( hbl ) in which the synchrotron component peaks in the x - ray band ( @xmath0 1 kev ).   we have observed 1es1101232 on two occasions, on 4 jan 97 and 19 jun 98. a single power law fit with galactic absorption at low energy   is rejected for both observations, while a broken power law yields an acceptable@xmath1.    we therefore fit the two datasets together, by using an appropriate model ; the best fit of a brokenPowerLaw model, in which only the high energy index @x Math4 is untied between the two observations, is acceptable. 	 the fluxes are consistent with those obtained by the separate fits. only the intensity above 2 kev changed ( of @x math5 ) between the second observations., even if the flux variation is small, this result might bear an impact on spectral variability models in bllacs.
extreme ultraviolet ( euv ) observations provide the most important source of information on the low solar corona.   the atmospheric imaging assembly ( aia ) aboard the solar dynamics observatory ( sdo ) provides very fine temporal and spatial resolution of the sun at multiple wavelengths, and is having a large impact on the field. despite the development of automated detection tools for euv observations, most scientific works begin from visual inspection of images. in particular, the volume of data provided by aia / sdo is so high that low - resolution images are often used as a starting point to find features of interest. however, image processing is therefore an important step in analysing the data. here   we present a new method for revealing features in euv images using the recently - developed noise adaptive fuzzy equalization ( nafe ) method @xcite. the method uses a fuzzy membership function of a gaussian - weighted local set to enhance structural detail, preserve contextual detail, and to reduce noise. it is based on techniques originally developed for coronagraphs, and involves the decomposition of images into different spatial scales, and the filtering / enhancements of features at the multiple resolutions.    the method is computationally expensive yet
we report on high resolution laser spectroscopic measurements of the atomic hyperfine structure ( hfs ) of high lying states ( rydberg states ) in @xmath1sr and of transition isotope shifts of the stable isotopes @x Math7sr for principal quantum numbers @x math2.   these measurements were done with enhanced accuracy compared to previous results @xcite, in order to obtain sufficiently precise data for accurate comparison of the hfs calculated by means of multichannel quantum defect theory - wavefunctions in first and second order perturbation theory with the results derived from second orderperturbation theoretical analysis. using the casimir formula we find that the second order contributions need to be considered in the analysis of the mqdt - wave functions in orderto explain the unexpected large hyperfine constant@xmath3 and the shift of the hyperfine multiplet, which is responsible for large deviations from the linear dependence in a king plot analysis.
we study a discrete - time random walk on the nodes of a graphene - like graph.   our attention is placed on some mathematical properties of such stochastic process, where the underlying lattice state - space is viewed as a general honeycomb structure ( the hexagonal lattice ). in particular, we give emphasis to the transient distribution of the random walk and its asymptotic behavior making use of the theory of large deviations. by using the grtner ellis theorem,   we obtain closed - form results for the probability generating function and the probability distribution of this type of random walk. moreover, we investigate two different forms of asymptic behavior of the randomly walked states, i.e.  sample path large deviations for general markov processes.
the eigenvalues of the non - hermitian hamiltonian @xmath5 of an open quantum system, which is described by a non -Hermitian operator @x math1, become complex if @x Math0 symmetry is broken.   the results of experimental studies on the basis of a schematical model show that the existence of exceptional points ( eps ) in the continuum of scattering wavefunctions into which the considered ( local ) system is embedded influences not only the eigen values and eigenfunctions of the Hamiltonian in a finite parameter range around its position but also its interactions with another nearby state. as a consequence, the hamiltonians of the open quantum systems lose their spectral relation to the original states of the system ( at low level density ). in the present paper   we try to find out whether or not the results observed experimentally in @xcite are characteristic of@xmath0 symmetry and its breaking or are they solely a property related to the non-hermiticity of the ham Miltonian. using the formal equivalence of the quantum mechanical schrdinger equation to the optical wave equation in @x maths0-symmetric optical lattices,
the string landscape scenario in inflationary cosmology may be divided into many exponentially large domains corresponding to different metastable vacuum states.   the purpose of this paper is to clarify some features of the landscape. in particular, we investigate the properties of the domain walls separating different vacua, how these domains may form, and how large will the fraction of the volume of the universe inside different domains be. using a broad class of static bps domain wall solutions interpolating between different ads or minkowski vacua with unbroken supersymmetry  , we show that the most interesting parts of the string theory landscape correspond to the transitions between supersymmetric ads and minkowskis or ads - minkowis vacua arising from flux compactifications prior to the kklt uplifting, and later introduce the more physically relevant metastable de sitter vacua.
the sagittarius dwarf irregular galaxy ( sagdig ) is a blue, low surface brightness galaxy which was found on the eso and serc survey plates by cesarsky et al.   ( 1977 ) and longmore & lo ( 1997 ) in the 21-cm line with a negative radial velocity. here   we report the detailed ccd imaging of sagdig by using a 2048@xmath132048 ccd detector at roque de los muchachos observatory in la palma island ( canary islands, spain ). for the first time  , we have obtained detailed images of the galaxy in both the @xmath17 and @x Math3 bands with total exposures 2000 s in @x math17 and 1800 s in # 3.7 from the h  i line with the vla. to estimate foreground   galactic star number counts another field ( 8@x maths18 to the east ) was imaged with exposures of 1200 s ( @xMath17 ) and 1000 s ( * 1000 s ).    a total of about 1550 stars were measured in the sagdig frames down to a limiting magnitude @x mathematics19. 	 the integrated
2d semiconductors of group v elements, including phosphorene and arsenene, have been rapidly attracting interest due to their significant fundamental band gap, large density of states near the fermi level, and high and anisotropic carrier mobility.   it is intriguing to see, whether the same can be achieved in iv - vi compounds that are isoelectronic to group v elemental semiconductor monolayers. here  , we study the layered structure of silicon mono - sulfide ( sis ) using _ ab initio _ density functional theory ( dft ) to identify two nearly equally stable allotropes, namely the black - phosphorus - like @xmath0-sis and the blue - phosphate - like@xmath1-sis. both these monolayer structures display a significant, indirect band gap that depends sensitively on the in - layer strain. unlike the nonplanar structure, different sis allotrops show a strong polarization either within or normal to the layers. for the first time, we find that sis may form both lateral and vertical heterostructures with phosphorenea at a very small energy penalty, offering an unprecedented tunability in structural and electronic properties of s
random tessellations * st*able with respect to * it*erations ( stit ) have recently been introduced as a new model for random tesselling in @xmath3 and have quickly attracted considerable interest in modern stochastic geometry.   the purpose of this paper is to establish a second - order and limit theory for the integral - geometric characteristics of stationary and isotropic stit tes sellations in dimensions higher than two by studying the cumulative intrinsic volumes of all orders for the collections of so - called maximal polytopes of@xmath7, which are in codimension 2.0 and above. using martingales and the general theory of martingale problems for pure - jump type markov processes, we show that the asymptotic behaviour of the surface area process dominates and fully determines the first - order geometries of the stittessellation in dimensions larger than two. on the other hand, the limits in law for the second- and third - order properties of the Stitt tesellations are non - trivial and arise from deterministic functionals of the corresponding surface process.
we have calculated the cross sections of the signal for the @xmath2-boson coupling between the photon, the charged goldstone boson, and the@xmath1 boson in the feynman gauge using the tensor integral reduction algorithm van  oldenborgh and vermaseren@xcite.   the results are in good agreement with the results of jikia who has previously calculated a large cross section for transverse @x Math2 s in a nonlinear gauge ( jikian et al., 2015 ). here   we investigate the feasibility of detecting a heavy higgs boson at a photon - photon collider by convoluting the cross section with a realistic photon - photons luminosity from backscattered laser beams. to do so  , we have assumed a top quark mass of @x math10 gev of about 10 gev and a total cross section of 12 independent cross sections for the helicity amplitudes of each helicity mode of the /positivity of the on - shell @x maths2 s. the x - ray energy of the incident photon beams is used to determine whether the beam polarization of the
galaxy clusters are extreme products of structure formation.   they are ideal laboratories to study galaxy assembly, quenching, and sub / super - halo galaxy environments. to leverage a complete picture of cluster formation, we need to find and study also their progenitors at high redshifts that were still forming. in @xcite, we have generated a set of large - scale galaxy density maps of the 1.62 deg@xmath0 cosmos / ultravista field with 30 photometric bands from ultraviolet to infrared. by comparing the data with a matched simulated field incorporating galaxy selection effects and redshift uncertainties,   we have identified a large sample of candidate high - redshift cluster progenitor regions.    our technique recovers two previously known " proto - clusters", suggesting that the algorithm is robust. here  , we present the positions and redshifting of the candidates, together with estimates of their present day descendant masses.
the transient x - ray pulsar v0332 + 53 ( @xcite ) went into outburst in 2004 november, reaching a 1.512kev intensity of @xmath21crab.   a long series of observations by the proportional counter array and high energy x -ray timing experiment aboard _ rxte_ were made throughout the outburst.    we report the discovery of a third cyclotron line at @x Math274kev, along with clear evidence for a non - gaussian shape of the fundamental. 	 the phase - averaged and the phase resolved spectra show that the fundamental is not gaussian, but rather has a non-gaussian shape similar to that seen in other accreting x - Ray pulsars.
the internet is a large - scale, self organized, complex system.   understanding the processes that shape its topology would provide tools for engineering its future. in this work, we investigate the inter - as connectivity as a network formation game with heterogeneous players that may share costs by monetary transfers. to account for the inherent bilateral nature of the agreements between players, we base our model on the heralded fabrikant model @xcite, which was recently extended to include heterogeneous player(s ). using an agent - based approach, we establish an analytically - tractable model, which explicitly accounts for the heterogeneity of players as well as reliability requirements. here  , we show that the results of our study are consistent with those of other recent studies on the network structure of the internet.
we develop a general theory of the dc josephson effect in sns heterostructures with spin - active interfaces.   this theory is based on the analysis of the andreev bound states in such junctions and shows that the josephalic current and the current - phase relation are very sensitive to particular values of (@xmath1 ) spin - dependent interface transmissions, ( @xmath2 ) spins - mixing angles and ( @Xmath3 ) the electron kinematic phase which is essentially set by the product of the fermi momentum and the distance covered by an electron between two scattering events.
the german team handball bundesliga consists of 18 teams where each team has two matches against the other teams, one match at home and one as a guest.   after each season, the teams at the end of the table are replaced in the following season by the promoted teams of the second league. in this study   we focus on a model - free time series analysis of the results of the first ten seasons of the german bundesligas. for this purpose  , we have used the data set of 3060 matches from 2001/2002 to analyze the time evolution of the team fitness, the specific goal distribution and the home advantage which are compared to recently published results for soccer. in addition, we will also analyze the properties of promoted teams and propose an explanation for the success of the best teams.resultsour results can be used to estimate the stochastic contributions which influence a match outcome. these findings allow to present a simple method for the prediction of match results and match winners in good accuracy to the real outcomes. in contrast to the public opinion, we show that the variance of performance differences between handball teams is less pronounced than it has been found for the g German soccer league.
the time delay between two dynamical systems can provide information on conduction velocity, and the nature and origin of coupling, between the processes.   it is necessary to use a well validated method for this purpose. here  , we use a spectral based method, maximising coherence, for the time delay estimation of essential tremor. in order to compensate for the reduction in coherence due to delay, we shift one of the time series keeping the other constant and estimate the coherence as a function of the shift. using this method, we obtain a delay of 11 - 27 milli seconds ( @xmath0 ) between the simultaneously recorded traces of electroencephalogram ( eeg ) and electromyogram ( emg ) of subjects with essential Tremor, a well known pathological form of hand tremor ; and the results are reasonably within the range of experimentally observed value for cortico - muscular transmission @xcite.
the ancillary response file ( arf ) and redistribution matrix file ( rmf ) are commonly used for the analysis of x - ray spectral data.   this work presents a formal derivation of the arf and rmf in terms of the underlying instrumental responses, making a clear connection between the incident source flux and the observed count rate. to this end  , definitions of an arf or rmf are presented that are suitable for dispersive data analysis, and which may be utilized by existing spectral analysis software.. the exposure map is also defined and discussed.
the standard model of electroweak interactions has so far explained all the available experimental data extremely well @xcite. from lep data  , we can witness the agreement between theory and experiment at the level of 1%, which is a striking confirmation of the @xmath9 invariant interactions involving fermions and gauge bosons.   however, some predictions of the standard model have not yet been object of direct experimental observation, such as the symmetry breaking mechanism and the interaction among the gauge boson. in this work   we study the capability of an @x Math0 linear collider, operating in the@xmath1 mode, to search for anomalous four - gauge - boson interactions using the laser backscattering mechanism via the production of a three - gauge bosone, @xcide, and compare the results with those of the experiments performed at the next generation of linear @x math0 colliders ( nlc ) at cern. by comparing the results from the experiments conducted at the nlc and the experiments carried out at lep ii, we show that the latter are more sensitive to the anomalous couplings than the former, and that the effect of the laser Backscattering
the spontaneously breaking of chiral symmetry to a strong magnetic field in quantum chromodynamics(qcd ) is one of the central issues and poses a theoretical challenge.   it has been shown that the chiral critical temperature of the bose - einstein condensation of neutral bosons decreases with an increasing magnetic field, which is in explicit conflict with magnetic catalysis. in the present paper, we extend the above analysis to the relativistic fermions and replace the non - relativists fermionic propagator by the dirac one in a magnetic field@xcite. using the uv cutoff, we find that the critical temperature for the bec at sufficiently low density depends on the magnetic field as well. in weak coupling domain,   the effect of the magnetic fields is stronger than in strong coupling domain where the fluctuations dominate and the situation gets reversed, i.e., thecritical temperature of bec decreases as an increasing electromagnetic field increases. in this case, the results are explicitly cutoff dependent like all relativismic field theories with 4-fermion interactions.
service oriented architectures ( soa ) are typically designed as " tightly coupled " systems based on object - oriented design.   however, they lack the expressive power to model the exchangeable information in more detail. a more robust way to model this information would be to express it as a set of ontologies. here   we describe a method for building ontologies using the @xcite web ontology language ( owl ) and the resource description framework ( rdf - s ). by using these ontologies  , we can model our distributed control system using semantic web standards, and thus make it easier to integrate applications and information sources.
we compare the results of five recent studies using one or more luminosity criteria to estimate the number of gamma - ray bursts ( grb ) with redshifts and derive from each the expected source counts and the euclidean value of @xmath0.   the results show considerable divergence, partly caused by differences in the cosmological evolution of the luminosity functions. for a given luminosity function, the source counts as a function of photon flux can be derived for all five criteria, but the expected counts for n are very flat, probably a consequence of not including any cosmology evolution. at low values of@xmath21 the other four predicted counts are high, only partially caused by the incompleteness of the counts setting in for @x Math22 ph @x maths10 s@x math11.    the eucalyptus value of ~0.0 is used to characterize the observed source counts.
public key cryptographic techniques are based on asymmetric cryptographic algorithms that use two related keys, a public key and a private key.   the international organization for standardization ( iso ) and the international electrotechnical commission ( iec ) have been developing a series of standards for application - independent cryptographic techniques called public key cryptography ( pkcs ) standards for use by secure systems developers world - wide. in this article, we describe the parts and status of the pkrs standards and give an example application which uses these standards.
the axion is a weakly coupled pseudo - goldstone boson which can play a key role in the early universe.   its existence was first proposed by peccei - quinn in the 1970s as a consequence of the strong cp problem, where the ground state of qcd did not respect the @xmath9 symmetry and the effect of instantons on the neutron edm was explained. here   we review the history of the axion and discuss the current state of the art in the field.
spatially extended photoluminescence from a protoplanetary disk at 3.53  @xmath0 m has been observed in the spectra of elias  1 ( v  892  tau ), a herbig ae / be star located in the taurus - auriga complex at a distance of 140@xmath120  pc @xcite.   the source of the emission is unknown, but it is thought to be from small diamond particles that are formed close to the star.
we discuss the intermediate energy color coherence phenomena ( ccp ) in the scattering of protons - vector meson production at tjnaf, hermes and kek hadron facility ( jhf ) energies.   we focus on the effect of momentum transfers point - like ( small size components ) ( plc ) of the hadron wave function on the time development of the optical coherence effects. for the case of a nucleon ejectile coherence,   the main effect is quantum diffusion of the wave packet so that ^plc(z ) = ( _ hard + zl_c  ) ( l_c- z + ( z - l_cs ) + ( x - l+c ). using the fock space decomposition of the light - cone hadron wc wave function over configurations containing different number of constituents, we find that the amplitude of the excited state of the plc - nucleon interaction increases with the distance from the interaction point to the emission site. when the particles are separated by more than a few tens of femtoseconds it is possible to observe the loss of coherence in the transmission of the ejected nucleon.
the nucleon sigma terms are important quantities in resolving the dynamics of qcd, where they help to understand the role of explicit chiral symmetry breaking in the mass of the nucleon.   the strange quark condensate in the nucleus is of significant interest in studies of the qcd phase structure at large baryon density @xcite and in constraining predicted cross sections for dark matter detection@xcite. here   we present a direct calculation of the strangeness component of the pion - nucleon theory using the feynman - hellman relation and the mass extrapolation from experimental results @xmath2@xmath3 scattering. by comparing the calculated value with the experimental data, we show that the calculated result is consistent with both the experimental values and the theoretical values.
the maxwell equations of light are classical, as they do not describe any quantum effects.   so, what changes if we are to use a quantum theory of light?   some may think that the frequency @xmath3 becomes quantized, that is, takes on only discrete values ; others may think the polarization vector@xmath5 becomes a quantum object ; and pessimists may think it is no longer possible to make entangled states of light. in fact, when one quantizes the electric ( and magnetic ) fields, the amplitude of the electric field vector becomes an operator. just as position and momentum of a particle become operators acting on some complex hilbert space when you quantize the particle, so do the electric and magnetic fields become operators in a quantum theories of light by quantizing the frequency and polarization of the electromagnetic field.
a widely accepted mechanism for producing a cosmological gamma - ray burst ( grb ) is the deceleration of relativistically expanding shells.   the kinetic energy of the shells is converted into internal energy by relativistic shocks. in the external shock scenario,   most bursts have a highly variable temporal profile with variability time scale significantly shorter than the overall duration. using a simple model, we have estimated that the hydrodynamic efficiency of this process ( transforming kinetic energy to internal energy ) is about @xmath3. however, kumar ( 1999 ) has argued that the conversion efficiency from the bulk motion to gamma - rays is only@xmath4. here  , we show that if the distribution of the lorentz factor is not uniform, but instead its logarithm is distributed uniformly, then the typical ratio of Lorentz factors between neighboring shells is considerably larger and the efficiency can be close to hundred percents, even for a reasonable spread of lorentZ factors.. the main point of this paper is the possibility of " ultra - efficient " internal shocks.
the study of the statistical properties of dna sequences is of broad interest.   we use two complementary techniques to study the " short - range " statistical properties, namely the detrended fluctuation analysis ( @xcite ) and the mathematical procedure called _ unfolding. in the first technique, we separate the secular trend and the non - secular properties of the sequences. then the nearest neighbour distribution is obtained and analyzed. for two intron - less sequences ( 0% ofons ), humbmyh7cd and dromyonma, corresponding to the human @xmath0-cardiac myosin heavy chain ( mhc ) and   _ drosophila melanogaster _mhc, respectively, we find that the cumulative basis density is a function of the secular part of the sequence and the oscillating one. for the second technique,   the nearest neigbouring distribution is calculated and the results are compared with those obtained by using the same method.. the results show that the nearest neighbor distribution is not always linear but can be used to obtain a universal feature.
the operation of cryogenic ion traps requires high radio - frequency ( rf ) voltages, which are usually generated with the aid of the voltage gain present in rf resonators.   helical resonators are typically used in the frequency regime up to 50mhz, whereas for experiments requiring higher drive frequencies coaxial resonators have been used as well. in cryogenic experiments,   the resonator needs to fulfill different criteria than in room temperature experiments where the resonanceator can be placed outside the vacuum vessel. following the wiedemann - franz law, this results in a low electrical conductivity between room - temperature and the cryogenic parts of the experiment. to minimize the volume of an rlc - series - resonator  , an rf - shield has been designed. in this paper, we discuss the choice of the trap drive frequency, the required voltage gain, and voltage monitoring. in the following sections   we discuss coil design for three types of coils, and in the next section we discuss impedance matching of the resonulator and present an efficient way to match cryogenic resonators.graphical abstract
the progenitor systems of supernovae ( sne ) have been pursued relentlessly over the last two decades, but their nature is still debated.   we show that sn rates per unit mass decrease with increasing galaxy stellar mass in star - forming galaxies in @xcite and g15, and that this effect is independent of galaxy scaling relations and the sn ia delay - time distribution. using a series of galaxy - specific star - formation rates ( ssfrs ), we find that the rate - size relation between sn rates and galaxy mass is stronger for stripped - envelope sne ( se sne ; i.e., those that have had their outer envelopes stripped away before the explosion ) than for other types of sn ( e.g., broad - lined sn   ic ). by combining these results with our previous work on the origin of the sn type ii - plateau ( sne  iip ), which was based on pre - explosion imaging of the sites of the exploded sites of strewn - envelope se sne, we also show that the sfrs of se sne are significantly lower than those of sne ii in ( *?????'s sne  ii in  . ).
gamma - ray bursts ( grbs ) are the brightest electromagnetic explosions in the universe.   these energetic explosions originate from cataclysmic cosmic events, whose  inner engine " that drives the observed emission is confined to volumes mere tens of kilometers across, as indicated by the duration and variability of gamma - ray emission ( e.g., @xcite ). with the near completion of advanced gravitational wave ( gw ) detectors, we will soon be able to directly probe the dynamical processes leading to the creation of grbs, which are less ( or not ) accessible via other messengers. while our theoretical view of gw emission mechanisms connected to grbs is rapidly evolving, the main directions, the opportunities and limitations of observational gw astrophysics are becoming clearer. with this review  , we aim to provide guidance to ( i ) astronomers interested in utilizing the capabilities of Gw measurements to complement electromagnetic or neutrino observations in understanding grbs ; and ( ii ) gw scientists interested in the open questions in grb astrophysics that can be addressed through gw measurements.
we report on the confirmation of an even more exotic, and so far unique, eclipsing binary system in the large magellanic cloud ( lmc ) consisting of a _ pair of classical cepheids in a 413-day orbit.   the system, herein named ogle - lmc - cep-1718, was discovered and identified as a   _ double cepheid _ by alcock et al. in 2008, but it was not yet clear if the two cep heids were indeed gravitationally bound. here  , we present spectroscopic observations of this double - lined system and extract the orbital radial velocity curves of the two components of the system and the individual pulsational radial velocities of the cetheids.    we add new photometric data from ogge iii and ogne iv surveys to the radial velocity data to obtain the orbital solution as well as a determination of several physical parameters of the coeval cepheterids, particularly their masses and pulsation modes.. the results show that the two star systems are separated by a distance of about 1.5 billion light years and that they both exhibit eclipsing variability.
abstractthe past activity of Sagittarius a@xmath0 is still poorly understood, but it is known that it experienced a large phase of activity in the past ( @xcite ) and its recent history can be reconstructed from the non - thermal emission emanating from the molecular clouds at the galactic center.   this emission is characterized by a continuum component and a strong  line at 6.4  kev, which we show is due to reflected emission from the supermassive black hole. using high spatial resolution, we have measured the fine x - ray variations occurring in a key region located between  and the radio arc, hereafter called the sgr  a complex, and show that the five main molecular clouds of the region are varying with a significance of at least @xmath6 but with two different types of temporal behavior : the variations are either short ( year and peaked ) or slower ( decade and linear ). since the time scale of the illumination is directly linked to the clouds position along the line of sight, the temporal behavior of the variation can be used to constrain the matter distribution and thereby to further characterize the past activities of. here   we present here our main results concerning the temporal variations observed
the dynamics of entanglement, for a wide class of entangled states, have been extensively analyzed and experimentally demonstrated in @xcite.   the results show that the dynamics of Entanglement depends intrinsically on the system - environment dynamics and the quantum entangled state under consideration. besides a more general treatment restricted to a two - qubit case given in@xcite, all analysis has restricted themselves to particular initial entangled states evolving under some specific dynamics.. we show here that the comparison between the effect of the environment on the many kinds of entageneration for a multipartite system, used as a resource for a given task, and the effects of decoherence on how well the task is achieved indicates which type of entanlement is relevant for accomplishing it.
damped ly@xmath1  systems ( dlas ) are used to trace chemical evolution in neutral gas over a large fraction of a hubble time.   the observed cosmic abundance spread at a given epoch is attributed to two distinct effects : ( 1 ) lines of sight to background qsos probe a single location in dlas at a random impact parameter, so gradients in dla abundances will produce different abundances and dust - to - gas ratios, and ( 2 ) dlas arise in a variety of galaxy types with different star formation and enrichment histories, as observed at low redshift. here  , we investigate the nature of dlas probed by two or more lines of view toward he0512@x Math23329 , a double image qso at @xmath23 n to e, with the brighter component ( herafter a ) to the north. using spatially resolved spectroscopy, we find that the metal abundances in the dla observed along the two lines of line of sight toward this quasar are very different, with an average value of ~2.5  g / cm3 for /yr for the stronger component at
internal cluster target facilities  such as cosy-11  @xcite installed at the cooler synchrotron cosy - jlich  allow the study of the production of mesons in the proton - proton interaction with high luminosity in spite of very low target densities.   an exact extraction of absolute cross sections from the measured data demands a reliable estimation of the acceptance of the detection system, which depends on the accuracy of the determination of the position and dimensions of both the beam and the target. here   we describe a method for estimating the dimensions of the accelerator proton beam, based on the momentum distribution for elastically scattered protons, which can be measured simultaneously with the investigated reaction. using the cosy11 detection system    as illustration, we show that the average smearing of the missing mass originating from the produced mesons is on average larger than expected, indicating that the detector resolution is not sufficient to extract the true width of the measured reactions. however, if the target and beam dimensions are known, it is possible to determine the average size of the reconstructed momenta and hence the natural width of these reactions, provided
a new monte - carlo method for modelling radiation  matter interactions in smoothed particle hydrodynamics ( sph ) is presented.   the method uses the sph density field directly, thus preserving the " native " resolution of the code. to test the accuracy of the method, we study the radiation pressure effects on the gas equation of state in a gaseous system modelled by an sph code using a new photon packet based radiation transfer scheme combined with an ansatz. here   we show that the method is very accurate and reproducible, and can be used to model the radiative heating / cooling and photo - ionisation processes in the field of galaxy and star formation.
the ferromagnetic ground state in the @xmath0-@xmath1 hubbard model on a square lattice is investigated by incorporating correlation effects in the form of self - energy and vertex corrections within the goldstone - mode preserving inverse - degeneracy expansion scheme.   the results show that the quantum corrections to the magnon propagator provide a strong magnon - damping mechanism for modes lying within the stoner gap,@xcite whereas magnon damping within the random phase approximation is only due to decay of collective excitations into single particle stoner excitations.
the growth of a crystal surface on a substrate with a correlated disorder @xcite is studied in the context of a nonequilibrium growth problem.   the non - equilibrium shape of the growing surface is characterized by a roughening transition from a rough high temperature phase to a smooth low temperature phase as the temperature is decreased. for the disorder substrate,   this transition is replaced by a super roug hening transition which is due to a nonlinear response of the system to an external force. using a renormalization group treatment of the growth on a monolayer of@xcite with a short range correlation of the disorder of the lattice, it is possible to go from the pure to the short range disorder limit and the scaling properties of the surface are the same as that of a surface growing on a pure substrate, in the rough phase.
in a recent paper  @xcite, it has been proposed that large arrays of aligned carbon nanotubes ( cnts ) might be of use for the directional detection of dark matter ( dm ) weakly interacting massive particles ( wimps ).   the purpose of this paper is to illustrate the dynamics in these regions and, by means of monte carlo ( mc ) simulations, to provide an evaluation of the efficiency of a large number of cnt arrays as the target of a directional dm detector. at the same time, the results obtained here give more strength to the proposal presented in @xcite and give important suggestions on how to devise the cnt array to maximize the wimp detection.
the evolution of the size and number density of disk - dominated galaxies in the chandra deep field south ( cdf - s ) region has been studied using the multi - wavelength ( @xmath11 )   hst_/acs images from the goods program.   we derive the structural parameters of the galaxies through a two - dimensional modelling of the surface brightness distribution using the galfit software and use a single sic ( sic 1968 ) function to model the brightness profiles, and used simulations to verify that the sic index,@xmath22, can provide a reliable classification of the bulge - dominated and disk -dominated galaxies even at the faint magnitudes. for the large disks with scalelengths greater than @x Math10 kpc,   the abundance and size distribution remain constant out to @x math9, while for the small disks with scales of ~1.0 - 2.0 kpc there is a significant increase in the number density as the magnitude of the redshift increases.    the results are consistent with the cosmology defined by the magnitude  size relation between the distributions of the galaxy mass and the space densities.
abstractto investigate the geometry and physical properties of the molecular gas in the circumnuclear region of ngc  1052, we have performed high - resolution observations toward hcn ( 10 ) absorption lines with the korean vlbi network ( kvn ).   we show the first parsec- and subparsec - scale hcn(10 ) maps of the central active galactic nucleus ( agn ) by using a milliarcsecond ( mas ) resolution of 3  mm at 3.5  mm. to achieve this resolution, simultaneous dual - frequency data at the k   ( 2170021828 mhz ) and w ( 8864388871 mhz) bands were recorded using the kVn for a total on - source time of 7.5 hr. among the ionized gas molecules,   the most abundant is neutral atomic hydrogen ( ), oh, hco@xmath11, hcn, co transitions are found toward the center as absorptions @xcite, redshifted with respect to the @xmath10-like h@x Math9o maser emission. besides those transitions, several atomic and molecular gases are also found near the
circular polarization ( cp ) is a very small fraction of the integrated synchrotron emission from extra - galactic radio jets.   low resolution measurements made during the 1970s and early 1980s showed circular polarization to be only a few orders of magnitude stronger than intrinsic cp. in this article   we discuss the study of circular polarization in jets using very long baseline interferometry ( vlbi ), and we present new multi - frequency vlba images on two quasars : pks 0607@xmath0157 and 3c345, and evaluate the extent to which our interpretation of these results is confounded by the inhomogeneous cores in which the circular polarization is detected.
the clio ( cryogenic laser interferometer observatory ) project @xcite is a prototype of the lcgt ( large - scale cryogenic gravitational telescope ) project.   the goal of clio is to construct an interferometry in kamioka mine ( gifu prefecture, japan ) and to demonstrate thermal - noise suppression by cooling the mirrors. at this silent site, stable operation with lower seismic noise   is possible because of small seismic motion.. the clio interferometers have two 100 m length fabry - perot cavities which consist of four sapphire mirrors. these mirrors and their suspensions are cooled by silent pulse - tube cryocoolers developed for clio@xcite. as a result, the temperature of these mirrors must be below 20 k. light from a laser source passes through a 10 m mode cleaner, and is divided by a beam splitter for the two cavities ; the reflected beams by the two Cavities are not recombined. the inline cavity, into which the light transmitted by the beam splider goes, is used for laser frequency stabilization. during the construction of the tunnels for the monte carlo detector,   all vacuum chambers
data compression plays an important role as one of the base technologies in many aspects of information transmission.   the theoretical framework for lossy compression scheme is called rate distortion theory, which consists partly of shannon s information theory and is a cross - disciplinary field that combines information theory with statistical mechanics. here  , we present a new method for analyzing the performance of tree - like committee machine and parity machine as typical multilayer networks by comparing their performance with that of low density generator matrix ( ldgm ) code and using a nonmonotonic perceptron ( nmt ) as a special case.
we have developed a microscopic " dimpled " silica optical fiber taper evanescent - coupler that is designed for rapid, wafer - scale diagnostic testing of on - chip photonic components such as waveguides and resonant filters.   the probe is made from a standard straight fiber tapers that are pressed against a silica mold and heated by simultaneously heating and pulling standard telecommunication fiber ( specifically smf-28e ). by increasing the tension in the taper,   fluctuations in the measured taper - chip gap can be greatly reduced to levels comparable to those observed with tensioned straight - taper probes. to demonstrate the utility of the dimpled taper optical probe, we demonstrate the characterization of two types of devices on a silicon - on - insulator ( soi ) wafer platform : a dense two - dimensional array of high-@xmath0 silicon microdisk resonators and a planar microring resonator. at the center of a 5@x Math25 array, the dimpling taper probe is critically coupled to a microdisk but not to a nanometer - sized resonator, but it is able to conduct direct coupling to the resonant filter
we study spaces satisfying the curvature - dimension conditions _, @xmath0spaces, which generalize the notion of a lower ricci curvature bound to metric measure spaces.   we show that these spaces reproduce behavior characteristic of riemannian manifolds better than the other conditions and that the inclusion relation between these spaces can be written as @x Math17 riemanian manifold with weighted volume measure and alexandrov spaces with the hausdorff measure.
we propose a new model for the modelling of unsteady mixed flows in closed pipes with non uniform sections, where some parts of the flow can be free surface ( it means that only a part of the pipe is filled ) and other parts are pressurized.   the transition phenomenon between the two types of flows occurs in many situations such as storm sewers, waste or supply pipes in hydroelectric installations and can be induced by sudden changes in the boundary conditions as failure pumping. here   we present a new unidirectional shallow water model which takes into account the cavitation problem and air entrapment. using the same couple of conservative unknowns as in @xcite, we propose a model for mixed flows, that we call * pfs*-model. to obtain this model, we adapt the derivation of the free surface model from the @xmath0d _ incompressible _ euler equations which are written in a suitable local reference frame ( following@xcite ) in order to take into consideration the local effects produced by the changes of section and the slope variation. writing the source terms of these two models, * p * and * fs*.model, into a unified form and using
the origin of nuclear x - ray emission in radio - loud agn has been a topic of considerable debate.   it has been unclear as to whether the emission primarily originates in an quasi - isotropic accretion flow, or instead is associated with an intrinsically beamed parsec - scale radio jet. here  , we show that the presence of heavily absorbed, accretion - related, nuclear x-ray emission in the mid - ir band of the 3crr catalog of radio galaxies drawn from the redshift range @xmath0 is strongly correlated with the observed luminosities of the accretion disk and the central supermassive black hole ( seyfert 2s ), and that the source of this emission is a low - excitation radio galaxy ( lerg ), rather than a conventional radio - quiet one. by contrast, the existence of a strong optical line - emission can be inferred from the broad - line region ( blr ) and narrow - line regions ( ng ) of the same galaxy, which are dominated by a dusty ` torus'that obscures the view of the optical continuum and the blr due to the absorption of light from the accreted cold matter
we study the energetically preferential positions of disclinations in a nematic thin film assigned on a gaussian bump.   it is found that disclinations with a @xmath0 charge prefer positioning at inflection points of the bump, implying the formation of a halo, i.e., an annulus distribution of excess disclinations around the top of the bumps. for those with a@xmath1 charge,   the halo structure is more complex, with disclinations exhibiting double concentric halo structures. these halo formations are consequences of the non - trivial coupling between the disclination energies and the surface curvature modulation.
the effect of the laser - field  induced dipole moment on the profile of angular distribution of photoelectrons emitted in the process of a single - photon ionization from a strongly polarizable target exposed to a laser field is investigated.   numerical results are presented for sodium cluster anions na@xmath5 with @xmath6, which are characterized by large values of the dynamic dipole polarizability ( i.e., in the vicinity of plasmon resonances ) and for comparatively low intensities ( e.g., 0.47 ev at the photon energy of na+/cs+ ) of their laser field. as a result  , we demonstrate that dramatic changes to the profileof angular distribution occur in vicinities of the plasmorient resonances and for relatively low intensity ( < 1 ev ) of the lasers field.
quantum open systems have been a subject of fundamental interest for many years.   quantum open systems are often used to construct models of practical interest, in particular to account for line shapes in epr, nmr and laser spectra, to evaluate chemical reaction rates and electron and charge transfer rates, and to explore the lifetimes of quantum entanglement states in quantum information theory. in this review,   we will focus on the applications of quantum open system theories to the study of optical multidimensional spectrum dynamics.
we have recently given a combinatorial model for the irreducible characters of a complex semisimple lie group @xmath1, and, more generally, for the demazure characters @xcite.   this model was defined in the context of the equivariant@xmath2-theory of the generalized flag variety. here  , we extend this model to complex symmetrizable kac - moody algebras. instead of alcove paths ( that make sense only in finite types ),   the present paper is based on @x Math0-chains, which are chains of positive roots defined by certain interlacing conditions. these new objects extend the notion of a reflection ordering @xaite, and have many interesting combinatoria properties, some of which are investigated in this paper.. the extension from the finite to the infinite case is nontrivial since the description in terms of the affine weyl groups and alcoves is no longer available in the latter case.    compared to the geometric approach in @xcites, the generalization in this article is carried out purely in the contexts of representation theory, and new features of
strong gravitational lensing of background objects by massive clusters of galaxies is expected to produce multiple images with wide separations, @xmath0, and the multiple images of background lensed galaxies have long been known with radii of giant arc systems up to@xmath1 ( e.g. @xcite ).   we have searched a catalogue of 22,163 qsos that comprises the recently completed 2df qso survey ( " the 2qz survey " ) for candidate wide - separation lensed qso systems and have obtained higher signal - to - noise spectra in an attempt to eliminate obvious non - lensed systems and to identify systems that are likely to be genuine lensed system. after an incomplete survey of the most likely candidates, there remain six systems which, with varying degrees of confidence, arelikely to be lensed.
the giant metrewave radio telescope ( gmrt ) facility @xcite has been used to study the possibility of detecting ultra high energy ( uhe ) radio waves from the moon using the askaryan effect.   this effect causes electromagnetic cascades, induced by the uhe particle interactions in dense media, to develop a negative charge excess, which will radiate coherently at radio wavelengths, thereby producing strong coherent pulses of erenkov radiation. among the various methods for detecting uhe particles, a promising technique utilizes the askyan effect. here   we report on the detection of uhecr and neutrino radio waves originating from the lunar regolith with the gmRT.    the experiments were carried out using a single 64 m diameter radio telescope equipped with two fully steerable dishes spread over distances up to @xmath10 km@xmath11 km in a compact array while the rest are spread out in an approximate " y " configuration.. the results show that the first experiment was successful in detecting signals from uhe - induced radio waves in the 500-mhz band centered at 1.425 ghz after making appropriate corrections for the ionospheric delay between two sub -
the purpose of this study was to investigate the differences between the problem solving strategies used by graduate students ( experts ) and introductory physics students in order to categorize problems.   we asked 21 physics graduate students to group 25 introductory mechanics problems into categories based on the similarity of their solutions. unlike graduate students who categorized problems based on physical principles involved to solve them, introductory students categorized problems involving inclined planes in one category and pulleys in a separate category. here, we discuss the process and outcome of the categorization of 25 introductory mechanic problems by 21 physicists graduate students enrolled in a teaching assistant training course at the end of the course from their own perspective and later from the perspective of a typical introductory student. although the graduate students performed the categorizations correctly, they claimed that such a task is  useless ",  impossible ", and   has  no bearing " on their teaching assistant duties. using these findings  , we suggest that inclusion of such tasks can improve the effectiveness of teaching assistants training courses and faculty development workshops and help teaching assistants and instructors focus on issues related to teaching and learning.
the present work aims at exploiting the fact that quantum ratchets can be used to transport quantum states and thus distribute entanglement between distant nodes, a basic task for quantum information and computation purposes.   we illustrate this with a particular and simple implementation of quantum state transport based on two - level bosonic ultracold atoms in optical superlattices. using a translationally invariant modulation of the superlattenice,   the quantum state is transferred between two arbitrary lattice sites using a bose - hubbard hamiltonian that models the dynamics of the atoms. by taking into account many - body interactions, we find that it is possible to induce directed transport with arbitrary speed without breaking the translational and time reversal symmetries in the forces.
the collapsar model @xcite was originally proposed as an explanation for common, " long - soft " gamma - ray bursts ( grbs ) with durations near 20 s. it is well known, however, that forming a disk so quickly requires an unusually large amount of angular momentum to be stored in the core up to the point when the star dies.   black holes are expected to form in a significant fraction of massive star deaths and it seems possible that, in at least some of these, the black hole will form without generating an outgoing shock. here   we explore the possibility that these black hole systems form an accretion disk, but only after almost all of the star has accreted into the hole. because the outer layers of theStar take longer to fall in - months to years in the case of a red supergiant -   the duration of the transient produced by accretion through a disk in these cases is much longer than for the common grbs studied so far.    we consider four varieties of long duration transients categorized by the kind of system where they occur : 1 ) single supergiants with metallicity less than about @xmath4 and low mass loss (
spin glasses are magnetic materials in which spins are randomly frozen.   a number of facts are now known about the static properties of spin glasses, and yet many problems still remain to be solved, particularly in finite dimensions. in the present contribution   we show that the well - known technique of duality transformation, in conjunction with arguments using gauge symmetry, enables us to predict the exact ( correctly speaking, possibly exact ) location of the multicritical point, where the ferromagnetic phase ceases to exist in the phase diagram, not only in the two - dimensional @xmath0 ising spin glass but also in other systems in two, three, and four dimensions. by means of this method  , we find that the spin glass phase can be identified at the same location in all the cases studied so far.
we analyze the properties of the single qshi / metal interface as well as the interplay between edge states and bulk states in metal / hgte / metal junctions.   we show that the conductance signals originating from the bulk and the edge contributions are not additive. for a long junction the transport is determined by the edge states contribution, while for a short junction theconductance signal is built from both bulk and edge states in the ratio which depends on the width of the sample. to test the robustness of conductance maximum in the presence of scalar disorder  , we use tight - binding calculations to test its robustness against disorder.
large - amplitude longitudinal ( lal ) oscillations in prominences are thought to be triggered by an energetic event.   several models have been proposed to explain the restoring force and damping mechanism of the lal oscillations, but most do not successfully describe the thread motions. in this work   we use a full wave description of the oscillation, expanding our previous investigations. using a model of the filament flux - tube geometry as composed of up to 3 curved segments, we show that the oscillations of threads forming the basic components of a prominence in a sheared arcade are strongly related to the curvature of the dip magnetic structure of the flux - tubes. when the magnetic field is slightly curved by the prominence weight, the resulting thread motions are similar to those observed in the literature.
the topological theory of spiral wave is a new method which can directly deduce these spiral waves in a precise topological form, and can reveal the inner structures and the branch processes ( generate, annihilate, encounter, split, or merge ) of the spiral waves. by making use of _ _ duan s topological current theory,   we study the inner structure of Spiral wave in details.   it is showed that the center of spiralwave is not only classified by topological charge, but also classified by hopf index, brouwer degree in more detail in geometry.    we also investigate the evolution of spiral Wave using the topological model.. and one sees that the spiralwaves generate or annihilate at the limit points and encounter, Split, or Merge at the bifurcation points of the phase field., furthermore, we summarize the topology constrains on the behaviors of spiral waves during the above processes.
reliable prediction of durability of structural components and assemblies is a fundamental requirement in various branches of engineering.   one of the difficulties arising in the way of applying this methodology is the fact that in the process of assembly materials undergo additional processing operations that modify their internal structure ( e.g. grain size and texture, composition ) and internal load distribution ( residual stress ). here   we present a new method for the determination of residual stress from x - ray diffraction measurements of a polycrystalline sample of welding - induced tensile strength. using the @xmath0 technique,   the residual stress state of the test piece is determined in the plane of the experiment, and the results are used to develop an elastic finite element numerical model of the testing piece. as a result  , the model can be used to predict the durability of the assembly in the presence of residual stresses.
the self - supporting localized patterns in bose - einstein condensates ( becs ), which are frequently called matter - wave solitons, have been the subject of many theoretical and experimental works.   they are generally created in ultracold gases with repulsion between atoms, and are characterized by the balance between the repulsive nonlinearity and negative effective mass of the matter waves, induced by the quasi - one - dimensional optical lattice ( ol ) applied in the axial direction @xcite. here  , we report the creation of a binary bec with the ( natural ) intra - species self - repulsion, while the inter - species interaction is switched to attraction. using the feshbach - resonance ( fr ) technique, we show that the self - attractive interactions between atoms in the bec trapped in the ol can be tuned to a small negative value, thus providing for the weak self - attractivity necessary for the formation of solvent - supported localized patterns. as a result,   the observed pattern is consistent with the concept of a pair of quantum dots, which may be used to trap fermion atoms in a binary degenerate fermi gas, supported by the attraction between
the origin of the narrow iron k@xmath0 emission line at @xmath4 6.4 kev in the x - ray spectrum of most active galactic nuclei ( agns ) is still poorly understood.   reverberation mapping of broad line regions ( bls ) of seyfert 1 nuclei is one of few methods that can directly derive the masses of super - massive black holes ( smbhs ) in agns. here   we use this technique to compare the virial products of the infrared time lags and the narrow ferromagnetic lines for 10 type 1 agns with the black hole masses from other techniques, including the mass of the blr gas and the diameter of the outermost regions of the accretion disk. by comparing the results of these two techniques, we find a strong correlation between the width of the broad emission line and the size of the smbh mass, which is consistent with the theory that the inner radius of the torus is about a factor of two narrower than the broad emissions.
the scaling analysis of experimental data in high-@xmath0 superconductors ( htsc ) is a simple but powerful tool in elucidating the underlying physics without invoking a specific model.   recently, we found that the temperature dependence of the c - axis resistivity @xmath1 of hTSc obeys a universal scaling law given by@xcite where @x Math3 is a doping dependent coefficient, @x math4 is temperature, and @x maths5 is the pseudogap. here  , we apply the scaling analysis to the experimental data of multilayer htscs using the anisotropic interlayer hopping integral @xcite and the @xMath6-like symmetry of the pseudo - geometries of the pseudogsap. for the in - plane resistivity,   the results show that the thermodynamic properties of the  function are determined by the interplay between the aniostat of the hopping integral and the symmetric symmetry of this pseudogapped energy scale. as a result, the solution of the scaling problem is solved by combining the results of the previous scaling analysis with the measurement data of the quantum critical fluctuation
@xcite is a novel method for sequencing dna by measuring the transverse electronic current as single - stranded dna ( ss - dna ) translocates through a nanopore.   the concept envisions a device with embedded nanoscale gold electrodes that can be used to measure the current as the nucleotides translocate through the pore, allowing the dna to be directly sequenced by detecting specific signatures of individual bases. in previous work, however, it was assumed that each measurement could be performed almost instantaneously. in this paper   we examine the fact that, contrary to naive expectation, the measurement bandwidth of the electrical probes reduces these overlapping distributions into sharply peaked and disjoint distributions, rather than just limiting the sampling rate. using all - atom molecular dynamics simulations coupled with quantum mechanical current calculations  , we find that although the overall magnitude of current can change dramatically, the intrinsic distinguishability of the bases is not significantly affected by pore size and transverse field strength.
we report the results of radial - velocity follow - up observations using subaru 8.2 m telescope for two of the _ kepler _ evolved stars, kepler-91 ( koi-2133 ) and Koi-1894 ( koa-18 94.01 ).   thanks to the high precision in their radial - velocities measurements, we independently confirmed a jovian planet previously reported around one of the planets identified by @xcite and newly found a hint for the existence of an additional companion in the system. also, we detected a possible sub - saturn - mass planet around the other planet with 23@xmath4 confidence level.
we investigate whether anharmonic effects in the trapping potentials or the coulomb interaction between the ions in a linear paul trap can cause inaccuracies in a quantum simulation.   we consider a chain of ions in such a trap, which uses a combination of static and frequency - dependent fields in order to trap ions. as the precision of these experiments grows, one needs to examine perturbations of these systems that carry them away from the simplest ideal. here  , we show that there is an intrinsic anharmonicity that arises due to the coupling tensors that arise from the anharmonal nature of the ion - trap coulomobomb interaction. by taking advantage of this an Harmonic effect, we find that the spin exchange couplings between the trapped ions are more accurately described by a static pseudopotential approach, when the ion equilibrium positions lie at the nulls of the potential energy surface. using numerical results, we also show that the theoretical model of the system can be approximated by means of two - dimensional quantum simulators.
conformal field theory ( cft ) is a powerful tool for the study of critical phenomena in two dimensions, but it has some limitations.   first, it deals primarily with correlation functions of local operators, and is therefore not always the best tool to investigate other quantities. given some critical lattice model, there is no way, within the theory itself, of deciding to which cft it corresponds. also, the methods of cft, although very powerful and successful, are generally speaking not completely rigorous from a mathematical point of view. in this paper  , we review the most recent developments in the area of two - dimensional critical phenomena that have emerged in the mathematics literature and have followed a new direction, which has provided new tools and a way of coping with at least some of the limitations of c ft. these new developments came on the heels of interesting results on the scaling limits of discrete models, but they differ greatly from those because they are based on a radically new approach whose main tool is the stochastic loewner evolution ( @xmath3 ), which focuses directly on non - local structures that characterize a given system, such as cluster boundaries in ising, potts and percolation
we analyse the effective field theory ( eft ) of the standard model ( sm ) higgs boson for a wide class of weakly coupled renormalisable new physics models extended by one type of scalar field(s )  -a and -c.   we find that only a few types of interactions contribute to the higgs dimension-6 operators, which are obtained by integrating out the heavy degrees of freedom of the sm higgs and electroweak gauge fields into the eft. in this framework, we show that these interactions are more generic and, after the heavy scalar fields are integrated out, give rise to dimension-six operators at one - loop level. using the same approach, we work out the effective operators and the associated wilson coefficients for an arbitrary new scalar Field for which the scalar sector is augmented from the sm by one new scalor field. as a test case, we study some benchmark models of uv - complete models with a broad range of electroweak precision observables.
the cannonball ( cb ) model of gamma - ray bursts ( grbs ) is a very explicit elaboration of the original proposal by shaviv and dar ( 1995 ) : that the @xmath0-rays of a grb would be generated by inverse compton scattering ( ics ) of stellar light by the electron constituents of transient narrow jets, emitted in stellar processes leading to gravitational collapse.   the observed superluminal motion of the source of grbs and their afterglows ( ags ) relative to " fixed stars " has been proposed as a possible consequence of this theory. in this note   we concentrate on a cb - model prediction which is not ( to date ) a standard - model one, the apparently superluminous motion of an apparently close - by grb with sufficiently bright ( radio ) ags.
x - ray parametric down - conversion ( pdc ) is an intriguing second order nonlinear process where an x - ray pump photon of energy decays spontaneously into two photons, the idler and the signal.   we present here a renormalization factor @xmath11 that captures the behavior of the nonlinear susceptibility at the@xmath0-absorption edge of diamond and at the @x Math1 absorption edge of si. the factor @Xmath11 is derived by using the renormization - group method that describes the variation in the effective coupling constant under changes of scales @xcite, and the method of dispersion relations applied to the atomic scattering factor.    the theoretical results are presented and compared with the experimental results in sec. 	 v. important predictions of our model and the conclusions are reported in sec!   v.
we present a deep long - slit spectroscopic observation of cfhqsj2329 - 0301 ( g09 ), a quasar at @xmath1 discovered in the canada - france high - z quasar survey.   we show that the emission of ly@xmath0  photons from this quasar is spatially extended at the @x Math12 band and possibly also at the #13 band.    the observed extended emission is due to the accretion of cold gas into the galaxy by the supermassive black holes at the quasar center. as cold gas falls toward the central galaxy   it can be heated and ionized by shocks and recombines emitting Ly@x math0  photon.. the results of this study are discussed in terms of the cosmological evolution of this galaxy.
the term rotational doppler effect ( rde ) is used to describe a frequency shift encountered by a receiver of electromagnetic radiation when either the receiver or the source of the radiation are rotating.   the rde is less commonly known than the conventional dopple effect, but it is still important for the use of rapidly spinning samples in nuclear magnetic resonance ( nmr ) technology.    the r de can be explained by the fact that the frequency of the circularly polarized electromagnetic wave measured at a given point in space corresponds to the angular velocity of the rotation of the electric ( magnetic ) field due to the wave ; the frequency shift caused by the rdes is due to relativistic time dilation for a receiver moving tangentially with respect to the source.see research article http://www.biomedcentral.com/1471-7007/9/8/11
the quantum spin hall ( qsh ) phase in graphene is preserved for energies below the qsh gap, even for extremely strong magnetic fields or in the presence of disorder.   we show that this property can be traced back to the peculiar " relativistic " aspect of the quantum hall effect in graphene and to the existence of a robust state, localized at the interface between the two topological insulators, which is analogous to the ambipolar  snake " states which arise in graphene quantum hall junctions. here  , we demonstrate that this state can be used to realize a topologically protected spin - polarized charge - current switch in graphene.
the advent of sensor network technology provides a variety of applications that have been considered unrealistic in the past.   one such application is in the area of space communications : with ad hoc sensor networks, a number of sensor nodes randomly placed on a planet can collaboratively collect information and then, also collaboratively, send the information back to earth. in this scenario, the sensors must have the ability to transmit information over very long distances with high energy efficiency. in general,   this can be achieved by adaptive beamforming. given several well - designed antenna elements at the transmitting / receiving sensor nodes, each node could in principle autonomously transmit / receive the information to / from any desired direction. however, considering the fact that each antenna element requires analog circuitry ( and thus leads to costly hardware ), in practice each distributed sensor is likely to be equipped with only a single antenna and this precludes the use of autonomous beamforming in scenarios of very energy efficient communication. here  , assuming idealized channel model conditions and antenna properties, we analyze the achievable performance of collaborative beamforming based on distributed sensor nodes in a probabilistic sense. specifically, the statistical properties of the achievable beampattern of the random sensor arrays are studied based
rotochemical heating is a heating mechanism that is important for old neutron stars with fast rotation and low magnetic fields, features that are characteristic of millisecond pulsars ( msps ).   the most striking prediction associated with this mechanism is that, if the spin - down timescale is substantially longer than any other timescale involved ( with the likely exception of magnetic field decay ), the star arrives at a quasi - equilibrium state, in which the temperature depends only on the current, slowly changing value of @xmath1 ( the product of the angular velocity and its time derivative, proportional to the spin-down power ), and not on the star s previous history @xcite. in this work, we calculate the thermal evolution of msps with rotochem heating, taking the structure of the star fully into account in the frame of general relativity, and using realistic equations of state of dense matter. by doing so  , we develop a general formalism to treat the evolution of the temperature and departures of chemical equilibrium in the same way as in the case of experiments.    we find that the rate of these processes is much slower than observed observations, and that the temperature decreases linearly with the increase in the number of
the brain is a computational device for information processing and its flexible and adaptive behaviors emerge from a system of interacting neurons depicting very complex networks.   many biological evidences suggest that the neocortex implements a common set of algorithms to perform " intelligent" behaviors like learning and prediction. in this work, we propose a learning framework based on these biological considerations, called inductive conceptual network ( icn ), and we tested the accuracy of this network on the mnist and usps datasets. as a preliminary step  , we introduce few theoretical concepts about learning and memory experiences in nervous systems. here   we first present crucial aspects of brain information processing : the human brain massively elaborates sensory information. through some elusive mechanism, the brain builds models ( formal representation from observations ) from observations. in such models, pattern recognition and abstraction play a crucial role @xcite. by modeling node inputs by variable - order markov models ( vmms ),   the invariant pattern recognition that occurs in the hierarchy nodes is achieved by modeling input nodes by modeling them by vmms. using the new learning framework, we show that the performance of the proposed network is comparable to that of the memory - prediction framework.
in 1993 an outbreak of a severe disease now known as hantavirus pulmonary syndrome ( hps ) struck the region of the four corners, in the north american southwest, with a mortality in excess of 50% of those affected.   the main host of the virus was identified as one of the most common mammals in north america, the deer mouse, _   peromyscus maniculatus_. since then, continuous efforts in different areas of science have been made to understand this epizootic, with the ultimate goal of correctly assessing the risk to humans. here   we present a simple mathematical model for the spatio - temporal patterns in the spread of this epiphyseal infection, which is based on the model of abramson and kenkre ( henceforth mentioned as the ak model ). among the consequences of the mathematical model that have correlations with the field observations, we mention the sporadic disappearance of the infection and the formation of " refugia," wherein the infection spreads  when conditions change  in the form of waves.
the cosmic reionization is an issue of great significance in cosmology in relation to the formation of galaxies.   the information on the ionization states has been accumulated by the observations of ly@xmath0 absorption lines in high redshift qso or galaxy spectra. here, we simulate qso absorption lines by using the results of 3d radiative transfer calculations and compare them to observations at high redshifts. also, the collapse of pregalactic clouds in a reionized universe is explored in relation for protogalaxies in uv background radiation.
in the random - energy model developed by derrida @xcite for the theory of spin glasses, the thermodynamics of long flexible polymer chains in the vicinity of the self - attracting self - avoiding walk ( sasaw ) point are perfectly captured within the lattice model of self- and self - avoided walks.   a subject of great interest is the study of conformational transitions of heteropolymer chains, containing monomers of essentially different chemical nature. here  , we present a generalization of this model by assuming the interaction energies of all the couples of monomers along the chain to be independent identically distributed quenched random variables ( so - called random - bond model  ). as a consequence, we find that the ability of a chain to fold into a compact state is dependent both on the composition ( the fraction of residues of each type ) and on the sequence of residues ( e.g., the number of residues in the chain ) of the monomer sequence. at the temperature below the @xmath7-point the polymer radius shrinks, which causes the collapse transition into the compact globule - like conformation regime.
large-@xmath10 supersymmetric yang - mills theories ( sym ) are promising candidates for nonperturbative formulations of the superstring theories. in this paper, we study two - dimensional @xmath0 @x Math1 sym on two - torus using sugino s lattice regularization.   the restoration of supersymmetry without fine - tuning has been tested extensively by using the monte - carlo simulation. to study the phase structure of the gauge theory at strong coupling, we extend the planar limit of the sym to the Planar Limit of the hypertonic space.
the surface current method is generalized for problems of plane waves diffraction and transition radiation generated by a charged particle on an ideally - conducting surface.   the field of a scattered wave is represented as a radiation field of the surface current formed by the dipoles disposed on an ideal - conducting screen @xcite. in order to get the right result for these problems, it is necessary to have a non - zero component of the surfaces current density which is normal to the screen.    the method developed leads to the well - known integral equation for the surfaceCurrent density induced by an incident field @xcites.. this method is also used to consider transition radiation, arising when a charged particles crosses an ideally- conducting screen. however, if the incident field satisfies the inhomogeneous maxwell s equations, this method turns out to be approximate @xmath2/x = 0.1. 	 this rather unexpected fact may be explained taking into account the derivation of this equation using the so - called double - current layer formulation@xcite that allows to find the new integral equations determining a surface current density in the case when the incidentfield is not a plane wave. solutions of these generalized equations allow to find
inflation is a successful paradigm for the physics of the early universe.   it provides primordial perturbations in perfect agreement with the observations, but it requires a greater than planckian axion decay constant, which may not be stable against gravitational corrections in string theory. here   we show that chromo - natural inflation can be achieved by coupling a u(1 ) field coupled to a su(2 ) field with a nonvanishing vacuum expectation value ( vev ) of the vector multiplet of the inflaton to a scalar inflaton via a dilaton - like coupling or by modifying the kinetic term of the axion and slowing down its evolution through particle production as in warm inflation. when this condition is realized, the vector field can be integrated out while, at the same time, leaving its mark on the inflationary dynamics ( an explicit realization of the so called _ gelaton _   mechanism ). in this limit  , chromo-natural inflation is equivalent to a single scalar field using two or more x - ray axions, which are coupled to each other via a yang - miller - mills - like interaction.. the effect of this interaction on the
the correspondence between pierre rmond de montmort and nicolaus bernoulli, a member of the bernouchi family, began in 1703.   the correspondence contains discussions of issues related to the card game le her, waldegrave s problem of the pool, and the game les trennes, as well as problems in algebra, geometry, differential equations and infinite series. among the mathematicians of the era, montmort corresponded with isaac newton, gottfried leibniz, brook taylor and abraham de moivre, in addition to several others. as an aristocrat,   montmort s network included both political and scientific connections. as a talented amateur mathematician, he was generous to his scientific friends ; he sent gifts of cases of wine and champagne to newton and taylor as guests at his chteau de mont Mortons.    the correspondence also contains discussions about problems in probability, including the " problem ofThe pool ", generalized to more than three players, and of the game Le Her, which refers to the decision to switch cards for a player who has a king ( the highest valued card ).
we present a new technique for computing the weak - noise asymptotics of the mean first passage time ( mfpt ) to the barrier in the limit of weak noise for systems without detailed balance, whose dynamics are determined by non - gradient drift fields, or are otherwise time - irreversible.   the method is based on the use of the eyring formula, which is widely used in the context of chemical reactions by eyring, and is readily and quantitatively applicable to systems without'detailed balance '.
we study the low temperature properties of @xmath0 antiferromagnetic heisenberg chains with bond impurities.   we investigate the magnetic structures by calculating the magnetization profile, the spin correlation function, the local susceptibility and the local field susceptibility. in the case of a weak or stronger bond between the bulk bonds,   the impurity bonds cause a localized magnetic structure around the system. in some cases   it is possible to move the position of the bond impurity while in others the position does not change. for the uniform chain where @x Math5 is at the center of the chain, the strength of the interaction between the two impurities depends on the number of spins of the hamiltonian. when an impurity is placed in an open uniform chain, it is found that the right domain and the left domain behave almost independently at modestly low temperatures. according to whether there are even or odd numbers of spins in the domain, the magnetic property of the domain shows very different characteristics. in order to study the force acting between the bonded impurities, we use a monte carlo method which is based on the theory of the dipole - induced local staggered magnetization ( lstm ).
we study the late time power spectrum of gravitational waves in the randall - sundrum brane cosmology, evolving through the radiation - dominated stage after their generation during inflation.   we use the wronskian formulation to obtain the power spectrum and then show our numerical results in sec. for the braneworld cosmological model with a single brane embedded in an anti - de sitter ( ads ) bulk, we find that the amplitude of the kaluza - klein modes increases from ~0.1 to ~2.5 eu in the first few seconds after the generation of the gravitational wave perturbations, and this increase is proportional to the amount of dark radiation generated due to excitation of the " zero mode " and the " kaluchenklein modes " in the second postinflation period. by taking into account the effects of quantum fluctuations in the graviton field, we show that the intensity of the dark radiation can be estimated to be about 1.5  kcal / mol in the early universe and about 0.4  kcal/mol in the late universe.
we develop a maximum - likelihood framework for inferring the best tree topology under ( general ) markov processes.   our approach is based on the widely used expectation - weighted method for estimating the phylogenetic topology of four taxa and is applied to the reconstruction of four - taxon trees, which can be used as input for quartet - based phylogenetic methods. in particular, we consider a general markov model that is locally and globally time nonhomogeneous ( instantaneous substitution rates are not constant on any edge, nor on the whole tree ) and it is neither time - reversible nor stationary. when some symmetries on the transition matrices or on the root distribution are imposed, one obtains the substitution matrices of the corresponding jukes - cantor and kimura ( 2 and 3-parameter ) models among others ( ( *?????*@xmath0 4.2 ), @xcite, see methods section ). by considering this model and its submodels  , we can obtain more general phylogenetic reconstruction methods that are not affected by the presence of long - branch attraction.
the kerr rotating black hole solution displays some remarkable relations to spinning particles.   this changes drastically the usual black hole image since there appear the rotating source in the form of a closed singular ring of the compton radius. in this paper   we consider consequences of the electromagnetic excitations of the kerr circular string and find out an unavoidable appearance of one or two axial half - infinite strings which are topologically coupled to the k errring ring and similar to the dirac monopole string. these strings carry the chiral traveling waves induced by the e.m., fermionic, and relativistic ( and gravitational ) excitations from the k errring ring. for the moving particle the excitations on the axial strings are modulated by de broglie periodicity and therefore they turn out to be the carriers of the traveling electromagnetic waves.
quantum interference is a major mechanism to control quantum dynamics.   if a system exhibiting quantum interference is sensitive to the phase of applied driving fields, then the interference itself can be conveniently controlled by controlling the relative phase of the applied driving field. in this article, we revisit the three - level system in @xmath0 configuration, where the upper state decays spontaneously into the two lower states coupled by a classical driving field, and the two paths interfere, with a relative phase between the two path amplitudes equal to the driving field phase. here  , we derive a set of equations for the two dressed lower states alone, and solve this numerically for different initial field configurations. for coherent fields, which are closest to classical fields,   we find the same results as in the classical case. by analyzing driving fields consisting of a single fock mode, few adjacent number states, or separated fock states, it is possible to find the origin of the quantum interference and to identify the interfering pathways. however, it turns out that it is not the large total width of the photon number distribution which is crucial for the interference, but rather a fixed phase relation ( coherence ) between adjacent fock modes.
the crab nebula is a well - studied object in the sky, in all wavelength regimes.   it has been established as a tev gamma - ray source by the whipple group, using the imaging atmospheric cherenkov technique, and has been studied with many other cherennikov telescopes. here  , we present an investigation of the size of the emission region of the Crab nebula at tev energies using the hegra iact system of imaging atmospheric Cherenkov telescopes ( iacts ). from the observed spectrum,   we show that the effective source size decreases with increasing energy of the radiation, with radio emission extending up to and beyond the filaments visible in the optical, whereas hard x - rays and multi - tev beta - rays are produced primarily in the direct vicinity of the termination shock of the pulsar wind.the results are consistent with a power - law extending from a few 100 gev out to energies of 50 tev and beyond.
the recent detection of the emitted radiation from several exoplanets by the _ spitzer space telescope has spurred numerous theoretical efforts to model their atmospheres and predict their emitted spectra. in this paper  , we describe our estimate of planet - to - star contrast ratio in bands centered at @xmath12.   we then combine these results with our re - analysis of the earlier measurement at@xmath13 @xcite to consider what constraints may be placed on the temperature and chemistry of the planetary atmosphere, and the efficiency with which it redistributes the incident stellar radiation from the day side to the night side. for hd  189733b, a transiting exoplanet at a distance of only 19.3  pc from its host star, we find that the observed contrast ratio is significantly higher than the predicted value, and that the effective temperature of the atmosphere is lower than previously predicted. using a combination of these results and previous observations of the broad band spectrum of h d  209458b in 5 of the above bandpasses, we conclude that the emission of the planets in the region of interest is due to a more intense exchange of light from the sun with the star than expected.
uniform sampling of bipartite, directed or undirected graphs ( without self - loops and multiple edges ) with fixed degree sequence has many applications in network science @xcite.   it has proven difficult to generate truly unbiased samples of graphs with fixeddegree sequence. in this paper   we analyse and further develop a different markov chain approach : the curveball algorithm, which randomises bipartites and directed graphs with self- loops by repeatedly making small changes to the state space of the graph. using this approach, we find that the mixing time of the markov chains is much faster than that of the best known switching model, i.e. the maximum number of possible edge pairs can be reached in a single step. for directed graphs,   our proposed algorithm offers a flexible framework that can be used to randomise several classes of graphs.
the theory of semileptonic ( sl ) @xmath8 decays is a rich and well - studied subject.   the full differential rate in the standard model ( sm ) for these processes has been previously presented by several authors in refs. here  , we extend these results by providing expressions corresponding to complex amplitudes. instead of assuming the relevant helicity amplitudes to be relatively real, as is the current status,   we provide angular terms corresponding to non - zero, complex and independent components. since the basis is orthonormal, this reduces to a simple counting measurement that is model - independent.
we report the discovery of a jupiter - sized planet, xo-5b, that transits the g8v, v=12.1, star gsc 02959 - 00729 ( xo/5 ) with an orbital period, p@xmath7 4 days.   this planet is the fifth hot jupiter transiting planet announced by the xo survey @xcite and is one of the few planets that is inconsistent with general trends based on the currently known sample of transiting j Jupiter - sized planets.
we present the discovery of a new bright, low - mass eclipsing binary system, gj 3236.   the components show high activity levels, as evidenced by h@xmath6 emission lines in the spectra of both stars, and show rotational modulations in the light curves that are synchronized with the binary orbital period of @xmath15.. this system thus has the potential to yield an additional precise test of stellar evolution models for high activity and short orbital periods.
we study the heat conduction of a one - dimensional ( 1d ) chain model in sec.  [   sec : chain ].   we find that the thermal conductivity of the chain is divergent, i.e., it diverges with system size as @xmath7 or@xmath1, depending on the boundary conditions.    the main reason for this is the fact that the temperature gradient is not well - defined and the heat current is not proportional to the temperature gradients. by using mode - coupling theory and molecular dynamics, we show that the divergent exponent of the heat conductivity is related to the power of super ( sub ) diffusion.
the atmospheric neutrino data from the super  kamiokande ( sk ) experiment show evidence for the disappearance of muon ( anti)neutrinos.   the simplest explanation of the data is the existence of @xmath1 oscillations, but several other physical mechanisms have been proposed in the literature as viable explanations. in this work   we consider three of these models : neutrin decay, flavor changing neutral currents ( fcnc ), and violations of the equivalence principle or, equivalently, of lorentz invariance. all these model have the common feature of ` disappearing'muon neutrinos, however the probability depends in different ways on the neutrini energy and path. to discriminate between these models a detailed study of the disappearance probability @x Math2 and of its functional form is needed.. the results show that the present data allow to exclude the three ` exotic'models, at least in their simplest form, as explanations of the atmospheric neut rinos problem.
the behavior of individual cars in traffic flow is controlled by motivated driver behavior, together with some physical boundaries.   the most interesting special case, which covers the majority of all traffic flow situations, is that of single - lane traffic. here, all cars can be ordered according to their position on the road in the car motion direction and the drivers can choose the steady - state velocity ( the optimal velocity ) chosen by drivers as a function of the headway distance between the cars. at each moment of time, a driver changes the speed of her car depending upon the road conditions and the arrangement of the neighboring cars : at the mean speed of traffic flow,   one car moves at a faster speed than the other ; at the same time, the other car travels at a slower speed, depending on the current velocity of the two cars. for this reason, the best model to describe the individual car motion is to take into account only the following - the - leader model, i.e., the interaction between cars and the time update rule. in this paper   we introduce a new approach called the combined model, which takes into account both the effects of the driver behavior and the vehicle configuration.    the combined
@xmath1co @xmath2=21 observations with nanten2 and h data obtained with the parkes 64 m telescope toward hess j1745 - 303 are reported.   the observations show that the observed @x Math1 co @x math2 = 21 line is an extended source in the galactic center ( gc ), which is separated from the central molecular zone ( cmz ) by @xMath10, while it is not clear if this source is connected to the cmz. a molecular cloud ( hereafter mg358.9 - 0.5 )   is located toward the galactic - western edge of the shell - like distribution, which surrounds an extended snr g359.1 - 0-0.5 @xcite near the origin of the @x maths1co # 21 cosmic - ray emission. among the possible associated objects,   we found a strong association of the proposed molecular cloud with the hess source and identified other possible association between the hes source and atomic gas.
the junction condition relating the radial pressure with the heat flux at the boundary of a relativistic radiating star is studied using the lie theory of differential equations.   the main objective of this paper is to generate exact solutions for the equation governing the boundary condition of a conformally flat radiating spacetime by transforming the junction condition equation to an ordinary differential equation for each symmetry in the optimal system and to find solutions invariant under elements of the ideal system.. the results are compared with the results of previous treatments of the junction boundary condition which assume conformal flatness and anisotropy in the pressure due to neutrino flow.
the fractional quantum hall ( fqh ) states are the first non - abelian states expected to be realized experimentally.   the moore - read pfaffian quantum hall state@xcite is the " simplest " non -Abelian generalization of the laughlin state. in this paper  , we use the pattern - of - zeros classification to systematically classify the different possible topological phases that may occur in a multilayer fq h state. by using this classification,   we find that the halperin+/pfaffia+/halperin(+)state is the simplest non - Abelian single - layer state and so one of the first bilayer f qh states to be discovered experimentally.see research article http://www.biomedcentral.com/1741-7007/1471-7006/10/9/8/1
in a fusion reactor, bare solid walls would be exposed to high fluxes of energetic particles, fusion neutrons and heat.   however, they can be protected by a sufficiently thick @xcite liquid metal layer ( lm ) to partly attenuate these fluxes and absorb the heat. in this paper, we present a strategy for controlling the thickness of lm layers by feedback control. using ultrasound-, laser- or electrode - based sensors, we show that local adjustments of the electric current density of the working fluid used, galinstan, can be precisely controlled by local changes in the strength of the electromagnetic forces that push the surface of the lm against the substrate. as a result,   the intensity of the magnetic field can be adjusted locally by adjusting the current density at the same time. due to the magnetized environment  , these adjustments can be performed by an array of electrodes, which are then used to adjust the local effects of electromagnetic forces on the liquid metal instabilities caused by the force fields.see research article .
the su(3 ) skyrme model is a nonlinear field theory having localized solutions, the so - called skyrmions, that are of finite energy and are characterized by a topological charge.   it is an effective theory of low - energy qcd in the limit of a large number of colours, thus it describes baryons in a weakly coupled phase as was initially argued by @xcite. to date   the semiclassical quantization of the model has proven to be successful in describing the phenomenological properties of the baryonic solitons in the low - energies region. here   we show that the quantum mass correction terms to the mass of the Skyrmion that appear in the canonically quantized su(2 ) and su ( 3 ) versions of the models are essential for ensuring the stability of the quantum Solitons of the su(4 ) version of the system. using the bound - state approach to the model  , we find the stable quantum solatons by varying the complete quantum energy functional with the su-(3 ) octet or decuplet quantum numbers and then solving it numerically. even though the wess - zum
the anti - hyperon polarization in baryon fragmentation regions is analyzed by using the quark - diquark cascade model with spin.   we investigate the soft hadronic interactions in the regions of @xmath23gev / c. we analyze hyperon and anti -hyperon polarizations in unpolarized proton - proton and proton- nucleus ( @x Math1 ) and @x math24 collisions, and find that the spin-@xmath25 baryons contains an intrinsic diquarks - antidiquark state with a probability of about 7@xMath0.
the coherent transport properties of graphene nanoconstrictions ( gncs ) with two wide metallic agnrs attached to a narrow metallic one with two vertical zigzag boundaries(zbs ) are studied.   the transmission rate and the local density of states(ldos ) are analyzed using the nearest tight - binding approach and the recursive green s function method. in the first part of the paper, we first discuss the lattice vacancy effects on the transport property of metallic agnr, and then study the coherent transport by breaking the zbs of the gncs one by one. using a one dimensional model for the gnc, we are able to understand the resonant tunneling behaviors of the gnc through the analysis of the transmission rates and the ldos of the two types of gncs based on armchair graphene nanoribbon(agnr).the results show that the conductance spectrum of the semiconducting gnc is affected by the presence of a single vacancy at the edge of the agnr and the gap in the transmission spectrums is related to the appearance of localized zero energy edge states@xcite.    the second part of this paper focuses on the performance limits of gnr
we present a simple method to solve the two - flavor neutrino - plasma oscillation equations in terms of the electron density profile and the corresponding medium properties.   the procedure is restricted to two - flavors of neutrinos, and is applied to the case of exponentially decaying or oscillating electron neutrinoprojects. using the general method, we find that the equations can be solved up to a sign choice for either @xmath22 or@xmath23 by simply substituting the results shown in eq.   (  ) into the mid equality in eq. from the first and the last equations in this work, we get @x Math21 and @xMath22, which are interpreted as the normalized difference between neutriano - plasma flavor populations. instead of prescribing a given plasma density as usual, one can start choosing @x math26, which is interpreted as an expression of the neutrina flavor polarization vector. then, eqs. at the end of the second and third equality in these equations give resp.    the coherences of the two flavor populations with respect to the embedding plasma medium, and finally the corresponding values of the energy associated to the
we present a new method for the analysis of the gauge dependence of nonperturbative solutions of dyson - schwinger ( ds ) equations in qed@xmath6 with four - component fermions, i.e. when gauge bosons ( ` photons') remain massless in spite of interaction.   it is based on the assumption of certain infrared form of two basic propagators as dependent on a couple of unknown parameters and the substitution of these into ds equations to obtain the set of relations for the introduced parameters which are then solved numerically or analytically. by means of this method we show that the obtained results are in general agreement with those obtained in the previous work   @xcite.
gravitational microlensing is a powerful tool to look for extra - solar planets, and as discussed in more detail later, this is the only method sensitive to the search for earth - like planets around normal stars, using ground based observations.   this paper discusses the role of stars as lenses, and the effect of planets as potential lenses. by using the gravitational effect of the planet as a lens,   it is possible to detect planets around nearby stars with a high probability of detection. here  , we discuss the current state of the art in the field, and some preliminary results from the planet collaboration are presented.
the electoral campaign is a period preceding elections where political parties do an organized effort so that their candidates garner supporters.   politicians use different techniques to transmit their messages in the most effective way to their potential voters, such as mass meetings, rallies, husting or media management. understanding and exploiting in a more efficient way the available resources for information flow than your opponent can make the difference. in this article   we introduce a new parameter that measures the ratio of the support in twitter between two candidates, which we call the relative support, and apply it to the 2011 spanish presidential elections, to show how it can be used to indicate and quantify which candidate and in which proportion is getting more benefits from events occurring offline.we further study the dynamical patterns emergent from the twitter mention and retweet networks within the framework of complex networks theory @xcite. by filtering these networks and analyzing the interactions going on between the different political parties, we find that the Twitter mentions and retweets of politicians are highly heterogeneous and there is a high heterogeneity in the distribution of people with similar interests and preferences. using a model based on the heterogeneous preferential attachment formalism@xcite capable of growing political conversations and illustrating it by reprodu
the central few hundred parsecs of the galaxy are dominated by a flat, disk - like distribution of stars, gas, and dust.   the galactic bulge is composed primarily of an old starburst - like population formed early, some 710 gyr ago @xcite. in contrast, the galactic nucleus harbors substantial young and intermediate - age stellar populations. here  , we report deep photometric and spectroscopic observations of 329 late - type giants in the globular crescent ( gc ), complete to 50% at @xmath615.5 mag. for the first time, we include all of the stars in the gc that have been identified by broad - band photometry, including the most luminous giants and supergiants.    our observations show that the majority of the Gc stars formed more than 5 myr ago, though they also find evidence that significant star formation also occurred during the past 100 myr. however, their conclusions are limited by their bright magnitude limit, which samples only short - lived evolutionary stages, for which theoretical models are uncertain.
magnetic reconnection is a fundamental physical process on the sun, and is considered to be the cause of many kinds of solar activities, from drastic eruptions like flares and coronal mass ejections to small - scale events like ellerman bombs and microflares.   although magnetic reconnection has been shown to occur in the upper chromosphere or transition region during solar flares, its observational evidence is still elusive. in this letter  , we report observations of a reconnection scenario in the chromosphere that produces a microflare by investigating the h@xmath2 and 8542 line spectra of the fast imaging solar spectrograph ( fiss ) and the near infrared imaging spectropolarimeter ( niris ) installed at the 1.6 meter new solar telescope ( nst, @xcite ) of big bear solar observatory. for the first time, we observe a bidirectional outflow of hot outflows from the lower chromosphere leading to a go b - class microfl flare in the active region noaa 12146 at 21:04 ut on 2014 august 24. using the data from the two spectroscopic instruments, we show that the outflow was in the direction of the
the description of low - energy meson - baryon interaction in the strange sector is a highly puzzling problem.   the direct application of the effective theory approach @xcite, which was successful in the pion - nucleon sector, i.e., baryonic chiral perturbation theory, is problematic because of the presence of a resonance below the @xmath2 resonance. to overcome this problem,   a multi - channel lippmann - schwinger equation with the interaction described by separable potentials@xcite is proposed.    the effect of the p - wave part of the interaction is included in the model and the solution of the lippman - sch winger equation is derived for such potentials. 	 the results show that the proposed approach is feasible and can be used to study the properties of the resonances generated by the separation of the two modes of interaction.
recent observations of the inner crab nebula using the subarcsecond hubble space telescope ( hst ) and chandra have yielded evidence of dynamic activity in close proximity to the pulsar psr b1951 + 32, with various shocks and ` wisps'evolving in terms of position, morphology and luminosity over timescales of days to weeks, implying local velocities of order 0.7c.   such multiwavelength observations challenge our understanding of these + pulsar / plerion / supernova remnant ( snr ) associations, as the estimated current rate of particle injection derived via nebular x - ray luminosity differs markedly from the historical average rate determined from the radio emitting particles. here   we present a detailed astrometric analysis of the system using archival hst & chandra data, in addition to new ground based optical and ir observations.    the results show that the nebula is a cometary pulsar wind nebula which appears to be confined by a bow shock produced by the high velocity motion of the pulsa, which corresponds to strom s previously defined radio'hot spot '.  also observed is the presence of a synchrotron knot, as
the robustness of quantum control systems has been recognized as a key issue in developing practical quantum technology.   the variable structure control strategy is a widely used design method in classical control theory and industrial applications where one can change the controller structure according to a specified switching logic in order to obtain desired closed - loop properties. in this paper, we present a sliding mode control method for two - level quantum systems to deal with bounded uncertainties in the system hamiltonian.. in particular, we propose two approaches of designing the measurement period for different situations which are dependent on the bound on the uncertainties and the allowed probability of failure.
we investigate the storage and retrieval of a broadband, charged quantum dot - generated single photon with a 1  ns lifetime in an ultracold, dense ensemble of @xmath1rb atoms.   we find that the total efficiency can exceed 28@xmath0 for storage and backwards retrieval of this photon in a density - dependent manner in a system with an on - resonance optical depth of 150  nm. using the gradient ascent approach, we determine the maximum efficiency as well as the optimal control pulse for photon storage. by using a 12  mw control pulse, we show that the best quality quantum memory can be obtained by generating a control pulse from a 12-fold increase in the excited - state hyperfine splitting bandwidth of the quantum dot photon at a distance of 0.5  mv.    the control pulse can be easily generated using a small amount of water and is found to be very efficient for storing a single photon over a long time scale ( up to 3.2  ms ).
we present a new method for the study of spin - dependent azimuthal asymmetries arising in the sidis and drell - yan cross - sections of the nucleon.   the cross - section expression for the lepton off transversely polarized nucleon sidis processes can be written in a model - independent way @xcite@xcite : @xmath1\left ( { { { f_{uu, t } } + \varepsilon { f^{uu, l } } } \right ) \textcolor{0.00,0.07,1.00}{a_{uu}^{\cos { \phi _ h}}}. \nonumber & & \hspace*{-1.4 cm } \times\bigg\ { 1 + \sqrt { 2\vare psilon \left ( {\frac { 2{\phi   h } } ] } \left(1 - { \vacepsilon ^2 } \ right) } \text color[rGBGemini } } = \frac { 1 - \vancepsilon } \ left(1 to \vcepsilon }}
the abundances of carbon ( c ) and oxygen ( o ) in the photospheres of solar - type stars have been estimated to vary widely among galactic disk stars in the solar neighborhood.   recent studies have revised the solar ratio of these two elements downwards from @xmath3 to < 0.5, suggesting that the composition of the host - star photosphere may be more complex than previously thought. here   we review the results of a series of analyses of the spectra of 13c / o ratios obtained from the nasa _ kepler _   mission and the doppler radial velocity surveys of the solar nebula @xcite and discuss the implications of these results for the prediction of the final bulk composition of planets.
we investigate the possibility of simulating the curved spacetimes by photonic fields interacting with a mechanical oscillator operating in the reversed dissipation regime ( rdr ) of optomechanics.   our first proposed system, i.e., a planar optomchanical microcavity, is characterized by an effective kerr - type photon - photon interaction mediated by a movable end mirror. due to the radiation pressure force,   an effective fluid - like behavior for photons emerges which is mediated by the mirror motion. using the hydrodynamic equations for the photonic fluid, we can study the corresponding effective metric for the propagation of fluctuations in the photon fluid. in this manner  , the optomychanical system can be regarded as a quantum simulator for the propagating of the collective excitations of photon fluid in a curved spacetime.
the main contribution of our work is the _ context - specific hammersley - clifford _ theorem, which allows to factorize a distribution by exploiting its independences.   the main result of this work is that it allows to obtain a more sparse representation than that obtained with conditional independences, providing theoretical guarantees. for this, a log - linear model is used as a more fine - grained representation of the markov random fields ( mrfs ) @xcite. by using such models  , it is possible to extend the advantages of the hammersly - cliffords theorem, that is, improvements in time, space and sample complexities.
we study spatiotemporal correlations of the service usage patterns of individual users by analyzing a handset - based dataset.   this dataset was collected from 124 users handsets for over 16 months as a part of the otasizzle project at aalto university, finland. a software installed on handsets collected information about the handset s locations and service usages of various services, including web domain visits, applications, emails, voice calls, and short message services, with the resolution of seconds in time and mobile network base stations spatially. using the context detection method, we identify several contexts that are meaningful to each user by means of the spatiotemsporal trajectories of the users. then, we find correlations between the spatial trajectories and the service use patterns, and discuss their temporal correlations, time - ordering behavior between services, and behavioral overlap network based on the clustering results. among the contexts for each user,   several contexts are found to be meaningful to them by using the contextual detection method applied to the spatio - temporal trajectory of the user, and then we observe the similarity and diversity in temporal patterns of the Service usage patterns. also, we discuss the temporal correlations and time - order behavior between
the optical gravitational lensing experiment ( ogle ) is a long term project with the main goal of searching for dark matter in our galaxy by identifying microlensing events toward the galactic bulge. during the observing seasons 1993, 1994 and 1995   we monitored globular clusters ngc  104=47  tuc and ngc = 5139=@xmath2  cen in a search for variable stars of various types.   most of the monitoring was performed through the johnson @xmath0 filter.. profile photometry was extracted with the help of dophot and the obtained data were deposited at the nasa nss data center. in this paper we present results for 42 variables identified in the five observed fields. all except two are new discoveries and have been assigned names oglegc212 - 255.
the axion is a light neutral pseudoscalar particle yet to be discovered.   it was introduced to solve the strong _ cp _ problem@xcite. in this paper  , we report on the development of an x - ray detector for the axion helioscope made of silicon pin photodiodes operated in a low temperature environment using a superconducting magnet and a low energy threshold and moderately good resolution. by performing a series of axion search experiments with the new instrument, we obtained a limit to the coupling constant of the axions to photons, @xmath5   for @x Math6 and @x math7 for @Xmath7.
the kardar - parisi - zhang ( kpz ) universality class introduced by the stochastic equation   @xcite is one of the most fundamental examples of nonequilibrium interface growth model.   the benchmark of k pz universality classes is the lateral growth that leads to an excess velocity such that the interface envelop moves faster than the rate at which particles are added in the system. here  , we present a detailed analysis of the nature of the intrinsic width of the ballistic deposition ( bd ) model in 2 + 1 dimensions and its relationship to the evolution of the kpZ universalityclass in this model. for the bd model, the surface evolution exhibits strong corrections in the scaling traditionally attributed to an intrinsic width    that hampers the direct observation of the critical exponents of theKpz critical equations in higher dimensions. using simulations of very large systems and very long growth times,   we show that the origin of these corrections lies in the short wavelength fluctuations in the height increments of the interface height along the deposition events. on the other hand, the asymptotic average velocity and the amplitude of the height fluctuations of the
protein interaction networks ( ppi ) have been extensively studied over the past two decades as a record of all metabolic processes and their inter - relations.   however, the complexity of these networks makes them difficult to decipher. in this letter   we show that despite their apparent complexity, it is possible to establish common features of protein networks starting from a few simple principles @xcite. by examining protein interaction networks of 20 different organisms ranging from bacteria and plants to homo sapiens, we find that all biological networks are robust to random attacks, but are less robust to malicious attacks.    our results suggest that evolution has tuned biological networks to be more robust against attacks than statistically comparable, but non - biological, networks. through many generations of attacks,   biological networks have evolved to be better able to cope with the fragility of individual protein function.
we present a simulation of the dynamics of a wave that is traveling through a cell of air and water.   the simulation is based on the volume of fluid method and the vof algorithm, which uses the operator - split method of puckett _ et al.    ( 1997 ).  in the simulation, the atmospheric pressure forcing is used to force the cell to break into four distinct stages : a. atmospheric forcing ; b. potential flow before breaking ; c. breaking which consists of plunging, spilling and splash - up events ; and d. could flow after breaking.  one of the key features of this simulation is the use of a low - pass filter to control the velocity of the wave. as a result  , the rate of potential flow is proportional to the time elapsed from the beginning of the potential flow to the end of the breaking event. for each stage, we find that the maximum potential flow occurs when the cell is completely filled with air, and the lowest potential flow happens when it is fully filled with water. here   we demonstrate the simulation results using a video of a vortex tube breaking.
the ly@xmath0 emission from high - redshift star - forming galaxies is one of the fundamental tools to study the galaxy formation at high redshift.   it is, however, still difficult to understand what the dominant origins of the observed emission are, and how the emitted photons escape from the galaxy. in this study, we used the narrow - band filters to search for the blue- and p cyg - type emission lines from the @xmath9@x Math7 galaxies. using the broad - band filter, we found that the emission - line regions of these galaxies are mostly reprocessed by the neutral hydrogen gas with large bulk motion and show a double - peaked profile possibly dominated by the blue peak due to the combination of the infalling gas motion and line radiation transfer effects. on the other hand, the absorption line is generally blueshifted for typically 200 km s@x math5 indicating that the outflow gas motion is common among the lyman break galaxies. based on the results of the simulations, we propose that the observed blue peak can be explained by the scattering in the simple expanding shell models and the redshifts of the inter - stellar absorption gas around the emission region which are nearly
quantum thermal machines have been proposed as a family of quantum absorption refrigerators, that is, refrigerators in which the external source of work is replaced by a heat bath.   it has been predicted that, with a suitable choice of the machine parameters, such a refrigerator can ideally attain a coefficient of performance ( cop ) reaching the carnot bound @xmath1 for the three - qubit refrigerator object of our study. however, we argue that the central assumption of vanishing mutual interaction between the refrigerator qubits can not be realistically maintained. as long as the interaction is finite,   each bath will exchange energy with the whole three-qubit system, rather than just locally with the single qubit to which it is connected, thus embodying a fundamental source of irreversibility that is expected to arise in all concrete implementations of the refrigerator model. using unstructured bosonic baths and a consistent dissipative qubit - bath interaction  , we show that the cop at maximum power is tightly upper bounded by the temperature difference between the three temperatures between which the refrigerator operates, and give sufficient conditions to saturate this bound in the limit of large temperature difference@xmath5.    secondly, we issue a
type ii supernovae ( sne ) are the end stage of the evolution of massive stars with initial masses on the zero age main sequence greater than 8 @xmath0.   these explosive events deposit a tremendous energy to the surroundings with typical explosion energy of 10@xmath1 ergs per event. in view of this very harsh environment, the detection of molecules in the nebular phase a few months following the explosion of a sn came as a surprise. since then, carbon and silicon monoxide ro - vibrational emission bands have been observed in other type ii sne as well and appear to be the only molecules detected in sn ejecta to date. here   we review the role of the first overtone band of carbon monoxide, co, in the formation of simple diatomic molecules in sn ejecteda and discuss the possible mechanism of this observation.
the first - principle investigations of the proton transport mechanism in the superionic phase m@xmath0h(xo@x math1)@x Math2 ( m = rb, cs, nh@x maths1 ;   x = s, se ) using the linearized augmented plane wave method ( lapw ) implemented in the wien2k package @xcite have been performed.   the results show that the transport of protons in hexagonal ( 001 ) planes is a highly complex process which can be characterized as a transfer of hydrogen ion in the course of the reactions of creation and breaking of hydrogen bonds between the nearest ionic groups xo@Xmath1 and hxo=xmath1. the molecular dynamics studies are based on the density functional theory ( dft ) with the use of the nudged - elastic - band method within the pseudopotential approach implementing in the quantum espresso package @xaite which allows to perform the dynamical relaxation of the atomic surrounding along the steps of the transmembrane proton migration from the high temperature disordered state to the low temperature ordered state at the same time. for each step of the transport,
performance evaluation is a critical step in the design of any optical system, either at microwave or visible / ir wavelengths.   the image quality criteria more commonly used, however, are quite different in these two regions of the electromagnetic spectrum. in this paper we review the main design parameters generally used in evaluating the performance of optical designs at both microwave and visible wavelengths. based on this review   we find a simple relationship between the ( antenna - based ) aperture efficiency and the strehl ratio ; we also show the results of several tests performed to check the validity of this relationship that we carried out using a ray - tracing software, zemax, and a full physical optics software, grasp9.3, applied to three different telescope designs.
in the current paradigm of galaxy formation, it is believed that galaxies are bimodal in color - magnitude plane : red galaxies with very little star formation ( the red sequence ) and blue star forming galaxies that are typically disky ( the blue cloud ).   however, we find that for central dwarf galaxies in the sdss, with @xmath6-band magnitudes between -14.46 and -17.05, just over 1/4 are red. in this paper   we investigate the nature of these red dwarf galaxies by quantifying the spatial distribution of this population of galaxies using the galaxy group catalogue from the universe wide survey of the faintest galaxies ( sdss ) and the galaxy cluster database ( gcdb ). to determine whether or not they can be explained as a population of satellite galaxies that were ejected from larger halos, we use cosmological simulations of dark matter haloes that are close to, but beyond the virial radius of, a more massive neighboring halo, i.e. those that were once subhalos within the virium radii of these more massive progenitors and have subsequently been ejected from their host halos. when we apply the observed
colliding winds in hot star binaries are inherently highly structured.   the question arises how the interaction of winds carrying such inhomogeneties takes place and whether  and to what degree  we have to revise the theory of colliding winds. in this paper  , we attempt to make some first steps towards answering these questions, knowing well, however, that many more have to follow. within the frame of the applied approach   spherical symmetry and sampled line - opacities  small disturbances in one of the flow variables grow very rapidly.the results of owocki and co - workers ( 1998 ) can be interpreted as a form of supersonic turbulence, restricted to spherical symmetry. here   we discuss the physics of the interaction between single wind - inhomogeneities with a stationary wind - wind - interaction zone, before we generalize that picture to the collision of structured winds. finally, we draw some conclusions.
we have measured the cross section for fast neutron production by interaction of high energy muons off carbon, copper and lead nuclei in the cern na55 experiment.   specifically, we investigated the energy spectrum and angular distribution of spallation neutrons produced by the inelastic scattering of 190 gev / c muons on each target, via the time - of - flight method. at 45 ( n1 ), 90 ( n2 ) and 135 ( n3 ) degrees relative to the muon beam, three neutron detectors were placed at 45, 90 and 135 degrees from the target, for a target - detector distance of 2.20 m. the mean cross section of the neutrons was found to be 1.5 cm2/s for the graphite target, 1.0 cm2(n1 ) for the copper target and 1.4 cm2 1 for the lead target. during the two - second beam - on phase,   the cross sections of all three targets were measured at 45 degrees. with an average detector rate of about 20 mhz, the yield of neutrons per phototube per second   was estimated to be about 0.6 j / cm2
we have analyzed anomalous wtb couplings via single top quark production in @xmath2 collision at the cern lhc.   we have used the effective lagrangian approach to study these couplings and we have found that the results are consistent with the standard model ( sm ), but the effects of on - shell top and/or bottom quarks are not well described in the sm. for off - shellTop quarks,   the observed anomalous couplings can be explained in full generality by using the on - mass - shell Lagrangian for the w boson vertex.
we present a legendre invariant metric for the space of equilibrium states of an ideal gas and investigate in detail its geodesics.   the equilibrium space is a riemannian manifold whose geometric properties should be related to the properties of the corresponding thermodynamic system, i.e., the curvature tensor. from the geodesic equations, we show that the corresponding curvature vanishes as a result of the lack of thermodynamic interaction in the case of systems with two thermodynamic degrees of freedom. furthermore, we introduce the concept of _ thermodynamic geodeic_ as those solutions of the differential equations which fulfill the laws of thermodynamics.
observations of occultations of compact radio sources by solar system planets may be interesting for several astronomical and physical applications, such as testing gr   @xcite, improvement of planet orbits and their tie to icrf  @xcite. in this paper   we present the updated list of the forthcoming occultations that may be useful for radio astronomy observations.   the main differences with the previous work are the use of an extended astrometric source list, and computation of event maps to help better planning of observations.
we have previously shown that the dispersion of an off - momentum particle in a thin - lens nanolaser ( nlc ) beam can be minimized by bending the beam by vertically translating already existing nlc quadrupoles.   this is accomplished by precisely aligning all the quads " level" along the equipotential and then raising the vertically defocusing ( d ) quadrupole to steer the beam through the centers of the vertically focusing ( f ) quads. here  , we consider two scenarios : ( 1 ) minimalism, where the main linac is laser straight except for highly localized bends at a few, widely separated locations ; and ( 2 ) eliminating the steering effect by constructing a main linerac that is laser Straight except for a few bend sites.the first scenario proposes that vertical bending of the beam will minimize the generated dispersion produced by the geometry of the nlc quads, while the second scenario suggests that it will maximize it. both scenarios are based on the theoretical calculation of the order of magnitude of dispersion from the electron energy and bend angle produced by each quad over its length as well as the total radiated energy ( per electron per bend ). using the latter scenario,
we develop the concept of phase coexistence in space - time thermodynamics for a two - dimensional ising model below its critical temperature.   we consider the existence of an active state, containing many relaxation events, and an inactive one, where these events are scarce.    the latter is characterised by rare fluctuations in the distribution of observables that measure the quantity of relaxation events within a finite space -Time window, which are dominated by regions in which there are no excitations. to the extent that these rare fluctuations are dynamical analogues of those near phases coexistence, and for bubbles which are large compared with the bulk correlation length of the active state ( e.g., bubbles of the inactive phase ), they are also considered as manifestations of dynamic heterogeneity.
we have detected high - energy ( hi ) 21 cm - line absorption in the warm neutral medium ( wnm ) using the westerbork synthesis radio telescope ( wsrt ).   the absorption was detected toward cygnus a at lsr velocities of 40 km s@xmath1 and 70 km s/s@x Math1, with corresponding spin temperatures of 6000 @xmath0 1700 and 4800 @x math0 1600 k, respectively.. the measured value of the spin temperature is consistent with the range of kinetic temperature ( 5500  8700 k ) for the wnm in the model proposed by wolfire et al. to provide a constrained physical model of the interstellar medium, we have chosen four sources which are strong enough to detect hi absorption ( optical depth @x maths8 0.001 ) in an integration time of @x mathematics8 12 hours ). from these sources,   only one source has been previously identified as being free of cold absorbing clouds. here   we show that the hi absorption can be detected in all directions except for the outermost region of the galaxy where the emission is dominated by the cold gas. on the other hand, the
psr  b105552 is a middle - aged ( 0.5 myr ) energetic pulsar which has been detected as a source of pulsed @xmath0-rays.   it is exceptional in having both an interpulse and wide radio components, with the interp pulse well separated from the main pulse. here   we use new data to re - analyse the polarisation position angle ( pa ) swings of the pulsar s mp and ip and to create a geometry which is fully consistent with retardation and aberrational effects. using the new data, we find that the radio emission occurs on fieldlines which are confined to a polar cap bounded by the last closed field lines which, in a dipole geometry, touch the light cylinder. at the same time   the radio emissions are not confined to the polar cap, but are spread out over a wide range of wavelengths, including the entire spectrum of the high - energy x - ray profile around psr   b10 5552.    the results are consistent with the model proposed by @xcite in their recent study of the geometries of energetic pulsars.
we investigate the rotational equilibria of a wide range of synchronous and asynchronous magnetic mcvs ( mcvs ) using a model of magnetic accretion.   we include 67 synchronous polars and 4 recently discovered systems that may best be described as nearly synchronous intermediate polars in the process of attaining synchronism. for the remaining 22 systems that lie below the'period gap ', we classify them as'conventional intermediate polar'or'ex hya - like'systems with spin to orbital period ratios in the range @xmath17 and@xmath18  hr. we find that these systems occupy a wide variety of parameter space in the spin period versus orbital period plane, which indicates that accretion occurs by a variety of different types of magnetically controlled flow. however, certain regions of the diagram are sparsely populated. in order to understand this distribution we use a model on the basis of magnetic field strength estimates to investigate the rotation of these systems. here   We show that the most of the systems have a true period gap of about 2% or less, and that they are all intermediate polARS in the processes of attainting synchronism and evolving into polars.
ngc6522 is a globular cluster in the milky way s bulge.   @xcite recently reported that it contains a population iii nucleosynthetic signature consistent with the nucleosynthesis predicted for rapidly rotating massive, extremely metal - poor or population iii stars, so - called spinstars. here   we present a re - analysis of the same cluster stars but importantly with a more detailed accounting of blending lines as well as isotopic hyperfine splitting of the @xmath2-process abundance diagnostics. using the giraffe / vlt data from the program 071.b-0617(a ) ( pi = a. renzini ), we show that the observed radial and heliocentric velocities of the cluster stars are not significantly different from those of the corresponding field stars. however, the spectra of the clusters stars show a significant increase in the ratio per resolution element for the three wavelength settings : hr13 ( 612 - 640 nm ), hr14 ( 638.3 - 662.6 nm ) and hr15 ( 679.7 - 696.5 nm ). to account for the differences in the stellar radial velocity between the
anomalous diffusion in the form of lvy flights appears in many physical, chemical, biological, and financial systems.   the presence of anomalous diffusion can be explained as a deviation of real statistics of fluctuations from gaussian law, that it has lead to the generalization of the central limit theorem by lvy and gnedenko   @xcite@xcite. here   we use functional approach to derive the fokker - planck equation, with fractional space derivative, directly from langevin equation with a lvy stable noise source. starting from this equation we find the exact stationary probability distribution ( spd ) of fast diffusion in symmetric smooth monostable potentials for the case of cauchy stable noise.
the three - flavor mixing scheme of neutrinos is the most promising standard model for the structure of the ( known to date ) most fundamental matter in nature.   it is conceivable that the future atmospheric and solar neutrino observations as well as currently planned long baseline experiments will determine four parameters, @xmath4,@xmath5,#6,#7,#8, and #9, to certain accuracies. here   i discuss two key issues, ( 1 ) the sign of @x Math0, and ( 2 ) how to measure leptonic carbon - carbon ( cp ) violating kobayashi - maskawa phase violation.
quantum phase slips ( qpss ) are quantum fluctuations of the order parameter field that give rise to the finite resistivity of nanowires below the mean - field transition temperature.   it has been argued recently that a wire where coherent Qpss take place may be regarded as a new circuit element, the phase - slip junction, which is a dual counterpart of the josephson junction. here   we demonstrate the existence of coherent qpens in homogeneous nanowire wires in the nonlinear regime of high - bias currents. by means of the quantitative study of current - voltage characteristics, we identify thermal phase slips through the temperature dependence of the switching - current standard deviation, which obeys the 2/3 power law predicted by kurkijrvi. at lower temperatures, @xmath5, a clear saturation of @x Math4 is observed ; this behavior is indicative of macroscopic quantum tunneling ( mqt ).. important evidence in favor of qpns is provided by the fact that the mean value of the switched - current keeps increasing with cooling even when the associated dispersion is already saturated. also, we observe a linear scaling of the saturation temperature @x
we investigate the effects of the multiple timescale competition between photothermal and radiation pressure nonlinearities in an optomechanical resonator.   we show that chaotic spiking sequences are the result of canard explosions in a higher - dimensional phase space, in which the system trajectories are rapidly attracted towards the stable branches of a one - dimensional * s*-shaped manifold, where the slow dynamics takes place. by means of a detailed physical model, we identify the mechanims underlying the observed dynamics.
the outage probability of noise limited wireless cellular networks is one of key measurement of the network performance.   this paper provides a general formula for outage probability taking into account a more general model of path loss. in this paper, we model the base station locations as an homogenous poisson point process @xmath0 of intensity and the location of users in the plane as another homogenous function of intensity. to model cellular network cells, voronoi tessellations are frequently used. however, they are based on the assumption that each user is served by the closest base station ( bs ). in real life,   the bs which offers the best signal over noise ratio is not always the closest because of the fading environment. here  , we show that the path loss fading can be viewed as a poisson points process on the real line and we provide a framework to study this kind of network.
we analyze the critical behavior of a class of classical solutions to einstein gravity augmented by the gauss - bonnet ( gb ) term.   we find that in every dimension, @xmath14, a lower bound exists for the mass of the black string, where the dimensionless gb coupling is defined as the coupling constant of the gb term to the space - time dimension of the solution.    we also use improved numerical and expansion methods to investigate black string solutions including the neighborhood of critical points, @Xmath15 and 3, where there are two critical points : the critical radius of the horizon and the critical mass. at large distances from the horizon   the entropy of the system is higher than that of a black hole, which is consistent with the uniform black string being the preferred state if the radius of horizon goes under a critical multiple of the radius on the compactification plane. using a horizon expansion around the event horizon we also find an exact lower bound for the non - uniform black String mass,@xmath6, where it is a product of the critical distance between the critical point and the center of the singularity.
the t2k project  @xcite is a second generation long baseline neutrino oscillation experiment which will use a high intensity off axis neutrinos produced by the jparc 50 gev ( initially 40 gev ) proton beam.   the first phase of the experiment will be the near detector complex ( nd280 @xcite ), which will be built at the distance of 280 m from the target along the line between the average pion decay point and the super - kamiokande detector. in order to achieve the physics goals of the experiments, it is important to provide precise measurements of the neutrini beam properties, neutrinox flux, spectrum and interaction cross sections. for these purposes,   two fine grained scintillator detectors ( fgd s ) with dimensions @xmath9 m@xmath10 will be installed in the ua1 magnet operated with a magnetic field of 0.2 t, a pi - zero detector ( pod ), a tracking detector which includes time projection chambers ( tpc s ) and finegrained scints, an electromagnetic calorimeter ( ecal ), and a side muon range detector ( smrd
we use the self - similar spherical collapse model to compute the outer profiles of dark matter halos in a flat @xmath0cdm universe.   we find that the mass accretion rate and the dimensionless matter density of the universe are the two basic parameters that determine the asymptotic profile of these halos, and that the steepening of the dark matter density profile around the splashback radius is due to the recent accretion of recently accreted dark matter.
the current paradigm for understanding the evolution of the early universe @xcite is the redshifting of quantum fluctuations of the field driving inflation, the inflaton, beyond the hubble radius, leading to an imprint on the background scalar ( density ) and tensor ( gravitational waves ) metric perturbations that subsequently seeds structure formation. in this work   we show that in a multi - field scenario in which the inflationary potential is characterized by a broken symmetry, the quantum fluctuations generated during the slow - roll stage of inflation represent fluctuations in the initial conditions for the dynamics of the infinaton in the subsequent stage, thus implying that the background dynamics after the slow-roll phase has ended will differ in different regions of the universe.   since the background fields are coupled to the other fields into which they decay, the fluctuations produced during theslow - roll phase will affect the subsequent decay process.
the microwave background signature of an open universe is distinct from that of a flat universe.   open universes differ from flat universes in two distinct ways : ( 1 ) the geometry of anopen universe is hyperbolic rather than flat ; and ( 2 ) density fluctuations in anOpen universes stop growing at redshifts much smaller than @xmath7. in this lecture,   i will discuss how these two differences lead to a distinctive microwave background signatures for open - universe models.
the zero - resistance state ( zrs ) of electrons in the presence of microwave radiation is a striking phenomenon observed in experiments on high mobility two - dimensional electron gas ( 2deg ) in presence of a relatively weak magnetic field and microwave radiation.   the most intriguing feature of zrs is their almost periodic structure as a function of the ratio @xmath0 between the microwave frequency@xmath1 and cyclotron frequency @x Math2.. we develop the theoretical approach proposed in @xcite which argues that impurities produce only smooth potential variations inside a bulk of a sample so that zrs at high @x math9 appear from the orbits moving along sharp sample boundaries. here   we show that the dynamics in a vicinity of disk has significant similarities with dynamics of orbits along a sharp edge leading to appearance of z type features in a resistivity dependence on #xmath9.
a new proof of the generalized ray  knight theorem is presented.   it is based on a description of the bijection between height curves and binary trees, and on a simple proof that a certain law on the exploration paths is in bijection with the law of a continuous time binary galton   watson random tree. for the supercritical case,   we renormalize our data and take the weak limit, thus providing a new extension of delmas extension @xcite of the second ray  knights theorem.
braid groups are very important tool for studying links.   many link invariants such as jones polynomial are first constructed via closed braid representative of links, so it is natural to study an application of this interesting structure of braid groups to knot theory. in this paper   we study the application of left - invariant total ordering of a braid group @xmath1 to tie knots using nielsen - thurston s theorem  and we find that braid ordering gives some information about the geometry of its closure which can not be obtained from known invariants of links.
in this article we formulate a theory of carrier dynamics in metals and semiconductors in which disorder is weak, strong spin - orbit interactions are present and a weak slowly - varying electric field is acting.   we focus on the adiabatic particle dynamics and demonstrate their relevance to transport phenomena. for these systems   the wigner function formalism may be simplified by defining a reduced one - particle density operator based on the bloch wave functions. using this formalism, we show that the carrier position is gauge invariant and that the wave - packet formalism captures the physics connected with adi abatic motion and the berry phase, in particular the beryll curvature correction to the wave packet equations of motion.we also discuss the effects of band mixing induced by the electric field on the wave functions and the relationship between the two formalisms.
the cern large hadron collider ( lhc ), a 14 tev @xmath0 collider, is scheduled for completion in 2005.   the next linear collid ( nlc ), an expandable, 0.5 to 1.5 tev@xmath1 linear collider that will begin operation shortly thereafter, will probe the entire parameter space of weak - scale supersymmetry. at susy07  , we will finally know whether weak- and/or strong - scalesupersymmetry is realized in nature. here   i report on some preliminary steps taken in this direction by the supersymmetric working group at the 1996 snowmass workshop @xcite.
experimental evidence for rapid thermalization of the dense matter created in heavy ion collisions at rhic @xcite provided strong motivation for a new look at the non - perturbative structure of the quark gluon plasma ( qgp ).   recently it has been argued that close to the transition from low temperature hadronic matter to the plasma phase of qcd bulk viscosity might play a much more important role than the smallness of the shear viscolysis in the plasma phases. here   we provide evidence for the presence of a contribution to the correlation function of the trace of the energy - momentum tensor that is constant in euclidean time but temperature dependent. using the su(2 ) gauge theory we show that the temperature dependence of this contribution scales like the specific heat and thus dominates the singular behavior of this correlation function in the vicinity of @xmath1, which is the critical point of the second order deconfinement phase transition in the 3-dimensional ising model. by contrast, the parametric dependence observed in the sum rule analysis derived in high temperature perturbation theory and through the spectral representation of this correlator is consistent with the existence of a constant contribution corresponding to
the entanglement entropy of a spin@xmath9 antiferromagnetic heisenberg chain with boundary impurities located at two ends is investigated. by using the method of density - matrix renormalization - group ( dmrg ) @xcite, the entropy of ground state is calculated and the effects of the impurities are analyzed.   the results show that the entropy in the open boundary condition without impurities is much lower than that in the closed boundary condition. for a spin chain consisting of the first adjacent spins of a semi - infinite chain, which is opened by a weak transverse boundary magnetic field impurity, the effect of the boundaries on the entropy is stronger than that of the central bound defect.
lyman-@xmath0  line emission is an increasingly important tool for identifying actively star forming galaxies in the distant universe.   we use the strong rest - frame optical emission lines of [ oiii @xmath9  and h@x math0 @x Math10 to study the kinematics of a sample of lyman_@x maths0  emitting galaxies. using population synthesis modelling, we estimate the dynamical masses of these galaxies based on the observed line widths. using deep archival photometry, we analyze the stellar populations and dust reddening in these galaxies, using the relationship between gas mass surface density and star formation surface density to show that they lie on the same sequence as starburst galaxies. combining these results with the results of velocity dispersion measurements and spectral energy distribution fits  , we explore the mass densities of the sample and the implications for its future evolution.
staggered fermions are gauge - invariant gauge invariant operators that preserve enough chiral symmetry to prevent those operators of our physical interest from mixing with operators of wrong chirality and to protect quark mass from additive renormalization.   they also allow large taste changing quark - gluon interactions, which make the perturbative correction large even at the one loop level. in this work, we have developed a new scheme for the calculation of @xmath3 using improved staggered fermion action and operators using fat links. by comparing the numerical results with the experimental results,   we show that the proposed scheme significantly reduces the size of the matching coefficients for the improved staggered actions and operators.
abstracta transit - like signal was recently detected in the _ kepler  light curve of kic12557548 ( hereafter kic 1255 ), a k5-k7 dwarf star.   the signal is unlike any exoplanetary transit curve previously observed, characterised by a short pre - ingress brightening phase, a sharp ingress and an extended egress, with a period of just 15.7 hr. here   we report high - cadence multi - color observations of this transit using ultracam @xcite on the 4.2 m william herschel telescope. for the first time, we show that the transit signal is caused by a highly irradiated super - mercury, surrounded by an opaque cloud of dust and metal - rich gas constantly replenished by the embedded planet through a thermal parker - type wind feeding a comet - like obscuring tail. at the @xmath14 level  , we found a correlation between the transit depth and the activity of the star, pointing to stellar activity being the primary energy source driving the evaporation.    we also observe flaring events observed in the u band and compare the morphology of individual transits with
the magnetization of the @xmath6-stable neutron star matter, which consists of protons, neutrons, electrons and muons, is investigated using the relativistic mean field ( rmf ) theory.   the results show that the anomalous magnetic moments ( amm ) of all the components of the neutron star subject to the magnetic field are smaller than those of the non - magnetized matter. in the case of the leptons, the amm of these particles is also smaller than that of the other components. for the proton component,   it is shown that the effect of the amms on the magnetization is more pronounced than for the other three components. by comparing the results of the rmf calculations with the experimental results, we conclude that the strong magnetic fields observed in the neutron stars could be due to the formation of a ferromagnetic quark state in the dense matter.
we consider a consensus seeking problem over a quantum hybrid network consisting of a number of nodes each holding a qubit, where projective measurements are applied and the measurement results are exchanged via classical communications.   the problem of optimal path planning for the network with all - to - all classical communications is shown to be a stochastic optimal control problem, whose computation and communication complexities are analyzed. in this paper  , we also develop a distributed pairwise qubit projection ( pqp ) algorithm, where pairs of nodes meet at a given time and respectively perform measurements at their geometric average. using the proposed algorithm, we find that the qubit states are driven to a consensus almost surely along the proposed pqP algorithm.    the expected qubit density operators actually converge to the average of the network s initial values, consistent with the work of @xcite for open quantum networks.. the proposed method is tested on a hybrid quantum network, where the quantum operations are performed locally and then the outcomes of the measurements are exchanged by classical communications, leading to the so - called local - operation classical - communication networks.
background : while the choice of food ingredients and their combinations is dictated by a range of factors such as geography, culture, climate and genetics, the sensory mechanisms of taste ( gustatory ) and smell ( olfactory ) play a dominant role to lock - in ingredients into recipes.   understanding the process of culinary evolution can help bring to the surface, the guiding principles behind the development of the cuisine.objective:to explore the possibility of modeling the evolution of indian regional cuisines to identify the key elements that drive its nature.materials and methods : we have created three models ofIndian cuisine using data from the largest online repository of recipes for indian cuisine tarladalal.com ( november, 2014 )  @xcite where we extracted 2543 recipes and their corresponding ingredients from the database. through these models we have generated a set of 1170 flavor compounds corresponding to 194 ingredients from which we have identified the most authentic ingredients belonging to each of the regionalcuisines.results:the results show that the fitness random model generates a cuisine which is similar to the real world not only in terms of its statistical patterns but also in termsof its flavor profile. when compared with the fitness ranked
a common game is to arrange the dominoes in a row and give a push to the first.   this generates a pleasing wave of falling dominoe. given the game s simplicity, it is perhaps surprising to discover that an exact computation of the speed @xmath0 is quite difficult. in this work   we develop an expression for the speed using the scaling function v = g ( d. )  as a function of the following parameters : height, spacing, and initial configuration. with these conditions,   the problem is solved by assuming a uniform propagation speed and conservation of momentum.
the present paper presents a new version of the stellar evolution code tycho 6.0, which is being developed by the university of arizona astrophysics group as an open - source, community code.   the new version has been equipped with screening effects in the derivation of thermonuclear reaction rates as well as with various new auxiliary programs which can monitor both the evolution of a star and nuclear reaction networks under various conditions. to facilitate versioning and differentiation from the existing version, the version independently evolved and implemented here will be referred to as _ tycho 7.0_ while all relevant improvements and modifications over the previous version will be consistently recorded and published. for the first time   we describe the programs and then its input and output files along with a test - run for a 3 m star and a particular initial composition.
the melting of double - stranded dna ( dsdna ) to two single - strands of dna is a well - studied phenomenon.   however, the effect of bending rigidity on the melting transition is still left out in the newer studies, making comparisons to experiment questionable. here  , we provide a model that accounts for this effect, while leaving out excluded volume effects. using the generalized poland  scheraga model, we show that at high forces of about @xmath0, dna melts into a new state called s - dna, which is composed of locally molten pairs of single strands forming ` bubbles'and alternating segments of native dna. with the exception of the slop of the phase boundary,   the remaining features of the model are left out, and the resulting transfer matrices are truncated in a basis of spherical harmonics. as a result, we obtain force  extension curves and phase diagrams of the melting process, along with the native ( double stranded ) fraction. by fitting the results to the experimental data, we demonstrate that the observed trends are not due to the reentrant character of the stretching force, but rather to the nonlinearity of the dipole
we calculate the equation of state ( eos ) dependent model spectra of the accretion disks around rapidly rotating neutron stars.   these models, when fitted to the observed spectra, can in principle help to constrain eos models and hence to understand the properties of core - matter at the neutron star core. here   we present an analytical function which describes both the relativistic spectra and the newtonian spectra well.
we report on the results from multi - pointing observations of the near - by x - ray bright cluster awm7 with  ( @xcite ) in the pv phase.   the data show that metal abundance is a factor of @xmath4 high at the center, and the distribution of temperature and abundance is highly variable over a scale of 500 kpc.
the non - markovian effect on the decoherence dynamics of open quantum system @xcite is studied.   the main aim of this work is to analyze if and how the coherence present in the initial state can be trapped with a noticeable fraction in the steady state even when the environment is consisted of a vacuum reservoir with trivial structure, e.g., a periodic band gap material or a leaky cavity. by using the recently developed reservoir engineering technique, we show that the non - marking effect can be used to suppress the decay of the quantum bit ( qubit ) in the long - time steady state for the environment with a nontrivial structure. as a result  , it is shown that the transient dynamical process between the qubit and the reservoir is not only the transient one, but also the asymptotical one.    our analysis shows that the physical mechanism behind this dynamical suppression to deco coherent behavior is the formation of a bound state between the Qubit and its reservoir. from the no - decaying character of the bound state,   it is found that the inhibition of the decosherence and the residual coherence trapped in the equilibrium state is due to
the modification of the free space properties of a vector meson in hadronic or nuclear matter is an important problem which has attracted much attention. among the properties of immediate interest are the mass shift and width broadening of the particle in a medium.   many authors have studied these questions for the @xmath0 meson, and also in some cases the@xmath1 meson at zero temperature in equilibrium nuclear matter. here   we use experimental data to construct the amplitude for vector mesons scattering from pions and nucleons in a pion heat bath. using our amplitude the in - medium self - energy of the @Xmath0 and @x Math1   mesons can be calculated at finite temperature and density.. the results are compared with results from the ultra - relativistic quantum molecular dynamics ( urqmd ) model @xcite which has been extensively tested.
parameter inference from limited and noisy data in complex nonlinear models is a common and necessary step among many disciplines in modern science and engineering.   variational bayes, a method that has been mainly applied to particular inference procedures like hidden markov models and graphical models, is a promising tool where the posterior is approximated by simple distributions. here   is introduced a new paradigm from which a proper bayesian estimation for large complex models can be done in the basis of a gibbs sampling for the given model s weights. this makes the procedure of relatively low computation cost and this cost increases slowly as the inference model s dimension grows.the proposed method is based on a recently introduced algorithm for density estimation in stochastic search processes, namely the stationary fokker  planck sampling ( sfp ) strategy @xcite. it is tested on three layered artificial neural networks of increasing size using a classification benchmark problem and two regression problems consisting of real time series with well documented difficulty and experimental interest.
we investigate the ground - state concurrence and the block - block entanglement in a two - legged @xmath0 spin ladder with additional four - spin ring exchange.   the system has a very rich phase diagram with many exotic phases, which can be decomposed in terms of spin operator involving bilinear and bi - quadratic terms, i.e.\end{aligned}\ ). to study the relationship between the phase diagram and the quantum phase transition ( qpt )  , we study the scaling behavior and some extremal point in the block-block entangler at a qpt point. for the first time, we show that the two - site block - blocks are exactly either maximal or minimal at the critical region of the qpt. moreover, the scale behavior and the extremal points in the pairwise scaling behavior around the critical point can be used as markers of qpts.
in 1974, t hooft described the behavior of the large @xmath1 limit of qcd in @x Math0 dimensions @xcite.   he showed that the model confined quarks and was exactly soluable. here   we review the results of einhorn s study of deep inelastic scattering ( dis ) using the same model, but with transverse spin degrees of freedom for the quarks. by extending the spinor degree of freedom to 1 + 3 dimensions  , we were able to recover the callan - gross relation, which was lost when the model was limited to@xmath0 dimensions only. a method of treatment of the confining interaction that removes all singularities from the theory and gives finite dressed quark masses, and the consequence of including transverse degrees offreedom for the spin of the qu atoms is discussed.    we calculate the dressed quink mass, and also study the properties and spectrum of @x math4 bound states, and show that the on - shell scattering matrix must be zero, as required for confined particles. finally, we discuss the consequences of the completness of the bound states.
in the kinematical region of small @xmath3, the gluon is the leading parton driving the behavior of the deep inelastic observables.   the standard qcd evolution gives a powerlike growth for thegluon distribution and related quantities, and this feature leads, in principle, to the unitarity violation at asymptotic energies, requiring a control of the glucosurface in high energies. in the partonic language, in the infinite momentum frame, the small momentum fraction region corresponds to the high parton density domain, which is connected with the black disk limit of the proton target and with the parton recombination phenomenon. these issues can be addressed through a non - linear dynamics beyond the usual dglap formalism. here   we review the current knowledge about the non -linear dynamical regime that plays an important role in the theoretical description of the reactions in the forthcoming experiments rhic and lhc.
we examine the consequences of non - lte corrections to surface gravities ( logg ) and  for logn(be / h ) vs.  ( or be - fe ) diagram for the oldest metal - poor dwarf stars.   we find that for the range of iron - poor objects -3 @xmath2 [ fe)/h = 1.5, non - levenin & idiart ( 1999 ) ( ti99 ) calculations compensate changes in be abundances ( as result of logg corrections ) in the be-fe diagram, recovering the same linear behavior of lte derived abundances.
event shape variables are well suited to testing the basic properties of qcd and for improving our understanding of its dynamics.   they are collinear and infrared safe observables, which means that one can safely compute them in perturbation theory and use the predictions as a means of extracting the strong coupling @xmath1. besides this, they are also well suited for determinations of other parameters of the theory such as constraining the quark and gluon colour factors as well as the qcd beta function. here   we review the current state of knowledge about the physics of event shape distributions and compare them to experimental data.
pks 2155@xmath0304 is a blazar that is highly variable across the entire electromagnetic ( em ) spectrum.   it is the brightest blazar in the uv to @xmath10ray bands in the southern hemisphere and is one of the most commonly observed blazars for simultaneous multi - wavelength observations. here  , we study the long term optical / uv and x - ray flux variations in this source using the archival xmm / newton data of pks 2 155@x math0304. by fitting the spectral energy distributions ( seds ) of the blazar with a log - parabolic model, we find that the low energy sed hump in the high synchrotron peak band peaks in the mev  tev gamma - ray bands rather than the sub - mm to soft x-ray bands. from the normalization of the model normalization parameters,   the light scattering from the relativistic electrons in the super massive black hole at the center of the jet is more intense in the soft x - rays than in the hard x - ramsay bands. on the other hand, the high energy sed humps in the intermediate and high syn
condon domain phase in beryllium is observed by dc field and standard ac method with various modulation levels, low frequencies and magnetic field ramp rates at high magnetic field and low temperature.   the effect of strongly correlated dipole - mediated van der waals voltage ( dhva ) oscillations on the fermi surface of berylliium is explained by the anomalously low curvature of the cigar - like part of the fermani surface near the extreme cross - sections ( waist and hips ) of the first and second zone monster ( coronet ) and the third zone cigar, which are characterized by a very small curvature. for proper calculation of amplitude of the dhva oscillations and constructing the phase diagrams, the correct topology of ferm i surface has to be taken into account.. the model based on approximation of relevant fermic surface sheets by cylinder predicts the existence of inhomogeneous phase at the values of external magnetic field contradicting to the experimental data that show the disappearance of condon domain structure at higher values of applied magnetic field.
supersymmetric theories possess remarkable properties on the quantum level.   these properties are provided by non - renormalization theorems according to which supersymmetry theories have a much better ultraviolet behavior than the non - supersymmetric ones. in this paper   we show that it is possible to construct a regularization which preserves the supers asymmetry and which will be convenient for practical computations of supergraphs using the superspace structure of superpropagators, containing the delta - functions of anticommuting variables that allow to shrink the loops into dots in @xmath8 space, the superfield background field method for supersymmetrical gauge theories, and an assumption about existence of a special regularization manifestly preserving the supersuumetry.
the study of recurrent epidemics has a long history, and many models, both deterministic and stochastic, have been considered.   several recent models have considered epidemics on a network that changes structure dynamically according to rules that do not depend on the nodes epidemic status. in contrast to the models of a static network or models with externally applied changes in structure, a new class of models based on endemic sis populations on an adaptive network has been recently introduced. here, the new parameter is one that describes the rewiring rate of the network, which is controlled by the fraction of susceptible ( s)-infective ( i ) links. for appropriate choices of parameters,   bistability between the disease free equilibrium and endemic state has been observed. in this paper, we introduce a recovered, immune class and consider this slight generalization of the sis model on an Adaptive network. using monte carlo simulations and mean field models for epidemic evolution on evolving networks, we examine the structure of the system and the dynamics of the fluctuations of the epidemic.
we report hysteresis loops of the switching mechanisms of nel caps in flux - closure fe(110 ) dots under a magnetic field applied transverse to the central domain wall  ( dw, 2d objects ) of the dot.   the switches are triggered by the application of a strong out - of - plane magnetic field along the inner magnetization direction of the bloch wall, and the final remanent state is selected by the sign of the applied field@xcite. using micromagnetic simulations we show that the shape of the dots can strongly modify these switching mechanisms, and thereby induce an asymmetry when the shape itself is asymmetric.
the reionization era is expected to end at the redshift interval @xmath7 or so, when the first sources of uv radiation turn on, and reionize the universe.   detection of this epoch would be a major cosmological milestone. in this letter   we present evidence which suggests that we are already probing the trailing end of this era, at ~@xmath12 or so. using the high s / n, keck spectroscopy of the quasar sdss 10440125 discovered by @xcite, we show that the observed absorption due to neutral hydrogen at @x Math9 is not as thick as previously predicted. however, it is much thinner than the observed emission from the same region of the universe due to the ly@x math11 forest at @Xmath26 , and shows a second discontinuity at @ xmath27 , due to an apparent increase in the energy of the ionization forest. taken together, these data support a picture of an extended and patchy reionisation era, ending at @xxmath15.
the dynamical correlation functions of the transverse susceptibility in a single - impurity kondo model   @xcite are calculated using the real - time renormalization group method in frequency space.   the calculations are based on the integration of the scattering states of the equilibrium system @xcite with a landauer - bttiker formalism, which allows the application of a finite voltage in the usual manner. for all combinations of the parameters voltage, temperature, and magnetic field, the coefficients of the correlation functions   are found to be linear in the range of 0.1 to 1.0.    the results are compared with the results obtained using the flow - equation method, which is used to study the longitudinal correlation function as well as the magnetization and t - matrix in an impurity model in and out of equilibrium.
the mode - coupling theory ( mct ) has been used to test the validity of the @xmath0-relaxation in molecular liquids.   the results of this work show that the theory properly describes some essential features of structural relaxation even for some complicated molecular liquids, such as the influence of the cages formed by the neighbors of the molecule on the reorientational motion as it is caused by steric hindrance. in this paper, correlation functions and susceptibility spectra   shall be discussed, which deal with the glassy dynamics of the orientational degrees of freedom of nonspherical molecules immersed in a simple liquid.the results are obtained as solutions of the equations of motion derived previously @xcite for the dynamics of a linear probe molecule immersed in an equilibrated hard - sphere system, and the solute, a van - der - waals liquid propylene carbonate ( pc ). at four temperatures,   two sets of data are presented : one set of data deals with the response for angular - momentum index@xmath1=1 ; it was obtained by dielectric - loss spectroscopy ; and the other set shows the effect of the density fluctuations of the solvent on
broad absorption line ( bal ) quasars are powerful type i active galactic nuclei that contain gas that is moving at extreme velocities, apparent from their broad emission lines ( bels ) and in blueshifted absorption troughs.   these spectral features arise from compact gas flows close to the accretion disk, apparent by high ionization lines and size scales from reverberation mapping @xcite. despite the importance of these processes, the connection between compact and large - scale outflows is not understood. here   we use microlensing to study the shape of the broad emission line region ( belr ) of the gravitationally lensed quasar h1413 + 117 ( the cloverleaf ; magain et al., 1988 ), which is a lobal quasar with both virial and multi - component flows. using differential magnifications of lensed images of the quasar, we show that the belr of this quasar has a unique shape that is consistent with the nature of its outflow, inflow, and orbital motion : it is a highly elliptical region, with a broad absorption profile that is dominated by low - ionization absorption in aliii and high - ion
excitonic molecules - or biexcitons - are known and well studied since several decades in conventional semiconductors.   their formation due to the coupling of a pair of excitons and their photophysics properties have been well established both theoretically and experimentally @xcite. in organic compounds,   the interest for excitonic bound states is rather new since the main studies started about five or six years ago. here  , we propose a model for studying excitonal strings in organic charge transfer solids ( ct ). by comparison between theoretical calculations on small clusters and experimental results of differential transmission spectroscopies, we show that the intensity of the optical one exciton - biexiciton transition may decrease when the binding energy of the bieXiciton increases ; moreover, this intensity is shown to be less important than the one of the two exciton transitions and, even, is supposed to be independent of the system size for sufficiently large binding energies.
we examine the post - collapse evolution of five models of stellar core collapse based on two @xmath2 progenitors taken from stellar evolution calculations.   we vary the angular momentum profile and the magnetic field strength in the progenitor star and perform axisymmetric simulations including special - relativistic magnetohydrodynamics and two - moment neutrino transport. at lower densities,   the models differ only in their mass - loss rate, whose values translate to total stellar masses of @x Math8 and @x math9 at collapse.    the results show that the collapse of the cores of stars with low metallicity is likely to result in the formation of a proto - neutron star ( pns ) rather than a black hole ( bh ), while the latter outcome is probably inevitable if no supernova ( sn ) occurs at all. among stars with higher masses, however, the final outcome appears to be more likely to be dominated by bh formation with or without sn explosion.
human visual system has a strong prior knowledge about physical sizes of objects in the real world and can immediately retrieve size information as it recognizes objects.   we postulate that this is mainly due to the lack of a comprehensive resource that can provide information about object sizes. in this paper, we introduce a method to automatically provide such information by representing and inferring object sizes and their relations. to be comprehensive, our method does not rely on explicit human supervision and only uses web data.we use size graph to represent both absolute size information ( from textual web data ) and relative ones ( from visual web data).we show that our method can establish inferences about the relative size of ` sofa'and ` tree'through a set of intermediate relations between ` sofa'-`cat'and'cat'-`tree '. for each pair of objects,   the results show that the size of the sofa'is smaller than that of the'tree'based on the sum of the intermediate relations obtained from the two sets of pairs of objects.graphical abstract
phylogenetic trees are fundamental tools for understanding evolution.   they can be compared by direct visualization, aided by methods such as tanglegrams and software such as densitree, but this does not lend itself to detailed comparison of large groups of trees. here   we introduce a new metric for comparing phylogenetic trees that captures both tree structure and branch lengths. using this metric  , we show how it enables visualization of tree space and detection of islands, and provides a new suite of methods for selecting summary trees.
the theory for the dynamics of electron electric fields at a positive ion in a semiclassical electron gas is studied.   the main new feature studied here is the dependence of structure and dynamics on charge number, with the relevant dimensionless parameters being the charge number of the ion, the electron - electron coupling constant, and the de broglie wavelength relative to the interelectron distance. by using a variational method,   this dependence is shown to be independent of the density and temperature of the plasma and of the electron charge density. as a result, the electronic field autocorrelation function becomes nonlinear in the presence of the external ion potential, and can be solved numerically in a similar way to the boltzmann - poisson equation for the holtzmann integral equations for an impurity in a one component plasma.
we have developed a photon counting method for monitoring the gain change of a photomultiplier in front of a pulsed led light source.   the method is based on the principle of photon counting and consists of injecting a very small portion of the led light output to a monitor photon detector. by measuring the number of photons per pulse detected by the monitor detector,   we can monitor the change in the lead light output every time it exceeds some prescribed level set between the pedestal and the single photoelectron peak. here  , we describe the results of studies on the monitor system and its monitor light monitor system.
the very small array ( vsa ) is a 14-element interferometric telescope designed to image faint structures in the cosmic microwave background ( cmb ) on degree and sub - degree angular scales.   it has been routinely observing the cmb since september 2000 using two different array configurations ; the first used a compact configuration with a maximum baseline ( antenna separation ) of 1.2  m, while the second used a more extended configuration with an antenna separation of 2.5  m. here   we describe two experiments, one currently operating, one under construction, which are designed to provide complementary observations of primary and secondary cmb anisotropies over the multipole range @xmath1 to@xmath2.
the x - ray afterglow of the celestial gamma - ray burst ( grb )970228 was observed by the  satellite in the 0.12.4  kev energy band.   the source was detected in the error box given by the wide field camera ( wfc ) for the grb and in the same wavelength band by the narrow field instruments ( nfi ) on board the  spacecraft. during the observation,   eight sources were detected at @xmath103@xmath2 level in the energy range. of them, one source, rx j050146 + 1146.9, was found in the 3@x Math0 radius error circle given by both the  wfc and the nfi for grb970228. here   we report on results of that observation and its consequences.
the upper mass limit for c / o white dwarfs ( wds ) is still subject to some debate, since it is the aftermath of the evolution of a star with initial mass slightly lower than m@xmath4, the lowest mass for star that succeeds in igniting carbon burning before the asymptotic giant branch ( agb ).   the theory of stellar evolution predicts that an isolated single star with mass lower than about 0.5 m @xmath0, the exact value depending on the chemical composition, do not ignite the helium - burning and die as wds with an helium rich core. in this paper   we show the results of detailed evolutionary computations performed with a full henyey code able to follow consistently the evolution from the initial pre - main sequence to the final cooling phase of wds.
instabilities in plastic flow have been an object of attention for a long time in metallurgical literature.   the conceptually simplest form of this manifests when the material is subjected to a creep test wherein a force is applied and the response in the form of elongation of the material, which under normal conditions, is a smooth strain - time curve, is observed. however, under certain metallurgic conditions, one sees steps on creep curve suggesting a form of instability. here  , we discuss the origin of this phenomenon as a result of a hopf bifurcation resulting from nonlinear interactions between three different types of dislocations.
the existence of a glueball state has not been confirmed experimentally, but its existence is an unavoidable and yet uncannily prediction of qcd.   glueball states may have different lorentz structures in general, such as a scalar, a pseudoscalar or even a tensor with either normal or exotic assignment. the prediction for the glueball masses is, however, a difficult task. here   we show that the lowest lying @xmath12 state for a pure pseudosCalmar glueball can be as light as@xmath24 gev @xcite when the effects of mixing effects and related data for the transition matrix elements of anomalous axial - vector current between vacuum and the three states are taken into account. by using the chiral lagrangian technique, we find that the quenched lattice qcd calculation of the semi - inclusive @x Math10 meson decay into scalar and pseudos calmodular glueballs gives a result of @xMath10 = 1.6 to 2 gev ( p < 0.05 ).    the results support the hypothesis that the gluonic penguin induces the production of glueballs from the
the study of the quark - gluon plasma at ultrarelativistic energies is a very active field of theoretical research.   we present results from numerical simulations of quantum chromodynamics discretized on a lattice by the fastsum collaboration at the lhc, where the experiments alice, atlas and cms are collecting and analyzing data from the collisions of lead nuclei at 500 mev ( approximately @xmath2 k ) well above the temperature of the crossover from ordinary matter to the plasma of quarks and gluons. in particular, we focus on the effects of sequential suppression of quarkonia, which occurs at, or above, the crossover to a chirally symmetric, deconfined phase. for the lightest quarks,   the suppression is due to the restoration of chiral symmetry, but for the heavier quarks it is not immediate : the short - range component of the potential, which is responsible for their binding, and hence the fundamental bound states, might well survive in the plasma, while the excited states dissolve. since bottomonium production is much less prone to regeneration effects, and as such is a more promising observable for the spectral analysis of
theoretical studies of electronic structure of high - energy - density plasmas are of great interest for the understanding of radiative transfer and equation of state ( eos ) and for the simulation of laser - driven experiments.   the purpose of the work presented in @xcite was to propose a new approach to photo - absorption calculations using the superconfiguration method, which includes relaxation effects and allows inclusion of configuration interaction between relativistic sub - configurations of a non - relativistically configuration @xmath0. the model presented here is close to an average - atom model, but constitutes an attempt to include better ( less averaged ) atomic physics. for each configuration,   bound electrons are treated quantum mechanically and free electrons within the thomas - fermi approximation ( hybrid model ). once their electronic structure has been calculated, superconfigurations of the same charge can be grouped into ions. at this stage, the plasma can be considered as an ensemble of ions, containing bound electrons, and immersed in a free - electron gas. by taking screening effects into account, it is shown that, provided that ions of different charges have different volumes, the electronic pressure, calculated together with ionic volumes in a self
the infrared imaging surveyor ( @xmath11 ) is a next generation infrared satellite that will be launched in the beginning of 2003.   one of the most important tasks of the project is to obtain a huge sample of the far - infrared ( fir ) spectrum of actively star - forming galaxies from the universe at redshift < 5.5 m by using a deep survey of the lockman hole region with a flux limit of 45 mjy at 175@xmath0 m, and to estimate the surface density of the fis sources brighter than 150 mj y at 175 @x Math0 m. for this purpose, we have developed a new model of the origin of the visible light emission lines in the near-/mid - infrared camera ( irc ) and a fir scanner ( fis ) on board the infrared imaging surveysor. here   we review the current status of the model and discuss the implications of the results obtained from the irc and fis surveys.
the dynamical evolution of globular clusters has long been the subject of many theoretical studies, including a number of recent papers utilizing state of the art simulations.   these studies find that mass loss due to two body relaxation and the resulting evaporation is the primary mechanism for the destruction of globules. in this paper  , we present results from new, very deep hst images of m87 that achieve these goals with a high degree of accuracy and reliability. using the wfpc2 as part of a 30 orbit program, we have imaged the center of the galaxy with a total of 1040s exposures in the f814w filter, with a single matching 400s exposure in each of the f606w filter. during each orbit,   four exposures totalling 1040’s were taken in one of the filters, and average images were created from the final full data set by stacking the images, after they had been sinc - interpolated to a common origin. at the faint end of the observed gclf, we found large numbers of low luminosity globular cluster features. however, for the milky way, where finding lower luminosity clusters is not as difficult, the small
we extend the results of @xcite about the existence of a massgap for the model with nearest - neighbours, gaussian interactions, in the presence of an arbitrarily weak pinning potential.   we show that this holds for a large class of finite - range non - gaussian interaction models, and that it does not follow from perturbation around the gaussian case. as a byproduct of our technique  , we also obtain an improved version of a result of@xcite proving the existenceof a mass gap for the proposed model with near - neighbours using a square - well potential.
in the present paper we study the difference between attractors in the random boolean network ( rbn ) and the complex network with scale - free topology ( sfrbn ), focusing on the so - called frozen nodes of attractors.   we find that the attractor length is much wider in the Sfrbn than in the rbn, and the attracter length has a longer period than that in the Rbn. this is directly related to the complexity of the network topology, which is very important for the stability of living cells.
this paper presents a first attempt to describe the particularity of considered processes, to give a review of existing models prediction and, at the end, we will offer the field - theoretical formalism for hadron inelastic processes.   using thermodynamical terminology, we wish investigate the production and properties of comparatively ` cold'multi - hadron ( mostly of @xmath12-mesons ) state. from the very beginning   that we have only a qualitative scenario of such states which may be produced and the review of the corresponding why s may be considered as the main purpose of this paper.the results are presented in the form of quantitative proof, formulation of pure theoretical methods etc.
the zen puzzle garden ( zpg ) is a one - player puzzle game involving a buddhist monk raking a sand garden.   the objective of the game is to move a _ monk _ character around the garden, causing him to completely rake the available surface. in this paper   we describe the genetic algorithm ( ga ) for the zpg, and compare its performance with a  base - line ", search - tree - based method. using experimental results  , we show that the ga can be used to solve the problem successfully, with no significant differences between the two methods being found.
in shear flows such as plane couette flow, the discontinuous nature of the transition to turbulence allows the spatial coexistence of laminar and turbulent flow.   the spot stage corresponds to the expansion in two directions of turbulence, triggered by a strong enough local perturbation of the laminationar flow. at reynolds numbers above and below @xmath3,   turbulence can only exist in the band regime, and the large scale flow around the spot is restricted to the oblique band regime. here  , we study the effect of an unsteady large - scale flow on the advection of the rolls characterised by spanwise vorticity in the spot growth regime of plane Couette flow. using a numerical procedure based on the incompressible navier   stokes equations, we show that the instability of the streaks & vortices flow is caused by a secondary kelvin  helmholtz stability of the streamwise velocity, which leads to a departure from the linear regime of the plane couettes. this instability is then studied quantitatively using procedures that will be studied systematically in a future article.
we study the stability of rotating thin - shell wormholes ( rtsws ) in @xmath1dimensions.   we observe that the off - diagonal components of the extrinsic curvature tensor at the throat vanish in case we assume counterrotating components of shells at the neck and the gas pressures from the upper and lower shells cancel each other to modify the equation of state to the extend that it becomes equivalent to a static case. for this reason we choose a simple surface energy - momentum tensor and study its stability condition. by assuming a velocity dependent perturbation of the linear gas equations of state at the junction, we find that the tsws are more stable than those constructed from the black hole solution in which the mass and angular momentum of the baados - teitelboim - zanelli black hole are the same.
the identification of cellular automata ( ca ) models that mimic real - world phenomena remains an open research issue.   the existing methods for ca identification are either designed for a particular class of ca, or their experimental evaluation was limited to the case of synthetic data. in this paper  , we propose a novel approach to identify ca models based on the rough sets theory. according to the proposed approach,   input data describing observed states of cells are represented in form of a decision table and neighborhood is detected by using algorithms for reducts calculation. after that, a rule - learning method is applied to induce a set of decision rules that define the evolution of ca. as a proof of concept, several approaches to identify deterministic and probabilistic ca models for synthetic as well as real - life data sets have been proposed. among them, the first approach uses genetic algorithms to extract update rule and neighborhood from spatio - temporal patterns produced in cellular automaton evolution ; the second approach uses non - genetic techniques to learn rules for different classes of ca ; and the third approach uses parameter estimation methods to select neighborhood size and update rule from the field of system identification. at present, there are no available algorithms for identifying ca
deep - brain stimulation ( dbs ) is a highly effective technique for treatment of patients with parkinson s disease.   the effects of dbs in networks of bursting neurons have been investigated when dbs is implemented through an harmonic external current and a delayed feedback signal. here   we present a reductionist model of the response of a neuronal network to an external perturbation like dbs, which is based on the presence of a single burst of action potentials followed by a quiescent interburst period. as a proof of principle  , we show that the model can be extended to include a large number of neurons in a reasonable amount of time. at the same time, the model is reduced to a minimal one in which only the initial burst of spikes is required to trigger the bursting phase, and the interval between the two bursts is short enough to allow for the detection of the bursting synchronization. using the proposed model, we find that the effect of dc stimulation on the bursting dynamics of neurons is more pronounced in the neocortical layer than in the basal ganglia.
we present the design and experimental proof of principle for a low - threshold optical coherence tomography ( opo ) source that generates broadband, continuous, steady - state oscillations.   we exploit the special properties of two - photon excitation with broadband down - converted light to cause loss only to narrowband oscillations and not to broadband oscillations in the opo cavity. since such two- photon excitations are induced in a pulse - like manner, they can be coherently controlled by tailoring the level of dispersion at different locations within the Opo cavity, leading to a situation where narrow band oscillations, which are insensitive to dispersion, suffer two - photons loss but broadband oscillated oscillations do not.see research article http://www.biomedcentral.com/1471-7007/9/8/5
damped ly@xmath8 absorption ( dla ) systems are observed in the spectrum of high - redshift quasars.   they are thought to be progenitors of normal disk galaxies @xcite, but it is possible that they represent still merging, gas - rich protogalactic clumps, rather than already formed disks. here   we review the literature on dla systems, and discuss the current state of knowledge about them.
waves often form on growing icicles that are covered with a thin layer of flowing water ( see fig.1)@xcite. for many of these patterns,   the wavelength has a gaussian distribution centered at approximately 8 mm ; however, despite their common occurrence, there is no quantitative explanation for this wavelength distribution.   here we show that the wavelength distribution of the waves is related to the growth of the icicle and the flow of fluid along the ice. in the study of crystal growth, such a surface instability is usually explained by mullins - sekerka theory ( hereafter abbreviated as ms ) which is based on two observations : laplace instability and gibbs - thomson effect. in this paper  , we analyze the effects of these two effects on the wave patterns observed on icicles using laminar flow with two interfaces ( ice - melt and melt - air ). because the water layers on an icicle are too thin to produce a laplace destabilization, we neglect the fluid instabilities that require turbulence because there should be no turbulence in these water films @xmath0 thick and the speed of the flow is about 2 - 4cm / s and the interface is lamin
low mass x  ray binaries ( lmxbs ) containing a neutron star ( ns ) are known to contain a black hole candidate ( bhc ).   the accretion properties of these systems can be studied through the timing and spectral properties of the x - ray emission, i.e., the colour  colour diagram ( cd ) and power density spectra ( pds ). in this review   we describe the characteristics of the timing features of the atoll source 4u  160852 ( e.g., @xmath4u1652 ), which is a low mass ns lmxb with a high luminosity ( 0.51.0 of eddington luminosity ) and a low luminosity track ( < 0.010.5 ). as the source moves from the extreme island state ( eis ) to the hard island states ( is ), the cd softens and the pds increase while the x  rays intensity increases. on the other hand, the qpos and broad - band variability components vary monotonically as the sources move along the track. here   they are shown to be related to the position of the source in the cd.
@xmath1  eridani ( hd 29248, @xmath2, b2 iii ) is arguably the asteroseismically best studied @x math0  cephei star.   the star was observed during the second brite - constellation campaign directed towards the field of orion in the region of the sun and the earth. here   we report the results of photoelectric time - series measurements in support of brite that were organized to coincide temporally with ground - based photometric observations of the star. using a combination of near - ultraviolet and time - resolved photometry, we show that the star s pulsation modes are distinct from those of the other @x Math1   cep stars : the latter contain a dominant radial mode that immediately constrains the stellar mean density, while the former contain a triplet of dipole modes. by fitting the observed pulsation spectrum with theoretical models, we find that the two lowest - frequency @x maths3 multiplets correspond to mixed modes, with different contributions from the gravity and pressure mode cavities, which makes the seismic information from them largely independent and complementary.    furthermore, we observe a single quadrupole mode
strongly correlated fermionic systems, responsible for relevant many - body phenomena such as high - temperature superconductivity, the fractional quantum hall effect or metal - insulator transitions, represent one of the most important theoretical challenges in condensed matter physics.   accurate numerical simulations are essential in order to gain further insight into the physics of strongly correlated systems. among the simplest possible models of interacting fermions in a 2d lattice is the hubbard model,@xcite, which is believed to be one of its keys to understanding the theoretical riddle of high - temperatures superconductor properties. while quantum monte carlo ( qmc ) techniques are very powerful in simulating bosonic systems, they suffer from the so - called negative sign problem in the case of fermion and frustrated models. here   we present a new approach to study strongly correlated fermannian systems in a2d lattices, based on using a tensor network ansatz as ground state variational ansatz. with the use of the multi - scale entanglement renormalization ansatz,   @xcite it is now possible to study interactions between fermium antiferromagnets in 2d
the electric power grid plays a crucial role for the daily life in modern societies.   the continuous availability of electric power is of key importance for daily chores. yet, electric power delivery disruptions do occur, causing huge economical and societal cost. among other critical infrastructures, the electric power distribution grid is one of the most vulnerable to disturbances and external forces because of its radial - like structure, which makes it more vulnerable to disruption by external forces.    this paper models an electrical power distributiongrid as a ( directed ) graph in which the nodes represent the electrical and physical assets in the system, while the edges model the logical information about connections between these assets. from a topological point of view, the distribution grid robustness is related to the ability of an asset to be connected to sources ( for supply availability ) from a _ topological _ point of View. using complex networks theory,   this paper shows that the distribution Grid robustness can be assessed by considering the network topology of the distributed grid as a function of the number of nodes in the grid, and the level of redundancy in the network structure. based on the results of the analysis of the u.s. energy information administration ( eia )
we carried out dense observations on bl lacertae ( bl lac ) using a 60/90 cm2 telescope.   we observed the flux variation of this object on both internight and intranight timescales for more than two nights in august 1997 at night with a time lag of about 1.5 hours between the light curves in bands _   b_ and _ i_ during the long 1997 outburst. to investigate the details of the physical processes and geometric conditions based on the brightness and spectral variability, we analyzed the data from four campaigns of the whole earth blazar telescope ( webt ) collaboration by analyzing the intranights optical variability ( inov ), the timesc scales of rising and decaying processes, and the time lags between different optical bands. among the four campaigns,   the results showed that the source was never found to be stable during the entire campaign. however, the source showed a marked trend to become bluer when brighter on the timescale ranging from 30 minutes up to 3.4 hours.    our results suggest that the variability of bl lac has two components, long term ( a few - day timescale ) " mildly - chromatic " variations and strong bl
the three - quark potential is one of the most important fundamental quantities in the hadron physics, because it is directly responsible to the baryon properties and is the key quantity to clarify the quark confinement in baryons.   we perform the first systematic study of the ground - state 3q potential @xmath0 and the excited - state 2q potential@xmath1 using su(3 ) lattice qcd   @xcite. for more than 300 different patterns of the spatially - fixed 3q systems, we perform a thorough calculation for the ground- and 1q potentials in lattice Qcd with @x Math0 at @xMath4 and @x math5 at @Xmath6 at the quenched level. from the results  , we find the universality of the string tension as @x maths11 and the one - gluon - exchange result as ~12.5fm in the maximally - abelian projected qcd ; the gluonic excitation energy is found to be about 1gev.
the rayleigh  taylor ( rt ) instability of a viscoelastic immiscible fluid is studied in the framework of the oldroyd - b model.   the effect of polymer additives on the mixing process is studied by means of a phase - field approach, which is based on injecting polymers into the fluid and studying on both analytical and numerical ground how the stability of the resulting vis coelastic fluid is modified. from the results of the linear analysis of the rt instability we find that the addition of polymers enhances the perturbation growth - rate of the mixed fluid while the effects of the polymer additives are more pronounced in the early stage of its evolution. to verify the results we use direct numerical simulations of the original field equations.
in this review, we discuss the spectrum of a cosmic - ray synchrotron ( snr ) with a low shock acceleration ( @xcite ) and a high compression ratio ( @xmath0 ).   we show that the spectra of this snr are steeper than those of other snrs at frequencies lower than 1 ghz. in the case of shocks with sufficiently low mach number ( less than around ten ), steeper spectra (@xmath6 ) are generally expected. on the other hand,   only few old snrs would be expected to have such weak shocks ( @Xmath5 ). by taking into account the effect of non - linear effects of particle pressure on the shock acceleration, we find that the observed spectra are more consistent with the results of test - particle diffusive shock acceleration theory.
the model - independent benchmark for optimal cooling of a symmetric low - dissipation carnot refrigerator, derived by curzon and ahlborn in 1975, is a useful design guideline for energy conversion systems, as it reliably benchmarks the optimal operation of a large class of heat engines.   we analyze the coefficient of performance ( cop ) at maximum cooling rate for endoreversible quantum refrigerators, generally modelled as _ tricycles _, and find that the details of the system - bath interaction mechanism place a tight upper bound on the cooling performance, which automatically precludes the derivation of any model - dependent benchmarks. here  , we look into the paradigmatic case of a three - level compression refrigerator operating between two different levels of a compression support, where the cooling rate is determined by the temperature of the water bath running between the two levels.. the results show that the optimum cooling rate can be found to be obtained only at the highest possible temperature, and that this is not the case for the other two levels of the support.
vector mesons are among the most commonly studied final state observables in lepton - nucleon scattering experiments.   they are produced in a variety of ways depending on the virtuality of the incoming photon and can be identified by tagging on a large rapidity gap around the outgoing proton direction or by requiring the vector meson to have the same energy as the incoming proton. here   we show that the elastic production of vector mesons is due to a two gluon exchange with a @xmath5 pair in the photon wave function, which results in the formation of the color singlet model   @xcite. for both elastic and inelastic production  , we estimate the expected statistical errors of a measurement at a polarized hera collider with an integrated luminosity of 1000  pb@xmath6, based on the measured unpolarized cross sections.
the indian centre for space physics is developing si - pin detectors and also collaborating with other national and international organizations to fly this simple tool in near future.   the instruments that we plan to fabricate is simple and is solely dedicated to observing only half a dozen black holes ( unless, of course, some more exciting transient black holes divert its attention in its lifetime ).. the payloads are restricted to be about 20 kilograms each.    each cspob will be a 640 @xmath0 si - pins photo - diode based array of detectors which is sensitive in the @x math1 kev range. 	 the data in 256 energy channels will be stored every 100 sec and thus time resolved spectra would be obtained and time lags / leads in keplerian and sub - keplerians components, light curve variations of intriguing objects such as grs 1915 + 105 etc.,there would be two all sky proportional counters ( aspcs ). it will revolve with the satellite and scan the sky for new outbursts. at the end of the mission,   it will have a pair of cspobs which will be able to observe a single celestial body other
brown dwarfs are self - gravitating objects with physical and atmospheric properties intermediate between stars and planets.   the evolution of their spectra spans the spectral classes m, l, t, and y, with transitions demarcated by the appearance and disappearance of absorption lines and bands as molecules form and condense out of their atmospheres at different temperatures and pressures. despite having a basic understanding of their evolution,   brown dwarf formation remains an open question. in principle, these formation mechanisms should leave traces on the statistical properties of brown dwarfs, including the occurrence of multiple systems and distributions of their separation, relative masses and eccentricity. here   we review the current state of knowledge about the formation of brown dwarf binary systems.
we report the measurements of pressure and volume of a gas of spherical particles excited by a vibrating piston and undergoing inelastic collisions. at constant external driving,   the pressure passes through a maximum for a critical number of particles before decreasing for large @xmath0.   when the density of the medium is increased, the gaslike state is no longer stable but displays the formation of a dense cluster bouncing like a nearly solid body. from measurements of secs. 35, we show that the dependence of the granular temperature on the piston velocity, i.e., the mean kinetic energy per particle, is of the form@xmath3, where the rate of particle number is proportional to the piston speed.    this paper is devoted to the study of the low - density situation, where clustering does not occur.
the spitzer archival infrared extragalactic survey ( safires ) is an offshoot of the @xmath0 enhanced imaging products ( seip ) project, which produces reliable, consistent data products for the mid- and far - infrared ( fir ) regimes @xcite.   the safires sample consists of nearly two thousand fields spanning almost two hundred square degrees of sky, including 1132 distinct regions with data in either the 70  or 160  far - ir bands from the nasa / ipac infrared science archive ( irsa ). using the entire cryogenic @x Math1 sample results in unequaled depth of coverage in many well - studied fields, along with a robust source list containing as many as fifty million sources across an area of over 1,500 square degrees. to ensure high reliability, safires source lists include no fields near the galactic disk ; these observations comprised more than half of the area observed by@xmath1, but the practical drawbacks of galactic contamination would inhibit the ability to maintain the level of reliability desired in the safire s products. due to the ways in which the savers image processing scripts reduce the artifacts within each image s background, the final safires data products
we consider the generalized chaplygin gas ( gcg ) as a source of dark matter and dark energy which are interacting.   we construct the model by splitting the total density into dark energy and dark matter components, by means of our assumption. in this way  , we find a dark energy equation of state for dark energy that crosses the phantom divide @xmath3 in recent epoch. its associated density smoothly decays with the expansion of the universe ( thus, phantom - like ). at the end of this section, we show that the model has a scaling solution.
the tanami ( * * t**racking * * a**ctive galactic * * n**uclei with * * austral * * m**illiarcsecond * * i**nterferometry ) program ( @xcite ) provides parsec scale resolution monitoring of extragalactic gamma - ray sources south of @xmath0 degrees declination at dual frequency ( 8.4 and 22ghz ) by making milliarcsecond resolution very long baseline interferometry ( vlbi ) observations with the australian long baseline array ( lba ) and associated telescopes in australia, antarctica, chile and south africa.   the program has produced one of the highest resolution images of an active galactic nuclei ( agn ) jet ever made using naturally weighted images of pks1454@xmath5354 ( @x math6 ), a flat - spectrum radio quasar from centaurus a, which is the closest known radio galaxy to the sun at 3.4 mpc. here   we outline some early results from the tanami program.
we study the radio properties of background quasars at different impact parameters from the mgii host galaxies responsible for the enhanced rotation measure ( rm ).   we obtained images of the fields of 28 radio quasARS with strong mgii absorption lines selected from the sample of  @xcite. in order to identify the mg2 + host galaxies  , we place the galaxies in the quasar field on a color - color diagram and compare them with the theoretical locii of galaxies of different types computed from spectral energy distributions from@xcite as a function of redshift. applying recent results from the study of mgii systems @xmathite, this suggests that the ubiquitous winds in high redshift galaxies @xaite are highly magnetized. furthermore, this finding provides support to the idea that magnetized outflows help remove small scale helicity from galactic disks  .
in this article, we review the use of d  branes to construct perturbative string backgrounds.   we focus on the type iib theory, which is the simplest example of an orientifold, and discuss how to realise it as a model of a superstring theory with spacetime gauge symmetry. in the next section  , we will discuss the advantages of using d branes to study string theory beyond perturbation theory.
the exponential growth in the volume of astronomical data being generated from ever larger format imaging detectors continues to drive up the data handling costs of both large and small telescope projects.   making effective use of the available image compression technologies is an important component in dealing with these data processing costs. in a previous contribution (   * hereafter, paper i ) we demonstrated that the maximum possible lossless compression ratio for integer format astronomical images is determined by the amount of noise in the background pixels ( i.e., the " sky " in the image ). in this current article   we extend the previous analysis of integer images to study compression techniques for astronomical images in floating - point format. in the cases we are mainly concerned with here, these images originally had integer pixel values, but were converted into 32-bit ieee floating -point format during the calibration processing ( e.g., bias subtraction, flat - fielding, absolute flux calibration, etc. ) and were then compressed using a lossless data compression algorithm based on the rice algorithm @xcite which has a small @xmath3 value of about 1.2 bits per pixel. as a result  , we find that the best combination of speed and
the recent release of the fermi - lat @xcite data on the sum of electrons and positrons from the pamela satellite and the atic experiment has been interpreted in terms of indirect signatures of dark matter annihilation ( or decay ).   we compute confidence regions of the parameters needed to fit the data, and show examples of the remarkably high quality fits obtained by some of the best - fit models. for the arkani - hamed et al. model,   the measured distribution seems to favour direct dark matter annihilation to @xmath0, with very little of @x Math1 or @x math2, thus pointing to an unusual underlying particle physics model. however, if the annihilation is first into low - mass states which subsequently decay into leptons, both the absence of@xmath2 and the occurrence of @Xmath0 can be naturally explained, e.g.  if the intermediate particle is scalar or pseudoscalar by helicity arguments.
the @xmath0  orionis star cluster is a well - known brown dwarf and planetary - mass object population in the constellation of orion.   it contains a large number of stars and brown dwarfs, and is an excellent laboratory to study the evolution of discs and angular momenta. here   we present a detailed analysis of the data from the 2mass and denis catalogues in a circular area of radius 30arcmin contred on the fourth brightest star in the orion belt, @x math0  ori. using the mayrit catalogue, we show that the distribution of the stellar and substellar populations in the cluster is very similar to that of the entire cluster, and that the distributions of the two catalogues are highly similar in terms of the initial mass function slope of the mass function, the frequency of discs, and the degree of radial concentration. by contrast, the density of the brown dwarf population is much lower than expected from the densities of the existing catalogues, and there is a significant difference in the ratio of stars per mass interval ( p<0.05 ). this observation is supported by the presence of a strong correlation between the two databases for the first time,
the gravitational bending of light by other astronomical objects has been observed at many times.   the gravitational lensing has been well established as one of the powerful tools in astronomy and cosmology. since the pioneering work by darwin @xcite, on the other hand, the strong deflection limit has attracted a lot of interests, mainly because we expect that the recent progress in astronomical instruments will soon enable us to detect such strongdeflection phenomena.. therefore, the main purpose of the present paper is to extend the earlier work @xmathite, especially in order to examine finite - distance corrections in the strong Deflection limit. for this purpose, we consider a static and spherically symmetric ( sss ) spacetime with a wormhole solution with a throat and a black hole. using the gauss - bonnet theorem, we derive a lens equation for the light deflection in the sss spacetime where the source and receiver are located at an asymptotic region. from this equation,   we obtain the effect parameter of the light ray, which is defined as the difference between the two states of the wormhole and the black hole ; the impact parameter is obtained by rearranging the orbit equation
a common problem that arises when developing a model of a biological or mechanical system is that some of its parameters are unknown.   this is especially important when those parameters have special meaning but can not be directly measured. in this paper   we investigate the identifiability problem of viscoelastic models represented by an arbitrarily complex spring - dashpot network and show in a remarkably simple way how to verify whether the studied model is ( locally or globally ) structurally identifiable. in case it is unidentifiable, our method provides an explanation why this is the case and how to reformulate the problem. using the results of this paper, we introduce a new method for establishing the type of identifyability of a system of ordinary differential equations, which allows not only to check but also to construct an arbitrary complex _ identifiable   spring - Dashpot network. as a particular motivation for this work comes from cardiovascular modeling, although the results can be applied to any vis coelastic modeling approach.
we consider the search for time - dependent backgrounds for string theory in asymptotically locally flat / ads spacetimes.   we find three bubble solutions in the four dimensional case, all time- and space - dependent : two of them are obtained from analytic continuation of taub - nut - ads spacetime and the last one is inspired from the first two bubble solutions. using the multiple analytic continuations of these spacetime solutions, we find a new static bubble - type spacetime that is a nut - charged generalization of the ads soliton, as well as an interesting new time - independent solution : it is asymPTotically ads, yet the bubble evolution is milne - like throughout.see research article http://www.biomedcentral.com/1471-2148/7/9/8/6/5
the main innovation of this paper lies in the study on consensus of compound - order ( fractional - order and integer - order ) distributed multi - agent systems with different time delays.   the proposed coordination algorithms are based on caputo fractional operator, which is more practical than riemann - liouville ( r - l ) fractional operators because r-l fractional Operator has initial value problems.    the proposed algorithm is based on the combination of caputo integral and caputo derivative to model the system dynamics and analyze the stability of the proposed Coordination algorithms. by means of the simulation results,   it is shown that the proposed method can be applied to the coordination control of multicomponent - order multi - player systems with communication delays.
the far - infrared ( fir ) and radio luminosity correlation between the star formation rate ( sfr ) and the cosmic ray population in quiescent and star - forming disk galaxies suggests that the energy imparted to cosmic rays by supernovae is entirely expended through observable emission within the starburst region.   we use monte carlo simulations to study how cosmic rays sample the mean density of an interstellar medium ( ism ) with properties similar to that of the prototypical starburst galaxy m82. using a combination of co and x - ray measurements, we find that the ism consists of a hot, diffuse medium in which dense, warm, ionized gas and dense, cold, molecular clouds are found. for the majority of the time,   the galactic wind is strong enough to advect the molecular clouds, and the magnetic field lines along which they propagate intersect a sufficiently large number of molecular clouds to allow the cosmic rays to effectively enter the molecular cloud. however, as the galaxy undergoes radiative, collisional, and advective losses, the density of the molecularclouds becomes more compact, and it is necessary to increase the wind speed so that the particles can be efficiently injected into the molecular
we present self - consistent dynamical models of circumstellar dust shells calculated with selected laboratory amorphous carbon data.   based on these models we have performed radiative transfer calculations for pure ammorphous carbon and in some cases also including silicon carbide ( sic ) dust. the effects of the model structure and the spectra of the grains on the extinction efficiency can be evaluated. to evaluate the expected spectral dependence of extinction for a given grain model ( i.e.  assumed composition and size distribution )  , we have used the rayleigh approximation for spherical particles which is valid when the grains are small compared to the wavelength, @xmath16 and in the limit of zero phase shift in the particle. using the mie theory, we find that the observed extinction efficiency for the most common type of carbon grains in the envelopes of pulsating stars is about 1.5 times higher than that for the other types of grains. by applying these results to the experimental data,   we have found that the absorption properties of the two - dimensional grains are not significantly different.
genetic relatedness test ( grt ) is a popular test offered by many " direct to consumer " ( dtc ) companies, and is used to identify whether or not a pair of individuals are closely related.   the standard approach to relative identification is to detect the identity - by - descent ( ibd ) segments between the individuals, and further identify the degree of relatedness via the amount of shared ibd segments. in this paper  , we focus on a new privacy - friendly grt algorithm that can operate without accessing genetic data in the clear and violating individuals privacy.. the algorithm is based on a two - party secure computation protocol involving a trusted cloud server with access to an online database consisting of a number of individuals genetic data and a relatedness testing service ( client ) with its own genetic information.    the server encrypts each haplotype in its database using the same encryption algorithm, " subtracts " client s encryption by the encrypted haplotype, and then returns the results to the client. for each individual, the server identifies the quantity of shared positions in the shared positions by calculating the number of 0 s decrypted sequences. as a proof of concept,   we show that the
ultraluminous x - ray sources ( ulxs ) are a new class of non - nuclear black hole ( bh ) candidates, with apparent luminosities well above the eddington limit for galactic stellar mass bhs.   they are 10100 times more luminous than galactic bhbs, and their maximum radiative luminosity is about 10 times higher than that of neutron stars. in this review,   we discuss the current state of knowledge about the nature of these sources, focusing on their spectral and timing properties, and comparing them with other classes of accreting bhs, such as superluminous bhs and intermediate mass black holes.
massive open online courses ( moocs ) are a new model for teaching physics education.   the first edx physics mooc, 8.02x- electricity and magnetism, is a 16-week online course offered through edx in spring of 2013. using self - reported demographics, performance metrics generated by the instructor dashboard, and limited click - stream data stored in tracking - logs, we explore the diversity of the student population through analysis of log - in activity and retention from enrollment to the final exam. as a way of exploring   how diversity affects course outcomes, we analyze retention and performance on exams in the context of the different demographic groups. over the course of the course,   around 43,758 participants enrolled, with approximately one - third of these participants from around the world. while the majority of participants were female, about half of the participants were male, and most were currently employed in the field of engineering or computer science at a university outside of the usa. among those who did not take the course  , there was a significant increase in the percentage of students who were older than 25 years old, had a higher level of education, and were more likely to be from a developing country
inflation is a successful theory of early universe and structure formation.   it is based on a scalar field minimally coupled to gravity with a potential flat enough to support an extended period of inflation. despite its observational successes   there is no deep theoretical understanding of inflation and the nature of the inflation field. here   we generalize the results in @xcite to the case where the mobile stacks of branes are moving ultra relativistically as in dbi inflation. as in@xcite,   the stack closer to the tip is annihilated by the background anti - branes resulting in particles creation during inflation while the second stage of inflation is driven by the remaining stack.we study the curvature perturbations and match them to the matching conditions using a set up that takes into account the existence of coincident branes inside the throat. for the set up we consider two stacks containing @xmath1 and @x Math2 coincident Branes.    we find that the first stack is faster than the second stack so it is annihilationated during inflation transferring its energy into closed strings modes. at the bottom of the throat the secondstage of inflation begins when the first one is annihilized by the
the age of ngc6791, the oldest galactic open cluster known to date at 6.5 - 9 gyr, is estimated using a synthetic horizontal branch ( hb ) model based on canonical stellar models.   the model is based on the arbitrarily chosen chemical composition of the cluster, i.e., @xmath1 and @xmath2. for the synthetic hb, we have assumed a gaussian mass dispersion parameter @x math6, and a reimers mass loss parameter @Xmath7. in order to reproduce the observed color - magnitude diagram ( cmd ),   we have added some random scatter in both @x Math8 and @ xmath9.    the model reproduces, in accordance with the first parameter phenomenon, the prominent red clump seen in the data, but it lacks hot stars. by comparing the observed cmd with the model, we find that the age of this cluster is approximately 10 gyr.
we have extended the classification of surface brightness profiles introduced by @xcite and aladro et al.   ( 2013 ) to include the so called truncation of the stellar population at the edge of the disk, which is a well - known feature of the exponential disk. in order to address the origin of the different types   we have introduced an interpretative subclassification scheme for our profiles.see research article http://www.biomedcentral.com/1471-2148/1058-7007/9/8/6/5.
the nature of the compact object in the x - ray binary has been established.   monitoring observations with the wide field cameras ( wfcs ) on _ bepposax _ revealed the source to be a regular source of type ix - ray bursts which are explained as thermonuclear runaway processes on the hard surface of a neutron star. in the present paper  , we study data taken with the same instrumentation half a year before that and the primary purpose of this study is to accurately analyze the flux of the persistent emission as well as that of two @xmath5150  s long x-ray bursts. also, we studied the variability of the 2 to 10 kev emission.. the results show that the flux measurements after its 1989 discovery are fairly constant at a level of approximately @x math3  in 2 to10 kev.    the continuous emission can be explained by a stable accretion of matter on the neutron star which fuels regularly ignited thermon nuclear explosions that give rise to x - rays.
optical parametric oscillators are one of the most interesting and well characterized devices in nonlinear quantum optics.   novel discoveries made with them include demonstrations of large amounts of squeezing, significant quantum intensity correlations@xcite, and a quadrature correlation measurement that provided the first experimental demonstration @xcite of the original epr paradox. in the present paper, we focus on the optimum below - threshold squeezing results, which determine the limits to squeezing obtained near the critical point, where nonlinear corrections start to dominate. in a companion paper  , we consider the related question of critical fluctuations at threshold.
this paper is devoted to the survival analysis of a system subject to competing failure modes within an external stressing environment.   the external environment is assumed to stress the system at random and isolated times according to a random shock model, where the occurrence of shocks is classically modelled through a non - homogeneous poisson process and where each shock may result in the system immediate failure through a bernoulli trial, independent of the system intrinsic behaviour. apart from shocks, the system suffers from competing soft and sudden failures, where soft failures refer to the reaching of some given threshold for the degradation level, and sudden fails to accidental failures, characterized by a failure rate.the present paper considers several kinds of dependence between the three competing failure mode : at each non fatal shock, the increase of deterioration and failure rate is simultaneous. at each traumatic shock, either because the shock is fatal, or because the deterioration is suddenly increased beyond the threshold level, there is some possible dependence between soft and traumatic failures. at all other shocks,   there is no apparent dependence between these two types of failure modes.the results of the present paper are compared with those of @xcite, which consider only one type of failure mode.
genome size evolution is a process that is thought to be driven by three factors : mutation rate, population size, and biases in patterns of insertions and deletions ( indels ).   we have used the avida artificial life platform to investigate the impact of these factors on the evolution of genome size in a large number of eukaryotic species. using whole - genome sequencing data, we show that genome size does not correlate with organismal complexity, but rather positively correlates with the number of protein - coding genes in the genomes of the organisms studied.. this suggests that larger genome size is a prerequisite for gaining new genes that could lead to phenotypic innovation.
we derive the wigner function of a two - mode quantum state of the electromagnetic field generated by an optical parametric oscillator ( opo ) using a truncated wigneder equation.   this expression is valid in all regions of the opo operation regimes, that is, below, and above the operation threshold, where the validity of both the linear approximation and the perturbation theory break down. to illustrate the reliability of the distribution we obtain, we compare the results obtained with this distribution with those obtained by numerical simulations using the positive p - representation of the density operator without any approximations.
we present a new model of gauss - bonnet gravity in which the spacetime curvature of extra dimensional space is given by lovelock polynomial @xcite and the metric and gravitational field remain finite and regular everywhere.   the key question is how to bring this desirable feature of gaussian gravity down to four dimension where it makes no contribution?   we discuss three different classical motivations for higher dimension for gravity : ( 1 ) higher dimension of action for gravitation, ( 2 ) reciprocity between matter and curvature, and ( 3 ) black hole singularity.
the tevatron proton antiproton ( @xmath0 ) collider at fermilab was shut down on september 30th, 2011.   the top quark, the heaviest fundamental particle ever known, was discovered at the tevilton in 1995. since then  , intensive studies continue to be performed at the two general purpose detectors at the Tevatron, cdf and d0, to gain a better understanding of the production mechanisms and properties of that particle. with the start of operations of the large hadron collider ( lhc ) at cern in 2010,   a top - quark factory has opened, where top - antitop quark pairs (@xmath1 ) are currently produced at cross sections a factor of about twenty higher than at the tesvatron. in this article, i offer a brief review of the history of the teavatron and of the topQuark, an overview of the current status of the understanding of its production mechanisms, and a perspective of what measurements are still important to complete in top-quark physics at thetevatron in view of the onset of the lhC - era.
the hawking radiation in the minkowski spacetime is derived from a vacuum in a static schwarzschild spacetime.   the vacuum in the original paper by unruh @xcite is often referred to as the hartle - hawking vacuum, which is calculated from analytic functions across the exterior spacetime of a black hole and the interior spacetime wedges of a white hole. in the present paper   we explore another possibility of vacuum that spans across the interior and exterior spacetimes of ablack hole, which we will call the r - f vacuum. using the tunneling effect, we find that the temperature of the radiation from the r-f vacuum is twice as large as that from the h artle - haretle -hawking vacuum. this discrepancy can be explained by the difference of vacua from which the radiation comes from.
the primordial cosmic microwave background ( cmb ) was generated when photons first decoupled from the baryonic fluid when the universe was only 400,000 years old.   the vast majority of these photons travel unperturbed to the present day, and features of their angular power spectrum such as acoustic peaks and the damping tail @xcite record valuable information about cosmological parameters. in addition to the importance of learning about the large - scale structure itself, reconstruction of the weak - lensing potential generated by structure is essential to constraining tensor perturbations. here  , we consider a third source of noise that is neglected in previous studies : the filter of the temperature - squared map in fourier space which acts as an unbiased estimator for the lensed potential in the approximation that a correlation between two given temperature modes is induced only by the single lensing mode whose wavevector is the sum of that of the two temperature modes. in actuality,   any combination of two or more lensing modes whose wavevectors sum to this total induce correlations between the two temperatures. using this new estimation method, we show that the filter can be used to reconstruct the non - gaussian correlations in the
diffractive scattering through strong interactions without any large momentum transfer has historically been described in terms of the exchange of a pomeron, a virtual hadron - like object with vacuum quantum numbers.   the discovery of such hard processes in diffractive events at the ua8 experiment @xcite opened the possibility to examine these processes at the level of quarks and gluons in the modern framework of qcd. here   we review the theoretical descriptions of diffractive deep inelastic scattering ( ddis ) data from the electron - proton collider hera @xmathite as a product of an effective pomeran flux factor from regge phenomenology and deep in elastic scattering on the pomerone having parametrised parton density functions ( pdfs ). by introducing a single new parameter, introduced to give the probability for exchange a soft colour octet gluon between any pair of partons, we show that the model gives an essentially correct description of ddis at hera@xmath8 scattering as well as diffractive event at the tevatron having jets or quarkonia @xcites or gauge bosons. using the full event simulation, we also show that this model is
the purpose of the present study is to devise a better operational criteria for the selection of isolated galaxies using sdss dr7 supplemented by bright galaxies from various catalogs.   we calculate the virial radius of a galaxy, @xmath5, and use it with the local background density to select galaxies that have no companion within 2 mpc. in this study  , we show that the results of our study are consistent with those of previous studies where the effects of the nearest neighbor become dominant when a target galaxy is located within the virion radius of its nearest neighbor.
we examine the x - ray properties of the cooling flows in a sample of 30 clusters of galaxies known to exhibit strong gravitational lensing effects. using asca spectra and   rosat high resolution imager ( hri ) data, we present independent determinations of the mass deposition rates in the cooled flows and measure the column densities of intrinsic x -ray absorbing material associated with these systems.   we show that the cooling flow model provides a consistent description of the imaging and spectral data and that the observed masses of intrinsic X - ray absorbing material are in reasonable agreement with the masses expected to have been accumulated by the Cooling flows over their lifetimes.
the lattice boltzmann equation ( lbe ) is a powerful tool for studying complex fluid flows, particularly those involving irregular and/or changing geometry.   the lbe approach to multiphase and multicomponent fluids has been advanced using different strategies to capture the thermodynamic interactions which give rise to surface tension between the phases. in this work,   a number of these approaches are combined and extended to address a new problem : that of colloidal particles in a binary solvent. first, a binary fluid lbe following @xcite is adopted in which the equilibrium distributions are cast in a different, and more intuitive form ; this leads to several improvements in the behaviour of fluid - only problems. as one important advantage of the lb approach is the relative ease with which solid - fluid boundary conditions are included, it is useful to retain lb in both the momentum and thermodynamic sectors of the liquid lattice. here  , we demonstrate the application of this approach to the binary fluid problem using a series of simple test problems for the fluid only, and including a single particle.
abstractthe kinematical data for a well - observed galaxy have been used to construct a model that reproduces the observed velocity dispersion profile.   the model is assumed to be axisymmetric, and the data are used to infer the unique dependence of the mean square velocity on position over the image of the galaxy. here  , we show that this assumption is not the case, and that the observed data do not imply anything definite about the observed stellar system. in particular, we find that the two - integral distribution function @xmath2 can not be found to be consistent with the model if one assumes both isotropy in the meridional plane as well as an ad hoc form for the potential, which is usually represented via some ad hoc parametrization. by contrast, when one assumes that the distribution of stellar velocities is everywhere isotropic, the predicted profile is almost certainly different from the observed profile.
the information flow arising from interactions among stocks in a financial market is a crucial research topic for our understanding of the pricing mechanism.   however, there have not been many studies that have dealt with the factors that affect the existence of significant information flow among stocks from the perspective of the overall market. in this study, we evaluated the effects of market factors on the information flow between stocks in terms of two perspectives - namely, information value and changes in market status. using the @xmath0 links among all of the stocks traded on the market, we can determine whether the information flows among stocks are a mutual exchange of information, a one - way information transfer, or an absence of information flow. based on the results of the analysis, we found that the information value of the market factors varies in accordance with market status, and particularly increases during times of market crises. furthermore, the size of the largest eigenvalue increases during market crises as well as during periods of increased efficiency among stocks. taken together, these results suggest that the relationship between market factors and information flow may be influenced by the degree of efficientity among stocks, and that it is important to investigate the influence of different efficiencies among stocks on the existence and magnitude of information
the bulk spectral function of the bulk channel correlation function in a holographic model of a strongly coupled quantum field theory is studied using the ads / cft holographic correspondence.   the temperature dependent part of the spectral function is found to obey the sum rule for the integral of the integral, corresponding to uniform dilatation or isotropic expansion, which is trivial in a conformal theory such as @xmath1 susy ym. however, nontrivial sum rules in quantum field theories ( such as qcd ) do exist and have been the subject of recent studies. here  , we show that the bulk spectral functions of the quantum field - theory operators are constrained by the sum rules for the high frequency tail of their integral in the form of the l.h.s. of the sum - rule - dplus in the context of qcd, where the coupling is the quark - gluon plasmas at rhic @xcite.
the study of the collective behavior of populations of interacting nonlinear oscillators has attracted the interest of physicists and mathematicians for many years since they can be used to modelize several chemical, biological and physical systems.   the aim of this paper is to study some pattern properties and get a quantitative estimation of the probability of pattern selection under arbitrary initial conditions or, in the language of dynamical systems, the volume of the basin of attraction of each pattern. keeping this goal in mind  , we will use the general results given in @xcite where assuming a system defined on a ring the authors developed a mathematical formalism powerful enough to get analytic information of the system. not only about the mechanisms which are responsible for synchronization and formation of spatio - temporal structures, but also, as a complement to proof under which conditions they are stable solutions of the dynamical equations, we present a 1d model of pulse - coupled oscillators that allows us to study analytically the most simple patterns and understand their mechanisms of selection.
we investigate the void size distribution function statistically in simulations using the cosmic void catalog ( cvc ) of @xcite.   we find that a specific standard parametric model can fit samples of void radii from the cvc after suitable estimation of the parameters in the model. using three mock catalogs, n - body mock, hod sparse and hod dense, we show that the system of @xmath0-parameter log - normal distribution provides a fairly satisfactory model of the size distribution of voids which is strikingly similar to the galaxy mass distribution of @xfite.
the prediction of the strength of the electrorheological ( er ) effect is the main concern in the theoretical investigation of er fluids.   recent experiments showed that the induced forces between the rotating particles are markedly different from the values predicted by the existing theories which have not taken the motion of particles into account. in order to explain this effect, we formulate a model, which describes the relaxation process of the polarized charge on the surfaces of the rotateable particles. using the multiple image method @xcite, we calculate the force between the polarized particles and show that the force is inversely proportional to the square of the product of the relaxation time and the angular velocity of the rotating particle.
coronal mass ejections ( cmes ) are the most important manifestation of solar activity that drives the space weather near earth.   they are also a fundamental mechanism by which the large - scale corona sheds flux and, hence, may play a central role in the solar cycle. since many cmes are accompanied by the ejection of prominences or filaments, it appears that the innermost flux of the erupting arcade overlying a photospheric neutral line opens out to the solar wind, but whether all the arcade flux opens or whether some inner field is left closed is a critical issue for any theoretical model for cme initiation. here   we present a new model for the eruption of a cme that can produce an eruption in which even the outermost arcade flux at the photospherical neutral line can open to infinity and, yet, the eruption is purely magnetically driven.. the model is based on the observation that the magnetic stress of the coronal magnetic field is slow compared to characteristic time scales in the corona, and that the eruption occurs quasi - staticly. as a good approximation, the energy for the cme is pumped into the coronia quasi - statically through two processes
we investigate the behavior of molecular spiders that move along one - dimensional tracks @xcite.   we assume that each leg of a spider steps independently and symmetrically to neighboring empty sites at rates 1 from revisited sites and at rates 0 from sites visited for the first time. in order to study the interplay between the spiders and their environment, we put a hat at sites which have never been visited earlier, i.e.  where the dna substrate is still un - cleaved. by simulating the slow - down of legs on newly visited sites, we obtain exact results for the so - called exited walk which additionally takes into account a bias on the new sites. using the same model, we find that the bipedal spiders with maximal leg distance @xmath7 are more likely to be multi - pedal spiders than the ones with a single leg.
the high velocity cloud ( hvc ) population of neutral hydrogen clouds that surround the milky way galaxy has been the subject of intense interest in recent years.   the lack of associated starlight and the absence of known distances to the clouds have hampered the calculation of their physical properties. here  , we calculate the probability that the narrow strip that the arecibo h  i  strip survey ( ahiss ) makes through the halos of @xmath8200 galaxy halos and @x Math814 groups would detect members of the hvc population in those systems. using the h i  mass function for the local group, we find that the probability of detecting hvcs in the region of the galaxy where the ahiss is conducted is 1.5 times higher than that for the field galaxy population with a faint end slope of ~10  cm, and 2.2 times higher for the region with a steep end slope > 10  cm.    the results are consistent with the existence of a large population of dark matter - dominated mini - halos in the galactic halo that have collected and remained stable on cosmological time scales.
abstractnonthermal emission is commonly observed among the lowest - mass stars, but a very rare set of low - temperature " hyperactive " dwarfs ( e.g., l5e and t6.5e ) exhibit unusually prodigious and persistent nonthermal emissions.   we report new observations of 2mass  j13153094@xmath02649513 ( hereafter 2mass j1315@x Math02649 ; @xcite ), a high proper motion l5E dwarf which has exhibited sustained but variable h@x math6 emission on no fewer than seven epochs spanning nearly a decade.  in addition, we observe near - infrared spectroscopic evidence for a brown dwarf companion at a projected separation of 7  au. using adaptive optics imaging and spectroscopy, we confirm the presence of the companion and allow determination of its separation and classification. based on comparison to evolutionary and atmospheric models, we also perform a coevality test to examine the reliability of these models.
levitation melting ( elm ) is a simple method for the levitation of a conducting sample in a coil fed by an ac magnetic field.   it is particularly useful for melting reactive metals with high melting points, for example such as _ ti _,   zr ,  v , and  v _, which often react with the crucible material and so get polluted by it. to achieve a successful levitation, the sample has to be stable at least to perturbations of sufficiently small amplitude. in this study  , we apply our previous theory to analyze both the static and dynamic stability of a spherical sample in more realistic axisymmetric magnetic systems made of a set of coaxial circular current loops alternating with circular frequency. using the gauge transformation for the 3d vector potential of the induced current loop, we find that the static stability of the sample is not sufficient for a good levitation because sometimes the sample exhibits overstability due to oscillations of arbitrary direction or to spin - up from its equilibrium position. on the other hand, when the coil is slightly perturbed the sample can be levitated and also melted if the coil configuration and the current in it are properly adjusted.
we reexamine the behavior of phantom models with negative kinetic terms, and we generalize previous studies to determine the asymptotic behavior of such models and the generic conditions for the existence of a future singularity.   we derive observational constraints on a subset of these models from the supernova data. in the case of a phantom model with a scale factor of @xmath15, we find that the density of the dark energy increases with increasing scale factor, and both the scale factor and the phantom energy density can become infinite at a finite @x Math14, a condition known as the  big rip ".. we also find that there is a solution to the coincidence problem for these models.
the extended mass spectrum of the known hadrons @xcite is used to explain the proton to pion ratio, @xmath1, at the lhc.   previous work has shown that the extended mass spectra can be used to match thermal models to the final state particle ratios and yields in order to determine the chemical freeze - out temperature and baryonic chemical potentials of the nuclear phase diagram. here   we explore the effects of this model using dynamical chemical reactions that are catalyzed by quickly decaying non - strange, mesonic hagedorn states driven through a series of multihadronic decay reactions driven through different types of decays ( e.g., gev, pions plus pions, n+pions, and pions + pions ) on the thermodynamics and chemical equilibrium values of the hadrons. for each type of reaction, we find that the results are better matched to those obtained using thermal models when the added resonances are present in the hadron gas phase due to the enhanced effect of the extendedMass spectrum.
we use detrended fluctuation analysis ( dfa ) to investigate the scaling behavior of long - time correlations in daily temperature data from 61 australian meteorological stations.   we find a general tendency for the correlation exponent to decrease with increasing latitude, but not with increasing altitude. at low altitude,   the scale invariance of the correlations is stronger for sea surface temperature than for air over ground, while at high altitude the scaling is more pronounced for land surface temperature. by using a second order linear autoregressive model  , we show that the scaling can be fully explained by the coupling of the atmosphere with the ocean, and that the magnitude of the scaling depends on the altitude of the meteorological station.
abstractthe life cycles of dwarf galaxies with present - day stellar masses ( @xmath13 ) illustrate many challenges to our current understanding of galaxy formation and evolution.   while we see that starbursts do not play an important role in the global star - formation at the present epoch @xcite, it is likely that the star formation histories of these dwarf galaxies are complex and varied, and that their typical star formation rates were higher in the past. here   we review the recent advances in our understanding of the history of star formation in these systems.
the discovery of afterglows to long - duration gamma - ray bursts ( grbs ) from star - forming galaxies at high redshifts in the pre-_swift era led to the expectation that the relativistic outflow of the bursts would be confined to a jet, and that the observed light curves should exhibit a break in the relativation of the jet.   however, the x - ray light curves of many grbs show no temporal break at all to late times, implying much more energy than expected. while the most extreme example to - date is that of grb060729, which continued a smooth x - rays power - law decline for 125 d, implying an opening angle greater than 28 degrees @xcite, the light curve now shows a possible break at @xmath10290 d : the nature of this break is not yet known.
the top quark is the heaviest fundamental particle known, and is a unique probe of physics at the natural electroweak scale.   the standard model ( sm ) predicts that top quarks are created via two independent production mechanisms in hadron colliders : the primary mode, in which a  pair is produced from a @xmath14 vertex via the strong interaction, was used by the d0 and cdf collaborations to establish the existence of the top quink in 1995  @xcite, and measure its mass.. the second production mode of top qu atoms at hadron Colliders is the electroweak production of a single top quek from a@xmath15 vertex.    the predicted cross section for single top production is about half that of  pairs, but the signal - to - background ratio is much worse ; measurement of the single top qcd production cross section has therefore until recently been impeded by its low rate and difficult background environment compared to the top pair production. in this paper   i describe the analysis that led to the observation of single top formation at the tevatron of @xcites by thed0 collaboration, and the measurement of their corresponding production cross sections.
we identify the stoichiometric natural superlattice @xmath2 as a semiconductor with a small bandgap of about@xmath13{ev}$.   its layered structure is confirmed by scanning transmission electron microscopy ( stem ) and x - ray diffraction ( xrd ), confirming a repeated stacking sequence of hexagonal, metallic bi bilayer ( bls ) and semiconducting @x math1 quintuple layer ( qls ) building blocks in a wide range of strong and weak topological insulators ( wtis and tcis ), respectively. we find two characteristic surface states of the tci on the ( 0001 ) surface, i.e., the metallic edge states inherited from the 2d ti but with an insulating surface plane ( the dark side ) normal to the stacking direction. for the wti,   the surface states are protected by time - reversal symmetry, while for the tcis the mirror - symmetry protected states are destroyed by a magnetic field.
the study of stars is one of the most fascinating topics in astrophysics because it involves many areas of physics : gravitation, thermodynamics, hydrodynamics, statistical mechanics, quantum mechanics, relativity,... and it has furthermore a very interesting history.   soon after the discovery of the quantum statistics by fermi ( 1926 ), eddington ( 1935 ) @xcite lays down the foundations of the subject and describes in detail the basic processes that govern the structure of ordinary stars. at that stage, only elements of " classical" physics are used and difficulties with such theories to account for the structures of high density stars such as the companion of sirius are pointed out. however, progressively, his early investigations on white dwarf stars were extended in general relativity to the case of neutron stars and finally led to the concept of " black holes", a term coined by wheeler in 1967. in this review,   we focus on the development of relativistic white dwarf star theory from the perspective of the late chandrasekhar ( 1934 ), who first discovered the limiting mass of a self - gravitating degenerate electron gas of electrons below a critical temperature and then showed that it is equivalent to
we propose a model for evolution of a population of haploid organisms defined by their genomes, and subject to competition, asexual reproduction with mutation, and selection.   we develop a mean - field description, which describes the evolution of an infinite population exactly, since it has no spatial structure. in order to study the consequences of variation of conditions affecting survival, related to environmental flexibility, and the genetic variability of the population, we also perform monte carlo simulations for the model. using these simulations, we determine the survival / extinction phase boundary, and compare the temporal evolution, and its genomic distribution, predicted by mft against simulation results.
the solvent mediated interaction between two hard walls immersed in a hard core yukawa fluid is investigated by means of numerical simulations.   the effective force between two walls acquires the range of the correlation length of the underlying critical solvent and is described by a universal scaling law which depends on a very limited number of features ( e.g. the geometry of the bodies, the boundary conditions at the colloidal surfaces, the system dimensionality ). within our approximate density functional theory ( dft ) formulation, the critical casimir scaling function is deeply related to the universal bulk properties of the critical fluid. as a result  , we propose a weighted density approximation ( wda ) especially designed for being accurate also near the critical point. this theory is validated against other dft prescriptions as well as available numerical simulations in several states.    the development of long range tails in both the density profile and the effective forces is quantitatively investigated. 	 the emergence of scaling laws is investigated in the critical and regime.
a recent paper ( gupta et al.   ( 2012 ) has argued that the milky way galaxy has a large - scale, massive, warm - hot gaseous halo around it, extending over a region with a radius larger than 100 kpc and that the mass content of the gas with a temperature of@xmath0 k is greater than @xmath1, comparable to the total baryonic mass in the galactic disk and accounting for the bulk of the missing baryon matter in the galaxy. as will be detailed in the following, both the measurement procedure and the simplistic inference of the work are very problematic. the results and conclusions are inconsistent with many previous studies, some of which are based on more or less the same data sets.. indeed, mathur ( 2012 ; paper ii hereafter ) very recently reviewed some of these inconsistencies, mostly by criticizing some of those previous studies. however, this review is highly biased and in fact contains numerous errors due to mis - reading and/or mis - interpreting the studies. in this paper  , we show examples of these, based on quick fact - checking and analysis of relevant issues.
the weak - field approximation for the radiative transfer equation for polarized light in the presence of a weak magnetic field is known as the " weak field approximation ".   it is a simple way to relate the emergent stokes profiles emerging from every point of the visible surface with the magnetic field vector and is applicable in many scenarios, including the case of a rotating star with a magnetic field on its surface. here  , we show that it is possible to obtain analytical expressions for the stokes vector fluxes in the weak field limit by taking into account the correlation between the magnetic fields and the line - of - sight velocity. this will facilitate the application of bayesian inference codes, like the one developed by @xcite, that are based on markov chain monte carlo methods that need to carry out the synthesis thousands of times to sample the posterior distribution.
we review the use of fredholm methods for the calculation of husimi distributions of stadium eigenfunctions in terms of classical invariants.   we show that the semiclassical approximation that is based on the approximation of the traces and powers of the propagator as sums over the periodic points of the underlying classical system is the most efficient one for the quantization of billiards eigenfunction @xcite.
@xmath0-cdm model of the universe has been investigated by selecting a specific time - dependent form of @x Math0, viz.  , @xmath6 along with @x maths7. in this model,   the equation of state parameter @x math2 is taken as a constant and the energy density of dark matter @xcite is determined by the cross section of interaction of evaporated particle.    the maximal estimation of this cross section gave the time variation of @Xmath0  @xcites, leading to possible realization of our model in the form @xMath9.. the change in sign of the deceleration parameter q has also been shown in this case which refers to the evolution of the cosmos via a phase transition from decelerating to accelerating. 	 interestingly the expression for negative energy density obtained in the present model is negative. however, this type of negative density is not at all unavailable in the literature.
cepheus a east is a well - known site of star formation that contains a series of heavily embedded far - infrared and radio - continuum sources, one of which dominates the luminosity of the entire region.   previous results have shown that the multipolar outflow existing in this region consists of complex structures of shock - excited atomic and molecular gas. here   we report the first detection of gas - phase co@xmath0 emissions and line emissions from ionized species along high - velocity ( hv ) and extra - high - velocities ( ehv ) outflows, indicating the presence of both dissociative ( j - type ) and non - dissociation ( c-type ) shocks, likely resulting from successive episodes of activity. using spectral maps obtained with the infrared spectrograph ( irs ) onboard the _ spitzer space telescope _ ( _ sst _ ), we show that the source of the hv jet at cepheus a east can be found to be either the protostellar object hw2 ( 2.5 @xmath410@x math6 @x Math6 ) or the proton - driven exotoxin h@x maths0o ices
the non - linear evolution of the nova outbursts is studied using a radial, non - adiabatic linear stability analysis and adaptive - grid radiation hydro - code ( rhd, dorfi & feuchtinger 1991 ).   the results show that the pulsational stability of such a structure is very different from that of classical pulsators on the instability strip, and that the rate of growth rates found are of the same order as the free - fall time - scale for an extended range of @xmath3. in contrast to classical pulsator experiments,   this is the case not only for model b, but also for models c and d. the latter two models are particularly interesting because they contain complex conjugate pairs of eigenfrequencies around the centre of the instability region, which are almost perfectly reproduced by the non - adsiabatatic reversible approximation. during the linear growth, and more so lateron, an additional energy transport is observed, as packets of radiation energy are spiralling outwards in density perturbations ( similar to a " screw conveyor " ).
we present a model within the self - consistent hartree approximation that allows us to describe the nonlinear screening and evolution of the conductance plateaus out of equilibrium and thus uncover underlying microscopic origin of the observed features in the differential conductance. to solve the schrdinger equation we employ a standard non - equilibrium green s function ( negf formalism @xcite.   we demonstrate that for @xmath9 the differentialconductance exhibits a @x Math10 plateau ( as opposed to the @x math11 plateau predicted by the noninteracting theories glazman, frost_berggren, kothari, chen ) and that in the regime of@xmath12 the non linear screening causes the half - integer plateaus to bend upward as the source - bias voltage increases from @x maths1 to @xMath1. the bending can be clearly seen in all cases where the gradient voltage between the source and drain electrodes is applied at a bias voltage of @x x = 0.5 mv.
the three - dimensional map @xmath6 is a natural generalization of the famous two - dimensional hnon map @xcite.   this map is quadratic, has constant jacobian, and when it reduces to the two - dimension h non map, it is called the  _   3d hnonmap. " in this paper we will study a number of properties of (  ), including :   1. its nontrivial dynamics and, most importantly, the existence of _ wild - hyperbolic _ strange attractors ; 2.   its origination in homoclinic bifurcations ; 3.  = its structure as a member of the family of three -dimensional quadrastic maps with constant jacs.
the galactic halo star sdss j090745.0 + 024507 ( hereafter hvs ) has a radial velocity of @xmath8.   the only plausible mechanism for achieving this extreme velocity is ejection from the vicinity of the central supermassive black hole ( cbh ), as predicted by @xcite. in order to search for photometric variability and so pin down its properties, we performed precise photometry of the hvs using the mmt 6.5 m telescope during two nights ( ut 2005 january 15, april 13 ) with the megacam ccd camera@xcite, and during four nights ( u 2005 January 13, 15 - 17 ) with an 1.2-meter telescope at flwo. here   we describe our observations and data reduction in  .we find that the star is indeed variable, and we constrain the variability to be short - period and low - amplitude. together with the measured effective temperature, we argue in   sec : slow pulsating b ( spb ) stars that pulsate with periods of the order of one day, so - called main - sequence stars.our observations resolve the two - fold ambiguity
we investigate the shear - induced behavior of a thin film of brownian spheres which, already in equilibrium, forms a crystalline lateral structure with square symmetry.   the system is studied on the basis of overdamped brownian dynamics ( bd ) simulation without hydrodynamic interactions ( following various earlier studies on dense systems under flow @xcite ) and the resulting single - particle dynamics is compared with experimental data..the results show that the particles in the middle layer of the thin film form a laned state at shear rates in between the initial square state and the subsequent shear melting. moreover, the laning is accompanied by a transformation of the ( originally flat ) middle layer into two sublayers. this is in sharp contrast to the behavior of bilayers ( and also of bulk suspensions ) where the layers always remain flat@xcite.
the problem of calculating the radiation spectrum produced in the atmosphere of an unmagnetized, accreting neutron star ( ns ) has received wide attention in the past.   the commonly accepted picture is that the emerging spectrum is essentially a blackbody plus a high  energy compton tail. in this paper   we show that a new class of hotter equilibrium solutions may exist if the accretion luminosity exceeds a certain critical value, in analogy with what has been already found in black hole accretion. to get some physical insight without resorting to a full time   dependent calculation, we consider the stationary case and analyze the effects of different processes separately. using the characteristics method introduced by zane et al. ( 1996, paper iii ), we calculate the radiation field and the frequency  dependent transfer equation coupled to the hydrostatic and energy balance.    the resulting intensity is then used to estimate the pair number density produced by photon   photon interactions. although not fully self - consistent, this approach shows that a large pair production is expected in the external atmospheric layers, which opens the possibility that such configurations are unstable with respect to the onset of a radiatively  driven wind, produced by the increased opacity in the pair
in the last years we have proposed the analysis of coherent hadron - hadron collisions as an alternative to study the quantum chromodynamics ( qcd ) dynamics at high energies using the saturation model proposed by golec - biernat and wsthoff ( gbw ) several years ago @xcite.   this model has been improved recently considering the current state - of - the - art of saturation physics : the color glass condensate ( cgc ) formalism. in this paper   we revise our predictions for @xmath1 production in coherent@xmath0 collisions and present, for the first time, predictions for the @x Math2 production in coerent collisions considering the cgc formalism.the results show that the new predictions are consistent with the observed signals of parton saturation observed at the large hadron collider at cern both in deep inelastic scattering at hera and in deuteron - gold collisions at rhic. however, they are not conclusive evidence for a new regime of the qcd dynamics under investigation at the lhc.
we investigate the applicability of existing video quality metrics in the augmented reality space and correlate encoded video quality with subjectively rated perceived video quality levels.   we provide a high  level overview of subjective quality ratings for longer movie segments performing an initial view at the underlying characteristics at play, focusing on the evaluation of video compression quality without potentially lossy network transport when viewed in a scenario where binocular vision is augmented. using off - the  shelf ( cots ) head  mounted display ( hmd ) technology, we provide users with a see  trough cots hmd that displays video sequences at different target bit rates and user select different encoder properties at the target rate points, resulting in a combination of frame rate and compression. to evaluate the perceptual video quality, we use mean opinion scores ( mos ) obtained from multiple human test subjects according to  @xcite as a measure of visual objective or perceptual qualities employing cots see  through devices and consider the existing standard as outlined in recommendation itu  t bt.50013@xcite. here, we demonstrate that the performance of the proposed video quality metric can be used to assess the quality of video data delivered to the cots system by means of a
the deformation - dependent mass ( ddm ) bohr hamiltonian @xcite with a davidson potential is presented, in which the nuclear mass depends on the deformation through a specific function containing a free parameter, @xmath3.   the purpose of the present work is to examine the physical relevance of this free parameter by embedding the 5-dimensional ( 5d ) space into a 6d space, thus connecting the ddm free parameter to the curvature of the 5d space and thus connecting it to the classical limit of the most general interacting boson model ( ibm ) of arima and iachello@xcite, which is known to possess an overall u(6 ) symmetry in a six - dimensional ( 6d )space, thus attributing to it a specific physical meaning.the results show that the ddnm free parameter is not a mathematical trick introducing an extra parameter, but a necessity arising from concrete physical requirements.
the transition to turbulence is one of the least understood phenomena in fluid dynamics.   we present a study of turbulent - laminar banded patterns in plane poiseuille flow, which are observed numerically and experimentally in counter - rotating taylor - couette flow @xcite and in plane couetteflow@xcite. in the present paper  , we extend this work using methods previously employed to study these patterns in planes couette flows, and describe their evolution in time, propagation velocity, and the balance of forces they entail. for the latter, we use a computational domain with dimensions of 51.2 by 22.5 in the streamwise direction and of 24.0 by 24.9 in the spanwise direction, tilted with respect to the bulk velocity, to capture the same pattern that has been observed experimentally at different angles and wavelengths in both types of flow. as a result, we find that the frequency of the turbulent bands increases with speed, and that the propagation velocity of the bands increases linearly with speed ; however, the propagation velocities of the jets are not affected by the speed of the waves themselves. on the other hand,   the propagating velocity of
mass - loss from massive stars in the red supergiant phase is fundamental to the chemical enrichment of the interstellar medium @xcite.   red supergiants, with initial masses of 10@xmath250@x Math3, are known to lose mass at rates of up to 10@Xmath4/yr @xaite. here   we use interferometric measurements of the continuum angular diameter of betelgeuse ( @xmath5 orionis, spectral type m2iab ) and  lines to investigate the physical processes involved in mass - loss by comparing the spectra of the star with those of the atmosphere of the circumstellar envelope as viewed across the _ jhk_ wavelength bands using a ` lucky - imaging'approach combined with adaptive optics. for the first time  , we show that the dust condensation zone surrounding the star is not only dominated by cool photospheric gas, but also by asymmetrically - distributed hot chromospheric material, which can be found at rest with respect to the star. on the surface of the stellar disk,   the presence of these two types of material is attributed to large - scale surface convective activity.
the possibility to design efficient sources of terahertz ( thz ) radiation attracts the attention of researches working in various scientific fields.   the current use of thz radiation includes fields such as medicine, security, biosensing, and others   @xcite. however, none of the currently existing thz emitters universally satisfies the application requirements. until now, thz sources operating in the spectral region around 1thz remain costly, show limited quantum efficiency and operate at very low temperatures. recently  , it was proposed that the efficiency of a thz emitter can be drastically increased by using the phenomenon of bosonic stimulation. in this article   we present the theory of an efficient thz laser based on the two - photon optical transition between 2p and 1s exciton states @xmath2 and@xmath3, embedded within a planar microcavity supported by a photonic mode with energy @x math4 tuned into resonance with the 2p exciton state.we consider the system formed by a quantum well supporting a 2pexciton state with energy ~2 kcal / mol and a 1sexcitation state withenergy ~1 kcal /mol, embedded inside
the jaynes - cummings ( jc ) model is often used to describe the interaction between an electronic / atomic system and a single - mode quantized electromagnetic field.   the jc model fails in the ultrastrong coupling regime where the photon - matter coupling strength reaches a considerable fraction of the energy of a single cavity photon. using the method described later in this paper  , we have been able to calculate time dependent electron transport through a photon cavity @xcite and to test the validity of the jacobson-cummings model in the ultraastrongs coupling regime. with our approach   it would be relatively easy to add a time dependent perturbation to the closed system and integrate the equation of motion numerically. choosing the frequency of the perturbations such that the external magnetic field does not have time to adjust adiabatically, it is possible to investigate non - adiabsorbable dynamics related to the dynamical casimir effect where photons can be excited out of vacuum in correlated pairs.
the new results from super - kamiokande ( sk ) atmospheric neutrinos experiment and the new result from k2k accelerator long baseline neutrino experiment are presented in this paper.   the observations by sk show that the observed number of muon neutrines is smaller than the monte carlo ( mc ) prediction, and the zenith angle distributions are well explained by neutrini oscillation.    the new results are based on 1,489 live - day exposure of the sk experiment.
we present a new representation for finding the zeros of a system of two bivariate polynomials of degree.   the first representation uses the tree structure of monomials in @xmath26 and@xmath27, and the resulting matrices are smaller than those of @xcite, with the same asymptotic order (  = 0 \end{split}=0 \det(a_2+x b_2 + y c_2)&=q(x, y ) ; this representation can be used for both monic and polynomial multiparameter eigenvalue problems that could be solved by the standard tools like the qz algorithm, for instance in the ` roots ` command in matlab  . the second representation is even more condensed, with asymaptotic order, and can be applied to scalar bivariate Polynomial systems.
jets and equatorial tori are among the most prominent morphological features of proto - planetary nebulae ( proto - pne ).   they are also relatively common, but their origins are uncertain. in this paper   we attempt to make connections between the observed characteristics of the jets and tori, and various theoretical ideas on how they might form. by estimating the kinematic ages of each component of the jet and the tori in the time domain, we find evidence for a torus - jet sequence. in the second part of the paper, we use this relation to evaluate different formation scenarios : it favors and constrains certain scenarios, and rules out others.
the arrival of dna and protein sequence data in the last forty years has led to explosive growth of phylogenetics.   many of the modern phylogenetic methods consider sequence data under probabilistic models of sequence evolution. for such models to be useful for phylogenetic inference, it is important to establish their  identifiability  ( i.e., to show that nonisomorphic trees or different model parameters can not induce the same distribution on the sequences at the leaves under a given model of sequence evolutionary evolution ). while phylogenetic trees represent relationships between species, population pedigrees represent how individuals within a population are related to each other. here   we present a statistical and combinatorial foundation for the problem of reconstructing pedigree from observations ( sequences ) on extant individuals using a biologically realistic model for sequences undergoing mutations and recombinations, and show that the results are consistent with those of the well known @xcite results.
the falling procedure of thin liquid sheets is a complex process that involves the breakup of a network of ligaments into several number of small droplets.   two of the crucial parameters for the case of falling droplets are size and velocity of the fragments. in this video,   the effect of the vorticity magnitude and the radius of curvature on the falling velocity and size of the fragment is demonstrated.    the results obtained via direct numerical simulation are presented.
oxidative adsorption of oxygen on the ( 001 ) surface of rhodium has been studied using stm experiments and density functional theory.   we find that the preferred adsorbed site is the _ hollow _ one, at the center of the square formed by four first - layer rhodia atoms. in agreement with experimental findings  , we also find that it is the  white  squares which rotate rather than the  black  ones, as previously suggested by spa - leed and @xcite. this distortion can be rationalized by a simple chemical model of the re - bonding of o atoms at the surface.
the presence of impulse - like noise in speech can significantly reduce the intelligibility of speech and degrade automatic speech recognition ( asr ) performance.   one difficulty with removing impulse noise from speech is the wide temporal and spectral variation between different parts of speech, such as the periodic and low - frequency nature of vowel signals and the random and high -frequency nature of consonants. to overcome this problem, we have developed a novel approach to detect and remove impulse noise by using the wavelet transform domain for detecting and suppressing impulse noise at finer scales. on the basis of the impulse detected in the finer scales, the corresponding wavelet coefficients of the impulses at the coarser scales are attenuated. our experiment results show that the impulse noise is significantly suppressed without degrading the speech signal or introducing any audible artifacts.
the far - infrared ( far - ir ) emission from the ionised gas in the lockman hole region of the equator is a very diffuse source of dust emission.   we have used two independent gas tracers for the high - performance liquid chromatography and mass spectrometry ( hi and h@xmath2 ) to determine the far -ir emission at 100 @xmath1 m. the results are in good agreement with those of the first determination (  @xcite ), but the cfirb value of 0.78 mjy / sr is smaller than that derived here since the assumed wim dust spectrum was overestimated below 200  @x Math1 m and the estimated dust temperature was too high.
the appearance of cluster states in atomic nuclei is a ubiquitous phenomenon with many implications for both nuclear physics and astrophysics.   while several factors are known to contribute to clustering, a comprehensive microscopic understanding of this phenomenon still remains elusive. in this work, we use density functional theory ( dft ) to characterize cluster configurations in deformed light nuclei using a simple harmonic oscillator scheme and skyrme - dft. the results for fissioning heavy nuclei are presented in sec. .
the recent discoveries of ultracool stellar dwarfs and brown dwarfs have produced a need for an extension of the current system of stellar classification, whose latest spectral class has been m since near the very inception of classification.   new spectral classes designated l and t have been proposed and are widely used now to describe the ultracolumnacool dwarfs. in this paper   we describe a unified classification system that we have developed for l and T dwarfs using new and published spectra of 25 l and 17 t dwarfs in the 0.6 - 2.5  @xmath0 m region. based on these spectra, we have found four indices that are monotonic across large swaths of the L and t sequences, based on individual spectral features or on continuum behavior over relatively narrow wavelength regions, and measurable at sites with average atmospheric transparency and intermediate - sized telescopes. by combining these indices with the optical ( 0.61.0@x Math0 m ) and infrared ( 1.02.5 @xmath1.2   m ) indices we have also found that two of the most useful indices are associated with prominent water bands and two with prominent methane bands.
the ion current through a voltage - sensitive large conductance locust potassium channel ( bk channel ) was measured by the patch clamp technique @xcite with a sampling frequency @xmath2 khz and at a 60 mv voltage.   the resulting time series have been subjected to both a detrended fluctuation analysis ( dfa ) and an autocorrelation function analysis ( afa ). as ion current recordings can be also treated as a superposition of two signals, i.e. closed and open states dynamics, we have applied this dfa technique to a time series of ion current from the bk channels. in the dfa analysis, the ion current probability density function ( pdf )   has been used to determine the presence of long - range memory effects occurring in the closed state of the channel, which is shown to be associated with the high current values observed in the open state. for the afa analysis,   data sets from cell - attached patches of adult locust ( schistocerca gregaria ) extensor tibiae fibers are discussed.
the absorption of energy from the laser field by electrons in rare gas clusters @xcite is studied.   the mechanism(s ) of this absorption are identified and compared to the collisionless absorption mechanism ( collisional absorption ), which is the dominant one at near infrared wavelengths @xmath0 nm or greater, and to the nonlinear resonance ( n ) that is assumed to be the dominant mechanism at very short wavelengths @Xmath1 nm or less. for a few hundred femtoseconds of laser light irradiation,   both modes of absorption are found to be independent of each other. during the expansion of the ionic core  , the decreasing charge density leads to the decrease of the mie plasma frequency, leading to the conversion of electron energy into ion energy. with the increasing outer ionization, the restoring force of the ions counteracts ionization ignition so that the net positive charge left behind finally explodes due to the coulomb repulsion and hydrodynamic pressure, resulting in the formation of a non - neutral plasma.
during the archean eon ( @xmath0gya ), when life on earth is thought to have first emerged, the sun s rotation period was 6 - 15 days, in contrast to its current 27 day period @xcite.   the topology of the solar surface magnetic field and the solar wind structure would have been very different from that of the present day sun, since the faster the rotation the higher the magnetic activity and related uv - x - ray luminosity. here  , we extend the work done by@xcite using a magnetohydrodynamic wind model and a surface magnetic fields consistent with observations of young active stars, and show that the interplanetary magnetic field for the early sun was not as strong as it is today, and the rate of solar wind mass loss was not more than 10 times that of our current sun. based on these results, we propose that the solar magnetic activity of the young sun may have had a significant influence on the cosmic ray ( cr ) exposure of earth through time.
we report basic results of our work on the soft ( 0.5 - 2 kev ) x - ray luminosity function ( sxlf ) of agns and its evolutionary properties, using a combined _ rosat _ sample of about 670 agns.   we have constructed a combined sample from various rosat surveys, ranging from the rass to the rosat ultra deep survey on the lockman hole. using the maximum - likelihood method, we have fitted the unbinned sample with a number of sxld models, including the pure luminosity evolution ( ple ), pure density evolution ( pde ), and the luminosity - dependent density evolution(ldde ) models. for the ukd and marano samples,   the overall fit has been made for the redshift range @xmath19 and@xmath20. for both the pspc and hri data, the overall fits are better than those for the ldde model. for each of the other models, the fit is better than that for the ple model, but not for the pde model. in the case of the lockingman hole, the best fit is obtained for the seyfert nucle
nematic colloids with different types of surface chemistry ( homeotropic or planar ) are produced by the use of topographic patterned surfaces as templates for the assembly of liquid crystal ( lc ) colloids into mesoscale structures with controlled symmetries.   the structure of the nematic lc host is determined by the interaction between the colloidal particles and the lc molecules, which is highly dependent on the symmetry of their pair - wise interaction @xcite. in this paper   we show that the repulsion from flat surfaces may be turned into an attraction or further enhanced, providing a mechanism for particle selection in nematic colloid structures based on their surface chemistry. by combining the surface topography ( concave or convex ) and the anchoring conditions ( perpendicular or parallel )  , we show how the short - distance repulsion against flat surfaces can be turned to an attraction if the confining surface exhibits concave topographic patterns with a shape complementary to that of the collological particle.. the results suggest that the effect of the surface chemistries of the compining surface on the size and shape of the nanoparticles can be tuned by adding photosensitive azobenzene
adaptive - kernel smoothing ( aks ) is a technique that allows the kernel of the measured data to vary over the image and adopt a position - dependent'natural'size.   it is particularly useful for smoothing images that feature real structure on various scales, some of which may be much smaller or much larger than the kernel size. in this paper  , we review the history of aks and discuss its applications in the analysis of two - dimensional event distributions using high - resolution astronomical data.
microlensing of the galactic halo is a powerful tool for studying the distribution of dark matter in the galaxy.   we have previously reported a survey of small fields in m31 ( crotts & tomaney 1996 ) that revealed several candidate microlensing events at roughly the predicted rate, and discussed what efforts have been required to verify the nature of these events. here  , we present results from a wide - angle survey of the halo over a large fraction of a square degree of m31, simulating a survey in which roughly 0.5 square degree is imaged for two hours every night on a two - meter telescope, in 1-arcsec seeing, requiring each event to be sampled at the 4@xmath12 level over at least 3 day timescales.    the event rate predicted for such a survey is large e.g. for a typical model model with a lensing mass of 2.5  kpc out into the disk, we find that the observed event rate is about twice as high as the predicted, and the expected event rate over the entire survey area is about three times higher than the one predicted. given the robust nature of some of the candidate
double parton scattering ( dps ) for hard processes gained recently a new impulse related to the experiments at large hadron collider ( lhc ) @xcite.   the dps contributions were discused for several reactions to mention double drell - yan, creation of @xmath0, etc. in our opinion, at present some efforts should be made in order to make the studies of dps processes really quantitative and differential in kinematical variables. in this letter   we wish to explore exclusive four - jet sample where the situation in the context of searching for dps should be even better. with the present cuts used in the cms analysis@xcite the dPS contribution can be of the order of 10 - 20%.. it could be still somewhat enhanced imposing further cuts on transverse momentum of the dijets or azimuthal angle between jets. 	 we discuss how to maximize the d ps contribution by selecting relevant kinematics.
the pseudospin symmetry of the dirac hamiltonian for antinucleons embedded in nuclei @xcite is studied by means of charge - conjugation and @xmath0 chiral transformations.   the main motivation of this paper is to shed some light on the relation between spin and pseudospins symmetries obtained by these transformations. as a result  , we show that the charge - Conjugation transformation can be used to relate the spin symmetry of negative bound - state solutions ( antinuclears ) to the pseudospinal symmetry of positive bound - states solutions ( nucleons ).. the results are compared with those of the @x Math0 chirality transformations, which are based on sum rules calculations in relativistic chiral models.
we study the zero temperature ( t ) phase diagram of a quasi-1d imbalanced fermi system as a function of the mismatch @xmath3 between their fermani wavevectors.   we show that including induced interactions through a random phase approximation ( rpa ) is essential to correct the mean - field ( mf ) pairing fluctuations results, since they give rise to a finite critical field separating a fully polarized phase from the fulde and ferrell   ( fflo ) phase. in the limit of short lifetimes,   the rpa can be used to obtain the correct results.
lattice simulations of the strangeness content of the nucleon, the infrared region of the landau - gauge gluon propagator, the long flux in @xmath0, the rich glueball spectrum, and the static - quark potential for quark - antiquark separations as large as 4 fm are presented.   the results are summarized.
accurate distances to planetary nebulae ( pne ) are critical for calculating the size, mass, luminosity, age, and other properties of pne and their central stars.   we report the detection of the systematic expansion of ngc  6543 between 1994 and 1997 from hubble space telescope ( hst ) archival observations. in order to quantify the magnitude of the angular expansion rate, we present three separate astrometric analyses of these recorded images. using a spatiokinematic model of the nebula derived from independent measurements of the doppler velocity, we obtain three direct distance determinations, all of which are in excellent mutual agreement. in addition, the expansion pattern reveals that the kinematic ages of features approximately scale with their angular size. this provides insight into the highly organized and orchestrated mass ejection behavior of this extraordinary nebula.
the azimuthal asymmetry of quark jet production in deep inelastic scattering ( sidis ) is studied using the collinear expansion technique @xcite.   the effect of initial and final state interaction of the parton before hadronization is taken into account and the spin and/or nuclear dependences of the sidis cross sections are calculated.    the results show a higher twist effect proportional to the transverse momentum dependent ( tmd ) parton matrix elements of the nucleon or nucleus than the twist-3 tmd parton correlation function.
we examine the mass spectrum of the @xmath3 hybrid exotic meson based on lattice quantum chromodynamics ( qcd ).   we utilize the outcome of a numerical simulation, gauge field configurations and quark propagators, which had been previously generated to study hybrid exotic decay widths using the maximum entropy method ( mem ) @xcite. in order to set the physical mass scale, standard local zero - momentum meson operators of the form@xmath12 were employed for the pseudoscalar meson, the vector Meson, and the vector meson. at one value of a global gauge coupling and four values of global hopping parameters,   the results are compared with those of the decay width calculation using the same method. as a result  , we find that the results obtained from the simulations show that the observed mass spectrum is not only consistent with the theoretical model, but also with the experimental model.
the ability to discriminate quantum states is important for quantum information transfer and processing.   it can serve as an efficient attack on quantum key distribution @xcite. in this paper   we present experimental realization of a simple version of the unambiguous identification of coherent states proposed by van enk et al.  in which the uknown coherent state can equal to whichever of two different program states.. the number of program states can be increased by extension of the basic experimental scheme, where the set of specimen states is determined by a quantum " program ".    the results show that the optimal choice of the splitting ratios is shown to be @xmath18 ( independently of the input states ).
a nonlinear differential effective dipole approximation ( ndeda ) is presented to investigate the effective linear and nonlinear dielectric properties of composite media containing nonlinear graded spherical particles ( inclusions ).   the model is based on a quasi - static approximation, under which the whole composite medium can be regarded as an effective homogeneous one with effective linear dielectic constant and effective third - order nonlinear susceptibility. using a first - principles approach, we derive the exact solutions for composite media having power - law gradation profiles inside the inclusions, which are then followed by the numerical results.
we study the heating of a cool core by cosmic - rays ( crs ) injected through the activities of the central active galactic nuclei ( agns ).   we find that the heating is mediated by non - thermal emission from the crs and the agn activities that are responsible for the acceleration of these crs.    the results of our calculations are in good agreement with observations.
the quantum effects of matter fields in curved spacetime are important for studying cosmology and black hole physics.   the hawking effect is one of the most famous examples of such a phenomenon, which is observed in a perfect fluid with a sonic horizon. in this paper  , we investigate the applicability of the analogy between hawking radiation and quantum effects in bose - einstein condensates ( becs ) in terms of the bogoliubov - de gennes equations as an extension of the theory of quantum physics in curved Spacetime. by exactly relating the quanta of the scalar field in spacetime with the bogolibov quasiparticles in bec,   we show that the Hawking effect is not restricted to gravity fields but also to other field theoretical phenomena in curved spacetime, including cosmological particle creation.
the cdm model of the origin and evolution of the universe has been a great success in the 80 s.   however, since its appearance it has been shown to have several deficiencies, namely : ( 1 ) the strong clustering of rich clusters of galaxies far in excess of cdm predictions ; ( 2 ) the overproduction of clusters abundance ; ( 3 ) the conflict between the normalization of the spectrum of the perturbation which is required by different types of observations ; ( 4 ) the incorrect scale dependence of the galaxy correlation function on scales @xmath18, on scales having too little power on the large scales compared to the power on smaller scales ; ( 5 ) the overestimation of the velocity dispersion of galaxies on scales@xmath22 times larger than that predicted by the cdm models ; ( 6 ) the misclassification of the temperature function of clusters as a function of the critical matter density ; ( 7 ) the non - linearity of the vdf ; ( 8 ) the poor agreement between the observed and predicted values of the rms fluctuations within spheres of radius for the galaxy angular correlation function given by the qdot survey and the 1.2 jy iras power spectrum ; ( 9
the jet studies are known to be a good tool to test perturbative qcd effects.   unfortunately in practice, due to unavoidable cuts on transverse momenta of jets, one samples rather large values of the gluon longitudinal momentum fraction @xmath0, where it is not completely clear what is the underlying dynamics and in particular what unintegrated gluonic distribution should be used. here   we have explored dijet azimuthal correlations at the parton level for quark - antiquark dijet production based on the unintegration of the unfriendly gluonal distributions found recently in @xcite. using the data from the phenomenological analysis of @x Math1 we have extended the study of the jet production beyond the familiar collinear approximation and have focused on how more exclusive and more differential jet production observables probe the unobegrated gjorken distribution.
we study the local quantum uncertainty in critical systems considering two spin-@xmath3 chains, described by the anisotropic @xmath1 hamiltonian and the model with three spins interaction, named @x math2 model, which contains the spin - liquid phase @xcite that only recently could be experimentally investigated.   we consider the zero temperature case, making some comments about finite temperature in the last section. for both models, we find that the lqu is reduced to the minimum value that could be attainable in a measurement of a local observable at a critical point, while it is increased to the maximum value at the transition point if the system is not excited by the thermal fluctuations. as a consequence,   the correlation length of the quantum correlations between the two models diverges at this point, suggesting that the latter should be considered as a good indicator for the critical behaviour of the model.
the thermal expansion of bismuth at equilibrium is well below the melting temperature of isotropic@xcite and anisotropic solids.   however, the development of strain from coherent acoustic phonons on a picosecond timescale is still poorly understood and has never been addressed by ab - initio calculations. in this paper  , we show that the thermal expansion tensor of bistsuth can be predicted by first - principles calculations using the quasiharmonic approximation where the atoms of the crystal are considered to undergo harmonic oscillations, but with frequencies that depend on strain. when spin - orbit interaction ( soi ) is included in the calculations, the calculated thermal expansion coefficients are in good agreement with experimental results obtained by measuring the sound wave velocities for different directions and polarizations as well as with calorimetry measurements.. the role of the elasticity and the anharmonicity in the anisotropy of these coefficients is also discussed.
chromospheric evaporation was first suggested by @xcite to explain the origin of the hot, dense, soft x - ray ( sxr ) emitting plasma confined in the coronal loops during solar flares.   we report in this paper our analyses of the spatial and spectral evolution of a simple flare on 2003 november 13 with excellent coverage of the reuven ramaty high energy solar spectroscopic imager ( _ rhessi_ ). because the flare occurred near the solar limb it presented minimum projection effects and a well - defined loop geometry that allows direct imaging of the hxr brightness profile along the flaring loop. using data obtained from the _ r Hessi  , we show that the evapration front moved toward the loop top ( lt ) during the impulsive phase, which is the horizontal counterpart of the line - of - sight motion revealed by the blue - shifted emission lines observed simultaneously by _   yohkoh_/bcs. the time course of these motions is similar to that observed by the uv - sxR spectral lines produced by the evaporated plasma, as well as the density and temperature profiles along the fringes of the fl
metallicity measurements of the host galaxies of all long gamma - ray bursts ( grbs ) known at low - redshifts provide us with an important clue to study the relation between metallicity and long grb occurrence rate.   however, the relationship between metalicity and short - term events such as long grbs is not well understood quantitatively. in this review,   we present a new approach to investigate the association of metallic properties of longgrb host galaxies with long gr b occurrence rate by comparing the properties of these galaxies with those of general galaxies at high- and high - redshift redshifted galaxies. using the unbiased surveys, we show that the metalliciticity distribution of the longgfb host galaxies at redshifting @xmath4 is significantly biased towards low - metallicities compared with star forming galaxies at similar redsh shifts, suggesting long grps really occur in low - metallically active environments. on the other hand, we find that the distributions of longgabrls and x - ray flashes, which are observed in the unbiased survey, are not necessarily identical to those of the progenitor galaxy at red shifts@xmath7,
the band structures and optical constants of the hexagonal and face - centered - cubic phases of the gst chalcogenide have been calculated by means of the density - functional theory using plane waves as basis set.   the electronic structure has been computed using the dft equations that are implemented in the quantum espresso 4.1 code  @xcite, and the electron - ion interactions have been described through the norm - conserving ionic perturbation theory ( dfpt ). from this, it is possible to evaluate the sound velocity and the thermal conductivity, which compare well with experimental data on the phonon contribution in hexagonal gst. moreover, the heat capacity for this phase is obtained over a wide temperature range ( 5 - 870 k ) by integrating the dos.
a growing body of mathematical research has demonstrated that one of the most popular logic puzzles in the world, sudoku, has a rich underlying structure.   we consider various symmetry groups for the more accessible variant of sudaku, shidoku, and show that there are several subgroups of minimal size which generate the same equivalence relation among shidku boards as the full group of symmetries under the action of the standard sudokus symmetry group. to demonstrate the practical application of these minimal symmetry groups, we show how they can be used to compute equivalence classes of group actions on graphs.
dissipative quantum many - body systems are emerging as a powerful tool for the study of nonclassical correlations in quantum technologies such as quantum simulation or quantum metrology.   the theoretical analysis of these systems is significantly more challenging than for equilibrium systems due to the lack of an underlying concept corresponding to the partition function. in this paper,   i disscuss an architecture for the realization of largely arbitrary dissipation channels in the context of dissipative quantum state engineering and discuss the implementation of single - particle and two - particle operators describing the effective effects of coherent interactions with auxiliary particles on the reduced system under consideration. using a specific example of a dissipative heisenberg model, i will analyze the phase transitions in the form of energy transfer between the eigenstates of the system and the vacuum of the electromagnetic field, focusing on the case where the resulting effective dynamics is purely dissipative and coherent dynamics is entirely absent.
the term patience sorting is used to describe a card sorting algorithm that uses the schensted insertion algorithm for interposing values into the rows of a young tableau.   the algorithm is derived from the original work by a.s.c. ross and c.l.m. mallows ( 1962 ) and is now known as @xcite. in recent work, g. viennot and p. diaconis have used the shadow diagram construction of the algorithm to characterize the set of permutations that avoid the pattern @xmath1 that avoids the barred permutation pattern by using the following pattern avoidance condition : each instance of the restricted form of the generalized permutation patterns must be contained within an instance of one of the general ones.
cross - kerr nonlinearity is considered as a promising tool for quantum computation and non - classical state generation @xcite.   the problem of decoherence is a main practical obstacle to implementations of schemes using kerr and cross - k Kerr nonlinearities. in our work   we show that the modal loss arising from the process of generation of the generated states can be strongly correlated, and that this correlated loss can result in the significantly enhanced robustness of the generation scheme. on a number of examples we show how the correlated loss enhances and creates intermodal correlations and even entanglement, and might lead to generation of entangled states quite different from those generated in the same scheme without loss.
the dearth of cataclysmic variables ( cvs ) between @xmath0 and@xmath1  hr is well known as the cv period gap.   clemens et al. in a recent paper they propose an alternative theory for the formation of the gap, based on a proposed revision of the mass  radius relation for the lower main sequence. using colour  magnitude diagrams of nearby stars, they show that this revision produces a pair of period ` spikes'at 3.4  hr and 2.0  hr, and claim that this reproduces the observed gap. here   we take issue with this interpretation, and show that it is unlikely to be the only possible explanation. instead, we derive the condition for a mass   radius relation to produce a gap, and point out that this is not satisfied by any thermal  equilibrium mass  radii relation. finally we briefly consider the argument by verbunt ( 1997 ) questioning the reality of the period gap through roche geometry.
the thermal sunyaev zeldovich effect ( sze ) is an integrated effect from the time of last scattering to the present era, and as such the sze signal suffers from projection effects due to other objects along the line of sight.   this introduces non - linear complications to our signal processing efforts, and makes it impossible to conclusively determine the best method by analytic means alone. in this paper  , we test and compare three promising filtering techniques : discrete wavelets, continuous waveslets, and fourier methods. these are applied to mock sz maps for several different survey strategies, and results for the different strategies and filters are computed. using simulated data from the sza, apex - sz, the south pole telescope ( spt ) and the atacama cosmology telescope ( actangelica / act / act.html ), we find that the fourier method is the best filter for the m2-weighted sze maps, with a sensitivity of 100% and a robustness of 0.9% compared to the discrete wavelet and continuous wavelet methods, respectively.
the coulomb glory phenomenon is a prominent maximum of the differential cross section ( dcs ) in the backward direction at a certain energy of the incident particle, provided the interaction with a target is represented by the electrostatic attraction of the nucleus ( partly ) screened by atomic electrons.   the present paper examines the coulomomb glory in collisions of antiprotons with he-, ne-, ni - like, bare, and neutral uranium ions. besides the screening potential due to atomic electrons, the vacuum polarization potential is taken into account. for the neutral atom,   both polarization and inelastic processes can be significant. in the case of the he- or ne- like uranium ions, however, only the polarization of the atomic electrons by the antiproton is significant. for all the other ions, the polarization effect is small.
we propose a scheme to adiabatically transfer an electron from the left end to the right end of a three dot chain using the ground state of the system.   this scheme is a copy of the frequency chirping method  @xcite, which is used in quantum optics to transfer the population of a 3-level atom of the lambda configuration via coherent tunneling via adsiabatic passage ( ctap ) following @xcite. by varying the gate voltages, one can achieve long - range quantum state transfer ( qst ) from one end of the chain to the other by slowly varying the external gate voltage applied on the two external dots ( sender and receiver ). here  , we introduce a simple tight - binding chain with uniform nearest - neighbor hopping integral @xmath4 as a quantum data bus for long - ranges quantum transport through the proposed scheme. at the end of it,   the quantum information bus is connected to the quantum server by a single quantum dot ( qd ) with a single qubit.
scale symmetry has been an interesting subject both in formal quantum field theory and in particle physics phenomenology.   the most important example is the scale invariance ( weyl invariance or conformal invariance ) in string theory, which is nothing but 2-dimensional quantum field theories for the string world sheet in target spacetime of spacetime dimensionality. however, implementing scale symmetry to particle physics has not been so successful compared with string theory for various reasons. since scale symmetry is spontaneously broken by some nonzero values of dimensionful order parameters due to some nonperturbative dynamics, there would appear massless nambu - goldstone ( ng ) boson, often called dilaton related to dilatation symmetry. if scale symmetry were not anomalously broken by quantum effects, dilaton could be exactly massless. here  , we show that dilaton can be light enough to use the nonlinear realization of scale symmetry with built - in quantum scale anomaly.
the robustness and resilience of networks have been extensively investigated over the past decade.   however, the controllability methods for complex networks that can robustly manage structural changes have not been developed. here  , we introduce the concept of structurally robust control of complex networks using the minimum dominating set ( mds ) model. to provide a concrete example, we study the minimum number of driver nodes needed to control the entire network against arbitrary single or multiple edge failures. in our results, we show that the robust configuration of a scale - free network with minimum degree @xmath3 requires the same order of drivers as the non - robust configuration. by comparing the size of the mds in the two configurations, we find that the smallest mds is the one that is most robust under all conditions. moreover, we demonstrate that the minimum degree@xmath4 in a network plays an important role in network controllable and significantly affects the sizeof the md.. in particular, the order of the driver nodes changes if the minimum degrees changes, unveiling the complexity of the network.
molecular dynamics ( md ) simulations of bulk hydrocarbons and water in the bulk phase and under confinement in porous media have been performed to investigate the nmr relaxation and diffusion of crude - oils and polymers confined in organic nano - pores.   the results of the simulations are compared with those of nmr measurements of the same fluids, and the results show that the md simulations can be used to distinguish intramolecular from intermolecules in the relaxation of bulk oil and water at the @xmath10  ns time scale, without any adjustable parameters in the interpretation of the simulation data. using traditional hard - sphere models,   these simulations are used to separate the slow internal dynamics related to viscosity from the fast internal motions related to rotation of the entire macromolecule, which are typically considered as the relaxation mechanisms for macromoles such as @xcite.
the casimir effect in curved spacetime has been studied extensively in the literature of quantum gravity and string theory.   it is believed that the properties of the vacuum state are apparently dependent on the geometry of the background spacetime. in this paper   we extend the analysis of the casimir force and energy for a casimir apparatus consisting of two ideal conducting parallel plates in the weak field limit of the kerr and the horava - lifshitz spacetimes using the metric obtained in the previous section by solving the klein - gordon equation in terms of the parameters of the general weak gravitational field. to find the mode frequencies inside the apparatus under the influence of both dirichlet and neumann boundary conditions for the scalar field, we use the same method but with an interesting property of the fermi spacetime where the electromagnetic field is present inside the plates.
abstractap / bp stars are chemically peculiar stars in which relatively strong magnetic fields have been measured.   they are early a and late b stars, ranging from 8000 to 15000  k in effective temperature, in which large abundance anomalies have been found. as the main difference between them is the presence of magnetism, the understanding of the formation and evolution of the chemical composition in ap stars may yield a new insight into the structure of the magnetic fields. here   i briefly describe the main physical processes that lead to ( or inhibit ) diffusion in stars, starting first with a general description of the components of the stellar plasma, followed by a more specific discussion of diffusion in the absence of magnetic fields.the most important factors that determine the amplitude and sign of the diffusion coefficient @xmath6 are the net effect of the inward gravitational acceleration and the outward radiation acceleration, both of which are strongly dependent on the ionization state and the atomic properties of the species. for each of these factors,   the relative drift of elements with respect to each other is determined by the combined effects of gravity, radiation pressure and convection ( or mixing ). when the radiative acceleration is low, the species will levitate,
we find an excited but stable state with supercurrents, containing flow and counter flow in the layers, even without the presence of an external magnetic field.   this is a skyrmion state found to exist in a layered superconductor described by a two - component order parameter ( op ) that gives rise to an energy gap above the homogeneous state. here   we derive the op and the local magnetic field associated to the skyr mion state from the _ first order equations _ ( foe ) of the ginzburg - landau ( gl ) variational equations, which determine the order parameter and the vector potential associated to topological excitations. using the foe we obtain the topological solutions of the seiberg - witten equations of the two - components of the gl theory, applied to a stack of layers and without the absence of an applied magnetic field.see research article http://www.biomedcentral.com/1471-2148/1741-1.
we study the effects of an added stochastic term in chirikov s standard map on the phase space of eqs.   ( )([eq : g ), a two - dimensional area - preserving map on a cylinder given by @xmath0 given by@xmath1, and the sinusoidal form of the force given by "@xmath7 ). using kam theory, we show that the dynamics of the standard map can be characterized as either  resonant _ or  non resonant_ regions, those around where contractible circles, often referred to as  secondary circles or  islands , arise alongside chaotic orbits. for moderate values of @x Math6,   these effects are most pronounced near the low - order resonances, or those with small coefficients of variation. when @xMath11 is " sufficiently irrational ", however, the existence of such circles is not affected by the addition of a stochastic term.
quantized vortices are the characteristic excitations of a superfluid and they play an important role in superfluid dynamics.   vortex dynamics has been one of the major focuses of bose - einstein condensate ( bec ) research for many years. in this paper, we present an experimental study of periodic vortex shedding from a moving repulsive gaussian laser beam in a highly oblate bec. when the optical obstacle is penetrable ( i.e., the potential barrier height @xmath4 of the laser beam is smaller than the chemical potential@xmath5 of the condensates ), vortex dipoles are periodically shed from the moving obstacle.    furthermore, we find that the vortex shedding frequency linearly increases with the obstacle velocity as it exceeds a critical velocity. to test the stability of the generated vortex dipole, we demonstrate that a single vortex dipolar can be deterministically generated by applying a short linear sweep of a penetrability laser beam.
we investigate the effects of a strong magnetic field on the propagation of neutrinos in magnetized vacuum and charged plasma.   we find that the main contribution to the neutrino energy is linear in the field, independent of the chemical potential, and that it is of the same order as the largest terms found in the weak - field case for the charged - medium. this new result can turn magnetic - field effects relevant for cosmology.
the recent measurements of the wilkinson microwave anisotropy probe ( wmap ) satellite @xcite on the cosmic microwave background radiation ( cmbr ) have shown that the matter abundance in the universe is @xmath2.   the most natural solution to the strong problem ( i.e. the apparent absence of a strong violation in strong interactions implied by the experimental bound on the electric dipole moment of the neutron ) is the one provided by a peccei - quinn symmetry@xcite, which carries qcd anomalies and is spontaneously broken at the so - called axion decay constant or simply pq scale. here  , we examine the possibility that the axions are constituents of cold dark matter ( cdm ). using the minimal supersymmetric standard model ( mssm ) as a basic frame for discussing susy cdm, we find that the lightest neutralino, the axino, and the gravitino can be considered as constituents of cdm because they are the strongest non - relativistic particles out of a number of candidate particles from which cdm can be made.
the hubble constant @xmath0 is an indicator of the global expansion of the universe.   it is generally assumed that the cosmological principle dictates that the universe is isotropic and homogeneous, but observations have indicated that there exists an inhomogeneous matter distribution in the local universe on scale up to @x Math1 mpc, such as matter clumps, voids, filaments, etc., which may cause a deviation of the local hubble expansion from the global one. here  , we present a new model of the lensing model of qso0957 + 561a, b based on the cepheid variables and the globular cluster luminosity function in some nearby galaxies, which yields a large value of @x math0 ranging from 69 to 87 km s@xmath15 mpc at redshift of 1.41. this value is consistent with unity, indicative of a very minor effect of local matter clump and voids on the expansion of our universe.
the molecular cloud cores are the parent clouds for the clusters of proto - stellar cores.   the dense cores are expected to undergo gravitational collapse evolving towards singular points and designated as proto - stars. in this paper  , we will discuss the theoretical aspects explaining the formation of low - mass condensations ( lmcs ) within the cores. since the molecular Cloud cores are characterized by subsonic levels of internal turbulence, small rotational velocity gradients, and subsonate infall motions, the turbulence alone can not be responsible for the formation or evolution of lmc inside the cores ; therefore, the associated thermal pressure in the cores dominates the turbulent component by a factor of several. here, we focus on the effect of short - wavelength waves on the density - profile of the cores with cylindrical shape and appropriate decreasing density-profile. according to the results obtained from the spitzer from molecular cores to planet - forming discs ( c2d ) project,   at least two thirds of 32 isolated star - forming cores, which were studied in the taurus molecular cloud  1 in the regime of@xmath2 and @xmath3, are the evidence of forming multiple stars.. clearly
lcio is a new persistency framework for the international linear collider community.   lcio defines a data model, a user interface ( api ) and a file format for the simulation and reconstruction stages of the simulation. to that end   we have developed a java, a c++ and a fortran version of the user interface. in order to allow the integration of lCio into currently existing software frameworks   a java or c++ version of its api is needed. as part of the development process   it is important to design the api in a way that hides the actual implementation of the data storage mechanism from the user code. by choosing a simple and lightweight design for the api we will be able to keep the development time to a minimum.
the presence of dust in galaxies represents one of the major obstacles complicating a direct quantification of the star formation activity in local and high redshift galaxies.   absorption by dust grains reddens the spectra at short wavelengths completely modifying the spectral energy distribution of galaxies, and rest - frame uv observations can lead to incomplete and/or biased reconstructions of theStar formation activity and star formation history of galaxies affected by dust absorption, unless proper corrections are applied. here   we show that the use of standard ( i.e. age independent ) methods to correct for dust attenuation can strongly bias our interpretation of uv properties of galaxy evolution explorer ( galex, @xcite ) local and redshift measurements.    we adopt a very simple dust geometry model and extinction law to show that these methods can not be used to properly calibrate the @xmath1 vs. @x Math0 relation to account for the age - independent effect of dust absorption on the uv spectrum of active star - forming galaxies. instead, we propose a new empirical relation based on observable quantities suitable for deriving dust attenuated corrections taking into account the _ age effect_ : the ratio of the current to the mean past
the concept of duality is used to describe the properties of two physical systems that can be mapped onto each other by interchanging the role of position and its canonically conjugate momentum.   if the physical properties of one of the systems are known, those of its dual counterpart can be predicted by applying the set of dualness transformations that accompany the position and momentum interchange and relate the parameters of the two systems. in some special cases, duality maps the system onto itself ; one then speaks of self - duality. here   we will focus on the case of josephson junctions embedded in an electromagnetic environment, where the duality associated with the conjugates of charge and phase degrees of freedom has been employed to study the dissipative dynamics of the circuit s dissipative behavior.
we study the possibility of explicit cp violation in the higgs sector of a supersymmetric @xmath0 model.   this model has two@xmath4 symmetries in addition to the standard model ( sm ) gauge symmetry, thus with two additional neutral gauge bosons, and two higgs singlets as well as two higher - order higgs doublets. at the one - loop level  , it is shown that this model may allow explicit cp violations in an explicit way due to radiative corrections. by varying all the relevant parameters within reasonable ranges, to obtain the upper bound on the lightest neutral higgs boson mass, we investigate prospects for discovering the neutral higgens bosons of this model at the large hadron collider at the lhc, by calculating the minimum value of the minimum energy of the x - ray diffraction ( xrd ) data from the xrd spectroscopy experiments performed at the hplc-1/2.1 experiment. using the results of these experiments, we find that the minimum energies of the y = 0.5  kcal / mol and y = 1.0  kcal | mol for the q = 2.3
in the last few years a new generation of models for the chemical evolution of the galaxy has started to appear, in which also the dynamics of the system is taken into account.   these models are quite successful in accounting for the large scale - long term phenomena taking place in the galaxy, and reproduce its major observed features, such as the age - metallicity relation and the g - dwarf distribution in the solar neighbourhood, the elemental and isotopic abundances and ratios, the present star formation rate, gas and total mass densities. to avoid misleading conclusions,   it is however necessary to test the models by comparing their predictions not only with the observational constraints derived for the solar neighbourhoods but also with the data relative to other galactic regions.. the aim of this presentation is then to review the current state of _ standard _ models for each of these parameters, with particular emphasis on the effect of gas accretion on the absolute value and the radial distribution of the element abundances.
the study of galaxy evolution has been connected to that of larger structure formation.   the link between halo mass and star formation, determined by large scale environmental effects, might explain observations such as the butcher - oemler @xcite effect. in order to understand the environmental causes that might trigger intense star - formation in the local universe, such as that observed at high redshifts for lyman break galaxies, we explore two regimes : large - scale, to study the connection between h Halo mass and high star formation rates ( sfrs ) ; and small scale, calculating merger rates. at large scales  , a galaxy s sfr may be connected to how the galaxy accretes gas from its large- and small - scale environment, which depends on the halo masses.    smaller scale environmental factors, from nearby galaxies, may induce star formation from interactions and eventual mergers.. these processes are discussed in this review.
the accuracy of monte carlo glauber ( mcg ) models for describing minimum - bias multiplicity frequency distribution data from the rhic experiment is re - examined using updated density and multipliciity production model parameters and a sensitive power - law inspired representation introduced by trainor and prindle ( tp )  @xcite.   the results show that the accuracy of the mcg model for describing the initial collision geometry is limited by large uncertainties in the estimated number of binary collisions which is used as a scaling variable. to address these uncertainties we use the power - Law analysis method proposed by tp  . the centrality analysis method exploits the approximate power -Law dependence of the multiplicity frequencies distribution data for minimum - biased collisions and uses proton - proton multiplicity production data to constrain the peripheral collision end - point of the @xmath6 distribution. with the help of this method   we demonstrate that the uncertainties in centrality determination and mcg geometry measures can be significantly reduced, particularly in the peripheral region.
the interacting galaxy arp  299 ( mrk  171, ic  694+ngc  3690 ) is a mid - infrared ( mir ) luminous galaxy with two bright visible - light sources in its nuclear region.   we have obtained high - angular resolution long - slit spectroscopy of the two nuclei of this galaxy using canaricam ( cc ) on the 10.4 m gran telescopio canarias ( gtc ) and use these observations to shed light on the processes giving rise to the deeply nuclear embedded emission in both the eastern and western parts of the galaxy. for the nucleus of the eastern component,   the observed deep nuclear emission is due to intense star formation ( sf ) activity across the two galaxies, but there is also evidence of obscured active galactic nucleus ( agn ) activity in the galaxy nuclei as well as a hot dust continuum associated with an obscured agn that contributes substantially to the nuclear infrared emission.
the properties of the kaons and antikaons in the nuclear medium have been the object of numerous investigations since the possibility of the existence of a kaon condensed phase in dense nuclear matter was pointed out @xcite.   most of the recent theoretical works start from chiral lagrangians that reproduce the free space scattering properties which, in the case of @xmath8 scattering, are dominated by the presence of an isospin zero resonance, the@xmath6.. however, it has been shown recently that a self - consistent calculation of the @x Math0 self - energy leaves the position of the resonance unchanged, due to a compensation of the repulsive @x math6 shift with the attraction felt by the @Xmath0 meson. here   we investigate the importance of other medium modifications of the particles participating in building up the @ xmath5 interaction using the model of ref. @xcite, which includes pauli blocking on the intermediate nucleon states and the dressing of the pions in the #16, #17 and #18 intermediate states, which couple strongly to the #18 state. for the latter,   the effect of one- and two - nucle
the theory of exceptional orthogonal polynomials is a new approach to the spectral problems for second order linear differential operators with polynomial eigenfunctions.   it is related to the theory of sturm - liouville problems in that the sequence of exceptional poynomials does not require to contain a polynometric of every degree, and as a consequence new differential operators exist, with _ rational _ rather than polynomatic coefficients. here   we present an extension of this theory to the case of a probability measure supported on an infinite subset of the real line by a nonnegative number @xmath0. using the discrete darboux transformation of the corresponding symmetric tridiagonal ( jacobi ) matrices using the lu and ul factorizations and commuting them @xcite, we show that the family of exceptional families of orthogonality is dense in the corresponding weighted space and constitutes an orthogonsular polynutation system.
the advent of multimedia dominated traffic poses extra - ordinary constraints on data rates, latency and above all spectral efficiency.   the role played by multiple antenna combining in mitigating interference by means of zero forcing ( zf ) beamforming is well established. over the last few years  , the combination of multiple - antenna approaches together with the concept of cooperation among interfering wireless devices was explored, showing strong promise. however, the benefits of multiple antenna transmit cooperation go at the expense of requiring channel state information ( csi ) sharing at the interfering transmitting devices ( txs ). in this paper, we challenge the common view that interfering txs engaging in a cooperative scheme  can _ or  should  share global ( network - wide ) csi. instead, we formulate the problem of a suitable csi dissemination policy across transmitting devices while maintaining performance close to the full csit sharing scenario.. we report a couple of findings revealing how the need for csit Sharing can be alleviated by exploiting specific antenna configurations or decay property of signal strength versus distance, hence making tx cooperation distributed and scalable.
lanthanum manganite ( lamno@xmath0 ) is a distorted perovskite material whose electronic and magnetic properties have potential technological use in a variety of applications such as pseudo - capacitors, batteries, and spintronics.   the onset of colossal magnetoresistance ( cmr ) that can appear upon application of a large hydrostatic pressure @xcite is of particular interest because it induces a phase separated state characterized by the coexistence of different magnetic and structural domains. in this paper, we show that the pressure needed to obtain a ferromagnetic ( fm ) half - metallic state is reduced by an order of magnitude when the pressure is applied along a single axis ( uniaxial ). using dft calculations,   we also demonstrate that the mechanism associated with the insulator - to - metal ( imt ), structural, and magnetic phase transitions observed in this system are mainly controlled by a particular phonon - type jahn - teller ( jt ) mode.
the bus is one of the few public transportation that get the least attention from people due to some reason presented in the early survey.   the aim of this research is to find the optimal location for bus stops that will be located relatively near to the residential area, and the shortest route for the newly discovered bus stop location in this research. a large portion of west jakarta have been chosen as the designated area for this experiment where the houses serve as the main data source. using mean shift algorithm implemented in python version 2.7.11,   we apply clustering algorithm to estimate the optimal locations of the bus stops. according to the results of this experiment, the most important reason for not using the bus is the bus stop is because it is too far away from the residence ( 63% ), the other reasons are " there are no bus stops nearby my residence" with 27%, and just 10% of the respondent felt awfully uncomfortable with the bus condition ( 10% ).
the effective opening of a gap in the conical dirac - like low - energy electronic structure of graphene is often reported in terms of the massive dirac gap model, which predicts a parabolic behavior for both conduction and valence bands with an effective mass proportional to the band gap.   however, the actual experimental band dispersion of supported graphene layers shows many inconsistencies with this model, pointing towards different mechanisms of gap opening. here  , we review the angle - resolved photoemission spectroscopy ( arpes ) data of some epitaxially grown graphene samples, where a spectral anomaly at the dirac point was shown to be associated with the signature of plasmaronic subbands rather than with a simple gap opening, and discuss the implications of these findings for the massive gap model.
we study the effect of the klein - nishina ( kn ) scattering on the high - energy afterglow emission of fermi lat bursts.   we find that the kn scattering affects the electron distribution in the forward shock in @xmath6 2 and the compton parameters for the electrons producing the extended high - energies are affected by the synchrotron self - inverse compton scattering from the reverse shock, which is consistent with the proposed hadronic cascade emission model for the extended emission of grb941017.
the spin - dependent one - body potential in isospin - asymmetric nuclear matter ( ianm ) is investigated by means of the dirac - brueckner - hartree - fock ( dbhf ) method.   the results are compared with those of a previous calculation of spin - polarized pure neutron matter ( nm ) using the bonn b potential, which is used to calculate the spin degrees of freedom of symmetric n - type matter ( snm ). within the latter, the single - particle potentials for upward and downward polarized nucleons are separated by a gradient between the two - nucleon potentials, which can be described as a spin - independent nuclear optical potential, defined in perfect formal analogy with the lane potential for the isospinal degree of freedom in isospecificuclear matter. here  , we show that the splitting of the one -body potential in snm is not only due to the existence of a negative energy dirac state, but also to the presence of a self - energy correction to the nucleon propagator, which leads to an intrinsic density - dependent interaction between the nucleons and the nuclear medium. at low densities,
the transition between plateaux in the integer quantum hall effect ( iqhe ) is a quantum critical phenomenon, which was predicted theoretically and observed experimentally a few decades ago.   it is usually modelled theoretically by noninteracting particles in two dimensions ( 2d ), in a perpendicular magnetic field and a random potential. despite the apparent simplicity of this conceptual setup  , it turns out to be very difficult to derive analytically the critical exponents of this transition. in this paper, we propose a treatment of the original chalker - coddington ( cc ) model based on the lattice path integral. since the corresponding statistical model involves paths which may pass through a given edge infinitely many times, the number of configurations per unit surface is infinite, and the model is not directly tractable by exact - solution methods such as yang - baxter integrability and conformal field theory ( cft ), we introduce a _ truncation procedure _, leading to a series of finite statistical models, and focus on the first order of truncation. for values @xmath0 with loop fugacity, we obtain four critical branches in the phase diagram of this loop model : two of these regimes correspond to a
the present time is one ripe for discovery in the quest for physics beyond the standard model and for the nature of dark matter.   a remarkable convergence of experimental searches for astrophysical and for laboratory signatures from dark matter is taking place at the same time as the large hadron collider ( lhc ) is rapidly probing the parameter space of theories beyond - the - standard model associated to particle dark matter candidates. here  , we show that even in a very limited such slice of the supersymmetric parameter space, there exists a very high degree of  complementarity  between direct and indirect searches for dark matter and the current results on searches for supersymmetry with the atlas and cms detectors at the lhC. by " complementarity "   we mean that relevant, viable parameter space regions exist that are excluded by each one of the mentioned search techniques but not by the others. while further experimental data are needed to confirm or reject claims of discovery, conservatively it is at present at least possible to draw exclusion regions on the relevant theory parameter space. in this study, we start in the first part of the analysis by focusing on a very special corner of the weak - scale supers asymmetric parameter
the first gravitational wave ( gw ) event, gw150914, was detected by the ligo collaboration on 2015 september 14 at 09:50:45 utc.   the trigger was determined to be consistent with a waveform predicted by general relativity from the inspiral and merger of two neutron stars ( ns - ns ) or two black holes ( bh - bh ). in this paper, we calculate the expected high - energy gamma - ray emission produced by the blast waves driven by the wide - angle, mildly - relativistic outflows that could be detected by future ground - based imaging atmospheric cherenkov telescopes ( iacts ), such as the planned cherenov telescope array ( cta ). for the small - angle jets, we find that the self inverse - compton ( ic ) emission from the superparamagnetic outflow is about @xmath2 with an opening angle of ~1.5, which is similar to the case of the short gamma -ray burst ( grb ) possibly associated with the first gw event gw 150914. for those with a wider opening angle, the ic emission is about@xmath3 with anopening angle
supersymmetry is the most promising extension of the standard model.   the elegance of the theory and the simplifications that introduces is of great importance however supersymmetry must be broken in our four dimensional world. in this paper   we study a 4 dimensional n=1 supersymmetric model with a toroidal compact dimension, in topology @xmath3. for some values of the couplings and of the masses, interesting phenomena occur. particularly it is found that in some cases when the volume of the compact space is small supersuum breaking is not broken and when the compact radius exceeds a critical value, supers asymmetry breaks dynamically. also other terms have a curious but worthy of mentioning effect. for these terms   there is a cosmological implication of this case which resembles first order Cosmological phase transitions in the early universe.
the oscillation quenching in many cases leads to undesirable situations.   owing to the fatal consequences due to oscillation suppression, interesting efforts have been undertaken to retrieve / resurrect oscillations of the system @xcite. in this article  , we demonstrate that the problem can be well resolved by providing a suitable feedback in the system. with the aid of numerical and analytical studies,   we show both numerically and analytically that the addition of feedback destabilizes the stable attractors which results in a wiping out of the oscillationquenching and inducing a resurrection of oscillations. in addition, by considering a rather general system, by showing the above destabilizing nature over the amplitude death ( ad ) state, we prove that the method proposed here can be given more easily under different contexts such as in deep brain simulation.
microscopic classical black hole ( bh ) production in transplanckian particle collisions is one of the most exciting possible experimental signatures of large extra dimensions scenarios of tev - scale gravity.   however, thorough theoretical understanding of this process is still lacking. here   i present arguments suggesting that classical gravity description of microscopic bh production may be inadequate. by considering the classical gravity analysis of @xcite, which makes more precise the intuitive picture described above, i show that for impact parameters of the order of the corresponding schwarzschild radius, the collision spacetime contains a closed trapped surface ( cts ). from this fact,   bh formation follows by the singularity theorems of classical general relativity and the cosmic censorship conjecture. to test this intuition, i perform two validity checks : 1 ) field strengths have to be small ; 2 ) the number of field quanta has to be large.the first check is based on the requirement that curvature should be @xmath3 ( in planck units ). as i have shown in @xaite, this condition is violated in the collision space of the collision of two fast point particles in a grazing collision in a region relevant for the
the estimation of sparse low - rank matrices has been studied and used for various applications such as covariance matrix estimation, subspace clustering, biclustering, sparse reduced rank regression, graph denoising and link prediction, image classification and hyperspectral unmixing.   the use of non - convex regularizers ( penalty functions ), however, generally leads to non-convex optimization problems. in this paper  , we propose to solve the improved sparse high - rank ( islr ) formulation by using parameterized non - concave penalty functions, which aid in ensuring the strict convexity of the proposed objective function. a single variable - splitting algorithm based on augmented lagrangian monte carlo approximation ( admm )   is also proposed to estimate the islr problem.
the nuclear incompressibility @xmath0 is related to the curvature of the energy per particle in symmetric nuclear matter around the minimum at the saturation point.   the question about the proper value of this quantity is still open, and the model dependence of it amounts to a difference of the order of 10 - 20% among the values obtained within different theoretical models. here  , we discuss the progress of the relativistic mean field model ( rmf ) calculations on the same footing as the skyrme and gogny energy functionals, and compare them with the results of the previous non - relativismic calculations.
type ia supernovae are among the strongest explosions observed by astronomers.   their near - uniform and easily calibrated light - curves have allowed astronomers to use them as probes into the universe and the nature of cosmology. however, despite their extreme importance, we still do not understand the details of their explosion mechanism nor the exact nature of their progenitor. in this paper  , we study the progenitors of these chandrasekhar - massed explosions using population synthesis studies of binary mergers, hydrodynamical models of mergers and radiation - hydrodynamicics calculations. based on these studies,   we find that the most common type ia progeniting event is a double degenerate merger between a white dwarf and a star with a mass above the chandrashekhar limit. comparing these predictions with observations   allows us to make definitive observational predictions for the single - degenerate scenario.
next - to - leading order calculations of qcd processes at the cern large hardon collider are presented.   the results are obtained in the framework of helac - nlo, which is a new tool for the analysis of lhc data from the hadron - hadron collider at cern and is based on the helac phegas leading - order event generator for all partons level, which has been extensively used and tested in phenomenological studies. using this generator,   several @xmath10 processes have been calculated at next - to-leading order qcd, including jet production via weak - boson fusion, qcd - mediated process @xcite, and finally the first @x Math19 process @x maths20@xcite.. the integration over the fractions of the initial partons is optimized with the help of the following optimization : ( 1 ) the number of particles in the final states is well separated by a factor of 2.5 ; ( 2 ) the size of the final state is optimized by an order of magnitude ; ( 3 ) the total number of jets is optimized as a function of the fraction of the first partons ; ( 4 ) the
the steady free - convective flow and mass transfer of an incompressible, viscous and electrically conducting fluid past a flat surface in the presence of a uniform transverse magnetic field is studied.   the boundary layer equations are transformed by a similarity transformation into a system of non - linear ordinary differential equations and which are solved numerically by using the finite difference technique. for various values of the magnetic parameter, the hall parameter and the relative effect of chemical diffusion on thermal diffusion parameters, the results are given for the velocity distribution and the coefficients of skin - friction along and transverse to the direction of motion of the stretching surface. at the same time, the rate of heat transfer at the stretching sheet is computed for different values of magnetic and hall parameters.
large - distance modifications of gravity give rise to a conceptually new approach to the cosmological constant problem @xcite.   the dgp model is a covariant theory of the large - distance modification of gravity that is experimentally testable. in this model,   a single graviton lives in infinite - volume five - dimensional space - time and behaves as a massive 4d spin-2 state with five longitudinal polarizations. for small non - abelian gauge fields introduced by hand, the nonlinear amplitudes of the perturbation expansion become strong at a scale @xmath1, where the gauge - coupling constant is a gauge - coupled constant. if mass is prescribed by hand ( i.e., without using the higgs mechanism ), then the weak - field approximation breaks down at a size that is only as big as @x Math10, which is an artifact of the ill - defined perturbative expansion. here   we show that the breakdown can be explained by the existence of gauge - dependent terms in the graviton propagator that contain products of the structure  with similar structures or with the flat space metric. these terms do not manifest themselves in physical ampl
we have spent the past 2 years compiling a large sample of high redshift ( @xmath1 ) galaxies, selected in a consistent manner over a number of relatively large fields.   our aim is to obtain @x Math6 redshifts per field in each of 56 fields, each of size 160 square arc minutes or greater. for this purpose, we have used a combination of the well - established redshift selection function for our particular color selection criteria, and the results of our spectroscopic follow  up, which have resulted in a somewhat modified color  selection window as compared to the purely theoretical one which was used originally. at the time of this writing ( december 1997 ),   we have collected a total of about 0.25 square degrees of data from the palomar 5 m telescope, and most of the data are being analyzed using the low resolution imaging spectrograph ( lris ) on the w.m. keck telescopes. by the end of 1998, we anticipate that the present survey will reach completion.
costas loop is a classical phase - locked loop ( pll ) based circuit for carrier recovery and signal demodulation.   various pll based circuits are widely used in modern telecommunications, computer architectures, electromechanical systems and wireless communication. when the pll is initially out of lock, two different types of acquisition processes can occur, either the so - called lock - in process or theSo - called pull-in process.    the first of those is a fast process, i.e. the acquisition takes place within at most one beat note of the difference between reference frequency and initial vco ( voltage controlled oscillator ) frequency. with the advent of qpsk ( quadrature phase shift keying )   this costas loop was extended to demodulate qps k+ signals as well. here   the authors present a new method for the derivation of the acquisition parameters of the costas loops. from the natural frequency and damping factor of the Pll  , the authors have derived similar expressions for all relevant acquisition parameters that can be used to determine the lock - In and pull - In ranges, and to estimate the duration of the corresponding processes. 	 the obtained
cdse / cds core / thick shell nanocrystals ( ncs ) with a thick shell @xcite exhibit superior optical properties than any other nc hetero - structures prepared up to now.   the photoluminescence is never completely quenched in these ncs and the blinking is almost completely suppressed at low temperatures, whereas the non - radiative auger recombination of charged excitons, biexcitons and multi-excitons is almost 100% at room temperature@xcite. as a result  , these nc structures demonstrate a very low threshold for optically pumped lasing.see research article http://www.biomedcentral.com/1471-7007/9/8/17.
the standard model ( sm ) higgs boson is not in the lep exclusion limits, @xmath0 gev, constraints from precision electroweak data,@xmath1 gev   @xcite, and recently also the tevatron limits, which leave about 40 gev window for the standard model higgs Boson.   this window is very interesting and there are several suggestive hints or coincidences related to it : it overlaps with the range of higgs masses in which the standard models can be a consistent theory all the way to the grand unification scale or the planck scale, @Xmath2 gev ; it is predicted to be light, somewhere near 100 gev in simple supersymmetric models, with superpartners near the electroweak scale ; and it corresponds to the largest excess of high - energy higgs like events at lep corresponding to the higgs mass of 98 gev.see research article http://www.biomedcentral.com/1471-7007/1741-7006/9/8/5.
prewetting transition is the continuation off coexistence of the wetting transition on a surface.   experimental observations of these transitions on various systems have been made over the last decade@xcite, but there is no unique interpretation of the various observations. in this letter  , we report the first observation of the coverage map during a prewetting Transition on a cesium metal surface, which includes some frozen disorder. for the first time, we show that the invasion of the surface by a thick film at the transition is found to take place through a creeping motion of the thick film edge. as the thickness of the thin film increases, the coverages of the interface between the two layers of the liquid phase change from a thin to a thick liquid film and the hysteresis of the layer changes from a very slow to a fast one.. the transition reversibility of the hybridization of the two phases is shown to be reversible.
the understanding of fractionalized topological phases in three dimensions ( 3d ) has been an important theme in condensed matter physics.   the present work extends this work by adapting coupled - wire constructions as a tool for the analysis of novel interacting topological physics in 3d. using narrow integer and fractional quantum hall strips as building blocks, the individual building blocks are constructed from coupled quantum wires containing spin - polarized electrons. since each wire can be treated as a luttinger liquid,@xcite, it is possible to construct a system that hosts several fractional topological phase states. here   i demonstrate the potential of this approach by constructing a 2d system that houses several fractions of abelian and/or fractionalic topological states with time - reversal symmetry broken by coupling the building blocks along different directions. at special luther - emery - type points, the low - energy theory of the system can be solved by an exact mapping to non - interacting fermions of fractionally charge.
the cell formation problem is a well - known problem in group technology ( gt ).   it is designed to reduce production costs by grouping machines and parts into manufacturing cells ( production shops ), which are used to set up the manufacturing process in a way that maximizes loading of machines within the cells and minimizes movement of parts from one cell to another. here   we present a new approach for solving this problem using a mixed - integer linear programming model based on a general two - mode clustering formulation with some simplifying assumptions ( e.g. the numbers of clusters by rows and columns are equal ). as an example of input data we will consider the instance of @xcite, which consists of 5 machines and 7 parts.
molecular clouds at high galactic latitude represent an abundant source of gamma - rays due to interactions with cosmic rays @xcite.   we use the _ fermi _ large area telescope ( lat ) to conduct a flux - limited survey of high latitude molecular clouds with the co map. in this paper  , we describe the methods and systematic uncertainties of the survey and report on gamma - ray observations of 9 high latitude, translucent molecular clouds. all clouds have detectable gamma -ray emission consistent with maps of either carbon monoxide ( co ), dark gas, or both. because co self - shields less efficiently and has a lower dissociation energy than, co dissociation occurs deeper into a cloud ( i.e., to higher ), co fails to trace  linearly@xcite between @xmath5 and @x Math6.    we also report the photon index of each cloud, as it reflects the incident cosmic ray spectrum.
tourism and hospitality sectors have witnessed enormous growth in the past century.   given such deep economic footprint, it is highly beneficial to understand customers behavior in order to satisfy the growing demand. here   we address this issue, and explore booking behavior of millions of online customers by mining their travel receipts from january through april, 2015. using rule mining, we found that customers plan further ahead for lower - cost companies which often have special deals and promotions in such cases.
we show that the surface gravity of a killing horizon can be defined as the rate of expansion of space in the direction of the killing frame as viewed by freely falling observers crossing the horizon.   this is analogous to cosmological expansion, but it involves only one spatial direction, and no preferred observer is selected. here   we apply this notion to two - dimensional timelike congruences in a spacetime of any dimension. using the relation [ kappa _   a^2 = -2 _ a, evaluated at the horizon, we find that the 2d surface generated by such a congruence has an induced metric and induced covariant derivative operator, obtained by restricting the derivative to directions in the surface and projecting the levi - civita connection onto the surface. in terms of the surface projector, this is given by _   d_a u^a = h^a_b _ a _ a u^b, which is equivalent to 2d expansion of the flow defined by the geodesics on the killing horizon. for any killing horizon in any spacetime dimension, with the observer moving in any direction, this result is universal.
the metallicity dependence of the period - luminosity ( pl ) relationship between cepheids in the small ( smc ) and the large ( lmc ) magellanic clouds is investigated using self - consistent stellar evolution and linear stability analysis.   the results are compared with the observed pl relationships obtained from the hst, hipparcos and the micro - lensing experiments, which have recently been reanalysed using high - quality cepheid data collected by the eros and macho groups. for the smc and lmc,   both the physical and the theoretical results show a significant metallicitic effect on the pl relationship, although for similar mass and metallivity ranges. at the same time, the existence of a pure evolutionary effect on this relation is not supported by the results of the other studies.
virtual knots and virtual links are a generalisation of classical knots and classical links.   they are graphs embedded in a disk @xmath6 such that every vertex is either one valent or four valent. the virtual jones polynomial is a well - known invariant of v - links, i.e. an extension of the jones Polynomial from c - links to v-links.    we present a combinatorial interpretation of the kauffman  khovanov complex for v - link and v - tangle diagrams using cobordisms in the spirit of d.  bar - natan in @xcite. as a result  , we find that there is more than one _ categorification of the Virtual jonespolynomial_ over the virtual links given by v.  manturov ( e.g. one over each of the virtual link diagrams and one over all the virtual tangles ). on the other hand,   there is only one   _ categorization _ over the v - tangles given by m.  Khovanov ( e).we show that this is due to the fact that the virtual tangle diagram with
the structure and kinematics of the broad line region ( blr ) of active galactic nuclei ( agn ) are still unknown.   it is generally accepted that the broad emission lines seen in type 1 agn are the result of the photoionization of gas in the blr, and that we can use this gas to measure the mass of the black hole itself by measuring the time delay between variations in the continuum flux and the response of the emission lines. however, it is impossible to study the structure of the Blr directly because it is on the order of light - days in radius, which renders it spatially unresolvable even in the nearest of galaxies with the largest diffraction - limited telescopes. here  , we use reverberation mapping techniques to investigate the velocity - dependent time lags in the agn emission lines to extract the kinematic details of the bl rms. using these techniques, we find that the red and blue wings of the civ@xmath9 emission line have a mean lag of 3.4 days, which is significantly longer than the civ  mean response time.    we also find that there is a strong correlation between the red / blue wing of the
we present a toy model of a bose   einstein condensate of dilute, weakly interacting gas of bosons, based on the formalism of second quantization.   the system is characterized by a macroscopic occupation number of a single particle state, and the field operators describing the gas atoms ( @xmath6 is the volume of the box in which we consider the gas ) and a suitable hamiltonian :  for the non - condensed fraction. within this formalism  , it is possible to introduce the parametrization [ grossmogorov   pitaevski ], where =1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,37,38,39,40,41,42,43,44
abstractclusters of galaxies have long been observed to contain an over - density of low - luminosity galaxies relative to brighter systems in comparison to the field.   this has led to the idea that the luminosity function of clusters is fundamentally different from the field lf, and that the galaxy formation process changes in different environments ( e.g., binggeli et al. 1988 ; ferguson & bing geli 1994 ). here   we explore the implications of this hypothesis for the observed faint - end luminosity functions of clusters, and how they could be derived from a universal initial galaxy mass function. using data from deep - band b and r photometry of the central region of the cluster abell  0426 ( perseus ) at 77 mpc, we show that a significant fraction of low- and low - mass cluster galaxies were not part of the initial cluster luminosity or mass function but were formed later possibly through the dynamical stripping of higher mass systems due to the removal of mass. by contrast, the bright end of the lfs of groups and clusters can be altered by galaxy evolutionary effects such as merging events, which can result in a steeper power - law and
romanowsky et al.   ( 2003 ) have recently presented dynamical studies of three elliptical galaxies based on the measurement of radial velocities of a large number of planetary nebulae in each of these galaxies, and conclude that the results are in agreement with the predictions of newtonian dynamics at low accelerations, but go beyond existing support of mond, probing the highest acceleration end in the galaxy sequence, higher than what has been probed with rotation curves of spiral galaxies.
the abundance of metals in the interstellar medium ( icm ) of galaxy clusters is determined by the measurement of the width of emission lines due to k and l - shell transitions from highly ionized heavy elements, the most prominent of which is generated by iron at about 6.9 kev.   the x - ray spectra of rich clusters between redshift 0.3 and the present day show that the abundance of iron in the icm is about 1/3 the solar value, suggesting that a significant fraction of the gas has been processed into stars already at intermediate redshift. here   we investigate the metallicity of the ice in the cluster using the asca data from the bepposax satellite on board the heliocatalyst dacri. for each cluster we find that the relative abundance of all the metals in its icm depends strongly upon the energy and the point - spread function of the medium energy concentrator spectrometer, but not on the distance from the center of the cluster to the edge of the universe.    the results are consistent with the idea that the origin of the metal enrichment in the clusters is related to the presence of type ii supernovae ( sn )
non - abelian anyons are quasiparticles with statistics different from bosons or fermions.   they are of great interest due to the possibility of realizing anyons in a physical system and due to their potential for technological applications. by applying the berry phase technique @xcite to the kitaev s honeycomb spin lattice model  , we calculate the evolution associated with an adiabatic exchange of quaiparticles. using exact eigenstates of a 360 spin system,   we obtain a unitary matrix that corresponds to the statistics of the conjectured non-abelian ising anyons. together with the fusion rules of these anyons   this conclusively demonstrates the non - abelsian character of kita ev s model, thereby confirming the conjecturing behavior. also, we present a scheme for creating, transporting and characterizing the anyons that could be used in the proposed physical implementations of the proposed quantum systems  . we provide exact predictions for a physically realistic range of the model s parameters.
we report the rotation of elongated particles composed of isotropic nonabsorbing material in a tem@xmath0 gaussian beam trap, using a plane polarised beam to align the particle with the plane of polarization, a rotating plane polarized beam to rotate the particle at a controlled rate, or a circularly polarised beams to rotate it with constant torque.   we computationally model our experiments, using the _ t:\matrix method  @xcite to calculate the scattering of the trapping beam by the particle, and hence the optical force and torque.the results unambiguously confirm our interpretation of our qualitative and quantitative experimental results. for the first time  , we show that it is possible to measure the optical torque applied to the particle using purely optical means. apart from being of interest for monitoring the torque, it enables the use of this method as a quantitative tool  the rotational equivalent of optical tweezers based force measurement.
recent hydrodynamic simulations of large - scale structure formation in cold dark matter ( cdm ) dominated cosmologies have been able to naturally reproduce the lyman - alpha ( ly@xmath0 ) forest.   these simulations have brought about a paradigm shift in our understanding of the intergalactic medium ( igm ), and have shown that the observed spectrum is described by the density, temperature and velocity of the gas at all points along the line - of - sight, and the absorption lines that make up the forest are caused by extended over - densities, rather than discrete clouds. despite this   there is little direct evidence that the emission lines seen in the simulations are statistically non - voigt, and many absorption lines appear to have remarkably gaussian velocity distributions, especially at lower redshift where blending is less of a problem. on the other hand,   some absorption lines may also have non - gaussian features, which could be attributed to blends of two or more profiles as to an intrinsically non-voigt distribution. in this letter   we develop a method to detect departures from the voig taut profiles of the absorbed absorption lines in the simulated forest spectra, and apply
the theory of swimming in a viscous fluid is based on low reynolds number hydrodynamics.   we study the swimming of a collinear swimmer consisting of little spheres which can move relative to each other and push or pull the head of a flagellum or tail, taken to be a sphere of large radius. using the bilinear theory we employ a dynamic picture in which the forces acting on the individual spheres are decomposed into harmonic direct interactions and actuating forces summing to zero. for the longitudinal model   the swimming is a second order effect due to longitudinal or transverse waves propagating along the tail which couple to motion along the axis via the nonlinearity of hydrodynamic interactions. in numerical calculations   it is possible to obtain explicit results for the two - sphere swimmer with two or three little spheres pushing a big one by using the same equations of motion but with the following modifications : ( 1 ) the size of the head is set to be much smaller than the radius of the big one ; ( 2 ) the head and tail are linked together by nearest neighbor harmonic interactions ; ( 3 ) the swimming speed is proportional to the ratio of the diameter of the small
we study the current - induced spin - transfer torque ( stt ) of defect - free magnetic domain wall ( dw ) in ballistic limit by the first - principles electronic structure calculations.   our results show that the nonadiabatic stt of fe dw has localized form while the out - of - plane stts of co and ni are typical nonlocal oscillating torques. for the ferromagnetic dws ( fe, co and Ni ),   the stt is higher than the adiabatic one which is due to the fact that the local spin of the conduction electron can not follow the local spins of the incident electrons as the width of the dw decreases. however, for the relative narrow dw a nonlocally oscillating torque has been predicted theoretically by several groups@xcite and its quantum origin is similar to the rkky oscillation. on the other hand, we have found that the high - order torque in fe dw is more pronounced than the low - level torque in all the other ferromagnetically related dws.
low - mass x - ray binaries ( lmxbs ) are transient systems, in which a stellar - mass black hole ( bh ) is accreting from its companion star.   they are thought to have evolved from primordial binary systems consisting of a massive star and a low- or intermediate - mass companion. here  , we show that the initial masses of the secondaries in short - period binaries are generally @xmath8, since the bh spins of the two stars increase with accretion of @xcite, and the initial mass of the bhs in these systems is ~1.5 times lower than that of the donor star. for the first time, we propose a new model for the evolution of the primary and secondary in bh l MXbs, based on the cosmological properties of the cno - processed material in xte j1118@xmath7480 from its ultraviolet spectra. using this model, we find that the core - envelope binding energy of the host star is much lower than expected, and that the orbital separation between the donors and secondaries is much smaller than the orbital separations of the present - day binaries. by contrast, the outer envelope
we propose a novel method for numerical simulation of quantum field theories with asymptotic weak - coupling expansions.   the method is based on the stochastic interpretation of schwinger - dyson equations, which are typically much easier to derive than the general form of the coefficients of perturbative series. in the present paper   we show that the method can be used to systematically sample strong - coupling expansion diagrams for non - abelian lattice gauge theories, such as sigma - models with @xmath6 target space, and for monte - carlo - based theories with high-@xmath7 limit, like the aizenman random current representation @xcite. using this method, we find that it is possible to obtain results with precision which are almost identical to those obtained by the conventional diagrammatic montecarlo procedure, and that the simulations can be carried out without the need for detailed knowledge of the structure of the perturbation expansion.
the large hadron collider ( lhc ) has been commissioned and will soon be used to test models of multiparticle production in hadron - hadron collisions up to an energy of 14 tev.   new data on inclusive charged particle distributions from @xmath8 collisions have become available using the heavy ion jet interacting generator ( hijing ) model, which contains both longitudinal field induced soft beam jet multiple jet production and collinear factorized perturbative quantum chromodynamics ( pqcd ) based _ hard _ multiple jet produced for @x Math13 gev / c. the results show that the hijing model provides a simultaneous and consistent explanation of several effects : the inclusive spectra at moderate transverse momentum ; the energy dependence of the central rapidity density ; the two particle correlation functions ; and the degree of violation of koba - nielsen - olesen ( kno ) scaling @xcite up to tevatron energy.
the prediction of effective properties of heterogeneous systems such as porous media and two phase composites is of considerable interest. to optimize the properties of these systems   it is necessary to understand how morphology influences effective properties. in this paper   we describe models which do give a realistic representation of the microstructure observed in many classes of composite materials, and which remain percolative at very low volume fractions.   variational bounds and computer simulation are used to estimate the influence of morphology on diffusive - transport and elastic properties. by qualitatively comparing these morphologies to those observed in physical systems,   the models can be associated with classes of physical composites. for example, a highly porous model can be obtained by generalizing the well - known ios model  @xcite to include the case of arbitrarily thin hollow spheres ( e.g. hollow ceramics and foams fabricated from hollow spheres ). using these models we evaluate bounds on the effective conductivity and elastic moduli of porous rocks, solid foams, membranes and polymer blends based on the 3-point statistical correlation function @xcite.
the cms experiment at the large hadron collider ( lhc ) recently announced that, for standard model ( sm ) with four quark generations ( 4 g ),  the higgs boson in the mass range of 120 to 600 gev is excluded at the 95% c.l.   ( @xcite ). here   we explore the possible lower lying bound states of strong yukawa coupling, and the associated properties. using a new, heavy isospin, we show that the @xmath2 and@xmath3 quarks are in the opposite limit of degenerate under qcd, and that they can be strongly coupled to the stronger @x Math22 scattering domain by breaking down the weak interaction between the two quarks.    we also show that electroweak symmetry breaking ( ewsb ) may be triggered by the strong yUKawa couplings of the 2 and 3 quarks, and discuss the implications of this for the baryon asymmetry of the universe.
super - resolution ( sr ) is a promising technology that is expected to be applied to microscope time series images, satellite photographs, and so on. in this work, we propose a new sr method that employs a compound gaussian markov random field ( mrf ) prior that can simultaneously represent smoothness and edge of image @xcite and utilizes variational bayes to calculate the optimal estimator, posterior mean ( pm ), with respect to the objective function of the peak signal - to - noise ratio ( psnr ).   the proposed method is evaluated by comparing the results of the observed multiple low - resolution grayscale images with those of the sr method. for the hr image,   it is assumed that the number of pixels for each high - resolution image is less than that of the spatially high -resolution image.    the model parameters are modeled as lexicographically stacked vectors. using the kullback - leibler divergence ( kl ) divergence from distribution @xmath0 to distribution@xmath1 as the input parameter, the probabilistic estimates of the pm of the obtained hr image are calculated. according to the kl divergence, the best estimator is found to be
in this talk i am going to discuss on the geometrical property of space generated by the monte carlo simulation of 4d quantum gravity mostly with one u(1 ) gauge field.   the main focus is on the results of the finite size scaling analysis of the phase transition in the lattice 99 and the fractal dimension measured by two independent methods at lattice 98, which have shown that the new phase is continuous and possibly of second order. in the followings   we take our numerical results seriously, and study the consequence mostly on the geometry of space for the case with one U(1)gauge field.
the quantumness of correlations in composed quantum systems is believed to be the resource behind the advantage of protocols developed ( to process and transmit information ) in quantum information theory ( qit ) over its classical counterparts.   one of the main problems in qit is the characterization and quantification of such a resource. here   we present an analytical expression for a symmetric definition of classical correlation and its quantum counterpart  for the so - called two - qubit bell - diagonal states.    we also present explicit examples of classes of states where the asymmetrical quantifiers may be not convenient since different values for the correlations are obtained depending on the measurement process adopted.
turbulence modeling has become an important part of scientific and engineering design process.   it has been shown recently that the turbulence models, derived by application of the chapman - enskog expansion ( ce ) to a _ model _ kinetic ( boltzmann - bgk ) equation written for hydrodynamic modes, are similar to those previously obtained from the wyld ( 1961 ) expansion, applied directly to the navier - stokes equations. in this work  , we reformulate the procedure developed in chen et al ( 2004 ) by taking into account both microscopic and hydrodynamical modes. to achieve this goal, we had to substantially redefine the expansion procedure and, as a result, obtain a qualitatively new class of turbulence models based on the coarse - grained kinetic equation for hydrolysis modes. using the fast microscopic variables, we show that the newly obtained turbulence models are equivalent to the well - known turbulence models derived from the perturbation theory, leading from kinetic equation to the Navier - Stokes equations, if one writes the relaxation time @xmath4 of kinetic theory and represents the temperature@xmath5 and the temperature @x Math6 as @
the spatiotemporal dynamics of a one - dimensional ring of diffusively coupled relaxation oscillators that model a chemical system is investigated.   the local dynamics of individual oscillators are all identical, being described by the generic fitzhugh - nagumo ( fhn ) model which is a phenomenological representation of the mechanism underlying periodic activity in many chemical and biological systems. as interactions between biochemical oscillators through reaction - diffusion mechanism   are thought to be a critical component for living systems, the demonstration of computing via chemical oscillations presents a direct connection between information processing and the process of life.
the pulsar b0919 + 06 was discovered in the second molonglo pulsar survey @xcite.   it has a period of 0.430 s, a period derivative of @xmath4, and a characteristic age of@xmath5 years. over the 30-year span from 1979 to 2009, timing observations of the pulsar at frequencies near 102 or 112 mhz were carried out at the pushchino radio astronomy observatory ( prao ) using a 64-channel radiometer with a channel bandwidth of 20 khz and a time resolution of 2.56 or 1.28 ms. during this time  , 450 individual pulses were summed synchronously with a predicted topocentric pulsar period to produce the mean pulse profile in each 20 kazakhmic channel. after the removal of deterministic pulsar spin - down from the arrival times, all the channel profiles were summed to form an integrated pulse profile for the given observing session. then this integrated profile was cross - correlated with a standard low - noise template to give the topocenter pulse arrival times for each observing session ; the geometrical data set analyzed includes the archival jet propulsion laboratory ( jpl ) data and the
we investigate the general mixings and interactions of @xmath0 + gauge bosons in the spirit of weinberg s effective lagrangian and anomaly cancellation conditions to find a most probable parameters space.   we reivew the most general mixing parameters, including mass and kinetic mixings, in sec. and discuss the interactions with leptons and quarks in sec.we find that the number of@xmath14 is decided by assigning @x Math3 charges to fermions with the requirement that these cancel the gravitational - gauge anomaly in the triangle diagrams. using these results, we calculate the oblique radiative corrections from the similar to holdom @xcite. for the light fermion case,   the model inputting charges yields a constraint on rotation matrix elements and disregards stueckelberg coupling unless the @x maths0 coupling fermium and right - handed neutrinos are involved.. couplings correction from gauge boson mixings is derived which results depend on mixing parameters and fermionic @x math3 charges.    with anomaly - free charge assignments, @xMath0 phenomenology is studied. branching ratio
electrophoresis of charged colloids and polyelectrolytes has been studied theoretically and experimentally for several years.   however, the electrophoretic mobility of electrically neutral polymers in solutions containing mobile ions has not been studied. in this study, we propose a new mechanism for the electromagnetic mobility of nonionic polymers with selective affinity to mobile ions by considering the effects of ion - dipole interactions. because the model for selective affinities is based on assumptions, analytical expressions would not be able to quantify the mobilities. here, we use electrohydrodynamics to analyze the effect of selective affinity on the electramagneticmobility of a porous sphere with radius @xmath5 in electrolyte solutions. using the debye - hckel approximation and weak - field linearization,   we find that the mobility of the sphere is finite under a sufficiently weak electric field. when the polymer is dilute, the mobility is reduced by the concentration polarization of the electric double layer and surface conduction, and the mobility increases by the selectivity of the ions to the polymers.
the galaxy luminosity function ( @xmath10 ) remains at the core of both galaxy evolution and cosmology.   the study of number counts can therefore be used to test world models or to search for evolution during the look - back time. in this paper  , we use data from the hubble deep field ( hdf ) north to test the validity of previous number count studies and to produce a new determination of the faint end of @x Math0 for magnitudes fainter than @x maths1. using surface - brightness fluctuation ( sbf ) measurements, we show that the number count of galaxies as a function of apparent magnitude, @x math0, is not accurate enough to predict the age and metallicity of unresolved stellar populations of nearby galaxies ; however, the sbf signal can provide information about other kinds of undetected and unresolved objects in an image. by comparing the sbfs produced by the stellar population of a galaxy with those of nearby stars for which externally calibrated distances are available, accurate estimates of distances   can be obtained up to@xmath1440 mpc @xcite.
the physical mechanisms to set the mass ratios of binary stars are of fundamental astrophysical importance, since more than half of main - sequence, pre - main sequence, and even protostars having masses comparable to the sun are members of binary systems.   accretion from circumbinary disks of molecular gas and dust ( cbds ) onto the central protostellar binaries has been considered as one of the key physical processes to set these binary mass ratios. in the present paper, we use smoothed particle hydrodynamic simulations to reconstruct the mass and mass ratio of a young class i protostellar binary l1551 ne located northeast of another, brightest protosteller binary L1551 irs 5 in the l15 51 region.. the results show that the mass ratio is significantly changed by accreting gas into the binary through the center of the cbd, which is much smaller than the mass of the central cbd. on the other hand,   the accretion of materials from the surrounding protstellar envelopes is not affected by the accretions of gas from the cbcds onto the binaries.
in recent work on two - baryon systems in lattice qcd, members of the hal - qcd collaboration have extracted short - distance potentials from their simulations.   the method relies on the construction of a bethe - salpeter amplitude or  wave function "  a matrix element of two interpolating fields with the quantum numbers of the baryons involved and is then inserted into a schrdinger equation to deduce the nucleon - nucleon potential that would generate it. here   i use a toy model of two - body scattering with two coupled channels to illustrate how a potential constructed in this way can develop features that reflect the choice of interpolating field, and not the actual dynamics. in particular an admixture of a closed channel can lead to a strong repulsive core in the derived potential that does not correspond to any aspect of the original model.
electronic wave functions in a disordered lattice exhibit an exponentially localized envelope in space  a phenomenon, commonly known as the anderson localization.   the key point in this phenomenon is the dimensionality. within the tight binding approximation,   electronic wave functions are localized for dimensions @xmath0 ( the band center in the off diagonal disorder case is an exception ). for@xmath1 with strong disorder, the wave function decays exponentially. however, in low dimensions, or more specifically, in one dimensional dis ordered lattices even a complete delocalization of electronic states can be seen. here  , we put forward examples of a class of essentially one - dimensional disordered and quasiperiodic lattices where a _ completedelocalization _ of eigenstates can be engineered, and _ absolutely continuous _ bands can be formed in the energy spectrum when an infinite disordered or quasipeperiodic array of two kinds of ` bonds'is side coupled to a single or a cluster of quantum dots ( qd ) from one side at a special set of vertices. in some of the examples cited here, the attachment of the dots form local loops which can be pierced by a constant
the @xmath1 mission has left us a legacy of unidentified @x Math2-ray sources at low and mid - galactic latitudes.   most of the known sources of emission above 100 mev remain unidentified, and most of these appear to be associated with the galaxy. in this study, we use the parkes multibeam receiver to survey the sky for radio pulsations at 20  cm using a tesselation pattern that covers an area of the sky ~8 times that of the swinburne mid and high - latitude data sets from the @x math1 mission.. the results show that there are at least two classes of mid - latitude pulsars that could have been detected by @x maths1 : ( 1 ) pulsars in the gould belt and ( 2 ) millisecond pulsars ( msps ) outside of globular clusters. among the identified pulsars,   many would be radio - quiet, but a good fraction should be detectable as radio pulsars as well.
the reduced - action model of the gravitational @xmath1-matrix at transplanckian energies is improved and complete.   the new model is embedded in three dimensions, so as to be able to describe the motion of the breit - frame during the scattering process. for regular ( uv - safe ) solutions, rescattering corrections are needed in order to achieve self - consistency of motion and metric at higher orders in the eikonal expansion.
grb090102 was detected by the magic - i telescope on january 1@xmath3, 2009 at 02:55:45ut  @xcite.   the prompt emission lasted for about 30s, an x - ray and an optical counterpart were discovered and followed - up by several groups. using spectroscopy, a redshift of @xmath4   was derived, allowing to derive an isotropic energy release of @Xmath5  @xaite. in this study, we analyze the data from the magic telescope under excellent observation conditions and at a very low zenith angle, ensuring a low energy threshold around 30  gev. as the trigger energy threshold depends very sensitively on the telescope zenath angle, only data with z@x Math8 were used here, ensuring an analysis threshold around 20  g ev.    these data cover 5919  s of observation time.see research article http://www.biomedcentral.com/1471-7007/9/49.
super - tev scale black holes have been proposed as a possible end point of stellar evolution.   it is postulated that these black holes could be formed by high energy neutrinos in the interior of a neutron star, which would provide a medium in which they could interact with more nucleons before they evaporate and then grow. here   we discuss the possibility of producing such a black hole at the next generation of super - Tev scale colliders using a new model of electroweak physics based on the theory of planck's theory of gravity where the mass scale associated with gravity is around a tev but appears to be much higher due to the small overlap of the extra dimensional graviton wave function with our standard model brane.
we introduce a general method to extract chosen polarized quark distributions from an arbitrary combination of final state asymmetries.   this new approach is particularly useful in light of the latest generation of existing  and forthcoming  experimental efforts, which allow identification of a large number of final states hadrons. within the framework of the presented formalism  , we quantify the sensitivity, as a function of kinematics, of various hadrons to the light quark flavors. for each of these flavors,   we find that the polarization of the initial state partons is sensitive to the intensity of the current fragmentation region, which is usually regarded as a necessary criterion for quantitative measurements of hadronic reactions.. however, we show that, generally speaking, there is no _ a priori  reason to minimize the effects of target fragmentation on the results of such measurements. using this formalism, we have shown that, independent of the kinetic cutoff, all collinear singularities for sufficiently hard hadrons can
we present a  set of asymptotic measures of the distribution of ergodic components of a  stationary process with infinite excess entropy, a  finite number of output symbols, and a  countably infinite alphabet of hidden states.   we show that these measures are also useful for modeling natural language.
the sunyaev - zeldovich effect ( sz ) can be used to determine the cosmological mass density of a galaxy cluster by combining x - ray and radio observations.   this procedure generally assumes that the cluster gas is spherical, unclumped and isothermal. however, most clusters show departures from these simplistic assumptions with some to a large extent. in this paper  , we study another important phenomenon that can substantially change the temperature structure of a cluster, namely a cooling flow. using single dish observations over a wide range of wavelengths, we show that the sz decrement for the central region of the cluster is due to an inward ` cooling flow'initially arising due to the pressure gradient, which then increases with time. at the same time, the power law of the gravitational collapse is changed, and the cooling flow becomes more inwardly driven as the energy is lost due to radiation faster than it was earlier lost. on the other hand,   the entropy of the core decreases with time, leading to a quasi hydrostatic state around the cluster center. when the cluster mergers, the heating of the infalling gas in the cluster could be reduced to a lower order of magnitude, but the
the large hadron collider ( lhc ) is currently under construction at cern ( geneva ) and will go into operation in 2007.   the interplay between the two machines is a very rich field, of which only very little has been explored so far. to assess the potential physics gain arising from concurrent operation of the l hc and the ilc,   detailed experimental simulations of the experimental capabilities of both machines in different scenarios of physics within and beyond the standard model are needed. here   we review the results of the first working group report  @xcite, which investigated the possible synergy between the lhcs and ilcs in these scenarios.
we perform a systematic analysis of the effects and interplay of low - frequency fluctuations on the decay of the coherent signal in solid - state quantum information processors.   we show that the noise sources are mostly broadband and structured, i.e. the noise spectrum extends to several decades, it is non - monotonic, sometimes a few resonances are present and can be explained by the presence of spurious fluctuators which also show up in the time resolved evolution. as an illustrative case  , we analyze the effects of low- and high - frequency decoherence effects on the behavior of ramsey fringes in charge - phase qubits using a multi - stage approach for the different classes of broadband noise. from the results we derive a road - map to treat broadband noise which allows to obtain reasonable approximations by systematically including only the relevant information on the environment, out of the huge parametrization needed to specify it.
sdb binaries are important to clarify the evolutionary origin of sdb stars because the analysis of light and radial velocity curves can constrain their dimensions and masses.   however, only five suitable systems are known up to now. here   we report the spectra of hs  2333 + 3927, a sdb star and an m dwarf companion, which was observed at the calar alto observatory with the cafos spectrograph at the 2.2 m telescope in order to derive atmospheric parameters by balmer line fitting. using the results of the experiments, we show that the mass of the companion is about 1.5  solar mass ( @xmath12=0.1718023  d ) and the orbital period is about 0.6  d. the radial velocity curve is sinusoidal and the semi - amplitude is @x Math13 km / s and the mass function follows as @x math14  =  0.0128m / s for the companion and @x maths14  means  0% by mass for the main body.
in a peer - to - peer ( p2p ) file sharing network, new peers continually arrive into the network and simultaneously download pieces from a seed or other peers and upload pieces to other peers.   the last few pieces to be downloaded by a peer are often rare in the network, so it usually takes the peer a long time to finish downloading them ; this phenomenon has been referred to as the _ delay in endgame mode _   @xcite ( or  last piece problem _ ). in this paper  , we determine what parameter values yield stability for a simple model of a p2c file sharing system that includes a fixed seed and new peers with no pieces at the time of arrival.the main result is to show that the bottleneck for stability is the upload capacity of the seed. if the arrival rate of new peers is greater than the seed upload rate, the mean number of peers in the system converges to infinity almost certainly. when the seeding rate is equal to the incoming arrival rate, however, the system is positive recurrent and the mean size of the network in equilibrium is finite.conclusionsthe results of this paper suggest that the most effective way to achieve stability in a p
recent cosmic microwave background ( cmb ) anisotropy results lend powerful support to the inflationary cosmology as the origin of structure in the universe.   it is now widely expected that cumulative improvements in the cmb data will lead to progressively more accurate estimation of cosmological parameters, with projects funded so far culminating in the _ planck _ satellite mission expected to report results around 2010. given the complex nature of the data, it is necessary to simultaneously fit both for the parameters describing the global cosmology and those describing the'initial perturbations'; they can not be considered separately. here   we study how the data analysis can be performed in two different scenarios : firstly, if one wants only to estimate cosmologic parameters, such as the baryon density and reionization optical depth, and does not care about the underlying inflation model beyond being confident that the description of the initial perturbed states used is adequate. in this case, observers typically use a power - law fit, and the first question is to test whether this kind of fit is accurate enough for present data, and whether it will also be accurate enough to analyze high - precision data like that to be provided by the _
the discovery of millisecond oscillations in the persistent emission and also in thermonuclear x - ray bursts from neutron star low - mass x -ray binaries ( lmxbs ) has opened a new window on the dynamics of accreting neutron stars @xcite.   the time scales of the khz quasiperiodic oscillations found in the persistently emission match those expected from accretion dynamics very close to the neutron star in a region of strong gravity, and the possibility that these oscillations could be used as probes of stronggravity is very intriguing. here  , we describe observations made with the rossi x - rays timing explorer ( rxte ) following the detection of x - Ray bursts from the transient source sax j1750.8 - 2900 from the galactic center during the 2001 outburst of type - i activity at mjd 52000 ( march 2001 ) using the wide field cameras ( wfcs ) and the all - sky monitor ( asm ) on rxterra. among the bursts,   four bursts were detected in a single observation on 4 april 2001 ( mJd 52003 ). for the first time, we report the discovery of
we benchmark four levels of sham density functional theory ( dft ) approximations, following the " jacob s ladder " metaphor of perdew and co - workers  @xcite, by performing accurate quantum monte carlo calculations on the model of the interacting electron gas subject to a central impurity potential.   the proposed system closely relates to an atom in a real material while retaining a simplicity that is amenable to highly accurate solution under a wide range of conditions ( slowly- and rapidly - varying density regions as well as a wide variety of density values ). for each level of dft,   we find that the results obtained for the total and correlation surface energies obtained with spheres are consistent with the latest dmc results for jellium slabs @xcite and other methods, but differ to some extent from the original dmc result from slab geometries  @xxcite.
the @xmath2 spectrum, measured by the atic and pamela collaborations, in the energy range between 20 gev and 1 tev, obtained during the first six months of the fermi mission@xcite, has been interpreted as a signature of dark matter ( dm ) decay or annihilation.   we propose a new model based on a kraichnan - like turbulence in the interstellar medium ( ism ), which is more compatible with the results of the recent release of data from the h.e.s.s. cherenkov telescope, which show that the observed spectrum is compatible with a single power - law with spectral index @x Math5.    this result calls for some revisions of the models we proposed in the same paper, which were based on the assumption of the existence of a kolmogorov - like turbulent region in the ism. using the recently developed dragon  maccione / dragon/ package @xcite to perform a combined maximum likelihood analysis on b / c and antiproton data, we find that the proposed model is not the most adequate to describe the measurements.
the relativistic calculations of the amplitude of the quasielastic nucleon removal reactions @xmath1 and@xmath0 are discussed.   the importance of orthogonalization in the calculations is examined using a modified version of the distorted wave impulse approximation ( nrdwia ) which takes into account the non - orthogonality of the nucleon wave functions needed for the calculation of the reaction amplitude, and the current operators obtained from the free probe - nucleon relativistically calculated amplitude for the one photon exchange model for the @x math3 process.    the results show that the two versions of the amplitudes for the two reactions under consideration suffer from an orthogonsality defect, which is due to the use of wave functions for bound and continuum states, which are solutions of equations containing different hamiltonians ; the bound states are generated from real potentials, while the continuum states are derived from complex energy dependent optical potentials.. the effect of this defect is investigated using a gram - schmidt orthogonaic correction procedure. as a result   it is found that the reactivity of the continuum state is reduced by about 50% compared to the bound state,
we present a model for the formation of strange stars from quark matter in pulsars.   the model is based on the theory of bubble nucleation, with the hadron phase being a free degenerate neutron gas and the quark phase a bag model with only @xmath0 and@xmath1 quarks.. the temperature at which the transformation takes place is estimated to be about 2 - 3 mev, and the time required to form a spherical quark bubble of radius is about 1.5 - 2.5 kcal / mol. as a function of the number of quarks in the bubble, the rate for bubble formation is given by the ratio of the pressure difference between the two phases of the neutron star to the total baryon number inside the bubble ( sec.  = 0.2 ), and it is found that the rate of bubble formation increases with increasing temperature. 			 \label{wcrit}{wcrit}=\label{nucleus }   { nh2}/nh2o^{2}}.   this is consistent with the results of some previous studies, but not with the result of others.
the effective field theory ( eft ) analysis of the nn interaction using chiral symmetry as a constraint has a recent but prolific history.   most theoretical setups are invariably based on a perturbative determination of the chiral potential and the subsequent solution of the scattering problem. however, the theory encounters many problems in the low partial waves and in particular in the @xmath2waves. here   we review the current state of knowledge about the short distance singular character of the one - pion exchange ( ope ) and the two - pions exchange ( tpe ) potentials in the@xmath0 channel which is very special since the scattering length is unnaturally large as compared to the range of the strong interaction, @x Math3.    we show that the single - singlet channel is an ideal place to learn about the size of the most relevant short range corrections to the nh force in the elastic scattering region. for both the ope and tpe potentials,   the results are found to be strongly cutoff dependent when being evaluated at leading order ( lo ), leading order plus a nonderivative counterterm, and the effective range is about twice the experimental value.
we study the scaling of the gap in a number of spin chain models in the lindblad setting.   we find that the gap scales with system size in a way that is independent of the system length. for some systems with bulk dissipation the gap can be constant for some other systems with boundary dissipation, while for other systems it can scale as small or large. to test this hypothesis we have studied the effects of the number of sites at which dissipation acts on the system size and found that the difference between the two conditions is not statistically significant.
the boundary between quantum and classical physics has long been a perplexing issue for physicists.   the prevailing view is that quantum systems tend to interact with their environments and become entangled with them. in this paper   we provide a simple, experimentally accessible scheme that could clearly demonstrate this process. by using entanglement  , we show that the system behaves more and more classically the more it has interacted with the environment. as a result, we find that the total system including the environmental states is properly treated with quantum physics. however, if we are interested only in the quantum subsystem and make measurements only on this, we effectively throw away the information about which environmental states are correlated with which subsystem states. in effect, by throwing away information about the quantum correlations we are left with a system that behaves classically.see research article http://www.biomedcentral.com/1471-7007/1741-7006/9/11/8/1
the formation of dust grains in the interstellar medium ( ism ) of galaxies at high redshift has been the subject of much debate.   recent models of grain formation in evolved low mass stars, from which grains are thought to have been transported to the ism through stellar winds, have been challenged by observations of newly synthesized dust in the supernova ejecta of snr  2003gd ( ngc  628 ), a young, oxygen - rich snr in the smc. here   we show that the observed dust mass in the snr ejecta falls short of the required amounts for the model to explain the observed observed large observed dust masses in the galaxy. using data from the sloan digital sky survey ( sdss ) and the stanimirovic   stani   dwek study of sn  1987a, we estimate that up to 0.02 solar masses of dust have formed within the sn ejecta during the first gyr after the big bang, and that this amount is consistent with the observed far - infrared and sub - mm emission from the same remnant. on the basis of these results, we propose that the origin of the new dust grains is likely to be
we consider the vector - chirality ( vc ) phase and the rung - single ( rs ) phase of the spin-@xmath0 two - leg ladder with four - spin ring exchange model of the haldane integer spin chain @xcite to identify the ground state properties from the view point of the bulk - edge correspondence.   we find that the vc phase is a non - trivial topological insulator, where the local order parameter is not invariant against the symmetry operation which leaves the hamiltonian invariant. in the case of the rs phase,   the monte carlo theory is used to characterize the ground states of the rms phase by means of the entanglement entropy for the gapped valence bond solid ( vbs ) states as well as the kennedy triplet for the open chain@xcite.
csma / eca ( http://www.csma.org/csma/eca ) is a new protocol for the control of the mac queue in 802.11 networks.   it is based on the concept of an unsaturated state, where each network is about to enter in saturation, i.e. when all contenders in the contention are in the same range of packets in the queue at the end of each simulation. here   we present a look at some of the results of experiments that have been performed to test the performance of csma - eca and its competitor csma / ca.
neutrinos are the most elucidative indicators of new astrophysical phenomena. in this review,   some of the astrophysical implications of neutrino mass and mixings are discussed.   the status of the solar neutrini problem is briefly reviewed, and then some recent developments concerning physics input to solar models are discussed.understanding neutrine transport in inhomogeneous media is an essential part of understanding supernova dynamics. at some point during the collapse of a supernova, the inner core collapses subsonically, but the outer part of the core collapses supersonically. when the nuclear equation of state stiffens, tau neutrinos can escape from the core and travel to the outer edge of the supernova core via the interaction with the outer surface of the center of the collapsing supernova. as a result, the outer end of the collapsed core becomes more stable and the inner cores become more unstable.    neutrines can be detected in the outer core by observing the oscillations of flavor mixing angles between the two parts of the main core - collapse driven supernova ( i.e., the central and outer cores ). here  , i will focus on the
we investigate the effects of the symmetry term of the nuclear matter equation - of - state ( @xmath1 ) and the symmetry energy on the properties of fragments emitted in a reaction between proton - rich and neutron - rich systems at fermi energies.   we use the boltzmann - langevin ( bl ) approach, i.e. of transport equations including fluctuations, to study the collision dynamics of two - body collisions at 30 - 50 mev / a using the stochastic mean field ( smf ) method, where fluctuations are projected onto the ordinary space @xcite. for the low - density regime, that is the region of interest for our analysis, we adopt a soft eos, with compressibility modulus@xmath6 and for the density dependence of the symmetry energy, we consider two representative parameterizations, one showing a rapidly increasing behaviour with density, roughly proportional to @x Math9 ( asystiff ) and one with a kind of saturation above normal density ( asysoft, @x math10 ).    the results show that the asymmetry of the fragment isotopic content is stronger in the asysoft case, while the effect of the
intermolecular vibrational energy transfer occurs in a quite large number of chemical processes ranging from simple chemical reactions to very complicated molecular systems like molecular motors.   it has been the subject of numerous publications @xcite. among the large variety of experimental techniques used to investigate intramolecular or intermolescular energy transfer,   ultrafast two - dimensional infrared ( 2d - ir ) spectroscopy is one of the most promising methods to directly probe the intermolecules involved in this process. in this work  , we describe the appearance of the cross - peak observed experimentally and analyze in detail the influence of the dynamical constants on its magnitude. using an experimental setup based on three transform - limited ir femtosecond laser pulses and heterodyne detection to phase - resolve and to amplify the vibrational echo signal, we show that the intensity of the vibrations induced by the laser pulses depends on the interaction hamiltonian of the laser - system interaction with the molecular system under investigation. when the molecular vibrational states participating in the transfer of energy are dark states, most probably made of combination states of low frequency modes with very weak dipole moments or not at all optically active, co
optical lattices have been used to study the interaction between ultracold atoms and bose - einstein condensates in the optical periodic potentials created by intersecting laser beams.   the experimental results obtained by the pisa group on bloch oscillations, landau - zener tunneling and optical potential renormalization within optical lattice structures are reviewed. for the first time   we report on the effects of the temperature of the quantum degenerate gases on the atomic motion of atoms in optical latticing, as well as the interactions between the atoms and the optical potentials generated by the laser beams that intersect the lattice beams. from the experiments carried out since 1992,   it is clear that the most important aspects of the interaction among atoms within the optical lattixes are the long - range interactions that occur above and below the bose-einsteinian temperature. these interactions are more directly connected with the modulation of the spatial macroscopic wavefunction of the boscheidt - riemann condensate, which is a flexible source of atoms whose spatial dimensions and velocity spread can be controlled with large freedom, so that a condenate may be loaded with great accuracy into
giant planets in the outer solar system are believed to have formed beyond the water ice lines of their stars and migrated inward.   direct detection of these giant planets is limited to the most massive examples, and it is important to determine how many systems retain their giant planets on wide orbits. here   we review the recent work by @xcite and colleagues using the infrared spectrograph and multiband imaging photometer for the _ spitzer space telescope _ ( mips ) to investigate the structure of protoplanetary debris disks around stars of different stellar types that have been imaged by both the irs and mips. from the results of these studies, we propose that the size of the planetesimal belt and kuiper belt in the solar system may have influenced the location of the warm and cold debris disk components.
we study the thermodynamics of strange quark matter ( sqm ) in relativistic regime.   we use legendre s invariant metric to describe the geometry of gluons. by study singularities of scalar curvatures, we investigate the possibility of interaction in gluonic interactions. based on the riemannian geometrical methods which are used to construct general relativity, we can construct metric for thermodynamic of sqm and present a general formalism. by a careful analysis of singularities  , we find the critical points of these systems.
the rate of mass loss from unevolved late - type stars is notoriously difficult to constrain.   we examine the consequences for mass loss and energy loss of flare - dominated coronae based on extrapolation of the observed behavior of a large sample of coronal mass ejections ( cmes ) collected by the geostationary operational environmental satellite ( goes ) and the large angle and spectrometric coronagraph ( lasco ) on board the solar and heliospheric heliosphere mission, and compared with the predictions of a wind model based on the energy flux of magnetohydrodynamic turbulence from the subsurface convection zone developed by @xcite. using this model, we find that the mass loss rate of cmes in the x - ray luminosities of the most magnetically active solar - like stars can be as high as ~1000 times that of the sun, and that the energy loss from cmes can be several percent of the steady wind rate. at first sight   this suggests that cmes are going to be of little importance in the stellar context. however, on the sun cmes have been associated with flares, and magnetic activity is thought to be dominated by flares.
we study the force of the evanescent wave of a quasicircularly polarized guided light field of a nanofiber on a dielectric spherical particle.   we show that, for appropriate values of the size parameter, small spherical particles can be attracted to and transported along nanofibers by the beam of a guided light beam using a tractor light beam. in the case of a single - beam optical trap where the beam intensity is uniform along the propagation axis,   the gradient forces are strong enough to draw small particles along the beam axis. however, when the beams are directed in a direction other than the propagation direction, the gradients are weak and the particles are not attracted to the guided field.
the high frequency ( hf ) volatility of the eur / usd exchange rate volatility over successive 10 minutes intervals monotonically increases or decreases during specific time windows within the day.   the analysis of the ensemble of daily histories produced by such a process reveals a peculiar form of scaling obeyed by the probability density functions ( pdfs ) of the returns, once they are aggregated over intervals of variable span within a fixed intraday window. in this way, the pdf of the aggregate distributions of the individual returns is not only non - gaussian but also exhibits a scaling symmetry with the scaling function of the self - similar stochastic process, which is relevant for structural analysis of hf data, for financial forecasting, and, as we argue, for the identification of efficient trading rules.
time synchronization is an important problem in large distributed systems in that it allows the entire system to cooperate and function as a cohesive group.   recent advances in sensor networks show a clear trend towards the development of large scale networks with high node density, and these developments indicate that large scale, high density networks are on the horizon. time synchronization plays an important role in many applications, but the question of scalability is not yet fully understood. here   we present a new algorithm for the computation of time synchronization in large - scale networks based on the model of pulse - coupled oscillators, which is based on dynamical systems theory. using a set of state variables and a phase variable, we find that the rate of synchronization is proportional to the number of nodes in the network ; however, the rate at which each node synchronizes to the rest of the network is determined by the clock skew and the offset of the clock from the reference time source. when the clocks of all the nodes are synchronized to the reference Time source, the rates of synchronization across the network are significantly higher than those of the clocks at each element.. this finding is consistent with the results of previous work on the emergence of synchronization in complex networks of oscill
the highly nonlinear dynamics of fully developed turbulence generates high - amplitude fluctuations of the flow fields and their spatial derivatives.   these extreme events are solutions of the underlying dynamical equations which display a very rapid temporal variation with respect to a norm defined for the whole fluid volume. in this work, we demonstrate a direct dynamical link between a transition of the large - scale turbulent fields and the rare high - amplitudes events of the spatial derivatives which are sampled at the smallest scales of the turbulent flow far away from the boundary layers. in a three - dimensional turbulent rayleigh - bnard convection ( rbc ) flow in a closed cylindrical cell,   we show how the formation of a rare high-amplitude dissipation rate event in the bulk of the convection cell can be traced back to a plume emission from the bottom plate coinciding with a strong fluctuation of the big - scale circulation which exists in closed turbulent flows. in the latter case, a collision between a hot upwelling and cold downwelling plume is triggered which generates strong local gradients leading to a small - scale extreme dissipation ( i.e. velocity derivative ) event inside the container as well as at the edge
this paper presents a detailed analysis of the spiral structure of a sample of galaxies from the _ spitzer infrared nearby galaxies survey ( @xmath1 ).   the results show that the vast majority of the galaxy's spiral structure is grand design, and that the size of the arm - interarm regions is inversely correlated with the global star formation rate ( sfr ) measured from the near infrared ( nir ) imaging data. using a combination of observational and theoretical techniques,   we find that the sfr increases with the strength of the stellar spiral arms, and this increase is most pronounced in galaxies with large amplitude of spiral arms. by comparing the observed sfr with the predicted sfr from both qsss ( quasi - stationary spiral structure - lindblad 1964 ; lin & shu 1964, 1966 ) and sspsf ( stochastic self - propagating star formation - self - propagation model )  , we show that there is a strong inverse relationship between the magnitude of the shock and the number of stars in the galaxy, and suggest that the latter is due to the presence of an old disc component in the spiral arms.conclusionsthe results of this study provide a new dataset
the low - hard state ( lhs ) is the most common mode of accretion in black hole x - ray binaries.   the nature of the accretion flow in the lhs remains uncertain, and the fundamental assumption of a radially recessed accretion disc may find some support in the low disc reflection fractions which are sometimes measured in the hard state. here   we investigate this assumption using observations of swift j1753.5 - 0127, a black hole with a hard power - law spectrum at 1.4  1.7 kev and a hot optically thin plasma of soft seed photons arising from a thermal disc or magnetic structures. during its 2004 outburst at a luminosity of @xmath6 by both _ rxte _ & _ xmm _ @xcite, we found that a cool disc blackbody consistent with an optically thick geometrically thin accretion disk extending to the innermost stable circular orbit ( isco ) existed, in contrast to theoretical expectations. for the cool disc component,   a disc temperature of@xmath7 0.2 kev was required ; however, no significant disc reflection features were detected. on the other hand, while the hard power
the transverse momentum spectra of the produced hadrons in pp, pa and aa collisions at 2.76 tev have been obtained from the relativistic heavy ion collider ( rhic ) and large hadron collider.   the data are presented in terms of the tsallis distribution, which has been widely applied to describe the final particle production with great success by the theorists and experimentalists using the theoretical model @xcite. here  , we propose a new version of the Tsallis distributions for the charged particle spectra produced from high energy pb+pb collisions, which is based on the hydrodynamic term and two power - law terms, which are derived from the multisource thermal model @xmath21^{-\frac{1}{q-1 } }, \label{tsallis}\end{aligned}\ ] where @x Math22 is the entropic factor, which measures the nonadditivity of the entropy and @x math16 is the temperature.    the results show that the effective distribution @x maths24^q$2 = 0.037 + 0.0065 + 0,0,0.0004, where @
a stochastic series expansion ( sse ) algorithm for transverse ising models with long - range interactions is introduced in which the direct summation over the interacting spins is avoided.   the computation time scales with the system size n as @xmath2 times the spatial integral of the absolute value of the interaction . both local and cluster - type updates are developed for the model with arbitrary interactions. a cluster update is a generalization of the classical swendsen - wang cluster method from the quantum monte carlo method @xcite to the transversal ising model, and shares some features with a scheme previously used within the continuous - time world - line algorithm @xaite.. the integration of these features in the sse formalism should open new opportunities for detailed numerical studies of a wide range of important models.
the collective optical effects resulting from collective coupling of atoms to radiative environment have been known for nearly sixty years, and have been extensively investigated experimentally.   the experimental investigations of the collective effects were mostly restricted to the analysis of the superradiant states which appear spontaneously in the cascade emission and manifest themselves as a maximum in the intensity or photon emission rate. in this paper   we analyze the collective optical phenomena in ensembles of three and four quantum dots ( qds ). compared to double qds in which only one optically inactive state may be realized, @xcite ensembled of two and more two - level systems allow to realize many stable states which occur at different exciton occupations of the single emitters. by taking into account characteristic for those system properties which distinguish them from natural ones  , we include in our model the fundamental energy mismatches, different dipole energies, dipole dipole densities and dipole potentials of the quantum dots.the results show that the formation of the subradiance states is much more difficult in these systems because of their decoupling from the photon environment because of which they do not undergo radiative decoherence and thus may form deco
the abundance gradient of the interstellar gas in the galaxy is determined from the observed  line ratio ( t@xmath1 ), from the  line ratios ( t @xmath2 ), or from the balmer discontinuity ( t=xmath3 ).   the results have been used for different purposes including planetary nebulae ( pn ) classification and abundance gradient determination. in this paper  , we quantify the systematic error in the abundance gradient due to an overestimation of the gas temperature, using a monte carlo method. as proposed by peimbert ( 1978 ), the pn of the galactic disk can be classified in type i, ii and iii. however, our sample includes only type ii pn, which are probably more representative of the chemical evolution of the galaxy. since the oxygen lines are the main coolants, the gas temperatures of the pns must be lower closer to the galactic center. in addition, the forbidden line emissivities increase rapidly with the gastemperature reaching a plateau for t@Xmath5 5 x 10@x Math6k. therefore, a change in the gas heat from t@ Xmath1 to t@
we present a new catalog of isolated galaxies, 2mig, selected from the 2masx part of the @xmath3- band 2mass survey using a modified isolation criterion from the cig ( karachentseva 1973=cig ).   the galaxy with a standard angular diameter is classified as isolated if all its significant neighbours with their angular diameters locate on the projected distances not closer than@xmath8.  in addition, the galaxy without significant neighbours both in optical and ir bands entered in the " 2mass very isolated galaxy catalog " i.e. 2mvig. here  , we show the homogeneous dis distribution of the two catalogs with the slope of 0.6 @x Math10.
the cosmological principle was first adopted when observational cosmology was in its infancy.   it was then little more than a conjecture, embodyying occam s razor for the simplest possible model. if this assumption turned out to be invalid then the consequences to our understanding of cosmology would be dramatic, for example the conventional way of interpreting the age of the universe, its geometry and matter content would have to be revised. therefore it is important to revisit this underlying assumption in the light of new galaxy surveys and measurements of the background radiations. here   we examine the degree of smoothness with scale by considering redshift and peculiar velocities surveys, radio - sources, the x - ray background, the ly-@xmath0 forest, and the cosmic microwave background. using the friedmann - robertson - walker metric of space - time, we find that the universe is roughly homogeneous and isotropic on scales of local galaxy surveys ( @xmath2 mpc ) and the scales probed by cobe ( @Xmath3 mpc).we discuss some inhomogeneous models and show that a fractal model on large scales is highly improbable. assuming an friedmann riedman -
the idea behind the sp was put forward by efetov in 1979 in the context of layered superconductor with parallel magnetic field @xcite.   it was suggested that the field can suppress the inter - layer josephson coupling so that the low energy properties of this 3d system can be described as being essentially of 2d character. here   we present the results of the large scale monte carlo simulations of a simple classical xy system characterized by the gradient interactions and the josephalic coupling @xmath1, where the gradient terms are chosen in such a way that the sp is supposed to exist in some range where the renormalized value@xmath2 of @x Math1 scales to zero as layers size @x math3 grows. using the dual formulation of the model  in terms of the closed loops  our analysis is based on the rg logic and the main result is that no sp state exists in such an asymmetric xy layered model. instead, the value of @Xmath2 is always finite.    this behavior will be compared with the standard asymmetric yy layered models where no sp are expected to occur.. the numerical results have been
we show that in theories where the standard model ( sm ) neutrinos acquire majorana masses through the seesaw mechanism at the weak scale, the requirement that any pre - existing baryon asymmetry is not almost entirely washed out can be used to correlate the pattern of sm neutrino masses to the spectrum of new particles at theweak scale.   this is true for all three classes of seesaw models with a weak - scale @xmath0 gauge boson, except for the type iii seesaw model with a triplet vev and mass ( @x Math4,@xmath5 ) at the strong scale. if the baryons are generated at or below the weak level, or the pre -existing baryone asymmetry has been extremely large, this leads to definite predictions at the large hadron collider for each of the three types of sawaw models described above.
in the last few years, the universality of the stellar initial mass function ( imf ) has been questioned by the results of theoretical studies, which consistently predict that the first stars ( hereafter pop iii stars ) had characteristic masses of 100 - 600 @xmath3.   however, observations of present - day stellar populations show that stars form according to a salpeter imf with a characteristic mass of 1 @x math3, below which the imf flattens. in this study, we use a semi - analytic model of primordial star formation to investigate the relationship between the shape of the primordial imf and the probability that a pop iii star will end up as a massive black hole. using a pair - instability supernova model, we show that the number of pop iii+ stars with masses in the pair - stability supernova range is significantly higher than that of pop ii / i+ stars, and that the rate of metal ejection from the forming star is much smaller than that from the black hole during the formation of the first popii / i stars.. the observed rates of proton accretion are also significantly lower than those predicted by the current model, suggesting that the origin of the
the poincar - birkhoff theorem asserts that any area - preserving homeomorphism of the annulus isotopic to the identity has periodic orbits with rational rotation numbers in the rotation interval of the homeomorphic map.   the main goal of this paper is to describe an analogous theorem on general orientable surfaces with negative euler characteristic, where the rotation vector of a periodic point is associated with the rotation number of every point in the orbit of the periodic point and the rotation vectors of all the periodic points in the periodic orbit are also associated with their rotation numbers. by using the sharkovskii - type forcing result, we show that topologically monotone periodic orbits ( trivial braids ) are quite " rare " on surfaces with positive euler characteristics such that the existence of simple braids is not sufficient to prove the theorem.
the knowledge of neutrino interactions in the @xmath5  gev energy region is important because this energy domain is characteristic for majority of experiments performed during recent years and also those scheduled for the near future.   the most straightforward analysis of experimental data requires reconstruction of a neutrinos interaction cross - section, which is usually based on the observation of the leptonic and/or hadronic final states of the interacting neutrines. to estimate the value of @x Math10 the charged current quasielastic reaction ( ccqe )   must be considered as a parameter in the formula for free nucleon scattering. since the experimentally measured values of@xmath10 are not always the same, the aim of this paper is to discuss the issue of the accuracy of the calculated value of ~20% of the total cross - sections in the sub - gev region.
the theory of scalar field on de sitter metric has been intensively studied in the literature.   the solution of klein - gordon equation in this geometry was obtained and in addition the form of the feynman propagator was found. however, the interaction processes in scalar qed were less studied using perturbations and exact solution of field equations. in this paper   we show that the production of massive scalar particles in the presence of an external electric field in the early universe has a nonvanishing probability only in the large expansion of early universe when the mass of the particle is larger than the expansion factor. for this reason  , the momentum is not conserved in this process. to study the minkowski limit of our results we calculate the probability density of pair production and graphically represent it as a function of ratio mass / expantion factor.
dna - binding proteins are central to many essential biological processes.   most of these proteins have the ability to recognize and tightly bind cognate dna sequences ( sites ) bound by their cognate amino - acids, and the availability of crystal structures for many of them has made it possible to construct 3d models for a broad range of dna -binding proteins. here   we review recent work in the field of structure - based predictions of binding affinities for dna- and protein - dna interactions.
numerical relativity ( nr ) simulations of black holes ( bhs ) have been used in the construction of gravitational wave template banks for signal searches in gravitational wave detectors and in the context of gravitational - wave data analysis.   the purpose of this article is to provide an overview of the most recent developments in these areas which, for reasons of clarity, we divide into three categories : ( i ) numerical studies of fundamental properties of bh spacetimes, ( ii ) applications to the modeling of trans - planckian scattering and ( iii ) the gauge gravity duality. as complementary reading to this article,   we note review articles including nr applications in high - energy physics involving bhs in higher dimensions.
we study the effects of custodial @xmath3 breaking counterterms in the next - to - leading order effective lagrangian.   we focus on a special operator, that apart from breaking the custodial symmetry, violates parity and charge conjugation while conserving cp. for the first time  , we show that this operator is unique, and that violating parity can in principle produce signatures that will set it apart from the other next-to - leading terms in the effective Lagrangian with respect to the strength of the electroweak corrections.
the analysis of low - temperature properties of systems with electron - phonon interaction is challenging as strong repulsive interaction among electrons confined to molecular orbitals leads to surprising results such as the interplay of the kondo physics and molecular vibrations, which are intractable to conventional perturbational approaches. here   we consider a molecule undergoing a linear transport measurement where the vibrational mode that modulates the tunneling amplitude is coupled to the electron density at the molecule ; ( ii ) the molecule possesses in addition to the cm mode a breathing mode which modifies the energy level of the molecular orbital.   experimentally, the cm modes are discerned in nonlinear transport measurements as side - bands in conductance which correspond to frequencies which do not match any of the eigenmodes of a given molecule. for the case of a molecule without the cm oscillations described by the anderson - holstein hamiltonian,   the dominant effect of the coupling to the breathing mode is the reduction of the repulsive interactions among electron pairs occupying the molecular Orbital space. when the reduced repulsion is positive, a gate - voltage sweep reveals the area ( of width of order @xmath0 ) of enhanced linear conductance
we solve the eliashberg equations for d - wave superconductivity in the heavy - fermion compounds cecu@xmath6si@x Math6 @xcite and ceirin@x math7 @xaite using a phenomenological afm spectral function with which the experimental data are in good accord.   we find that the ratio of the transition temperature @xmath0 to the typical electronic kinetic energy parameters @xMath3 is more than @x maths4, whereas the correlation length of the antiferromagnetic fluctuations at the fermi - surface is much smaller than those at the interface between the two phases. by comparing the calculated values of the measured transition temperature with the calculated ones, we conclude that the influence of inelastic neutron scattering on the superconducting transition temperature can be explained by the contribution of the afm fluctuations to the anomalous resistivity in these compounds.
the yields of oxygen and magnesium from type - ii supernovae ( snii ) of the most massive stars in clusters depend upon the mass of the progenitor.   we show that the cluster mass function ( cmf ) is a power - law with a slope between lower and upper mass limits @xmath12 and@xmath13, and that the number of stars in each cluster can be increased by changing the cmf. using a monte carlo sampling method  , we find that the effective upper mass function of the galaxy is reduced by about 2% in the galactic bulge and by about 1% in central regions of large elliptical galaxies compared to the solar neighbourhood. for oxygen,   the effect of this change is more pronounced in the northern region of the Milky Way than in the southern region. for magnesium, the effect is more prominent in the centre of the galactic halo and the thick disk, but the effect on oxygen is also apparent in the early stages of star formation in the bulge as well as in the central parts of the globular nucleus. these results are discussed in terms of their implications for the yields of heavy elements in galaxies of different types and masses.
anderson localization of electronic states in a disordered system is a path breaking observation that has extended its realm well beyond the electronic properties of disordered solid materials, and has been found out to be ubiquitous in a wide variety of systems such as the photonic, phononic, polaronic, or plasmonic lattices.   the existence of real continuous bands are reported recently in quasi one dimensional or two dimensional systems only with diagonal disorder, and it remains to be seen whether such bands of extended eigenfunctions can be generated and controlled with off - diagonal disorder are well. in this communication   we show that, in quasi - one dimensional ladder networks withoff - diagonal quasi - periodic order it is possible to engineer absolutely continuous bands of energy eigenvalues. by attaching a single quantum dot ( qd ) from one side to a selected set of lattice points in every strand of the ladder,   one can create _ absolutely continuous subbands in the electronic spectrum of such quasi 1-d systems.the results are discussed using a tight binding hamiltonian and a real space renormalization group ( rsrg ) method.
the speedup in the path integral algorithm is a direct consequence of new analytical input that has come from the study of the relation between discretizations of differing coarseness of the same theory.   the aim of this paper is to give a detailed exposition of a systematic analysis that leads to the best solution in the class of all equivalent effective actions that lead to the fastest convergence of the associated discrete amplitude @xmath31 to the continuum expression, i.e. the effective action that results in the largest convergence to the limit of the continuum amplitude. for theories with action of the form@xmath14 we will look at theories with both discrete and discrete amplitudes ( e.g. quantum mechanical and non - quantum mechanical ) of the general quantum mechanical amplitude given in terms of a path integral which is simply the range of the euclidean time steps of the expression @x Math7$]/xmath8. using the method presented in a recent paper by barker and henderson, we have found that the optimal choice of discretization procedure for the naively discretized action of each theory is determined by the number of terms that explicitly vanish in the continuum limit. when these terms are
the electron transport of electrons through a quantum dot ( qd ) coupled with three metal leads is studied in the context of a nonresonant coupling between leads driven out of equilibrium by means of a dc voltage bias and time - dependent external fields.   the transmission coefficient of the electron transport through a qd connected with three leads described by the infinite - u anderson hamiltonian is found to be in the range of 0.5 to 1.0  ev. under the influence of an ac external field the current flowing through the qd under periodic modulation of the quantum dot electronic structure and the tunnelling barriers is reduced by a factor of 2.1, while the charge carries through the tunneling channel are not affected by the external field. for the system with two leads each coupled with one of the other two leads, the effect of the dc voltammetry bias on the conductance curves is explained by the interference of the energy levels of the left and right leads.
kempe s universality theorem @xcite is one of the great theorems of theoretical mechanism science.   it states that any bounded portion of a planar algebraic curve can be traced out by one joint of a linkar linkage with revolute joints. in this article  , we extend the ideas of@xcite to rational space curves and provide a construction that works for all rational spaces curves and, at the same time, reduces the number of links and joints needed to draw an arbitrary rational space curve.we use rational motions of minimal degree in the dual quaternion model of rigid body displacements for the link that draws the given space curve. if the curve is entirely circular, the motion degree is particularly low and factorization of the motion polynomial is straightforward, without the need for prior degree elevation. in the case of non - circular curves,   we only preserve one relevant trajectory, not the complete rational motion.we also introduce several new ideas that also improve the planar case. among them   are the use of bennett linkages whose configuration curves have only one irreducible component and the fact that the configuration curve is free of spurious components.
we study the convergence of finite elements on evolving surfaces with prescribed motion using the evolving surface finite element method ( esfem ) for mean curvature flow of closed surfaces.   we consider different velocity laws for coupling the surface motion with the diffusion on the surface, and study the stability and convergence properties of the semidiscretization of the esfems for finite elements of polynomial degree at least two for a series of linear finite elements. in particular, we study the effects of the regularized velocity law based on the density and mass balance of the surface coupled to diffusion on it, which are determined together with the solution value and tangential gradient of the parabolic equation. by combining the constant - time evolution of the discrete velocity of the evolving plane with the regularization parameters of the semi- and full discretizations, we obtain a complete stability analysis of the euler  lagrangian variant of the siemann   dziuk   elliott method for the standard model problem of evolving a linear parabolic equations on a moving closed surface where the direction of motion is prescribed as a function of the solution values of the partial differential equation and the tangential divergence of the given velocity.
the properties of the circumstellar ( cs ) dust grains are linked to the effective extinction laws caused by interstellar ( is ) dust.   it has been shown that the extinction laws for type ia supernovae ( sne ia ) have a non - standard nature, and that they deviate from the standard extinction laws derived for milky way, large magellanic cloud ( lmc ) or small magellanic cloud ( smc ) environments. in this paper, we investigate what is the main factor that determines the characteristic properties of an effective extinction law toward a steady - emission light source through a plane - parallel dusty cloud. in doing so, we adopt various dust models and systematically compute resulting effective extinction Laws, by performing monte carlo radiation transfer simulations.. we especially focus on the total - to - selective extinction ratio, @xmath0, which represents a slope of the extinction curve in the optical regime. using these simulations,   we first analytically derive expected relations between an effective survival law and properties of cs dust grains under the plane -allel approximation for the distribution of dust grains, and show that the results are in good agreement with the observed values of @x math0
the number of alternating sign matrices ( asms ) for a finite square grid is determined by the orientation of the boundary edges, which alternate in color depending on the color of the initial vertices.   we show that there are as many asms with the new pairing as with the old one, as conjectured by carl bosley and lukasz fidkowski@xcite, and that the new one is an explicit bijection.
surnames and languages are cultural traits whose transmission bears strong similarity with that of some biological features.   they are transmitted from ancestors to their descendence, in a process analogous to inheritance, and are subject to changes, similar to mutations, by interaction between individuals such as teaching and imitation. among them   we find languages and surnames. for languages and species,   the distribution of the number of subtaxa within a taxa displays scaling properties, quantitatively similar to those disclosed in biological taxonomy. for surnames, the fraction @xmath1 of individuals bearing a given surname decreases with increasing number of individuals, and the proportion of individuals carrying the same surname increases with increase in number of people. this relationship is consistent with the observation that the extinction of a surname and the persistence of a non - recombining neutral allele are equivalent problems.
quantum coherence ( qch ) plays an important role in today s physics, more specifically in physics of low temperature starting from the laws of thermodynamics and most recently in the emerging area of quantum information theory.   it has been useful in understanding the underlying process of efficient energy transfer in complex biological systems. in the recent past   researchers have attempted to devolop a framework to formalize the theory of qch within the realms of quantum resource theories. in this context   qch is quantified in terms of the functions of coherence monotones. here   we present a new framework for measuring qch in finite dimensional systems and a theoretical measure satisfying the reliability criteria was established in the context of quantum resources theories.
spatial sparsity is a property of convolutional neural networks ( cnns ) that allows them to process sparse images more efficiently.   it is particularly important for image recognition and character recognition, as these are two of the most challenging problems in computer vision. here   we describe how sparsity can be used to combine the best features of both types of applications. using a family of deepcnet networks with many layers of max - pooling, we show that sparsity improves the speed of the computation of sparse data by increasing the spatial information retained in the input data. when the input image is spatially sparse, it is possible to apply the network to a number of overlapping subsets of the image at no extra cost. this means that the whole object can be evaluated in one go, with a substantial amount of padding added at no additional cost.
we study the relation between phase lapses and population inversions of the effective hamiltonian levels of a single - level quantum dot and spin - polarized electrons using a renormalization group and bethe ansatz analysis of the effect of the coulomb interaction and coupling to the leads.   we show that the phase lapse and transmission zero behavior appearing at small levels can be understood as resulting from a fano - type interference effect involving transport through two or more effective dot levels, whose position and width have been renormalized by the kondo effect. for a single wide and several narrow level with strong interaction,   the effects of phase lapsing and zeros of the transmission phase are well - separated, whereas for a few- and many - electron dot, they are mesoscopic.
a practical single photon source should meet the demands of high fidelity, brightness and efficiency.   parametric down - conversion ( pdc ) enables conditional state preparation  heralding on one of the twin photons ( idler ) gives exact timing information about the other ( signal ). in this paper   we show how to optimally adapt the bandwidth of the filter such that the trade - off between the fidelity and brightness of the source is balanced. using hong - ou - mandel type interference, we study the statistics of the heralded state and finally determine the spectral overlap between signal and reference by directly extracting the overall fidelity of a heralded single photon by utilizing the hom interference.
the cdex-1 ( china dark matter experiment ) is a new experiment at the china jinping underground laboratory ( cjpl ) with a ton - scale point - contact germanium detector array for low - mass wimp searches in @xcite and studies of double - beta decay in @xmath2ge.   the first results with 53.9 kg - days of data taken from august to september, 2012 and a threshold of 400 electron equivalent energy ( evee ) were reported @xcite, providing an order of magnitude improvement on the spin - independent @x maths4-n coupling ( wimps denoted by @x Math4 ).    the second phase of the experiment has been conducted since november 2013, with an active nai(tl ) anti - compton ( nai - ac ) detector installed at the same site, and the results with 335.6 kg -days of data taking have been reported   @xfite. here   we describe the details of the cdEx-1 experiment and report the results based on the design of the first phase.
polyelectrolytes in salt solutions exhibit striking phenomena while multivalent salts or charged molecules are added into the solutions.   these phenomena are called " reentrant condensation " or commonly referred to as " dna condensation" in the fields of biology and medicine. despite decades of effort,   our understanding on polyelectrolyses is still limited and many issues, including the reentrants condensation, are far from being resolved. in this paper, we investigate the properties of polyelectromolecules in salt - free solutions by means of computer simulations. using a single - chain model, we find that the phase boundary of the window of concentration of the added salt depends linearly on the concentration of polyElectrolyte but the upper one of the windows is insensitive to it and roughly a constant. moreover, by varying the ion size, we have shown that the excluded volume of ions plays a decisive role on the redissolution of poly electrolytic chains.
the iron line profile in the seyfert 1 mcg-6 - 30 - 15 supermassive black hole ( agn ) is broad with a velocity width of @xmath4 cm sec@xmath5.   the most straight forward interpretation of this feature is the disk line model where the line is broadened due to the combined effects of doppler and gravitational red - shift in the vicinity of a black hole. here   we examine models for the broad iron line that do not require strong gravity such as the comptonization model, which predicts a narrow iron line with an extended red wing. by fitting the data to these models, we show that the peak centroid of the line can be fitted close to @x math9 kev.    this would imply that the black hole is spinning close to its maximal value and that the iron line emission arises from the region inside the last stable orbit.
i first met bill in 1972 when i was a student at the lawrence livermore national laboratory.   sixteen years later I was a group leader for the national magnetic fusion energy computer center ( nmfecc ) where innovations in computer hardware and software led to the first interactive operating system, the first unclassified national network, and the era of the cray supercomputers. during his third sabbatical leave from das in 1989   we traveled to japan to visit shuichi nos at keio university in yokahama and spent the academic year 1989 - 1990 working together with professor kawai, who had an interest in statistical mechanics, while bill was working with professor taisuke boku, a parallel - computing specialist, and a physicist sigeo ihara at hitachi s kokubunji laboratory.our biggest project in japan involved a baker s dozen of physicists, engineers, and computer scientists working on a two - dimensional model of million - atom two- and three - dimensional " plastic flows ", flows of solids in response to shear stress. this work allowed us to study the kinetics of grain formation during annealing. over the next few
inflation is the leading paradigm for the very early universe cosmology.   the recent bicep2 experiment reports an over @xmath6 detection of gravitational waves, with tensor to scalar ratio@xmath7 this corresponds to a gravitational wave fluctuation amplitude @x Math13.  in this paper, we explore the possibility of blue @x maths13. in section   , the bound on @x math13 is derived from the bice p2 and polarbear @xcite data. in sections , a few other possibilities are discussed, including external sources for tensor modes, modified gravity and matter bounce. in part   i, we show the constraints on @Xmath14 and @xMath13 from biceP2, _ planck _ and polar bear data.. in part ii, we discuss the theoretical implications of the results.
the relativistic character of the charge carriers in graphene has attracted a lot of interest.   the unconventional quantum hall effect, klein tunnelling and the landau level spectrum@xcite have shown that electrons in a layer of an hexagonal lattice of carbon atoms behave as two dimensional massless dirac particles with a velocity 300 times smaller than the speed of light. here   we investigate rhombohedrally stacked multilayered systems using the two band approximation @xcite and present analytical formulae for different thermodynamic quantities as a function of the number of layers for zero and non zero temperature.we find that our results are fundamentally different from those of a conventional two dimensional electron gas ( 2deg ) due to the different landau levels spectrum and in particular because of the presence of a highly degenerate zero energy Landau level.    the results however still show the vanishing magnetization at zero magnetic field, which is a signature of the two dimensionality of the system.
estrogens are essential endogenous hormones that modulate the development and homeostasis of a wide range of target tissues, such as the reproductive tracts, breast and skeletal system. for estrogens such as 17@xmath0-estradiol ( e2 ) to exert their biological effects, they must interact with cellular estrogen receptors ( ers ).   these ers are members of the nuclear receptor superfamily of ligand - modulated transcription factors, and are encoded by two different subtypes, referred to as @xmath3 and @x math0, each encoded by a separate gene. recently, nagler et al reported the novel er@x Math5 and both er@Xmath0 isoforms in the rainbow trout, _ oncorhynchus mykiss_, and performed a comprehensive phylogenetic analysis with all other known fish er gene sequences.. the purpose of the study is to employ molecular dynamics simulations to determine the binding affinities between e2 and ers of the different isoform in the Rainbow trout and to use the results to provide insight into the underlying evolutionary selection pressure on the ers. using the lamarckian genetic algorithm, we show that e2 binds pref
the main idea of this paper is that proving homological mirror symmetry ( hms ) is like studying birational transformations ( noncommutative included ) on a and b sides of hms.   we introduce an analogue of the canonical divisor measure for minimal model, which is the local geometry of the singularities and a fiber at infinity of the landau  ginzburg ( lg ) model. in the case of fanos we show that all fano varieties via their degenerations are connected by simple basic links  projections of a special kind. with this observation   the correspondence between usual and categorical approach to birational geometry looks as in table   =  +.extended kawamata program.     0.1 - 1.2" ].
diluted magnetic semiconductors ( dms ) with transition temperatures as high as 150k or even above room temperature are attracting much attention lately in part because of possible ` spintronic'applications.   the experimentally measured dc - resistivity in dms materials @xcite shows interesting behavior strongly depending on the concentration of the magnetic impurity and temperature. in this paper   we present theoretical calculations for dms transport properties and study the role of the carrier - spin coupling which are crucial for ferromagnetic properties. using a recently developed non - perturbative method, the " dynamical mean - field theory " ( dmft,@xcite )  , we show that the dms dc - Resistivity is strongly dependent on the carrier density, doping of the material, and temperature revealing key features of the underlying physics. our results show many similarities to colossal magnetoresistance ( cmr ) manganites where the transport properties are influenced by the exchange interaction between the carriers and the localized moments as spin fluctuation scattering contributes to the resistivity.
the helix ( ngc  7293, pk  3657.1 ) is the nearest planetary nebula with a massive molecular envelope.   it is exposed to strong uv radiation from the central star which is expected to establish photodissociation regions with an important component of atomic gas at the interface with the ionized gas. in this letter   we report the detection of the 609  @xmath0 neutral atomic carbon ( ci ) line in the helix by using the 10.4  m telescope of the caltech submillimeter observatory and the spectroscopic mapping of the components in co. the observations show that ci is a major constituent of the neutral gas in the globules.
a new, random - access and rewritable dna - based storage architecture based on dna sequences endowed with specialized address strings that may be used for selective information access and encoding with inherent error - correction capabilities is presented.   the addresses are designed to be _ mutually uncorrelated _ and to satisfy the _ error - control running digital sum constraint _. given the address sequences, encoding is performed by stringing together properly terminated prefixes of the addresses as dictated by the information sequence. in this encoding method,   each address is chosen to be at large hamming distance from each other, so that it is highly unlikely for one address to be confused with another address or with another section of the encoded blocks. furthermore, selection of the blocks to be rewritten is made possible by the use of a special form of prefix - synchronized coding, which allows for selective access to the reads of interest, and can be controlled by the presence of read - only storage.
the prediction of crystal structures from first principles has long been recognized as one of the outstanding challenges in solid state physics.   the most recent methods of cluster expansion assume the lattice structure of the crystal @xcite, but this is not always the case. in this communication   we demonstrate a new method for unbiased _ ab initio _ crystal structure determination using a novel genetic algorithm which makes no assumptions of atom number, unit cell or lattice structural features and uses a periodic cut in the crossover operation to generate population members instead of a planar one. by taking the periodic cut through the center of each population member, we can reduce the number of discontinuities in the offspring operation and improve the convergence of the results compared to the conventional planar approach.
abstractthe mass loss rate and kinetic power of broad absorption lines ( bals ) from quasars are poorly constrained by the global covering factor, column density and the gas density or distance.   we show that these parameters can be estimated from the absorption lines of a subset of bal qsos, mostly felobals, with measured absorption lines from low - lying excitation levels of heavy elements. in this study, we use a combination of quantum chemical calculations and x - ray photoionization modeling to estimate the mass outflow rate, kinetic power and mass loss rates of the two types of bals from a large sample of bal region ( balr ) quasarities. for the first time, we find that the global cover factor and column density of the qsar have been determined from the emission lines of both the intrinsic broad and narrow absorption lines at the same wavelength using a range of analytical techniques. as a result, the massoutflow rate is very large for the majority of bal rqs ( @xmath2 m@xmath3  yr@x math0  ), while the kinetic power is small for the vast majority of qsrs ( ~10% of the
in general relativity, the orbits of test particles around a spinning black hole are characterized by three characteristic frequencies : the azimuthal ( keplerian ) frequency, the ( radial ) epicyclic frequency, and the ( vertical ) epika - cyclic frequency.   all three frequencies depend on the mass and spin of the black hole, as well as on the radius of the orbit. in this review,   i discuss the potential of measuring black - hole spins and confirming the predictions of general relativity using the rapid - variability properties of the observed frequencies of quasi - periodic oscillations from galactic black -hole binaries. for each orbital radius around a black hole with a spin parameter @xmath3, the highest frequency of the three frequencies decreases monotonically with radius and the maximum frequency of any _ lowest - order, linear _ quasiexperimental model of relativistic accretion flows is expected to be the highest among the three. however, the imprint of the spins of black holes on their spacetimes is very weak at the large distances from the horizons, i.e., the dragging of inertial frames, where the observed orbits reside. therefore, it is expected that
short - hard gamma - ray bursts ( shbs ) are a new sub - class of short - duration gamma -ray bursts ( grbs ) that were first detected by the _ vela  satellites @xcite in 1993.   they are thought to result from the death of massive stars, but their origin is not well understood. here   i provide a short account of the discovery of the first afterglows of shbs starting in may 2005, and discuss the growing understanding achieved with each burst.
we present preliminary results from a fabry - perot study of ngc 5457 ( m101 ).   the observations were carried out during the night of july 23 - 24, 2001, with the unam scanning fabry-perot interferometer ( sfpi ) puma attached to the f/7.9 ritchey - chretien focus of the 2.1 m telescope at the observatorio astronmico nacional at san pedro márder, b.c. for this galaxy, we have obtained the radial velocity field of the hii region population and the rotation curve of the galaxy.
in this paper we discuss the potentials and electric fields of uniformly charged line segments in two and three spatial dimensions, and we compare and contrast them with those of ellipsoidal equipotentials for any number of spatial dimensions.   we find that the linear charge distributions that give rise to ellipse - like equipotential configurations in @xmath2 dimensions are counter - intuitive in the sense that the charge distribution needed to produce ellipoides is counter -intuitive in higher dimensions. by interpolating continuously between intuitive and counter - intuitionistic charge distributions for segments with ellip soidal Equipotentials, we show how the various line segment results also give solutions to a class of electrostatic boundary value problems where the charge is moved outward and distributed on one of the equipotentially adjacent segments.
experiments to measure the flux of uhecrs have detected a number of events with energies @xmath1.   these observations present something of a puzzle, since there are no obvious mechanisms within our galaxy that could accelerate u hecrs to these energies. in this article  , we propose an alternative solution to the gzk cutoff problem, based on a significantly lower cmb photon number density that arises naturally from an alternative cosmological model @xcite. using the quasi - static universe ( qsu ) model, we show that the relationship between the planck scale and the quantum gravity of the universe no longer holds true for photons emitted at times@xmath10, where the present state of the cosmos is assumed to be very hot. as a result,   the observed uhecr spectrum is much more consistent with the qsu model than with the conventional formalism.
it has been claimed that radiative corrections to the majoron coupling in the see - saw model @xcite would induce non - diagonal components to the neutrino - majoron couplings.   it is shown that this is not the case. at one loop level   the main component of the majoronic version of the zee model  is diagonalised into the mass eigenbasis in the same way as the standard model higgs coupling, so that the neutron decay is described sufficiently well by the tree level result. for the secondary components of the mass matrix,   these are diagonalised back to the original diagonal form.
radio observations of ultracool dwarfs ( ucds ; @xcite ) are important for the study of the magnetic properties of low - mass stars, brown dwarfs, and planets.   we report the arecibo detection of a new radio - emitting t - dwarf, wisepc j112254.73 + 255021.5 ( j1122 + 25 ), in the course of the second part of our unbiased survey of late l and t - type Ucds at 5 ghz using the electron cyclotron maser ( ecm ) radio telescope. to our knowledge, this is the first detection of an ultra - fast rotation period from a radio - emitted ucd by the ecm. if confirmed, it will become by far the shortest one measured for any ucd.
the atacama cosmology telescope ( act ) @xcite is a six - meter diameter telescope located at an elevation of 5,190 meters on cerro toco in the andes mountains of northern chile.   the advact instrument will consist of four multichroic, polarization - sensitive tes bolometer detector arrays that will be sensitive to two frequency bands : 150 and 230 ghz in a high frequency ( hf ) array, 90 and 150 ghz for two middle frequency ( mf ) arrays, and 28 and 41 ghz with a low frequency ( lf )array. each array will be cryogenically cooled to 100  mk using a dilution refrigerator ( dr ), which allows for continuous cooling, increases detector sensitivity, and is also required for many of the superconducting components of the detectors and readout to operate. here  , we present the design, fabrication and assembly of the advactsensor and feedhorn wafers as well as the mechanical array structure used to house all of the 100 mk electronic components.    we also describe new structural components that have been built to allow advact array packages to integrate with the existing actpol receiver.
radio observations of merlin early - type ( s0a ) seyfert 1.5 galaxy mrk  6 have shown that the source has radio emission on both small and large scales.   however, due to the relatively poor resolution of the westerbork synthesis radio telescope ( wsrt ) and the limited @xmath5@xmath6 coverage ofMerlin, few conclusions could be made on the relation between the three scales of radio emission in this source. using the very large array ( vla ) with the redshift of @x Math10=0.01881 ( recession velocity @x math05640  km  sec@xMath2 ), we undertook a comprehensive radio study of mrK  6 with the vla at @x maths11  6  cm ( 4860 mhz ) and @x mathematics11  20  cm/1430 mhz during 19951996. for the first time, we show that the radio structure observed by @xcite is not aligned with the ionization cone or the optical polarization position angle ( p.a. ) derived through spectropolarimetric observations ; however, there is evidence of a pair of
the light - cone sum rules ( lcsrs ) for the hadron form factors at large momentum transfer @xmath4 give access to the light - front wave functions at small transverse separations between the constituents, called hadron distribution amplitudes ( das ), although perturbative qcd factorization @xcite does not seem to be applicable for realistic @x math4 accessible in current or planned experiments.   the problem is that the leading contribution involves two hard gluon exchanges and is suppressed by the small factor@xmath5 compared to the " soft " ( end - point ) contributions which are subleading in the power counting in @x Math6 but do not involve small coefficients.. we propose a new approach to calculate the soft contributions to the form factors as an expansion in terms of nucleon das of increasing twist using dispersion relations and duality.    this method is known as light - cones sum rules  and provides one with the most direct relation of the hadrons form factors and das that is available at present, with no other nonperturbative parameters. 	 the results suggest that the momentum fraction distribution of the valence quarks
the importance of nodes is a foundational problem in the field of data analysis of complex networks.   researchers have reached little consensus on this concept, but fortunately most concede that it can indeed be described by some rules or the intuitive ideas. based on the investigations on these definitions, we suggest that a set of four rules can be used to characterize the node importance in common circumstances. however, these rules often conflict to the others. here  , we propose a solution to resolve the conflicts using the equivalence classes.
the absolute abundances of @xmath8he, @x Math9d, and @x math0li synthesized in the first three minutes following the hot big bang ( bbn ) provide the key to a determination of the universal baryon density via its relationship to the @x maths3 parameter.   previous attempts to measure the primordial levels of these light elements in extragalactic sites have been hampered by the detection of two different values for each of their abundances, which is opposite to the expectation, based on one - zone models of chemical evolution, that the amount of@xmath9d is should decrease following bbn as the result of various destruction processes. in this paper   we employ the sn - induced chemical evolution model presented by ryan, norris, & beers ( 1999, hereafter rnb ) to derive a new value for the total expected contribution from galactic cosmic rays ( gc ) and supernovae ( sne ) during the first 10@x mathematics0 to 10 years of early star formation in the early galaxy using data from the so - called spite plateau at low metallicity where the observed slope in the spite plateau is incredibly thin, with an intrinsic star
in this paper we interpret a magnetic flow as a geodesic flow of a finsler metric in the plane whose geodesics are circles of a fixed radius.   we also describe the magnetic version of the string construction that recovers a billiard table by a caustic of the billiard map, and characterize the metrics for which the finsler billiard enjoys the familiar law  angle of incidence equals angle of reflection " ( theorem  and corollary  ). in particular, we focus on the case of a charged particle confined to a domain with ideally reflecting boundary, where the particle moves inside according to equation (  ) and undergoes elastic reflections off the boundary : the tangential component of the velocity remains the same and the normal one changes sign.
a gem - based time projection chamber ( tpc ) is one of the two options for the central tracker of the panda @xcite experiment at the new facility for antiproton and ion research ( fair ) at darmstadt, germany.   the gem - tpc tracker should provide a spatial resolution of @xmath4 150@xmath5 m, @x Math6 1 mm, a momentum resolution of about 1% and at the same time minimize the amount of material in front of the electromagnetic calorimeter. in this work   we describe the prototype tpc prototype. as a first step  , a small test chamber was built and characterized with cosmic mouns @xaite. erythroid pads were used to measure the signal quality of the read - out electronics. in order to characterize the test chamber with an external track definition in a particle beam, a new multi - purpose tracking system has been set up at the electron stretcher and accelerator elsa, bonn. four gem planes and four silicon detectors have been installed on a mobile test bench bench bench to be used as a reference for tracking. during the first tests with ~500 mev the electron beam available at
the inner structure of dark matter haloes has been the topic of some discussion in recent years.   observations suggest that the dark matter distribution in disk galaxies has a roughly constant density core, with a typical size of order a few kpc. on the other hand,   numerical simulations based on the ( @xmath0)cold dark matter ( cdm ) paradigm suggest a very steep inner mass density distribution, a so - called " cusp " @xcite . here   h04 present a novel method to fit rotation curves derived from their simulations as well as low surface brightness ( lsb ) galaxy rotation curves from the literature. using this method and the distributions of respective fitting parameters h04 conclude that the observed curves are consistent with the cdm paradigm ; a conclusion that contradicts a large body of observational work.
celeste was a cherenkov experiment using 53 heliostats of the former lectricit de france solar plant in the french pyrenees at the thmis site.   it detected cherenovkov light from electromagnetic showers produced in the atmosphere by the @xmath0-rays coming from high energy astrophysical sources. to constrain the energy scale of the experiment we improved the optics simulation, now in good agreement with the data and the data analysis has also been improved so that we have better background rejection. for the star 51  uma ( m@xmath1 ) which is in the field of view ( fov ) of mrk  421, the new simulation with our corrections ( red stars ) fits the data well whereas the old simulation was 50  % too high. this study helped us to perform our selection criteria for the data : all data that are too low in currents on the star have also low trigger rates.
the orientational phase transitions in the hexagonal phase of a diblock copolymer melt subjected to steady simple shear flow are studied theoretically.   the symmetry pattern of this phase consists of hexagonally packed cylinders made up of blocks of one type immersed in the surroundings of the other blocks. at low shear frequencies the lamellae have their normal parallel to the velocity gradient ( the parallel orientation ), while at high shear frequency the lamework is perpendicular to the vorticity direction of theShear flow ( the perpendicular orientation ). at lower temperatures   both orientations are more stable than at higher frequencies.
the extended nambu - jona - lasinio ( enjl ) model is a typical example of a class of low energy hadronic models with quarks that incorporates chiral symmetry correctly.   the aim of this investigation was twofold : + * 1 * to understand the relation between chiral symmetry and the concept of constituent quarks and + * 2*) to understand why this class of models works so well phenomenologically.we show here the results for the low - energy parameters of chiral perturbation theory. fitted are the @xmath18 parameters that are the free parameters at next - to - leading order. in the chiral limit,   these parameters are set by the only dimensionful parameter we fit here, the pion decay constant in the bimolecular limit,@xmath20  mev.    the main conclusions are : +*1 * ) in a sense the constituent quark mass is the same as the quark - anti - quark vacuum expectation value ; +*2 * ) the phenomenological success of the model rests on 3 bases : ( 1 ) the short - distance behaviour of these models has a lot in common with qcd ; (
we study the influence of radial and vertical mixing on the chemical evolution of a 2d non - static ( dynamical ) chemical disk model of the dm  tau outer disk.   the model is based on a steady - state irradiated disk model developed by @xcite, which assumes that the gas - phase co is enhanced in the outer part of the protoplanetary disk due to radial advection from the central star. we show that the solution to the enhanced gas -phase co can be found within the framework of a two - dimensional ( 2d ) non -static ) chemical model, even though the abundance predicted in the current study is still lower than observed.. the effect of radial mixing is explained by the fact that the diffusive turbulent transport processes are not independent of the time - dependent chemistry but are rather related to the angular momentum redistribution and associated global mass transport phenomena.
we present the first results of an analysis of the publicly available macho light curves.   we have analysed macho lights curves for 6833 stars that were originally classified as eclipsing binaries. after re - determining the period and classifying the stars based on their light curve shapes, only 3031 stars remained as genuine eclipsing or ellipsoidal variables ( the rest being cepheids, rr lyraes and other non - eclipsing variable stars ). in about 40 eccentric binaries we measured different o  c variations for the primary and the secondary minima, which indicates apsidal motion. from the 8 years of macho observations we measured about 80 parabolic and 45 cyclic period changes, the rest showing linear o   c diagrams. with this we double the number of known binaries with aps tidal motion in the lmc.
the large binocular telescope interferometer ( lbti ) is a mid - infrared instrument designed to characterise dust populations in the " habitable zone " ( hz ) of nearby stars at levels just a few times greater than the solar system s zodiacal cloud.   the aim of this paper is to outline a model for interpreting observations from the Lbti, and to show how this model can be used to derive the distribution of dust levels given an observation of thermal dust emission. using the model  , we show that the expected levels of dust that could be detected by the lbta are 1.5 - 2.5 orders of magnitude higher than the sun, and that these levels are suitable for earth - like planets in the habitable zone where earth - imaging will be attempted in the future.
we investigate the green - schwarz ( gs ) cancellation conditions of anomalies of discrete family symmetries in the minimal supersymmetric standard model ( mssm ).   we find that the gs cancellation conditions can be satisfied if the kac - moody @xmath1 levels are nontrivial, and that the ordinary unification of gauge couplings is not consistent with the tautomeric gs conditions for the non - abelian baryon number and lepton number symmetry in the monte carlo model using the see - saw mechanism. to test the existence of a low - energy non -Abelian discrete family symmetry at low energies, we consider the case of an anomalous@xmath3, and then we extend the cancellation mechanism to the cases of anomalous @x math3, @x Math4, and @x maths5.    we find no evidence for the existence or existence of any other such discrete family asymmetries at low energetic levels.
we present a new method for the description of non  equilibrium electronic environments in nanostructures.   the key idea is a systematic expansion around the classical path in order to obtain a langevin equation for the oscillator, which gives rise to non  trivial effects such as effective oscillator potentials and non  linear friction coefficients leading to both positive and negative damping @xcite. at the simplest level of this approximation ( neglecting quadratic fluctuations around the diagonal path in the reduced density matrix of the oscillators ), the coupling to the electronic non  equilibriated environment causes non  negligible effects including effective oscillation potentials, effective friction coefficients, and coefficient of variation. by combining exact solutions of the electronic system with a semi   classical expansion, together with an adiabatic approximation for the dynamics within the feynman   vernon influence functional ( double path integral ) theory, we revise this method, which has first been used for simple nan electromechanical systems ( nems ) models by mozyrsky and co   workers, and extend it to allow for the characterization of a relatively large class of non - equilibrium electronic reservoirs.
localization of a photonic mode by disorder in a statistically uniform and isotropic medium has been studied for more than two decades  @xcite, both in the optical and microwave spectral ranges. in this paper   we propose and demonstrate a new mechanism for disorder induced strong three dimensional ( 3d ) localization of light in planar microcavities ( pmcs ), containing a layer of strain - induced self - assembled quantum dots ( qds ).   it is shown that the shape of the photoluminescence ( pl ) spectrum emerging from the cavity is quite sensitive to the size of the excitation spot. if the size is sufficiently small, the pl spectrum becomes very narrow, in marked difference with the broad shoulder predicted by the standard basic cavity physics. if there had been no disorder, the experimental conditions of our paper would have resulted in an extremely narrow pl peak.the significant broadening of the spectrum, as observed in our experiment, is due entirely to disorder.    the broadening occurs both towards frequencies below and above the cavity frequency ( localized and resonant photonic modes, respectively ).
the origin of cosmic rays from the supernova remnant ( snr ) is still unknown.   we performed a deep exposure observation with @xmath0-@xmath1 to determine whether the x - ray emissions from the snr are diffuse or a group of unresolved point - sources, and found that the latter are more likely to be the main accelerator of the cosmic rays in our galaxy.
cepdal is a partially frustrated kondo lattice with a kondo temperature @xmath5.   it is an ising system with the magnetic moments aligned along the @x Math8 axis, as shown by the susceptibility measurements presented here. in this work   we present measurements of the magnetization, the electrical resistivity and the specific heat as well as experimental data from neutron scattering experiments indicating that the frustrated moments in cepdal remain fluctuating down to lowest temperature and affect the long - range order and magnetic excitations of the non - frustrated moments.
the @xmath2 lattice @xcite is a famous two - dimensional anti - ferromagnetic system presenting a spin gap and free from long range order.   the lattice may be considered as a realization of the shastry - s Sutherland model, which can be schematized as a square lattice, with@xmath5 anti - Ferromagnetic coupling between nearest neighbors, and diagonal anti -ferromagnetic interactions in one plaquette over two.the present paper employs two recently developed methods to study the phase diagram of this lattice.    the first is a self consistent pertubation ( scp ) method using a modified coupled cluster expansion for @x Math2 + 1/2 spins. by means of the renormalization group with effective interaction ( rsrg - ei )   it is shown that the cohesive energy obtained from the scp results agree with the results obtained from other studies. 	 the second is a renormalized excitonic method ( rem ) method based on the scale - change ideas inspiring the renormization group methods. erythroidal blocks of @x math2 + 2 sites are used to obtain the quantum phase transition between
non - locality in the nn interaction has not been the object of dedicated studies for a long time.   it is not absent however in models where it appears most often as a by - product of some prejudice in their construction. taking into account the substructure of nucleons and mesons in terms of quarks most often leads to a non - locality@xcite, which is better expressed in configuration space than in momentum one, contrarily to the above sources of non-locality. here  , we present the different non - local terms which we are interested in and show how they can be removed by a unitary transformation at the first order.. the third section is devoted to a few selected results concerning the deuteron : static properties, form factors, structure function and the tensor polarization. due to a lack of space, we concentrate here on the essential points.
the production of the @xmath0 vector meson from ultra - peripheral collisions ( upcs ) of heavy ions is a well - known phenomenon.   it is produced electromagnetically in distant interactions between two ions, and is accompanied by mutual coulomb dissociation. here  , we show that the cross section for @x Math0 production depends on the impact parameter of the hadronic interaction, and that the interferometer can be used to measure the effect of nuclear dissociation on the production of @x math0.
the formation of spiral arms in the galactic disk is a complex process.   recent work has suggested that spiral arms are transient structures, with their amplitude and pattern speed nearly constant with time. however, recently performed @xmath0-body simulations have shown that they are transient structure and alternate between formation and decay. here   we show that the mechanism of connection of wakelets is more complex than previously proposed by density wave theory. to address this issue, we present a new model of spiral arm formation in a pair of concentric rings in the disk plane using perturbers modelled as point masses, each of which induces local density enhancement around each perturber which we call'wekelet '. for each ring, we introduce a smaller number of perturters, and arrange them regularly in a series of concentricular rings in an elliptical plane in the galaxy plane. from these rings  , we find that there are two main processes of connection : ( 1 ) the first process of connecting wakelets and ( 2 ) the second process of linking wakelets. at the end of each process,   the two processes are connected by a single layer of gravity, which is called'wakelet '
an extended system of chemical systems is called extended if it consists of many individual similar subsystems distributed in space, and all the subsystems have the same dynamics.   an extended system is excitable if after being slightly locally perturbed from a stable steady state it returns to the quiescent state, but shows traveling activity waves if perturbations are large enough. here   we show that, in the extended system, wave trains, propagating solitary pulses and propagating pulse packets can develop when the initial conditions of a local subsystem are changed across the n - shaped nullcline of the phase space of a differential equation.we show that these types of wave patterns depend on the spatial distribution of the initial states of the desynchronized subsystems and the parameters of the local system.
the blue cluster in m31 is a highly - compact cluster of blue stars at the heart of the m31 double nuclear - cluster of old stars.   @xcite showed that this cluster in turn hosts the @xmath4 super - massive black hole also known to reside in the nucleus @xaicite. here  , we present new observations of the blue cluster obtained at the maximum angular resolution offered by the _ hubble space telescope _ to provide better constraints on the origin of the stars residing in this unusual environment.
a new methodology to the stochastic geometry modeling of millimeter wave ( mmwave ) cellular communications is proposed, which explicitly incorporates the empirical path - loss and blockage models recently reported in @xcite.   the framework is based on the poisson point process ( ppp ) and relies upon modeling the locations of the base stations ( bss ) as points of a homogeneous ppp, denoted by a point process. for the network deployment, the bss are assumed to be located at the origin of the cellular network and the mobile terminals ( mts ) are modeled as points within the ppp. using the slivnyak theorem, the network is modeled as a bi - dimensional downlink with a set of interfering bss acting as base stations and the other - cell interference as mobile terminal ( mt ) base stations.the coverage probability and average rate of the proposed framework are compared with those of the existing mathematical frameworks for modeling micro wave ( @xmath0wave ) and mmwave cellular networks.    the results show that the proposed approach is mathematically tractable for dense network deployments and uses a similar line - of - sight ( los ) ball approximation, but is applicable to medium /
the mass of the interstellar medium ( ism ) in galaxies is estimated from the optical depth of the submillimetre continuum dust emission from the galaxy.   this method is based on the assumption that the ratio of the gas - to - dust ratio is independent of the galactic radius and is the same in both the atomic and molecular phases of the ism. using herschel observations with spire and pacs, we find that the relationship between the sub millimetre optical depth and the gas column density of the atomic phase is not only independent of galactic radius but also of the chemical composition of the intergalactic medium, which is determined by the concentration of gas in the gas columns. for the molecular phase,   the relationship appears to be stronger than for the atomic one, but the gas mass is not affected by any of the other properties of the column density. when the gas becomes optically thin, the relationship breaks down and the value of the ` x - factor'between the two is lower than that of the bulk gas mass. at the same time, the values of the total gas mass are higher than those of the average gas mass in the entire ism, suggesting that the gas content of
the world that we see is full of structure.   although this structure seems obvious when we look at the world, providing a precise mathematical description has proven more difficult. here   we report preliminary results on the construction of a thermodynamics for the distribution of the probability distribution of images in small patches of the natural environment. using an initial data set of 45 images of scenes in the woods of hacklebarney state park in new jersey, we show that the spatial patterns of image intensity from reasonably natural environments have power spectra that approximate @xmath0, which is what one would expect from the hypothesis of scale invariance and simple dimensional analysis. by tuning the temperature to a special value @x Math6, the critical point which marks a second order phase transition between two different phases ( liquid and gas, ferromagnet and paramagnet,... )  , we find that the scaling behavior of the ensemble of images is not scale invariant, but is rather non  gaussian. as a result, we can generalize the temperature of the real ensemble to a family of ensembles indexed by a " temperature " and show that there is something special about the temperature ; if there is an analog
the bak  sneppen ( b  s ) model is an abstract representation of a biological system that evolves according to the darwinian principles of random mutation and natural selection.   it was introduced in @xcite in the context of self - organized criticality in systems with spatial interactions. despite its simplicity, the b   s model captures some of the features that are believed to be characteristic of evolving biological systems : it predicts evolutionary activity on all time scales with long periods of relative stasis interrupted by bursts of activities, referred to as _ avalanches. in addition to its usefulness in abstractly representing some key features of palaeontology and macro - evolution, the B  s model has also been employed to analyze the evolution of bacteria in a controlled, competitive environment. in this paper   we discuss the results of experiments that have been carried out to test the applicability of the b s model to the study of bacterial evolution.
identifying the nature of the dark matter ( dm ) remains one of the central unsolved problems in modern particle physics and cosmology.   a generic weakly interacting massive particle ( wimp ) is among the best - motivated possibilities since it can be thermally produced in the early universe in the right amount to account for the observed dm density, and many theories for physics beyond the standard model contain viable wimp candidates, as is the case of supersymmetry ( susy ) when the lightest susy particle ( lsp ) is the lightiest neutralino ( a linear superposition of the supersymmetric partners of the gauge and higgs bosons ) @xcite.. direct detection experiments are expected to greatly improve their sensitivity in the next few years and start probing interesting new physics at the large hadron collider ( lhc ). however, to prove that the newly discovered particles account for all ( or most ) of the dm in the universe, it is still difficult to establish whether or not it is the darkmatter.    we present a strategy for the search for dark matter by using the observation of dm annihilation radiation from the xenon-100 experiment, which has
theories with extra spacetime dimensions have attracted great attention for last years.   main phenomenological motivation, for considering such type of scenarios, was the new possibilities of resolution of gauge hierarchy problem @xcite-@xcite. among raised issues,   the actual task is to understand how to suppress neutrino masses in a needed level. due to low fundamental scale, the well known see - saw and scalar triplet mechanisms   do not lead to the sufficient suppressions. in this paper   we suggest mechanism, which provides generation of suppressed neutrinoid masses. within this mechanism, by introducing extended charged scalar multiplets in @xmath0, @x Math1 or @x math2 representations, neutrinos gain masses of a needed value.. proposed mechanism can be successfully applied also for low scale susy theories.
the idea that our universe is a brane living in a higher dimensional space has attracted considerable attention during the recent decade.   the physical properties on this brane must automatically be induced from the surrounding space known as bulk through some well - established junction rules. here   we present a solution to the problem of how to construct an appropriate bulk spacetime so that inflation driven by matter on the domain wall ( dw ) is induced from it. for this purpose, we choose our bulk metric to be @xmath3dimensional while the dw becomes @x Math5dimensional. using the double liouville type potentials in our model, we obtain an exact solution with quite generality to encompass new dynamics on the dw and serve our purpose well. among other things, we observed that our domain wall universe admits both minimum and maximum bounces.
in the present paper we study the quasi - linear interaction of proper modes of agn magnetospheric plasmas with the resonant plasma particles investigating the qld in the context of producing the soft and hard x - ray emission from agns.   we propose a model of the quasiexperimental mechanism of qld for the generation of synchrotron radiation in the magnetospheres of agns by means of the cyclotron instability induced by the doppler effect, which leads to the increase of the pitch angle distribution of the relativistic particles, and the consequent transmission of the radio emissions. under favorable conditions   this mechanism could also be efficient for explaining the mev - gev energy syn chrotron emission, strongly connected either with the submilimeter radio band, or with the infrared emission induced by an inverse - compton mechanism.
we present a systematic experimental study of forced imbibition of a model porous medium, consisting of a hele  shaw cell with precisely designed and controlled random variations in gap spacing, by a wetting silicone oil driven at constant flow rate.   the experimental results show that the scaling properties of rough interfaces are scale invariant on a mesoscopic scale, as a result of the interplay between ( i ) the stabilizing effects of the viscous pressure field in the fluid, and the surface tension in the plane of the cell, and ( ii ) the destabilizing effect of local fluctuations in capillary pressure, arising from the random fluctuations in gap spacings, on long and short length scales respectively.
magnetic fields are ubiquitous in diverse astrophysical settings on various scales ranging from proto - stellar discs, young stellar objects ( ysos ), microquasars, quasars and galaxies.   however, it is challenging to model magnetic fields realistically because of their complexities. using a composite singular isothermal disc ( sid ) model that is isopedically magnetized, we recently constructed global stationary coplanar perturbation patterns in a composite system of two fluid scale - free discs without magnetic field to generalize the work of shu et al. for a single isopedic sid and of lou & shen ( 2003 ) for a composite sid system with no magnetic field. here  , we further generalize these results by investigating the global axisymmetric stability of the global stationary perturbations in the composite system using a new set of global stationary magnetohydrodynamic ( mhd ) perturbational modes.    we show that the global stable profile of the composite sid can be defined as a continuum of growing normal modes while the global unstable profile can be described as a discrete spectrum of unstable normal modes based on the @xmath12criterion. when the mass - to - magnetic flux
the recent advances in interferometry have allowed the direct detection of pulsations in nearby cepheids ( ; ; ; ).   this result has opened the way for a _ geometric _ variant of the baade - wesselink ( bw ) method, allowing an independent distance measurement of pulsating stars, based on the interferometric determination of their radial pulsations. to achieve this,   the feasibility of the geometric bw method requires accurate predictions for the limb darkening ( ld ) of the pulsating star, necessary to convert the measured interferometer visibilities into angular diameters. in this paper   we present our time- and wavelength - dependent ld models, which are based on hydrodynamic simulations of the cepheid atmosphere, performed in non - lte conditions with a simplified radiative transfer using the complete set of atomic and molecular opacities provided by the atlas / synthe program. from the synthe emergent spectral intensity  , we derive the ld of the pulse star at a number of wavelengths and pulsational phases.the results show that the proposed model is more accurate than the other models, since the center - to - limb intensities
surface studies of the quasicrystalline surface of the decagonal and icosahedral   i  alcuco / alpdmn quasiahedra have been performed using scanning tunnelling microscopy ( stm ) and x - ray photoelectron diffraction ( xpd ).   the results show that the surface is a termination of the known bulk structure  @xcite, which is based on truncated pseudo - mackay icosahedra decorated essentially by bergman polytopes. in this work, using a combined experimental and theoretical approach, we show that these terminations are ordered in a decorated fibonacci sequence, and that the average density of terminations is 0.136 atoms per atom per plane as determined by dynamical low - energy electron diffraction analysis. to find the position of the terminations in the bulk model, we use a combination of atomic resolution stm images of the surface and autocorrelation measurements of the structural elements within the terraces and across steps on the surface with the geometric model @xcite for atomic positions of an f - phase. from these measurements   we find that the most stable terminations can be
the determination of the electromagnetic transition form factors ( tffs ) of light pseudoscalar mesons is of crucial importance for understanding the intrinsic structure of these particles.   it has been argued that the contribution of the hadronic light - by - light scattering to the anomalous magnetic moment of the muon, @xmath19, is one of the limiting contributions for the standard model ( sm ) calculation of this precision observable. here  , we show that the slope of the tff in the spacelike momentum - transfer region of a virtual photon coupled to a virtual vector meson and the external magnetic field can be determined by measuring the decay rate and dividing it by the quantum electrodynamics ( qed ) contribution. using a new model describing the @x Math20 transitions as a testing ground for models describing the@xmath20 transitions, which are needed to calculate the contribution from the hadronics to the anomalies of themuon, we find that the value of the total tff depends on the number of hadronic quarks in the mixed state of the meson. with the exception of the x - ray decay of the neutral meson, which is a pure su(3 )
we present a new approach to quantized quantum field theory ( qed ) using the canonical equal time formalism in the schrdinger picture.   we use an unconventional  empty " vacuum state to construct exact one-, two-, and three - fermion eigenstates of the hamiltonian, truncated to exclude states with free ( physical ) photons. by using the well - known @xcite formal solution of the maxwell equation, we reformulate the model using mediating - field green functions, in such a way that exact few - particle eigens of the resulting partially truncated hamiltonia can be obtained. for the case of a single fermionic field, we show that this approach is also applicable to two - body models in the scalar yukawa ( wick - cutkosky ) theory.
supersymmetric grand unified theories ( sgut ) have achieved some degree of success, but there are open problems that suggest the need to incorporate more elaborate constructions, specifically the use of higher - dimensional representations in the higgs sector.   this paper reviews the different mechanisms proposed in the literature to get anomaly free gauge theories for general gauge groups. focusing on su(n)-type models, we look for new alternatives to anomaly cancellation. using a set of lower - dimension su(5 ) representations with dimension @xmath1, we study the effect of the addition of high - dimensional higgs multiplets on the evolution of the gauge coupling from the gut scale up to the planck scale, focusing on models that invoke different sets of representations in order to satisfy the anomaly - free conditions. while the unification condition imposes some restrictions on the gut - scale masses of all the gauge bosons, gauginos, higgses, and higgsinos, the added multiplets do not change the unified gauge couplings, and neither modifies the unification scale. on the other hand,   the existence of anomalies at the quantum level is affected by the matter content of the model, thus the perturbative validity of
the measurement of the flavor non - singlet structure function @xmath5 in the proton by the nmc collaboration @xcite led to a surprising result.   the data revealed an excess of sea down quarks as compared to sea up quarks in the free proton, which contradicts the expectation of perturbative qcd ( pqcd ) predictions. here  , we estimate the effects of nuclear shadowing and antishadowing on the structure functions for the pair of mirror nuclei,@xmath1he and @x Math1h, and the difference between the two pairs in the region of bjorken @x maths2, where @x math2 is the number of baryon number sum rules constraint.    our results are compared with those of ref.  and show that the effect of shadowing is negligible for small values of b jorken # 2, but increases with increasing bjorksen#2 over the full range of bJorken_2. for larger values of Bjorkan_2,   it is much more pronounced. using the same approach, we also predict the gottfried integral for the @x
the diagonal representation of quantum states was suggested in @xcite.   it was studied and applied in the study of the entanglement phenomenon of multipartite systems. in this work, we present the explicit formulae realizing the connection between the diagonal and tomographic probability representations of quantum sates using the superposition rule for tomograms and in terms of weight functions of the diagonal representation where explicit kernels of the corresponding star - products are employed to obtain the addition rules for the tomograms ( symplectic tomogram ) and the weighted sum of coherent - state projectors of the density operator ( density state ) from the quantum state associated with the tomographic symbol ( called symp eclectic tomogram or tomographic - probability - distribution function ) as well as the density state in the diagonally represented quantum states. by means of the formalism of the star - product scheme  , we find mutual relations between the tomography - probability representation and the Diagramming of the densities of the quantum states within the framework of the discrete - time quasidistribution functions like the wigner function and the husimi   kano function. here, we focus on the formulation of the superpositions rule
whether spectral lines exist in the batse bursts is one of the most pressing issues in burst spectroscopy since no batse detections have been announced thus far.   we have developed a new line statistics methodology based on a hierarchy of probabilities based on the probability @xmath0 of detecting a line in a spectrum@xcite. using simulations, we show that batse and _ ginga_ are only marginally consistent in their ability to detect spectral lines.
the tibet air shower array has been conducted at yangbajing ( @xmath9e,@xmath10n ; 4,300  m a.m. ) in the northern sky for the first time using the imaging atmospheric cherenkov telescopes ( iact ) and extensive air shower experiments ( eas ).   the aim of the experiment was to perform an all - sky survey of the tev cosmic ray ( cr ) emissions from agns in the galactic plane in the longitude range from @x Math3 to @x math4.    the total number of sources identified by the eas experiments is expected to increase as the number of tev sources in the energy range of 20 mev to 30 gev  are increased due to the high sensitivity of the iact and the development of new techniques for detecting dim @x maths0-ray sources such as the milagrito / milagro @xcite and whipple experiment @xaite experiments. here  , we report the results of the latest update of the @xMath0-rays from the x - ray emissions of agns detected by the tibtet air showers array. among the
x - ray transient xte  j1550 - 564 ( galactic longitude and latitude @xmath0 ) was discovered by the all - sky monitor ( asm ) aboard the _ rossi x - ray timing explorer ( rxte ) on september 7, 1998 @xcite.   observations with the proportional counter array ( pca ) aboard #xmath1 were performed between septmber 7, 98 and may 20, 1999, during which xte / cyg  x-1 went through multiple canonical states. to obtain statistically significant results with the shot search technique in time domain by@xcite, sufficiently long observation and high source flux are necessary in order to suppress noise, thus limiting the application of the algorithm in other x -ray sources. in this work   we make energy resolved temporal analysis of xte * j15 50 - 664 with the data from the first observation performed just after the source was discovered and in the initial x - rays rising phase using the averaged superposed shot searching and analysis method.we present temporal and spectral property of averaged superposition shot, which has been studied in cyg  but almost no statistically significant result has been obtained
we study the effects of the constrained minimal supersymmetric standard model ( cmssm ), with strict universality at the grand unification scale, on the low energy cp   violation observables, especially @xmath2 and@xmath10.   we assume that the experimental bounds on the electric dipole moments of the electron and neutron constrained monte carlo conformations of the cmsms are at most @x math6.  in doing so, we take into account the experimentally observed branching ratio of the decay of the first generation of heavy sfermions to the higgsino dirac mass parameter ( @x maths4 $ ) and the trilinear coupling of the second generation of light sfer mers to the hgdsino Dirac mass parametrization ( @ xmath5 $ ). by taking into account all the relevant constraints, we show that the results obtained in the recent work @xcite can be extended to the more general constraint space of the larger set of cmssms, i.e., the 1st and 2nd generations of squarks for the first two generations of the super - quarks and the intergeneration mixing in the
we re - analyze the impact of the enhancement of @xmath4-elements on the properties of metal - rich stellar populations ( whose metallicity ranges from half - solar to three times - solar ).   the analysis is made for a particular choice of abundance ratios, for which self - consistent opacities are available. in particular, we start calculating extended sets of stellar evolutionary tracks, with total metal contents@xmath12, 0.019, 0,040 and 0.070 both for solar - scaled ( same abundance ratios as in the solar mix ) and @x Math4-enhanced patterns of abundances. based on those stellar models we derive large grids of isochrones and single stellar populations for which we present magnitudes, colours and mass - to - light ratios in many pass - bands of the johnson and wfpc2 photometric systems.
charged interfaces, which are topological configurations whether charged or not, provide a connection between the different ground states in quasi - one - dimensional systems, e.g. systems of weakly bound chains, via solitons which emerge as single particles, the @xmath6particles @xcite.   they can be defined as strings of reversed spins which, in the ordered broken symmetry phase, cost an energy proportional to their length because of interchain coupling. below@xmath12, a constant force is originated by confinement which binds the kinks into trains of @x Math4 particles, to recover the total increment of @Xmath8, within each chain. under the combined action of the attractive confinement force and the repulsive coulomb force,   the trains of kinks become mesoscopic complexes which span the whole sample at @x math13 and can be viewed as domain lines or walls. here   we present the general model of confinement based on the mapping of a system of interacting kinks to the anisotropic ising model. using both analytical and numerical methods  , we show that the experimental results are consistent with the theoretical model of the interaction between the two forces.
the metal - insulator transition induced by disorder in the problem of anderson localization remains poorly understood from a theoretical point of view.   the existence of a diffusive regime renders the concept of universality classes ambiguous in one dimension in that symmetry alone does not specify a universality class in this dimension. here  , we show that the crossovers between the chiral and the diffusive universalality classes can be computed quantitatively using perturbative techniques based on the so - called mesoscopic local density of states ( ldos ) which are known to be critical at the band center for the one - dimensional random - hopping problem but have not yet been computed for the weak on - site disorder problem. as a function of the number of hamiltonians in the ensemble, the ldos are either singular or diverging depending on the configuration of the hamiltonian and the distribution of the unitary operator for all realizations of the disorder. if there is a diffuse regime, it is possible to compute the crossover between the two types of monte carlo models by means of the following methods : ( 1 ) the use of nonlinear - sigma models defined in terms of quantum mechanics theory ; ( 2 ) the application
the stellar initial mass function ( imf ) has been traditionally interpreted to be an invariant probability density distribution function.   recent observational evidence has however ruled out this simple interpretation in that low - density regions have been found to be lacking the massive stars they ought to have produced given the large number of stars formed. a comprehensive theory, attempting to explain the evolution of the imf within galaxies is the so - called integrated galactic imf ( igimf ) theory. in the present paper   we re - interpret the simple models of chemical evolution with outflows and infall and consider again variations of the Imf between galaxies and within galaxies. using the galaxy - wide imf as a model, we find that the global abundance ratios of individual stars vary with the star formation rate and with the metallicity of the parent galaxy. for the global abundances of stars,   the differences between galaxies are mainly due to the effect of the different star formation rates on the global imf, whereas for the individual abundances they are mostly due to changes in the local imf. by taking into account the observed imf variations, we propose a new formalism of the chemical evolution of galaxies based on the igimF theory
combinatorial game theory concerns the computational difficulty in determining the winnability, outcome class, or value of game positions.   this paper covers games based on : arrays, sets, stacks, queues, priority queues, linked lists, and binary trees. for each of these topics,   we define the data structures, rulesets, and algorithms that are used to store them in the following categories : arrays ( arrays ), sets ( sets ), stacks ( stacks ), queues ( queues + lists ), priority queue ( priority queues ), linked Lists ( linked lists+lists ), binary trees ( binary trees ), and top - down lists ( lists + lists).we provide table  as a handy key to corresponding data structure, ruleset names, and section numbers.
in 2004, the wmap team implemented the gibbs sampling algorithm for the analysis of the cosmic microwave background ( cmb ) data from the cobe - dmr @xcite and wmap satellite missions.   this new method employs the gibts sampling algorithm to facilitate exact ( in the maximum - likelihood sense ), global and efficient analysis of even high - resolution data sets, and has been applied most successfully to the 3-year wmap polarization sky maps. here  , we take a small but important first step towards resolving these issues, by considering the marginal and conditional densities of the probability distribution @xmath0, which is the ensemble averaged cmb power spectrum, and the observed power spectrum of one given cmb realization. using this distribution as a kernel of the blackwell - rao estimator,   we show that it is possible to obtain a full likelihood approximation from the samples produced by the current gibbs sampler, and that the results are consistent with those of the experimentally observed data. while the proposed method is not perfect, it is at least as good as the state - of - the - art methods currently used in the literature.
the relativistic heavy ion collider ( rhic ) at brookhaven national laboratory is the first hadron accelerator and collider consisting of two independent rings.   it is designed to operate at high collision luminosity over a wide range of beam energies and particle species ranging from polarized proton to heavy ion, where the top energy of the colliding center - of - mass energy per nucleon - nucleon pair is @xmath0 = 200 gev. in the last few years  , data taken at rhic have demonstrated that the medium has created a strongly interacting hot, dense partonic medium with partonic degrees of freedom, the quark gluon plasma ( qgp ) in central au+au collisions at @x Math0 =200 gev  @xcite.. such matter is believed to have existed a few microseconds after the big bang. understanding the properties of this matter, such as the colored degree of freedom and the equation of state, is the physics goal of rhic and of broad interest. in this review   i will review the experimental results which were used to identify the existence of the hot, denser medium, followed by the measurements of its properties.
galaxy luminosity functions ( lfs ) provide a means of comparison between the populations of galaxies of various luminosities in different environments, and contain valuable information about the physical processes that feature prominently in galaxy formation.   we present observations of 25 groups of galaxies, and compute their luminosity function in the @xmath0 and @x Math1-band, splitting the sample in categories based on their x - ray luminosity. using toy - model simulations to qualitatively explain the differences in the lfs of x - rays bright and dim groups, we discuss the implications in the context of the evolution of galaxies in groups.
the breaking stress of neutron star crust is the maximum stress, as a function of strain, that the crust can support.   it is known that the durability of the crust at a given stress is known to depend on the temperature and, of course, the applied stress ( e.g., @xcite ). in the present paper   we extend these results with extensive molecular dynamics ( md ) simulations of breaking stress at different temperatures and strain rates. for most terrestrial materials the durability ( time before breaking ) of the breaking stress @xmath3 at a particular stress depends on the heat and/or temperature. for neutron star material the durability @x math2 is also dependent on the pressure and the strain rate. using the zhurkov model of strength, we show that the strength of the neutron star outer crust is very strong and that this strength is not just a constant, defined by the matter parameters ( density, temperature and composition ), but depends upon the duration of the stress  . however, the timescale of the process of interest is much longer than possible for direct md simulations. here  , we use this model to estimate the breakage stress for timescales of 1 s  1
the rise of the proton - proton cross section ( total, inelastic ) as the interaction energy increases is an important feature of the strong interaction picture.   the question how fast do cross sections rise is still a matter of debate..the original glauber paper @xcite was published over 40 years ago and it appears that since then some misunderstandings have arisen. rather complicated equations for scattering cross sections can be simplified significantly applying some additional assumptions  of limited validity. in this paper   we compare results of calculations with and without mentioned simplifications.    we will shown that there is quite significant difference between them.
the inert higgs doublet model ( ihdm ) is a very simple extension of the standard model ( sm ).   it predicts the existence of a neutral scalar field, denoted generically by @xmath9, which is the lightest odd particle ( lop ) in this model and will play the role of dark matter ( dm ) candidate. here  , we review the recent data on the couplings of this higgs - like particle to the gauge bosons and sm fermions. from the most recent measurements,   extraction of these couplings seems to be consistent to a great extent with those of the sm higgs boson couplings at the large hadron collider ( lhc ). moreover, data collected both at atlas and cms indicate that this new particle has zero spin and is cp - even, i.e. _@xmath5 is preferred @xcite.
the determination of the mass content of dwarf spheroidal galaxies ( dsphs ) is a fundamental step for our understanding of their formation and evolution.   this is particularly true for small systems such as dwarf spheroids, whose total mass can determine their destiny as being fragile objects, strongly perturbed by supernovae explosions and/or interactions with the environment, or mostly undisturbed objects. here   we report the results of a two - component modelling of the sculptor ( scl ) dwarf sphenroidal galaxy, using extended photometry from the eso/2.2 m wfi and vlt / flames spectra of hundreds of individual red giant branch ( rgb ) stars embedded in an extended dark matter ( dm ) halo to determine its mass content. when modelling scl as a one - stellar component system, which is based on the traditional jeans analysis of the line - of - sight ( l.o.s. ) velocity dispersion profiles, we find that it contains two distinct stellar populations with different spatial distribution, metallicity and kinematics : the metal rich ( mr ) stars are more centrally concentrated and show colder kinemics than the metal
dwarf irregular ( dirr ) galaxies are the largest number of galaxies in the present day observable universe.   they occupy the low mass, low luminosity tail of the galaxy luminosity function, and have low metallicities. unlike larger spiral galaxies, where stars dominate, in dwarf galaxies stars and make up the baryonic mass content on an equal footing, with little or no neutral atomic hydrogen ( h@xmath0 ) being traced through co observations. in this paper   we address the vertical distribution of neutral atoms in four dwarf irregular galaxies, and determine the scale height of the gas as a function of radius analytically. for each galaxy, we model the galaxy as a gravitationally coupled system of stars and gas subjected to the external force field of a dark matter halo, and use the model to obtain the vertical scale height as a functions of galacto  centric radius for four dwarf galaxies.    we show that the original two  dimensional partial differential equations can still be written as one  dimensional or ordinary differential equations, as in the case for the giant spiral galaxies which have flat rotation curves. by taking into account a rising rotation curve, we find that the size of the
we present experimental results obtained by the femtosecond time - resolved magneto - optical kerr effect ( moke ) on gd(0001 ) films to analyze the magnetization dynamics in the bulk part of the film, which we compare with the surface sensitive second harmonic generation ( shg ) signal.   we find pronounced differences during the first 2  ps which we attribute to transfer of spin - polarized carriers between the surface and bulk parts of the gd film. moreover, we study the fluence dependence of the demagnetization process and compare it with predictions based on the two - temperature model.
we investigate the transition from phase locking to noise - induced synchronization among uncoupled limit - cycle oscillators driven by common gamma impulses, which can be smoothly interpolated between regular periodic and random poisson impulses.   we show that the two types of synchronization dynamics are clearly different in many aspects, e.g. their stability, fluctuations, and statistical dependence on the driving impulses. as the statistics of the gamma impulses are varied, the synchronization dynamics of the oscillators becomes more complex, and the time constants of the synchronous states are longer than those of the phase locking state. when the impulse source is a common gamma - distributed impulse, the frequency detuning of the synchronized oscillators due to impulsive driving is reduced, while the temporal fluctuations of the lyapunov exponents are increased. however, when the parameters of the impulse sources are different, such as the timing of the pulses, the frequencies of the synapses, or the amplitude relaxation times of thesynchronized states, the lag time between the impulses, the differences in the phase distributions, and information - theoretic measures are not significant.
we study the poincar map associated to a periodic perturbation, both in space and in time, of a linear hamiltonian system.   the dynamical system originates from a model of stellar pulsations previously introduced in @xcite for low mass stars ( @xmath13 ) and extended to intermediate mass star (@xmath15 $ ). here  , we show that this map is an area preserving map with an oscillating rotation number function. in spite of the system being a perturbed hamiltonia,   it exhibits the typical features of a generic class of nontwist area preserving maps ( apms ), such as reconnection and meandering, with the nongeneric scenario of creation of vortices.the nonmonotonic property due to the triplication bifurcation is shown to be different from that exhibited by the cubic hnon map, which can be considered as the prototype of apms, and which undergoes a triplications followed by the twistless bifurancation.
we investigate the effect of inhomogeneities along the line of sight to a type ia supernova ( snia ) on the cosmological parameters of the @xmath0cdm model.   we choose four different approximations to probe these effects : the dyer roeder ( dr ) approximation, the weak lensing approximation with uncompensated density along the lines of sight, the flux - averaging approximation, and a new approximation which takes into account the different expansion rates along the Line of sight. in our analysis, we find that the mean magnification of the snia depends on the matter density and expansion rate along the beam. for the dr approximation,   the mean magnitudes are shifted by a non - negligible amount due to the strong lensing of large - scale structure, while for the weak lenses and the flux-averaging approximation the changes are not significant. using the new approximation, we show that the temperature anisotropies of the cosmic microwave background ( cmb ) and baryon acoustic oscillations ( baos ) are significantly larger than those of the first - year sloan digital sky survey ii ( sdcs2k2 ) and the salt2 light curve fitter.
the critical temperature of a superfluid fermi gas of fermionic atoms in the regime of quantum degeneracy is @xmath0. to obtain such high critical temperatures a strong coupling mechanism is required, forcing the theoretical description to extend beyond the standard bardeen - cooper - schrieffer ( bcs ) approach.   we have focused in detail upon a related yet distinct approach @xcite, which is to significantly increase the interatomic couplings by making use of a feshbach resonance and to study the effects of these couplings on the critical temperature at all detunings from the resonance. in this paper  , we present a functional analysis of the crossover behavior of the two - particle interactions in a resonant system using a finite temperature field theory that accounts for fluctuations as well as the full energy - dependent scattering t - matrix. with the help of a renormalized renormalization procedure, we show that the transition temperature of the superfluid gas from bcs to bose - einsteinian condensation ( bec ) superconductivity is determined by the existence of a population of tightly bound composite bosons within the crossover regime where the interaction between fermions and fermion pairs
this paper addresses the problem of interacting electrons in a band of a two - dimensional crystal.   this problem uncovers all the macroscopic properties of the materials of which the maximum interest is centered at the present on the high-@xmath1 superconductors, in particular, on the nature of their normal state. to fix ideas and to fix some notation let us review the highlights of the problem.
supersymmetry ( susy ) is currently the most attractive theoretical framework describing physics beyond the standard model ( sm ).   if it is realised at the electroweak ( ew ) scale, many of the superparticles should be discovered at next generation hadron colliders, such as the tevatron ( run ii, @xmath5 tev ) at fnal and the large hadroncollider ( lhc,@xmath6 tev)at cern. however, these machines, while having the chance of being the first to access the susy domain, are hampered by the fact that a large qcd background and the lack of knowledge of the initial centre - of - mass ( cm ) partonic energies render difficult the task of determining sparticle properties ( masses, couplings, quantum numbers, etc. ). in this paper  , we consider the scope of electron - positron linear colliders ( lcs ) in accessing some r - parity - violating signals of susy. using the most general supersymmetric extension of the sm incorporating susy ( mssm ), we show that lcs can be used to probe the effects of the baryon
the relative fluxes of the stronger emission - lines of the narrow - line - region ( n ) of active galactic nuclei ( agn ) can be successfully reproduced assuming that the main excitation mechanism of the n is photoionization.   we use the hii region abundances derived in previous works to infer that of the non - photoionized n and constrain, via a grid of photoionisation models, the average physical parameters of the N. the results are compared with the results obtained from the long - slit spectroscopy of the extended broad - line region ( e.g. ngc  3281 ) of seyferts and the nuclear ( n=180 ) regions of active galaxies.    the results show that the n- and n-emission - line ratios vary with the distance from the nucleus of the galaxy to the source of the gas, and the effect of shock velocities below 300  km  s@xmath5 is more pronounced in the n than in the e. g. n. the chemical abundances of the two regions are not significantly different.
we present here some results obtained by the pronaos balloon - borne submillimeter experiment ( programme national dobservations submillimtriques ) on orion and m17, two star - forming molecular clouds.   we show that the temperature and spectral index of the dust grains in these clouds vary from 10 k to 80 k, the coldest dust being in the outskirts of the star - formation complex, mainly in the form of cold ( early protostellar? ) clumps. for orion,   the temperature is about 10 k above the equator, and for m17 it is about 80 k. the latter is a giant molecular cloud, with a diameter of about 2.5 m and a mean mass of about 1.5 g. the intensity contrasts between the two clouds are enhanced by the presence of low - temperature dust at the edge of the cluster.
the idea of small - world networks has become extremely wide - spread in modern - day scientific and popular thinking.   many networks have been classified as " small worlds "  @xcite, ranging from social acquaintance networks through technological ones to networks in biology. here   we show that a network is a small world if the average distance between nodes is at most a logarithm of total system size. for networks where neighborhoods of nodes grow according to a power law rather than exponentially, average distances also grow as a power of system size rather than its logarathm. since a powerLaw growth in neighborhood size is a discrete analogue of fractal growth  @xxcite ( i.e., an exponential growth in the size of neighborhoods ), we call this the  fractal / small -world dichotomy.  on the other hand, for networks with strong geographical constraints, such as power grids or transport networks, even long - range connections are constrained by euclidean distance, and hence can not give rise to true small-world behavior.
abstractgalaxies experience the most dramatic changes during galaxy mergers.   the origin and evolution of angular momentum in different types of galaxies are not well understood. to empirically assess the role of mergers on the evolution of rotation, it is necessary to know the intrinsic distribution of rotational angular momentum of stable disks, before a galaxy undergoes an interaction. here  , we use integral field spectroscopy ( ifs ) data from the atlas@xmath3 and sauron surveys to investigate the origin of slow rotators in a cluster galaxy sample that is predominantly early - type and gas deficient. using the tully - fisher relation, we show that the rate of rotation of the core of the cluster galaxy is proportional to the number of stars in the cluster, and this relationship is stronger for the cluster with a large number of fast rotators than for those with small rotators. by contrast, the radial velocity dispersion of the cores of the clusters with slow rotator galaxies is much smaller than that of the ones with big rotators, which suggests that the process of rotation is more rapid in the group with fast rotations. based on our results,   we propose that the origins of slow
the aim of the present work is to give observational constraints to better understand the dynamical evolution of open clusters ( ocs ).   the main result of our study is the observation of a mass segregation in ngc 6231, which is a rich and very young oc : it has an age of 3 - 4 myr and contains more than one hundred o and b stars. as the age of the cluster is nearly one order of magnitude smaller than its mean relaxation time ( @xmath0 )  , we conclude that the observed mass segregation is an imprint of the stellar formation processes. however, the preceding conclusion is dependent on the physical validity of the _ mean _ @x math0. from the observational point of view   we have to observe not only very young or extremely young ocs but also clusters with ages of the order of their crossing time or below. in such clusters   relaxation processes have no meaning and the observed locations of the stars are close to their birthplace.    the authors show that the position of massive stars in the center of rich young clusters can not be due to dynamical mass segregation. for producing a trapezium - like system within just a few crossing times, the
we present first detailed observations of fine - scale chromospheric phenomena in the sunspot s umbra using h@xmath1 imaging spectroscopy data obtained with the new solar telescope ( nst, *???   * ) that operates in big bear solar observatory.   the data allowed us to fully resolve ubiquitous dynamic umbral jet - like features in the chromosphere above sunspots and measure their general properties including their temporal resolution, spatial distribution, and dynamics. from the data set we show that the repeating dark half - parabola feature seen above 1  mm is a propagating front of penumbral waves that are excited at the umbra - penumbra boundary ( x=1  mm ) and travel toward the outer bounds of the penumumbra. for about 3  min the tip of the spikes appears to be rising up with velocities of about 4 - 5  km s @xmath0, which is expected to reflect local sound speed and is in the range of the reported velocity associated with oscilaltions and shock formation.. after @x Math5  min they briefly appear nearly every three  min approximately at the moments
the exchange bias ( eb ) effect, which takes place at ferromagnetic - antiferromagnetic ( fm - afm ) interfaces, has been widely investigated in the last decades.   however, several aspects of this effect have not been completely elucidated, especially the assessment of the magnetic structure at the interface and throughout the volume of the afm layer@xcite. here   we show that the coo structure is extremely influenced by the substrate, through the epitaxial strain and interface chemistry, as well as by the growth conditions. on pt(111 ), coo films are ( 111 ) oriented, and a moir pattern can be observed according to the oxidation conditions and thickness of the deposited layer @xcite ; on pd(001 ), the film morphology is ( 111)/ir(100 ) with a wurtzite - like coo bilayer at the surface. for coo / sio@xmath6/coo / mgo multilayers,   the monoclinic transition from bulk to paramagnetic phase is accompanied by a shift of the hysteresis loop of the fm layer due to an intrinsic exchange bias field ( @x
in standard models of stellar interiors, radiation zones which are convectively stable are postulated to be without motion other than rotation.   but various observational results ( i.e. surface abundances, helioseismology ) show that these regions are the seat of mild mixing, and the most likely cause of such mixing is the differential rotation, which drives a large scale meridional circulation due to thermal imbalance and angular momentum transport and gives probaly rise to shear instability. in this work  , we have undertaken to improve the modeling of the transport of angular momentum by internal waves by introducing the effects of the coriolis force on the rotational profile of the radiative interior of the sun. for the case of weakly differential shellular rotation,   the wave frequencies of the region where the waves are excited by turbulent convection are strongly influenced by the rotation because their frequencies are of the same order that the inertial frequence, @xmath0.    indeed, the low - frequency internal waves which are responsible for the deposit or the extraction of angular kinetic momentum are gravito - inertial waves. as a consequence, the action of the rotation on the waves and their feed
we report the first time that full temporal coverage has been obtained of a caustic crossing at such high spectral resolution.   we show that the changes in the equivalent width of the h@xmath1 line observed during our vlt fors1 spectroscopic monitoring of the k - giant source star of are qualitatively consistent with those expected from stellar atmosphere models for a star of this type ; the @xmath0four - day duration of the second causic crossing is also consistent with theory.
the evolution of the chemical composition of intermediate - mass agb stars is studied using synthetic evolution models, which include the latest input physics.   the results show that the observed abundance anomalies in the surface of evolved stars with initial masses between 3 and @xmath0 and with metallicities@xmath6 of 0.02 and 0.005 are due to a combination of mixing inside convective zones and non - convective mixing processes. for each other stellar mass, full evolutionary models were computed up to the fourth " full amplitude " thermal pulse in the so - called " asymptotic regime ". from these models,   synthetic evolution was then used to follow global surface properties and nucleosynthesis up to planetary nebula ejection. at the end of their life, stars of low- and intermediate -Mass evolve along the asymptic giant branch, where they experience recurrent thermal instabilities and substantial mass loss. during this phase  , the stars undergo a very rich and unique nucleosynthetic process, which is supported by the observed abundances of newly synthesized nuclides on the surface.
the local time characterizes the time that a sample trajectory of a given stochastic process spends in the vicinity of an arbitrary point.   the local time can be expressed in terms of the squared bessel process, which is a well - known property of the gibbs operator. here   we derive a local - time representation of the bloch density matrix, i.e., the matrix elements of the Gibbs operator, and show that it can be used as a viable alternative to the commonly used feynman   kac representation for extracting both large and small - temperature behavior. by means of the replica trick  , we obtain a heuristic version of the path integral with respect to functionals of the _ local time _. using the one - point distribution of the local times, we show that the simulation of the interaction between the two functions of the  local time  and the   gibbs operators is computationally feasible and that the latter can be represented by a local time analogue of the salam formula.
ultraluminous x - ray sources ( ulxs ) are point - like non - nuclear sources in external galaxies with apparent luminosities greater than the eddington limit of stellar mass black holes.   we have obtained a moderate - resolution long - slit spectrum of a ulx in ngc  7331 , a highly - inclined, i = 77@xmath8 @xcite, sa(s)b spiral galaxy subtending 10.5 on the sky. as part of a program of spectroscopic studies of the local envrironments of ulx candidates, we have studied the optical emission features of this ulx candidate using a combination of optical imaging and spectroscopy. to our knowledge, this is the first report of an ulx within the @xmath9 isophote of the _ chandra _  field of ngc7331  in the h  ii region of the ~30  pc range of the supernovae at the center of a bright blue emission region in which the ulx is located.    we model its spectrum as emission from a young star cluster combined with a nebula photoionized by a cluster hosting an X - ray source.
the dissipative dynamics of a small system coupled to multiple baths is studied using linear response theory following the approach presented in @xcite.   our model comprises of a particle, with generalised coordinates in a one dimensional harmonic oscillator potential with angular frequency @xmath1, connected to two baths comprising of four quartic oscillators each. for each bath,   the system is in the integrable regime and the environment has very little effect on the system's behaviour. when the systems are in the chaotic regime, the system behaves dissipatively and the equilibrium energy value is@xmath20.    we also carry out numerical simulations and compare the theoretical results with those obtained from simulations.
the tachyonic nature of the neutrino was proposed in the 1980s @xcite, and once one accepts the conception of the tachyon, it would be natural to expect a number of different tachyons with various masses.   yet, today we observe only single particles, neutrinos, which potentially could be a superluminal tachyon. in this work   we show that only very light ( < 1 order of magnitude lighter than the electron ) tachesons can be classically stable in a variety of rotating gdel - like cosmological backgrounds. by analyzing the spectra of scalar and dirac fields in the expanding and rotating universe, we find that the threshold of instability occurs at a tiny mass which seems to be too small to provide superlominality of the standard model particles. here, we generalize this result to a more realistic situation of expanding, rotating universe and make estimates for the upper bound of tachlon s mass from the current upper bound on the rotation rate of the universe and the hubble constant.
the pseudogap regime of the cuprate superconductors is characterized by the presence of a cornucopia of phases, particularly on the underdoped side of the phase diagram, which appear in particular materials and for certain values of the doping level, temperature, magnetic field, etc.   near half - filling, the hubbard model, the @xmath3 model, and generalizations of these appear to have many phases which are nearby in energy @xcite. if the interactions between them are sufficiently strong compared to their effective kinetic energy, then they will form an ordered lattice ( which can be stabilized by a crossover to 3d order if there are many@xmath2 chains coupled together ) of defects and the charge density wave will become incommensurate with the lattice.. however, this can not continue indefinitely if the ddw state is stabilized by approximate nesting, since the fermi surface ( fs ) would eventually move away from the nesting wavevector. in this paper  , we consider various ways in which @x Math0-density wave ( ddw ) order can go incomensurate.    we also discuss the reasons for expecting ddw order to occur in
we investigate the cross - market correlations between returns of stocks traded on two large but geographically distant markets : new york stock exchange and deutsche brse.   our objective is to identify the strength of the instanteous as well as the time lagged dependencies between evolution of these two markets. in the first step  , we present a brief construction scheme of an asymmetric correlation matrix and a short description of basic properties of the ginibre orthogonal ensemble ( ginoe ). in this work   we show that the ginoe matrix can be diagonalized to obtain spectra of their eigenvalues and eigenvectors which are homogeneous and assume a regular elliptic distribution of the eigenvalue spectrum. in order to test the results of the diagonalization, we compare the results with universal predictions of the adequate, wishart ensemble of random matrices. for the stock market data,   the results show that there is a non - zero probability that at least some of the observed eigen values and eigvectors are real. however, for the de Deutsche brse data, the results are not consistent with the wishart predictions.
the determination of the composition of h  ii regions is a challenge that has consequences on our understanding on the chemical evolution of our universe.   we present photoionization models for the califa survey of h - ii regions obtained with the cloudy code driven by pycloudy, and show that these models predict the 4363/5007 line ratio to be close to ( and a little bit smaller than ) the observed values from the observations.
in the field of hadron physics, the study of in - medium properties of mesons and nucleon resonances carries the exciting promise to find signatures for partial chiral symmetry restoration at finite baryon density and temperature.   photoproduction of @xmath8 mesons off nuclei by the cbelsa / taps experiment at mami @xcite and for energies up to 1.1 gev at kek@xcite is dominated by the s@xmath4(1535 ) resonance from beryllium onward @xcites.    the experiments do not cover the full line shape of the r@x Math4(1440 ) resonance, but it is found that the second resonance bump, the excitation region above the @x math5(1232 ) resonance bumps, is completely suppressed for all nuclei from bryllium onwards @xcitite. however, total photoabsorption does not provide information about the behavior of individual resonances. a significant in -medium modification of the d@x maths6(1520 ) resonance   is predicted due to the strong coupling to @xMath7 while only small effects are expected for the p@
we propose and evaluate the ir photodetectors based on the van der waals ( vdw ) heterostructures with different numbers of the active undoped graphene layers ( gls ) placed between the emitter and collector and separated by the inter - gl barriers ( glips ).   the effect of the insertion of the inner gls, which provides the extra electron photoemission and capture, can lead to a dramatic increase in the detector responsivity. as shown in this paper, the effective electron photoescape at far - ir range is much smaller than that for the qws in the quantum - well infrared photodenitors ( qwips ) since doping of the outer gls leads to the inclusion of the electron - electron scattering mechanism of the capture into the gls. however, the detection responsivity of the glips increases with the number of gls in the heterostructure due to the photocurrent gain associated with the redistribution of the electric field in theheterostructure and leading to amplification of the emission from the electron injection from the emitting electron.
the lhcb experiment records millions of proton collision events every second.   most of them are not needed for further analysis and are discarded by a sophisticated multi - layer trigger system @xcite. what is left amounts to @xmath0 events in run 1. before physics analysis takes place, the number of events is further reduced by a factor of around 10. at the end of the stripping process,   the data is divided into several streams. among the streams,. events that passed the stripping processes are indexed by event index.    the web interface for event index is available at http://www.eventindex.cern.ac.uk.
a ground penetrating radar ( gpr ) is used for detecting buried objects in the subsurface and detecting non - metallic scatterers with increased sensitivity to dielectric contrast.   a variety of signal processing algorithms have been proposed for detection of low metal - content landmines in realistic scenarios ; approaches based on feature extraction and classification are found to be the most effective, yet false - alarm rates remain very high. in this work, we propose employing dictionary learning ( dl ) to improve the performance of a gpr - based landmine classification algorithm using real data from l - band gpr. by using the coefficients of the resulting sparse vectors as input to a support vector machine ( svm ) classifier to distinguish mines from clutter, we show that odl outperforms k - svd in terms of speed and low false-alarm rates.
the nonequilibrium green s function method is a generalization of the fourier s law for heat transport in electronic transport, with fermions replaced by bosons as basic entities.   the method is applied to one - dimensional ( 1d ) chains, benzene rings, and carbon nanotubes using the nonlinear interaction formalism. here  , we give a brief introduction of the method, emphasizing on both the theoretical formulation and computational implementation. at the first step,   we introduce the green s functions, including the contour - ordered ones, and discuss the equations of motion of the greens functions, feynman diagrammatic expansion, and dyson equations. then, we discuss the heat current and derive a formula for effective transmission when there are nonlinear interactions. after the introduction of this method, we present results of 1d chains, benzo[2,3-dimethylbenzene ring, andcarbon nanotube simulations, and review some of the interesting features in such systems.
the near - infrared ( nir ) period - luminosity ( pl ) relationship of cepheids has been extensively studied in the past.   the largest difficulty in achieving good - quality nir pl diagrams for cep heids is the necessity of obtaining well - covered light curves to compute the mean magnitudes. here   we present a new method for recovering mean @xmath5 magnitudes from single - phase observations using template - fitting procedures.    the method uses statistical relations between fourier amplitudes and phases of the @x Math3 and @x math4-band light curves, which are then used to reconstruct the latter into a series of @x maths3 and@xmath4- band template light curves.. the obtained residuals are then fitted by a function depending on the ~3 phase of the light curve ; the error of the method is estimated to be as low as 0.05 mag.  also, the correction functions for each bandpass are computed, and the results are compared with those of previous methods.
cell adhesion is an essential element of many physiological situations, including development, tissue maintenance, wound healing, angiogenesis, and cell migration.   the behaviour of adhering cells is strongly influenced by the chemical, topographical and mechanical properties of the surfaces they attach to @xcite. during recent years  , experiments with elastic substrates have shown that extracellular elastic properties are also highly relevant for cellular decision making. in this contribution, we discuss several modelling efforts which in the future might be integrated into such a systems - level understanding of focal adhesions. among them, we start with a discussion of integrin signaling at focal adhesion and how it relates to the spatial and temporal organization of cells.. next we describe a simple model for the stochastic rupture dynamics of adhesion clusters under force, which quantitatively demonstrates that the internal state of adsorbed cells can be regulated by force. finally we introduce a new model ( _ two - spring model _ ), which shows in a quantitative way how extacellular elasticity might modulate the build - up of intracellular force at focalAdhesion.
the asymptotic quasinormal modes ( qnms ) of massless scalar field in the modified schwarzschild spacetime from the planck scale corrected spacetime named as gravity s rainbow have been investigated by using the monodromy method.   the results show that, when the plank scale modification of spacetime is taken into account, the asym ptms depend on not only the mass parameter of the black hole but also on the initial configuration and the quantum effects of the spacetime.
the large aperture of the _ james webb space telescope _ ( _ jwst _ ) will provide new opportunities to study comet dust, gas, and nuclei at moderate and large heliocentric distances ( defined here as beyond 3  au ), and at excellent spatial resolutions for closer objects.   moreover, the telescope s operational strategies, scheduling, and instrument capabilities allow us to follow comets over a wide range of times and helioclentric distances. in this paper  , we highlight some of the observational challenges, experimental techniques, and representative science opportunities that _jwst_ offers as a tool to improve our knowledge of comets.. we then propose four science examples that _ jWst _ will be especially suited to address : ( 1 ) the ability of the telescope to measure the primary drivers of comet activity : h@xmath0o, co@x Math0, and co. ( 2 ) simultaneous observations of water gas and dust comae and how they can be used to assess nucleus heterogeneity ; ( 3 ) the use of high - resolution near - infrared spectroscopy to investigate the chemical composition of comae ; ( 4 ) the utility of the observatory s fine
the neutrinophilic two higgs doublet model  ( @xmath4thdm ) is a new physics model where neutrinos are regarded as dirac fermions.   the model is extended to include a dark matter candidate in the loop diagram involving a dark - matter candidate at the one - loop level and a neutral neutrino at the tree level. by extending the model, we show that the new vacuum expectation value  ( vev ) of the neutrinophile scalar field which is relevant to the dirac neutrinophilic properties of the model can be explained by a suppression mechanism for the soft - breaking parameter of the global@xmath2 symmetry.. the new vev is generated via a mechanism that the interaction of neutrines with the standard model   ( sm ) higgs boson is generated using a loop diagram including a dark- and/or neutral particles.
ultraluminous x - ray sources ( ulxs ) are a new type of extragalactic x - rays.   they are connected with nebulae and are frequently located in bubble - like nebules.. the nebula sizes are from 20 to a few hundred parsecs. here   we compare the gas nebula around ss433 with neBulae of ulxs in holmberg ii, ngc6946 and ic342 galaxies observed recently by the integral - field spectroscopy methods. using the russian 6-m telescope with the integral field spectrograph mpfs @xcite, we find that the ulxs have about the same size, the same line luminosities and about the exact same total energy budget. for the first time we observe the existence of an edge - on star in the supercritical accretion disk of ss433, which is surrounded by a radio nebula w50, which was produced by the relativistic jets of the ss433 star.    the main difference between ss433 and other known ulxs is highly supercritical and persistent mass accretion rate ( @xmath1 ), which has led to the formation of a super
the @xmath0dor stars constitute a new class of pulsating variables that was discovered only recently.   we already performed a systematic detection and classification of these stars from the hipparcos periodic annex using the geneva photometric system. here  , we report our analyses of the obtained data from the new photometric data. in sect.3, we search for periodic behaviour in the data. on sect.4, we present the spectra of the stars. in Sect.5, we end with some conclusions.
we have completed a survey of 54 local spirals @xcite using the hubble space telescope imaging spectrograph ( stis ).   this data has been used to make primary super - massive black hole ( smbh ) mass estimates by modelling the gravitational potentials and surface brightness profiles of the host bulge. however, the low mass end of the relations ( @xmath5 ), which essentially represents late type spirals, has yet to be fully populated. here   we present an atlas of our data so far including radial velocity fields, major axis rotation curves, stellar velocity dispersion fields and aperture integrated velocity dispersions ( curves of growth ) from the first integral field spectroscopic survey of a sample of spiral bulges.
we prove that the neumann laplacian on the geodesic triangle @xmath0 in the hyperbolic plane has no nonconstant ( square - integrable ) eigenfunction.   we further develop the method of ` asymptotic separa- tion of variables'that we introduced in  to study real - analytic eigenvalue branches in situations where a geometric domain degenerates onto a lower dimensional domain. for all but at most countably many@xmath40,1,   the lebesgue measure is zero and the set of sets of angles @x Math19 for which the hyperBolic triangle with angles @Xmath20 admits a nonconstants laplace eigenfunctions has lebesgeusgue measure zero and is contained in a countable union of nowhere dense sets.
the post - recombination era is a period of intense research in the field of pre - biotic molecular formation.   it is usually supposed that the first objects ( first stars or galaxies ) could be formed from a gas cloud by the gravitational attraction. since the primeval gas does not contain heavy elements like carbon, primordial molecules such as @xmath0,@xmath1 and @x Math2 are good candidates to lead to an efficient cooling of the primordial gas.. the role of molecular cooling in the fragmentation of primordial gaseous clouds is important because the excitation of the rotational levels of these molecules induces a cooling which can trigger thermal instability in the collapsing cloud. in this contribution,   i will present the formation ofprimordial molecules and discuss how these molecules can influence on the second generation of molecular formation, which will be important for biomolecular formation.
we introduce an opportunistic network decoupling ( ond ) scheme for the @xmath0 channel with interfering relays in a practical multi - source interfering relay network.   the scheme adopts the notion of the multiuser diversity gain for performing interference management over two hops and is based on the scheduling strategy presented in time - division duplexing ( tdd ) two - hop environments with time - invariant half - duplex ( hd ) relays, which is a more feasible scenario than the conventional @x Math0 channel in  @xcite.. the scheme is applied to the @Xmath0 channels with one additional assumption that @x math2 _ half - Duplex ( s  d ) relaying nodes interfere with each other. by using the ond scheme, we show that the optimal degrees of freedom  ( dof ) in the@xmath1-user interference channel can be achieved by using orthogonalize - and - forward relaying, which completely neutralizes interference at all destinations if @x maths2 is greater than or equal to @xMath4. in the second - user interference channel,   it is possible to achieve the optimal dof
in the context of string theory, brane models are interesting from both phenomenological and cosmological viewpoints. in the previous discussions,   it was concluded that thecosmological production of monopoles and domain walls is negligible in the brane model. in this paper, however, we reconsider the formation of these structures and show explicitly how they can be formed by the branes dynamics.   we have constructed defect configurations, which induce the shift of the center of the localized matter fields in the localized space to form the cosmologically formed defects. in our model, the defects are described by branes that have less than three spacial dimensions in the uncompactified spacetime. in order to explain the baryon asymmetry of the universe  , we have extended the defect branes between branes using a sphaleron - like brane configuration. when the proton lifetime is reduced to a few seconds, the polarization of the local matter fields is induced by the excitation of the defected branes.
this paper is a detailed version of my preprint @xcite, which was written about five years ago.   it is dedicated to the memory of my teacher vladimir abramovich rokhlin, who suggested to me, a long time ago, in 1977, to develop a theory of real algebraic knots as a topic for my second dissertation ( after phd, like habilitation ). following this suggestion  , i moved then from knot theory and low - dimensional topology to the topology ofreal algebraic varieties. however, problems on spatial surfaces and plane curves were more pressing than those on spatial curves, and my second doctoral dissertation defended in 1983 was devoted to the constructions ofReal algebraic plane curves and spatial surfaces with prescribed topology. here   i discuss the main points of this change in the topic : ( 1 ) the traditional techniques of classical knot theory used in knot theory use plane knot diagrams, i.e., projections of knots to the plane ; ( 2 ) the projection of an algebraic curve is algebraic, but the projection contains extra real points, which do not correspond to real points of the knot ; ( 3 ) there is a forgetting functor
the anisotropy of the cosmic acceleration observed from the observations of type ia supernovae ( snia ) @xcite has been investigated in several cosmological models, including the vector dark energy model with cpl parametrization.   although this method optimizes the statistics due to the large number of supernova in each hemisphere, it has lost all information about the detailed structure of the anisotropic component. in this paper  , we use the hemisphere comparison method to investigate the cosmic accelerations in different parts of the whole sky, and study the possible existence of anisotropies. to do it, we take use of the union2 dataset@xcite, and divide them into 12 parts according to their positions in galactic coordinate system. among them, six regions are useless and masked in the investigation due to a lack of super Nova data. in each unmasked region, we study the cosmic accelerating by taking the deceleration parameter @xmath0 as the diagnostic, and find the significant difference for different regions. using healpix as a probe, we extract the lowest multipole components, i.e. monopole and dipole, in this anisotide map
the factorization approach ( fa ) based on the non - relativistic qcd ( nrqcd ) represents a reliable framework to study heavy quarkonium production and decay processes @xcite.   the fa implies universality, i.e. the values of long distance matrix elements extracted from different experimental data sets must be the same. however, due to the presently rather large theoretical uncertainties@xcite and the unknown size of higher twist process contributions @xxcite the existing experimental data do not allow yet to check the fa universality. in this work   we investigate the effect of spin effects in the production of different charmonium states at high transverse momenta by using the nrQcd factorization method. for each state,   two opposite sign double spin asymmetries are observed : the first is caused by the contribution of the quark - antiquark color octet intermediate states to the cross section of the production process, and the second by the interaction of the gluon fragmentation into the hadronization state which is responsible for the reduction of the dark quark mass. with the exception of the transition from the hadronic state to the light quark state, the opposite
high index surfaces of si have been the subject of intense theoretical and experimental investigations.   however, the high index surfaces have not received nearly as much attention as the low index ones. in this article, we present a study of the adsorption of br on the si(211 ) surface by scanning tunneling microscopy ( stm ) and low - energy electron diffraction ( leed ) using a @xmath1 surface reconstruction technique. to our knowledge, this is the first study to use stm and leed to reconstruct the @x Math1 surface of a stepped si(212 ) surface. at the same time, the results of leed and stm studies on the reconstruction of the clean surface of si(210 ) surface are discussed.
cd@xmath1 t cell responses exert strong selection pressures on human immunodeficiency virus ( hiv ).   the selective pressure exerted by these responses has been quantified from the growth rate advantage of viral mutants that escape cd@x Math1 + t cell control. in this study, we investigated under which circumstances genetic interference arises and how it affects the interpretation of escape rate changes in systems with two loci. to this end, we developed a virus dynamics model, in which viruses possess multiple epitopes and can escape from cd#@xMath1 t cells directed against them.. the model builds on well - established work @xcite, and is stochastic to describe mutation, extinction and fixation of virus strains adequately, and allows recombination of viruses.    we found that interference emerges mainly when cd@Xmath1+t cell responses coincide and are similarly strong, but only in system with a high level of stochasticallyity. if the virus population was sampled more often early than late, the escape rate decrease would be more pronounced.
we construct a theory of active slender bodies, by modeling them as filaments that enforce slip velocities or non - equilibrium stresses at the fluid - structure boundary.   our theory isolates the specific microscopic details of self - actuation in the boundary conditions, from which universal, macroscopic fluid flow can be generated through a bead - spring discretization which replaces the continuous filament by a chain of spheres connected by non - linear springs. within the springs,   the spheres produce spontaneous hydrodynamic flow while the springs penalize changes in filament length and filament curvature. for each spring, the sphere is assumed to be an active filament with a diameter so large that brownian effects are negligible. using this theory, we show that the fluid flow of the active slender body is proportional to the sum of its angular and linear momenta, and that the elasticity of the filament is proportional on the basis of the friction between the filament and the fluid.. the model is tested on a series of examples of slender bodies capable of spontaneous motion in viscous fluids, including microtubules driven by molecular motors, axonemes, cilia, flagella, and their synchronization and metachron
we consider the problem of online update of a pareto archive composed of mutually non - dominated solutions when a new candidate solution shows up.   this problem is commonly used in multiobjective metaheuristics ( momhs ), e.g.multiobjective evolutionary algorithms, whose goal is to generate a good approximation of the parenchyma of the arabidopsis front. for most of the nowadays momhs,   an external archive of potentially efficient solutions is used to update pareTo archive containing solutions not dominated by any other solutions generated so far. in order to speed - up the process of updating a preto archive some authors have proposed the use of specialized data structures and algorithms, i.e. quad - trees. however, the results of computational experiments reported in the literature are not conclusive and in some cases such data structures may in fact increase the update time compared to simple list. in this paper   we revisit the issue of updating paredto archive with a new solution @xmath0 using paracic local search ( pls ) method. as a result  , we show that it is possible to quickly update paresto archive from a set of
we investigate the relativistic jet expansion of gamma - ray bursts ( grbs ) in the soft x - ray band of grb 970228.   we find that the jet beaming factor for each burst is @xmath8, and that the decay light curve steepens from a bulk lorentz factor of @x Math6 to @x math7 as the jet expands from the time when the observer can " see" the entire jet, leading to a faster rate of decline in the luminosity. at the same time  , the break time in the afterglow light curves is predicted to be between 1 and 25 d. these results are consistent with the observed redshifts of ~0.433 to 4.5 d. we also find a break time of ~1 d, which is within the upper limit of the break times known to exist for grb s.
microfluidic devices such as micromixers, dna amplifiers, chromatography systems, or chemical reactors are increasingly being used for the manipulation and transport of fluids.   however, in order to fully understand the properties of such devices and to optimise them for efficient usage, some fundamental questions in physics including the behavior of single molecules in fluid flow or the validity of the no - slip boundary condition have to be answered. here   we review the recent advances in our understanding of the slip phenomenon which is a fundamental question in fluid mechanics.
a polyakov loop is widely used in order to know whether a system is in the confinement phase or not.   we consider prescriptions that remove the dynamical quark loops which directly screen the color fields from apolyakov loop.    we assume su(3 ) lattice gauge theory with single quark - flavor and single quarks.. the qcd partition function is expressed as @xmath6,\end{aligned}\ ] with @x Math7 a ( lattice ) dirac operator, in which non - zero chemical potential can be introduced, and @x math8 $ is the gauge action. 	 the fermionic determinant can be expanded in terms of two types of quark Loop ; ordinary quarkloop and wraparound quark loop. for each type of loop,   the first type is an ordinary loop, whereas for the second type it is a wrapper loop. both types of loops are responsible for the confinement properties of qcd at zero and finite chemical potentials. by taking into account the fact that the behavior of the quark dynamics is encoded in the same force field, we show that the confinement property is independent of the direct charge - screening effects
the goal of hadron physics is to provide a quantitative explanation of the properties of hadrons through a solution of quantum chromodynamics ( qcd ).   this is a fundamental problem that is unique in the history of science because it presents a challenge to the standard model of quantum field theory, which is based on a poincar invariant quantum non - abelian gauge field theory with elementary excitations that are not those degrees - of - freedom readily accessible via experiment ; i.e., those that are confined to the quantum universe. here  , we review recent progress in the study of mesons using the complex of dyson - schwinger equations ( dses ) as a powerful tool to study confinement and dynamical chiral symmetry breaking ( dcsb ), and their impact on hadron observables.
we investigate the influence of the network topology on the dynamics of epidemic spreading in a metapopulation model of the susceptible - infected - susceptible ( @xmath5 ) reaction - diffusion process.   we find that the curing rate of individuals inside each network node is a function of the degree of the local node, i.e., it is not dependent on the local property of theNetwork node, such as the degree @x Math1.    this observation is robust to the change of the size and the average network degree, and is consistent with the results of previous studies using a simple strategy, where @x maths1 denotes the node degree and @x math2 is an adjustable parameter. 	 interestingly, we found that epidemic explosion can be suppressed at a certain value of @xMath4, which corresponds to an optimal strategy to suppress epidemic explosion. to place the finding on a solid foundation  , we have also performed a mean field analysis, wherein the epidemic threshold@xmath6 is identified as the onset point where the global healthy state with no infected individuals loses stability.
the leading model of gamma - ray bursts ( grbs ) involves a relativistic fireball jet, where the observed gamma rays are produced by radiation from fermi - accelerated electrons in optically thin shocks.   we investigate neutrinos arising from protons that are accelerated in the reverse shock of a supernova while the relativism jet is still propagating inside the star. using a type ib progenitor as our model star, we show that protons can be accelerated to @xmath0@xmath1 gev in thereverse shock.    the low and high - energy protons produce mesons efficiently by proton - photon and proton-/proton - proton interactions, respectively, and these mesons are suppressed by the high proton and photon densities in the shocked jet. for energies in between, cooling mechanisms are faster, and result in a characteristic suppression feature in the meson spectrum. however, we still expect a reasonable number of neutrino events. within this range, we find that the most common event is a gas - like burst with a choked jet that is dark in gamma rays and bright in neutrines.. the second event is likely
it is a commonly accepted hypothesis that buoyancy force drives planetary and stellar dynamos.   however, the validity of this convection driven dynamo model has recently been questioned in certain cases, such as ganymede, mercury and mars, or the early moon, and alternative dynamo mechanisms, based on a different forcing, thus seem needed. here  , we investigate the dynamo effect of the elliptical instability ( ei ) excited by tides in a rotating sphere using global simulations of the basic flow of an incompressible newtonian fluid of density, kinematic viscosity, conductivity, and permeability, enclosed in a sphere of radius @xmath5, rotating with angular velocity@xmath2.    we first solve the hydrodynamic problem, in order to describe the tidally forced basic flow, and then the flow resulting from its destabilization by the ei when the body force is strong enough ; then, we add in the kindyn the magnetic field into the problem, discarding its back - reaction on the flow. finally, we tackle the self - consistent dynamo problem by solving the fully coupled magnetohydrodynamic equations. for each case, we
we present a new tool for the search and measurement of gravitational waves from inspiraling compact binaries.   the tool is based on the well - known technique of matched filtering, which relies on the fact that an accurate model can be constructed for the expected signal. in this paper  , we focus on certain issues related to the search of gravitational wave signals from inspiraled compact binary systems. among these issues   are the use of the fitting factor as a measure of template imperfection, the ambiguity function for the detector noise, and the detection limit of the source signal.
the first aspect of perturbative quantum field theory ( pqft ) is the study of amplitudes with many legs and a low number of loops ( zero or one ).   the complexity of the amplitude saturates when the number of external particles exceeds the dimension of space - time. in this article   we show that the simplicity of the results can be understood in a geometrical language : the amplitudes are volumes of tetrahedra in  depending on the masses and momenta  spherical or hyperbolic geometries. for @xmath6 external particles in lorentzean dimensions one obtains a unified hyperbolus interpretation of the one - loop amplitude if one works in euclidean instead of lorentzingan space-time. for these external particles by momentum conservation the external momenta sum up to zero, and their vectors span an (@xmath3)-dimensional tetrahingedron ( in three dimensions they are the sides of a triangle ), in four dimensions they form a cycle of four edges that spans a tetrachedron ( where geodesics are straight lines ). from an experimentalist point of view   these results are vital for
a monte carlo simulation of the white dwarf populations in our galaxy is presented.   the simulation models the complete galactic content of white dwarfs and post - agb stars, including all four stellar populations, thin disc, thick disc, halo and galactic bulge ( the latter not of relevance here).the simulations are based on the model of the galactic structure presented by. a recent analysis of the macho project of microlensing events in the magellanic clouds attributed to white Dwarfs @xcite and a deep proper motion survey for high - velocity white dwarbs by appeared to confirm a high density of white dwarves in the galactic halo.. however, the results have been criticised by and, but open questions remain. if the initial  mass  function in the early phases of galaxy formation was as top heavy as claimed by some high redshift investigations ( e.g.  2005 )white dwarfs could be responsible for an important fraction of the milky way mass budget.
the equilibrium phase coherence and vortex order in the fully frustrated xy model on a honeycomb lattice of josephson - junction arrays and superconducting wire networks with a triangular pattern of nanoholes ( @xmath3 ) described by the monte carlo ( mc ) model of the system are studied using the parallel - tempering method ( exchange mc method ).   this method is shown to reduce the long equilibration times in glassy systems, which have been shown to be associated with the frustration parameter@xmath2, which sets the average density of vortices in the lattice between the pinning centers. at nonzero temperatures,   no evidence of an equilibrium order - disorder phase transition or even a spin / vortex - glass transition is found for either the ground state or the low - temperature state in the thermodynamic limit. however, the correlation lengths of the phase and vortex variables are found to increase linearly with the system length, which is consistent with an equilibrium zero - temperature transition, where the critical temperature vanishes.
we analyse the transition from regular to weakly turbulent motion in high symmetric navier - stokes flow at realistic truncation level using continuation of periodic orbits and computation of lyapunov exponents.   we find that a cascade of quasi - periodic doubling bifurcations occurs in the transition to weak turbulence, which is characterised by a fixed frequency ratio of the bifursating tori in the limit of a perturbation parameter to zero.    we propose a model ordinary differential equation ( ode ) for this cascade based on a fixed time smooth suspension of the hnon map, which displays a complete cascade with a fixed frequencies ratio of each doubling point in the range of @xmath1 to zero in the case of a slight perturbance in the model ode.
we investigate the effect of finite sampling rate corrections on the coefficients of diffusion models defined by eq.   (  \,,\end{aligned}\ ], for any integer @x Math16, in the it - langevin form of the fokker - planck differential equation. to test the validity of the empirical access to unknown drift and diffusion coefficients of stochastic processes, we derive expansions for the conditional moments up to some specified low order of @x maths21, directly from a generalization of the poisson - bellow model of the time evolution of pdfs, namely @x math21 + \frac {k = x }    0.1}{\rangle|_{x_t = x}.   the obtained results are compared with the original coefficients, which are obtained from the finite estimation of the coefficients using the first order approximation
the isotopic composition of the hg and pt isotopes in a sample of nine high - density molecular ( hgmn ) stars has been studied.   the results show that all stars have overabundance of hg by more than 5  dex compared with the solar abundance. for five programme stars with extremely sharp spectral lines ( @xmath8  km / s )   we find that the most pronounced deviation from the terrestrial isotopic proportions is found in the star hr  7775, which is nearly pure hg at 3984   . however, the other stars show a wide range of isotopic compositions, ranging from terrestrial mix to nearly pure pt. these anomalies are analogous to those found for hg, in the sense that the heavier isotopes tend to dominate in cooler stars.the main purpose of the work reported here was to provide additional observational constraints to guide the theorists in the understanding of the isotopic anomalies in hGmn stars, improving upon previous studies through the much better data quality obtainable now.
quantum information transfer in spin chains is a promising approach for the realization of quantum computers.   however, the fidelity of quantum information transmission is gradually degraded by the dispersion effects associated with the quantum propagation. to overcome this problem, we introduce an adiabatic transport scheme assisted by a slowly moving external field applied to a spin chain. using gaussian wavepackets as initial states,   the quantum population of spin excitation is transferred from one end of the spin chain to the other end under certain conditions when the external field is moving slowly. here  , we show that this scheme is highly robust, can be operated rather fast ( in the absence of disorder, it may be as fast as one tenth of the natural propagation speed ), and offers a number of advantages : ( i ) it is very robust to static disorder, ( ii ) it can be easily stopped and relaunched, ( iii ) the time of arrival of the quantum state transfer to the last spin can be predicted with high probability, and ( iv ) it has a low cost.
the experimental search for supernarrow dibaryons ( snds ) has been ongoing for over 20 years.   the aim of this review is to summerize the experimental attempts to look for them so far. in the first part of the review   we consider the results of experiments carried out at the proton beam of the linear accelerator of the inr using the two - arm spectrometer t1/2 and t2/3 with proton beams from the jinr phasotron at an energy of about 216 mev, where a six - quark state with deuteron quantum numbers can be formed by an interaction of a meson or another particle with a quantum number with the same as that of the metastable state.the results of the experiment @xmath24 show that the production of dibyrons with exotic quantum numbers is possible in the process@xmath25 but the nature of the observed state is not fully understood. in our previous studies   it was shown that the decay widths of the decoupled dibyons into two nucleons are larger than 1 mev ; however, these results are based on model calculations of very limited predictive
we give some results for the dependences of the number of interacting nucleons and the multiplicity of produced secondaries on the impact parameter.   these results are based practically only on geometry, and do not depend on the model of interaction. in the case of minimum bias interactions   the discussed dispersion of the distribution on the numbers of interacting nucleus is very large, which allows in principle to have a significant dependence of some characteristic of the interaction, say, mean multiply of the secondaries, on the used trigger. on the other hand, in the cases of central collisions the mentioned dispersion is small that should result in weak dependence on any trigger. by considering the high energy nucleus - nucleus collision as a superposition of the independent nucleon - nucleon interactions,   our results can be considered also as a test for search the quark - gluon plasma formation.
superconducting qubits are solid - state artificial atoms that exhibit a spectrum of energy levels, tunable via an external control parameter.   these states can be coupled to a large - amplitude harmonic control field, and resonantly driving the artificial atom with a harmonic field can couple and induce quantum - state transitions. here  , we present three experimental works that utilize landau - zener - stckelberg ( lzs ) transitions in a strongly - driven superconducting persistent - current qubit for quantum interference interferometry between repeated Lzs transitions. using amplitude spectroscopy, we observe quantum interference fringes in n - photon transition rates between repeated lz s transitions in the qubit, and we show that the quantum interference can be leveraged to facilitate non - adiabatic quantum control.
one of the most fascinating results of modern theoretical physics is that, in a large class of models, the finite - size scaling often reveals more information about the system in question than the bulk result itself.   this is most apparent in the study of full counting statistics ( fcs ) of charge transfer in systems with conformal invariance, where the ground state energy of the system per unit length of a system of length follows the relationship @xcite @xmath7 and the coefficient appearing in the term for the system size is the central charge of the nano - structure. here   we review this conjecture along with its background, and present the latest numerical evidence for the conjecture. in addition, we discuss more general questions about finite - time corrections to fcs, particularly with reference to the measurement of fractionally charged quasi - particles.
the turing mechanism is a diffusion - driven process that gives rise to spatially heterogeneous stationary patterns in the steady state.   the stability of the turing pattern is characterised by a stationary distribution of islands of high activator concentration in a sea of high inhibitor concentration. in this paper  , we study the formation of turing patterns in networks with a discrete structure and consider three different types of networks : regular, random and scale - free. using the coupled map model for the networks, we show that the dynamics of the reaction - diffusion ( rd ) processes, leading to turing instability, are closely related to the spatial distributions of the network nodes. at each node, the concentration of the activator and the inhibitor   is given by the concentration variables and the coupling matrix is symmetric with diagonal elements zero if the nodes are connected and is zero otherwise. under the same approximation, the time increment and the mesh size of the networks are reduced to 0.5 and 2.5, respectively. when perturbation is applied to the system through small local increases in the activators concentration, i.e., the activation rate, the removal rates and the cross - reaction coefficients, the equilibrium
we propose an anisotropic inflation model with the vector impurity.   this is the first concrete model which realizes anisotropy inflation, exits successfully to the isotropic standard universe, and provides a framework to discuss interesting phenomenology. in this paper, we analyze the system numerically and show that the anisotropical inflation is realized successfully. using the slow - roll approximation, we obtain degrees of the anesotropy. in section v, we discuss phenomenology of theAnisotropicflation induced by the vector Impurity. here  , we emphasize that the gravitational waves can be produced through the aniostatization of the spacetime.
a classical nova eruption plays an important role in the evolution of cataclysmic variable stars ( cvs ).   it represents the primary mechanism for mass - loss in these systems, preventing ( most of them ) them to end up as supernovae ia. still, the connection between the nova eruptions and the physical parameters of cvs is not very well known, mainly due to the fact that a large fraction of the post - nova systems remain unidentified @xcite. here  , we present the results of a systematic observing campaign in order to recover and study classical novae that erupted at least 30 yr ago ( earlier than 1986 ). by means of @xmath0 photometry, we identified potential candidates for the post-nova v1301 aql, v1151 sgr, v3964 sgr and v908 oph from the field of el aql and v606 aql ; the selected candidates were subsequently observed spectroscopically to confirm their identification via their spectroscopic characteristics ( mainly the presence of characteristic emission lines ). in addition, we also obtained spectrograms of candidates for other post -Nova systems that were included in@xcite
the coulomb phase of spin ice in a magnetic field applied along the @xmath0 $ ] crystallographic direction is studied using a mean - field theory ( mft ) designed to capture the distinction between confined and deconfined phases.   the method is applied to a simplified model of classical spin ice, in order to illustrate the general approach and its physical interpretation. for the first time, we show that the confinement phase transitions in spin ice are nonzero across the transiton, and that the magnetization may or may not change across the transition. by applying the method to a quantum model of bosons,   we find that the phase diagram generically consists of a set of confined phases at low temperature in which the magnetizations are, to a very good approximation, fixed. this plateau structure is strongly reminiscent of the lobes present in the phase diagrams of the bose  hubbard model @xcite, a connection that helps clarify the general phase structure.
the sloan digital sky survey ( sdss ; @xcite ) has proven to be an important resource for the discovery of new am cvn stars, with six new systems discovered so far.   we have now started an extensive observing program using an array of telescopes to uncover this ` hidden'population of am cVn stars. in this paper, we discuss the total sample of amcvn candidates we selected from the sdss, data release 6 and the strategy for spectroscopic identification of this sample. in section    we present the first new system found in this way, which is a binary consisting of a white dwarf accretor and a degenerate helium - transferring donor star that is characterized by a short orbital period below the orbital period minimum for hydrogen - rich donors.
the damping rates of low - energy excitations ( phonons ) in a spatially homogeneous bose - condensed gas at temperatures much smaller than the mean field interparticle interaction are determined by the szepfalusy - kondor mechanism.   this mechanism is based on the scattering of thermal excitations on the excitations through the damping channels of the phonon branch of the spectrum, which can be treated as landau damping. here   we present a new theory that takes into account the ground state of the inhomogeneous condensate and provides corrections to the self - energies of the bogolyubov quasiparticle excitations for the temperature range from 0.1 to 4.0 k. the latter are obtained by using the zero - temperature diagram technique, which allows one to find corrections proportional to the energies of these excitations, proportional to @xmath4, where@xmath5 is the density of the condensates and @x Math2 is the gaseous parameter. with the help of the beliaev method,   the corrections are found to be more accurate than the ones obtained by considering the interaction between the two excitations as
one of the widely studied model to describe network dynamics, barab@xmath1si- albert ( ba ), is based on preferential attachment mechanism.   according to this model, over time new nodes join system and link to the earlier nodes, with probability proportional to the degree of preexisting nodes. in this work,   a general approach to generalize ba model is proposed based on fractional calculus. in other word, the equation governing the dynamic of network growth is a non - integer order differential equation. hence, operators from fractions are no longer identical. by working in fractional realm, some nodes can face long time delays before jumping to the next time step. at the same time  , some other nodes experience very short waiting period and pass more time steps relative to the frozen ones.the proposed approach is tested on a simulated network based on citation and scientific collaboration network ( @xcite ) and world - wide web network ( #wswc ). as a result, the results show that the proposed approach works well in simulating both real and simulated networks.
spatial stochastic modeling is a tool frequently used to study biochemical reaction networks in cells where the spatial distribution of molecules is non - uniform @xcite.   the models considered when studying systems on the scale of a living cell are often divided into three levels : the macroscopic level, the mesoscopic level, and the microscopic level. here   we present a method to efficiently compute accurate reaction rates for the reaction - diffusion master equation ( rdme ) on unstructured meshes for a wide range of voxel sizes and for diffusion - limited reactions, thus facilitating accurate simulations of biochemical systems in complex geometries. using this method, we show that the common approach of simply scaling the bimolecular reaction rates by the volume of the voxels leads to inaccurate results for some systems, and that by instead following the approach outlined in this paper, the rdMe converges to the corresponding microscale results.
we study a lattice model of a system of hard straight rods of length @xmath0 on a square lattice.   we find very strong numerical evidence that the system shows nematic order at intermediate densities for@xmath11, and that there must be a second phase transition as density is increased. to the best of our knowledge,   this second phase - transition has not been discussed in published literature before.
charged massive particles ( champs ) can be long - lived in various extensions of the standard model of particle physics such as supersymmetry.   however, the abundance of such stable charged massive particles would be severely constrained from experiments of the deep sea water @xcite, in particular, from the decay of light elements synthesized by big bang nucleosynthesis ( bbn ). here  , we investigate the evolution of the bound states of some negative champs ( referred to as @xmath5 ) with some light elements by numerically solving the boltzmann equation and then we discuss the effect of the ( charged ) bound state on large scale structure and the damping of matter power spectrum.
the light harvesting complex ii ( lhcii ) of higher plants is the major light - harvesting antenna containing almost half of all the chlorophyll in the chloroplast.   its main function is to deliver excitation energy to the nearby photosystem ii ( psii ), and it is also implicated in regulated energy dissipation, the so - called non - photochemical quenching ( npq ) @xcite. here   we use single - molecule spectroscopy ( sms ) experiments to study the properties of the trimers of the l hcii using a disordered excitonic model of the nmr spectroscopic properties of this complex. by analyzing the ensemble - averaged spectra of the photo - induced fluorescence peak distributions and the peak distributions of the carotenoid trimers, we show that the rate - limiting step in the npq process is not only the increase of the temperature across the thylakoid membrane, but also the change of the chromophore orientation and distance from the center of the cell. for both processes,   the observed changes are explained by the disordered excited - state model, which is based on the crystal structure of the
electron scattering reactions with nuclei have provided the most detailed and complete information on nuclear and nucleon structure @xcite.   additional information is available from neutrino - nucleus scattering, which can give information on the hadronic weak current and on the strange nucleon form factors. in this contribution   we present relativistic models for the exclusive and inclusive electron and neutrinos scattering in the qe region using the distorted - wave impulse approximation ( rdwia ) to describe the exclusive reaction where the outgoing nucleon is detected in coincidence with the scattered lepton and the residual nucleus is left in a specific discrete eigenstate. in the inclusive reaction the outgoingucleon is not detected and the cross section is integrated over the energy and angle of the final lepton as well as the state of the residual nucleus. by taking into account the interaction mechanism of the probe with the quasifree nucleon that is emitted from the nucleus,   the model is able to show that the nuclear response is dominated by one - nucleon knockout processes, where the probe interacts with a quasiparticles that are emitted from an incident neutrineutrino with a direct one - step
the semi - emipirical pseudpotentials ( seps ) for wurtzite semiconductors, and more specifically gan nanowires, are derived from the density functional theory ( dft ) local density approximation ( lda ) calculations of a passivated and an unpassivated ( bare ) slab.   the seps are angular momentum dependent non - local ( or semi - local ) potentials that assume an empirical analytic functional dependence ( a sum of gaussians ) instead of being obtained from dft - lda and include only a local component. in this work   we have extended the sep formulation to wurtZite semiconductor nanostructures, particularly to gan, a promising nanostructure in the field of solar cells and optoelectronic devices due to the wide band gap of gan ( 3.5 ev ), that together with indium nitride, a narrow band gap semiconductor ( 0.67 ev ) can cover the full visible solar spectrum by a proper alloying. here  , we explore the effects of confinement in the valence and conduction band states close to the nanowire band gap and we discuss the influence of confinement
vy canis majoris ( vy cma ) is a very luminous cool hypergiant star with a high mass loss rate.   it is also one of the most important for understanding the kinematics of massive star evolution. here   we present a detailed model of the complex asymmetric distribution of material in the star s circumstellar nebula, based on our multi - wavelength hst / wfpc2 images and the interferometric maps of the oh and h@xmath8o emission. using this model, we show that the star is ejecting large amounts of gas and dust at a prodigious rate, and that the process is driven by magnetic fields and convection. to understand the mechanism of this process, we have used a combination of spectroscopic and optical techniques, including the powerful infrared source and the oh maser, to study the radial motion of the star and its associated nebula over a wide area of the nebula from a distance of about 1.5 kpc. as expected, the star undergoes multiple mass loss episodes, with the largest events occurring within the first few hundred thousand years of its evolution. during these episodes,   the star ejects large
grover s search algorithm  @xcite is a generalization of the original quantum search algorithm.   it is used to find a sought - after ( " marked " ) element in an unsorted database of size @xmath0, and it may be used to speed up the solution of many problems that would be offered by quantum computers, if and when they are built. in this paper   we study the case where the generalized grover iterate of  @excite is applied to a quantum register that is initialized in an arbitrary mixed state.    our study extends and corrects a result from  @incite.. the results show that the initial state is not a marked state, but some general pure state, which is a superposition of the marked state and the unmarked states. for each state,   the hadamard operation is imperfect, and the rotation angles of the qubits are shifted by different degrees of freedom. on average, the number of rotated qubits is reduced by about 1.5 orders of magnitude compared to the original state.
electron transport through dna is crucial for its biological functions such as the repair mechanism after radiation damage and biosynthesis.   the detailed understanding of the conduction mechanism of dna remains still an unsolved task. in this work we investigate the role played by static parametrical disorder and complex structural effects due to irregular deviations from the ordered helical shape of the double helix ( reflected in random arrangements of the positions of the bases ) with regard to the charge transport in dna using analytical and numerical methods from the theory of ( nonlinear ) dynamical systems in combination with the theoretical of ( linear ) disordered systems. a nonlinear approach facilitating the concept of polaron respectively breather solutions of the nonlinear lattice system when parametrical and structural disorder effects are taken into account   is used for the theoretical description of charge transport along the steric structure of the bent dna doublehelix.. the results show that the mobility properties of the polarons and breathers of the model are highly sensitive to the degree of disorder contained in the on - site energies and/or in structural arrangement of the helix.
the nonequilibrium version of the single impurity anderson model ( siam ) is considered to be one of the best studied strongly correlated models in condensed matter physics.   it exhibits rich physics already in equilibrium, such as the coulomb blockade and the kondo physics that have been observed in experiments. despite its apparent simplicity,   the Nonequilibrium siam has met some difficulty in treatingNonequilibrium phenomena.. a theoretical approach that can deal with the strong correlation effect in nonequilibres is still called for. in this paper  , we examine the second - ordernonequilibrium perturbation regarding the coulsomb interaction @xmath0 of the multi - terminal siam using a generic configuration where the ph symmetry is not assumed, and miscellaneous types of asymmetry of couplings to the leads and/or voltage drops are incorporated as a generic multi - terminus configuration. by comparing the results obtained by the quantum monte carlo simulation with those obtained by our calculations, we show that the latter approach provides a consistent picture concerning the behavior of the self - energy and hence the dot spectral function for the full range of frequency and bias voltage, within the validity of the second
the effects of spontaneously generated coherence ( sgc ) in the electromagnetically induced transparency ( eit ) and giant kerr effect ( gke ) @xcite are studied in the four - level of @xmath1-type and double@xmath2-type systems based on the generating function approach.   the effects of sgc are studied by changing the property of the vacuum, and/or extra driving fields, such as a dc field, a microwave field, or a laser field. for the two types of systems,   we show that sgc can improve the ability of the original eit and gke, also the photon statistics can be greatly affected and reflect the characters of different dynamics.
the automorphism group of the complex of curves on a nonorientable surface of odd genus is isomorphic to its mapping class group.   the purpose of this paper is to prove the following theorem : the natural group homomorphism, which is injective, is surjective for the punctured projective plane.
malin 1 is a highly unusual disk galaxy characterized by an enormous, high surface brightness ( hi  ) rich and extremely low surface brightness disk.   recent r - band data by moore & parker @xcite show an exponential disk extending out to 124 kpc ( scale length 53 kpc ). in the presence of a luminous central component, the rotation curve has the shape typical of the less luminous, " dark matter dominated" high surface bright galaxies. however, this rotation curve is very uncertain because of the low resolution of the observations. here   we re - analyze the hi  data with special attention for the beam - smearing effects and to make a new comparison with the luminosity profile. using the newly derived rotation curve, we find that malin 1 appears to be a normal, early - type galaxy surrounded by a huge, low - surface - brightness outer disk.
the su@xmath0-symmetric generalization of the standard su(2 ) hubbard model@xcite has been intensively studied theoretically.   the possible phases, their nature and the critical coupling where they appear have been studied in detail for two special commensurate fillings of the band, namely for half filling and @xmath24 filling. in the present paper   we try to establish under what conditions the umklapp processes can generate gaps in the charge or spin sectors, and when and how the translational symmetry is broken. to this end,   partly analytic, partly numerical procedures will be applied. by studying the oscillatory behavior of the block entropy, the corresponding peaks in its fourier spectrum, and their relationship to the known properties of the half - filled and @Xmath24-filled models  , we show that the ground state of the one - dimensional su(@x Math9 ) model can not be spatially uniform at least in the large-@x math9 limit. a trimerized state with gapped excitations already exists for @x maths29 already.    the length - dependence of the entropy of finite blocks of a long chain is
we investigate the effects of atom - atom interaction on the dynamics of a bose - einstein condensate in an optical cavity with a moving mirror and atomic gas.   the system is characterized by two - body collision of ultracold atomic ensembles trapped in optical cavities @xcite where the excitation of a collective mode of the cold gas plays the role of the vibrational modes of the moving mirror. for low photon numbers when the optical grating produced by the cavity optical field is very shallow, one can approximately restrict the dynamics to the first two motional modes @xcite. in this work   we consider the system in the low photon regime but will not restrict our treatment to the weak atom - electron interaction. in order to study the influence of the atomic collisions on the system dynamics we have taken into account the existence of several nonzero quasimomenta of the energy bands (aband transitions ) and also the scattering of atoms to the other bands ( interband transitions).the results show that the absorption of the light from the cavity leads to a broadening of the momentum distribution of the atoms due to the propagation of the s - wave scattering at arbitrary momentum values and also to
the proton polarization of hyperpolarized solid - state @xmath0xe has been enhanced by a factor of 0.1 to 2 on a bruker sy-80 m nmr spectrometer ( 1.87 t at 142 k ) at room temperature via cross - relaxation between dissolved hyperpolarsized gaseous @x math0xe and@xmath1h of the liquid benzene solvent, which has also been firstly called the spinoe by pines group@xcite.   this method yields the proton enhancement of 6 by comparison of that without optical pumping on the brukersy-80m nmr spectrum at 1.7 t.  in addition, the effect of low - field thermal mixing or hartmann - hahn matching condition on the proion polarization of @x Math0xe produced by spin exchange is transferred to the propto - proton of solid - State @x maths1hcl via spinoe without using low -field thermal mixing / hartman - haahn matching condition.    this method could be used to enhance the proron polarization of ~5 orders of magnitude in solid -state @xMath0xe by dissolving it in
billiards are simple yet nontrivial examples of systems that display classically chaotic motion.   of special importance are the sinai billiard and the bunimovich stadium since they are known to be completely chaotic. in this article   we want to extend previous calculations and compute the full lyapunov spectrum and the ks entropy for a self - bound @xmath0-body system with hamiltonian  h=_i=1^np_i^22 m + _ i < jv(|_i-_j| ), where@xmath2 is a two - dimensional position vector of the @x Math3-th particle and @x math4 is its conjugate momentum.    the results show that the system is predominantly chaotic.. the main source of chaos is defocusing, which is found to be stronger in the transversal directions than in the two - dimensionally focused ones.
we present measurements of dynamical correlations in the presence of random pinning in a system of lennard - jones particles ( @xmath1 particles ).   we find that the relaxation time of the system increases strongly with pinning, at fixed temperature, without any evidence of increased dynamical heterogeneity or co - operativity. using a new method of analysing four - point correlation functions in real space, we obtain both a dynamic correlation length and the strength ofynamical correlations for the systems studied in  @xcite. these results are consistent with the prediction of random first order transition ( rfot ) theory.
a leptonic model is proposed to explain the rapid variability of the emission of tev blazars.   the model assumes a spherical source filled with a tangled magnetic field and relativistic electrons that travel with relativistically velocity at a distance of less than 1 pc from the central black hole and is usually assumed to be homogeneous. in order to constrain the physical parameters of the source, it is important to analyse not only the emission observed at a given time but also the evolution of the emitted emission, especially during the periods of activity. here   we show that the synchrotron self - compton process ( ssc ) can be explained in the simplest possible way by taking into account the light crossing time effects ( lcte ) of the radiation field and the particle evolution inside the source. for each time point the source is slowly evolving, the emission level changes rapidly and the source becomes more and more inhomogeneous as the source activity increases. when the source does not change its emission level for a given period of time, the same amount of radiation is still received by the observer at the same time. however, if the source has a very rapid variability time scale, the intensity of
the spin - incoherent luttinger liquid theory of the single - particle green s function for a one - dimensional interacting electron gas is reviewed.   the response of the electron gas to a time - dependent spatially local potential is discussed, and the results of the recent work on the singular response of a non - interacting electron system due to a localized core hole are discussed. in particular, we focus on the role of the charge sector which is gapless at zero temperature in the spin - coherent regime of the system.
jets of hadrons are produced in ultra - relativistic heavy - ion collisions at the rhic experiment.   the high transverse momentum ( ) measurements of hadron production at rhic have revealed three different observations related to jet quenching : strong suppression of the inclusive hadron spectra @xcite, large azimuthal anisotropies with respect to the reaction plane orientation @xmathite, and strong suppression on the near - side of the back - to - back correlations for trigger and associated hadrons at lower energy. here   i will review the dihadron correlation measurements at high  at the top rhic energy ( = 200 gev ) and discuss the expectations from the lower energy = 62.4 gev run.
the @xmath2cdm model, which is essentially a homogeneous and isotropic friedmann  robertson   walker ( frw ) spacetime filled with both pressureless dust and a cosmological constant, fits very well the evolution of the observable universe from structure formation to the present accelerated expansion.   the possibility of deviating from such a simple yet effective model has been widely considered throughout the literature, by taking into account less symmetric backgrounds or by introducing less ideal matter sources. in the present paper   we work along these lines, by including in the dynamics of an expanding metric a nonequilibrium contribution to the equilibrium pressure of the fluid, in the form of a bulk viscous pressure. using a dynamical system approach, we describe the space of solutions of an expanded frw spacetime in presence of a double - fluid source : a pressureless Dust component and a viscous radiation component whose bulk pressure is governed by the israel - stewart s model ( nis ), presented for the first time in@xcite and further analysed in @xcite.we show that the results are not only consistent with the results of previous studies, but also with those of
disk encryption is one of the most important security measures for mobile storage media.   we propose sdms ( secure disk mixed system ) to solve temporal and spatial limitations of existing disk encryption methods. in this paper, we describe our disk encryption method based on sdms and analyze security performance of our system. using sdms,   data is encrypted with different key each time data is writen, because it encrypts plaintext using random data generated by prng ( random data from random data generator ) and then encryptsplaintext using its randomly generated key. as a result, it is easy to get keychain used to encrypt plaintext data, if third party succeeds to detect encryption key by attacking a data sector. in the next section  , we present a new disk encryption algorithm based on the sdms which is implemented in windows vista. here, we show that sdms can be used to protect data stored in disk by encrypting plaintext between two diffusers in succession, and then passing the data through two diffuser in succession and finally encrypting Plaintext using aes of cbc mode.
we investigate the scattering of a composite system from a target with interactions which have a very short range compared not only with the size of the system, but also with the associated wave - length of the projectiles. for that purpose  , we consider the case of two particles, interacting through a harmonic oscillator potential, which collide with an infinite wall.   we develop two different methods to solve the problem exactly, obtaining the wave - function as well as the s- matrix, or reflection coefficients, which give the probability amplitudes for the excitation of the different oscillator states. in particular, we compare the exact results of the two methods, which are based on the uncorrelated scattering approximation ( usa ) and the adiabatic approximation, and show that the latter is more accurate than the former.
the influence of magnetic field and rotation on the dynamics of core - collapse supernovae ( ccsne ) has been studied mostly in the regime in which the magnetic field is large and rotation is rapid simultaneously, i.e., the combination of the magnetar - class magnetic flux and the rotation that would produce millisecond proto - neutron stars has been assumed.   however, the effects of these factors on the explosion mechanism of ccsn have not yet been fully investigated. here   we perform a global simulation of the pre - collapse evolution of an ob main sequence star with the solar metallicity and the surface rotational velocity of @xmath8200  km  s@xmath9 at the zero - age main sequence ( zams ) using axisymmetric ( 2d ) and global ( 3d ) simulations to investigate the influence of the magnetic fields and rotation of the progenitors on the blast energy of the event. by combining the results of previous simulations with detailed neutrino transport calculations, we show that the initial magnetic field of the star can be amplified by differential rotation, which leads to a strong magnetic field that is then amplified by the formation of a pulsar rotation period
we study the possible deviations from standard cosmology in a scalar - tensor gravity ( st ) theory at the time of cold dark matter ( cdm ) freeze - out, focussing on weekly interacting massive particles ( wimps ) as the most natural candidates for cdm.   we find that the expansion rate of the universe can be modified by a factor of two in the past if the dark energy ( de ) equation of state differs appreciably from the one of the scalar equations of state of @xmath0 and@xmath1.. this deviation from standard general relativity bears potentially relevant consequences in all those phenomena which are closely dependent on the timing in which they occur.
quantum computing is one of the most important areas of research in the field of computer science today.   it is now well established that quantum computation can be realized in quantum two - level systems ( qubits ), and that the states of these qubits can be manipulated as coherent quantum states with high quantum coherence. here  , i review the current progress in the development of quantum computers for quantum computation in the solid state, and discuss two proposals that are currently on the table : a loss - divincenzo proposal based on the spin degree of freedom of a single electron confined to a localized orbital state and a k+-induced confinement of a quantum dot deep in the coulomb blockade regime.
we study the creeping of a soft metal under constant stress.   accurate time records show that this creeping actually displays the following time dependent noisy component. in response to an external source of noise the two models ( the local one and the physical one ) predict fluctuations with a correlation time that increases before the catastrophe, just as is observed experimentally.
radio observations of many active galactic nuclei ( agns ) in the mhz through ghz frequency range reveal inverted radio spectra with spectral indices @xmath0 (@xmath1 ) and @x math2 ( @x Math3 ).   the inverted spectrum of ngc  3031 ( m  81 ) is consistent with optically thin synchrotron emission of a monoenergetic distribution of relativistic electrons in a radio jet, i.e. a spectrum of the shape @x maths2, as was recently suggested by reuter & lesch ( 1996 ). here  , we propose that the inverted radio spectrum arises from the synch rotary emission of expanding radio jet components ejected by a central engine of an active galactic nucleus at lower frequencies. to test this idea, we investigate the broadband spectra of blazar type agns in the cm to mm range and show that the observed inverted spectra are in agreement with the sum of the syn chrotron spectra for a few components of a single component of a relativistically jet ejected by the central engine. using inverse - combs and hydromagnetic turbulences, we find that the combined action of
the legendrian knot complement problem in the surgered manifold is solved by a generalization of the theorem by gordon and luecke ( 1989 ).   the main ingredient for this is the fact that if there is a non - trivial contact dehn surgery along a Legendrian knot in @xmath2 resulting in a legendrian unknot in its exterior, then this legendrian knots has to be a legendriansunknot of a very special type. here   i present a new formula to compute the thurston - bennequin invariant of such legendrian Unknots in the Surgered manifold using the monte carlo formula for the number of contacts between two links in an oriented closed @x Math0-manifold with a contactomorphism type of its exterior as the contactomorphic type.. moreover, in sections  -- and  i show how to do a crossing change in aLegendrian knot diagram with help of a contact dehhn surgery.
the discovery of anisotropies in the cosmic microwave background ( cmb ) has had a major impact on our understanding of the origin of the universe.   the results of the first detection of these fluctuations in the cmb by the _ cobe   dmr team in 1998 have led to a dramatic increase in the number of experiments that have been published or submitted for publication, and more than a dozen groups have reported detections covering the full range of frequencies and a wide range of angular scales. over the same period  , much progress has been made in data analysis techniques and in the theoretical interpretation of cmb data. however, since much of the progress is incremental, it is not always obvious just how far we have really advanced. in this paper   we take stock of the current state of the art in the field, and consider the impact of the cMBM anisotropy on the models of the early universe.
thermal convection is an important mode of heat transport in the interiors of stars and planets, as well as in many engineering applications.   rayleigh - bnard convection ( rbc ) is an idealized model of thermal convection, in which a fluid, placed between two horizontal thermally conducting plates, is heated from the bottom and cooled from the top. for large- and infinite prandtl numbers,   the flow structures and global quantities, e.g., the nusselt number and reynolds number, exhibit similar behaviour for three dimensions ( 3d ) and two dimensions ( 2d ). in the present paper, we analyze the flow behavior of 2d and 3d flows for large prandTL numbers, and show that the flow in the third direction in 3d rbc gets suppressed, and the large - scale fourier modes of 2D and 3 d rbc are very similar. to validate our results, we compute the spectra and fluxes of the kinetic energy and entropy for 2d or 3d flowing fluids, and demonstrate that the viscous and thermal dissipation rates for 2c and 3c rbc behave similarly. for completeness and validation
the gravitational and electromagnetic radiation from the tidal disruption of a main sequence star and a helium star by a massive black hole is studied using a three dimensional relativistic smoothed particle hydrodynamic ( sph ) code.   the effects of the tidal compression and disruption of the star and the black hole on the gravitational wave and photon emission are investigated. in particular, the characteristics of the gravitational waves and the photon flares observed during the disruption process are discussed.. the detection of the gamma - ray / uv emission caused by the tidal compressional heating and disruption can be used to determine the direction, occurrence time and possibly the redshift of the event, as well as to obtain independent evidence for the existence and properties of themassive black hole.    the detectability of the detected gravitational waves is also discussed.
abstractastrophysical shocks are collisionless shocks that form in tenuous cosmic plasmas via collective electromagnetic interactions between gas particles and magnetic fields.   they play key roles in governing the nature of cosmic plamas : 1 ) shocks convert a part of the kinetic energy of bulk flow motions into thermal energy, 2 ) shocks accelerate cosmic - ray ( cr ) electrons by diffusive shock acceleration ( dsa ), and amplify magnetic fields by streaming crs, 3 ) shocks generate magnetic fields via the biermann battery mechanism, and 4 ) curved shocks generate vorticity and ensuing turbulent flows. here   we review recent studies on the effects of shocks in the intergalactic medium ( igm ) and the turbulence in the interstellar medium ( ism ) on the structure of the universe.
positronium, an electron - positron bound state, is a particularly simple system which offers unique opportunities for testing our understanding of bound - states in the framework of quantum electrodynamics ( qed ).   because its constituents are much lighter than any other known charged particles, the spectrum and lifetimes of positronium states can be understood with very high precision within an effective theory of electrons and photons. here   we review some recent improvements in the theoretical description of the hyperfine splitting ( hfs ) between the ground state and its radial excitations in positronial states, and briefly touch upon implications for new physics searches.
the existence of a higgs boson with a mass of about 126 gev is the most important legacy of lhc run - i.   however, what is the actual number of scalar doublet fields present in nature?   although the standard model ( sm ) higgs state is constructed of only one isospin doublet field, it is well known that multi - doublet models can be considered by arranging additional parameters suitably, and they are often introduced new physics models beyond the sm. here  , we discuss how to extract information on the true dynamics of the extra ( pseudo)scalar bosons at the collider concerned from the sm predictions.
the vortex - interface interaction between the superfluid core and the crust - core interface of a neutron star is studied using the vortex cluster model for its core dynamics.   the intercations of the proton vortex lattice at the boundary of the superconducting neutron - proton liquid at supranuclear densities are shown to occur at the interface of the two phases of dense matter in the core, which are supported by a feynman - onsager Vortex lattice state that is associated with the onset of either a kaon - condensed phase or a deconfined quark plasma. as a function of the density of the nucleonic matter, the transition from the kaon- to the decoiled phase is accompanied by an increase in the critical velocity of the vortex nucleation in the nucleus - proion liquid, which is dependent on the surface roughness of the inner surface of the neutron star ; the latter is explained by the existence of a potential barrier acting on the vortex lattices at the edge of the delocalized proton vortices. under these conditions, the spin - up time - scales of the pulsar b0833 - 45 and b0531 + 21
quantum phase transitions ( qpts ) are physical processes arising from a change in the ground state structure of a system as a parameter crosses a transition - or - critical point.   it is known that the amount of entanglement present in a system is maximal at, or close to, the critical point of a second order qpt @xcite. recently, there has been interest in knowing how correlations, either classical or quantum, behave at finite temperature in models showing well understood Qpts @xcitedite. here   we investigate this issue using the grand canonical - ensemble theory and show that the number of particles can be exchanged in such a way that the scale behavior of characteristic variables in the vicinity of the critical points is more complex than previously thought.
many believe the next generation of resonant - mass gravitational wave antennas will be of spherical shape @xcite. to take full advantage of these capabilities, one needs to interpret the data such a detector will produce.   recently, much work has been done to understand the output of a spherical antenna equipped with resonant transducers ( rt ) equipped with ~1.5  j / cm2 amplitudes of gravitational waves. in this article, we show that the solution to the inverse problem for a noiseless spherical antenna can be solved analytically using a symmetric metric theory of gravity and that this technique can be extended to a noisy antenna with independent and equally sensitive detector outputs.
microsquids or nanosquids with ultra - low flux noise are being developed for the investigation of magnetization reversal of magnetic nanoparticles ( mnps ) in superconducting quantum interference devices ( squids ).   the most successful approach is the squid - on - tip ( sot ) technology, which is extremely powerful for high - resolution scanning squid microscopy, and provides for the first time a spin sensitivity below @xmath10 for certain intervals of applied magnetic field up to about 1 tesla ( @x Math11 is the bohr magneton ). here  , we report the optimization of the design of yba@xmath0cu@x maths1o@x math2 ( ybco ) direct current ( dc ) nanosqids with grain boundary josephson junctions ( gbjjs ) inserted into the squid loop @xcite using the calculation of the coupling factor @xMath13, i.e.  the amount of magnetic flux coupled to the squid per magnetic moment of a point - like mnp, placed on top of a narrow constriction inserted into an additional constriction. by using numerical simulations, we show that the squid induct
collinder 419 is an open cluster in the constellation cygnus that contains the bright star @xmath3  normae = hd  149038 and a host of surrounding fainter stars.   we present a new assessment of the distance to the cluster based on spectroscopic and optical long baseline interferometry of the central multiple star, hc  193322 = hr  7767 = hip  100069 = wds  20181 + 4044, and photometry of five of the brighter members using the kitt peak national observatory ( kpno ) 2.1  m telescope and cassegrain focus, goldcam ccd spectrograph. for each of the four blue stars,   the observed wavelength range was 4050  4950 , a region that includes numerous h balmer, lines in o- and b - type spectra, and a region of intense red shifts in the spectral energy distributions of the two spectroscopically close companions stf 2666 ac and tar 5 ad. by combining these observations with data from the ucac3 and 2mass catalogs, we show that the cluster is composed of a large number of fain
the discrete - time quantum walk ( qw ) is a quantum counterpart of the classical random walk.   the behavior of the qw is quite different from that of the random walk and is expected to be connected with various phenomena in quantum mechanics. in the present paper, we investigate the limit distribution of the Qw from a viewpoint of the differential equation. taking an account of the singularity in the limit distributions, we treat a class of fucksian linear differential equations of the second order. for discrete- and continuous - time qws, we are led to a heun s differential equation ( he ) and a hypergeometric differential equation by gauss ( the gauss equation, ge ). through these results,   authors believe that the he and the ge play an important role in understanding the qws.
we present a path integral molecular dynamics study of 3c - sic at temperatures between 100 and 1200 k and pressures up to 60 gpa.   the electronic structure was treated with a non - orthogonal tight - binding ( tb ) hamiltonian as a reasonable compromise to reduce the computational cost of deriving the born - oppenheimer ( bo ) energy surface for the nuclear dynamics. in the simulation,   both the electrons and the atomic nuclei are treated quantum mechanically in the framework of the bo approximation, so that phonon - phonon and electron - phonons interactions are automatically considered in the simulations.the results for the thermal expansion coefficient and the temperature dependence of the direct electronic gap in 3c-sic are presented and discussed in sec.iii, dealing with the thermodynamic properties of the electronic gap.
the dynamics of two coupled particles evolving in a spatially periodic and symmetric potential landscape are studied.   the system is driven by a chaotic attractor, while the other particle evolves on a periodic attractor. as the coupling strength of the two increases, the number of attractors for each particle increases and the current reversal or current suppression becomes more difficult to predict. using three - dimensional projections of the phase - space, we show that the emergence of a vanishingly small current coincides with the transition of the second largest lyapunov exponent to zero and subsequently becoming positive. this coalescence of the attractors means that transporting channels become suppressed with the particle dynamics being captured on a single chaos attractor preventing the occurrence of a current at all.
in the nlc linear collider, the energy spectrum of the disrupted beam in the beam extraction line which transports the beam from the inter - detector ( ip ) to the beam dump is used to determine the luminosity of the experiment.   this is done by measuring the beam profile measurement at the secondary focus and reconstructing the beam energy spectrum based on the measured beam profile. here   we present a new design of the nLC extraction line optics with a vertical chicane generating a 2  cm displacement and dispersion at the second focus. using guinea   pig code, we show that the particle tracking and measurement simulations for the extraction line with the horizontal chicane are better than those with the vertical one.
the metropolis  hastings ( mh ) algorithm provides an iterative and converging scheme to sample from a complex target density @xmath0.   each iteration of the algorithm generates a new value of the markov chain that relies on the result of the previous iteration. due to its markovian nature,   this algorithm is not straightforward to parallelize, which creates difficulties in slower languages like r @xcite. nevertheless, the increasing number of parallel cores that are available at a very low cost drives more and more interest in " parallel - friendly " algorithms, that is, in algorithms that can benefit from the available parallel processing units on standard computers. here   we present a new scheme for improving the parallelism of the monte carlo estimation of the likelihood function in the independent metropolises ( imh ) method, called " block independent metropolis / hastings" ( block imh).this improvement depends on a choice of permutations on @x Math2 that is described in details in section . as a consequence  , we can take advantage of the parallel abilities of arbitrary items of computing machinery, from cloud computing to graphical cards ( gpu )
the hardy - littlewood maximal operator maps functions of bounded mean oscillation back to bmo.   this is a classical result of bennett, devore, and sharpley in the regularity theory of parabolic partial differential equations. here  , we show that the same operator of forward - in - time maximal averages that generates the parabolic weight theory also maps the class of positive functions in parabolic @xmath0 into itself. by taking into account the time - dependent nature of the functions under study,   the results are consistent with the " elliptic " result in @xcite when only positive functions are involved. on the other hand, if the functions are sign - changing, a full analogue of the bennett - devore - sharpleY - bennett method is needed.. the new method is shown to be more general than the classical one.
abstractthe rotational period of the helium atom hd  184927 has been estimated by combining stokes v spectra from the cfht spectopolarimeter and magnetic field measurements from the sao zeeman analyzer and uwo photoelectric polarimeter.   the results are consistent with previously published data from wade et al. in a recent article , we show that the rotational periods of hd184927 are very similar to those of previous studies . here   we present a new method to estimate the rotation period of hD  18 4927 using the lsd procedure.    we find that the observed rotational velocity is about 0.5 km / s, which is within the range of projected rotational velocities for the region of interest ( r2=0.7 - 0.9 km / sec ) measured by @xmath2 and he 4922 line at the dao 1.8-meter plaskett telescope during the same period. on the other hand, the calculated rotational time scale is about 10 years longer than previously reported . this difference is explained by the fact that the angular rate of the
compressive sampling, also known as compressed sensing, is a technique for acquiring and reconstructing signals in the sparse - land.   the purpose of this paper is to propose to use compressive sampling for remote control systems. in this paper, we propose a new feed - forward - based remote control system with compact compression of the control signals with sparse representation using the _ compressive sampler   technique. by solving the @xmath1 optimization problem, we can efficiently obtain sparse representation of the signal under a certain signal representation ( e.g., fourier or wavelet ) without much information distortion, such as aliasing.
one of the classical problems in galaxy dynamics is building equilibrium models for a galaxy with an observed light distribution.   the schwarzschild method has been extensively applied to study nearby elliptical and s0 galaxies under the assumption of a static spherical, axisymmetric or triaxial potential ( e.g., richstone & tremaine 1988, merritt & fridman 1996, rix et al. 1998 ), and has also been applied to build 2-dimensional models of external bars ( pfenniger 1984, wozniak 1997, sellwood & wilkinson 1993 ) and 3-dimensional model of the tumbling bar of our own galaxy ( zhao 1996 ). here   we review the current state of the art in the field, and discuss some of the limitations of the method.
we derive and investigate the analytical expression for the probability density function of overdamped particles in a piecewise linear random potential driven by a constant force at zero temperature.   the results are obtained for a special class of systems containing quenched _ dichotomous  disordered and subjected to a constant bias force. as a result  , we obtain the exact statistical characteristics of the solution of the langevin equation for the overdamped dynamics of a classical particle in a one - dimensional random potential with a constant biased force. here   we also compare the analytical results with those obtained from direct numerical simulation and derive the asymptotic behavior of the probability densities in the limits of small and large times.
pulsed laser depostion ( pld ) is an increasingly used growth method which is particularly suited for the fabrication of multilayer thin films.   the aim of the present work is to improve our understanding of pld by investigating the growth morphology for different growth parameters in a simple model. using kinetic monte carlo simulations on a lattice of @xmath8 sites, we investigate the scaling behavior of the time - dependent nucleation density in pld and the influence of ehrlich - schwoebel barriers on the morphology of surfaces grown by pld.    we find that the rate at which particles hop down the edge of an island is reduced when ehrs barriers are present, and that the islands grow in a fractal manner before they coalesce. while the size of the islands increases with the increasing intensity of the pulses, the number of atoms deposited per unit area decreases with increasing the diffusion constant. as the density of incoming particles increases, the average flux density decreases, and the shape of the surface becomes smoother.
the primordial density perturbation of the universe is the earliest relic we have of the big bang, although it is not clear exactly when it was generated.   long before any relevant observations were available, it was argued from general considerations of the formation of large - scale structure ( lss ) through gravitational instability that the density perturbed universe should have a scale - invariant ` harrison - zeldovich'( h - z ) form : @xmath1 { \rm e}^{-i\vec{k}\cdot{\vec{x}}{\rm d}^3x$ ]. in this article   we review the history of the use of precision measurements of the cosmic microwave background ( cmb ) anisotropy to determine cosmological parameters with unprecedented accuracy and discuss the recent advances in the field.
the bocce ( bologna open clusters chemical evolution ) project aims to precisely and homogeneously derive the fundamental properties of a large, significant sample of open clusters ( ocs ).   we have already analysed photometric data for 35 ocs, by comparing observed and synthetic colour - magnitude diagrams ( cmds ) and producing age, distance, reddening, and approximate metallicity on a homogenous scale. in this paper  , we compare these results with those of @xcite, which has obtained spectra for a dozen ocs and used tgmet to derive atmospheric parameters and absolute magnitude of the stars. using three stars in common, we find differences of the order of 0.1 dex for the light, @xmath6, and iron - peak elements ; very large discrepancies are found instead for the three neutron - capture elements   zr, ba, and eu ; conversely, there is a very good agreement for the lanthanum abundances.
the lhcb experiment is the only dedicated heavy flavour experiment approved to run at the large hadron collider ( lhc ) at cern.   it is designed to operate at a luminosity of @xmath11, which maximises the number of bunch crossings with exactly one interaction and reduces the radiation damage to the vertex detector. in the first year of operation,   a data sample of@xmath10 meson decays will be collected at the design luminosity, and the aim of this report is to improve the precision of these measurements by running the experiment at higher luminosities for five years. during this time   we will explore the physics reach of a 100  data sample for selected key measurements : the mixing phase from the tree decay, the penguin decay and the ckm angle as well as the mass difference between the eigenstates of the tree and the penguin decay.
effective samplings in the conformational space by monte carlo and molecular dynamics simulations are necessary to predict the native structures of proteins.   the replica - exchange method ( rem ) @xcite is one of the most well - known generalized - ensemble algorithms, but it is difficult to use in complex systems such as proteins because the canonical - ensemble simulations tend to get trapped in a few of many local - minimum states. in this article  , we propose a new type of hamiltonian rem where we exchange the scaling factor of the van der waals radius of solute atoms in the interaction terms among solute atom only. by reducing this scaling factor,   steric hindrance among solutes will be reduced and wide conformational spaces can be explored. using this method, we applied this method to the sytems of an alanine dipeptide with explicit water molecules and tested the effectiveness of the method by comparing the results with those from the conventional canonical method.
the loop expansion is a simple and well - developed expansion scheme in powers of @xmath3 that is derived from the path integral @xcite.   the mean meson fields are included non - perturbatively, and the correlations are included perturbedatively. therefore, one can analyze the many - body effects order by order. here   we show that the loop expansion up to the two - loop level allows us to describe nuclear matter ( and presumably nuclei ) with greater accuracy than the previous work using the density functional theory.. the results are consistent with experimental data, and it is shown that the long - range dynamics are included explicitly, and short - range physics is contained in the parametrization.
correlations between spatially separated cosmic ray events would indicate that the particles have some common history.   we have studied data obtained with the california high school cosmic ray observatory ( chicos ) array during january 2003 through june 2005 and searched for evidence of correlated air shower events separated by @xmath6  km with an energy threshold @x Math7 ev. in this work  , we search for double trigger events where two sites, separated by more than 1  km, both record trigger events within a certain coincidence time. using a randomized data set constructed directly from the real data, we find no evidence of time correlations in the event sequences of two sites separated by about 2  km.    such a signal could indicate the existence of isolated correlated cosmic rays separated in distance by up to 60  km ( the largest distance between two chicos sites ).
abstractthe present solar activity cycle is among the weaker ones, particularly if compared with the sequence of strong cycles during the second half of the 20th century.   the present cycle was preceded by an unusually extended period of very low activity, weak polar magnetic field, and low heliospheric open flux, which is consistent with the empirical correlation of the polar field around solar activity minimum with the strength of the subsequent cycle. in this study, we have used surface flux transport simulations to investigate the influence of the individual tilt angles and magnetic polarities of bipolar sunspot groups on the evolution of the solar polar field during the declining phase and activity minimum of cycle 23. using these data, we show that the polar fields at the solar surface are reversed and built up by preferred flux transport of one polarity across the equator as a result of the systematic tilt of bipolar regions with respect to the direction of rotation. for the first time, we also show that even single big bipolar regions emerging very near or across the solar equator can significantly affect the amplitude of the resulting polar field.
@xmath0 interactions produce particles having final states with @xmath3 of + 1, where @x Math3 is the charge conjugation number.   this luminosity can be measured at the nlc as a proof - of - principle for a low energy @x math0 testbed, where it would be possible to singly produce the higgs boson ( whereas it must be produced in pairs at e@xmatrix4e@xmetrix5 colliders ). in this study   we demonstrate that with suitable choice of laser and optics parameters the resulting @xMath0 luminosity could be made to exceed the virtual @x maths0 luminosities from e@Xm06@xmtl5 collider.. this luminoseconds can thus serve as the basis for a physics program at the testbed facility, e.g., heavy quarkonia studies.
we investigate the effects of low - dimensional many - electron plasmas confined in a quasi-1d ion trap on the behaviour of quantum correlations among the trapped ions.   we find that the number of electrons in the trapped system increases linearly with the density of the ionised atoms and, at sufficiently high coupling, condense into a regular lattice, fulfilling early predictions generally attributed to wigner. upon changing the temperature and/or the strength of the applied electromagnetic field,   the order - disorder transitions observed in experiments are replaced by isomerisation transitions, which are characterised by a linear to zig - zag phase change. as a result, the vibrational spectrum of the system changes from a single unit cell to a series of quenched molecules, which can be tuned by varying the relative weight of the first and second nearest neighbour interactions. for systems with a magnetic ( spin ) moment of 0.5  kcal / mol, this transition is continuous and second order, with a discontinuity in the second derivative of the ground state energy with respect to the 1d ion density. however, when the spin of the trapped ion is half integer, the transition is more complex, with the
a general method for calculating electronic transport properties is provided by the use of non - equilibrium green s functions ( negf ). in this paper   we examine the way in which the leads permitting transport through an open quantum system ( a " device " ) can be replaced by self - energy terms in a dyson s equation.   the analysis is limited to the case where the leads can be well - approximated as systems of spinless, non - interacting electrons in local thermodynamic equilibrium. in principle   this approximation is not very restrictive, since sufficiently far even from a mesoscopic device the wires carrying current become macroscopic and the device whose transport properties are being calculated is left completely unspecified. however, we show that the feuchtwang approach for the continuum also can be repackaged so that leads are replaced exactly by simple self - energies, and to explore this possibility in some detail.
we investigate the properties of the path integral over reparametrizations in quantum field theory by applying analytical and numerical methods to its discretized version (  ).   we reformulate the problem in the language of a proper ( subordinator ) stochastic process and find that typical trajectories are in general not brownian but rather may have discontinuities of the type of lvy s flights, e.g.  lyve s flights. for the gamma - subordinator form of the measure, we show that sample trajectories have a fractal structure with the hausdorff dimension ranging from zero to one, which varies between zero and one depending on the form of their integrand. for both the logarithmic and gamma- and off - shell qcd scattering amplitudes  , we find that these trajectories do not have the same fractal shape as those for the standard random walks.
the quantum phase transitions in two - dimensional ( 2d ) superconducting arrays with general capacitance matrices and discrete charge states are investigated using the monte carlo method.   the results show that the system at zero temperature exhibits a transition between the mott insulating phase and the superfluid phase, displaying lobes - like structures in the resulting phase diagram. here   rational charge frustration introduces commensurability effects to the array, leading to the solid phases with various charge densities. as the ratio of the junction to self - capacitances increases, more and more insulating lobes are observed in the phase diagram, suggesting the existence of a lobe at every rational frustration in the thermodynamic limit. to check the robustness of the lobes against finite temperatures, we apply the monterme carlo technique to the system without the josephson term and find the persistence of the insulating Lobes with low - order rational values of the charge density. for the self - charging limit, the possibility of a reentrant transition is also pointed out.
the origin of hysteresis jumps in the main branches of high t@xmath0 superconductors is investigated.   it is shown that the origin of the multi - branch structure is the nonlinear effect among phase - differences through the charging effect. to explain the main branch structure,   the following mechanisms are proposed : ( 1 ) a charging at a superconducting layer induces the change of electric fields in the neighboring insulating layers and induces an inter - layer coupling, since the time - derivative of the phase - difference is related with the voltage ; ( 2 ) the dissipation in the superconductor layer enhances the occurrence of jumps in both increasing and decreasing current ; ( 3 ) the charge relaxation in the Superconducting Layer dampens the motion of phase - changes in each junction ; ( 4 ) the surface proximity effect affects the way of formation of hy Stevesis jumps ; ( 5 ) the d - wave effect is also discussed. by comparing the result of numerical simulation with the experiment of a small stack @xcite, we show validity of the present model.
the hypothesis that novae hibernate in the millenia between outbursts predicts that very old novae should be much less luminous than those seen in the 20th century, because mass transfer in these systems has diminished or stopped entirely.   we took three @xmath1-band images and one h@xmath2 image of the field of v529 ori, or nova ori 1667, on august 15 and 16, 1993, with the 1.0-m jacobus kapteyn telescope at la palma. using the numbers in the newswire item reported by r. t. fienberg ( 1995 ) to be the hibernating nova, we show that there are two components : star 5, using the number in the story that was published by this author, is actually star 5 from 1950.0 positions, to within 0.4  absolute and 0.1  relative of component a, and star 2 is star 2 from 05.638 positions, which are consistent with the results of spectroscopic analysis of the spectra of the two components.
the chemically peculiar star hd103498 ( 65umad, hr4561 ) is a member of a multiple - system which consists of four objects.   it is a south - eastern component of the visual binary ads8347 ( separation 63@xmath0 ) containing hr45 61 and hr4560 with the latter being a spectroscopic binary 65umaac. on the basis of the peculiar indices and ap spectral classification, this star was observed using high - speed photometric technique as a part of survey programme for searching photometric variability in the chemically peculiar stars. to search the photometric light variations in the short period ( @xmath13 min ) pulsating variables, we obtained time - series photometric data through a johnson's filter with an integrations of 10-sec each for a total duration of 36-h.the results of the photometry show that the radial velocity ( rv ) amplitude of the pulsating star varies from ~1.6 to ~2.5  km / s with a period of ~3.4  h. the rv amplitudes of these variations are significantly larger than the photometrical amplitudes and the pulsational signal may be detected
the transmission profile of a chromium film, in the restricted wavelength domain, is studied.   the transmission pattern is found to be similar to that obtained with a metallic film. as a consequence of this observation,   it is suggested that the role of surface plasmons ( sps ) in the transmission could be replaced by other kinds of eigenmodes and the observed transmission spectrum features can be better depicted as a series of fano profiles.
there are a growing number of alma observations in the millimetre regime to support the existence of discs around ob - type protostars.   these agree with a scaled - up paradigm of low - mass star formation beyond @xmath110 - 15m@xmath3. however, high - resolution and high - sensitivity observations at such wavelengths have been lacking as previous interferometric arrays could not achieve either ; or have only achieved enough resolution for the most nearby sources ( e.g. @xcite ). here   we detail our alma data zooming into w33a ( g12.91 - 0.26 ), a relatively nearby archetypal massive star formation site ( 2.4kpc, @xaite ) where we focus on one of two previously detected strong continuum emission regions, mm1@xcite in an effort to search for a keplerian disc around the dominating high - mass protostar designated mm1-main ( l@x Math13.2@x math810@xMath9l@x maths3 ). using a modified version of the nir adaptive optics integral field spectroscopy ( sma ) model of star formation, we
the mid - infrared ( mir ) spectra of the nearer dwarf galaxies iizw40, ngc1140 and ngc1569, with metallicities of to z@xmath6, along with the spectrum of the notoriously metal poor sbs0335 - 052, are presented.   all these spectra show obvious mir signatures of massive stars, as often seen in starburst galaxies, and are dominated by steeply rising continua longward of @xmath0 10 @x Math5 m. thermal emission from hot small grains with mean temperatures of the order of hundreds of kelvin are responsible for the mir continuum emission. while the unidentified infrared bands ( uibs ) at 6.2, 7.7, 8.6, 11.3 and 12.6 @x math5 m are attributed to aromatic hydrocarbon particles undergoing stochastic temperature fluctuations, they are also observed to peak in the photodissociation zones around hii regions, but are destroyed deep within the hii region themselves. here  , i concentrate primarily on results of the near dwarf galaxies, since impacts of the massive clusters on the global dust and gas environment are very pronounced in these relatively small objects.
we draw a descriptive relationship between vision, cognition, and information visualization.   we assume that well - designed visualizations must stimulate visual and cognitive processes in a way that reasoning is amplified. to this end, we review the steps that take place during vision - cognition phenomena when the goal is data analysis. in survey fashion, we compile the literature introducing the following contributions :   theoretical compendium : we draw a description of vision and cognition in the realm of information visualization ; discussions : we debate our rationalizations over extensive literature ; reflections : we provide study cases to revisit design practices ; and reflection : we discuss the role of design principles in the promotion of visualizations.
photoionization models for chemically homogeneous gaseous nebulae of constant density predict an almost constant temperature ; consequently, observers often assume a constant temperature to determine chemical abundances.   the spatial temperature inhomogeneities in  regions are usually characterized by @xmath1 the mean square temperature variation in three dimensions. from previous work it has been found that @x Math1  is in the 0.002 to 0.025 range, for objects with solar or subsolar chemical abundences, with typical values around 0.005. to study this problem further we decided to obtain an independent measurement of @x math1  based on over a million temperatures determined across the face of the orion nebula using the hubble space telescope ( hst ) and its narrow - band interference filters. since the columnar temperatures already represent an average temperature it is not possible to obtain directly from them the full @x maths1  value but instead it is possible to estimate @xMath1  from the mean squares of the temperature variation measured in the plane of the sky. here   we present the method for deriving the temperature obtained from the hst image and the analysis of the data as well as the
the origin of the masses of fermions and gauge bosons in the standard model ( sm ) remains a mystery.   the coleman - weinberg theory, which is based on the renormalizable, chiral gauge theory, has been used to test the predictions of the sm for small values of the higgs mass, close to the current experimental bound, @xmath6  gev  . however, the hierarchy of the fermion masses of the different generations remains unexplained. using warped extra dimensions, we show that the origin of these masses can be explained by the decay of the electroweak symmetry at the boundaries of the broken gauge symmetry, and by the propagation of the scalar fields in the warped extra dimension.
observations at submillimetre wavelengths have always been severely hindered by the atmosphere, which is only partially transparent throughout the region.   the main limit to sensitivity, particularly at the shorter submillimeterre wavelengths, arises from sky - noise. in this paper   we concentrate our discussion on how to remove the error due to sky variability from array data taken with the sub millimetre common - user bolometer array ( scuba )@xcite at the james clerk maxwell telescope ( jcmt ).
we present a systematic analysis of the fourth order gravity ( fog ) model for the galactic distribution of dark matter ( dm ), in the framework of general relativity ( gr ).   the main topics of the analysis are the theory of the field equations and their newtonian approximation, the solution for the gravitational potential and the mathematical models for the Galactic componets. as astrophysical application  , the modified potential has been used to build the rotation curves for the milky way and ngc 3198 using the navarro - frenk - white model ( nfw model ) @xcite. in this paper   any galactic component ( bulge, disk and dm component ) required an onerous numerical computation since the gauss theorem is not applicable in the fog.the data fit between our theoretical curves and the data of the rotation curve of the milvey way and the galaxy ngc3190 is presented.
the existence of neutrinos has been the subject of much debate in recent years.   the first observation of a massive tau neutrino has been reported by the donut collaboration and the results from the superkamiokande collaboration are now being reported. here   we review the current state of the art in the field and discuss the implications of these findings.
the prediction of the mass of the lightest mssm higgs boson @xmath4 is one of the most striking features of the minimal supersymmetric standard model.   it is known that the yukawa - enhanced contributions of the top and bottom quark couplings are the most important one - loop corrections, but the two - loop counterterms are not well understood. in this paper   we close this gap by a detailed evaluation of the counterterm structure of the monte carlo counterterms at two-loop order.. the results show that the asymmetry - restoring counterterms of the higgs, quark and squark sectors are symmetric and generated by multiplicative renormalization. however, the supersymmetry identities for the three - point and four - point functions are broken by a finite amount, which could be relevant for precision calculations of @x Math4. to address this issue, we have used the regularization by dimensional reduction ( dred ) scheme to evaluate the effects of the electroweak gauge couplings on the symmetry - restored counterterms from the non - supersymmetrical counterterms. using the lhc and ilc schemes, we find that the supers
we study the low  energy physics of heavy fermion materials using continuous time quantum monte carlo method ( ct  qmc ) for the solution of the kondo lattice hamiltonian problem@xcite.   we find a convergence of the conduction electron self  energy extracted from the solution with respect to the periodic anderson model ( pam ) to the one obtained within the konda lattice model ( klm ) by using an inverse relationship to extract the f  electron self energies and monitor how the low frequency behavior of the aim converges to the limit of infinite dimensions @xmath1, where the local spin is compensated as the temperature falls below a characteristic kondo temperature.
the structure of the external magnetic field of a spherically and slowly rotating magnetized star in a randall - sundrum ii type braneworld has been considered in approximation of small distance from the surface of the star.   the model is based on the schwarz - nordstrm solution of the geodesic equation of massive test particles in higher dimensional spacetimes which is obtained by solving maxwell s equations for the external electromagnetic field of the slowly rotating star in the branworlds using the general relativistic theory of gravity, i.e. general relativity. as a result of the calculations,   two different types of external magnetic fields have been found to exist around the black hole, namely, an external asymptotically uniform magnetic field with a diameter of about 1.5 cm and an internal one with a radius of about 0.1 cm. under these conditions, the outermost stable orbits of the test particles are observed to be in the innermost part of the magnetic field around the central black hole while the inner most stable orbits are in the center of the spacetime around the main body of the black holes. this observation is attributed to the presence of strong magnetic
the kagom and pyrochlore lattices have attracted special attention both experimentally and theoretically because of their unusual low temperature behaviors.   the first - neighbor classical heisenberg model on such lattices has a t=0 entropy, but the effect of quantum fluctuations on these different structures remains to be fully understood. in the large s, first - order spin - wave approximation, all these magnets remain disordered ; however, higher order approximations have been devised that lead to selection of order out of disorder by quantum fluctuations. here   we show that this is not the case for the 2-dimensional analog of the two - dimensional analogue of the kagamorite@xcite. from the spectrum of low lying excitations obtained from exact diagonalizations up to @xmath0, we conclude that the system has no nel spin long range order ( lro ) in the form of a spin-1/2 magnet.
we compare two different methods to simulate the steady state of a system of hard spheres interacting through a square well potential.   the first method is brownian cluster dynamics ( bcd ) and the second is event driven brownian dynamics ( edbd ). with bcd clusters are constructed by forming bonds between spheres within each others interaction range with a given probability. with edbd hydrodynamic interaction is ignored and the bonds are inherently completely flexible. in this paper   we show that for reversibly aggregating systems bond rigidity has no influence on the structure of the equilibrium state, but has a huge effect on the dynamics. using both methods we find that the self diffusion coefficient as a function of the interaction strength is almost the same at steady state with both methods. however, when the bond flexibility is taken into account the results are very different because the interactions between the clusters are more or less flexible.. the influence of bond flexibility and intra - cluster hydrodynamical interaction is discussed.
we present a new analysis of the cosmic microwave background ( cmb ) temperature map in the frequency band 70 ghz.   we look for ring - type structures in the real cmb temperature map as measured by the planck collaboration as well as the foreground removed maps smica, sevem and nilc. to avoid the foreground  , we took only those points whose disc of radius does not overlap because the width of the ring is @xmath8 and the largest radius we used was@xmath9 with the foreground map in more than @x Math10 of the area.. we also took various foreground - removed maps provided by thePlanck team to compare.    we find that the results are consistent with the predictions of conformal cyclic cosmology ( ccc ) of roger penrose ( penrose 2010, gurzadyan @x math6 penrose 2013 ). while their work was concentrated on low - variance circles, our analysis shows that certain cumulative distribution functions of the real maps are distinguished from that of the simulated maps generated by the healpix code ( grski et al. 2005 ).
information retrieval ( ir ) systems have become integral to daily activities of millions and will retain their prominence in years to come.   one of the reasons for such importance of a good ir system is the amount of data that is available on the web and the pace at which it is increasing. when a search query is given to an ir system, it retrieves links of pages that are prepared without taking query into consideration _ on the host side. due to this shortcoming, both the content provider and ir system   are under performing. in this paper  , we try to address this issue by proposing an architecture that enables the server hosting the website to present content that is based on the query posed by the user.
earthquakes have been associated with anomalous long - range interactions over long times and large spatial separations.   these results defy usual mechanical models of linear elasticity and one proposed explanation is that seismic cycles represent the approach to and retreat from a critical state of a fault network. here, we investigate the hypothesis, and its implications for the above observations, that the crust is a nonlinear elastic medium characterized by an asymmetric response to compressive versus extensive perturbations around the lithostatic stress. in particular, we show that the surface of the earth s crust at seismogenic depth is crisscrossed by joints, cracks or faults at many different scales filled with drained fluid in contact with delocalized reservoirs at pressures close to the lithotracker pressure. as a result,   the crust exhibits a threshold nonlinearity that is not explained by the elastic stress transfer model of stress redistribution and/or elastodynamic propagation of ruptures using laboratory - based friction law. instead, we argue that the earthquake - induced stress changes are due to the interaction between the crust and the microcracking of the fault system, which is mediated by a time - dependent process that relates fluid pressure, flow pathways and fluid
the ability of quantum mechanical systems in conducting, and their transport properties in general, have been greatly considered in recent years in connection with anomalous transport and localization phenomena @xcite.   one - dimensional non - periodic substitution potentials generated as substitution sequences have emerged as a convenient theoretical laboratory since they are neither completely random nor periodic, even though they are formed from well defined rules. here   we investigate here the tight - binding approximation to the problem of mesoscopic rings threaded by a time - independent magnetic flux, and calculate the persistent current and drude weight in cases where the on - site potential is given by some substitution sequences with different degrees of randomness.
we present a formalism for the polarization radiative transfer of electrons and proton polarization fractions from the kerr black hole ( bh ) to the ground state in a grmhd model.   we use adiabatic 3d simulations of thick accretion flow onto the bh with spins of different degrees of freedom to show that the polarization transfer can be used to study the effects of faraday rotation of the basis vector along the null geodesic on the polarization of the electron - proton magnetic field at large distances from the Bh.
we present photometry for ngc  6994, an object which appears in the lyng ( 1987 ) open clusters catalogue and that it is classified as open cluster also by simbad.   the aim is to provide some photometric data for this cluster, complementing the very poor informations we have, which basically consists of the cluster identification and diameter, which according to lyng  is about @xmath5 arcmin. from the acquired data, it turns out that ngc - 6994 is not a cluster, but just a random enhancement of bright stars.
electronic excitations generated during the adsorption of hydrogen atoms on metal surfaces have been studied using a range of techniques including electronic friction based methods, the time - dependent, mean - field newns - anderson model and density functional theory ( tddft ).   these methods use a nearly - adiabatic approximation in which the perturbation of the electronic system is assumed to be weak and slow. here   we present a new method for calculating the electronic excitation of electrons and holes over a schottky barrier at the surface of a metal - semiconductor interface using the time- and band - dependent newns / andersonian model @xcite. by coupling the energy distribution of excited electron - hole pairs with the spin - transition of the adsorbate orbital, we obtain a description of the rate - limiting step in the electronic transfer of energy from the ground state to the surface as a function of the distance from the surface where the excited pair of electrons is located.the experimental results of the chemicurrent experiments performed by nienhaus and coworkers [ white, wodtke and co - workers, j. d. white, s. w. white and p. w
we present data from continuous monitoring of the supernova sn 1987a with the rosat satellite ( rosat ) since 1991.   the pulsar photospheric probe ( pspc ) has been used to measure the soft x - ray component of the emission from the explosion of the compact object. in order to obtain a light curve of sn1987a, separate images were produced for all time intervals : source counts were extracted from a ring around the supernovae with radius 24 " for the high - energy radioimmunoassay ( hri ) and 40" for the pulse height spectroscopy ( pSPc ), respectively, containing roughly 90% of the source photons and about 95% of background photons. at the beginning and the end of the pspC lifetime, two different response matrices have been fitted to the data, assuming a fixed line - of - sight absorption column density of @xmath12 and a single - temperature raymond - smith thermal plasma model ( rs ), which is dominated by few emission lines, even if the abundance may indicate a more complicated ionization or temperature distribution. during the early part of the observation period, the russian mir - ttm and
@xcite is a new method for the calculation of the exciton binding energy, polarizability and wave function of the singlet exciton in the single - particle band structure of poly - diacetylene ( pda ) chains dispersed with low concentration in their monomer single - crystal matrix.   the model is based on a many - particle model hamiltonian that describes only the @xmath13-electrons and their mutual interaction with the lattice potential. using the density - matrix renormalization - group ( dmrg ) method, the ground state and elementary excitations for such models can be calculated for large chains with very high accuracy. within this model, the electron - electron interaction is treated without resorting to any approximations.the results of the calculations are compared with experimental data obtained by means of the perdew - burke - ernzerhof global hybrid density functional and the 6 - 311g(2@xmath8,2@X1 ) basis set of atom - centered gaussian functions, which give the following values : @xxmath6, @x math6 + 0.5, ~0.9, ~1.3, ~2
we study the nucleation of cracks in a brittle two - dimensional material, i.e.  a sheet with a thickness of one atomic layer, through langevin dynamics.   the rate constant for crack nucleation follows an arrhenius law, from which the energy barrier is extracted. in the present work, we use a stretched one dimensional chain model to study fracture in 2d brittle solids by bonding the chains to each other such that they form a square lattice. by constraining the dynamics of atoms along the applied strain   it is shown that the system can not form topological defects and the only mechanism for stress relaxation is fracture. also, by choosing the constraint along the application strain, we expect to be sampling the meaningful pathway for fracture while speeding up the simulation time.
the parametric resonance, or preheating phase, is a fundamental effect that must take place before the actual reheating of the universe through the thermalization of the produced particles @xcite.   recent studies on this reheating phase have shown the possibility of emergence of new and interesting phenomena, like explosive particle production, nonequilibrium symmetry restoration, among others effects @xcite. in this paper  , we show that the existence of instability bands in the parameter space of the fluctuation fields coupled to the inflaton field, where the floquet exponent may be either real or complex, results in the formation of exponential solutions of the equations for the modes @xmath0 of the fluctuations of the coupled fields. as a consequence,   the oscillating inflaton can be considered as a periodic mass for the other scalar fields that are coupled to it. by means of the polynomial expansion of the exponents of the Floquet exponent at the borders of the instability bands   one can define the so called stability bands, which are characterized by the exponential growth of the solution energies of the systems of modes associated to them. here   we study the fractality of the borders between two such bands
the breakdown of rotational covariance for the one - body component of the @xmath6 current in a light - front model, in a relativistic model with a null - plane wave - function @xcite, is discussed.   the results of the different prescriptions for obtaining electromagnetic form - factors from the covariant feynman one - loop triangle - diagram for the + components of the current, in two ways, one corresponds to the covariants calculation and the other to the non - covariant calculations. in the first way, the matrix elements of @x Math6 are obtained from the one-loop triangle diagram, which is integrated analytically in the -component of the loop momentum ( @x math8 ) in the breit - frame with momentum transfer@xmath9, and numerically in @xmatrix10 and @xmetrix11. the cauchy integration in the second way is not exact in the present case of spin 1 composite particle, since the resulting matrix elements do not satisfy the angular condition and the form - factor now depends on the prescription used.
wireless sensor networks ( wsns ) are based on tiny sensor nodes which have limited energy.   the main constraint in wsn is the lifetime due to limited energy of the sensors. here  , we propose a new protocol for efficient data gathering with mobility - based routing protocol ( srp ) using mobile sensor network ( ms ) in w Sn environments.. firstly, we introduce ms in the field and then we enhance the data collection by ms in clusteless network., secondly, we extend conventional routing protocol stable election protocol ( sep ) @xcite removing its clustering mechanism and introducing ms in our proposed scheme srp. when sink is moving on the predefined trajectory the sensor nodes in the fields and gathering data, only sensors in the sensing range send their data to the sink while other nodes which are out from sensing range go in sleep mode until sink arrives. as the sink is sometimes out of the range of many sensors and data sending takes much energy, we are introducing ms into our proposed protocol srp to find the shortest path between sensors and sink. at the same time, we implement three different mobility patterns in thefield to efficiently gather data in our proposal protocol srP.
a key prediction of inflationary cosmology is a nearly scale - invariant spectrum of initial fluctuations composed of energy density ( scalar metric ) and gravitational wave ( tensor metric ) perturbations.   the two components leave imprints on the cosmic microwave background ( cmb ) anisotropy that are potentially detectable and distinguishable. in a recent paper@xcite, we computed the background evolution, the cmb power spectrum and the mass spectrum for qcdm models where a significant fraction of the energy density of the universe takes the form of a cosmic scalar field ( @xmath0 ) with an equation - of - state different from that of matter, radiation or cosmological constant. in the present paper, we compute the full, scalar plus tensor cmb Power spectrum for these models based on inflationary initial conditions and determine how the relation between primordial spectral indices and amplitudes predicted by inflation is modified by the presence of a @x Math0-component. using the standard notational convention, we find that the magnitude of the tensor contribution to the cmpb polarization contributions to be significantly larger for models with a Cosmological constants of 0.1 and 0.2 than
alice ( a large ion collider experiment ) at the cern lhc is planning a major upgrade of the central barrel detectors, including the tpc, to cope with the foreseen increase of the luminosity after 2020.   the current multi wire proportional chambers @xcite will be replaced by the continuously operated detectors employing gas electron multiplier ( gem ) technology@xcite. in order to fulfil the challenging requirements of the upcoming upgrade,   a novel configuration of gem detectors has been developed that allows us to maintain excellent particle identification and efficient ion trapping by stacking four gem foils operated at a specific field configuration.
the pole structure of the transmission of a one - dimensional periodic array of dirac delta potentials ( dirac comb ) is investigated in this paper.   the transmission amplitude of n unit cells is expressed by the transmittance of one unit cell. using the transfer matrix method the transmission coefficient of @xmath0 number of unit cells and the transmission probability of the system are derived for the case of Dirac comb. to find the quasi - bound states of the systems the quasi- and real - energy poles in the complex energy plane   are calculated numerically. an analytical expression is obtained for the imaginary part of the poles and it is shown that it scales with #@xmath9, where @x Math0 is the number of units in the system. on the other hand, the numerical results are excellent agreement with the analytical expression.
vector auto  regressive ( var ) models play an important role in contemporary macro  economics, being an example of an approach called the " dynamic stochastic general equilibrium" ( dsge ), which is superseding traditional large  scale macro  econometric forecasting methodologies  @xcite.   a challenging and yet increasingly important problem is the estimation of large covariance matrices generated by these stationary processes, since high dimensionality of the data as compared to the sample size is quite common in many statistical problems ( the " dimensionality curse " ). in this paper  , we suggest that such calculations can be considerably simplified by resorting to a mathematical concept of the free random variables calculus   @excite, which allows not only to rediscover, which much less strain, the two fourth  order polynomial equations obtained in @xcite in the @x Math7 and @xmath8 cases, but also to derive a sixth  order equation ( [ eq : varmaoneonemainequation ) which produces the mean spectral density for a more involved @x math6 model.. the results are verified by numerical simulations, which show a perfect agreement.
five experiments have measured solar neutrino fluxes that are significantly deficient relative to standard solar model expectations.   four out of the five experiments find overall fluxes in the range of @xmath3 of the theoretical predictions, while the chlorine experiment sees a larger deficit than expected ( ~2.5 ev@xmath4 ). 	 maximal mixing between the electron neutrinos and a sterile flavour has been proposed as the underlying explanation for these observations.    the purpose of this paper is to make a more detailed analysis of the maximal @x Math0 solution to the solar neut rino problem using two recent developments : ( i ) the clarification that a day - night asymmetry generically exists even for maximal mixing ( due to earth regeneration which affects the night - time events ) and ( ii ) the observation by superkamiokande of an interesting feature in the recoil electron energy spectrum for @xMath8 mev@xcite. here   we show that the present data rule out a wide range of the relevant @x math2 parameter. on the other hand, we find that the observed asymmetry is not an energy - independent factor of a half as previously advertised.  one of the
@xmath0  aur is a binary near the heliocentric julian equator of the far ir.   it is one of the most intriguing binary systems in the solar system and has been observed by many observers over the last few decades. here  , we analyze the spectroscopic eclipse of @xmath1  aur from the red spectral region covering h@x math1 using the following sets of spectra : 112 dao ccd spectra from 1994  2011 ( rjd = hjd-2400000.0 ) ; 292 ondejov spectra for 2006  2012 ( rJd  55600 ) ; and 15 lisbon spectra with the program fotel @xcite for the orbital solutions for the bisector rvs measured at various levels of the profiles obtained from the clean profiles of two strong metallic lines, si  ii  6347    to  6417   and fe ii  to -   6419   between 1994 and 2011  2012. while the general behavior of both lines shows similar patterns, one can note an extended blue - shifted absorption in phases near the third contact seen in the
active galactic nuclei ( agns ) are the central engines of active galactic centers and are surrounded by dust - tori.   the level of dust - obscuration of agn is correlated to the star formation activity, which has a peak at @xmath10 @xcite. in this review,   we discuss the recent advances in the search for buried agns in luminous infrared galaxies ( lirgs ) using infrared spectroscopy.
anisotropic quantum hall states with strong anisotropic transport properties in high landau levels ( lls ) have been observed in a fast rotating quasi - two - dimensional gas of polarized fermionic dipoles.   the states are of present interest, both theoretically and experimentally, because of their unique geometrical properties. by tuning the direction of the dipole moment with respect to the @xmath2-@xmath3 axis,   it is possible to obtain an anisotropy - dependent effective mass or anisotropical interaction between the polarization fermions and the spin - phase dipoles in the planer geometry. here   we explore the construction of a family of wave functions for these states using the unimodular transformation as a recipe to generate the anisotic many - particle states due to the unimmodular transformation. from the results of the experiments, we propose a generalization of the original laughlin wave function to the theory of fractional quantum hall anomalous hall states that are non - exact eigenstates of special 2-body hamiltonians consisting of projection operators, which depend on a parameter called guiding center metric. this new family of quantum hall wave functions
the first optical counterpart of gamma - ray burst ( grb ) was identified on 1997 february 28, 1997.   since then, more and more grbs have been optically detected, especially after _ swift _ was launched successfully, which allows early follow - up observations with ground - based optical telescopes. however, about 40 per cent of the observed grbs still failed to be identified with optical or infrared counterparts. for the nature of the dark burst,   several models have been proposed : extinction from dusty opaque star - forming regions, high redshift, intrinsic dimness, observational effect, as a result of the late response to the bursts. in this study, we report the case of grb 070518, which was detected by gamma -ray burst alert telescope ( bat ) onboard _ swift_ at 14:26:21 ( ut ) on may 18, 2007. it is a rare type of optically dim grb with a faint optical afterglow, and its optical luminosity distribution shows a bi - model phenomenon : optically luminous and opticallydim.    the values of duration mean the burst belongs to the short tail of the long group, and the ratio of fluence
the storage, processing and retrieval of visual information are first order tasks for researchers in the discipline of image processing and related areas such as pattern recognition and artificial intelligence.   however, due to the restricted architecture of classical computers and the often overwhelming computational complexity of state - of - the - art algorithms, it is necessary to find better ways to store, process and retrieve visual information. in this article   we review some of the more general principles of quantum information before specializing in later sections to the subject of image storage and retrieval.
the decision to refinance a mortgage is often undermined, and unfortunately, misunderstood by many homeowners.   we present a synthetic mortgage calculator that simulates the monthly payments associated with a traditional mortgage, and the proportions of the mortgage that are allocated towards the interest and principal payments. upon completion of this mortgage calculator, we will extend its features, and simulate scenarios of refinancing. in each scenario,   the initial costs are eventually overtaken by the savings in decreased monthly interest payments. as we will see, there exists a threshold for the time remaining on the mortgage to validate the net present value of such a decision.
coexistence of two or more order parameters in solids is one of the most intriguing phenomena in condensed matter physics.   a very popular subject of research are compounds with coexisting superconducting ( sc ) and magnetic ( m ) order parameters. here   we present a new method for the study of the josephson effect in junctions based on pnictides, which is based on the so - called quasiclassical green s functions that are obtained by integration over the modulus of the momentum in the vicinity of the fermi surface at the interface between the electron and hole pockets corresponding to the sc and m order parameters.the results of the study are presented in terms of the equations for the green s function, which are written in the mean field approximation in an analogy with the ordinary superconductors without specifying the microscopic mechanism of superconductivity and were solved under some approximations mostly in spatially homogenous cases.    the results are compared with the results from the theory of superconductor / normal metal structures where the ordered phases are even antagonistic to each other.
column densities in molecular clouds ( mc ) are estimated using the integrated antenna temperature of optically thin rotational transitions such as the j=1@xmath50 line of @xmath0co under the assumption of local thermodynamic equilibrium.   the lte calculations are based on a set of approximations that varies from work to work concerning the way to estimate excitation temperatures ( @x Math7 ), the partition functions ( @ xmath8 ), and optical depths ( @Xmath9 ). in this paper  , we show that the true @x math0co column density is underestimated by the usual lte approximation. for the purpose of this work   we use six cloud models from the catalog of artificial clouds by padoan et al. ( 1997a ) containing grids of spectra of different molecular transitions of j = 1@xMath50 @x maths0co and @x mathematics11co lines from three 5  pc diameter artificial clouds and from three 20  pc clouds.. the effect of complexity on the resulting spectra is investigated here. over most of the calculated volume, the @x mathematician0co rotation transitions are sub - thermally excited in
particle - in - cell ( pic ) simulation of plasmas is a powerful technique for studying plasma phenomena, in large part because it can include all of the classical " first principles " physics  . however, the strength of pic is sometimes its biggest drawback, because simulations are often limited by what one _ can _ simulate rather than what one wants to simulate.   a new pic - based simulation technique  speed - limited pic ( slpic )modifies the pic method to slow down fast phenomena, enabling larger timesteps while retaining the same underlying physics on slow timescales. here   we show that slpic can be implemented as a minor modification to an existing pic code and that it has the potential to speed up simulation of phenomena that are numerically troublesome, but physically unimportant.
the rosat all - sky survey ( rass ) has produced a statistically complete sample of x - ray emitting clusters with a limiting flux of @xmath17, which is at least 75 percent complete at the 90 percent level.   this sample is based on analysis of the data base of the rass-1 and bcs surveys, and contains a total of 201 clusters. in this article   we describe the progress made in the production of these samples, and discuss the advantages and disadvantages of each phase of the analysis.
the tmt project conducted an extensive site monitoring campaign to identify the most suitable site to host the observatory.   the tmt site testing employed combined mass - dimm instruments ( @xcite ) to assess the low resolution turbulence profile ( tp ) through the entire atmosphere. in order to measure the tp within the lowest few hundred meters above the sites, acoustic turbulence profilers ( sodars ) ( sound detection and ranging ) were also employed. here   we report on the results obtained with these turbulence profiler during the t mt site testing.
the quantum phase transition driven by quantum fluctuations is one of the fundamental issues in quantum many body systems.   a number of novel phenomena associated with the phase transition such as the quantum critical behavior have been observed in a variety of condensed matter materials, including the one - dimensional spin-1/2 ising lattice with a transverse field, namely the transverse ising model ( tim)@xcite. in this paper  , we study a class of high spin quantum ising models with single - ion anisotropy, defined by the following hamiltonian terms : @xmath11 where, @x Math12 is the single - ions and @x math13(@xmath14 ) is the site - dependent spin operator at each site on the lattice. based on the exact solution, we show that for a given hole configuration, each sub - lattice system with purely polarized spins can be exactly solved in that case. depending on the strength of dimerization, we find that the system undergoes a quantum phase transitions where the criticality is the same as that of the uniform @x maths0 tim. for the systems with local moments larger than @xMath7, the quantum phase
we present an analytically solvable nonlinear @xmath0 symmetric eigenvalue problem that models stationary states of a bose - einstein condensate in a two - mode potential.   this is the stationary version of a model introduced in @xcite as the mean - field limit of a @x Math0-symmetric two - modes many - boson system, which has been extended to include up to four eigenstates for arbitrary parameter values. here   we extend these results to give expressions for the corresponding nonlinear eigenvalues, and analyse the breakdown of @x math0-Symmetry in this nonlinear model. with the exception of isolated exceptional points at which two stationary states coalesce,   the model can be interpreted in terms of a linear matrix model. using the time - independent model, we investigate the stability of the stationary solutions, and show that for low temperatures, the dynamics of the quantum systems are stable.
the optical spectra of two actinide dioxides, uo@xmath0 and puo@x Math0, are investigated using the gga+__u   scheme.   the band gap and high - frequency dielectric constant for uo @xmath4 and pao@x math0 are calculated to be 2.3 ev and 5.53 ev, respectively, which are in good agreement with the experimental values of about 2.1 ev and5.1 observed in the optical spectroscopy of @xcite, respectively. moreover, our calculated dielectic function @x maths6 exhibits the overall agreement with experimental result and the main peaks are well reproduced.    the dielectrics of uo=xmath8 and poo@xMath0 are also calculated using the projector - augmented wave ( paw ) method of blchl@xcite as implemented in the ab initio total - energy and molecular - dynamics program vasp. based on the results of these calculations, we predict that the optical behavior of puo<xmath9 can be used as a useful reference for future experimental measurement.
we report the sixth detection of carbon monoxide ( co ) around a debris - hosting star, hd 32297.   the molecule was detected by millimetre rotational transitions at 450 and 850 micron wavelength in the far - infrared from the 15 m james clerk maxwell telescope at mauna kea, hawaii, using weak cii emission as a predictor for the presence of co.    we also show that the distribution of co is spatially asymmetric, with the star's position within the gas - plus - dust system being more closely related to the star than expected from model predictions.
the high pressure and temperature equation of state ( eos ) of carbon in the range from @xmath3 mbar to 20,000 k has been studied using density functional theory ( dft ) molecular dynamics ( md ) simulations.   the results are compared with experimental data obtained with magnetically - driven flyer plates and laser - shock and ramp - compression experiments, as well as theoretical work on the eos and phase diagram of carbon at pressures between 10 - 1000 mbar. a new approach to describing the electronic structure of the high-@xmath4 plasma state is presented which uses a combination of ab initio electronic structure techniques of the dft variety together with a random search method to find the thermodynamically stable crystalline phases at pressures ranging from 10 to 1,000 mbar @xcite. by combining these two approaches,   it is shown that the proposed eos model can be used to predict the states of compression reached by the ablator material for inertial confinement fusion at temperatures in excess of tens of ev.
chiral symmetry plays an essential role in qcd and electroweak theories.   it is a global symmetry which forbids an additive quark mass renormalization and whose spontaneous breakdown provides us with ( nearly ) goldstone bosons with their specific interactions. for the electroweak theory,   chiral symmetry is a local gauged symmetry which is necessary to provide a renormalizable theory. when trying to regularize these theories on the lattice, one meets two basic problems : ( 1 ) one can not realize chiral symmetry exactly on the atomic lattice without sacrificing some even more important principles, like locality or absence of extra physical particles. here   i discuss the ginsparg - wilson ( gw ) relation and its consequences for the non - perturbative regularization of chiral gauge theories at finite lattice spacing.
the consistency approach to the lattice equations @xcite is of great interest in the field of partial differential equations.   one of the highlights of this approach is the immediate existence of a lax pair and bcklund transforms ( bt ), which can be directly constructed from the " side - equations " of the cube@xcite. in this paper   it is of interest to take a closer look at the lax pairs, bck Lundgren transforms and consistency, and investigate what they are good for. in particular  , we find that in some cases the zero curvature condition ( zcc ) yields two different equations that can be used to define rational evolution in the square lattice. by constructing discrete systems over a larger sub - lattice of the original lattice, we push the use of @xmath0-matrix lax pairs to its limits, by building discrete systems with the same equations on all six faces of a lattice given by multi - affine relations. using the example of the consistency - around - a - cube ( cac ) construction as a starting point, we show that the existence of the lax pair results in the formation of a set of integrable partial difference equations
geomagnetism is still one of the unsolved fundamental problems of the earth.   recent numerical simulations of magnetohydrodynamics ( mhd ) for geomagnets seem to describe such dynamics. in this paper  , we would like to develop the above idea by elaborating the domino model in a form that is _ minimal and general_.   in order to construct the _ minimal _ model, we introduce a _ long - range coupling _ of macro - spins, i.e. all the spins interact with each other with the same amplitude of interactions. it turns out that this long - ranges coupling model is also effective to describe the observed features of geomataly as the domineo model. on the other hand,   magnetic fields associated with celestial objects are quite common in the universe ; many planets, satellites, and the stars including our sun.    therefore we try to fit our model, supplemented with mhd equations, in _ other celestial objects _ and see how they are consistent with each others. 	 the long - Range coupled spin model can also describe the _ synchronization _ physics as well if we simply change the parameter value in the model., furthermore the long
we use near - infrared integral - field spectrographs ( nir ifu ) to study the gas flows in the centers of two megamaser disk galaxies, ngc 4388 and ngc 1194, which are located in virgo and kuo et al.   ( 2012 ), respectively. using these two galaxies as a model system, we show that the molecular gas flows on @xmath7  pc scales are very different from those observed in the center of active galactic nuclei ( agn ) of the same galaxy with a single bh ( ~1.5 billion parahippocampal mass ) on @xcite. for the first time, we find that the rotational motions of the gas in the accretion disks of the two galaxies are directly correlated with the gravitational sphere of influence of the central bh, and that the gas flow in the mergers is dominated by rotationally dominated gas on@xmath2   pc scales rather than by bar - like gas on au scales.
we present a set of chemically consistent spiral galaxy models with a range of star formation histories ( * sfhs * ) specifying the spectral types @xmath0.   our models are very simple 1-zone models without any dynamics meant to describe global quantities of average galaxies of the respective types. in order to see how far we can get and what kind of sophistication is required by a comparison with observed galaxy properties, we compare abundances for a series of elements observed in damped ly@xmath1 ( * dla * ) absorbers over the redshift range from @x Math2 through @x math3, which corresponds to lookback times of more than 90 % of the age of the universe.. we then present the spectrophotometric properties of those galaxy models that succesfully describe the dla galaxy population and discuss them in the context of the large campaigns designed to optically identify dla galaxies both at low and at high redshifts.
strong interactions between rydberg atoms can affect the coherent manipulation of a large group of atoms so it is necessary to use a many - body treatment to evaluate the fidelity of quantum information protocols. in this paper   we consider mesoscopic samples of @xmath410@xmath3 diameter containing up to 100 ground - state atoms which are excited by single photon transitions to high @x Math5 rydburg states.   the influence of the interactions between atoms on the dynamics of the excitation process is investigated. at high principal quantum number @x math2,   strong interactions between these atoms inhibit the excitations of many surrounding atoms within a range of few @x maths3.. the atoms within this range are strongly correlated so that a many-body treatment is, in general, needed.    we study in detail the dynamic dynamics of such systems, especially the possibility of many -Body rabi oscillations of rydberg excitation.
we report the performance of a new x - ray matrix calorimeter for the mu2e experiment @xcite with electron and photon beams.   the energy scale has been set by comparing the total reconstructed charge in the matrix with the expected energy deposited in the entire matrix, @xmath16, as estimated by a geant4 simulation. besides the beam spatial spread, an additional constant 2.6% gaussian smearing is needed in the simulation to reproduce real data, accounting for miscalibration, non uniformity and non linearity. at the same time, the intrinsic energy spread of the beam has been obtained by comparison the energy resolution of one - particle and two - particle events. after subtracting@xmath17 from the calculated energy resolution, the resulting parametrization on monte carlo simulations is reported as a function of the deposited energy.
in 1962 bchi introduced nondeterministic automata on infinite words, which are a natural tool to model things that happen infinitely often.   the problem of comparing the power of different types of automata is well studied and understood. in this paper   we consider the problem about the number of states needed to simulate a bchi automaton by a co - bchi Automaton ( if such an automaton exists ) left open in @xcite : given a number @xmath8, for what@xmath9 can we be sure that every non - deterministic b chi automaton with no more than @x Math0 states, which can be simulated by a Co - bchi automaton, can be simulated by one with at least @x math9 states?   there is a large gap between the known upper bound and the known lower bound for such a translation. in order to find a lower bound, we use the best currently known translation of the problem involving intermediate deterministic street automaton via exponential blowup of the number-of - states, involving the transition relation between the two types of auto - automata. as a result  , we find that for each @x
the study of vibrating plates has attracted a lot of attention in the last few decades.   the experimental study of these plates has turned into studies on billiards, where a point particle moves freely inside an enclosure, reflecting specularly from the boundaries in accordance with the snell s law. here  , we present our study on this system by making extensive numerical investigations. through this analysis,   several interesting conjectures are made and connections with the symmetry group and statistical studies on domains are also given. as shown in @xcite, the distribution of nodal domains can serve to distinguish between systems which are separable and non - separable, and the limiting distribution, which always exists for separable domains, can give a new criterion for chaos in quantum mechanics.
supramolecular chemistry is a promising approach to achieve three - dimensional control of intermolecular interactions in the solid state.   it allows the design of extended complex structures built through the hierarchically ordered assembly of elementary building blocks in solution prior to the casting process using non - covalent interactions such as hydrogen bonding and @xmath0@x Math0 interactions. here, we investigate resonance energy transfer ( ret ) kinetics in two pairs of oligo-_p––phenylenevinylene ( opv ) derivatives : oligo-(p––methyl-2,4-diphenylphenylene)phenylene ( mopv ) and bisphenol-2-phenylene-1,2-picrylhydrazyl ( bopv).we find that the ret kinetics of the exciton diffusion mechanism in these systems are similar to those in conjugated polymeric semiconductors, where the excitonic energy levels in an h - like aggregate are distributed in a weakly coupled manner. by raising the temperature,   the distance between the opvs increases but the result is the stretching of the frustrated stacks and not a complete break - up, as is the case
we study the out of equilibrium dynamical properties of a two dimensional ising model of a ferromagnetic thin film with perpendicular anisotropy in which the magnetic moments are oriented perpendicular to the plane of the lattice.   the system is modeled by a system of magnetic dipoles on a square lattice, with both nearest - neighbor exchange interactions and long - range dipole - dipole interactions between moments. for the range @xmath12 the system presents a first order phase transition between a low temperature stripe phase and a high temperature tetragonal phase with broken translational and rotational symmetry, while for the narrow window around@xmath13 the model shows an intermediate nematic phase, between the stripe and tetragonagonal ones, where the system has short range positional order but long range orientational order.    we show that under a cooling from high temperature no metastable tetr diagonal states are observed, but the system shows a strong metastability in the nematic phases. here   we perform quenches of the system from initial conditions at high temperatures directly to the stripe phase using the dimensionless ising hamiltonian ( / =
the lindhard model of the nuclear recoil energy of low - mass cold dark matter is well known to the dark matter direct detection community.   it is widely used to predict the quenching of recoiling target atoms ( " nuclear recoils " ) following a scattering event, and is generally accepted as the most accurate model for this regime. however, the validity of the model in any material is questionable at very low energies. with the exception of germanium,   reconstructed energies smaller than a few kev must rely on a model. here  , we examine the sources of this uncertainty, undo a simple approximation of the original treatment, and obtain a new solution of theOriginal model in the energy range of interest for low - Mass dark matter : @xmath6 ( generally, @x Math7 less than aFewkev ).. the new model is based on the fact that the amount of electronic excitation produced by a recoiled atom is quenched by approximately @x math4 or more relative to a recosmally excited electron of the same energy. using data from experiments such as the g2 experiments lz and supercdms snolab,
mesoscopic systems of the cylinder symmetry ( like rings, toroids and cylinders ) of a cylinder symmetry are threaded by a magnetic flux.   the system is characterized by a stationary solution of the fokker - planck equation describing the dynamics of the magnetic flux in the system. at zero temperature,   a part of electrons becomes normal ( non - coherent ) and the amplitude of the persistent current decreases. at non - zero temperature for the system under consideration, there are both coherent and dissipative parts of the total current, namely, the persistence current and the non - dissipative current. to answer this question, we exploit the so called quantum smoluchowski equation introduced in ref. and, with the maxwell daemon successfully exorcised, in refs. first and second  , we extend our model for overdamped kinetics @xcite to the domain where charging effects ( corresponding to the inertial effects for particles ) appear.it is shown below that in moderate, with respect to the gap at the fermi level, temperatures these quantum corrections are destructive for their existence. it is not the case at lower temperature : one gets not only the multistability of the probability density but also significant enhancement of
v446cephei ( hd 210478 ; bd+60@xmath92348 ; hip 109311 ; v=7 @xmath10.32, b - v=0@x Math10.08 ) is an algol - type eclipsing binary ( ea ) with a hot component.   it is one of the members of the cepob2 association. in this paper   we present new spectroscopic observations of v446cechei and evaluate effective temperatures and surface gravities of the component stars from an ad - hoc analysis of the spectra taken near the quadratures. combining the results obtained by the analysis of radial velocity ( rv ) and light curves we determine directly absolute masses and radii of the components using the method of direct measurement of the mass and radius of the system.    the results show that the mean effective temperatures of the two components are about 4.8  kj / cm2 and 2.1  km / s for the star with a mean mass of 7.5  cm2, respectively. 	 the minimum temperature of the star has been determined to be 5.4  kJ / cm
the formation of vortex tubes in the intergranular lanes of the quiet sun has been observed by high - resolution solar telescopes.   recent radiative hydrodynamic simulations have shown that vortex tube formation in the near - surface layers can be caused by two basic mechanisms : 1 ) small - scale convective instability developing inside granules, and 2 ) the kelvin - helmholtz instability of shearing flows. in this letter, we present new numerical simulations of the solar atmosphere using a 3d radiative mhd code ( ` solarbox') developed at the nasa / ames research center and the stanford center for turbulence research by alan wray and his colleagues @xcite for modeling the outer part of the subgrid - scale solar convection zone and lower atmosphere in a cartesian geometry with a smagorinsky eddy - viscosity model of the turbulent subsurface layers of the photosphere and chromosphere. to better understand the dynamics of penetrating vortex tubes, we show that the energy transfer from the solar interior to the solar upper atmosphere is dominated by radiation and flows, and that the shape of the vortex tubes is influenced by the direction of the radiation and flow.
the standard model ( sm ) has been tested at an unprecedented level of precision by various experiments, but some excesses have not yet been completely resolved.   the first excess is the muon anomalous magnetic moment ( muon @xmath3 ), where the discrepancy between experimental data and the sm prediction currently is @x Math8  @xcite.    the second excess is that a resonance with a mass of 750 gev in the diphoton invariant mass spectrum was indicated by the atlas  @xcite and cms  @xaite experiments ; however, the width and spin of the resonance are still uncertain. to resolve the excesses in a specific framework, we propose the extension of the sm by including leptoquarks ( lqs ) and one higgs singlet, which are colored scalars that simultaneously couple to the leptons and quarks, and the 1h-1h-2h-4h-7h-6h-8h-9h-10h-11h-12h-13h-14h-15h-16h-17h-18h-19h-20h-21h-22
in a recent paper, kiritani _ et al.   reported that a large number of vacancies were produced during high - speed heavy plastic deformation of thin foils of fcc metals @xcite.    they observed a large density of stacking - fault tetrahedra but very low dislocation densities in the foils after deformation. as a possible explanation, they propose a dislocation - free deformation mechanism. in this paper   we investigate the deformation processes in metals under very high strain rates using molecular dynamics ( md ) simulations. to get meaningful results from a molecular dynamics simulation, it is essential that the interatomic forces used in the simulation are a good approximation to the forces the atoms would experience in a real physical system with the same atomic configuration. for this purpose, we use the effective medium theory ( emt )@xcite to describe the interactions between the atoms in two different systems of copper. in the smaller system,   four vacancies were created in the initial configuration, by removing four random atoms. at 450 k, the system is deformed along the  direction at a temperature of 450 k. the first dislocation activity appears in the form of a
in a recent article @xcite the following conjecture was formulated : consider an asymptotically flat, vacuum, complete axially symmetric initial data set for einstein equations.   then the following inequality holds : where @xmath0 is the area and angular momentum of a connected component of the apparent horizon. in that article   evidences for the validity of conjecture  were presented. in a particular class of initial data sets, called extreme throat initial data, the first variation of the area, with fixed angular momentum, is zero and the second variation is positive definite evaluated at the extreme kerr throat initialData. here   we present a complete and optimal answer to the conjecture by using theorem  .the main result is that the area of theextreme kerr neck initial data is a minimum among this class of data. since it is well known that a non - negative second variation can not be considered as a necessary condition for a local minimum ( which is, of course, what we need to prove ), we extend the result to include the physically relevant asymptic flat black hole initial data mentioned in the conjecture.
the standard model of low - mass star formation in molecular clouds assumes that the core of a molecular cloud undergoes quasi - static fragmentation by ambipolar diffusion until it becomes supercritical, and then collapses on a dynamical timescale to form either one or a small multiple system of stars.   this model is supported by the observation that the age spreads of young stars in nearby molecular clouds are often a few years @xcite, and the low fraction of clouds that are observed to be in a pre - star - formation state. in this letter  , we study the three - dimensional extension of the@xcite model, by including a self - consistent calculation of the vertical structure and dynamics of the cloud. using supersonic turbulence as a parameter, we show that the timescale of core formation in subcritical clouds can be significantly shortened by reducing the size of the magnetic field and the initial mass - to - flux ratio, and that the scaling of various physical quantities allows this to occur.
the observed accelerated expansion of the late - time universe, as evidenced by type ia supernovae ( sn - ia ) and the cosmic microwave background radiation, has been attributed to a dark energy component.   it is well known that any expansion history can be generated by choosing a suitable equation of state for the dark energy ( parametrised by the hubble parameter @xmath0 ) and that this can be used to predict the evolution of the dark matter perturbations in a standard cosmological model with dark energy. recently   there have been claims that it is instead possible to use the growth rate of structure for this purpose. here   we show that this assumption is not sufficient to distinguish between dark energy models and modifications of gravity. using the dvali - gabadadze - porrati ( dgp ) brane - world model as an example  , we find that the growth rates of structures do not need to be more than 1.5 times faster than the observed growth rate in order to reproduce the effects of dark energy on the metric perturbation in the 3 + 1 dimensional metric. however, we also show that the results are based on assumptions about the nature
we extend the bogoliubov theory for the description of bose - einstein condensation and the quantum phase transition for nonrelativistic bosons in arbitrary dimension @xcite to a nonvanishing temperature.   we present a quantitative rather accurate picture of this behavior in three dimensions, and find that the theoretical framework is valid for most quantities.
a recent work@xcite has shown that a reduced description of the energy landscape, originally devised for the analysis of super - cooled liquids by stillinger and weber, can successfully capture the essential thermodynamic aspects of folding in the context of a simplified protein model.   this finding is important because it provides a general scheme for theoretical studies of protein thermodynamics, showing how the relevant information can be quantitatively accessed from its imprint on the potential energy surface. however, the validity of an analysis based on the inherent structure landscape ( isl ) must be critically examined because the method involves a fundamental assumption which could be questioned : the vibrational free energy within the basin of attraction of an inherent structure is assumed to be independent of the basin. in the present work, we show that, even when the vibratory free energy depends on the energy of the inherent structures, the derivation of thermodynamic quantities such as the specific heat from the isl can be validly carried out without any change in the procedure. in a second step  , we critically revisit the major hypotheses of the isls approach, as well as its practical limitations, including the sampling of the phase space, and suggest routes for improvements. finally, we summarize
model predictive control ( mpc ) is a consolidated control technique that can efficiently handle constraints on the process to be controlled.   nevertheless, its application is not yet widespread in many domains where real - time computational constraints and requirements of certified solutions are of major concern, such as aerospace or automotive applications. in this paper, we explore the use of parallelization techniques to efficiently solve a typical mpc problem for a linear discrete - time system, with a substantial computational speedup compared to nonparallel implementations. our proposed algorithm combines the using of alternating direction method of multipliers ( admms ) to handle the coupling constraints that arise from the dynamics of the system and inexact solvers ( i.e., solvers that guarantee feasibility and optimality only _ asymptotically _ with the number of iterations ). here  , we propose an online update strategy of the tightening parameters that guarantees recursive feasibility, suboptimality, and closed - loop stability.
the quantum renormalization group method is introduced and used for the ising chain with antisymmetric anisotropy and alternating exchange interactions.   the renormalized ground state can be obtained analytically. in the quantum phase transitions, the quantum criticality at the ground state of the model is characterized by the energy of the renormized ground states which are approximately represented by the discontinuities in the derivatives of some order parameters. according to this method, the entanglement entropy and the divergence of the derivative of entropy at the same critical points   are found to be related to the quantumcriticality.
tail - biting trellises are perhaps the simplest instances of decoding graphs with cycles.   usually approximate algorithms iterate around the trellis until either convergence is reached, or for a preset number of cycles. to the best of our knowledge,   no _ exact _ decoding algorithms have been proposed so far for the general case, though there are several _ approximate _ algorithms for maximum - likelihood decoding and exact algorithms for bounded distance decoding. in this paper   we propose an exact recursive algorithm for tail - biting Trellis based soft decision decoding using the @xmath0 algorithm which is based on the fact that a linear tail - bite trellise can be viewed as a coset decomposition of the group corresponding to the linear code with respect to a specific subgroup and is based at least in part on the @xcite algorithm.    we also propose two approximate variants of the same algorithm that always converge, and observe their performance on tail - bit error rates for the ( 24,12 ) extended golay code and two convolutional codes of rate 1/2 and memory of 4 and 6 respectively.the performance of the first approximate variant is indistinguishable from that of the exact algorithm in terms of
while string theory has had remarkable successes over the last several years, it is still very much the case that we do not yet know what the theory is.   we have found that there is a larger framework into which the type 0a and type 0b string theories can be naturally embedded, and within which they are connected as parts of a larger theory. when perturbation theory is examined, other special points suggest themselves, and they turn out to be just as " stringy" as the original type  0 theories, deserving to be thought of as string theories as well. in this paper  , we begin the program of trying to identify some of these theories, with some success, and find that the larger framework provides natural definitions of regimes of the type  1 string theories that are hard to define using perturbative theory, and we will report more fully on them in a follow  up to appear later@xcite.
a hybrid photonic device combining two photon - pair sources and a dynamically configurable optical circuit capable of heralding the emission of engineered two - photon states at a telecom wavelength is demonstrated.   the hybrid device is based on femtosecond - laser - direct - written waveguides ( fldw ) on glass and lithium niobate ( ln ) waveguide technologies coupled to non - linear waveguided ( ppln / w ) nanostructures, which allow generation of non - degenerate photon pairs at the telecom wavelengths of 1310 nm and 1560 nm in each waveguide using type-0 spontaneous parametric down conversion ( spdc ). by virtue of its 3d reconfigurable nature,   this device can be used to engineer and herald any desired path - coded quantum state for quantum sensing and computing applications.
quantum walks have been a particularly fruitful field of research in quantum information.   one focus of recent work on quantum walks is their application to spatial search algorithms. in @xcite, we demonstrated that effective searches over two - dimensional lattices may be achieved in an arguably simpler way which does not require extra degrees of freedom, and could, therefore, be viewed as more efficient. this is achieved through the choice of a different lattice, specifically, a honeycomb lattice which is the underlying lattice structure of carbon atoms in the material graphene. in this paper, we offer a detailed account of the theory and numerical results thus expanding on the findings as presented in@xcite. using the quantum walk and quantum search algorithm framework  , we show that additional site perturbations can be used to create a search protocol for graphene using a continuous - time quantum walk model. while the search running time and success probability are not significantly different from those of discrete - time searches, the search protocol can be adapted to demonstrate novel communication setups.
in the present paper it is shown that we can reverse experiment arrangement to study spin rotation and oscillation of particles of a gas target, through which a beam of high energy particles passes.   this technique is based on the effect of proton ( deuteron ) beam spin rotation in a polarized nuclear target and ( it is very important)on the phenomenon of deuterons spin rotation / oscillation in a nonpolarized target..the experimental results show that the angle of spin rotation of deutron spin can be experimentally observed by the measurement of the effective potential energy of a particle captured to a gas trap under the action of a beams of polarized particles.
the high energy cosmic ray events recorded with x ray emulsion chambers ( xrec ) at very high altitudes are not contained events ; the origin of the collision can be only approached by the invariant mass of the @xmath1 s and sometimes by the geometry of the most energetic subcascades.   the observation of the abnormal fluctuations in the pseudo rapidity distribution and the coplanar emission of hadrons in the air shower data from the lhc experiments is a striking feature of the event jf1af1, a p - al collision which is characterised by a near perfect alignment of all the cascades with energy exceeding 50 tev during the exposures on the concorde and strana during siberian balloon flights. after extensive simulations, we have shown that alignments may appear in the emulsion chamber data of these events as a result of the formation of hot spots of quark - gluon plasma.
the galactic centre region (  gcr  ) is a dramatic region of the galaxy with remarkable properties, and it is not surprising that the cosmic ray (  cr  ) view has singular interest.   we have examined the implications of cosmic ray acceleration in supernova remnants ( snr ) for a wide variety of cr phenomena, including the existence of a black hole of mass in the central parsec. using hess gamma ray spectroscopy  , we have now studied the gcr in sub - tev and tev gamma rays from several sns in the region sgrb2. the results show that the energy densities of the plasma, the far - infra - red radiation, magnetic fields and gas motion are all several thousand times higher than those found locally at @xmath12, and the magnetic energy density will be higher still over limited volumes. as a result, the intensity of the gamma ray signal from this region is much higher than that from the same region at ~100 mev, and there is a strong case for such acceleration providing the bulk of the cr up to @x Math15.
we examine defects that are defined by a nontrivial mapping of the brane positions in extra dimensions.   these defects are called " primary brane defects " because they are constructed from a non - contractible winding ( or wrapping ) of a brane position around extra dimension(s ) and the parameter of the mapping is defined by absolute coordinate in the compactified space. in this paper, we discuss the cosmological evolutions of these defects in the context of string theory.
the jewel  @xcite heavy ion generator is a powerful tool for studying the complex nature of energy loss in medium - jet interactions.   it can be used to reconstruct the final state medium modified jet evolution on dijet events generated by pythia6 @xcite using a combination of the lpm effect and the mc version of the light - phase effect  . the recoiled partons that scatter upon interaction with the scattering centers are known as the recoil partons, which are removed from the data but still carry with them the thermal component of the scattering center.. this mismatch arises when comparing observables estimated using jewel with recoils to data due to the systematic removal of the fluctuating heavy ion underlying event in data, whilst in jewel the recoilPartons still carry the thermal components of the scattered scattering centers. in this report  , we look at the recent developments to the jewel  =  @xmath0 analysis framework and how a careful treatment of the background and its subtraction, along with an estimation of the systematic uncertainties involved, leads to a better comparison with data and the physics that can be extracted from the results.
the sagittarius dwarf galaxy ( sgr ) and its associated tidal stream have been the focus of much study in the last 20 years.   however, since the structure is yet to be fully mapped, it is not known whether there is an extended sgr stream / tidal - tail within the halo. here   we present a new analysis of the sdss data covering @xmath4, @x math5, @Xmath6, @ xmath7, @xxmath8 and @x Math9 using a combination of photometrically selected blue horizontal branch ( bhb ) stars and numerical simulations of the sgr system.. the results show that the observed features are consistent with the existence of a sgr trailing tail at galactocentric distances of ~60 - 80 kpc across the sky for all three of the studied regions.    additionally, we find evidence for a feature visible along the s gr plane which is likely to be related to the presence of a tidal stream.
the origin and evolution of aromatic carbon structures in the interstellar medium ( ism ) are poorly understood.   the presence of polycyclic aromatic hydrocarbons ( pahs ), including aromatic rings, in the ism raises the possibility that biologically significant molecules may exist in the space - time - scales. to date, most theoretical studies of formation of larger aromatic carbon chains, rings, and cages in ism have been done close to equilibrium and at relatively high particle densities. here  , we present a dynamical simulation study of the formation of c@xmath7, a ring - like carbon structure, from naphthalene ( c @xmath1h@x Math2 ) in the atmosphere of tc1 planetary nebula, which is thought to be of extraterrestrial origin. using a combination of density functional theory and molecular dynamics simulations,   we show that c@Xmath7 can be formed in a top - down manner in successive de - hydrogenation of pahs into graphene, with the first step occurring at low - temperature conditions, where vibrational distortions of the structures during their growth are minimized. under such conditions, no significantly curved ( cage - like ) structures are supposed to
floating electrons in a nanodiamond are discussed in this paper.   surface localization of electronic density agrees with the peels scan of a single nanod diamond ( 5 nm diameter and length = 1.5 - 2.5 nm ), which shows that unpaired electrons exhibited in described experiments belong to surface states of a 5 nm diamond ball. using born - oppenheimer approximation nucleus positions   is used to find surface states for each atom layer of a nano - diamond ball by solving the schredinger equation for the kronig - penney potential. as a result  , it is found that electrons can be localized on the surface of the diamond ball at the same energy as the electron on atom or nv - center. also, we show that the g - factor of a unpaired electron in ananodiamond is @xmath1, which is closer to free electron ( @x Math2 ) than to localized electron onatom (@xmath3 ) or nV - center ( @xcite ). 	 this explains spikes ( two oppositely charged layers ) which depend on the size of detonation nanodDiamonds.
the origin of the pulsar velocities is still unknown.   two classes of mechanisms have been suggested : ( 1 ) the first relies on convective instabilities in the collapsed stellar core and within the rebounding shock, and ( 2 ) the second relies on the asymmetries in the matter and temperature distributions associated with the instabilities. here   we show that the first class is not the only one, and that the second class is also not the most likely to be the cause of the observed pulsar velocity distributions. using a new method for the measurement of the birth velocity of neutron stars, we find that the latter class is more likely to explain the observed pulses than the former. as a result,   the results are consistent with the view that type ii supernovae are nonspherical and that neutron stars receive large kicks at birth.
we reexamine the fine - tuning problem of the inflaton potential in type iib string theory using flux compactifications.   we show that it is possible to achieve 60 e - foldings of inflation without any additional corrections to the potential for a range of values of mobile mobile mobiles branes, generalizing the simplest case of only a single brane playing the role of an inflaton. within this range, we observe a very interesting phenomenon, whereby starting with a sufficiently large number of mobile phones branes dynamically leads to a sufficiently flat infaton potential.    this effect is explained by the fact that the rate of inflation is controlled by the distance between the mobile mobile phone branes and the antibrane in the warped throat, which is tunable by adjusting the warp factor of the throat and the khler modulus.
dense plasmasks have recently gained growing interest due to their relevance for the interior of giant planets as well as for laser interaction with matter and inertial confinement fusion scenarios.   a fully selfconsistent treatment of these, in general, highly nonequilibrium electron - ion plasma has not been possible so far due to the requirement of the simultaneous account of electronic quantum and spin effects together with the ( possibly ) strong ionic correlations. here   we present an analysis of the potentials of weakly correlated electrons that can be derived from quantum kinetic theory @xcite by linearization in the external perturbation using a quantum hydrodynamic model ( qhd ) and replacing the linear response potential of the ions by a simplified expression that is derived from linearized qhd ( lqhd ), @xmath6. the results show that the se potential is qualitatively different from the kinetic results and that the stanton and murillo potential is in agreement with the random phase approximation ( rpa ) resulting from the mermin dielectric function at . however, the am and sm potentials are in good agreement with both the rpa result and the experimental results.
the equal - time cross - correlation matrix has been studied extensively for a variety of multivariate data sets across different disciplines such as financial data, electroencephalographic ( eeg ) recordings, magnetoencephalography ( meg ) recordings and magnetic resonance imaging ( mri ) recordings. in this paper  , we extend previous complex systems research, by examining time and scale dependent dynamics of the correlation matrix, in order to better understand the ever - changing level of synchronisation between financial time - series.   the results show that the correlation structure is well defined at high frequency, while for the original data the structure emerges at longer time horizons, ( using stocks from the new york stock exchange ). through the use of wavelet multiscale analysis, it is shown that the magnitude of the changes in relative eigenvalue size found at both ends of the eigen value spectrum, are market dependent, with the effects of varying data granularity not examined.
the evacuation of tsunami evacuees in large japanese cities near the coast has become an urgent issue. to determine appropriate evacuation buildings, we need to consider where evacuation buildings are located and how to partition a large area into small regions so that one evacuation building is designated in each region.   this paper focuses on the location problem of the evacuation building assuming that we fix the region such that all evacuee in the region are planned to evacuate to this building. in order to represent the evacuation  , we consider the _ dynamic  setting in graph networks, which was first introduced by ford et al. in a graph network under the dynamic setting, each vertex is given supply and each edge is given length and capacity which limits the rate of the flow into the edge per unit time. in this paper, we present a new algorithm for the optimization of the optimal location of a sink in a dynamic network using the minimax regret 1-sink location problem in dynamic path networks as a model. here, we show that the proposed algorithm is efficient for both the maximum regret and the minimum total time evaluation criteria.
we study theoretically the thermomechanical effects which occur in uniformly aligned dye - doped nematic liquid crystals ( nlc ) when the sample is illuminated by a laser beam with a wavelength in the absorption band of the dye, which causes a significant heating of the liquid crystal layer.   this heating leads to an additional torque which acts onto the director together with the light - induced molecular torque. as a consequence of the thermal heating,   the optical fredericksz transition ( oft ) for pure liquid crystals @xcite and the janossy effect for dye -doped liquid crystals@xcite are lower than those for pure nematics. here  , we show that the additional torque might be strong enough to induce the molecular reorientation well before the onset of the light- and temperature - induced thermo - induced reorientations, the so called optical f redericks z transition for pure lc and the Janossy Effect for dyed lc. using a 1d model that assumes homogenous intensity distribution in the plane of the layer ( the plane wave approximation ) and includes the light absorption into the hydrodynamic equations for the nematics, we account for the possible decrease of
the massive thirring model ( mtm ) and sine - gordon model ( sgm ) are important as a testing laboratory for understanding ideas proposed for other more complicated field theories. in this paper   we propose to calculate certain physical quantities for the mtm by performing an explicit diagonalization of its lattice regularization with the @xmath0 spin chain. as the first task we want to calculate the masses of breathers.   the previous calculations have been based on the semiclassical method @xcite, on factorized scattering theory @xaite, or on the bethe ansatz method@xcite. however, these methods rely on the so - called string conjecture which is recently criticized by klassen and melzer ( j. p. melzer, r. w. schwinger, c. t. coleman, e. b. van der waals, f. lindau, d. h. lehane, and a. n. valles ;  ). here we show that the mass of the first breather is exactly what the dashen - hasslacher - neveu ( dhn ) formula predicts.
the traveling salesman problem ( tsp ) is a well - known example of the combinatorial optimization problem, where cities are randomly and uniformly distributed on a line segment.   the random link tsp is a variant of the euclidean tsp, where the individual lengths between cities are taken to be independent random variables, all identically distributed according to some @xmath7. in a previous article @xcite, we have shown that the cavity method can be used to predict the optimum tour length for the randomlink tsp using the distribution of city - to - city distances as a random link approximation to the eucalyptus tsp. here  , we investigate the finite size scaling of the results obtained from the cavity solution, providing evidence that the method is correct. in the process,   our numerics reveal some remarkable properties concerning the frequencies with which cities are connected to their nearest neighbor in optimal tours.. these properties are discussed in terms of the relationship between the random links and the eubjects in the cavity model.
the first disappearance of a magic shell ( n=20 ) and the onset of collectivity far from stability were observed in the n=14, 28 and 50 shell gaps of the one - body harmonic oscillator ( ho ).   these pioneering discoveries opened a new branch of experimental and theoretical researches related to the structure of nuclei far away from stability. in the present contribution  , the striking analogy between the behavior of the ho shell gaps n=8, 20 and 40 from the valley of stability to more neutron - rich regions will be presented. using two recent experimental studies on the @xmath7si and@xmath8 mg isotones, it is proposed that a hierarchy in the nuclear forces is responsible for these drastic shell evolutions.. a generalization of the hierarchy of nuclear forces mechanism to other regions of the chart of nuclides ( around @x Math10ca, below @x math11ni and below @Xmath12sn where the r - process nucleosynthesis occurs ) is proposed.
as a student, i could not imagine how rapidly our ability to map the universe would change over the last twenty years.   wide - field multi - object spectrographs have revolutionized our understanding of the distribution of galaxies in the universe and their relationship to the cosmic microwave background. here   i discuss two projects that have changed the field : ( 1 ) the hectospec redshift surveys of the infall regions of clusters of galaxies and ( 2 ) the new hectomap project, a redshift survey of the sky with a median depth of @xmath3.1 million galaxies.
we study a scalar - tensor - vector theory of gravity which has been introduced as an alternative to particle dark matter @xcite.   this theory is referred to as mog ( modified gravity ) in the current literature. here  , we study the cosmological behavior of this theory by looking for exact solutions for the modified friedmann equations. using the noether symmetry approach, we find that there are some cosmologically exact solutions in mog which correspond to some specific solutions presented in @xmath0/xmath1 and @x math2/x Math3.1, respectively. among these exact solutions,   the one with the largest number of scalar fields is found to be the most consistent with the observed data for the milky way rotation curve data for mond-@xcite, while the other two with the smallest number of non - minimal scalar field are the most concordant with the observations for the heliocentric rotations of the galaxy clusters.
stick  slip motion is a common form of intermittent motion observed in soft adhesive surfaces, which is characterized by repeating cycles of stationary ( stick ) and moving ( slip ) phases at the interface.   the mechanism of stick  slip is known to result from the propagation of schallamach waves, which propagate at speeds much slower than those of elastic waves. however, recent work has suggested that slow waves may also be possible, over and above schall amorphous waves.. the present work seeks to investigate this question by building on observations of single stick  Slip events in a unique adhesive contact geometry. using friction force traces and high - speed   high - in situ _ imaging, it is shown that stick  slide motions are of three different types : ( 1 ) stick  slips are caused by either schallamerach waves or one of two new slow frictional waves  caled separation pulses and slip pulses ; ( 2 ) sliding is initiated by a single wave that propagates at a rate of 0.5  cm / s between the two solids ; ( 3 ) sliding occurs only when the friction force is applied at a constant velocity and is not affected by adhesion ; and ( 4 )
a new way to make waves is described.   it is based on the generalization of the method of characteristics for the cauchy problem to any symmetric hyperbolic system of first differential order equations in a multi - dimensional space with many evolution variables and with source terms for the creation of waves  . the approach is applied to simulate the production of gravitational waves by using a computer to solve einstein s equations.
we present numerical simulations of supersonic, super - alfvnic turbulence, driven on large scales by a solenoidal external force with the sonic mach number @xmath11 of the order 10 and the alfVnic mach number@xmath12 of the Order 3.   the results show that the observed features agree well with the recently proposed kolmogorov  burgers theory of su personic interstellar turbulence. in particular, the velocity - difference structure functions are constructed, and their applicability to molecular clouds is discussed.
spin evolution in quantum plasmasmas leads to existence of new waves.   difference of population of spin - up and spin - down quantum states in equilibrium plasma, which can be accounted by corresponding equation of state, also gives contribution in dispersion of plasma waves.in this paper we present further application of separated spin evolution quantum hydrodynamic ( qhd ) ( sse - qhd).we consider spin-1/2 particles as two different species and derive a new qhd equation for the separate evolution of spin--up and spin--down electrons from the pauli equation @xcite. at consideration of separation of spin-Up and spin-Down electrons,   the second wave solution at oblique propagation of the longitudinal waves in plas masmas reveals existence of novel oblique propagating waves at different population of Spin- Up and Spin-Down quantum states.the new waves were obtained at consideration with respect to wave propagation parallel and perpendicular to an external magnetic field.
the new imaging atmospheric cherenkov telescope ( iact ) h.e.s.s.   ( high energy stereoscopic system ) is located in namibia and is sensitive in the hundreds of gev regime @xcite, a new, unidentified tev @xmath9-ray source that was discovered in the pointings at the be / x - ray pulsar psr b1259@xmath063@xcite for 39 hr of total exposure from 2004 february to june. here   we report on the initial efforts to identify this source using the hegra ct system. despite extensive multiwavelength searches,   the nature of the source remains uncertain.    the source is likely to be in the galactic plane at @x Math10 = ( @x maths11, @x math12 ), and has an intrinsic gaussian emission with an intrinsic optical depth of ~1.0  mag, which is similar to that of the first unidentified source at tev j2032 + 4130, which lies in the direction of the cygnus ob2 stellar association.
the cuore ( _ cryogenic underground observatory for rare events  ) and cuoricino (  cryogenic detector for the detection of non - baryonic particle dark matter  ) experiments are currently undergoing a wide r&d program in the framework of the milano double beta decay ( midbd ) project.   the main objectives of these experiments are to detect neutrinoless double beta decays of @xmath1te and axions, and to investigate the possibility of detecting non -baryonic particles of low energy at the low energy frontier of particle physics, which would be important evidences of a new physics beyond the standard model of quantum physics.. the experimental prospects of both experiments are discussed in the present work.    the results of the midbd experiment show that the use of radiopure detector components and shieldings, the instrumentation of mechanisms of background identification, the operation in an ultra - low background environment, and the state - of - the - art of low background techniques are mandatory for the discovery of such rare events.
we develop a new set of statistical signal - processing techniques for the detection of deterministic and stochastic gravitational waves.   these techniques are robust, meaning that they will work well even if the detector noise is not gaussian but falls into a broader statistical class that we expect includes realistic detectors. in large part, these new methods are similar to the older ones : one constructs matched filters to search for known waveforms or cross - correlates the instrument outputs at the different detector sites to find a sto chastic background. by using locally optimal methods @xcite these statistical measures are modified.the effect is to truncate the statistics : detector samples that fall outside the central gaussian - like part of the sample distribution ( i.e., the outliers ) are excluded from ( or saturated when constructing ) the measurement statistic. for both cases,   a robust statistic is found which performs better than the optimal linear filter in the case where the detector Noise is non - gaussian, and almost as well in the gaussian- and non - stationary - noise cases.
the serendipitous extragalactic x - ray source identification ( sexsi ) program is a fixed observing campaign of the _ chandra X - ray observatory.   the goal of the survey is to identify and characterize the redshift distributions and nature of hard x - rays in the intermediate flux range from which the bulk of the x -ray background arises. with data from 27 archival fields, sexsi is designed to focus on a large - area ( @xmath6 deg@xmath1 ) sample of sources in the mid - depth flux range. here  , we present optical imaging of the sexsi  chandra  fields using the palomar 60-inch ( p60 ) and 200-inch(p200 ) telescopes, the mdm 2.4-meter ( mdm-2.4 ) and 1.3-meter-(mdm-1.3)telescope telescopes, and the keck  i telescope. for each field,   we have identified over one thousand sources, including many objects that are beyond the luminosity range of active galactic nuclei ( agn ). at the same time, we have also generated a catalog of ~1,
the study of antiprotonic atoms and low energy scattering serves a triple purpose : to check some properties of the nucleon interactions, to learn about the structure of the nuclear surface and to find some exotic phenomena as @xmath0 - nucleus quasi - bound states.   the recent cern experiment @xcite has provided new insights into the nature of these phenomena. in this paper   we discuss the advantages of using an averaged effective complex length (  ) to parameterize the data obtained from the x - ray cascade and the annihilation - product studies for the isotropic deuterium / protons pair @x Math1/deuterium at low energies. by taking advantage of the high orbital quantum numbers of the annihilating proton or neutron, the radiochemical method allows to find " cold " nuclei of only one nucleon lost in the annihilation of the nucleus, while the atomic level shifts and widths can be used to detect the products of the annihilation by the nucleus. on the other hand, the recently developed cern experiments allow to find the capture states and final - state interactions of the remaining nuclei after the annihilation process.
we report the results of a new survey of the kinetic temperature of gas transitions in the nh@xmath0 ( 1,1 ) and ( 2,2 ) lines and their hyperfine structure, the 36.1 ghz ch@x math1oh maser line, and the 4.5 ghz hc@x Math1n transitions.   the observations were made using the new widar correlator in the hybrid dnc array of the karl g. jansky very large array ( vla ). from the 18 pointings in 6 clouds ( sgr b2 m&n, m0.25 + 0.01, m-0.11 - 0.08, m+0.02 - 0.,07, the cnd, and m=0.13 - 0..08 ), we measure a median temperature of @xmath2100 k above the ground state for all transitions with energies from 20 to 840 k. the data are used to map the thermodynamics of the transitions, and to estimate the rate of star formation at the level of the galactic center.
many - body approaches such as gw@xcite and the bethe - salpeter equation ( bse)@excite are frequently and successfully employed in the calculation of the electronic structure and excitations of materials.   however, these many - body methods can become cumbersome and impractical for large systems due to the steep scaling of the numerical cost versus the system size.. we propose a minimal time - dependent density - functional theory ( tddft ) model for excitons using two simple kronig - penney - type bands as input which is one - dimensional ( 1d ) and uses two simple exchange - correlation ( xc ) functionals : @xmath0 and @x math0.    we show that the minimal model reproduces and reveals many aspects of excitonic effects, including the importance of the band gap and the use of a coupling matrix featuring @x Math0. while the model is accessible and relatively easy to implement, it can be used to identify important aspects of the local and semilocal xc functional for exciton binding in tddfts.
we propose a time division duplex ( tdd ) amplify - and - forward ( af ) large scale multiple input multiple output ( ls - mimo ) relaying scheme for secure wireless power transfer ( wipt ).   the relay at the power source needs to harvest enough energy from the source for information transmission, and the relay also needs to charge the battery to maintain the active state. in this paper, we derive an explicit expression of the secrecy outage capacity for such a secure wipt system by analyzing the transmission power, channel state information ( csi ) accuracy and transfer distance under imperfect csi. using the obtained results, we propose a power splitting scheme at the relay, so as to maximize the secrecyoutage capacity. moreover, we present some simulation results to validate the effectiveness of the proposed scheme.
the dynamic polarizability of the low - lying ca@xmath3 ion @xcite is investigated using a fully relativistic version of a semi - empirical fixed core potential that has been successfully applied to the description of many one and two electron atoms.   the results show that the magic wavelengths for the ground state of the ca@Xmath3(@x Math0 ) state are the same as those for the @xmath13 and @x maths14 transitions, but the transition matrix elements connecting these states are more sensitive to the magic wavelength than the single - electron dirac hamiltonian calculations. in the present work, the effect of the orbitals of the valence electrons on the dynamics of the outermost core electrons of the cesium microwave clock ( @xaite ) is also investigated.
the study of the formation and evolution of protoplanetary disks is an important topic for understanding the formation of extrasolar planets and the planets in our solar system.   the wealth of information about disk physical structure and chemical composition can only be acquired with multi - molecule, multi - line interferometric observations at ( sub- ) millimeter wavelengths and at sub - arcsecond resolution. to extract all the relevant information from molecular lines and thermal dust continuum one has to cope with the inverse ( line ) radiative transfer ( lrt ) problem, which can hardly be solved for complex geometrical configurations. here   we investigate the applicability of approximate methods for the lrt modeling of prot planetetary disks by using the lvg ( large velocity gradients ) approach. as a result  , we find that the proposed lvg method is able to reproduce the observed data better than the lte ( local thermodynamical equilibrium ) and lvg(large velocity gradient ) approaches, and it is more accurate than the monte carlo or escape probability methods used for the modeling of the kinematics and chemical structure of prestellar cores.
the existence of nonbaryonic dark matter in modern cosmology is strongly supported by several independent signatures, including the cosmic microwave background ( cmb ), gravitational lensing and large scale structure surveys.   however, the nature of dark matter remains a mystery. to reproduce the correct relic density, it is naturally assumed that dark matter is composed of weakly interacting massive particles ( wimps ) such as the supersymmetric neutralino which is one of the most popular candidates. since the self - annihilation rate is proportional to the dark matter number density squared, potential signals from dark matter annihilation are most likely to be detected in highly dense regions such as centers of galaxies. with the high precision cmb data from the wmap satellite  , strong constraints on the properties of darkmatter can be obtained.. here we use a universal model - independent method to place constraints on any dark matter model by convolving the response functions of signal - to - background with a specific injection energy spectrum of electrons and positrons. using this method,   we show that the gamma - ray background anisotropies induced by both annihilating extragalactic dark matter halos as well as galactic subhalos are different from those
we study the effect of beam asymmetry in full - sky cosmic microwave background ( cmb ) single - dish as well as interferometry experiments.   we derive the full -sky convolution for a complex asymmetric beam and define the measured temperature and polarization anisotropies globally on the group manifold of the three - dimensional rotation by using wigner d - functions. to achieve this, we extend the standard anisotropy and polarization correlation functions of domain over the celestial sphere to those over the rotation group manifold. from the results  , we can calculate the full- and partial - sky correlation functions for two typical cases : an elliptical gaussian beam and an interferometric gaussian beams. with the latter case,   the difference between the measured values of the temperature and polarities is of few @xmath6 in planck configuration and increases with the beamwidth and ellipticity.. the former is a good approximation to the actual shape of the window in most of cmb single - Dish experiments and the latter is maximally asymmetric due to the finite length of the baseline of the interferometer. both cases are used to obtain closed forms for the covariance matrices in both
correlation and interference distinguish quantum from classical mechanics.   the former is manifest in the measurement of many - body coincidences predicted by a quantum joint probability density function ( pdf ), which are not observed classically @xcite. to extend this boundary to larger masses, we model correlation of a mesoscopic / macroscopic ` mirror'with a non - zero rest mass microscopic'particle'after elastic reflection. using a two - body quantum analogy, we show that the magnitude of the correlation between the particle and the mirror is proportional to the coherence length of the state of the particle as well as the time of overlap between the two states for both the incident and reflected states.. the results are consistent with the expected results of a one - body treatment for a pulse of light reflecting from a moving thin film but only as a special case.
unstable eigenoscillations, or  unstable modes _, of the stellar disc arising due to self - gravity are characterized by their shape and complex frequency.   if an unstable mode exists, a spiral pattern is formed spontaneously due to the growth of small fluctuations in the initially axisymmetric equilibrium distribution of the stars and the gravitational potential. generally, there can be several unstable modes, and then the form of the spiral patterns is determined by the most unstable mode or a superposition of several modes in the case of close growth rates. here  , we consider available methods for finding disc unstable modes.
we report on the result of a recently upgraded experiment at the spring-8 angstrom compact free - electron laser ( sacla ) with an optimized setup. in this experiment  , we replaced the x - ray beam collider with one with thinner blades.   this yields a higher diffraction efficiency and smaller sizes of the colliding beams ; the beam quality from sacla has also been improved, with respect to the repetition rate, bandwidth and pulse intensity.
we study the behavior of the discrete beta function ( dbf ) of a su(3 ) gauge theory with @xmath9 wilson fermions in the sextet representation.   we find that the dbf of the theory crosses zero at the very large coupling@xmath12, far short of the perturbative prediction for the massless limit of the model @xcite. to test the significance of this finding, we have also calculated observables connected with the potential and with chiral symmetry.
in the present paper, we calculate the total cross sections of pair creation by a coulomb and a strong laser field in the standing wave formed by two counterpropagating laser beams.   the process is studied in the context of the x - ray free - electron laser ( xfel ) facilities being developed at desy ( hamburg, germany ) and slac ( stanford, usa ), which will provide spatially coherent and highly brilliant beams of synchrotron radiation with single - photon energies of up to @xmath13 kev at maximum field strengths of @xcite. when combined with a moderately relativistic ion beam, the laser photon energy in the projectile frame can reach the electron s rest energy. in this situation,   nonlinear electron - positron pair creation in the collision of an ultrarelativistic electron beam and an intense optical laser pulse was observed at slac@xcite using a light projectile beam. here  , we investigate the role of the indirect production mechanism in the formation of the pair by a virtual photon generated by backscattering of the laser photons from the coulomomb field of the electron into the proton
action spectroscopy of the single molecule junction was applied for the single molecular junctions with h@xmath0, o@x Math7, and co @xcite.   the atomic configuration of the au atomic contact in these two environments was investigated by the conductance measurement using the mechanically controllable break junction ( mcbj ) technique. to investigate the effect of the zero point motion on the atomic scale single molecular junction, the action spectroscopic measurements have been performed for the atomized au atomic contacts in h@Xmath0 and d@x math0 environment.    the results show that the atomic motion of the individual atoms of the hydrogen atom is affected by the zeta potential of the metal electrodes. at the same time, the electron current through the single molecules can be measured as a function of the bias voltage. here   it should be noticed that hydrogen has large zero point energy due to its small mass.
the development of large - scale fabrication methods for structured surfaces with feature sizes in the nanometer range is still a constant challenge in thenanotechnology community.   an accurate control of the surface topography would have a great impact in the fields of materials science and nanotechnology. in this report   we show that by ion irradiation technique it is possible to tune the surface morphology on the nanometric scale that is in conformity with the strategy of using irradiation techniques for producing large - size nanopatterned surfaces.    the method we propose and demonstrate involves the self - assembly of metal nanoparticles on si substrates by vacuum deposition of thermally evaporated metal atoms followed by low energy ion beam irradiation. when the ions impinge on the empty surface ( i.e. between the interisland space ) they amorphize si upto a depth comparable to the ion range in si. as a result   the thickness of amorphous si under the metal islands is smaller, and the near - surface region of the substrate develops a pattern which can be transferred to produce nanoscale islands of @xmath0. at room temperature   only a few nanometers are required to achieve confinement effects at
the jagiellonian - pet ( j - pet ) collaboration is working on the construction of a whole body positron emission tomography ( pet ) scanner based on plastic scintillators.   the detector will be built out from strips of plastic scints arranged in a diagnostic chamber and will be able to detect low energy gamma quanta with very good time, position and energy resolution for the registration of low energy quanta. in this paper   we present experimental results for the determination of the energy, time and position resolution of a single detector module of the j-pet detector using a prototype module consisting of a bc-420  @xcite scintilator strip read out by photomultipliers at both ends. due to the negligible probability of photo - electric effect,   it is possible to obtain an energy resolution of up to 1.5  ps  ( fhwm ) for the detection of annihilation quanta in the range of fraction of mev which is comparable to that of commercial commercial pet scanners.
galaxy clusters are the largest bound objects in the universe.   they provide information on gravitational instability, and understanding their formation is helpful in describing the transition to nonlinearity in structure formation. when projected galaxy clusters were fit to ellipses by a variety of procedures, their eccentricities were found to evolve on a timescale comparable to one or two crossing times for the clusters. here   we explore the evolution of eccentricity in a series of cosmological simulations based on cold dark matter and gaussian perturbations ( cdm ) using x - ray data from the @xmath3cdmh simulation, which includes hydrodynamics. with the initial conditions used, we find that the cluster eccentricity evolves on a time scale similar to that of the observed galaxy clusters over the redshift range 0 to 0.13. at lower redshifts,   the eccentricity of the clusters becomes less eccentric, but this is not statistically significant. at higher redshifting, the distributions of the eccentricities are more irregular, and the distribution of the axial ratios is most similar to those of observed clusters. while there is some evidence for evolution in the data, the effects of the background cosmology
temperature profiles of galaxy clusters are of great importance for two main reasons : firstly they allow us to measure the total mass of these systems through the hydrostatic equilibrium equation and secondly they provide informations on the thermodynamic state of the intra cluster medium ( hereafter icm ).   measurements of temperature profiles have been performed with the first generation of x - ray satellites carrying telescopes operating in the medium energy band ( 2 - 10 kev ) ( asca and bepposax ). in this note   we derive the mean temperature profile for a sample of hot, medium distant clusters whose profiles are available from the literature and compare it with our mean beppo - newton profile.
we report theoretical and experimental studies of diffusion of optically injected spin - polarized carriers in an intrinsic semiconductor without an externally applied electric field.   the carrier system is composed of spin - up electrons, spin - down electrons, and holes, which are excited in gaas quantum wells by a tightly focused and circularly polarized laser pulse. since holes are unpolarized, they influence the diffusion ofspin - polarized electrons via the coulomb attraction. to study the effect of the holes on the diffusion process, we have used the spin - grating technique to investigate the transport of electron - hole pairs in aqueous solutions of an intrinsic nanocrystalline gaas semiconductor with an external electric field ( @xmath1 = 0.5  nm ). using a linearly polarized probe pulse, we show that the diffusion rate of spin- and hole - polarization - injected spins is strongly influenced by the presence of holes, and is driven by the density gradient of the excited carrier density at the excitation spot.    the diffusion rates of spin--polarized and spin- or hole - unpolarization - injected electrons are determined by measuring the differential transmission of the polarization state of the pump pulse across
parse signal recovery problem is the reconstruction of sparse signals with characteristic of " sparsity " from a set of nonadaptive linear measurements.   it has great potential of application on various engineering fields such as coding and information theory, signal processing, machine learning and others. in this paper, we present a new greedy algorithm for sparse signal recovery based on convex optimization. to achieve optimal results,   the method is based on iterating by solving the inner products of residue vector @xmath13 with the columns of measurement matrix@xmath1 and then solving least squares problem to obtain the estimation of original signal on each iteration.. the convergence of the estimator to original signal is ensured by using restricted isometry property ( rip ) on measurement matrix @x Math1 to guarantee the equivalence of (  and (  ) which are commonly used in previous algorithms.
we investigate the possibility of a delocalization of self - trapped composite entities, given by bosonic charge carriers strongly coupled to local bosonic excitations of the environment, into a macroscopic coherent quantum state.   we show that this can be achieved by blocking the dephasing of the interaction between the charge carriers and the bosonic effects of the surrounding medium. in the intermediate coupling limit   these localized entities can be considered as two - particle resonant states of the underlying system of itinerant electrons.
graphene - based superlattices have attracted a lot of research interest due to their remarkable electronic properties and their potential applications in nanoelectronics.   however, the electronic properties of the gapped graphene - based devices are not well understood. in this paper, we investigate the electronic band structures and their transport properties for the grapped graphene superlattenuated with one - dimensional ( 1d ) periodic potentials of the electrostatic potentials generated by different methods, such as the quantum confinement effect in graphene nanoribbons and the quantum hall effect for the low - energy charge carriers group velocities @xcite, and the formation of the extra dirac points and new zero energy states inside the gapless graphene super lattices. using the Dirac equation, we have found that a new dirac point is formed at the energy which corresponds to the zero averaged wave - number inside the two carbon sublattice of the graphene grown on sic or boron nitride substrate, and it is very important to generate a gap of at least 450mev around the fermi level near the dirac fermion@xcite in order to control the electronic conductivity of
the dual - beam imaging polarimeter ( dbip ) for the uh 88-inch telescope is a new instrument for polarimetric imaging of asteroids.   it is capable of simultaneously measuring both orthogonal polarization states for point sources to an accuracy of better than @xmath5, and is designed to be independent of flat field effects as well as changes in seeing or extinction. by using a double - calcite savart plate and a half - wave plate,   the polarization values determined are independent of both flat field and temporal variations. when used correctly, the measurements can be performed with a precision of up to 0.2% over a wide range of observing nights.
the existence of a pseudogap in the density of states of the electrons in the metallic layers of the cuprate high temperature superconductors in the underdoped regime is one of the key elements to guide us in unravelling the underlying mechanism for superconductivity in these materials.   the most immediate temptation to explain the opening of such a pseudo gap is to consider it as a consequence of superconducting phase fluctuations corresponding to a finite and relatively long lived amplitude of the order parameter above @xmath0, but recent experiments on the specific heat are in support of this scenario.. the purpose of this communication is to elucidate the nature of the pseudogaps as given in the scenario of the boson - fermion model.    the role of the precursor effect in low dimensional systems is discussed.,1 the effects of antiferromagnetic spin fluctuations on the formation of a two particle resonant state triggered by the existence of extrinsic ( in contrast to intrinsic in single component systems ) bosonic modes such as localized polarons or bi - polarons are discussed.
the statistical temperature of a fluid flow is calculated as a function of the reynolds number.   the temperature is found to be positive at low reynold numbers, associated with laminar motion, and negative at high reynthesized numbers, which are associated with turbulent motion. in this paper  , we show that the temperature changes from positive to negative as the structure size exceeds some critical value, similar to what was discovered by onsager for the microcanonical ensemble of parallel point - vortices in an inviscid fluid confined to a finite region of physical space.. the temperature exhibits a power - law divergence characteristic of second - order phase transitions in the range of intermediateReynolds numbers.
the sparcsgillianw / sparcs survey ( @xcite ) is the largest, homogeneously selected cluster candidate detection project in the history of the space telescope community.   we have previously reported spectroscopic confirmation of three clusters of galaxies at @xmath17,@xmath18 and @x Math19 using the spitzer wide - area infrared extragalactic survey ( swire ) legacy survey ( ~41.9 deg@xMath16 ). in this paper  , we report spectroscopy confirmations of three additional clusters at @Xmath19 and @ xmath20 using the same approach.    the results show that the observed clusters are highly similar in size to those detected by the existing x - ray surveys ( rdcs j0910 + 5422, rdrs j1252.9 - 2927, rx j0848 + 4452, xmmu j2235 - 25, and xmmxcs j2215. 9 - 1738 ), and that the radial velocity dispersions and dynamical masses of the clusters are not significantly different from those observed by the x - rays.
the entropic stabilization mechanism, described above, has been used in several theoretical models to quantitatively describe the extent of folded protein as a function of the volume fraction, @xmath13, of the crowding agents @xcite.   we investigated the effect of crowding on the mechanical stability of ubiquitin ( ub ), a 76-residue protein composed of 5@xmath29-strands and 2 @x Math30-helices. using atomic force microscopy ( afm ) and laser optical tweezers, we measured the force - extension curve ( fec ) of the protein under tension at various concentrations of @xcide.. the results show that the fec increases by a factor of @x math13 with increasing the concentration of crowded particles. from these results, we propose that the entropy of the denatured state ensemble ( dse ) decreases relative to its value in the bulk, and that crowding enhances the stability of the dse.
we have recently completed the analysis of the data from a ground - based imaging survey of the globular clusters ( gcs ) of eight spiral, elliptical, and s0 galaxies.   we show that the metal - poor milky way gcs are some of the first structures to form in the universe and that they were formed during a period of intense star formation at the earliest stages of the galaxy s history. by comparing the spatial and metallicity distributions of the early and late - type gc systems of the galaxies, we can test the predictions of models for the origins of elliptical galaxies.
the bcs theory of superconductivity has been generalised to multiband systems with isotropic ( spherical ) fermi surfaces. in this paper   we adopt the microscopic approach of gorkov generally for uniform multibond systems with anisotropic d - wave gaps, where the energy gap is equal to the order parameter of the ginzburg and landau ( gl ) theory for single band superconductors.   these systems are characterized by two or more energy bands cut by the ferm i energy giving rise to multiple energy gaps with different magnitudes in the different fermani sheets.. the equivalence of the bcs energy gap with the order parameters of the gl theory for one- and two - band systems is investigated using a combination of tunnelling, point - contact spectroscopy, angle - resolved photoemission and specific heat measurements.    the effect of the josephson term on the order parametrization of the energy gaps is also investigated.
we investigate the time - evolution of gaussian wavepackets in graphene under external magnetic fields using a split - operator technique for the expansion of the time- and energy - evolution operator.   the results show that for an appropriate choice of external and strain - induced magnetic fields, the system exhibits a strong effective magnetic field for particles in one of the dirac cones, whereas in the other cone the external and pseudo - magnetic fields cancel each other and the effective magneticfield is practically zero. this effect is manifested as a transient ( permanent ) zitterbewegung for electrons in the cone where the external magnetic field is zero ( non - zero ), which can be verified experimentally by detecting the electric field radiation emitted by the trembling wave packet.. moreover, our results demonstrate that with such a choice of outside and strains, one can construct an efficient valley - type valley - gap in the graphene energy spectrum.
the stabilization conjecture is that any pair of heegaard splittings requires at most one stabilization to be equivalent.   the purpose of this paper is to produce several families of counter - examples to the stabilization conjecture. here   we present three families of these counter - example, which are constructed by gluing two handlebodies together by a very complicated homeomorphism and have very high hempel distance. in the sequel @xcite we use the machinery presented in the previous work to show that sufficiently complicated amalgamations of unstabilization, boundary - unstabilized heegaards can be used to obtain higher genus splitting of higher genus.
the @xmath0 is a resonant state with strangeness number @x Math3, and @x math4.   it has been shown to interact strongly with nearby meson - baryon states, the details of which are intimately dependent on its internal structure. in this work   we have used a simple hamiltonian effective field theory model to identify the @x maths0 in the finite volume of the lattice using the flavour singlet couplings of the three - quark operators @xcite to the bare basis state required by the admission of a three-quark configuration carrying the quantum numbers of the @Xmath0.. the results show that the @ xmath0 does not interact with any of the two - particle channels described in the literature, but is instead dominated by a molecular @xMath5 bound state at light quark masses @xcites.    the low - lying excitations observed in the experimental data are explained by the use of octet - flavour interpolating fields associated with the lattICE correlation matrix.
the nn effective interaction is renormalized using the lee - suzuki method in order to be able to use small model spaces.   this method is based on the expansion of the nuclear wave function as a sum of a large number ( as many as the accuracy demands ) of symmetry unrestricted slater determinants ( sd ) with the appropriate angular momentum and parity quantum numbers restored with projectors, the slatereterminants being determined solely by variational requirements. here   we show that the method is applicable to nuclei in the @xmath4 region using phenomenological effective interactions, which are relatively easy since the bulk of the energies are obtained from the local potentials of the nuclei under study, and it is possible to determine the exact ground state wave function of the nn potential for both closed and open shell nuclei without the use of the bare interaction.
the abundance patterns of light neutron - capture elements in the near - uv region of the spectrum of the extremely metal - poor star cs  22892052 (  @xmath1 z = 48 ) have been studied with the 8.2  m subaru telescope.   the abundances of pd and ag, which exist between the first and second abundance peaks produced by the rapid neutron capture process ( r - processes ), are found to be significantly higher in the star than in the solar system r -process component ( /fe = 0.7    0.5  fe / h ). for all the elements studied, the relative abundance patterns from the 2nd to the 3rd peak are identical, within observational errors, to that of the ( inferred ) solar system R - process component. here  , we show that the abundance pattern of the heavy neutron - Capture elements ( ba, sr, and pd ) in this star is very different from that observed in solar system material, and that the distributions of these elements vary with the abundance of the weak r - Process.    the results are consistent with the existence of another r
we study the thermodynamics of a confined system of spin - polarized fermions in the presence of a magnetic field.   the method used is an extension of the combination of the path integral formalism @xcite and the method of symmetrized density matrices, developed previously for a model system of harmonically interacting identical particles in a parabolic well ( hereafter referred to as the harmonic model ) with a two - body potential. using this model, we show that the ground state energy and the magnetic susceptibility in the zero - temperature limit are similar to those obtained with no magnetic field in the case of bosons in the present paper. however, the free energy of the center of mass excitations is significantly reduced below the condensation temperature for a finite number of particles, and its moment of inertia is drastically reduced below this temperature. also the magnetization susceptibility of the system is considerably reduced under the same conditions.
we report on the detection of strong h@xmath0 emission in sori55 ( sorij053725.9023432 ), which was previously identified as a cool, very low mass substellar member of the young @xmath2orionis open cluster.   we measured an m9 spectral class with an uncertainty of half a subclass, in full agreement with the previous assignement of barrado y navascus et al@x math6 @xcite and with the observed @x Math11 colors.    interestingly, sori 55 displays typical low - gravity features, such as the absence of the star s outer envelope and the presence of a disk around it.
the origin of thermodynamics is still under dispute.   it is, however, an empirical fact that macroscopic systems behave according to the laws of thermodynamic and are routinely viewed as large quantum systems. in this paper   we discuss a quantum model corresponding to the archetypical thermodynamic scenario in which two ( equal or similar ) microscopic bodies are prepared at different temperatures ( possibly a hot and a cold coffee mug ) and then brought into contact but kept isolated from any environment.. experimental evidence shows that the dynamics of the temperature difference ( here called @xmath0 ) is autonomous and markovian in the sense that it may be described as@xmath1 where @x Math2 denotes the rate of change.,we numerically analyze the same model class in the paper at hand but for larger systems and a much wider range of initial states. using the fokker - planck model suggested in @xcite, we essentially find that, while indeed autonomous Markovian, deterministic @x math0-dynamics emerges in general, specific predictions of the fakie - korsmeyer model suggest that the equilibrium thermalization dynamics of these systems are not irreversible.
coherence is a basis - dependent quantity in quantum physics.   it is the premise of quantum correlations in multipartite systems, and its quantification has attracted the attention of quantum information community significantly. in this paper, we revisit the complementarity between coherence and mixedness of a quantum state, and the distribution of coherence in multi- and single - quantum systems in considerable detail. to address this issue, we review the axiomatic approach to characterize and quantify coherence as a new quantum resource, and provide several analytical and numerical results in this regard. in particular, we show that the reciprocity between co coherent and mixededness in quantum systems is an extensive feature, and that the degree of reciprocity is proportional to the number of quantum states in the mixedness set. also, we demonstrate that the coherence transformations under incoherent operations can be used to create coherence using local and nonlocal unitary operations.
numerical studies of the einstein equations are often prone to various instabilities, which we divide into three classes : ( 1 ) continuum instabilities ; ( 2 ) numerical instabilities and ( 3 ) artificial long - term " instabilities " ( alti ). in this paper   we focus on these instabilities together with the application of the techniques described in  @xcite, which throughout this work we refer to as paper  i. we evolve klein  gordon scalar fields and maxwell fields on fixed schwarzschild spacetimes, obtained via coordinate transformations of flat spacetime, and show that we naturally obtain stable and convergent numerical schemes by construction, even when an inner boundary is used to remove the black hole singularity ( black hole excision ).   a second goal of this paper is to understand some causes of long - time error growth ( altis ), which are sometimes exhibited even by numerically stable implementations, whenever errors grow too fast for the desired simulation time - scale and available computational resources.
millisecond pulsars ( msps ) are a major population of gamma - ray emitting pulsars discovered with the large area telescope ( lat ) onboard   fermi.   they are of particular interest because they represent an important stage for the evolution of compact stars. in this letter, we report a multi - wavelength identification of a " radio - dim " gamma - rays emitting msp candidate that could be associated with an ultracompact x - ray binary. to identify suitable targets for investigation, we first selected candidates from the unidentified source catalog based on three criteria : 1 ) source variability ; 2 ) high galactic latitude ; and 3 ) gamma-ray spectral shape. using the variability index in the second lat pulsar catalog, we found that the source is a black widow or redback pulsar with a diameter of ~1.5 cm and a mean velocity of ~2.0 km / s. as a result, we propose that the pulsar is likely to be a member of a binary system with a compact star mass.
the sun is covered in a pattern of small magnetic features that dominate the photospheric magnetic energy budget.   these small - scale magnetic fields are important for the overall magnetic flux and energy budgets of the sun, and are important in structuring and heating the chromosphere and corona. here   we review the current understanding of the origin and role played by these small-scale magnetic fields, and discuss recent observational evidence that supports the existence of a shallow near - surface dynamo on the sun.
we present a study of the evolution of the low accretion rate polars sdssj204827.9 + 005008.9 and sdss121209.31 + 013627.7, which have a low mass transfer rate and a low temperature for their white dwarfs.   these systems are considered to be larps because they have very low levels of accretion luminosity and have been in a low state for long periods of time ( ~2 yr@xmath3 ). while the white dwarf temperature is the main difference between larps and normal polars in low states, the secondary size and the presence of a brown dwarf secondary suggest that the systems are either pre - polars or preps. here   we show that the two systems are not so separate from each other as previously thought, but rather that the effects of low degrees of mass transfer and low temperatures on the accretion rates of the secondaries are different. using time - resolved uv observations, we find that the larp mq dra with an even lower @xmath7 of 10@x Math0 m@x math1 m=10@x maths2 yr/yr@xMath3
the study of the critical properties of lattice polymers in two dimensions has been ongoing over decades theoretically and numerically.   we study by means of monte carlo simulation the semi - flexible vertex - interacting self - avoiding walk ( visaw ) polymer model precisely at the bn - point, which we shall refer to as the'collapsing polymer ', for which the critical exponents are @xmath19 and @x Math20. using transfer matrices and the density matrix renormalisation group method ( dmrg ) we find estimates for the exponents, and hence the scaling dimensions, that are in harmony with those found by foster and pinettes @xcite and at variance with those predicted by warnaar _   et al. in this paper.
in general relativity ( gr ), the orbit of a test non - spinning particle moving at stable circular orbit around a central gravitating body is different from that of a spinless one.   in particular, the orbits of a spinning test particle differ from those of a non-spinning one even in the schwarzschild metric. in this paper   we review the problem of the motion of a classical spinning test body in gr and discuss the influence of spin on its orbit.
particle gels form in suspensions if short - range attractions act between contacting surfaces of particles.   their remarkable and complex mechanical properties under external stress are essentially due to the response of a deformable disordered network formed with all the particles. here  , we investigate the effects of compressive stress on the formation of strongly aggregated particle gels by considering the characteristic structure of the backbone structure of a particle gel based on the fractal model. for a given packing fraction of particles,   the shear modulus of the network is proportional to the average size of the flocs, and the yield stress is the highest stress that can prevent flow when the packing fraction is larger than 2.5. using a combination of experimental and theoretical data, we show that the strength of the deformed network is not constant during the compression process, but is highly nonlinear in the case of a larger packing fraction. as the packing fractions of particles increase, the yield stressed network becomes more compact and the stress is less effective at preventing flow.
the kondo effect is a well - known property of the interaction of a localized spin impurity with the conduction electrons of a metal.   it arises as a result of the coupling between localized and extended electronic states, and thermodynamic properties such as susceptibility and specific heat have been thoroughly studied for many years, both theoretically and experimentally@xcite. in this article   we present an alternative approach to analyze highly non - equilibrium atom - surface systems, namely the dynamical @xmath1 method which takes the repulsive coulomb interaction strength @x math2 between electrons residing on the impurity or scattered atom to be infinite. here   our results are compared with previously published results from the non - crossing approximation ( nca ) method, and the accuracy of the @x Math1 expansion is tested down to the spinless @x maths3 limit. by including a new sector in the wavefunction which describes the amplitude for two particle - hole excitations in the metal,   the accurate calculation of the kondo temperature can be improved.
galactic cosmic rays ( crs ) are believed to be accelerated via first order fermi mechanism at the expanding shock waves of supernova remnants ( snrs ).   two of the strongest points supporting this scenario are : ( i ) the fact that snrs alone are capable of maintaining the galactic cr flux at the observed level, provided that a fraction of about 10% of their explosion energy is somehow converted into crs @xcite, and ( ii ) some shell - type snrs have been detected at tev energies, as expected if they indeed are the sources of crs@xcite. in this context,   the observed tev gamma rays originate from the decay of neutral pions produced in interactions between the accelerated crs and the interstellar gas swept up by the snr shock. however, the detection of snr gamma - ray emission, though encouraging, can not provide by itself the final proof that crs are indeed accelerated at snr shocks. for this reason, the search for evidence of cr proton acceleration coming from gamma ray or multi wavelength observations is mandatory.
the mass distribution of unseen matter in galaxies is well established from the observation of rotation curves ( rcs ) and cosmological simulations.   however, the existence of invisible matter in spirals is still poorly understood. here   we show that the observed circular velocity profile emerging in cosmology must comply with the scaling laws among local and global galaxy quantities, i.e. the baryonic fraction in spiral kinematics is always much smaller than the Cosmological value, and it ranges between @xmath21 to@xmath22, suggesting that processes such as sn explosions must have removed a very large fraction of the original hydrogen. at any radii,   objects with lower luminosities have a larger dark - to - stellar mass ratio, and they are more likely to have a cored halo profile than those with a nfw halo cuspy profile. for this reason, we propose a new model of the structure formation of spirals that includes a freeman disk and a dm halo with a burkert profile, which is consistent with the observed radial tully - fisher relation.
the black hole binary cygnus x-1 ( cyg x-2 ) is a well - studied black hole system with two distinct states : the high / soft state and the low / hard state.   the latter is characterized by an optically thick and geometrically thin accretion disk, which releases most of the gravitational energy in locally thermal equilibrium radiation, and a powerlaw emission with a photon index of @xmath2 of which the origin is commonly considered to be compton scattering by a disk corona with a hybrid ( thermal + non - thermal ) electron distribution ( e.g.,@xcite, tananbaum et al.  1972, @xcite ), along with reflection features arising from disk regions illuminated by the powerlaw component. here   we present a new model of the accretion flow from cyg X-2 in the low/hard state, which is based on a truncated disk / hot inner flow model that accounts for the observation of the observed spectrum correlations between the spectra of the two states. as expected, the shape of the corona is more closely related to the location of the innermost disk radius than the outer one, while the
weak measurements have been shown to be very helpful in several experimental tasks, as well as in revealing fundamental concepts.   we analyze the strength of weak measurements by addressing the question of quantum state discrimination. for the task of discriminating between two non - orthogonal vectors,   the question is what are the best projections to choose so that the error probability would be as small as possible?   there are several known methods for this problem, i.e. for the decision of which vector was chosen out of a predetermined set of ( possibly close ) state - vectors. here, we show that using enough weak measurements ( the number of which is a function of the weak coupling ), the overall success probability converges to the known optimal result for discrimination by projective measurements @xcite. however, if we reduce the numbers of measurements, thus compromising the success probability, we gain an advantage by avoiding the collapse.
we develop a model of the quasi - linear diffusion ( qld ) of particles in the magnetospheres of active galactic nuclei ( agns ) driven by the feedback of the cherenkov - drift modes.   the model is based on the fact that the synchrotron radiation is suppressed for strongly relativistic electrons, but can still be generated in two energy bands because of the feedback between the excited cyclotron waves and the quenching of the diffraction by means of the qld. under certain conditions the dissipative and diffusion factors balance each other, the physical system reaches stationary state and the pitch angles of resonant particles are saturate. as a result, the cyclotromagnetic waves are excited by the x - ray emission from the magnetosphere of agns and the absorption spectra of the emitted particles are correlated in two different energy bands.
the search for the exotic states in the observed hadron spectrum has been a subject of both theoretical and experimental investigations for decades.   the exact pattern, how these states emerge, should be strictly determined by the underlying theory and should therefore contain important information about the behavior of qcd at low energies. in practice, however, extracting such information from the data encounters certain challenges, which are in part of a conceptual nature. in the present paper   we wish to focus exactly on this issue.
recently, several groups have reported their detections of relatively faint x - ray transients in the galactic center region @xcite.   these transients are assumed to be near the galactic centre, based on their absorbing columns and their sky distribution, although no direct distance measurements are available. with this assumption,   the inferred luminosities of the transients can be estimated to be in the 10@xmath010@x Math1 ergss@x math2  range. however, the authors of these studies claim that such a luminosity is too high for cataclysmic variables ( cvs ), semi - detached binaries in which the accreting object is a white dwarf, and argue for neutron star or black hole accretors based solely on the luminosity. here  , we review the current knowledge of the x -ray properties of classical novae and recurrent novae, and discuss the possible origin of the observed galactic center transients.
we propose and theoretically analyse a novel mechanism of actuation of a slender body immersed in a viscous fluid in conditions where inertia is negligible.   we show that a passive elastic filament can be actuated by attaching an active colloid to its terminus. the dynamics of a such an assembly is unexpectedly rich when the flow of the surrounding fluid and the forces it mediates are taken into account. from this  , we identify states of filament motion that are most suited for biomimetic tasks such as propulsion and mixing.
relaying is central to wireless mesh and ad hoc networks, and is a potential enhancement for existing cellular networks.   the forwarding strategy used at the relays and the resulting network capacity are inherently coupled, and it is not obvious which of the above forwarding strategies, if any, is information theoretically optimal for a particular network topology. in this paper, we introduce a new queue - architecture to store the input sequences, which allows us to optimally exploit different states to do amplify - and - forward. under the amplify -and - forward scheme,   each relay observes an input sequence, whose " rate" is dependent on the state it was encoded for, which is not a conventional packet. using this algorithm, we characterize the stability region of the four - node relay network under the amplifying - and-forward scheme, which in general is larger than that under the conventional amplify - &-firing scheme which does not allow signal buffering. by comparing the performance of the throughput - optimal stable cooperative relaying algorithm with that of the current one, we also propose a throughput - optimized algorithm, which achieves the stability regions.
entropy is a key concept in thermodynamics and statistical mechanics.   it is the key concept, upon which the equilibrium statistical mechanics is formulated @xcite, and from which all the other thermodynamical quantities can be derived. here  , we present a new method for the estimation of entropy from data - based probability density estimation of self - gravitating systems, i.e., by bayesian probability theory. to obtain the optimal number of bins in a uniform bin - width histogram, we use kernel estimation method, which is considered to be much superior to the histogram method, in that the entropy increases as a monotonic function of the kernel bandwidth @xmath5. using this method, we find that the system s entropy increases monotonically with the bin width, and thus it is not difficult to select an appropriate bin width of histogram for computing the entropy.
we study how the interplay between thermal effects and boundary conditions, as well as geometry, affect the measured mechanical properties of graphene sheets.   we find that thermal fluctuations in the temperature at which the sheet is covalently bonded lead to a length - scale dependent stiffening of the microscopic bending rigidity of the graphene sheet, which is essential for stabilizing it as a 2d, approximately planar, crystal against the thermal fluctuations that often entropically dominate 2d systems with continuous symmetry.
we derive a simple analytic relation between the width of broad emission lines and the continuum slope of the central engine.   the observed velocity dispersion is determined by the mass of the black hole and the broad line region radius, and the proposed relation is in agreement with reverberation mapping observations.
nuclear resonances and excited states can be very complicated many - body structures with a number of different decay modes.   both the structure of the initial state and the decay mechanism are essential and both must therefore be properly described simultaneously. for two - body decay, like @xmath3-emission, the relative potential determines all properties. for three - body bound states and resonances   " large distance " is less well defined. in the present paper   we establish a general method to compute relative energy distributions after decay into three particles. using the hyperspherical adiabatic expansion method @xcite, we show that the short- and intermediate - distance resonance structure can be computed by use of the same approach but the asymptotic behavior in momentum space is different for the different decay mechanisms. at small distances   the wave function is dominated by the component related to the lowest effective potential. at intermediate distances the potential has a barrier which is decisive for the width of the resonance. at large distances the resonance wave function   is characterized by outgoing waves which contain information about distributions of relative energies and possibly other quantities like spin distributions.
we propose an approximative model for the description of time delayed feedback in the low pumping regime in the system consisting of two emitters inside a cavity subject to feedback.   this model is based on the schrdinger picture, which is applicable in the regime of small pump rates and is easy to implement since it basically involves the numerical evaluation of schndinger s equation with an effective, dissipative hamiltonian. using this model, we show how feedback can be used to amplify bunching and antibunching, as well as to increase the amount of entanglement between two two level systems inside a driven cavity qed system.
inflation is one of the essential ingradients in modern cosmology.   however, it can not be accommodated in a perfect fluid assumption in the framework of einstein general theory of relativity ( gtr ). to accommodate the late accelerating phase of the universe, a modified form of the equation of state for chaplygin gas ( mcg ) with three parameters @xmath12, @x Math13, and @x math14 is considered.. the equations of state are derived from the nambu - goto action for a d - brane moving in a ( d+2-dimensional space - time ) in the light cone parametrization. at a later epoch the fluid behaves as a cosmological constant which can be fitted to a @x maths18cd = 0.5 + 1.0 cosmology constant by using the phase transition mechanism.    the model is then used to study the structure formation and perturbation power spectrum of the expanded universe.
we present a dynamic model based on an intrinsic mechanism with non - markovian feedback, which is obviously free from an external feedback loop and does not rely on a presupposition of historical dependence.   this mechanism is illustrated by a simple mechanical system in which the target is modeled by a harmonic oscillator and attached to a dynamic controller, which controls the motion of the target resonator through a spring. using proper parameter setup,   the target essentially experiences a resistance and decelerates its motion ; its displacement variance is shrunk, noise suppressed and effective temperature cooled down.graphical abstract
the products of killing horizon areas for certain multi - horizon black holes in four and higher dimensions are independent of the black hole mass and depend only on the quantized charges.   this observation is based on the observation that the area of a killing horizon is related to its entropy through the famous bekenstein - hawking formula, which corresponds to a statistical mechanics based on microscopic models counting microstates determined by quantum gravity. when there are outer and inner black hole horizons, the quantization rules recurrent in the literature are integers for supersymmetric extremal black holes but are related to the numbers of branes, antibranes, and strings in less simple situations ( e.g. supergravity and extra - dimensional black holes with angular momentum and electric and magnetic charges were considered ). here   we show that these rules are not universal for all types of black holes endowed with multiple horizons and that it is quadratic combinations of the various horizon radii ( with the dimensions of an area, which can be referred to as " generalized areas " ) which generate mass - independent quantities and are, presumably, the best candidates to be quantized.
we estimate the detection rate of binary lens events expected from a high cadence pixel - lensing survey toward m31 based on detailed simulation of events and application of realistic observational conditions.   we find that the detection efficiency of the survey is dependent on the size of the source star and the number of images taken by the telescope. for an infinitesimally small source element,   the event rate is @xmath7 per season and for a large one, the rate is@xmath8 per season.  in addition, the detection rates are higher for binary events relative to single lens events because many of binary events involve caustic crossings during which the magnification is high and thus more detectable. among the binary events, the highest detection rate is expected from the survey of the magellanic cloud field where the line of sight passes through the halo of our galaxy.
magnetic small - angle neutron scattering ( sans ) is one of the most important techniques for microstructure determination in magnetism and magnetic materials research.   the phenomenological continuum theory of micromagnetics, i.e., the variation of the direction of the local magnetization vector field @xmath4 from its mean value, allows one to compute the magnetic microst structure of a material by analyzing the differential magnetic scattering cross section of ferromagnets with _ uniform _ values of the saturation magnetization and the exchange interaction, but with a highly nonuniform magnetocrystalline and/or magnetoelastic anisotropy. here  , we extend the micromagnetic scattering approach to materials having _ non uniform _ saturation magnetizations.    prominent examples are two - phase hard and soft magnetic nanocomposites, which are used e.g.  in electronics devices, transformers or motors. as a result, the jump in the magnitude of the magnetization at the particle - matrix interface gives rise to a magnetostatic stray field which represents a dominating source of spin disorder. 	 the results of this study are presented in terms of the corresponding spin - spin correlation function
the earth s tidal perturbations on the nodes of lageos and lageo ii and the perigee of  are studied by means of a space - based experiment.   the results are used to assess the level at which the poor knowledge of the earth s solid and, in particular, ocean tides affects the measurement of the combined residuals of the first two even zonal harmonics of the @xmath9 harmonics.
we report the identification of the rass x - ray source rxj0757.0 + 6306 (= 1rxs j075700.5 + 630602 ) as a new cataclysmic variable ( cv ).   the object is a close binary system with a white dwarf primary accreting matter supplied by a late type main - sequence secondary star via an accretion disc or along the magnetic field lines of the white dwarf. in the present study   we observed the object using the 2.1 m telescope operated by inaoe at cananea, sonora, mexico and the boller & chivens spectrograph with a 600 l / mm grating used to obtain spectra in the @xmath7 range with@xmath8 fwhm resolution. during the observation the object was observed alternating between @x Maths 7 and 8 for about 3 h. the orbital periodicity of the system was determined by observing the object over a period of time ranging from ~3 to ~6 h. this periodicity is consistent with the existence of a second periodicity due to the asynchronously rotating white dwarf and a beat period between orbital and spin periods.
we present the simulation results for the beam position monitor ( bpm ) and for the small assembly which incorporates a circular ceramic insertion with circular bellows and rf - shields of elliptical cross sections.   both analytical formulas and simulation codes were used for this purpose. in transient simulations ( cst microwave studio - cst mws )   the faces of the model which correspond to beam - pipe cross sections were considered as waveguide ports, and simulated assembly was excited by a current pulse passing trough a thin wire placed on the beam axis. at the cut - off frequency of @xmath13 the bpm impedance is found to be significantly higher than the longitudinal impedance of the nestor ring which is under construction in nsc kipt @xcite. in wakefield simulations wakes were calculated for the long - ranged wake function of the beam positions monitor ( pick - up ) with a charge using cst particle studio suite 2010@xcite ; the results are presented in terms of loss factor.
we study population iii star formation in a single cosmological realization varying the strength of the lyman - werner ( lw ) background, with the goal of investigating the effect that this background has on the evolution and properties of gas in the halo core ( at radii @xmath18  pc ) and the ultimate fate of the gas at the center of t@xmath5  k halos.   we find that the formation of primordial stars is delayed in the presence of a strong lw background, and that the structure of the protostellar cloud at the core of each collapsing halo is not significantly different from that of a halo with a soft uv background. however, the density of the primordial gas in these halos increases as the lw Background increases.    we show that the main mechanism for this change is due to the dissociating of molecular hydrogen from the central halo by the ultraviolet radiation from the light - emitting diode ( e.g., x - ray ) field. using a model of the chemical evolution of structures at high redshift, we calculate the mass of the proton - rich protostellar cloud at r=0
the amount, distribution and kinematics of the diffuse stellar component in nearby galaxy clusters may provide information on the cluster accretion history and evolutionary state, as well as about the evolution of cluster galaxies.   the recent discovery of three planetary nebulae ( icpns ) moving at @xmath0 kms@xmath1 along the line - of - sight of ngc 4406 in the virgo cluster core has been used to map the spatial distribution and kinetics of the diffusible stellar component, i.e. the_acluster light ( icl ), in the nearby clusters. here  , we review the results of several studies that have investigated the properties of the icl in the core of the nearby vir go cluster, hydra  i and coma, and compare them with those of the @x math34959/5007  single emission line candidates for the same region. using a combination of spectroscopic and computational techniques, we show that the distribution of the ice - like stars in the two other clusters is similar to that of the central virgo core region, with the exception of the presence of streams of icl around the center of the vir
we present a new model of the extendedness of a particle in the kaluza - klein theory.   the model is reduced from the standard model by adjusting the size parameters of the compact manifold.    the magnetic and electric dipole moment terms are introduced in the new model. for the first time  , we show that the edm term can appear in the original model, but the expected magnitude is far less than the experimental upper bound even at the present time. although the result is numerically not interesting, it has some qualitatively - interesting features such as the dual relation.
the mass of the higgs boson, @xmath5, is essentially a free parameter of the standard model ( sm ).   the study of high - energy weak - boson scattering at two loops ( with neglect of trilinear couplings ) leads to a perturbative upper bound on@xmath6 which depends on the considered centre - of - mass ( c.m. ) energy. for the fermionic case @xcite, this bound is relatively modest, below 15% at ~19  tev if the on - mass - shell renormalization scheme is employed. in the present paper, we find the two - loop corrections to the partial widths of these decays to pairs of fermions and intermediate bosons at ~3  gev using the goldstone - bosonal equivalence theorem. by taking into account the fact that the main effect of the pairwise interaction is the presence of a strong self - coupling, the results are in good agreement with the results of previous studies.
we explore the intricate nonlinear properties of measurement - induced chaos in a cavity quantum electrodynamical scenario.   we consider an ensemble of identically prepared two - level atoms ( qubits ) which interact pairwise with a single mode of the quantized radiation field and then one member of each pair and the corresponding cavity field are measured. conditioned on the measurement results, the unmeasured atoms are kept or discarded by a pair of optical conveyor belts. after each interaction, the remaining atoms form a new identity of smaller size and the state changes of the remaining two - levels atoms are described by an iterated nonlinear quantum transformation. as a generalization of the tavis - cummings model @xcite, we show that this nonlinear dynamics can be used to implement a schrdinger microscope capable of amplifying the distinguishability of non - orthogonal quantum states.
subjet studies of hadron collisions are a powerful way to gain a deeper understanding of the structure of the hadronic jets.   they are particularly interesting when the resolution scale is large enough for perturbation theory to be valid, but small enough for the typical multiplicity of subjets to be large. in this work   we use the ` inclusive @xmath0 algorithm'with the `@xmath6-recombination scheme'to study the subjet structure of two - jet events in a hadron collision experiment. using the new algorithm, we find that the size of the jets is determined by the distance between the individual hadrons and the jets, which is well within the range of dimensionless resolution scales allowed for in perturbative qcd experiments. as the resolution of the resolution increases, the fraction of jets that are resolved into two or more subJets increases, until for small @x Math1 every jet consists of many subjels.. the most interesting region is the intermediate one, in which the resolutionscale is larger enough for both types of calculations to be viable for perturbed control tests.
quantum theory has been the subject of much discussion, but never conclusively solved.   the most profound reason of uneasiness with quantum theory, despite its indisputable successes, has been expressed by richard feynman : “ you see, my physics students don’t understand it either.”   that is, because i don't understand it. in this article   i would like to revive, from a new viewpoint, a somewhat old fashioned discussion, which recently seems to be all but extinct. as goes without saying, every contribution, correction, criticism or suggestion is greatly appreciated. however, until today any fundamental question in this respect seems to have been considered a lack of scientific soundness. from an epistemological point of view, since all the fundamental problems are still far from any solution, the fact is not easily understood, since both quantization and second quantization provide an even more problematic conception by their inherent infinity problems. for this reason  , i suggest that the discussion, mentioned above, might have its origins therefore not so much in a satisfying status quo, but rather in a absence of alternative concepts.
the main goal of the article is to show the principle necessity to take into account both correlated hopping of electrons and inter - atomic exchange for the correct description of metallic ferromagnetism.   the mean - field analyzis in the case of weak and intermediate electron correlations are investigated by means of the gutzviller wave function approximation and the stoner - wolfarth generalization of hirsch's theory. at the same time the mechanismes which are responsible for the ferromagnetic ordering around the point of half - filling are discussed.
the lightest supersymmetric ( susy ) particle is a favored candidate for the dark matter in the universe.   it is a weakly interacting and massive particle, and hence is frequently characterized as a wimp. here   we consider the effect of cp violation on the neutralino annihilation and scattering cross sections of the lightest susy particle in the minimal supersymmetry standard model ( mssm ) where the soft trilinear scalar couplings of the neutral - higgs bosons are all complex numbers, where subscript @xmath14 refers to the quarks. in part of susy parameter space   these cross sections are enhanced by the addition of softly cp - violating breaking terms to the higgs potential, or by integrating out heavy degrees of freedom that break the cp invariance of the higgens sector, such as heavy majorana neutrinos. in other parts of the model,   the effects are suppressed.
the einstein static universe has been of great interest in the field of general relativity and its extensions.   although the cosmological constant was soon dismissed after its original introduction in 1917, recent observations seem to indicate that the universe is currently undergoing a phase of accelerated expansion, consistent with the presence of @xmath2 ( now called dark energy ) in the einstein field equations. as a result, the idea that dark energy may indicate the need for a gravitational theory beyond general relativity has recently inspired a vast amount of research, in what is known as modified gravity or higher order gravity. in this paper   we analyze the stability of the e Einstein - static universe against homogeneous and inhomogeneous scalar perturbations in the context of@xmath0 gravity. here, we consider two types of models, fine - tuned and non - fined - tuned models, which are governed by the action @x Math7.\ ]. using these models, we show that both the solution of the field equations of general relativistic gravity and the model of the universe with a non - constant pressure can be considered as an einstein - static model. however, the latter is more stable than the former.
we investigate the effect of acceleration of noninertial frames on both bipartite and tripartite entanglement of dirac field using partial realignment criterion ( linear contraction ) @xcite as entangler quantifier.   our system consists of three observers ; alice, bob and charlie. in the accelerated frames, we consider only one observer ( charlie ) in the frame and then we do calculations for two accelerated observers ( bob and charlie ). to obtain the mixed density matrix whose dynamics are to be studied, we use the @xmath0-tangle and logarithmic negativity criterion for the measurement of tripartites and the partial realignment criterion (linear contraction ) for the measure of bipartites. with increasing acceleration,   the degree of entanglemons is degraded in all the subsystems of the dirac fields except for the single observer in the accelerator - accelerated frame and the quantum entanglements between the parties are not observed in any of the bipartitic subsystems. however, the genuine tri Partite Entanglement is still present in the case of the accelerated observers. under the same conditions, the uniform distribution of the three
we consider the low energy physics of a class of bosonic hamiltonians and show how they can be described by a set of emerging gauge theories, we also propose and design experimentally feasible ways to quantum simulate them.   our hamiltonian describe two - species bosons hopping on a two dimensional square lattice. depending on the tunneling geometry of one of the bosonic species ( referred to as auxiliary particles ), one obtains different low energy emerging gauge theory for the other particles. in the present paper   we find that the low - energy sector of the remaining bosons can always be characterized by an emergent gauge theory.see research article http://www.biomedcentral.com/1471-2148/7/8/9/11/10/3
the dyson - schwinger equation ( dse ) technique has been successful in modelling a number of light meson phenomena using the quark propagator.   the aim of this paper is to formulate an extension of the dse technique to the realm of heavy quarks, that is, mesons containing charm quarks or bottom quarks such as @xmath1 and@xmath0 mesons.    we develop the basic formalism for the heavy quark propagateator and consider the bethe - salpeter equation for mesons consisting of one heavy and one light antiquark. by means of numerical calculations,   we show that the symmetries of hqet are preserved within the limit of the Dse technique for bound states of dark quarks and light antiquarks when the propagator is free of timelike poles near the bare fermion mass pole @x math9.. however, we are unable to find solutions to our model bse because of spurious poles in the model qcd propagators. at the present level of approximation, we suggest ways in which the model can be improved to overcome this problem.
the problem of obtaining a sharp lower bound for the number of distinct distances guaranteed to exist in any set @xmath0 of points in the plane, originally posed by erds @xcite in 1946, is studied in this paper.   it is shown that the problem can be reduced to an incidence problem between points and a certain kind of curves ( helices or parabolas ) in three dimensions. as we show, sharp upper bounds on the numbers of such incidences translate back to sharp lower bounds at the same time.
we study the slip boundary condition for single - phase flow past a chemically patterned surface using molecular dynamics ( md ) and continuum simulations.   we show that modulation of fluid - solid interaction along the patterned surfaces induces a lateral structure in the fluid molecular organization near the surface, which results in various forces and stresses in the liquid molecules that vary along the surface. as a consequence, a general scheme is developed to extract hydrodynamic information from md data. with the help of this scheme,   the validity of the navier slip boundary conditions is verified for the chemically patterning surface, where a local slip length can be defined. by changing the ratio of the pattern period to the slip length, two distinct slip regimes are found : one with a homogeneous surface and the other with an effective slip length that can be controlled by surface patterning.
modified theories of gravity ( mg ) have received a lot of attention in recent years.   several unexplained phenomena such as the observed accelerated expansion of the universe, spatio - temporal variation of the fundamental constants and dark matter can in principle be explained by modifying general relativity ( gr ) on large ( astrophysical and greater ) scales. in this paper   we consider deviations from gr exhibited in theories that rely on screening of the scalar field, i.e. the dilaton and the vainshtein screening mechanism. for each of these mechanisms, we find that the effects of the fifth force are suppressed in regions where the screening mechanism is not applied. to test the validity of our results, we apply tests of the equivalence principle and the khoury & weltman screening mechanism to the @xmath0 and dgp models of mg and find that they do not match the predictions of gr within experimental bounds on small scales.
the leiden  berkeley deep survey ( lbds ) is a collection of optical and infrared observations of high - redshift radio galaxies in the hercules region of the sky.   the results of these observations are compared with those of previous work using the westerbork synthesis radio telescope ( wsrt ) at 21  cm ( 1.412  ghz ) with a 125 beam @xcite, and with spectroscopic observations of 85% of the optically identified sources using the 4-m mayall telescope at kitt peak for the purpose of faint galaxy and quasar photometry from the millijansky flux density limit at 1.4  gh zn ( @xmath16  mjy ). to study the evolution of the hosts of these radio sources, it is essential to identify optical / infrared counterparts to a majority of the radio sources. here   we present essentially complete optical identifications for a subsample of the lbds, together with infrared@xmath5-band observations of most of the sources selected by radio selection at this limit. among the sources,   only one source was found to be too faint to be considered as a candidate for radio selection.
observations indicate that globular clusters ( gcs ) contain practically no gravitationally bound dark matter ( dm ).   how did these objects form? assuming a baryon - only universe, @xcite suggested that gcs formed via gravitational collapse of non - linear baryonic over - densities shortly after recombination. here  , we show that this model is not the case. in the presence of a stream velocity,   the baryons decoupled from the photons and their subsequent evolution was dominated by the gravitational potential of the dm, and their relative velocity with respect to the Dm, called the  stream velocity ", became supersonic. for an interesting range of masses, the spatial offset is larger than the virial radius of the parent dm halo, allowing the beryonic clumps to survive as independent dm - free objects. using a cosmological hierarchical structure formation model, we suggest that these objects may have evolved into gcs ; the corresponding gas - poor dm halos may be present day dark satellites or ultra - faint galaxies.
the muon anomalous magnetic moment ( muon g-2 ) is one of the most precisely measured observables.   the theoretical prediction from the standard model of elementary particles ( sm ) by several groups has suggested that there is a discrepancy between the experimental result and the sm prediction. in this paper  , we consider new physics models where muon has new yukawa type interactions with new particles to generate new contributions to muon G-2. for example, in a model where the chirarity flip of muon occurs only in external line ofmuon g - 2 diagrams, it is necessary to introduce the relatively large yukawan coupling and the electroweak scale new particles. on the other hand, in another model, in which the chidarity flip can happen in the internal lines of muons g - two diagrams, we can obtain favorable g-two contributions without large yucawa couplings, and they are also consistent with the precision electroweak observables.we also expect these particles may be observed directly and/or indirectly at the lhc experiment.
x - ray observations of seyfert 1 nuclei have provided direct evidence for significant quantities of optically - thin photoionized gas along our line - of - sight to the central x - ray source.   this material, which has become known as the warm absorber, is a blend of the photoelectric k - shell edges of ovii and oviii ( at 0.74kev and 0.87kev, respectively ) which are imprinted upon the primary x -ray spectrum when the line -of - sight passes through the warm absorbing material. in this contribution  , i shall describe two studies that address the physical nature of the Warm absorber. within the context of a one - zone photoionization model, it is shown that the ovii edge depth is essentially constant whereas the oviii edge depths are strongly anti - correlated with the primary X - ray flux. however, the constancy of the ov ii edge is inconsistent with the observed variability of the warm absorbber. using a two - zone model,   i show that much of the variation in the ovarian edge depth results from a distant, tenuous warm absorbers which has a long recombination timescale and so is not
the incorporation of fermionic degrees of freedom in the simulation of lattice qcd is a longstanding problem.   the hybrid monte carlo algorithm @xcite is the state of the art algorithm for the simulations of full qcd on the lattice, but the cpu - time required for a full sweep over the lattices increases by a large ( order 100 ) factor with the increase of the number of links in the update step. in this paper   we propose a new finite step - size updating algorithm that can be used to speed up the computation of the topological sector of qcd in a multi - level metropolis scheme. using the hopping parameter expansion and the noisy estimator of the fermion determinant  , we show that the computational time of the simulation can be greatly increased by a factor of 100. as a proof of the proposed method we present numerical tests with the two flavour 2d schwinger model with wilson action and two - flavour qcd with wilson action under two - level functional boundary conditions.
a. poincar s ideas about the interdependency between properties of space - time and properties of measuring instruments are discussed.   the existence of such a connection can be shown by an analysis of a simple and well - known example. in this example, we consider a reference frame, rigidly connected with the earth surface, as the inertial one ( ifr ). to describe gravitation in inertial and proper frames of reference  , we suppose that in pseudo- euclidean space -Time gravitation can be described as a tensor field @xmath6 of spin 2, and the lagrangian, describing the motion of a test particle with the mass@xmath5, is given by the proper frame of reference ( pfr ). for this reason, we accept according to the special relativity that space - times in the ifr are pseudo - euclidesan. however, it can be argued that if we proceed from relativistic relativity of space / time in berkeley - leibnitz - mach- poincarsi ( blmp ) meaning, then the differential metric form of spacetime in pf is of the form @x maths2 in this
the galaxy - galaxy lensing experiment is a powerful tool for studying the angular clustering of galaxies and quasars.   it is well known that the correlation between foreground galaxies and the background shear surrounding these galaxies can be measured by correlating the tangential shear of background galaxies surrounding foreground galaxies with the surface density of background objects. in this letter  , we present two inversions of the observed galaxy - shear - foreground galaxy correlation function to estimate the cross power spectrum between galaxies and mass using the sloan digital sky survey data. here, we show that the kernel involved in the projection of three dimensional clustering to the two dimensional angular space is significantly different from the kernel used to measure the galaxy - dark matter cross - power spectrum as a function of the number counts of background sources. under the assumption that the foreground galaxies are assumed to trace the mass distribution responsible for weak lensing of their background sources, we find that the resulting galaxy - mass correlation function is more sensitive to the presence of more than one galaxy in each dark matter halo than the previously reported correlation function ( @xmath0cdm cosmology ; p  <  0.05 ). on the other hand,
the theory of cosmological perturbations is a cornerstone of the study of the early universe, since most of the accessible information from this epoch is believed to be contained in the Cosmological fluctuations that are observed in the cmb and, more indirectly, in the large scale structures.   an important step in the elaboration of an early universe model is to be able to deal with the origin and the early evolution of cosmsological perturbed quantities. in brane cosmology, where ordinary matter is confined in a higher dimensional spacetime embedded in a braneworld, one can distinguish three main approaches to tackle the problem of how to describe the cosmology of the brane in this context. in the present work  , we present how one can describe the branes for any gauge chosen in the bulk by comparing the perturbed and unperturbed values at the same coordinate point. in order to do so, we use the standard metric - based formalism, which has been used in standard cosmology for a long time, and we show that it is possible to define meaningful ( linear ) perturbs for tensorial quantities defined on the submanifold using the standard theory of linear pert
the ads / cft correspondence in lovelock theory has been already discussed in the context of the shear viscosity to entropy ratio.   however, when we take into account the pathologies in ads black branes, the kss bound must be somewhat restricted. in this paper, we explicitly present the conditions for the occurrence of pathologies. using the conditions, we give a detailed analysis of lovelocock ads black Branes and discuss its implications in ads/cft.
tracking a lander on the surface of another planet with radio signals is an efficient way to observe its rotation.   this can be done by measuring the doppler shift of the radio signal between the lander and a large antenna on earth, like the ones of the deep space network ( dsn ). in this paper   we derive expressions of the signature of the martian orientation parameters ( mop ) in the Doppler observable and in the range observable from the geophysical models for the nutations, the precession, the length - of - day variations and the polar motion. since these rotational motions depend on the interior structure of mars, in particular the core dimension, density and state, and on the dynamics of the atmosphere and the ice caps and the co@xmath0 sublimation / condensation process, accurate measurements of these angles are very useful because additional constraints on the geophysiological models could be provided.
the cepheid period - luminosity ( pl ) relation is a classical tool widely used to estimate the distance to local group galaxies and to external galaxies with hubble space telescope ( hst ) observations, as well as, through the calibration of secondary distance indicators, to even more distant stellar systems.   the relationship between the pulsation period and the mass, luminosity and effective temperature of the pulsator is usually assumed to be metal - insensitive, but we have recently shown that it is not. in this paper   we show that the bolometric magnitude of the pl relation for metal - rich variables is, on average, fainter than that of metal - poor stars with the same period at different wavelengths, and that both the slope and zero - point of synthetic pl relations at different wavelength depend on the pulsators metallicity, with the amplitude of the effect decreasing from visual to near - infrared magnitudes. also the predicted plc relations at the different wavelengths turned out to be, in various degrees, Metallicity dependent : for a given period and color, metal -rich pulsators are brighter than metal -poor ones, whereas they are fainters if the @xmath19 color is adopted.
the ` @xmath3'scheme uses a two - color light field to interfere with one- and two - photon transitions in unbiased semiconductors.   the influence of the intrinsic phase on the dependence of the process on the relative phase parameter of the optical fields is well known, but the effects of excitonic effects on the interband interference have not been studied. here  , we investigate the effect of exciton lines and coulomb enhancement on the electronic properties of the `@xmath7'interband intersubband transitions in biased asymmetric semiconductor double wells using the effective mass, wannier exciton approximation and the _ ab initio   methods. by varying the phase parameters of the two colors of the light field,   we show that the absorption of the transition amplitudes at the band edge of the quenched transitions is enhanced by about 1.5 ev for all final energies above the band gap, which is much weaker than the one - photon absorption spectrum ( ~1.2 ev ). however, this enhancement is not due to the electron - hole attraction, as previously predicted from the independent particle approximation, but to the exciton - hole interaction.
how do galaxies form and evolve over time?   this is one of the most fundamental questions in astronomy, and the answer has far reaching implications for the accurate interpretation of any observations of galaxies throughout the universe.   it will make a significant difference in the interpretation of galaxy surveys if they preferentially detect populations of star - bursting dwarf galaxies, which do not trace the mass distribution in the universe, or if the galaxies we detect are massive spirals or ellipticals which do. as new techniques and instruments enable us to determine more and more accurate star formation histories for nearby galaxies over 90% of the lifetime of the universe  , we can hope to obtain a representative picture of galaxy evolution from our local neighbourhood, and with it the ability to predict what galaxies look like at all redshifts.
the eclipses of the 11th magnitude star ee cep have been observed with a  period of 5.6 yr from the early 1950-ies.   their depths change in a wide range from about @xmath0 to @x Math1 ( see *???   * ), however all of them show the same features : they are almost gray and have the same asymmetric shape. an observational campaign organized during the 2003 eclipse @xcite, brought very good quality photometric data with a dense time coverage. for the first time it was possible to analyze the color evolution during the eclipse and not only their amplitudes. at the time of the next eclipse, which took place at the turn of 2008, a large amount of the collected data were deposited in the ncbi's archive. here   we present the results of the analysis of these data.
the casimir energy is the zero - point energy of the electromagnetic field within and without a perfectly conducting spherical shell in the bag model.   it is well known that the vacuum contributions to the baryonic number are independent of the bag radius and of the pion field strength, being the vacuum quark contributions which are analogue to the casimir effect in qed essential in the calculation of barionic observables. for the massless fermionic field inside and outside the spherical bag,   the zeta function of the operator associated with the field equation together with ( eventually ) some appropriate boundary conditions is needed. in this work   we discuss the renormalization procedure which is necessary to apply in this situation and, specifically, the differences occurring with respect to the case when one assumes that the field occupies the whole space.
turbulence in rayleigh - bnard ( rb ) convection with rotation has been studied extensively over the last three decades.   the interest has centered on whether the energy and entropy spectra will be determined by the kolmogorov ( k41 ) or the bolgiano - obukhov ( bo ) scaling. here   we investigate the crossover between the k41 and bo regimes by considering the rb convection under rotation. for a rb system, the dynamics is controlled by two dimensionless numbers : the rayleigh number ( @xmath17 ) and the prandtl number (@xmath32 ). to study the effect of rotation on the nusselt number, we have used numerical simulations of the same system with different degrees of freedom. using these simulations, we find that the temperature fluctuations in the rotation dominated regime are responsible for engineering a passage to the bo spectrum.
the theory of inflation provides one elegant mechanism for explaining the origin of the tiny primordial fluctuations that we see in the early universe.   it predicts that these fluctuations are caused by a rapid expansion of the space - time during which the quantum field is expanding at an accelerating rate, and that they are all in phase and adiabatic, with a background of primordial gravity waves. here   we compare the inflationary picture with that of ordinary particle physics, in which we know the background and can test anything we want up to a limiting energy scale. while the latter assumes a spatially independent quantum field, inflation predicts that the fluctuations are always fluctuating, even at very small scales, and have more or less the same amplitude at all length scales. however, the pattern that inflation predicts for them is fairly insensitive to the details of a particular model, though measurements have actually reached a precision that can test inflation beyond its most basic predictions and can even exclude individual models. as a result,   the overallflationary picture is in superb agreement with what is seen in all experiments so far, but it is important to test the underlying assumptions of the theoretical model further.
the vibrational spectra of infinite carbon nanotubes ( cnts ) are analyzed using brenner s empirical potential for hydrocarbons@xcite.   the full set of normal vibrational modes is obtained by the diagonalization of the dynamical matrix, and the mode symmetries are assigned according to commonly accepted rules. in this paper   we present results for armchair @xmath0 and zigzag @x Math1 cnt's with @x math7. a detailed analysis of the vibrational spectrum demonstrates that there can be modes with identical symmetry groups that give different contributions to raman spectra. it follows from the difference in the " fine " structure of these modes, and depends on whether vibrations of neighboring atoms are " in - phase" or " out - of - phase ".
we have performed monte carlo simulations of a model of a nanoparticle consisting of heisenberg spins on a simple cubic lattice.   the particle shape is spherical with radius @xmath1 ( in units of the cell size ) and the particle outer shell of spins having a width @x Math3 is considered as the surface. for this purpose, we are interested in a particle with a ferromagnetic core with uniaxial anisotropy along the long axis surrounded by a shell of pins with antiferromagnetic ( af ) interactions and also uniaXial aniospotropy. at each temperature  , the system is allowed to equilibrate during a number of montecarlo ( mc ) steps and after the magnetization is averaged over at least at least ~15 mc steps using usual heat bath dynamics for continuous spins.the results show that the core magnetization tends to shift towards the field direction driven by the fm coupling between them. in a similar way, the spins at the shell attain afm order although with a small net magnetization originating from the uncompensated spin at theshell surfaces.    more interesting is the thermal dependence of the interface magnetization
low energy nucleon - antinucleon annihilation is a fertile area for studying hadron dynamics and particularly pionization.   experiments give information on pion numbers, spectra, and correlations and seem to show little dependence on initial energy from annihilation at rest to kinetic energies of a few hundred mev. results do depend on the iso - spin and spin quantum numbers of the annihilating pair. understanding these results is a serious challenge to theory. in this paper   we develop a description of nucleon-antinuclear annihilation into pions based on the creation of a coherent classical pion wave in the annihilation process and the quantization of this wave using the method of coherent states.
we have studied the steady state of the branching - coalescing random walk ( bcrw ) and the asymmetric kawasaki - glauber process ( akgp ) in a one - dimensional out - of - equilibrium model with open boundary.   we have shown that the steady states of these two models can be obtained from two - dimensional representations of their quadratic algebras using the matrix product formalism ( mpf ), which is based on the yang - lee theory of equilibrium phase transitions. for each of the two models,   its steady state can be written in terms of interactions of single shocks. as far as a single shock structure is concerned   it is known that in an infinite system, and under some constraints, single shock or even consecutive multiple shocks may evolve in the symmetric simple exclusion process (asep ).    the steady State of the bcrW and that of the akgps can be derived from two- and four - dimensional representation of their quenchers by means of the mpf. in the first part of this paper  , we will show that the stability of the steadyState of the Bcrw and that
d - branes have been studied for many years and used to reveal nonperturbative aspects of string theory.   although several attempts have been made @xcite@xcite, they have not been studied so much in the context of closed string field theories. in this paper, we construct solitonic operators made from the creation and annihilation operators of second - quantized strings. acting them on the vacuum, we obtain brst invariant states, which can be regarded as states in which d-branes are excited. using these states,   we calculate the vacuum amplitude and show that these operators create two d - brane.
the ground state of graphene in a strong magnetic field at low temperature exhibits a rapid increase of the longitudinal resistance above a critical magnetic field ( @xmath0 ), indicating that the resistance is not caused by impurity scattering but instead is intrinsic to the state itself.   the ground state is also characterized by anomalous filling factors that reflect the unique degeneracies of the graphene electronic structure and the dirac - like nature of its electrons. here   we introduce a new approach to the problem of determining the insulating ground state in strong magnetic fields based on approximate su(4 ) symmetry of the hamiltonian. using this method, we show that the highest symmetry is so(8 ), with its generators identifiable with particle  hole and pairing degrees of freedom that have been discussed previously in the physics of graphene. for a given number of states and particles,   this symmetry is isomorphic to an so(9 ) symmetry used extensively in nuclear structure physics, which permits already - developed mathematics to be appropriated for the graphene problem, and suggests instructive physical analogies between two very different physical systems.
the cosmic evolution survey ( cosmos ) is a treasury program on the _ hubble space telescope _ ( _ hst _ ), awarded a total of 590 orbits, carried out in cycles 12 and 13.   the main purpose of the project is to understand the evolution of galaxies, active galactic nuclei ( or super massive black holes ), and dark matter halos together with the development of large scale structures in the universe. in order to carry out this project, we also need multi - wavelength data from x - ray, ultraviolet though optical to infrared and radio. among them, optical imaging observations made by use of suprime - cam on the subaru telescope are highly useful to investigate both photometric properties and photometric redshifts of the galaxies found in the cosmos field. in this paper  , we present details of observations, data reductions, calibration, and quality assessment for the twelve intermediate - band filters and nb711 in our subaru cosmos 20 project : six broad - band ( @xmath0,@xmath1, @x math2, @axmath3, @oxmath4, and @x Math5 ), twelve intermediate- and narrow - band filter sets (
collisional ring galaxies are believed to form when an " intruder" galaxy passes through the center of a rotating disk of a larger " target" galaxy, triggering a radially expanding ring - like density wave on the disk, causing massive star formation in the ring.   the cartwheel galaxy was discovered by zwicky ( @xcite ) at a distance of 121 mpc ( h@xmath4=75kms@x Math5mpc@x math5 ) and has a bright outer ring and an inner ring which is connected to the outer one with a series of spokes. here   we report the first detection of the distribution of hot dust throughout the galaxy and its nearby companions using the isocam mid - ir spectrometer.
the study of composite materials is of great interest in various fields such as aerospace engineering and industry in which the metallic materials can be advantageously replaced.   the modelling and numerical simulations of such composites are essential to the design with optimal electrical, mechanical and thermal properties, since authentic experiments are hugely expensive. in this paper,   composite materials constituted by a matrix ( modelling classical polymers or plastics ) reinforced by poorly or highly conductive inclusions are considerated. for the influence of the morphology and the variation of shapes for the homogenized thermal conductivity of such composite materials, we have taken into account several parameters such as the number, the volume fraction of each type of inclusions, and for the fibre type inclusions : the aspect ratio, the wave parameter and the volume fractions of the inclusions.the macroscopic thermal properties computations of the representative volume element ( rve ) are obtained by homogenization methods based on fft techniques which had been introduced in a previous paper ( @xcite ) that we have adapted for thermal analysis.    the rves are modelled as large 3d images ( over 7 million voxels per image).the results of the computed thermal properties of considered
the non - equilibrium random field ising model ( rfim ) is a model for the barkhausen effect in ferromagnets and more generally as a prototype for many experimental systems that show hysteretic and jerky behavior when driven by an external force.   the model is known to exhibit an out - of - equilibrium phase transition between a strong - disorder regime where the magnetization hysteresis loop is smooth on the macroscopic scale and a weak - disorder one where it has a discontinuous jump. here  , we study the robustness of this theoretical description with respect to a change in the dynamics of the @xmath1-spin - flip model. using a sethna - type algorithm that yields a deterministic evolution of the system with the external field, we show that the transition is not independent of the choice of the spin - flip dynamics. at criticality,   both the number and size of the avalanches are the same for the two modes of the dynamics, even though the strength of the transition depends on the order in which the spins are flipped.
weyl semimetals are three - dimensional topological states of matter, in which the conduction and valence energy bands with linear dispersions touch at a finite number of points, i.e., weyl nodes.   one of the topological aspects of weyl semmetals is that they host pairs of monopole and anti - monopole of berry curvature in momentum space @xcite, and the fluxes of beryllium curvature flow from one monopole to the other. in the presence of both a magnetic field and an electric field along the direction that connects two monopoles,   electrons can be pumped from one pole to another, leading to the adler - bell - jackiw chiral anomaly@xcite ( also known as triangle anomaly ). here  , we present a systematic calculation on the conductivity of topological semimetal in the high - field limit, and focus on the magnetoconductivity of the two - node model that describes a pair of weyld nodes with a finite distance in momentumspace. by applying a strong - field approach, we show that the conductivities of the electron - to - electron transfer from one node to
the near infrared camera and multi - object spectrometer ( nicmos ) is the  only  near infrared instrument capable of high resolution, high fidelity polarimetry needed to examine the scattering geometry and materials in many types of astronomical objects.   however, there have been recent reports of a systematic residual instrumental polarization of @xmath6 @xcite that would seriously compromise studies of objects such as active galactic nuclei and regions within circumstellar protoplanetary disks ; they typically exhibit polarizations of@xmath7. a comprehensive study of this residual polarization was carried out by ( *???   * b06 ), who found a residual excess polarization of ~1.0   for @x Math8 in the nic2 camera. prior to this work, observations of only one polarized and one unpolarized standard have been made, each at only two celestial orientation angles. therefore, until now, it has been impossible to entirely characterize the nicmos residual polarization. with these unknowns nullified by the multiple orientations,   the only remaining explanation for these residuals ( beyond intrinsically intrinsic polarization ) is that the photometry of the target is not consistent with the ground - based data. here
we investigate the second - order optical susceptibility and linear electro - optical coefficient of silicon carbide ( sic ) polytypes as well as bulk sic polytypes.   we find that the nonlinear optical properties of sic - nts are very different from those of carbon nanotubes ( cnts ), and also show a strong dependence on their diameter and chirality. in this work, we have carried out a series of _ ab initio _ calculations in order to analyze the linear optical features and underlying band structure of all three types of the sic- and x - ray - crystallized polytypes, and to identify differences in nonlinear photophysical properties between them. using both tight - binding molecular dynamics and @xmath6 methods  , we show that the first - order non - linear optical response of the wurtzite polytype ( 2h ) is more sensitive to the diameter than that of the other two polytypes ( 3c- and 6h - sic with a band gap of 2.33 ev and 2.39 ev, respectively ), while it is more insensitive to the size of the graphene sheet rolled up into a tubular form ( exbih
the osse instrument on the compton observatory has been monitoring the galactic center ( gc ) for 8@xmath0 years.   the 511 kev line emission from the gc has been detected, but the emission has never been unambiguously attributable to a given discrete source. here   we report preliminary results of the extension of the osse analysis into three new areas : the inclusion of observations in regions with no @xmath1 expectations of positron annihilation radiation, the extensionof the analyzed region to include a larger fraction of the galaxy, and the mapping of the positronium continuum component ( pcont ) of the total annihilation emission. based on the data - set of 1153 observations from the oswestry observational survey of the stars ( osse ) instrument,   it is shown that the majority of the emission is diffuse, and that the pcont flux values are derived from the combined measurement of the fainter planar and an unexpected enhancement of emission from positive latitudes.
we present a theoretical model for the scattering of both neutral and charged excitons with electrons in gaas quantum wells ( qw s ).   the model is based on calculating the exciton - electron direct and exchange interaction matrix elements, from which we derive the excitation scattering rates. using the lindhard model for potential screening, we show that the x - ray reflection spectra of the heavy - hole 1s neutral exciton @xmath1 ( trion ) are much more efficient than those of the negatively charged exciton@xmath2 ( trions ) due to their smaller binding energy, while they are also more efficient in the case of the 2d trion, as compared to the bulk trions @xcite. by taking into account elastic and inelastic scattering processes,   our model is validated by considering photoluminesence measurements on a mixed type i  type ii gaas / alas qw ( mtqw ) structure @xaite.
abstractthe large area telescope on the _ fermi gamma - ray observatory has detected numerous young pulsars, as well as recycled millisecond pulsars ( msps ) in close binary systems.   recently, three redbacks have been observed to transition between radio pulsar and accreting state on timescales of years : psr j1023 + 0038@xmath02452i in the globular cluster m28 @xcite, which was initially misclassified as a cataclysmic variable ( cv ) because of the similarity of its optical emission - line spectra and luminosities to those of the @xmath1-ray source. here  , we report on the discovery of a second cv, 1rxs j083842.1@x Math0282723  in the error circle of 3fglj0838.8@x math02829 , which is probably an asynchronous polar ( am herculis star ). using x - ray and optical time - series data from the all - sky survey of the same system, we identify a second black widow ( bw ) pulsar system in the same error circle, xmmu
reed - solomon ( rs ) codes are one of the most widely used error - correcting codes in digital communication and data storage systems.   the nature of multiple error - and - erasure decoding is to erase some of the least reliable symbols since those symbols are more prone to be erroneous than the ones that are covered by the covering codes. here, we design a rate - distortion framework to analyze the asymptotic trade - off between performance and complexity of multipleerror-and-erasure decoding of rs codes and propose a group of multiple - decoding algorithms based on this approach that achieve better performance - versus - complexity trade -off than other algorithms. for each of these algorithms, we present a set of patterns that can be used to construct the " best " set of erasure patterns and then attempt to decode using each pattern.. the algorithm that achieves the best trade - Off turns out to be an error - only decoding using the sets of patterns generated by random codes combining with covering codes such as random codes.
we have performed a spectral aging analysis of 13 large, powerful fanaroff - riley - ii ( frii ) radio galaxies with the vla using multiple configurations at 330  mhz, 1.4, 5 and 8  ghz @xcite.   the sources span the redshift range of @xmath0 and have angular extents@xmath1. using a large combined dataset comprising our radio galaxies and others from the literature   we have revisited some well known radio galaxy correlations, the results of which are presented here.
the ensemble structure function of the sa94 qso sample is studied in the r - band.   the variability properties of the sample are investigated by observing them simultaneously in two or more wavebands and the observed trends are analysed with the aid of other statistical indices. a strong correlation between the variability index and the absolute magnitude and an almost equal anticorrelation with redshift   is observed, which may be interpreted as an anti - correlation between amplitude of the variability and wavelength in the individual objects. at low redshift the variability amplitude decreases with increasing wavelength, whereas at high redshift it increases with increasing luminosity. this variability - frequency dependence is consistent with the results obtained for individual objects at low Redshift by edelson et al. ( @xcite ), paltani & courvoisier ( @excite ) and kinney et al. ( @incubate ). however the variability - redshift correlation could be due to an evolutionary effect, in the sense of a higher activity in the early phases of the agn life.
we investigate the evolution of spatially homogeneous cosmological models with a cosmology constant in line with the dynamical systems methods presented in the book edited by wainwright & ellis @xcite.   we focus on the friedmann - lematre models, which are isotropic about every point, corresponding to a six - dimensional isometry group. for a perfect fluid,   the fluid motion then coincides with the congruence normal to the symmetry surfaces, and the models are fully specified by the length scale factor @xmath11 and a parameter@xmath12. using these models as an example, we show that the model evolution proceeds in a similar way to that of more general models, with the main difference being that the two - component fluids are not always the same, but they can be considered as orthogonal models of type i and ii. the section is concluded with an investigation of tilted l - type v models, who turn out to give us reason to be cautious about the implications of the important wald theorem.
we present the first results from a new radial velocity survey of the sextans group dwarf spheroidal ( dsph ).   the new data show an almost flat velocity dispersion to large radii, with some evidence of a fall - off in the outer parts similar to that seen in draco and ursa minor  . surprisingly, sextan appears to be kinematically cold at the very centre, and this is the second localised cold population we have observed in a dSph.    we suggest that the nucleus of the Sextans dsoph contains a dynamically separate component, possibly the remains of a star cluster dragged to the centre by dynamical friction.
the quark model has been used with success for the description of many important properties of hadrons, as well as the existence of multiplets, their quantum numbers and the magnetic moments.   the use of constituent quark models ( cqm ) for baryons has been extended to include the excitation of the baryon resonances and the decays. in this article   we review the current state of the art in the calculations of the photocouplings for the excitations of thebaryon resonance energy and the short range properties of the quark structure.
in many applications where high frequency data are observed, we wish to predict the next values of this time series through an online prediction learning algorithm able to process a large amount of data.   the classical stationarity assumption on the distribution of the observations has to be weakened to take into account some smooth evolution of the environment. to adapt automatically to this smoothness, usually unknown in practice  , we propose to use an exponentially weighted aggregation of several such predictors, with various tuning parameters. as an application, we focus on a particular locally stationary model, that of the time varying autoregressive ( tvar ) process. here, we consider two possible aggregation schemes based on exponential weights which can be computed recursively for the aggregated predictors under the following main assumptions : ( 1 ) the observations are sub - linearly with respect to a sequence of random variables with possibly time varying linear coefficients and ( 2 ) the predictors to be aggregated are lipschitz functions of the past and ( 3 ) the predictions are not assumed to be generated by an underlying stochastic process.we show that the proposed aggregation methods provide a solution to this question, in the sense that they give rise to recursive adaptive minimax
filaments are ubiquitous structures present in both low- and in high - mass star - forming regions.   the herschel _ results have focused special attention on the formation mechanism of filaments, and on understanding their role in the star formation process. in this paper   we present an analysis of filament properties obtained from the column density maps of the lupus 1, 3, and 4 subregions of the scorpius centaurus ob association, produced by the photodetector array camera and spectrometer ( pacs ; @xcite ) and the spectral and photometric imaging receiver ( spire ; @xmath5 m ) on - board the _ hersc Helicherschel_ space observatory. using a new pipeline and updated calibration files, we show that the observed filaments are characterised by a narrow distribution of widths, with a median value of 0.10@xmath40.03 pc, which corresponds, within a factor of 2, to the sonic scale below which interstellar turbulence becomes subsonic in diffuse gas. for the lower column density filaments these values are probably due to external pressure, while for the higher column density ones they are likely to be due to
the rastall s theory of quantum effects is a classical, effective implementation of the loop quantum cosmology effective equation.   it is based on the observation that the conservation laws are tested effectively only on flat spacetime @xcite. in this paper  , we show that the rast all s theory can be used to construct a quantum cosmological model of the present universe, which is unique when a confrontation with observed observations is made.
we present a kinetic monte carlo ( kmc ) approach to the dynamics of a binary lennard - jones system around the glass transition temperature.   the model is a binary mixture of @xmath3 atoms in a cubic box with periodic boundary conditions, where @x Math4 of the atoms are of type @x maths5 and @x math6 of the atom of type@xmath7. the system is simulated by means of a stoddard - ford shifted, truncated version of the potential energy surface of @xcite, with a cutoff at @xMath25, along with the minimum image convention @xa2 +. using the kmc approach, we show how the simulation of the system can be extended to a much longer time scale than conventional molecular dynamics ( md ) simulations, and that it can provide useful information on the slow barrier crossings and localised rearrangements at low temperatures.
the search for neutron stars in supernova remnants ( snrs ) has been dominated by the discovery of young radio pulsars in the crab nebula @xcite and by the identification of the central compact object ( cco ) in the snr @xmath7.   recently, however, a wide variety of other types of neutron stars have been identified, from anomalous x - ray pulsars ( axps ) to soft@xmath2-ray repeaters ( sgrs ), to nearby thermal and radio quiet neutron stars with high inferred magnetic fields. here   we describe the results of a survey of six subsamples of snrs where the diameter is large enough to cover the area where the size of the star would be within the range of velocities that the acis - i detector at the _ chandra x - rays observatory can observe with its 2.5-m detector. using these subsamples, we show that the majority of the snrs are likely to be very young neutron stars ( ~3 billion years old ), and that the density of the core collapse supernovae is about 1.5 to 2.0 times higher than expected from the age of the universe
we investigate how a neutrino asymmetry affects the weakly interacting massive particle ( wimp ) abundance and its annihilation cross - section.   the standard model of dark matter assumes no asymmetry between neutrinos and anti - neutrines, but we find that an asymmetry in the number of neutrids leads to an additional contribution to the total energy density of the universe and thus to a smaller wimp relic abundance at the freeze - out of the weak interaction rates. this effect is independent of the particle mass and is most likely due to the existence of a lepton flavour asymmetry which influences the neutron - to - proton ratio at weak - interaction - Freeze - out, and thereby the @xmath17he - abundance.
the hst quasar absorption line survey was an hst key project for cycles 1 - 3, with carryover observations extending into cycle 4.   the survey had the ambitious goal of obtaining a large and homogeneous catalogue of absorbers suitable for the study of the nature of gaseous systems and their evolution. while the original scope of the survey was reduced by the servicing mission, the key project still successfully observed 89 quasars with the higher resolution ( r@xmath3 ) gratings of the faint object spectrograph. in this review   i will give examples of how hst has contributed to these studies.
the unitary - evolution - based quantum computation model ( uqcm ) is a well - known model of a quantum computer ( qc ).   it is a quantum version of the reversible classical circuit model, where the bits are replaced by the qubits, and the logic gates are replaced with the quantum gates ( coherent unitary evolution ). in this paper  , we present a new model of the qc, which we call " hybrid quantum computation models " ( hqcm).the aim of the present investigation is to develop a theoretical understanding of the hhqcm, where part of a Quantum Circuit is simulated by unitary gates and the rest by measurements on small graph states. for the experimental optimization, we investigate the effects of the measurement bases for the quantum circuits on the computational efficiency of the computations performed in the uq cmcs and the mqcmcs.we find that the results of the experiments show that the performance of the calculations run by the uxcmcs is significantly higher than that of the ccmcs, and that the performances of the operations run by both the uctcm and the turing machines are significantly lower than those of the other two models.the h
classical random walks ( crw ) play an important role in classical algorithms and have many applications in many realms of science.   while in the quantum worlds, quantum random walk ( qrw ) are markedly different due to the phenomenon of interference, which might lead to extensive applications in quantum information science. in this paper  , we design an experimental scheme of qrw by using linear optical system. here, we employ photon s spin angular momentum ( sam ) as " quantum coin" and orbital angular momentum space as one - dimensional walk space. for each step of the random walk,   we randomly choose a side of the coin based on the results of tossing'quantum coin' and the direction of " quantum walker " walks to every one step is decided by the results from tossing the'quantum coins'.the experimental results show that qrw is more efficient than crw when the number of linear optical elements is increasing.
sio masers located in the extended circumstellar envelopes of late - type giant stars are believed to be reliable tracers of the galactic dynamics since they can be treated as point - like objects and are not subject to non - gravitational forces such as magnetic fields or stellar wind collisions.   the australia telescope compact array ( atca ) has been used to perform high - angular - resolution observations of sio maser line emission from the galactic center ( gc ) at 86 and 43 ghz in five sessions ( 2006 june 9, 2006, june 10, 2007 and 2008 ) with a total of 1,929 observations of the sio maser lines at two transitions ( v=1, j=21 ( 86 ghz ) and v=2, j = 10 ( 43 ghZ ) ) within a few parsecs from sgr  a*. the results of the atca observations show that there are no significant differences in the number and spatial distribution of sialic acid ( sa ) maser lines at the gc between the two timescales ; however, the mean distance of the sa maser trails is significantly larger than that of the gas phase of the galaxy.
we present a novel approach to the explicit construction of liouville  integrable coupled systems of odes endowed with lie  poisson symmetries.   we show that the construction of poisson   lie groups as deformations of lie bialgebras can be systematically obtained by applying the so - called  coalgebra symmetry approach " to finite dimensional integration of systems of first order odes. in particular, we apply the formalism here introduced in order to obtain new integrables of certain lorenz   @xcite and rssler  @xcite systems, as well as of some coupled versions of them.
we investigate the occupied and unoccupied electronic structure of the heusler compound co@xmath0mnsi at room temperature by means of photoemission spectroscopy.   we use the fully relativistic one - step model, in its spin - density matrix formulation, to calculate the spin - polarization vector of the photoelectron current for the surface region around the fermi energy of the metal @xcite. using this approach we find a 93@x Math1 polarized surface resonance in the visible spectrum of co@Xmath0 mnsi. from the theoretical point of view   this is the first example of a large surface spin polarization in any ferromagnetic metal with a nonzero total spin polarization close to 100@x math1. within this state - of - the - art analysis   it is shown that the interaction of the outgoing photoelectrons with the rest system is strongly influenced by the spin polarization of the incoming photoelectronic states. as a result,   the electrostatic interactions between the outlying photoelectrode and the rest systems are stronger than those between the incoming photoselectron and the center of the photocurrent, which is relevant for applications.
mixture models are commonly used in statistical pattern recognition and machine learning.   they offer a mathematical basis to explain data in fields as diverse as astronomy, biology, ecology, engineering, and economics, amongst many others. here   we present a bayesian minimum message length ( mml ) inference method for the inference of mixture models using gaussian mixtures. unlike maximum likelihood ( ml ) or bayesian maximum _ a posteriori probability ( map ) estimation, mml considers the number and precision of a model s parameters, and considers the problem as encoding first the parameter estimates and then the data given those estimates ; the parameter values that result in the least overall message length to explain the whole data are taken as the mml estimates for an inference problem.the mml scheme thus incorporates the cost of stating parameters into model selection by considering the number of parameters and the precision of the model s components. from the results of this work  , we show that mml - based inference can be used to model some observed data using a mixture distribution of probability distributions of the form : @xmath1 where @x math2 is a 3-dimensional datum,@xmath4 is the numberof mixture components,
deryagin, grigoriev, and rubakov ( dgr ) has previously shown that the instability of the fermi surface under the formation of cooper pairs of quarks is suppressed at large but finite @xmath0.   the purpose of this paper is to see whether this limit is relevant for the physics of high - density qcd at@xmath13. in this paper  , we find that at any fixed value of the chemical potential @x Math14, in order for the dgr instability to occur we require the number of colors @x math0 to be larger than some minimum value @x maths15, which grows with @xMath14.    what is surprising is that even for moderate values of @x mathematics14, the minimum value  is very large ( of order of a few thousands for a modest chemical potential  = 0.16 ). therefore   one should not expect the large @x mathematician0 limit to be of direct relevance for physics with ~1,000 nm chemical potentials at finite densities.
the surface phonon on the surface of a diatomic linear chain of atoms is presented.   the model is extended and reinterpreted to give simple explanations of some other localized modes, such as localized vibrational normal modes at frequencies inside the gap between the two - body problem and the quantum treatment of electrons in single - particle approximation @xcite, and in the new field of " photonic band - gap systems" .
we consider the possibility of predicting lepton mixing angles from first principles, in the framework of the inverse or linear seesaw mechanisms to generate light neutrino masses.   an attractive phenomenological ansatz for leptons mixing  @xcite is the tribimaximal ( tbm ) one which is equivalent to the following values for the lepton Mixing angles : @xmath21,@xmath22 and @x maths23.    we give two simple @x Math0 flavor symmetry realizations of the tbm lepton mixings within the above seesaw schemes.. the results are compared with the current neutrinoless double beta decay data.
high redshift radio galaxies ( hzrgs, @xmath8 ) are among the most evolved and most massive galaxies in the early universe.   they are most likely located in dense ( proto)cluster environments and have properties that would be expected of forming central cluster galaxies. here   we report on the discovery of a substantial overdensity of ly@xmath0  emitters around tn j13381942 at a redshift of 4.1 @xcite by narrow- and broadband imaging with the 8.2 m vlt kueyen ( ut2 ) using the imaging mode of the focal reducer / low dispersion spectrograph 2 ( fors2 ). for the detection and photometry of objects in the images  , we used the ntt imaging data, taken on 1998 april 27 and 29 under nonphotometric conditions with susi2, to provide @x Math22- and @x math23-band magnitudes for candidate emitters where possible. from these magnitudes, we identified 64 hzrs at redshifts of 6202, 6195, and 1650  at @xXmath15, 6200, and 6200  at
@xcite has recently reported the discovery of a new class of cool objects, such as m stars or brown dwarfs, closer than 5 parsecs.   they used a novel classification scheme for the classification of these objects based on a set of existing and new spectral indices that measure the most important features in the optical spectral range. here   we describe the development of this new classification scheme and its application to the search for cool objects in the solar neighbourhood.
the abelian sandpile model and rotor - routing model are combinatorial models of various dynamics on graphs that were rediscovered several times in several different communities, ranging from combinatorics to self - organized criticality, arithmetic geometry, and algorithms.   the main problem in these models is whether there is a canonical bijection between the elements of @xmath0 and the spanning trees of@xmath1. here   we show that there is no such bijection, for the monotonous configurations in the abelians form a group called the Sandpile group or the critical group of @Xmath1 ; it is also known as the picard group of the graph, which we will denote @x Math0.    we prove that if @x math1 is a _ planar _ ribbon graph, then miraculously, the action defined by rotor routing is independent of the choice of the basepoint and hence canonical. furthermore, this characterization is tight : only planar ribbon graphs have this property.
model stellar atmospheres constitute the basis on which we interpret stellar spectra.   our ability to produce " good " models including the necessary physical approximations and input data directly impacts the quality and reliability of the parameters we extract from observations : @xmath0, chemical abundances, etc. despite this complexity, simple one - dimensional, hydrostatic, lte models have been constructed, and used to study red supergiant ( rsg ) atmospheres with success. in this paper   i present the current marcs generation of such models, detailing some aspects linked to the opacity sampling approximation, and discuss possible non - lte effects on molecules. finally i present current efforts in hydrodynamical modelling, with encouraging results, but with their own limitations, hopefully alleviated in the near future.
the quark gluon plasma ( qgp ) is a deconfined state of matter which is expected to be formed in the heart of an ultra - relativistic heavy - ion collision, when the energy density is the largest.   the jet quenching effect is one of the most relevant as it has highlighted the production of a dense medium in interaction. however, a plethora of questions remains : does energy loss result from few strong scatterings in the medium or multiple soft ones?   how does it depend on the medium - length? what is the energy loss probability distribution of the partons?   they motivate the necessity to call for some more discriminating, and differential observables to characterize the qgp. here   we discuss the results of the alice experiment at the level of the experiment.
chemisorption on metal surfaces has been attracting a great deal of attention for over three decades.   its nature, however, despite quite involved experimental techniques and a number of data as well as many theoretical attempts, is far from being well understood. here  , we study how a competition between the ( repulsive ) dipole - dipole and ( oscillatory ) long - range indirect electronic interactions could influence ordered submonolayer structures as wellas their equilibrium thermodynamic properties ( phase diagram ).    this is done within a plausible two - dimensional lattice gas model which might describe linear chain structures for coverages up to 0.5.  in particular, we consider the ( 112 ) surface of bcc metals ( w or mo ) and the corresponding lattice of adsorption sites @xcite. 	 the model is used to calculate numerically the ground states ( @xmath4 ) and discuss their dependence on the model parameters. using the mean - field approximation, we also calculate the corresponding phase diagrams.
in this paper, we focus our attention on the energy extraction from higher dimensional black holes and black rings by the penrose process @xcite. using a catastrophe theory, we analyze the stability of the black ring and black hole solutions.   we first summarize the properties of black hole and black ring solutions in higher dimensions, which are described by a different form depending on whether a space - time dimension is even or odd. then we write the solutions in order. as for 5-dimensional objects, adopting a catastrophe model, we also analyze their stability.
the evolution of an initially given magnetic field in an incompressible flow of a conducting fluid is determined by the following equations : the magnetic diffusivity, the advected field, the stretching term and the diffusive term.   the relative importance of the two contributions on the right - hand side of is given by the magnetic reynolds number. for the prescribed velocity we refer to the kraichnan statistical ensemble @xcite, in which the field is assumed gaussian, homogeneous, isotropic and @xmath20-correlated in time. under this hypothesis   it is possible to assume for the initial conditions that the initial generation of the magnetic field is a persistent situation or not. as a result  , the evolution equations are totally uncoupled from navier - stokes equations. following this kinematic approach,   we thus proceed as if the initial field was an assigned random field : given the initial condition@xmath0 and appropriate boundary conditions, eqs..   completely determine the magnetic fields evolution.
the observations of very metal - poor damped lyman @xmath0 ( dla ) systems have opened a new window to study the chemical enrichment of the universe by the first generations of stars.   the observed abundance patterns of carbon, iron, and barium in these systems are well reproduced by comparing the observed elemental abundances with theoretical calculations of nucleosynthetic yields from hydrodynamical simulations. here   we show that the observed pattern can be well reproduced with the enrichment from a single core - collapse supernova that leaves behind a relatively massive black hole, under the assumption of inhomogeneous chemical enrichment at the time of star formation.
we report on the observation and study of magnetic quantum ratchet effect in ( cd, mn)te/(cd, mg)te diluted magnetic heterostructures and cdte / cdmgte quantum wells ( qws ) superimposed with lateral asymmetric superlattices. applying magnetic field @xmath2 along the growth direction   we observe that the ratchet current exhibits sign - alternating @x Math1-periodic oscillations with amplitudes immensely larger than the ratchets generated at zero magnetic field.   the results are analyzed in terms of the theory of magnetic ratchet effects in qw structures with a lateral asymmetry periodic potential  @xcite. using x - ray diffraction we show that the photocurrent generation is based on the combined action of a spatially periodic in - plane potential and the spatially modulated light due to the near field effects of radiation diffraction. corresponding theoretical analysis describes the experimental results.
solving system of linear equations ( sle ) is a common computational task in modern science, technology and engineering.   although classical algorithm for solving of sle is of polynomial complexity, the increasing size of sle causes the bigger processing time, which naturally provides a strong motivation for looking for better and faster methods of solving such problems. in this paper   we propose a quantum circuit for solving sle with use of qutrits instead of qubits based on direct construction of suitable quantum circuit which can be used to solve sle with three variables by using quantum operations of phase estimation, non - unitary operation on ancilla qubit, reverse phase estimation and finally measurement of an ancillary qubit/qutrit / qudit.
the cebaf large acceptance spectrometer ( clas ) @xcite has been used to measure polarization observables in the photoproductions of pseudoscalar mesons, vector - meson, double - pion, hyperon, and quasi - free off the proton and bound neutron.   these measurements include single- and double - polarization observable with combinations of polarized beam, target, and the polarization of the recoiling baryon. for each energy and angle,   a formally complete experiment requires at least eight carefully chosen observables from the clas collaboration. also, it is important to include in the analysis data from a variety of excitation and decay channels, as some of the missing states may couple only weakly to,   e.g., the @xmath0 channel. here  , we present examples of recent experiments that have used the new set of polarization observable data obtained from this experiment to identify resonances in the nucleon resonance spectrum.
the recent n@xmath0, co, and ar measurements by rosina ( rosetta orbiter spectrometer for ion and neutral analysis ) aboard the european cometary space mission allowed us to derive some clues on the nature of the ices accreted by comet 67p / churyumov - gerasimenko.   the results show that the majority of the icy material accrete in the protosolar nebula ( psn ) from oort cloud comets ( occs ) and jupiter family comet ( jfcs ), which are predicted to be the dominating c and n bearing species in the psn. however, it is still unclear from which of the two types of icy materials these comets preferentially accrete.. we propose that the origin of the ice from the occs may be related to the formation of clathrates in the interstellar medium ( ism ) at @xmath1150 k, where the gas trapped in amorphous ice is able to trap other gases such as carbon dioxide ( co ) and nitrogen oxide ( ar ). using a statistical thermodynamic model, we find that the ratio of ar to co in
the naked reissner - nordstrm ( r - n ) singularity is a classical general relativistic solution in electrovacuum.   the solution is expected to have a very limited meaning, due to the fact that such singularities can not be created neither by a gravitational collapse, nor by dropping a charge into the black hole. however it was discovered that the scalar field scattering problem on such a singular background can be still well defined @xcite, since the waves remain regular at the origin. despite the nice regularity property of the scattering problem, the spacetime is non - globally hyperbolic and the time evolution of the fields is not unique @xmath4 hilbert space. here   we analyse the properties of the effective potential for the scalars scattering and the geometrical optics limit of such a scattering problem. in the fifth section we define analytically solvable potentials that can give good approximations to the problem of the low damped qnm frequencies ( such that characterize the given scattering problem ). in particular, we focus on the quasinormal modes of the high damped quasi - normal modes which are in general used as a possible source of
the search for the first earth - twin has led to a considerable cross - disciplinary interest in the interplay between stellar and planetary properties to produce habitable worlds.   the classical assumption investigated by @xcite, i.e. the capacity for water to stay liquid on the planet s surface, may still be considered a prerequisite for the development and sustainability of complex life as we know it. here   we aim to refine this definition to encompass the gravitational and radiative influence of a second star on a terrestrial planet in the primary star s habitable zone ( khz ). using three exemplary binary - planet configurations, which will serve as test - cases for habitability considerations, we investigate the effects of the second star s radiation on the insolation of a planet in its host star s hz and compare the resulting effective radiation values to actual insolation simulations.    generalized, analytical estimates are developed and compared to numerical simulations, and the results concerning the behavior of the khz in binary star systems are presented.
the hyperbolic dispersion relation of an anisotropic medium, where the effective permittivity component ( @xmath2 ) along the direction perpendicular to the interface is negative, is obtained from full - wave numerical simulations of realistic structures.   a fitting procedure is exploited to get the dispersion relations from the field distributions obtained from simulation of realistic structure. for a homogeneous effective metamaterial,   the results are in good agreement with the experimentally observed properties such as near field focusing, subwavelength imaging, and negative refraction.
the polarization and lifetime measurements of @xmath0 in isotope have been used to assign the parity of different dipole bands through polarization measurements for detailed understanding of their configurations.   the results of polarization measurements along with tilted axis cranking ( tac ) calculations are used to obtain the shape parameters and quasiparticle configurations for different bands in @x Math0 in. a new level scheme of @xcite has been proposed for generation of high spin states in this region based on geometry consideration and geometrical models.
we summarize recent progress in the application of analysis techniques to determine the orbital parameters and the intrinsic spectra of components in multiple systems.   we discuss relations between these techniques and their applications in planet search programmes, where the emphasis is on the rich line spectroscopy of cool stars. at present, the use of broadening functions is restricted to very - short period close binaries, where rotational broadening hampers the detection and the analysis of the components. methods to separate and disentangle the spectra from observed multi - component spectra have served mainly in the area of detached, hotter stars. for the latter,   the improvement of templates and the increase in sensitivity in cross - correlation techniques has been driven by planet search programme applications.
the pion decay constant is examined with the kogut - susskind ( ks ) quark action via gauge invariant and non - invariant operators using all ks flavors.   the ks action has the well - known feature that @xmath5 flavor symmetry is broken down to@xmath6 subgroup at a finite lattice spacing, and hence the renormalization constant for the corresponding axial vector current in this channel receives no renormalisation. here   we extend the study to the pion decays, the new feature being the necessity of renormalized constants. by using the same method, we obtain a high - precision calculation of the pions decay constant without uncertainties from renormization.    we also compare the results obtained with gauge invariants to those with non - inv invariant ones.. the results show that the non - perturbative method is more reliable than the one - loop method for the calculation of these factors.
the choice of equilibrium for a large-@xmath0 gravitational system depends on the mean field potential corresponding to the smoothed out mass distribution of the system.   it has long been known that the phase space distances between trajectories moving on regular orbits generally diverge linearly in time  ( bt ), even for systems with smoothed background potentials that only support regular orbits. here   we show that, when the singularity in the two - body potential is removed, the exponential divergence timescale between neighboring trajectories does increase with @x Math0 and correlates with the evolution of dynamical variables like angular momentum. by using a newtonian model of the cosmological dynamics of self - gravitating particles  , we also show that the choice of steady state equilibrium can be used to extract physically interesting information about the evolution asymptotically of macroscopic quantities ( e.g., density and velocity dispersion profiles ) from the dynamical stability of trajectories.
cool stars form in a range of environments, from isolated bok globules to modest sized clusters containing 100 - 200 stars, and finally to large, dense clusters with thousands of cool stars and several to tens of ob stars.   this is in sharp contrast to ob stars, which form almost entirely in large clusters. here   we discuss the recent work by @xcite and others on the evolution of cool star formation in the context of giant molecular clouds and evaporating gaseous globules.
the effect of the finite carrier density on the character of the quasiparticles of a spinless holstein model@xcite has been analyzed using a recently developed weak - coupling theory.   while for very strong couplings, no significant changes are expected due to the existence of rather independent small ( self - trapped ) polarons with negligible residual interaction, a density - driven cross over from a state with large polarons to a metal with weakly dressed electrons may occur in the intermediate coupling regime. here  , we make use of quantum monte carlo ( qmc ) and exact diagonalization ( ed ) methods, and calculate the photoemission spectra for finite clusters at zero and finite temperature. owing to the limitations of existing algorithms,   we develop a new grand - canonical qmc approach which is free of autocorrelations and therefore enables us to study small phonon frequencies and low temperatures.
abstractthe effects of agn on star formation and the effect of star formation on agn triggering have remained uncertain due to the difficulties in gathering complete samples of galaxy - bh ( co-)evolution scenarios.   we use multiwavelength data from the goods and aegis surveys to investigate the incidence of agns and of x - ray absorption among star - forming galaxies at the redshift of 70@xmath3 m. we find that the incidence is low in most galaxies, but increases with increasing star formation rate ( sfr ) and the number of supermassive black holes ( smbhs ) in the host galaxy. during the deep buried phase of galaxy evolution,   the central agn is heavily obscured by surrounding gas and dust, before being visible in x - rays and/or optical regimes. however, during the gas - rich phase, the obscuration of the central accretion disk takes place on small scales, and is linked to the material in the hosts galaxy. here  , we show that the extent of this obscuration is dependent on the size of the smbh and the density of the surrounding gas / dust layer. for the most extreme agn, the central regions of
the problem of overcoming the problem of transmission loss for long - distance quantum communication is a challenging problem which seems not to have an apparent solution.   there have been several proposal on how to increase the efficiency of quantum information transfer including quantum repeaters ( employing entanglement swapping or quantum cloning ) and heralded qubit amplifiers ( e.g., a heralded noiseless amplifier of polarization qubits ). in this paper   we present a new approach to solve this problem by using quantum cloning machines ( qmcs ) to clone qubits and then amplify them with an arbitrary gain. as a result,   the amplifiers are more robust against transmission losses and can be used to improve the effectiveness of quantum communication.
convection is a major process taking place in reg giant ( rg ) envelopes.   the reference one - dimensional ( 1d ) model of convection is the mixing length theory ( mlt, @xcite ), which assumes a typical convective time scale estimated by convection velocity. however, experiments, observations of the outer layers of the solar convective zone, and theoretical understanding have demonstrated that this model is much more complicated than mlt assumes. during the years  , many studies were made in order to overcome the simplifications of mlt. among these, several non - local and non - instantaneous theories have been proposed. in the present paper,   results of a study of this subject are reported.
the efimov effect is the signature of a discrete scaling symmetry with scaling factor @xmath10 for short - range interactions.   it is associated with the existence of infinitely many trimer bound states that accumulate at the scattering threshold when the scattering length is tuned to the unitary limit. in heteronuclear systems with two species of atoms,   the scaling factor can be significantly reduced in the case of two heavy bosonic atoms of mass and one light atom of mass which makes it easier to observe multiple states. in this paper, we investigate the effect of the interspecies scattering length on the resonant enhancement of three - body recombination rates in an ultracold gas of cesium and lithium atoms by observing the resonance enhancement of the recombination rate caused by the trimers of identical bosons. as the scattering lengths are tuned to large compared to the range of the interaction using feshbach resonances, the resonants are more sensitive to the details of the inverse interaction range than the ones where the scattering distances are small.
in his first article on transfinite set - theory, georg cantor defined a set : von bestimmten wohlunterschieden objecten ( @xmath0 ) unserer anschauung oder unseres denkens ( welche die'elemente'von@xmath1 genannt werden ) zu einem ganzen ( @xcite, p.481 ).   the elements of this set are all the well - distinguished objects of our intuition or of our thinking ( which are called the'elements'of @x Math1 ) that we understand as a whole. in this article   i review the literature on the structure of minkowski space and discuss the various ways in which it has been studied over the last 100 years.
we review our model assumptions for the ism in early - type galaxies, as well as the possible sources of ionizing radiation in passively - evolving stellar populations.   we extend the work of @xcite to include a number of emission - line diagnostic tests for the presence of very hot sources, and those too cool to strongly ionize he ii. within the stellar population,   post - asymptotic giant branch stars ( pagbs ) remain the favoured candidate for powering the observed emission lines, but several other possible sources have also been suggested. in particular, we review the role of low - luminosity agn in the generation of the diffuse galactic background, and consider the possibility that the old stellar population may still provide a significant contribution to the local extreme - uv background.
noncommutative spacetime is a new notion of quantum spacetime with non - commuting directions.   it is related to string theory and quantum gravity. in this paper  , we study the possibility of nonassociative field theories on noncommutatively deformed spacetime using scalar @xmath6 field theory obtained from poincar invariant commutative associative algebras, where @x Math8 is a constant non - associative deformation parameter. since this product contains an infinite number of space - time derivatives, unitarity seems to be a non - trivial issue. however, we find that this field theory satisfies the cutkosky rule for the one - loop self - energy diagram by replacing the above product to avoid a divergence in the real part of the amplitude which diverges exponentially in minkowski spacetime, and by changing the square of momenta on the exponential to the forth power. also we show that the couplings of the scalar field theory are constant in general.
we present a new algorithm for identifying quasi - stationary patches of a time series by using the kolmogorov - smirnov ( ks ) statistic, which measures the maximal distance between the cumulative distributions of two samples, as estimate of the statistical discrepancy between segments.   the algorithm is based on a sliding pointer to detect the position that maximizes the ks statistic between the segments on both sides of the pointer and then checks the statistical significance ( at a chosen significance level ) of a potentially relevant cut at @xmath10 by comparison with the result that would be obtained if the series were random. in order to test whether two samples come from the same distribution, we use the entropy - based method, which is more fitted to symbolic sequences, while information is lost if discretizing a real valued series by means of thresholds. here  , we introduce a fully non - parametric version of the algorithm, named ks - segmentation, which takes advantage of the fact that it does not need to specify the common distribution of the two samples or the number of points in the series.
the pamela collaboration has recently published measurements of the cosmic - ray positron fraction performed with unprecedented accuracy.   these measurements have not only confirmed a significant deviation with respect to the expectations from a purely secondary component, but have also provided evidence for a very sharp rise of the spectrum at energies 7  100 gev. in view of the new results,   it is important to study whether the scenario of decaying dark matter is consistent with the energy spectrum measured by pamelae and what constraints the new data impose on the nature of decaying light. in order to keep the analysis as model - independent as possible  , we will analyze the cases that the dark matter particle is either a fermion or a scalar, and we will compute the predictions for the positron fractions for various decay channels and different dark matter masses and lifetimes.we find that the decay of dark matter gravitinos produces a flux of gamma rays, positrons, antiprotons and neutrinos which contribute to the total fluxes received at the earth. however, the astrophysical uncertainties in the determination of the secondary positron component are still large and nearby astrophysical sources such as pulsars might produce sizable positron fluxes in
we present a numerical simulation of the nonlinear elasticity of a semiflexible network of filaments and fibers.   the model is based on the worm - like chain model, which is well known for its ability to accurately describe the force - extension relationship of a single filament, as well as the magnitude of transverse fluctuations. in this work, we show that the same approach can also be applied to a crosslinked network of semiflexible filaments or fibers, where the main scaling features of the network's nonlinear mechanical response are determined by the single filament properties. using the obtained shear stress data of different filament networks, we find that the most appropriate interpolation formula for the full - extension filament relationship is @xmath6^{1/p } / a^{2/p}$, which captures the generic stress - stiffening effect originating from the characteristic divergence of the force- and strain - extension curve of an individual filament.
gamma - ray burst ( grb ) sources are rare and hence require continuous monitoring of large areas of the sky.   the detection of afterglows in the @xmath9-ray, optical and radio bands has made it possible to search for grb sources at longer wavelengths than previously attempted. here   we show that the rate of radio afterglow emission from a grb source can be boosted by up to ~2.5 orders of magnitude relative to the measured rate of grb emission using relativistic beaming with a lorentz factor of@xmath10. 	 this is because the radiation observed at a given time originates from a conical section of the fireball, and so the minimum solid angle into which the radiation could be focused increases with time. since the total energy associated with an explosion is proportional to @x Math10, the determination of @x math10 is of crucial importance for identifying the likely astrophysical origin of grbs.    the most likely origin of the gamma - ray bursts is binary coalescence of compact stars or failed supernovae, but there is also the possibility that some sources might be faint for geometric or physical reasons, e.g
the raman spectra of lead sulfide ( pbs ) grown as an n- or p - type semiconductor with carrier concentrations as low as @xmath1 were investigated using a kr@xmath13-ion laser.   the spectra are dominated by a band centered at around @x Math0 and a somewhat narrower peak at @x math4.    the frequency of the @x maths0 band anomalously increases with increasing temperatures, a fact that suggests interaction of each of the two phonons responsible for this band with a set of two phonon at lower frequencies.. the dependence of the temperature dependence of these two raman bands on the isotopic mass of sulfur, however, is normal and suggests that the corresponding eigenvectors are sulfur dominated. in order to complete the assignment of the observed raman structures, we have calculated the phonon dispersion relations of pbs based on an _ ab initio _ lda electronic band structure@xcite. using these dispersion Relations, which are rather close to the few points measured with inelastic neutron scattering ( ins ),   we have also calculated the density of two phon states for both sums and differences of two
we report here on the discovery of a very low - mass companion orbiting the brown dwarf candidate chah@xmath28, which was detected within the course of an rv survey for ( planetary and brown dwarf ( bd ) companions to very young bd / vlms in the chamaeleoni star forming region.   the radial velocity ( rv ) variations of the companion were measured by the echelle spectrograph uves at the vlt 8.2 m telescope at a spectral resolution of 40000 in the red optical wavelength regime with a cross - correlation technique employing telluric lines for the wavelength calibration with an accuracy of the relative rvs between 30 and 500 m/s. as shown by the rv data, the rvs of chah#28 are significantly variable on timescales of years revealing the presence of an orbit solution with a mass function of 4.6 @xmath13, an orbital period of 1590d ( 4.4yr ), an eccentricity of 0.49, and an Rv semi - amplitude of 1.6kms@x Math3.    the mass of the planet can not be determined directly from a single -
we have recently shown that email networks can be used to infer informal communities of practice within organizations, as well as their hierarchical structure @xcite.   this observation has led to the interesting suggestion that these networks may be useful for the efficient management of human collective behavior. in this manuscript   we provide a more complete study of email networks by lifting most of the restrictions imposed on the analysis of email traffic from a university departmental server and analyzing them via standard network measures for which we expect antisocial behavior to differ from social. using a novel method we show that the number of users and links in our dataset is dominated by spam traffic, which displays quantitative graph theoretical and dynamical characteristics that are nontrivial but also reflect a certain type of antisocial behaviors that can be quantitatively characterized and contrasted to the general properties of other social networks.
the coupling between dynamical systems can give rise to a number of collective phenomena such as synchronization, phase locking, phase shifting, amplitude death, phase - flip, hysteresis, riddling and so on.   many studies have examined the effect of time  delay coupling on the nature of the collective dynamics, particularly since time   delay makes the systems effectively infinite dimensional. in the present work   we study time  delayed coupled hamiltonian systems and show that the coupling quenches the oscillatory dynamics to a fixed point, namely the amplitude death ( ad ). when the system is decaying to a point attractor, there is an abrupt transition in the relative phases of the transient motion leading to the phase flip transition. here, however, there are special values of the time delay when the coupling term effectively vanishes : the underlying ham Miltonian structure then becomes apparent.
the diffractive production of vector mesons and real photons is a process where the colliding particles scatter at very small angles and without any color flux in the final state.   this involves a propagator carrying the vacuum quantum numbers, called pomeron, and is described, in the soft regime, within the regge theory. since the first operation period in 1992, zeus and h1, the two experiments dedicated to the dis physics at the hera, observed that @xmath1 of lepton - proton dis events had a diffractive origin. here   we present the most recent results achieved at hera together with a short outlook to the future exclusive diffraction program at the lhc accelerator. an introduction to a new phenomenological model for the description of the vms and dvcs amplitudes in the framework of the regle theory will be also given.
we present a method of solving the continuity equation for the emitting particle distribution, together with the assumptions made.   we assume that the emission is produced by a distribution of relativistic electrons injected in a region of typical dimension @xmath3 embedded in a tangled magnetic field ( s@xmath4 ), at a rate @x math5 , and that the cooling time for the highest energy electron may well be shorter than @x maths1, even once the effect of doppler boosting and blueshift is accounted for. to explain the time lags observed in the hard and soft x   ray light curves, we apply our model to the bl lac object mkn 421, to show how it is possible, even in our simplified model, to account for the variations seen in the light curves.. the results are compared with those of recent studies of the variability behaviour of the blazars short time scales variability, especially in frequency bands around and above the peaks of blazar spectral energy distribution.
the polarization of the cosmic microwave background ( cmb ) radiation has been directly measured by dasi and wmap experiments.   we use the @xcite model to predict the number counts of extragalactic radio sources at cm and mm wavelengths, which are expected to be the dominant polarized foreground on small angular scales, and we find that the model predicts 1 source all over the sky at cm wavelengths for every 100,000 light - emitting diode ( lode ) in a sky area of 10.38sr at @xmath4 at flux densities@xmath51.0jy with an average offset of ~1.5 jy. at mm wavelengths only a fraction of the observed e  mode polarization is due to the dust emission, while the majority of the b  mode component is produced by the gravitational lensing induced by large scale structures.
large scale primordial magnetic fields have been observed in galaxies and clusters of galaxies with the coherence lengths up to 10100 kpc.   these fields play an important role in various astrophysical processes, including the formation of first structures, reionization of the universe, and the signal from redshifted hi line from the epoch of reionisation. here   we use cosmological weak lensing and the study of ly@xmath2 clouds in the redshift range @xmath5 to investigate the origin of these magnetic fields. using a semi - analytic approach, we simulate density fluctuation along the line of sight and estimate the contribution of matter perturbations induced by these fields to the effective opacity of the intergalactic magnetic field ( igm ) for this computed cloud distribution. as a result  , we find that the dense regions of the igm are more opaque than the relatively non - dense regions. at the same time, the dark matter power spectrum of the entire igm is dominated by the magnetic fields induced by the primordial cosmic magnetic fields which can be explained by the fact that they are generated by dynamo amplification of very tiny seed magnetic fields during the inflationary phase.
the radiation mechanisms of many high energy astrophysical objects are still an active issue since they often contain features which are not easily explained by the conventional synchrotron and inverse compton emissions.   recently, much attention has been paid to the radiation signatures from the turbulent electromagnetic fields. in this paper, we present a new method for reproducing the observed radiation spectra of a small scale turbulent magnetic field using a series of line - upped magnets. when the typical spatial scale of an eddy is smaller than the photon formation length ( pfl ) of the syn chrotron photons, the radiation spectrum of the turbulent field shows a sharp peak at the peak frequency, while the radiation of the wiggler device shows a broad spectrum with peak frequency at the beginning of the turbulence.. the results show that the intensity of the radiation from the turbulence depends on the critical distance between the magnet and the beaming cone, which is determined by the deflection angle of the object.
among various statistical quantities, there is a promising class of statistics which utilizes smoothed cosmic fields.   the smoothed field has less noisy property than the actual ( unsmoothed, or raw ) cosmic fields, such as galaxy distributions, temperature fluctuations of cosmic microwave background, shear fields of the gravitational lensing, and so forth. among them, the top - hat smoothing function, which is a function of smoothing length, is one of the most widely used statistics. in this review,   we discuss the recent developments of the perturbation theory in calculating the variance, the cumulants, and the density probability distribution function of these statistics, and their applications in cosmology.
accreting low mass x - ray binaries ( lmxbs ) have been divided into two groups based on their broadband spectral and timing properties.   the six currently - known @xmath0-sources are named for the three - branched shape they describe on a diagram of hard color versus soft color. here   we present extensive additional data from lmc  x2 in which the source convincingly traces out all three branches in its hardness - intensity and color - color diagrams, confirming its @x Math0-source identification.
the tree compatibility problem is a generalization of the supertree problem, in which two phylogenetic trees with partially overlapping taxon sets are given a set of input trees.   the question is whether there is a tree whose taxon set is the union of the taxon Set of the input trees, such that it exhibits not only the clusterings among the taxa, but also the ancestor / descendant relationships among taxa in the input Trees. here   we present a new algorithm for testing ancestral compatibility for trees with nested taxa using the @xmath2 supertree method. to test ancestral compatibility, we use the same input trees as in the original version of the tree Compatibility problem, but the internal nodes and some of their leaves may be labeled with higher - order taxa. by doing so, we show that the proposed algorithm is more efficient than the fastest previous algorithm for tests of ancestral compatibility.
the first beryllium detection in a star characterized by a metallicity well below one thousandth solar ( =@xmath03.3 ), the halo star g6412, is presented.   the new  ratio is compared to previous observational analyses in low met allicity stars and confronted with different theoretical suggestions.
we examine the effects of substructure in dark matter halos on the matter and weak lensing power spectra of high resolution @xmath6-body simulations.   we use the result of a high resolution simulation to quantify the changes in the power spectrum when we smooth out increasing amounts of substructures, and we incorporate substructure into the analytic halo model using a cosmological dark - matter - only simulation that contains a significant amount of subhalos. at this level  , we find that the substructure can contribute significantly to the nonlinear power spectrum because they typically constitute about 10% of the host mass. by smoothing out the subhalo particles within the virial radius of each host halo, we show that the strength of the change in the light - to - dark lensing convergence power spectrum is proportional to the size of the subsurface of the halo and the number of simulation particles in each halo. as the density structure of the dark matter increases, the magnitude of the shift in the softening power spectrum becomes smaller. for small subhalo - containing halos,   the effect is more pronounced than for large sub Halos. with increasing densities
the present article is a continuation of our works @xcite.   we have found a way to derive a quantum analogue of the lax matrix of the trigonometric ruijsenaars - schneider model by means of the cherednik operators. for the macdonald polynomials in the variables @xmath10, we introduce the analogues of non - commuting heckman operators acting on the rational functions of @x Math10 and are denoted by @x math11 and @x maths12, respectively.we also reformulate theorem  by introducing a certain matrix @xMath13 with operator entries acting on both the rational and the logarithmic functions of the variables@xmath9 that is closely related to the classical lax matrices of the modulus- and poisson bracket - based hamiltonian model @xaite. using this matrix, we show that the jack symmetric functions can be regarded as eigenfunctions of the limits of the power sums of some commutation operators at @x{\math1}=0.5 mm, which act on the poisson brackets of the monte carlo poisson space of symmetric polynomial
x - ray bursters are a new class of low luminosity hard x - ray emitters, which have been discovered by means of the _ bepposax_/wfc ( jager et al.   1997 ) wide field cameras. in this work   i report about observations of a sample of these new bursters and discuss their broad band spectral properties, as obtained from target - of - opportunity observations by the narrow field instruments ( nfi ) on board _   beppoax_. this is a set of co - aligned telescopes capable of efficient, continuos spectral coverage in the band 0.1 - 220  kev. among these objects, interesting is the discovery of burst emission from gs  1826 - 238, showing that this source, previously considered as a transient black hole candidate ( bhc ) is instead a persistent, low lumosity source with nearly periodic, extremely regular bursting behaviour.    the burst peak fluxes of this source are estimated to be up to 1.5  km2/year and the burst time profiles show a double - peaked structure, each peak being associated with the expansion and contraction phases.
the phase - space formulation of quantum mechanics has received a renewed attention in the last decades because it allows to employ notions and tools of classical physics in the quantum realm.   the central object in this approach is the wigner s function, which is merely a phase -space representation of the density matrix. in contact with the surrounding medium, the ( open ) system experiences dissipation, fluctuations, and decoherence. in this paper  , we present a new method to solve the fokker  planck equations of systems with few degrees of freedom using the continued - fraction method. by truncating the hierarchy of equations at a low level,   we obtain an approximate solution for the equation for the system with a few degree of freedom coupled to its environment, or bath, which under appropriate conditions can behave quantum mechanically.
the momentum space lattice method for the study of continuum qed on the torus is discussed.   it is shown that the method is computationally cheap and has two main advantages : 1 ) the coupling of the fermions to the gauge fields is non - compact and 2 ) there is no fermion doubling. in the case of qed3 and qed4,   the method also has two potential problems, which we should discuss here.
the main aim of this symposium was to shed some light on the formation of single degenerate white dwarfs ( sneia ).   it is widely acknowledged that sneia are generated by thermonuclear disruptions of carbon - oxygen- ( co- ) white dwarf ( wd ) cores. according to the most commonly accepted view, a wd must either accrete enough matter from its companion or it must merge with its companion. in the case of stable roche lobe overflow ( rlof ),   the donor does not need to be a hydrogen - rich main sequence ( ms ) or giant - like star. during quiescence, supersoft x - ray sources ( ssss ) undergo stable hydrogen burning on the wd and they can accumulate @xmath3 m@xmath1 of material during their nuclear burning phase. if these wds can accumulate ~3 m/yr of material over a period of @x Math2 years, they could end up as sneia.. however, the existence of a double degenerate ( dd ) channel remains controversial. here  , we discuss the pros and cons of the two main channels both from observational and theoretical points of view.
the scale dependence of gravitational couplings has been extensively studied in the context of exact renormalization group ( erg ) equations.   this paper is a complementary contribution to the existing studies on erg improved black hole solutions by taking the classical solutions and replacing the newtons " constant " and the cosmological constant in those solutions. as starting point   we will take the improved equations of motions which contain scale depending couplings @xmath0 and@xmath1 which are a priory undetermined. using the most symmetrically possible metrical ansatz we will then ask for which functional form of those couplings it is possible to solve those equations of motion with the best symmetry possible. since both couplings of the present solution are functions of the radial scale, the corresponding adimensional couplings   can be combined in a coupling flow which is shown to be an induced flow with an ultra violet fixed point for each of the couplings. finally, the anomalous dimensions of the induced couplings and the product of couplings are discussed and compared to the findings in the erg approach.
we investigate the ferroelectric phase transition behavior of batio@xmath0, a prototypical example of the perovskite oxides, using a first - principles approach.   we construct an effective hamiltonian to describe the important degrees of freedom of the system,@xcite and determine all the parameters of this model from high - accuracy _ ab - initio _ local density approximation ( lda ) calculations,@xaite and carry out monte carlo simulations to determine the phase transformation behavior of the resulting system. in particular, we report the calculated transition temperatures, order parameters, and phase diagram, as well as the phase diagram of the tetragonal phase transition for @xcite.
a rigorous connection between equilibrated two - dimensional foams and the sectional multiplicative partition ( smvp ) is established.   this connection provides a set of fundamental degrees of freedom for the foam ( the source s locations in space ), and therefore constitutes a step towards the theoretical understanding of its dynamical properties. given an arbitrary ef, it is always possible to find sources in space such that a smvp with respect to them exactly gives this foam.
the left - right supersymmetric model ( lusy ) proposes a solution to the charge - parity ( cp ) violation problem in the standard model ( sm ).   it enlarges the gauge sector of the theory from left - handed to right - handed symmetry and allows for right - sided gauginos in addition to several higgsinos. in this work  , we investigate the effects of these new phases on the masses, production, and decay rates of charginos in the electroweak chargino sector. using a general unconstrained model, assuming arbitrary phases, we find the combination of angles that would affect the phenomenology, as well as presenting experimentally testable signals from the chargino sectors. by increasing the number of phases in the neutralino sector,   we show that the rate of chargino production increases with increasing the angle of the cp - odds at the scale of @xmath2, and that the effect is more pronounced in the quark and lepton sectors, where the scalar masses can be large. however, the effect of the new phases is not as pronounced in other sectors, such as the neutraline sector, where they are expected to be small.
the oceanpal project at starlab focuses on the development of technologies for operational in - situ or low - altitude water surface monitoring using global navigation satellite reflections ( gnss - r ).   we report here an experimental campaign dedicated to sea - state monitoring using coastal gps reflections as gathered and processed by the oceanpal instrument. a geophysical analysis based on the correlation time of the reflected field   is then discussed.
with the discovery of the higgs boson at the lhc, an important step towards a complete identification of the structure of the mechanism of mass generation in the electroweak theory has been taken.   however, it is clear that one needs suitable extensions of the current version of the standard model ( sm ) in order to solve some important theoretical and phenomenological issues which do not find an answer within the same model. among them   is the issue concerning the instability of the scalar potential of the sm under the perturbative renormalization group evolution up to the planck scale, which has been viewed as one of its unappealing features. here  , we present a new analysis of the spectra of the polynomials of the spacetime of the top quark and the higgens boson, for large values of the field, larger than the maximum value of the effective potential, which are obtained from the measurement of the highest - energy higgs mass at zero and at finite temperature, using the raman spectroscopy of the quantum field theory and cosmological context.. the results show that the modulus of the q = 0.1/0.2
charge qubits based on single donors in silicon have been the subject of much research in recent years from both theorists and experimentalists alike.   while a number of experiments have probed into the physics of single donors @xcite, many others have concentrated on precision control and fabrication of qubit systems based on individual donors. as experiments are getting closer to fabricating a donor based charge qubit system, it is important to develop a detailed theoretical model that analyzes the various aspects of qu bit control and design space, and predicts accurate numbers for quantities likely to be measured by experiments. in this paper  , we employ atomistic tight - binding theory with a model for p impurity in si that accurately captures the basic single donor physics such as the valley - orbit split donor spectrum. by solving the full Tight - binding hamiltonian for realistic systems of about 3 million atoms, we are able to obtain any number of states of the @xmath0 spectrum. using an electrostatic gate potential from a commercial poisson solver, we show that the tunnel coupling between the two lowest eigen states of each donor nucleus can be controlled smoothly by constant electric fields for both homo and hetero polar donor species.
the microstructure of the hydrated clusters of sulfonate head groups in a proton - conducting polymer electrolyte membrane ( pem ) is studied by using a simple dipolar head group model for ionomer side chains.   we show that the dipole - dipole correlations strongly depend on the molar fraction of acidic groups and dielectric permittivity of the membrane, and that globular micelles formed in the case of zero dipole moment evolve to percolated cluster structures for a non - zero dipoles of head groups when an artificial attraction between the end groups of side chains is introduced. accounting for the dipolenic moment of the head groups   thus changes the conformational structure of clusters from a gierke model of spherical aggregations to a gebel model of elongated aggregations.
a resonant cavity enhanced photodetector ( rcepd ) based on the narrow gap lead salt semiconductors operating at a wavelength of @xmath3 = 3.6@xmath0 m has been fabricated.   the structure consists of a two - period bragg interference mirror consisting of pb@x Math3/4+/4 + / eute layer pairs acting as bottom mirror of the detector sample and a bragg mirror with a metallic mirror as second mirror. in the cavity,   a thin absorbing layer is placed in a vertical optical cavity which is covered by a sio@x math1 layer serving as an insulator. for detection of trace gas molecules in air or in other carrier gases, the detector can be tuned to the molecule absorption line using a narrow band emitter and a broadband detector or a broadband source such as a glowbar and a detector with a small spectral bandwidth. this yields advantages compared to conventional detectors because ( a ) the narrow detection wavelength of interest can be tunable by the cavity length and ( b ) the quantum efficiency is enhanced due to the standing wave effect caused by the cavities.
the proliferation of mobile devices and the surge of a myriad of multimedia applications has resulted in an exponential growth of the mobile data traffic. in this context, wireless caching has emerged as a powerful technique to overcome the backhaul bottleneck, by reducing the back haul rate and the delay in retrieving content from the network.   the key idea is to store popular content closer to the end users. in @xcite,   a novel system architecture named _  femtocaching _ was proposed which consists of deploying a number of small base stations ( bss ) with large storage capacity, in which content is stored during periods of offpeak traffic. here  , we consider a similar cellular network scenario as the one in @excite, where content is encoded using a maximum distance separable ( mds ) code to small bss and stored in several mobile devices using an erasure correcting code. for the scenario where content can be stored directly in the mobile devices, the repairing of the lost data when a device storing data leaves the network was considered. assuming instantaneous repair, the communication cost of data download and repair was investigated. in both scenarios, the overall communication cost entailed by storing content using mds codes, regenerating codes
the evolution of accretion discs is determined by the outward transport of angular momentum, which induces infall of matter toward the orbital center. in magnetized discs   this mechanism is triggered by a linear axisymmetric destabilization, the magnetorotational instability.   it is generally assumed that the accretion rate depends on an effective viscosity. in hydrodynamic keplerian discs, instead, the presence of an efficient outward transport and the interaction between the vertical shear and convective instabilities are still an open question. in the present study   we show that, while non - axisy mmetric perturbations eventually decay, they experience transient exponential growths which are indistinguishable from a genuine instability. using the shearing sheet approximation, we find that the direction of the vertical convection induced angular momentum transport changes depending on the sign of the product of vertical and radial wavenumbers ( i.e. positive for@xmath7 or negative for @xmath8, where @x Math9 is the local verticalShear ).    thermal diffusion has a stabilizing influence on the convective instability, specially for short wavelengths.
the equilibrium statistical mechanics of infinite ( bulk ) media, conductors and dielectrics, fully coupled to the radiated electromagnetic field is studied.   the crucial problem of statistical analysis of such models is to determine how fluctuations of various statistical quantities, like charge and current densities, scalar and vector potentials, electric and magnetic fields, etc., around their mean values are correlated in space and time. a special attention is devoted to the behavior of correlation functions at asymptotically large distances and to the so - called sum rules, which fix the values of certain moments of the correlation functions.
the oss mission relies on the gravity advances package @xcite for its fundamental physics objectives.   it is an instrument composed of an electrostatic accelerometer called microstar, based on onera expertise in the field of accelerometry and gravimetry with champ, grace, and goce missions, and a rotating platform, called bias rejection system  ( brs ). in orbit technology  , this instrument aims at measuring the non - gravitational acceleration of the spacecraft with a precision compatible with the european space agency ( esa ) requirement and with no bias.the measurements made by microstar or any other electro static accelerometer always include an intrinsic bias which may vary with time or temperature. to remove properly the bias of micro star,   the bias rejected system rotates the accelerometer following a carefully designed periodical pattern. in terms of measurement noise, this operation selects the noise of microstar around the modulation frequency. after post - processing and for a modulation period of @xmath1  min, it allows making absolute measurements with a white noise whose power spectrum density ( psd ) level is @x Math2  m.s@xmath0.hz@x math3 with a cut -
open - loop decoupling strategies have been proposed for the protection of quantum systems against decoherence.   these open - loop control schemes are typically implemented via strong and rapid pulses known as " bang - bang " ( bb ) controls. in this paper   we discuss the last of the above - mentioned applications  polarization qubits in a ring cavity  @xcite and provide an analytical explanation of the results. by means of suitably oriented waveplates,   bb controls can be implemented along the photon path, i.e., along the pulse path, rather than in time, which is the most common mode of transmission in quantum communication protocols. to test the effectiveness of these techniques, we demonstrate that they can be applied to the evolution of an optical pulse traveling back - and - forth between two points in space, e.g., on a two - way optical channel in a plane - parallel cavity and in a circular ring cavity. using different waveplates in the cavity  , we show that the decay of the polarization state of the pulse in the ring cavity is significantly inhibited when the pulse is impulsive, whereas it is not affected by the presence of appropriate waveplates.
non - collinear magnetoresistance ( ncmr ) is a general effect of spin mixing in the local environment, which arises from electron hopping between atoms with canted magnetic moments.   it has been observed experimentally for a pdfe bilayer of ir(111 ) and @xcite, where the electronic band structure of the pd layer is different for collinears versus non - collinsear spin configurations. here   we investigate the influence of the spin on the tunneling magnetores resistance ( tmr ) of the bilayer by using scanning tunneling microscopy ( stm ) measurements of the differential conductance signal at a non -collinear ( nc ) or ferromagnetic ( fm ) position of thespin texture. as a result  , we find that the mr changes are due to a spin mixing of states due to spin - orbit coupling ( soc ), which is more pronounced for skyrmions than for ferromagnetic ones. because of its spatial resolution,   stm measurements can be used to unravel the changes of the vacuum local density of states ( ldos ) of a domain wall : the difference between the center of
electron transfer ( et ) is a very important process in biology, chemistry and physics.   the purpose of the present investigation is to present a simple, analytically solvable model based on the density matrix formalism @xcite and apply it to a porphyrin - quinone complex which is taken as a model system for the bacterial photosynthetic reaction center by propagating a density matrix ( dm ) in liouville space using the same formalism as the generalized stochastic liouveville equation ( gsle ) model for exciton transfer from the haken - strobl - reineker ( hsr ) model@xcite.the model is solved by applying the master equation of the dm formalism to the model system and solving the differential equations for the einstein coefficients and the relaxation coefficients. at the interface between the two states of the complex   there is a high degree of agreement between the results obtained by the path integral method and those obtained by perturbation theory and the semiclassical marcus theory ; however, the latter is more accurate and more expensive than the former.
interstellar turbulence and its implications were commonly discussed in the 1950s, but without the range of observations that are available today, the theory of the interstellar medium ( ism ) drifted toward increasingly detailed models based largely on a preference for thermal and dynamical equilibria.   one of the most important developments in the field of interstellar gas dynamics during the last half - century was the renewed perception that most processes and structures are strongly affected by turbulence. here   we summarize observations of abundance variations in stars and gas, and we review recent theoretical work on interstellar turbulent mixing.
tolman - oppenheimer - volkoff ( tov ) equation derived from the einstein s field equation gives the pressure gradient of neutron stars.   our aim is to establish a modified tov equation which is the prime structure equation for compact stars. in  2   we will show the derivation of the new equation to replace the tov equations, starting with the standard metric for a spherically symmetric star and the consecutive use of einsteins field equation in the case of accelerating universe. then we show the numerical calculation of maximum mass of neutron Stars by plotting the mass - radius relation.
the thermal conductivity of single - walled boron nitride nanotubes ( swbnt ) is investigated by the boundary and three - phonon scattering calculations.   the thermal conductivities of swbns are dominated by the flexure modes, which can be clearly interpreted with the help of the helical quantum numbers. in this paper, we calculate all required physical quantities from the tersoff plus universal force field out - of - plane potential for the interaction potential in sp2 bn sheet using the selection rules derived from the symmetry selection rules for the three-phonon scattering process. as a result  , we find that the thermalconductivity of Swbnt shows diverging behavior with length as@xmath2, where the exponent @xmath7 decreases exponentially with the increase of temperature @x Math8.. the thermal transport in swb didnt show any significant change with increasing temperature.
wireless networks are ubiquitous and are on their way to become even more prevalent, e.g. with the advent of internet - of - things.   wireless communication is, however, particularly challenging to model algorithmically. in two crucial interrelated aspects, wireless networks on the ground differ from models typically assumed in algorithmic studies : when is a transmission successfully decoded, as a function of the environment and the interference from other transmissions ; and when is the transmission successful?   we aim in this paper to address core information dissemination problems in dynamic distributed networks, under very weak assumptions on the communication. to this end  , we propose a communication model with significant flexibility that allows for adversarial control, generalizing essentially all known analytic wireless models ( including quasi - unit disc graphs, unit - ball graphs, bounded - independence graphs, @xmath0-hop extensions, and sinr ). by allowing for more general interference relationships than treated before,   the model can be extended to include both edge changes and node insertions / deletions.
we consider the incorporation into fundamental physics of local conformal symmetry ( or weyl - symmetry ) : that is, classical local scaling symmetry in an action that includes the standard model coupled to gravity.   a new result of our approach @xcite-@xcite is that using conformal symmetry we are able to solve the classical frw equations across big crunch - big bang transitions, thus obtaining the _ full set of geodesically complete cosmological solutions _ of our conformal standard model. this follows from the new properties of the standard theory whose couplings to gravity include all patches of field space that are required for geodesic completeness of all cosmsological solutions for all times and any set of initial conditions.
we show that periodic perturbations that break the time - reversal invariance ( tri ) of the optical lattice can change not only the sign of the tunneling amplitudes, but also their complex values.   we focus on superfluid fermions in the bardeen - cooper - schriffer regime with broken tri and show that typically a pairing function for @xmath0-wave interactions acquires a complex phase which may be controlled by the tri breaking mechanism considered in the present paper.
the availability of large amounts of data has been accompanied by a systematic study of the empirical properties of price time series.   this led to the identification of relatively well defined properties, the " stylized facts " ( sf ), reasonably common to all markets, which are beyond the simple random walk ( rw ) dynamics. in this paper   we introduce a minimal model with the objective of reproducing the sf with the simplest possible elements, in order to trace precisely the origin and the nature of the sfs. for the first time   it is shown that the self - organization of the market is a general characteristic of several abm, as for example the lux - marchesi model  . the competition between stabilizing and destabilizing agents, corresponding usually to fundamentalists and chartists, is believed to be a realistic and generic property of the markets. however, many models of this type have been introduced which often do not permit to clearly point out which aspect of the model is really responsible for the Sf and to which extend these results can be considered as an explanation of the observed empirical evidences. in particular, the complexity of these models often does not permit the analysis of the specific origin of
we report the growth of zno films on sapphire ( 0001)-oriented by pulsed laser deposition ( pld ), using a zn metal target.   the effect of the deposition parameters on the degree of epitaxy and defects density of laser - ablated zno thin films is qualitatively discussed in this paper. for the first time  , we have used x - ray diffraction ( xrd ) to study the structural properties of the zno nanocrystalline films obtained by pld. as a result, the results show that the temperature and oxygen pressure can be systematically varied from 400 to 750@xmath6 and 0.03 to 0.2 torr of o@x Math0.2, respectively. at the end of the application, the films are cooled to room temperature ( 20@x math7 ) under 225 torr or less of oxygen. after cooling the films, the strain of the films has been determined by sin@x maths20 technique. also, the surface roughness and the density of defects have been measured by scanning electron microscopy ( sem ) and xrd.
the gas mass and its mass fraction in high redshift galaxies are key parameters to trace galaxy evolution.   we aim to derive the gas and dust masses independently to constrain the gas - to - dust ratio in massive star - forming galaxies in the main sequence at @xmath2 using co(@xmath16 ) luminosity and co- to - h@x Math17 conversion factor ( @x math18 ). to estimate the dust mass, we select galaxies which are detected with _   spitzer_/mips in 24 @xMath3 and   herschel_/spire in 250 @x maths3 and 350 @x mathematics3. for the molecular gas mass fraction, we choose galaxies with solar metallicity derived from an optical emission line ratio method ( e.g., n2 method : @xcite ).    we find that the gas mass fractions in these galaxies are about ten times larger than those in the present - day massive spiral galaxies ; however, the dust masses are about twice as large as those found in the current - daymassive spiral galaxies. by combining the results of our study with the results from theoretical calculations, we predict a redshift evolution of the
we investigate the effects of low values of the cosmological constant @xmath8, as allowed by current data, on the fit of models with and without dark energy ( de ) coupling.   we consider two different models, set by similar values of cosmology parameters, without and with coupling. starting from these models, we evaluate the expected errors on cosmologic parameters, as obtained when data concern just cmb anisotropy and polarization or include tomographic weak lensing or include strong lensing. in the latter case, we use a fisher matrix technique to compare the errors of model - based predictions with those of experimentally observed data. for both models,   the results show that the errors are not consistent with the observed data, except for the redshift dependence of the growth factor, which can be reproduced through a suitable redshift dependent of the de density and state parameter.
scale - free structures are intriguing because they suggest dynamic principles that are universally applicable to the simon model @xcite.   we elaborate on another class of self - organization models, based on the  aggregation with injection   scenario from the social sciences ( soc ) model, which is interpreted as a merging - and - creation process. in this model,   two elements are chosen randomly and then merged together, each characterized by a scalar, and the resulting power - law exponent for the distribution of scalars among the elements is determined by a non - equilibrium bottom up process where the number of elements in the system is constant at steady state. using numerical simulations, we show that the scaling of the power - Law exponent is independent of the size of the growing element and depends on the existence of a single growing, large element. when the average of all the other elements is small, the power-law exponent is always equal to or close to the same asymptotic value, whereas when it is large, it is always higher than the sum of the remaining elements.. the results are consistent with the hypothesis that the growth of the system can be explained by a mechanism which is quite different from the
we have implemented techniques for calculating the branch cuts of expressions inherited by functions acting on non - trivial arguments, and extended this to calculate the cuts of expression and relations of such functions.   we have applied these techniques to the problem of calculating the branches of expressions in a single complex variable. when defining multi - valued functions, most computer algebra software ( and indeed most users ) tend to work with them by defining their single - valued counterparts which will have discontinuities over the cut definitions. as a result,   relations true for the multivalued functions may no longer be true for their single valued counterparts and hence understanding the branchCuts of the relations becomes essential for working with them efficiently.
star clusters in local group galaxies comprise a wide range of roughly coeval stellar agglomerates ranging from globular clusters to associations, from very metal - poor objects to clusters with solar and higher metallicity, and from ancient populations to embedded young clusters.   we review the current knowledge of the formation of star clusters in the local group and discuss how they may have been formed.
the radio - frequency set @xcite ( rf - set ) is a new type of single - electron transistor that uses the microwave reflection from a tank circuit containing the set to measure the effective set resistance and affects the intensity and the phase of the reflected ( or transmitted ) wave that is later sensed by either homodyne detection or simple rectification ( to separate incoming and reflected waves a directional coupler can be used ).   the high operation frequency of the rf-set makes it easily possible to avoid the 1/@xmath16 noise limitation of the set sensitivity which is typically dominant at frequencies @xmath17, and so work in the region of the shot noise limited sensitivity.the present paper reviews the current state of the art with respect to the use of the Rf -Set for the readout of charge qubits.
the effect of a circularly polarized electromagnetic field ( cpef ) on the energy band structure of the dirac system in graphene gapped by a spin - orbit interaction ( soi ) or by a polar substrate is discussed.   the effect of the spin - orbital interaction on the gap between the valence and conduction bands near the fermi level is compared with that induced by the symmetry breaking sub - lattice symmetry breaking ( ssb ) by an underlying polar substrate in epitaxial graphene, and the effects of the soi and the ssb on the plasmon excitations in single and multilayer graphene are also discussed.
the millisecond quasi - periodic oscillations ( qpos ) in the x - ray emission from accreting neutron stars are most likely associated with orbital motion near the neutron star, and, thus, potentially offer a new probe of accretion flows and strong gravitational fields near neutron stars in x -ray binaries.   the key to exploiting the khz qpos as probes of strong gravity is to understand the qpos at a sufficient level so that those aspects of the qpo which depend on the properties of the gravitational field can be separated from the aspects which depend upon details of the accretion physics. here  , i present some initial steps of attempts to understanding the key quantitative features of the Qpos, such as the centroid frequency, and their relation to the propertiesof the accreted matter.
the dice2013r model of the global climate and carbon cycle is a powerful tool for understanding the dynamics of global economic processes.   it has been widely used to study the effects of global warming, climate change, and the global carbon cycle on the global economy. here   we present a new version of the dice2013 r model that uses the casadi framework for algorithmic differentiation and numeric optimization in conjunction with matlab to model the global greenhouse gas emissions mitigation rate ( gtco ) and the savings rate ( srs ) as well as the global capital cycle over five time steps from 2010 to 2013. using this model  , we show that the Gtco and srs can be modelled in terms of a set of endogenous state variables and several exogenous, time - varying terms such as population and total factor productivity. by combining the two frameworks, we have developed a simple and robust method to derive the full dynamics of the atmospheric and oceanic temperatures, carbon cycle, and global capital dynamics under different emissions mitigation rates and savings rates.
@xcite and @xcite have reported a sudden drop of the fluxes of the heliospheric energetic particles and a substantial increase of the galactic cosmic ray ( gcr ) fluxes in august 2013 at theheliocentric distance of @xmath1122 au.   such a behavior of the energetic particle fluxes could be treated as crossing of the Heliopause by voyager  1 ( v1 ). here   we assume that the crossing occurred at 122 au and estimate how the effect of thermal conduction influences the plasma flow in the inner heliosheath and the positions of the termination shock and heliopause. using kinetic - hydrodynamic approach we consider the interaction of the solar wind with the local interstellar medium using the ideal magneto-hydrodynamic ( mhd ) equations, while the neutral component is described using the kinetic equation. for each of the parameters we use finite - volume high - order godunov scheme that includes 3d adaptive moving grid with discontinuities capturing and fitting capabilities, harten - lax - van leer discontinuity ( hlld ) mhd riemann solver and chakravarthy - osher tvd procedure.
we study the effects of meson exchange terms on the two - body point - coupling terms of the rmf model.   we find that the exchange effect is not absorbed effectively in the coupling constants of the model due to the fitting procedure, but that it is more effective when the exchange terms are explicitly treated explicitly. by using a general form of effective field theory,   this effect is reduced to local currents and densities as compared to an effective hartree theory.
the fisher process is a generic description of the invasion of a stable phase into an unstable region.   it is applicable to wide range of phenomena, ranging from genetics ( the original context of fisher work, proliferation of a favored mutation or gene ) to population dynamics, chemical reactions in unstirred reactors, hydrodynamic instabilities, invasion of normal states by superconducting front, spinodal decomposition and many other branches of natural sciences. here   we review the recent work on spatial segregation induced by competition for common resource in the vegetation - water system.
the rapid x - ray variability of accreting black holes suggests that in many of these sources x - rays are emitted very close to the last stable orbit of an accretion disc presumed to power the emission. at the same time, most of the power emitted by agn ( e.g., *????   * ) seems to come out in the optical / uv band, implying that the disc is relatively cold all the way to the final stable orbit.   x -rays are thus emitted in a physical proximity to the cold disc and should produce fluorescent emission lines and the continuum " reflection component  from agn @xcite. due to a high fluorescent yield and abundance of fe among heavy elements in the interstellar medium, the strongest fluorescent line   is expected to be the fe k@xmath0  line which is usually the strongest in the time - averaged observed spectra of agn. however, there is a considerable number of observations of Agn with broad but relativistically shifted fe k=0  lines in snapshot spectra, which can not be explained in terms of photo - ionised x -ray reflection models. here   we discuss the possible explanations for
the determination of the binding energy of nuclei starting from realistic @xmath1 potentials is one of the subjects which has received permanent attention from the early days when the brueckner - bethe - goldstone ( bbg ) equation introduced methods to overcome the strong repulsion of the nuclear forces at short distances.   a common feature of these approaches is that they start from the realistic nucleon nucleon interaction, obtained from fits to nn data and deuteron data. in this paper   we present a new picture of the @x Math0-meson exchange within chiral unitary approaches which allow to improve the description of the correlated two pion exchange @xcite, as an alternative to the conventional@xmath0- meson exchange interaction.. the changes obtained are moderate, thanks to the simultaneous consideration of these nuclear medium effects and the consideration of short range correlations not only in the pion selfenergy but also in the vertex functions appearing in the model.
bd+48 740 ( tyc 3304901 ) is a lithium - overabundant red giant ( rg ) star.   it is one of the targets of the penn state toru planet search ( ptps ), which is devoted to the detection and characterization of planetary systems around stars more evolved than the sun. in this paper  , we report the discovery of a planet in a highly eccentric, long - period orbit around a solar - type rg star. using the hobby eberly telescope ( het ) @xcite, we have measured the relative relative velocities ( rvs ) of the star at 15 epochs over 2229 days using the standard i@xmath11 cell calibration technique. with the estimated amplitude of solar  type oscillations @xmath6 8  ms@x Math12 and the average rv uncertainty of 5.6 m   s@x maths12, the observed rv amplitude was @x math13 times larger than the expected observational uncertainties. according to the standard evolution theory,   the star should have a lithium abundance of about 1.5 when it leaves the main sequence and becomes a red giant. by means of the high resolution
the thermodynamic properties of matter under extreme conditions of temperature and density are required for a correct description of the mechanical and thermal properties of many dense astrophysical bodies, including giant planets, low - mass stars ( i.e., stars smaller than the sun ), and so - called compact stars ( white and brown dwarfs and neutron stars ).   these objects are composed dominantly of ion - electron plasmas, where ions are strongly correlated and electrons are strongly or partially degenerate : classical coulomb coupling parameter @xmath0 is large and electron density parameter@xmath1 is less than unity. in this short review,   we focus on the two extremes of this range of astrophysical objects in terms of matter density : jovian planets and neutron Stars. as will be shown in the next sections, modern experiments and observations provide stringent constraints on the thermodynamics properties of dense matter under the physical conditions characteristic of these objects.
grid computing for the high energy and nuclear physics communities will need to deal with thousands of users and hundreds of computing facilities in the near future.   traditional computing models require that each user must register individually with each computing facility, but this model will not scale as the number of users increases. we have developed a user account management system and tools to allow sites to keep track of users using a user management model that is based on trustable, trusted and auditable user information. these tools will be compatible with whatever virtual organization ( vo ) management tools are adopted for the large hadron collider computing grid project ( lcg ), although we have some requirements to put on those tools.
we derive a criterion for the phase - space nonclassicality of at least one of the input states to a beam splitter ( bs ) to guarantee the entanglement of the output modes, regardless of the other input state.   remarkably, our criterion immediately removes any assumptions about the purity or the separability of the inputs. in this contribution  , we prove that a single - photon state of sufficient purity generates entangler from any state, e.g. an arbitrarily high temperature thermal state, upon incidence on any bs. also re - examine entanglements detection stage and show that entangement can be imprinted onto a single-mode in the form of phase -space negativities. in other words, detecting negativity of marginal phase - spaces functions at the output of a bs using homodyne detection is very simple.
random matrix theory is a discipline with wide range of physical applications and plenty of beautiful mathematical results.   the problem of determining the spectrum of the density of states in a random sparse matrix is one of the most difficult problems in random matrix theory due to the fact that real physical systems are embedded in three - dimensional euclidean space. here   we review the recent advances in the field, which have been made in the last few years.
we derive a fully analytic form for the linear non - barotropic corotation torques in the protoplanetary disk.   we apply this form to the effect of stellar illumination on the eccentricity of migrating planets, and show that the first - order corotation resonances can be used to excite eccentricity in migrating planets while the non - linear horseshoe torques can damp it in a barotropic disk. as a gap clearing planet   perturbs the disk, lindblad resonances excite the planet s eccentricity while non co - orbital corotation Torques damp its eccentricity. here  , we apply these results to eccentricity excitation in disks in which the gap formed by a migrating planet is heated by stellar irradiation. using the new formulae, we find that the main effect of the two types of resonances is to damp eccentricity for small planets, while the second effect is to increase it for giant planets.. the effects of the primary ( co - orbitals ) co - rotation resonances are more pronounced for larger planets than for smaller planets, with the latter being more likely to be due to the presence of a gap - clearing planet.
the two - dimensional ( 2d ) weyl superconductor is a member of the new family of materials characterized by the presence of weyl fermions in the band structure @xcite.   however, the 2d weylsuperconductor has received very little attention because of the difficulty in realizing such a phase. in this work  , we propose a new heterostructure consisting of a half - metal ( hm ) with rashba spin - orbital coupling ( rsoc ) and a spin - singlet supercond conductor that can be used to realize a type - i and type - ii weyl node in a supercondonducting phase. for the first time, we show that the existence of a single nondegenerate fermi surface and the possible existence of nodes in the order parameter of the spin - triplet pairing by the rsoc make the hm layer of the proposed heterostructures a unique platform to realize the 2 d weyl Superconductor.
we present results from the first @xmath910deg@xmath10 of a newton telescope wide angle survey ( was ) of quasars at high redshift.   the survey consists of single 600secs exposures in 5 wavebands over an area @x Math9100deg@ xm10 to a nominal 5@x maths15 limiting magnitude(vega ) of 23, 25, 24, 23 and 22 respectively. for the current work we have only used data with seeing of @x math11.67 arcsec ( fwhm of 5 pixels ) and stellar ellipticity ( due to trailing ) of better than @xMath10.2 since this defines a practical upper limit for reliable image morphological classification. using these data we show that the majority of the ionizing flux is due to starlight - driven star formation at z=3.5 which is consistent with the inferred star formation rate at z = 5.5 or higher. however, we also find that the proportion of the universe that is ionized by starlight is lower than expected based on the observed value of the gunn - peterson trough in the spectra of many high redshifted objects. here   we
nonspherical nuclei in neutron star matter ( nsm ) are expected to affect the neutrino transport and hydrodynamics in supernova cores.   we have investigated the effects of these phenomena on the bcc lattice of spherical nuclei by calculating the associated static structure factor for the region of nsm where the nuclear density is about to change from a crystalline solid to a liquid phase. using the thomas - fermi model, we show that the spatial structure of the nuclear matter region changes with increasing density and that the existence of " pasta " phases with slablike and rodlike nuclei results in a significant decrease of the maximum elastic energy that can be stored in the inner crust. as for pulsar glitches and cooling of neutron stars, it is interesting to note that the presence of such phases would also accelerate the cooling of the corresponding region of neutron Stars by opening semileptonic weak processes which are unlikely to occur for sphericaluclei.
bilayer manganites such as the @xmath1 member of the ruddelsden - popper series @xcite are very rich in their charge, magnetic and orbital structures.   it is now generally believed that the various magnetic structures owe their origin to a large degree to the underlying orbital order@xcite. here   we investigate the question of charge order and possible phase separation in the overdoped bilayer systems using a model that incorporates the orbitals of the mno@xmath12 octahedra and the c - type ferromagnetic chains coupled antiferromagnetically. at low temperatures,   the a- and c - phases are orbitally ordered and there is a connection between the preferred orbital order and the observed magnetic order. however, the presence of charge Order and its relation to the corresponding magnetic phases have not been investigated in any of the previous theoretical studies in the bilayer system so far. by combining the experimental evidence of both charge and orbital order in at @x Math0 and the theoretical evidence of a coexistence of charge ordered and layered a - type spin ordered states, we show that the latter can be used to explain the enhanced af super - exchange in the
the initial stellar mass function ( imf ) of the large Magellanic Cloud ( lmc ) is a power law function that has been observed directly in dozens of clusters in our galaxy and in the large magellanic clouds, and inferred indirectly from metallicities, supernova rates, ionization levels, luminosities, dynamical masses, colors, and other tracers.   it is generally accepted that the power law part of the function is invariant at intermediate and high mass, with a slope between @xmath1 and @x math2 on a histogram, and a flattening below this down to @x Math4 m@xmath0 or lower. however, scalo ( 1998 ) recently emphasized the variations in the derived power law slopes from region to region, which amount to about @x maths6.    we show that these variations are due to physical effects, including the formation of new stars in the cluster density, galactocentric radius, metallicity, and metallicities of the star - forming regions, and also to the chemical evolution of the cluster itself. for each of these factors,   the power Law slope is fairly constant, around the salp
relativistic calculations of three - nucleon ( 3n ) scattering are compared to nonrelativistic predictions of the same data using a poincar invariant model.   the two - body interactions for each pair of atoms in the nuclear hamiltonian @xcite are added to the center of mass kinetic energy operator to obtain a scattering matrix that clusters into a product of the identity and the input 2-body @xmath0-matrix, which is related by a non - linear dependence of the three - body invariant mass operator on the second - body s - matrix. at the same time the internal and single particle variables are related by galilean or lorentz boosts in both cases. in the relativist case   these boosts are more pronounced than in the nonrelatsivistic case where the galileans are boosted by lorentzi boosts. while the relativalism of the scattering matrix cluster properties is not affected by the effects of the galilesan boosts, it is influenced by the Lorentz boosting of the centers of mass operators.
we investigate the influence of intermolecular interactions on the magnetization of quantum heisenberg antiferromagnets in one, two and three dimensions by means of quantum monte carlo@xcite ( qmc ).   we show that the interaction ratios of the inter- and intramolecular coupling must be smaller than about 10  % to mask the fingerprint of the underlying molecular subunits in order to modify dc magnetic observables so drastically that the fingerprints of the individual molecules are masked. for systems embedded in a space dimension of 1.0, 2.0 or 3.0    0.5  cm2   the results are compared with the scenario of j - strain, that sometimes is also taken into consideration for the interpretation of experimental data.
the calice collaboration is developing a granular sampling electromagnetic calorimeter ( ecal ) using scintillator strips read out with pixelated photon detectors ( ppds ) as the sensitive layers interleaved with tungsten plates as the absorber layers. in this paper   the technical prototype developed such thinner and dense readout board is introduced in the successive section. to extract the fine segmentation performance with scecal, a special event - reconstruction method is required and it has been developed.   such reconstruction method, called the strip splitting algorithm ( ssa ), is shown and discussed, including the way where we use tile layers between strip layers. finally we summize the optimization of scescal in section .
we investigate the dipole - dipole interaction - induced shifts in the clock transition frequency recovered by ramsey spectroscopy in three - dimensional optical lattices of alkaline earth atoms.   we show that by varying the lattice geometry we can quantitatively control the clock frequency shift and even reduce the shift to zero. for atoms in the lamb - dicke regime, this is achieved by changing the relative orientations of the trapping beams, whose degrees of freedom can be characterized by a set of variables @xmath8. when the trapping lasers are constrained to operate at the  magic " wavelength, the magnitude of the line shift scales approximately like@xmath10.    in particular, we give an analytical equation that can be solved giving configurations where constructive interference causes the lineshift to be very large. in these  bad " lattice configurations,   the shift is cancelled by tuning the parameter space to lie in between two of the bad configurations, and the mechanism of cancellation is associated with the destructive interference of contributions to the shift from different atoms in each lattice.
the quantum chromodynamics of the quark gluon plasma ( qgp ) is a well - studied problem in the heavy ion program at the accelerators rhic ( brookhaven ) and lhc ( cern ).   the qgp phase is separated from the hot gas of hadrons by a cross - over  @xcite at high enough collision energies to leave an imprint in the abundance of various particle species that are created at the break - up of the plasma, and the transition temperature can be modelled as a function of the collision energy or baryo - chemical potential. here   we study the order of the transition between qgp and the confined phase, the polyakov loop and the chiral condensate, for several sets of quark masses, complemented by a measure of the confinement of strange quarks, the strange quark number susceptibility. with increasing quark mass   it is shown that the transition is dominated by the restoration of chiral symmetry, signalled by the vanishing of the chirality condensates. for intermediate masses   there is no real transition and both the monotonically decreasing polyakov loops and the remnant order parameters are approximate,
a general method for the determination of the oscillation periods of the interlayer coupling between metallic magnetic layers across a non - magnetic spacer is presented.   the relation between the periods and the spacer fermi surface ( fs ) is clarified and in addition to the usual periods, the general conditions for occurrence of non - rkkyo behaviour are also established. similarly to previous theoretical approaches@xcite, an expression for the coupling in the asymptotic limit of large spacer thickness is derived. here  , the occurrence of multi - periodicity for a single value of @xmath1 becomes evident at the same time that the relationship between the oscillations and the fs is clarified.the results show that the existence of non-rkky behaviour is proved to be possible in the case of a fcc lattice along the direction @xcite with a thick spacer. moreover, it is shown that the origin of the observed multi - periodic oscillations is not related to the ruderman - kittel - kasuya - yosida ( rkki ) theory but to the quantum well theory.
the rotating brane - black hole system is a generalization of the problem of topology changing and merger transitions between higher dimensional black solutions, which has been recently introduced by frolov @xcite.   we present and analyze the general solution of this problem, first analytically in far distances, and later numerically in the near horizon region. as a result  , we obtain that due to the coordinate parametrization of the myers - perry metric, this rotating problem is not compatible with the spherical results of@xcite, in the sense that the latter ones are not recovered in the non - rotating limit. furthermore, we also find that stationary equatorial solutions do not generally exist for arbitrary brane dimensions, except again for the case of a 3-dimensional brane.
eaims ( emergency analysis identification and management system ) is a new crisis tracking and analysis toolkit, which aims to provide automatic identification, tracking, summarization and exploration tools over social content generated during emergency events.   eaims differs from most existing crisis analysis toolkits, in that it provides a richer suite of automatic tracking and analyses tools, namely : automatic event detection, timeline construction, targeted sentiment analysis, user - community identification and information credibility estimation, as well as information access support tools in the form of social media search and discussion threads ranking and visualization.    eaimss is social media platform - independent, making it applicable to deployment in regions that use alternative platforms.. the eaimrs toolkit is available at http://www.ebis.org.cn/emergency-analysis-identification-and-management-toolkit.html.
we develop theoretical tools and experimentally demonstrate the simulation of arbitrary free - space channels with intensity fluctuations.   we use measurements at different fixed attenuation levels and subsequently weight and merge the obtained data to analyze the sought - after atmospheric model. in particular, we focus on the fluctuating intensity losses and demonstrate how they can be simulated in a controlled manner. as our source of nonclassical light  , we utilize an on - chip - integrated down - conversion source @xcite, which is advantageous for satellite based quantum communication due to its small size and low weight. using the measured click - statistics, we infer the reference model for the atmospheric transmittance of quantum light propagating through the link and then combine the results with the experimental data to obtain a more accurate model. by combining the two data sets, we find optimal quantum states, evaluate detection methods, identify limitations in the performance, estimate the achievable quantum bit rate, and others.
recognition of line objects is a complex problem that can be solved in many ways.   it consists of more phases depending on approach. each phase affects next so it is important to obtain good results after the first ones.. pre - processing is the first step in all methods.    it modifies input raster to enhanced important information and wipe out those that can cause future problems ( like noise ). in the next step we usually use some type of thinning to create skeleton.,1 so the image become reducing all lines to single pixel thickness. ,2 this paper focuses on the morphological operations using hypergraph and thinning process can be applied, which is essential for many image processing tasks including line objects recognition.
we investigate the magnetism of cscl - type fese by using density - functional theory ( dft ) calculations.   we find that cscl-type fese demonstrates both ferromagnetism and antiferromagneism over a wide range of lattice constants in terms of density -functional theory, including the total - energy all - electron full - potential linearized augmented plane - wave ( flapw ) calculations implemented in the qmd - flapw software package  @xcite. for the ferromagnetic phase,   the flapw calculations show that the exchange - correlation potentials are strongly correlated with the spin - density wave ( sdw ) and the charge density, which can be attributed to the presence of fe clusters or fe clusters in the fese thin films. for superconductive@xmath7-fese, where the sdw is strong, the results indicate that the xo scheme is employed to ensure the orthogonality between the core and valence states.
dilute magnetic semiconductors ( dmss ) are a new class of materials in which transition metal dopants ( usually co, fe or mn ) replace native cations in ordinary semiconductor.   the most commonly used dopant in this case is co and at present the claims for room temperature ferromagnetism in zno : co, following the first exciting report from ueda et al.  are numerous.    the experimental literature however is populated with controversial results and almost all possible magnetic phases have been found in samples with the same nominal co concentration and grown under apparently similar conditions. erythroid - like defects on the surface of secondary coo phases have also been proposed as the origin of magnetism. here
the fruit fly is considered to be one of the smallest flying insects with a wingspan of about 6 mm.   it flies at about 200 wingbeats per second, which yields a reynolds number of about 120. in typical insect flight, lift is produced when a leading edge vortex remains attached to the wing, and a trailing edge vortex is formed and separates from the wing during each stroke. as the reyn olds number is lowered from 100 to 1, the relative lift forces produced during flapping flight decrease while drag forces increase significantly. here   we show that these transitions are associated with a change in the behavior of the vortex wakes behind the flapping wings.
we study the adsorbate - induced faceting of a curved bcc(111 ) crystal surface by using a solid - on - solid ( sos ) model.   we focus on changes in surface morphology in the vicinity of the @xmath0 $ ] pole, where step - like \{211 } facets were observed in fim ( field ion microscopy ) @xcite and fem ( field emission microscopy)@xcite experiments. for this purpose,   monte carlo simulations are used to study the effect of annealing at elevated temperatures on the formation of pyramidal facets in accordance with experimental observations. after depositing a metal film ( e.g. pd, rh, ir, pt, au ) or oxygen layer and annealed at elevated temperature, an increase of the macroscopic \{110 } and \{21 } crystal facets is observed near the @Xmath4 poles, where steps - like microfacets are formed. moreover, the model describes a reversible phase transition from a faceted surface to a disordered ( 111 ) surface.
the tissot ( 1881 ) indicatrices have been very useful for providing a visual presentation of local distortions in map projections in a simple and compelling fashion.   the tissot ellipse essentially carries the information on the metric tensor for the map, but it does not tell us how local infinitesimal distances on the map correlate with local infInitesimal distance on the globe. in this paper   we show a simple way to visualize these distortions in sec. , in which we introduce the " goldberg - gott indicatrix"s. by showing a face on a globe with a triangular nose, a straight ( geodesic ) mouth, and eyes that were pairs of concentric circles on the globes, we show that the mouth is straight, but the eye circles are not circular ( what we would call flexion ). in sec.  we show another distortion : skewness, which represents lopsidedness and an asymmetric stretching of large structures. insec.  we derive a differential geometry approach to measuring flexion and skewnesses.
the belousov - zhabotinsky ( bz ) reaction is often used as an experimental model of the reaction - diffusion systems @xcite. in this system,   chemical waves propagate at a constant velocity and amplitude and, thus, exhibit the characteristics similar to those of pulses in nerve cells. in the present study, we show that a chemical wave slows, stops, and then disappears in a narrowing glass capillary.   we discuss this phenomenon in term of the surface volume ratio for the reaction field, i.e., the surface can seriously affect propagation of the chemical wave.
the local density approximation ( lda ) is a commonly used to study the nature of phase transitions in spatially inhomogeneous systems.   the lda assumes that the properties of the confined system at a particular spatial location are identical to those of the unconfined system with a uniform potential taking the same value as the local potential at that location. here  , we examine the validity of this approximation within a more simple classical context, and show that it yields very good results in a number of contexts, especially when the electron - electron interactions are of weak to intermediate strength. on the other hand, when the coupling is stronger, and phenomena like magnetism and mott transitions occur, the l da is less accurate.
single particle tracking microscopy provides the position time series of individual particle trajectories in a medium @xcite.   the information garnered by single particle tracking yields insights into the mechanisms and forces, that drive or constrain the motion of the particle. particularly in biological cells and complex fluids  , single particle trajectory methods have become instrumental in uncovering deviations from normal brownian motion of passively moving particles. here   we discuss in detail the behaviour of passive subdiffusive motion in terms of time and ensemble averages and address the peculiarities, that may arise for non - ergodic systems.
in previous papers, we proposed a resonant excitation mechanism of disk oscillations in deformed disks. in this paper, we modify the analyses in our previous papers so that the above - mentioned inadequate treatment is corrected.   we find that the resonant point is not the place where a local dispersion relation of the intermediate oscillations is satisfied with a constant @xmath2, but the radii of lindblad resonance for intermediate oscillation ( when resonance occurs by horizontal motions ) or the radies where the intermediate harmonic oscillations are trapped in the vertical direction.
the network - layer performance analysis seeks to provide estimates on the delays experienced by traffic traversing the elements of a network, as well as the corresponding buffer requirements. for wireless networks,   a question of interest is how the stochastic properties of wireless channels impact delay and backlog performance. in this paper   we explore the network - layers performance of a multi - hop wireless network where each link is represented by a fading channel.   our analysis takes a system - theoretic sto chastic network calculus approach, which describes the network properties using a @xmath7 dioid algebra. from these characterizations  , we derive a method to compute bounds on the end - to - end delay and on buffer requirements for a cascade of fading channels, with store - and - forward processing at each channel.
the electroweak phase transition ( ewpt ) is a process in which the electroweak gauge symmetry is reduced from @xmath1 to@xmath2.   the nature of this transition is a subject of considerable interest, as it would have far - ranging implications : for example, electroweak baryogenesis, which theoretically is arguably the most attractive mechanism proposed to explain the observed matter - antimatter asymmetry, can only occur if the e wpt is strongly first - order.. we show that the value of the higgs boson cubic self - coupling is one of the simplest observables that can be correlated with the order of the phase transition. using three toy models, we argue that these models predict a large deviation of the cosmically relevant higgs cubic coupling from the standard model ( sm ) value.    we find that this is the case in all three models, and that the deviations are due to accidental cancellations between large corrections to the lifetimes of the potentials of the weak - doublet higgs and singlet scalars at the weak scale. by contrast, the effects of the nonrenormalizable operators in the potential and the mixing between the weak- and strong
the @xmath0-nucleus quasi - bound states of eta meson are studied using the heavy - baryon chiral perturbation theory up to the next - to - leading - order terms. combining the relativistic mean - field theory for nuclear matter with the chiral and effective chiral lagrangian in heavy - fermion formalism   @xcite, we obtain the in - medium properties of @x Math0-meson in uniform nuclear matter.   the @x math0-neu optical potential is found to be 280@xmath2130 mev at the normal nuclear density, while the depth of the optical potential has been calculated to be @x maths10 mev.
synchronization of chaotic systems is a very interesting phenomenon that has been extensively studied and which, in addition to its role in modeling natural systems, may have technological applications, for example in the field of secure communications.   however it has been noticed by several authors that there are situations where one obtains synchronization even with positive conditional exponents and clustering or strong correlations of the subsystems even when they are desynchronized.the method to be used in this paper is also to study a concrete example but one that is sufficiently simple for almost everything to be exactly computed and from which essential features may be isolated from model details. in particular, by using piecewise linear maps one gets rid of second order effects and non - uniform hyperbolicity.    also the fluctuations in the mean field, seen by each element of the coupled system, seem to be rather tame and the origin of the correlations and structures may be correctly identified. once the behavior of these phenomena is clearly understood in this model we will then attempt to separate what seems to be universal features and what are particular features of the model.
living systems as far - from - equilibrium open systems, are essentially cognitive, and conversely, in order to grasp the essence of cognition, one may attempt to understand the ontology of the former processes. here   we take a further step forward that incorporates a number of related factors mainly following the ( generalized ) onsager relations of non - equilibrium thermodynamics combined with the principles of _ rate distortion _ theory which is one of the mainstays of shannon s pioneering work.   one particular observation is that distortion in communication between interacting cognitive modules, is patently stochastic, in particular, it is manifestly a process of brownian motion. by considering critical solutions for the distortion, we argue on a case - by - case basis that the ensuing Brownian motion ( viz weiner process ) can be locally one of bounded variation. accordingly, we are motivated to introduce the necessary conditions that permit integration of these equations into a kind of master equation that allows us to obtain _ a new model of cognition. this model is based on the notion that the interaction between cognitive modules is governed by a set of differential equations that are localised to the individual cognitive modules and their interactions with each other, and that they are
we show that the properties of a particular class of periodic isostatic lattices derived from the two - dimensional kagome lattice by rigidly rotating triangles through an angle without changing bond lengths are highly sensitive to changes from free boundary conditions to periodic boundary conditions.   the elasticity and mode structure of these lattices are strongly influenced by the type of lattice architecture, which determines the degree of sensitivity of the deformation modes to change from free to periodic boundaries.
the spin - resolved orbital magnetization of a two - dimensional electron gas with rashba spin - orbit interaction is calculated in the framework of green function formalism and kubo formula.   the model is introduced and the spin vector potential is introduced to calculate the relevant green function, which is used in sec.1 to describe the spin current in thermal nonequilibrium. for the system with time - reversal symmetry,   it is shown that the spin - dependent orbital magnetizations are suppressed due to the time - reverse symmetry.    the spin currents generated by the electric current due to a nonzero orbital magnetic field can be used to control the spin nernst conductivity of the system.
the cool algols are a new class of interacting binaries that contain a late - type giant or subgiant that is transferring mass onto a much more luminous and more massive b  a main sequence star.   only about a dozen of these systems are known, and many of them were mistakenly assigned to the larger group of rs  cvn binaries which contain a luminous k - type primary with a fainter f  g type companion. here   we present a re - analysis of the spectroscopic orbit of bd@xmath1706 ( rxj0441.9@x Math100537, ppm  147827, @xmath12, @Xmath13, j2000, & v756  sco ; paper  i ), which was discovered in the course of follow - up observations of a sample of x - ray sources selected from the rosat all - sky survey south of the taurus - auriga star - forming region @xcite. using improved techniques and the benefit of the additional information provided by the light - curves, we have determined the absolute masses and radii of the two components of the system. for the first time, we
abstractan orbitope is the convex hull of an orbit of a compact algebraic group acting linearly on a real vector space.   the orbit has the structure of a real algebraic variety and is a convex, semi - algebraic set. in this paper   we review the study of orbitopes as geometric objects in their own right from three different perspectives : convexity, algebraic geometry, and optimization. to begin with  , we will discuss the concept of orbitalopes as semidefinite polytopes which are also known as spectrahedra or projection matrices. by taking the action of the group @xmath7 on the space of binary quartics, we show that the orbitope (  ) is a _ carathodory orbitope_. we will also show that if an orbitope admits a representation (  ) then it is easy to maximize or minimize a linear function over that orbitope.
we find a simple class of flow solutions from ads@xmath0 to sch@x math11 after deforming a class of relativistic quantum field theories ( cfts ) with a mass operator.   the solution is based on the uv cft dual of the so - called skew - whiffed @xmath22, where @x Math23 denotes 7 dimensional sasaki wavelet in m - theory, and we study the physics of the spacetime of the same dimension as that of the shapiro - schrdinger geometry @xcite. by combining an internal direction with four directions, performing the coordinate transformation (  ) to have a time conjugate to the non - relativists energy, and finally taking the scaling limit (  ), we show that the gravity dual of this theory can be obtained by deforming the 3 dimensional relativismic cft@x maths21 by a mass term preserving all poincare supersymmetries, considering a particular vacuum in which all scalar expectation values are zero.
the casimir interaction energy between two eccentric cylindrical shells has been computed in @xcite.   the aim of this paper is to provide a precise numerical evaluation of the analytical results obtained in@xcite, and to test different approximations, as the proximity force approximation ( pfa ) for close surfaces, and the " around the diagonal " approximation for quasi - concentric cylinders. by using the mode summation technique combined with the argument theorem  , we show that the interaction energy for the cylinder - plane configuration can be derived in the appropriate limit from the eccentric cylinders configuration, which was anticipated analytically for the matrix elements in the general formula. also, we present a new analytic result in the small distance limit, that includes the corrections to pfa up to the second order. finally, an improved numerical method to evaluate the interaction energies at small distances is presented.
one of the key properties of living systems is their sensitivity to external stimuli, which allows them to adapt and cope with the challenges of their complex environments.   engineered systems can be thought of as roughly emulating these properties by building programs and machines that react to external inputs, which are converted into useful calculations or operations  abstract or physical  in a comparable fashion. one important question we face is how we are to evaluate artificial systems in a fashion comparable to natural systems, when it is so difficult to determine measures of performance for natural systems in the first place. for intelligence, for instance, critics assert that it only measures how good a person is at taking an objective test of intelligence, i.e. the intellectual quotient ( iq ) test. however, this is not the case, as a general computer program to answer arbitrary questions on an iq test is relatively easy once these questions are classified under the headings of arithmetic, word relationships and shapes, for example. since intelligence is an observer - dependent property, it is necessary to accept that the question of what constitutes intelligence, not only in humans but in machines, is difficult, if not impossible, to answer in a definitive way, and become reconciled to
we investigate the number of cyclically symmetric tilings of a generalized douglas region and a hybrid between the aztec diamond and a hexagon on the square lattice with every third diagonal drawn in, called _ quasi - hexagons.   we use the subgraph replacement method to show that the number is the same as that of the symmetric tiling of a hexagonal on the triangular lattice, up to a multiplicative factor. by using the sub graph replacement method, we also enumerate the perfect matchings of an aztec rectangle graph with holes, that itself can be considered as a generalization of the related work of b.y. yang@xcite and m. ciucu @xcite in the case of aztec diamonds.
we report the first galaxy count at a wavelength of 450@xmath0 m from the scuba lens survey data.   we use the detections of four high - redshift dusty galaxies in the 450-@x math0 m scuba to yield counts of galaxies detected at a depth of 0.5mjy through the cores of seven massive cluster lenses. using our monte - carlo method, we find that the mean number of galaxies per cluster at this wavelength is about 10 times higher than the 850/450-@X maths0 m surface density at 3mj y.
we present a new method for the calculation of the parton distribution functions ( pdfs ) for virtual photons in leading order ( lo ) and nlo using perturbative qcd ( qcd ) at hera.   the method is based on parametrizing the @xmath11-evolution equations of theparton distributions and the input distributions at @x Math12 with changing @x math2.    the results are compared with experimental data from the zeus and h1 collaborations at heRA, which show that the cross section for the production of two or more high-@xmath3 jets at leading order can be predicted as a function of the number of interactions between the photon and the protons in the range of @x maths2 to @xMath2.5 in the absence of the direct photon process. also the cross sections for the single inclusive and dijet inclusive one - jet cross sections in lo have been calculated for the proton - proton quenching process for the case of quasi - real photons, i.e. photons of extremely small virtuality ( < 0.01 gev ).
the history of heavy element generation via the nucleosynthesis in stars and succeeding pollution of the interstellar medium ( ism ) is expressed as " chemical evolution ".   the - relations are used as the chronometer for the formation history of the galactic stellar system. during stellar evolution,   heavy elements are synthesized from hydrogen ( h ), helium ( he ) and a small amount of lithium ( li ) by the reaction of the proton with oxygen ( o ) or magnesium ( mg ) in the star and then released to the ism through the pollution by type ii supernovae ( sne ii ). on the other hand, in the intermediate mass star binary systems ( sne ia ), heavier elements such as iron ( fe ) and nickel ( ni ) are also synthesized efficiently. here  , we discuss the observed features of the @xcite relations in the early phase of the chemical evolution, which are explained by the interaction of these two processes.
monte carlo event generators for hadron colliders like the tevatron and lhc are powerful tools for experimental high - energy physics.   they provide a detailed description of the final state so that, ideally, any experimental observable or combination of observables can be predicted and compared with data. in this article  , we describe the physics picture and the generator landscape, including the usage of matrix elements, the important topics of initial- and final - state showers, and how showers can be matched to different hard processes.the article concludes with an outlook on the ongoing generator - development work.
in heterogeneous many - particle systems, where typically different energy scales, associated with the inter - particle interactions, compete with each other, the formation of stable composites is a complex process.   this is even more relevant if the many - particles exhibit constraints such as covalent chemical bonds restricting the mobility of atomistic or monomeric subunits and the flexibility of the molecular system to adapt to environmental conditions ( solvent, temperature, pressure, etc. ). in this review,   we focus on the thermodynamic phase behavior of homopolymers, i.e., linear, linelike molecules in solvent, which can be classified into groups of flexible, semiflexible, and stiff polymers based on the fundamental length and energy scales associated with covalently and non - covaluously bonded backbone geometries. for very long chains of monomers, the general structural behavior of polymers is typically described by geometric quantities such as the end - to - end distance @xmath3 and the radius of gyration@xmath4, the latter being a measure for the compactness of the polymers. however, only a few system parameters, e.g., the polymer chain length
we study the vortex polarity switching behavior of a magnetic vortex under the action of a perpendicular ac magnetic field in the 10 ghz range.   we use the discrete discrete reduced core model, which allows us to describe different regimes of vortex polarization dynamics, including the resonant behavior, the weakly nonlinear regimes, the reversal dynamics, and the chaotic regime. using the collective coordinate model we propose a way of a unidirectional switching controlled switching process.
lmc x-1 was one of the first x - ray binaries discovered, and the first one found in magellanic clouds.   the optical counterpart of this star has been identified as star 32, which is a fainter ( @xmath4 = 12.0 ) b5 supergiant with an orbital period of approximately 4 days. here   i show that the orbital period for star 32 is about 4 days, and that the mass ratio of the optical component to the compact component should be about 2. from the radial velocity measurements of emission lines, discovered by pakull ( 1980 ),   these lines probably originated near the secondary ( compact ) component, and, from the relative amplitudes, the authors deduced that the masses of the two components should exceed 2. the results are consistent with the observations, and support the existence of a compact component.
radio jets are known to trigger star formation in galaxies, but they have not been considered as a major actor in the process of galaxy formation until now.   recent evidence for jet - induced star formation has been found in various objects and environments, either far away from the host galaxy, such as in the lobe of radio jets or inside the host Galaxy, resulting in the so - called radio - optical alignment. since the masses of supermassive black holes ( smbh ) and of stars in galaxies are correlated, it is natural to consider the alternative possibility that both processes are related, with one possibly affecting the other. here   we review the current knowledge on the role of radio Jets in galaxy formation and discuss their potential as a driver of star formation and maybe even galaxy formation.
we propose a so - called " debugging " method to deal with quantum computing errors that are not caused by environment noises but by " bugs ", which mean unknown defects in the physical system itself.   quantum measurements are used in this way : they are constantly taken to monitor a quantum process but without disturbances on the system state, until an error is detected. for example, if a bug of the system will be involved in the process at time @xmath3, then the system hamiltonian will not truly be @x Math1 for @x math4 in the practical execution. as a result,   the system can be successfully implemented with high probability if each component of the systems only fails with probability less than a threshold.. the debugging method proposed in this paper is based on the concept of zeno effect, in which the system states of the quantum process are monitored continuously by measurements, but without disturbance, until the error is found and repaired.
parity violating electron - nucleus scattering is important for several reasons.   first, it provides a test of the standard model at low energies and is sensitive to strange quarks in the nucleon or nucleus. here   we show that elastic parity violating asymmetries from several nuclei are modified by coulomb distortions. these effects are of order @xmath7 ( where @x Math8 is the nuclear charge ) and modify the asymmetry. using a relativistic optical model, we calculate the effects of these distortions with accuracy to about 1.5 percent. even with distortions,   this asymmetry is very sensitive to neutron densities and an experiment to measure the neutron radius in a heavy nucleus is feasible.    we also conclude that cou lomb distortions are important for a one percent standard model test in@xmath9 or @x math10 and that such a test may be sensitive to very small differences in proton and neutron radii.
we investigate the properties of a new heavy neutral particle which could be discovered in high energy @xmath6 collisions.   we concentrate on the class of models where the di - photon decays of such a particle will be the first decay mode to be observed experimentally. based on this model  , we propose that the new particle may have cp - even, cp - odd or cp - mixed parity. by studying the jet distributions from the production vertex of the spin-0 scenario, we investigate the effects of these three assumptions of parity on the production mechanism of the proposed particle.. the results show that the production cross section of the hypothetical particle would lie in the broad range of @x Math12 fb, depending on the model and the resonance mass @xcite. using this model, we outline the experimental observables to be investigated to understand its exact nature.
the kinetic roughening of surfaces has become a field of increasing interest.   many papers have appeared concerned with computer simulations of surface growth. in the present paper   we wish to examine the implications of some of the standard assumptions in the theory, and in particular to provide a mapping of prescribed rules of growth to the corresponding differential operators appearing in the associated stochastic growth equations.
the ziman variational approach to the thermal conductivity and the electrical resistivity in metals is presented.   the model of the charge carriers by _ phonons _ is considered within the boltzmann equation formalism, an approach in which the notion of " relaxation time " is not used. for the transport coefficients the wiedemann   franz law is applied, but the validity of this law is restricted to elastic collisions.    the results are compared with the results of the mott formula @xcite, which is usually used to treat the thermoelectric power under the assumption of the matthiessen rule.
the color superconductor ( csc ) phase of the quark matter is considered to be a condensed state of quark pairs called the diquark condensate, where the color @xmath4 symmetry is spontaneously broken.   the csc phase is described by the bosonic degrees of freedom of the isolated quarks in equilibrium with the in - medium resonant / bound states of two fermions, which are identified as the bec-@xmath14 of difermions under the quasi - chemical equilibrium theory. for the strong - coupling region of the Quark matter, the coherence length and the strength of the two - fermion correlation   are shown to be very small, even around the moderate - density region, which implies that the strong quark - pair correlations are described by bosonic degree of freedom, which we call "diquark " in this paper. here  , we present a new method for the calculation of the transition temperature of the baryon - number density in the weak - coupling limit of the qcd   @xcite model of the hadronic matter at sufficiently high temperature and/or large baryons - number densities.
fully convective stars are considered the simplest stars to describe from a theoretical perspective.   they are largely characterized by near - adiabatic convection and are generally assumed to be fully convective by stellar structure models. however, discrepancies between observations and model predictions of full - convective star radii have been observed in detached eclipsing binaries ( debs ) with mass and radius measurements with precision below 3%. while strong magnetic fields maintained by tidal synchronization are currently considered the leading culprit producing the observed radius discrepancies, several clues suggest otherwise. here   we review the evidence mounting against the magnetic hypothesis, including the presence of inflated low - mass stars in long period debs and the discovery of koi-126, a pair of fully conveful stars in which orbital and stellar properties can be accurately characterized by stellar evolution models.
spinor field has been considered as an alternative source of bianchi type - i cosmological model for dark energy in recent years.   this is because of the fact that spinor field is related to almost all stable elementary particles such as proton, electron and neutrino. however, in cosmology, the role of spinor fields was generally considered to be restricted. only recently, after some remarkable works by different authors @xcite, showing the important role that Spinor fields play on the evolution of the universe, the situation began to change. here   we review the current state of knowledge about the contribution of spinors to the history of cosmic evolution.
we show that the twosheeted structure of the kerr - schild geometry is in perfect agreement with the required holographic structure of quantum black hole spacetimes described by stephens, t hooft and whiting in @xcite.   we obtain exact solutions of debney - kerr-schild equations for electromagnetic excitations of the bh and the horizon and their back reaction to metric and horizon using a semiclassical fluctuating kerr ( robinson and carter ) geometry which takes an intermediate position between the classical and quantum gravity. this geometry has a classical fluctuating fine - grained structure which shows that the usual representations on the structure of bh as well as the horizon may be naive and very far from reality.
we develop a general approach for the analysis of wave scattering in quasi - one dimensional waveguides with two corrugated surfaces that are either statistically uncorrelated or correlated.   our main interest is in the expression for the _ attenuation length _ @xmath0 ( also known as the scattering length, or the total mean free path ), corresponding to specific@xmath1-th propagating modes.    we assume that due to the multiple scattering of a travelling wave from the rough boundaries, the longitudinal wave number of an @x Math1-h propagating mode can be written as @x math8, where @x maths9 is its unperturbed value, and the real part @xMath11 is responsible for a roughness - induced correction to the phase velocity of a given mode.. the so - called " repulsion " phenomenon discovered in ref.  is also discussed.
the hippocampus is one of the oldest parts of the mammalian brain in evolutionary terms.   it is believed that mammalian ability to navigate, to escape from predators, to find its nest, to plan hunting strategies and so forth, is based on an internalized neuronal representation of space  a cognitive map of the environment, which is encoded via timed sequences of quick electrical discharges of the neurons   neuronal spikes  in various parts of this brain.    experimental evidence points out that groups of coactive place cells form functionally interconnected " assemblies" that together drive their respective " read - classifier " or " readout " neurons in the downstream networks.. since coactivity of the place cells marks the overlap of their respective place fields, the activity of a readout neuron actualizes a connectivity relationship between the regions encoded by the individual place cells., this suggests that the hippocampus provides a qualitative representation ofspace, based on connectivity, adjacency and containment relationships, i.e., that the hippocampal cognitive map is topological in nature. 	 however, the approach of @xcite was based on analyses of the ever - growing pool of spike trains, namely, it ignored that, in physiological networks, the
we propose a method to find ultra - high energy ( uhe ) proton or light nuclei sources on top of background and reconstruct their positions.   we show that one has to start from at least two events with energies above @xmath3ev@xmath4ev before looking at lower energy tails, in order to avoid confusion by the background. for source events, we assume power law acceleration spectra, with a power law index equal to 2.2 and a maximum energy set to 10@x Math13mpc. in most cases, we take a proton source and set its distance to the earth to @x math14mpc ; protons are propagated to the observer by using the results of the hires experiment for energy losses, which creates a " bump " in the source spectrum.    then, the generated cosmic rays are deflected in the regular galactic magnetic field ( gmf ), and spread randomly around it in a sector - shaped region. when there are many events with the same energies, they are not spread uniformly, as discussed in references  . results depend on many parameters of the model and on the considered location on the sky. however, in practice, there are
we propose a new class of models which generate three - dimensional random volumes, by regarding each random diagram as a collection of triangles glued together along multiple hinges as in @xcite.   our models have real symmetric matrices as the dynamical variables and are characterized by semisimple associative algebras @xmath0. although most of the diagrams represent configurations which are not manifolds, we show that the set of possible diagrams can be drastically reduced such that only ( and all of the ) three -dimensional manifolds with tetrahedral decompositions appear, by introducing a color structure and taking an appropriate limit of parameters existing in the models. since our models are written with matrices, there should be a chance that various techniques in matrix models can be applied and the dynamics of random volumes can be understood more analytically. here  , we discuss the analytic solvability of our models.
we prove that the regular gaussian distributions that factorize with respect to a chain graph @xmath0 with@xmath1 parameters have positive lebesgue measure with respect.   this means that, in the measure - theoretic sense described, almost all theregular gaussian distribution that factorizes with Respect to @x Math0 is faithful to it.    we also show that for any undirected graph and for any acyclic directed graph, there exists a regular gaussian distribution that is faithful on the sole basis of @x math0. under the alternative andersson - madigan - perlman interpretation of chain graphs,   the results are similar to those previously proved for strictly positive discrete probability distributions with arbitrary prescribed sample space.
cold dark matter ( cdm ) is now widely believed to make up the bulk mass of the universe.   it is thus conceivable that the cdm particle can be nestled far below the weak scale provided that its couplings to the standard model ( sm ) spectrum are sufficiently suppressed. in the present work  , we build a conservative cdm model by modifying the sm in a minimal way, and observing that :   a lightweight cdm sector naturally arises if it derives from a conformal - invariant dark sector that couples conformally to the sm particles.the reason is that all the scales in the dark sector, thecdm mass in particular, are directly generated by electroweak breaking, and, in general, the smaller its coupling to the higgs field, the lighter the cd mb particle. also, conformal symmetry naturally accommodates the @xmath0 symmetry required for longevity of the cdM particle.in what follows, we shall construct the CDm model explicitly and analyze it against the latest results form planck and lhc.
ngc  253 is one of the nearest star - forming galaxies to ngc  253, and has been extensively studied from gamma - rays to radio wavelengths.   this paper describes the results of a series of high - resolution, wide - field radio interferometric observations of the central nuclear region of ngc 253 at 15  ghz ( 2  cm ) with the very large array ( vla ) at 3.44  @xmath6  0.13  mpc. in total, 64 compact sources were identified, including the original nine from th85, which were resolved into parsec - scale shell - like structures by combining multi - wavelength, high resolution radio observations of 46 compact sources in m82 using the vla. for each of these sources,   the spectral index measurements were obtained for the 17 brightest sources at 1.8, 5, 8.3, 15 and 23 ghz, and the distance between the source and the nearest galaxy was estimated as 3.47, 3.46, 4.07 and 3.40  kms. based on these results, we propose that the distance from the center of the supernova to the closest galaxy is ~1
the geodesic equations of motion of a singly spinning black ring in the ergosphere are solved analytically in terms of the elliptic weierstra function.   the solution is based on the jacobi inversion problem and is written in the form @xcite @xmath3.\ ]. for the rotational axis and in the equatorial plane the equations are of elliptic type, however, on the rotation axis they are of hyperelliptic type. to find the solution the equation of motion can be written in toroidal coordinates ( see  ) where@xmath4, @x Math5 and @x math6 are the toroidal coordinate systems of the ring and the metric functions are @x maths4, #5, #6, #7, #8, #9, #10, #11, #12, #13, #14, #15, #16, #18, #19, #20, #21, #22, #23, #24, #25, #26, #28, #29, #30, #31, #32, #34, #38, #39, #
quantum chromodynamics ( qcd ) is the theory describing the interactions of quarks and gluons.   it has been shown to provide excellent descriptions of a wide variety of phenomena ranging from hadron spectroscopy via lattice field theory to hard scattering phenomena via perturbation theory. in order to calculate observables measured in high energy scattering processes,   a technique is needed that allows conversion from a description in terms of hadrons to one in terms as partons. for hadrons in the initial state  , this conversion is provided by parton distribution functions ( pdfs ), while for final state hadrons a similar role is played byparton fragmentation functions.    recently there have been several excellent reviews of pdfs @xcite, updating the early treatises of pdf’s in refs ; however, there are many aspects of hadron structure that are currently not understood well, or at all, either theoretically or experimentally. in this review   we will attempt to answer the question " what do we know and how do you know it?"the purpose of this topical review is to give a current " snapshot" of the status of our knowledge of both unpolarized and polarized
the site of the rapid neutron - capture process ( the so - called r - process ) nucleosynthesis, the site of which is not known, is likely to be associated with explosive phenomena.   neutrino interactions play a very crucial role in the dynamics of core - collapse supernovae and in the n / p ratio of the rapidly neutron - captured nuclei, @xcite, which determines the isotopic yield of the r -process nucleosynthetic process. here   i briefly discuss our recent work on the measurement of antineutrino scattering off protons in a water cerenkov detector using low - energy beta beams at 0.0.25 cm2 using the weak magnetism form factor as a covariant matrix element for the reaction @xmath0.
the performance of a wireless network is a consequence of three factors  the hardware, the network protocols and the network topology.   for some networked systems, like the wireless mesh networks, the topology can be controlled rather easily through the medium access layer, and it is thus practically possible to optimize the topological of the network. in this work, we investigate a scenario of static agents ( sensors, individuals with wi - fi devices, etc. ), embedded in space, joining and leaving the system ( so called " churn " ). from these starting points,   we evaluate different simple attachment strategies to optimize several network - structural quantities, capturing efficiency of communication, scalability and robustness to failure. using the unit disc graph model of wireless networks   @xcite, we find that the most efficient attachment strategies are to let all agents within range be connected, and to limit the power consumption of each agent to a limited number of neighbors. by doing so  , we can increase the number of nodes in the network by controlling the network s topology, and reduce the energy consumption of new agents.
the study of nearby m dwarfs has become a major focus of research in recent years.   the precise measurement of their stellar parameters remains challenging, as the molecular species in their atmospheres mask the continuum and make direct spectroscopic modeling of their composition intractable. here  , we present a suite of new techniques for the measurement of the stellar properties of m dwarf stars using near - infrared ( nir ) spectra from the solar neighborhood @xcite. these techniques are based on empirical calibrations based on the photometric  dependence for m dwarf absorption in the nir, and are well - calibrated across a wide range of  and abbreviations, and have good precision ( @xmath9 dex in  = 1.0  0.5 in  ).    the calibration is then used to construct empirical models that can be applied to single stars, and the results are compared with those derived from abundance measurements of associated stars. by combining the accuracy of the calibration with the precision of the observed spectra,   these models can be used
glueballs, being composed of pure gluons in the limit of no quark fields, have attracted much attention since the theory of the strong interactions, quantum chromodynamics ( qcd ), was founded in the late of 1970s.   estimates of glueball properties were obtained in a variety of approaches, ranging from model analyses @xcite, quenched lattice qcd ( qlqcd)@xcite and unquenched Qcd ( uqlqcd ) simulations to qcd sum rule calculations @xmath0. here  , we show that the stability and consistency of the subtracted sum rule for the scalar glueball can be obtained by using a systematical semiclassical expansion of the background instanton fields in the instanton liquid model of the qcd vacuum @xcites.    the results are found to be in good agreement with different unsubtracted sum rules ( uss ).. the results of the ssr and ussr calculations are compared with those of the gaussian sum rule ( gsr ) calculation @xmrqcd.
the cfh optical pdcs ( cop ) survey contains approximately 650 galaxy redshift measurements ( from 6 nights of cfht time ) towards more than 10 pd clusters at a mean redshift of 0.4.   we have also obtained r  band photometry at the cfht for these targets. in this work  , we have combined our r - band data with the published pdc   photometry in v and i. this combined data set is allowing us to study the dynamical and morphological status of optically selected clusters of galaxies by comparing them with the enacs ( eso nearby abell cluster survey ) and the canadian network of observational cosmology ( cnoc ) samples. due to the relatively low number of galaxies,   it is difficult to directly compare the results of these two surveys. however, we are able to provide evidence for galaxy morphological segregation in clusters : early type galaxies tend to occupy denser environments and/or are preferentially found near the cluster centers.
we investigate the diffusion - limited -aggregation ( dla ) process on a two - dimensional directed small - world ( sw ) network, in which the directed links correspond to the directed irreversibly jumps and the node is regarded as the lattice point of the real space.   we find that the clustering exponent @xmath0 serves as a structural parameter controlling the spatial length of the long - range connections in the directed sw network. for the first time  , we show that the diffusivity of the network is controlled by the number of rewiring connections rather than the distance between the rewired sites.. the results are consistent with the results of previous studies of the diffusion model for the formation of self - organized fractal patterns on metal surfaces.
the origin of the onset of ultra - slow dynamics in glassy systems, and in particular, glass - forming liquids, remains a murky subject, with many competing ideas and tantalizing clues as to underlying causes.   recently it has become increasingly clear that dynamical heterogeneities, regions of atypically fast dynamics that are localized in space and time, are intimately connected to the phenomenon of glassiness, becoming increasingly important at lower temperature scales towards and below the glass transition temperature @xmath0 @xcite. here   we propose a coarse - graining procedure to explore whether a link can be made between molecular dynamics ( md ) simulations and kinetically constrained models ( kcms ) of Glassiness. using the local mean - square displacement ( msd ) in a suitably defined box to define a spin variable, we find that evidence of dynamic facilitation becomes much stronger at longer times of order , than at earlier times of orderedness . with appropriate choices of time and lengthscales  , we also find a clear mapping from our md simulations onto a kcm similar to the 1-spin facilitated fredrickson - andersen ( fa ) model
the voronoi cells are the local structural motifs of equal - sized bead packings obtained from experiments and simulations.   they are defined as the portion of space closest to a given bead center than to any other in the packing. for each bead,   the volume @xmath0 of such cells is considered as the only parameter that identifies the local structure. in this paper   we analyse the distribution of such volumes showing that it is very well reproduced by a kgamma distribution using experimental data sets of bead configurations from the database on disordered packings @xcite which contains structural data from experimental sphere packings collected by x - ray computed tomography ( xct ).    remarkably, this functional form is retrieved in a wide set of very different systems from idealized hard spheres to glass beads in water.
the direct superconductor - insulator transition ( sit ) at zero temperature in 2d systems is a well - known phenomenon.   however, recent experiments on homogeneous lead and bismuth films, which exhibit a transition from a superconducting to an insulating phase as a function of thickness, have led to the question of whether there is a low - temperature metallic state which is intertwined in such a sit. here   we review the literature on the role of dissipation in the occurrence of a non - superfluid metallic phase in close proximity to the super conductive phase.
digital in - line holography is a widely used tool for 3d imaging in severe experimental environments.   the common - path geometry of a classical in - lines holographic set - up makes it possible to perform quantitative3d imaging with a limited number of optical accesses and relative immunity to variations in the experimental conditions. however, this device is limited by the signal to noise ratio of the diffraction pattern ( i.e. the object signal to background noise ratio ) of the diffusion pattern, which prevents the detection of particles less than 5 @xmath2 in diameter with a unitary magnification configuration. to improve accuracy, while keeping ease of use of the experimental set -up, one can consider optimizing both the experimental and the data processing design.    here, we propose a modification of in -line holographies involving a selective 4-f filtering stage. 			 \documentclass{minimal }   \usepackage{amsmath }  =  xmath0.049   0.0004 ; n = 2 ; p < 0.05  . the optimal filter design is discussed through a crmer - rao lower bounds analysis.
we have carried out a medium deep near - infrared survey of galaxies, covering a large area and complete to @xmath14 mag. using published redshifts  , we construct the local infrared luminosity function ( irlf ) of galaxies and compare it with other, independent measurements.   the results show that the observed number - magnitude counts of galaxies are not affected by the mix of galaxy types or uncertainties due to evolution, compared to other wavelengths. however, the faint - end slope of the local irlf is weakly fainter than the bright - end of the irlf, which affects the interpretation of the count. in this first paper of a series,   we introduce the observations and data reduction of the survey and then present the results of a study of the morphological type - dependence of the optical lf, color - magnitude relations for field galaxies and the bivariate optical / infrared lf.
quantum information theory is an area of scientific investigation that has witnessed an enormous progress in the last decade.   the application of quantum information tools to the characterization and quantification of quantum entanglement has proven useful to tackle questions and improve our understanding in the investigation of strongly correlated systems and quantum phase transitions. in this paper   we exploit these tools to tackle another important problem in condensed matter physics : the determination and characterization of exact ground states of cooperative systems characterized by the property of being in the form of a fully factorized, tensor product of single - particle pure states, with no quantum correlations between the individual constituents. using the direct product - state ansatz method of kurmann, thomas and mller, we show that the existence of totally factorized ground states in quantum many - body systems can be achieved by adopting a quantum monte carlo numerical method based on the density matrix renormalization group ( dmrg ) algorithm. for the first time  , we demonstrate that this method can be applied to the study of quantum spin chains as natural information carriers and distributors, able to realize tasks such as quantum state transfer and storage, possibly with maximal fidelity in chains with suitably engineered couplings and dynamics
the morphology of satellite galaxies is an observable parameter that is directly related to the formation and evolution of galaxy.   the purpose of the present paper is to study the relation between the morphology of satellites and the local environment such as the host morphology and background density. using the large - scale structure sample ( lss ), dr4plus, from the new york university value - added galaxy catalogue ( nyu - vagc ), we used large and homogeneous morphology samples made by both visual and automated classifications. in this study, we show a tight correlation between the host and satellites morphologies. for the host sample,   our host sample is dominated by the @xmath2 galaxies, and their satellites are fainter by about two magnitudes. at the same time, for the satellite sample, we find that the satellite morphology is more likely to be early type for brighter galaxies than for the typical bright galaxies since the satellite system is hosted by very small and localized systems with a size of less than 1 mpc.
we examine whether there exists the relation between spinless massive particles coupled with three dimensional einstein gravity and the lorentzian version of the noncommutative field theory.   it is known that the 2 + 1 dimensional noncommute scalar field theory in the lie algebraic non commutative spacetime possesses an @xmath4 group momentum space. since it has been reported in @xcite that spinless huge particle coupled with the two - dimensional gravity possess an@x math4 group trajectory, the lorenstzian extension of theNonCommutative Field Theory might give the quantum dynamics of such spinlessmassive particles in 2 +1 dimensional e Einstein gravity. in this paper  , we show that the statement  spinless Massive particles in2 + 1 dimensionally coupled with 3d einstein gravitational field possess an #@xmath3 group momentumspace " is correct only when masses of the particles are positive and the total energy is not over @x maths5.
the globally coupled map lattice ( gcml ), a system of identical maps coupled via their mean field, has surprisingly rich clustering phases in the space of the nonlinearity parameter and the coupling. in the ordered two - cluster phase,   gc ml exhibits a posi - nega switch between clusters of synchronizing maps controlled by external inputs.   furthermore even in the turbulent regime there emerges some hidden correlation which was first observed as the violation of the law of large numbers in the fluctuation of the mean field in the time series@xcite. however, neither the reason why there occurs complete swapping of the maps between clusters in the 2nd cluster phase nor the global feature of the turbulent phase has been elucidated so far. in this article   we revisit gcML and show that there is a natural mechanism which guarantees the complete swapping from tightly synchronizing clusters to chaotic violent movements during the transient process.    we also perform an extensive survey of the turbulence regime of gcms and find that this regime has a prominent period three window and is full of periodicity remnants. for instance, a correlator analysis detects quasi - periodic clusters with high mixing rate among them almost everywhere in the
angular momentum transport in magnetohydrodynamic ( mhd ) turbulence driven by the magnetorotational instability ( mri ) is a key problem in accretion disk physics.   the standard theory assumes that the stress responsible for this transport is proportional to the local pressure, i.e., @xmath0. here, we provide an expression that describes the transport of angular momentum in shearing mhd boxes, based on a series of local numerical simulations carried out by @xcite. in particular, we are able to disentangle how the characteristics of the mhd flow depend on the various physical ( pressure, magnetic field, etc. ) and numerical ( box size and resolution ) factors. as a result  , we show that the results of these simulations can be used to estimate the value of the @x Math1 parameter for the saturated state of mri - driven turbulent mhd turbulence in astrophysical disks.
data presentation in astronomy has expanded beyond the traditional two - dimensional plots to include multi - variable analysis, immersive three - dimensional ( 3d ) models and exploratory analysis on a multitude of hardware platforms.   many forms of astronomical data can benefit from alternative forms of data exploration : data cubes can be rotated in 3d, fly - throughs of planetary landscapes can be explored, and all - sky maps can be examined.exploratory 3d presentations give users a different perspective on their data.traditional desktop and laptop configurations as well as hand - held mobile devices can be used as the hardware mechanism for these data explorations.the techniques can be employed in both research - level visualization and can deliver easy access to materials for education and public outreach.
differential atom interferometers are used for the measurement of gravity gradients and rotation rates, and for tests of the universality of free fall. in most cases, the fluctuations of the common phase, in general dominated by the effect of parasitic vibrations, wash out completely the visibility of single interferometry, but the correlation between the two output signals can be used to recover the information on the difference between these two interferometer phases.   we present an alternative method, that uses the correlation of the interferometric phases with an estimate of the vibration phase provided by an auxiliary classical sensor. using this method, we show that the differential phase of interferoscopes operated in a gradiometer configuration can be recovered without any biasing or an a priori knowledge of the noise distribution. as a result,   the sensitivity of the method is close to the quantum projection noise limit.
we present evidence that it is possible for measured data, which were spoiled by different types of noise, to separate two basic types of noisy noise and to measure their magnitudes.   the distinction between measurement noise and dynamical noise is based on the definition of the kramers - moyal coefficients from the recently proposed method @xcite. in this paper   we demonstrate that this method can be successfully applied to measured data of the chaotic shinriki oscillator, which are perturbed by different kinds of noise. using the theory of diffusion processes one is able to reconstruct from given data the underlying stochastic processes and to estimate the magnitude of the signal of the dynamical background noise.
the strong parity violation and the global system polarization of charged particles produced in non central relativistic nucleus - nucleus collision are studied by measuring the polarization of strange hyperons with respect to the collision reaction plane.   the effects of the parity violation are studied via three particle azimuthal correlations of charge particles : the first correlation is obtained from the direct measurement of the angular distribution of decay products of hyperons in the hyperon s rest frame measured at @xmath17 gev, the second from the directed flow of charged ions in the pseudo - rapidity range @x Math15 from star forward time projection chamber ( ftpc ) and the third from the fragmentation neutrons measured at x - ray diffraction ( xrd ) from star zero degree calorimeter - shower maximum detector ( zdc - smd ). for all three correlations the results are consistent with the theoretical predictions.
in a recent experiment the uptake of single dna molecules into the nucleus was studied by the group of m.  elbaum @xcite. in the present paper   we provide a computational and theoretical study to understand and interpret the results of this experiment.   for non - self - avoiding polymers, the effect of the bead on the uptake force can be obtained in a way much simpler than the original derivation, using a simple _ lattice chain _ model. if the _ persistence length _ of the polymer is @xmath18, the lattice constant of the equivalent three - dimensional lattice chains is@xmath19, which is called the _ uptake force_.    then we develop further this approach to take into account the role of the nanopore. when the dna molecule is linked to a bead, the entropic repulsion imposed by the shrinking dna segment   decreases as the bead length increases. 	 this result makes it necessary to reconsider the proposed kinetics of the uptake from the nucleus to the cytoplasm.
the fusion of colliding nuclei with neutron -rich/ -deficient content and at the extreme of isospin plane has attracted a large number of studies in recent years  @xcite.   this renewed interest is due to the availability of radioactive - ion beams that can produce nuclei at the edge of isspin  . theoretical models are very helpful in understanding the nuclear interactions at a microscopic level. in this study  , we compare as many as 12 proximity potentials with different versions for the calculation of fusion barriers for asymmetry in the neutron / proton content ( n = z+/z- ) of symmetric colliding nucleus. among them, four versions of proximity potential, three versions of potential due to bass and winther each and the latest potential based on ng and a modified version of the denisov potential are compared..the results show that the fusion barriers calculated by these potentials are not significantly different from those calculated by the experiments. however, the fusion barrier calculations are more sensitive to the size of the neutron or proton excess than the isSpin content.
we investigate the scattering properties of exactly - solvable time - periodic complex potential wells, which show the rather exceptional property to appear  reflectionless _ and to conserve  the energy of the transmitted particle at any energy.   this means that the particle, in addition to not being reflected from the potential well, does not exchange energy with the photon field, i.e. the scattering matrix elements to all the floquet channels vanish.    the existence of reflectionless and energy - conserving potentials periodically - oscillating in time has not been predicted yet, but is shown to be possible by application of the darboux transformation for the time - dependent scrhdinger equation. a quantum - optical analogy between the well - known problem of bragg scattering of light waves from a diffraction grating under grazing incidence and the scattering dynamics of a non - relativistic quantum particle from a periodic time - varying potential well or barrier is established.
the existence of a homogeneous cooling state ( hcs ) and two temperatures in a binary mixture of inelastic hard spheres is demonstrated by molecular dynamics ( md ) simulation for a system with different kinetic temperatures for each species but a common cooling rate.   the dependence of the temperature ratio on mechanical properties and state conditions is found to be in good agreement with predictions of the enskog kinetic theory except at high density and strong dissipation, which show significant quantitative deviations from the thermodynamics of the latter.the hcs can be given a time independent representation by transformation to suitable dimensionless variables @xcite. in this form it is similar to the steady state obtained for _ homogeneously driven _ granular fluids when the system is locally driven.
a detonating failed deflagration ( dfd ) model is proposed for the formation of type  ia supernovae.   the model is based on a single - degenerate scenario in which the ignition of the degenerate matter takes place in the core of a chandrasekhar - mass white dwarf, a remnant of the final merger phase that does not result in an instantaneous explosion. erytheoretic and numerical studies of the conditions prevailing in the white dwarf s core just prior to the thermonuclear runaway are used to define the initial conditions for multidimensional hydrodynamic models of the ignition process. using a generalization of our early exploratory study ( *???   * hereafter pcl ), we show that the inhomogeneities in the outer ejecta layers of the model are due to the large scale perturbation of the surface stellar layers induced by an off - star collision with the surrounding stellar layers. at the same time, the model also shows that the interior of the exploding white dwarf is dominated by hydrogen - rich material, which is formed from the fusion of the two types of energy - rich materials present in the center of the redox - active white
the cognitive pilot channel ( cpc ) has been suggested to provide frequency and geographical information to secondary users ( sus ), assisting them in sensing and accessing the spectrum.   the on - demand cpc transmits the information only at the request of a su terminal. to establish an effective cpc network, a multi - hop distributed cognitive radio ( cr ) network scheme is required. here  , we investigate a spatially and temporally dynamic game framework which takes into account the state variation of the primary users ( pus ) as well as the multi - stage property of the cr networks. using thresholds to separate the sus logically into different layers, we allow sus at each level to play a game against other users by choosing the optimal route. in simulations, we observe that with the presence of a primary user ( pu ), the sus deviate from their original routes to avoid collisions with the pu.    the proposed algorithm minimizes the interference with the pus and packet delay along the routing path.
compact radio sources in nearby starburst galaxies often appear to be supernova remnants ( snr ).   this behavior suggests a connection between supernova activity and the near - infrared (  ) line emission in starbursts, which is supported by the tight correlation between the radio 6 cm and the @xmath0 m emissions.. however, there are indications of some complexities in this relation. here   we present the results of a high - resolution  imaging survey of the nearest starburst galaxy, m82, and the large magellanic cloud, ngc  253. using the nic2 and nic3 cameras, we have obtained images of both galaxies with a spatial resolution of 5pc and 4pc for m82 and ngc “ 253, respectively. from these images, we find that the bright  emission in m82 is not spatially coincident with the position of the radio snr, but rather comes from a population of compact snr older than the radiosnr.
neutron capture cross sections are important ingredients for nuclear research and applications.   a recent compilation of these cross sections is given in @xcite, which shows the thermal neutron capture cross section for a variety of nuclei across the periodic table. here   we take a critical look at the data and present an analysis of both the fluctuating background using random matrix - inspired means, and the aforementioned anomalously large cases. in the latter case  , we base our discussion on the idea of a statistical doorway resonance which sits far up in energy but can influence the cross section in basically the same way that such doorways influence the parity violation, " sign " problem ", seen in the measurement of the longitudinal asymmetry of epithermal neutrons scattered by thorium, in the r - process of astrophysical significance.
we conduct a search for point - like behavior in arrival direction of cosmic ray events above @xmath0  ev in the northern hemisphere, using a skymap technique in which we evaluate our sensitivity using monte carlo simulated sources.   we find evidence for a dipole moment in right ascension ( ra ) at energies above@xmath2 ev for neutrons from cygnus  x-3, an x - ray binary within our galaxy, and a compact arrival direction excess at these energies would suggest neutral primaries.
damped ly@xmath0 ( dla ) systems are the only class of quasar absorption line systems that show 21-cm absorption against the background quasars.   their low metallicities, low dust contents, and low molecular contents are all consistent with properties expected of galaxies that are in the early stages of evolution. at redshift @xmath6,   dla systems have  abundances of 1/300 to 1/10 solar metallicity, which is consistent with them being young galaxies in the earliest stages of chemical enrichment. here  , we discuss some of the properties of these galaxies that may be helpful for planning future radio and millimeter observations.
sandpile models are the prime example of self - organized criticality ( soc ), in which a system with an absorbing - state phase transition is forced to its critical point @xcite, leading to scale - invariance in the apparent absence of parameters.   previous studies of fixed - energy sandpiles ( fes ) reveal that they exhibit a phase transition between an absorbing and an active state as the particle density @xmath5 ( which is the temperaturelike control parameter ) is increased beyond a critical value@xcite. until now  , all quantitative results on fes have been obtained from simulations. in this work   i develop @x Math6-site approximations for a one - dimensional sandpile model, and analyze the results using the suzuki s coherent anomaly method ( cam).this represents the first application of the cam to a model representative of the class of absorbing -State phase transitions in systems with a conserved density @xfite.
we present a statistical analysis of the bit - flip error threshold for qudit - based quantum memories using monte carlo simulations.   we use abelian quantum double models to estimate the maximum amount of errors a system of @xmath0-level quantum systems ( qudits ) can sustain while still being able to reliably store the encoded information. in the spirit of the approach used to estimate error resilience of fault - tolerant systems pioneered in refs.,   @xcite for qubit systems, we present a mapping of this statistical analysis to classical potts - spin models that can be seen as the natural extension of boolean variables to @x Math0 states.    this allows us to numerically calculate the bit Flip error threshold and its dependence on the dimensionality of the qudit dimensionality, with both upper and lower theoretical bounds for the threshold. by fitting the model to a statistical mechanical potts model, we find that the error threshold depends on the number of qudit spins in the system, the computational basis of the spins, and the level of topological protection provided by the quantum annealing device. at the same time, we show that the experimental results are consistent with the results
the influence of disorder on antiferromagnetic ( af ) order and the mott band gap in correlated electron systems is studied using a finite temperature determinant quantum monte carlo method.   we employ the hubbard model in the presence of different types of disorder, i.e., mobile scatterers, mobile carriers, and homo- or heterovalent dopants. to obtain approximation - free results for finite lattices, we use a new method based on a mapping of the interacting electron problem onto a quasiexperimental quasi - classical problem using auxiliary ising - type spins. as a result  , we find that the af phase diagram and the spin gap are significantly affected by the degree of disorder in the system. with the exception of the case of single - hole doping,   the effect of other dopants on af order is not significant.
the schrdinger equation for the description of well isolated resonances in small quantum systems is now extended to include the interaction of the states of the system with the environment of scattering wavefunctions into which the system is embedded.   the non - hermitian quantum physics is an expression of the fact that the system considered is really open and that the interactions between the state and the environment are not mediated by the single individual states.
ddo68 @xcite is an extremely metal - poor dwarf galaxy with a nebular oxygen abundance of 3% of the solar value.   it is an outlier on the mass - metallicity ( m - z ) relationship, as it is overly massive compared to the other known systems with comparable metallivity. here   we show that the high - density ( hi ) mass of ddo68 is four times larger than that of the bcd galaxy izw18@xcite, and 3 orders of magnitude larger than those of leo p @xcites. using both the archival hubble space telescope ( hst ) and the robert c. byrd green bank telescope ( gbt )  , we find that the hi morphology of d do68 is significantly disturbed.  in addition, we have discovered a previously unknown, gas - bearing companion system that is connected to dDo68 by a bridge of low surface brightness hi gas. taken together,   these lines of evidence suggest that d Do68 is undergoing an interaction or accretion event ; this may support the infall hypothesis.
the analysis of neural signals seeks to " translate " any set of neural impulses into a language we understand, but as the neural signals elicited by the same stimulus are never exactly alike, we need a quantitative means of determining when two neural signals serve the same purpose.   spike metrics have been successfully used to quantify variability in data and characterize neural coding in the visual, auditory, olfactory, taste, and electric sensory systems using data from isolated cell electrophysiology. here  , we propose a spike metric consistent with the rate - coding hypothesis of spike generation that has all of the desirable properties of an @xmath0 norm for comparison of two spike trains, and embeddings of spike trains using this metric in euclidean space with substantially less difficulty than they do for any other value of the @x math0 norm.
compact groups are small systems of several galaxies in a compact configuration on the sky.   they are prime locations for investigations of the dynamical evolution of galaxies, and have been the subject of much research over the last two decades. despite their name,   compact groups have received less attention than other types of galaxy groups, and there is growing interest in them as a source of evidence for dark matter. here   we review the history of the study of compact groups and discuss some of the recent advances in our understanding of their evolution.
the occurrence of modulational instabilities ( mi ) in the discrete nonlinear schrdinger equation ( dnlse ) is studied in the presence of non - local long - range hoppings and interactions in the nonlinear hamiltonian lattice model @xcite.   the effects of the mi are investigated in the context of the experimental observation of the onset of mi in nonlinear waveguide arrays and in the case of ultracold bosons in optical lattices.
the localization of energy implies the use of various energy - momentum complexes, including the prescriptions of einstein, landau and lifshitz, papapetrou, bergmann and weinberg.   all of these prescriptions have a drawback : the calculations are restricted to quasi - cartesian coordinates. on the other hand, mller @xcite proposed anenergy - momentum complex which enables one to calculate the energy distribution in any coordinate system and not only in quasi - Cartesian coordinates.in this work we have implemented mller s formalism to evaluate the energy distributions of an exact solution for a static massless scalar field minimally coupled to gravity in @xmath0 dimensions. using the mller's formalism, we have calculated the energy density for a geometry given recently by daghan and bilge ( 2014 ) in @Xmath0-dimensions.
the twist  two and twist  three operators in the operator product expansion ( ope ) of the nucleon s second spin dependent structure function @xmath0 are renormalized on the lattice  @xcite.   the results are compared with the lowest non  trivial moment of @x Math0, and with the twist   three contribution in (  ), which is also known as the wandzura wilczek contribution.
experimental observations of increased collective flow in ultra - relativistic heavy ion collisions at cern sps and bnl rhic, as well as theoretical considerations @xcite suggest that the quark - gluon plasma ( qgp ) is nearly a perfect fluid with very small viscosity. studying the entropy development of qgp systems provides an important aid in finding the critical point of the phase transition between qgp and hadronic matter.   we have used the mit bag model equation of state ( eos ) to study the evolution of the entropy of the qgp system in a fluid dynamical ( fd ) model based on the particle in cell ( pic ) method adapted to ultra - reliabatic heavy ion collision simulations. using the fd model, we find that the entropy increase due to numerical viscosities of the method exceeds the one obtained in 1 + 1 and 2 + 1 dimensional models with smaller cell sizes, and it is somewhat below the entropy rise of 6 - 24 %, obtained in those models due to physical vis cosmosis.
we study a process known as pair contact process with diffusion ( pcpd ) which has been reported to be possibly in an independent universality class using an alternative order parameter.   the model is studied by nonperturbative functional renormalization group and it is found to be in directed percolation ( dp ) Universality class. on including corrections to scaling of ratio of pair density and particle density, the critical density decay exponent is @xmath5 independent of diffusion constant. however, if the isolated particles are frozen, this reduces to pcp which belongs to dp university class.
the energetic gamma - ray experiment telescope ( egret ) has contributed enormously to the list of high - energy gamma -ray point sources.   the third egret catalog ( @xcite, hereafter h99 ) contains 271 point sources exhibiting significant flux above 100 mev. besides a single solar flare, the large magellanic cloud ( lmc ), and a probable association with a radio galaxy ( cen a ),   170 sources remain unassociated with known objects. in this study, we conducted a systematic and comprehensive survey of egret data from proposal cycles 1 - 4 in search of evidence of short - term flux variability above 100Mev.. six catalog sources were found to exhibit variability on one- and two - day time scales : four are unidentified, one is a flat - spectrum radio quasars ( fsrq ), or one is an unknown bl lac object. for the unidentified sources that display evidence of flaring, monte carlo simulations were performed to determine the probability of such fluctuations assuming intrinsically nonvariable sources. in addition, two transient non - catalog excesses and one non - Catalog sub - threshold repeating source were also identified. while the limitations of this study are discussed
the muon - to - electron conversion experiment at psi has set stringent upper bounds on the rate of lepton flavor violation ( lfv ) in various nuclei, thus setting stringent limits on the mechanisms of conversion and on the underlying theories of the process.   the experiments have been undertaken with negative results in the neutrino sector, but this is not the case for the charged lepton sector, which may receive contributions from physics beyond the standard model. in the present paper   we analyze non - photonic mechanism of coherent -conversion using improved values of hadronic parameters and extend our previous analysis made in previous papers including all the possible contact terms contributing to conversion. to this end we evaluate nucleon form factors for the heavy quark currents and take into account contributions of heavy vector mesons.. finally we update our previous boundaries on the @xmath13 4-fermion contact interactions and derive new ones from the experimental data on conversion rates in different nuclei.
the cryogenic dark matter search ( cdms ii ) recently announced the observation of two signal events with a 77@xmath11 confidence level and additional two events just outside the signal region border of the inelastic dark matter ( idm ) model @xcite.   these two events with small recoil energies suggest that the mass of dark matter is smaller than 100 gev with si cross section @xmath14 o(10@x Math15 ) pb which could escape other experimental constraints. here  , we present a detailed analysis of the recent dama, cdms results motivated by the neutrino constraints on the dark matter - nucleon cross section in the sun and the earth. for the sun,   the capture rate for both inelastically spin - independent ( isi ) and inelastically spin - dependent ( isd ) dark matter in the halo is about 1.5 times higher than for the light elastic dark matter ; however, this is not sufficient to account for the observed signal events from the dama experiment.    for the earth, the capture rates for isi and isd dark matter are about 0.2 and 0.4%, respectively.
the photospheric  phase spectra of type  ib supernovae ( sne  ib ) have been compared with synthetic spectra that we generate with the fast, parameterized, supernova spectrum  synthesis code, synow.   the spectra are obtained by comparing the observed spectra with those generated using the synow software. in this paper   we show that the observed sn  ib spectra can be interpreted by means of a direct analysis of the chemical composition of the ejected matter and the velocity of the he  i lines at the photosphere as determined by the fe  ii lines. for the first time, we find that some of the observed features such as the presence of hydrogen lines and the homogeneous appearance of the spectral data are not due to ad hoc overpopulations of the highly excited lower levels of the h2o lines but are due to line identifications of the upper level of the visible he   i lines caused by nonthermal excitation and ionization of the decay products of radioactive @xmath1ni and @x math1co. the results are discussed in detail.
short gamma - ray bursts ( sgrbs ) are believed to be caused by the merging of two compact objects, such as neutron star   black holes ( nss ).   they are rare events, and the sampled volume is so small that the final detection rate is low @xcite. despite these limitations, a few strict estimations of the detection rate of an event simultaneously in both windows, based on actual observation, have been done using theoretical modelling and population synthesis hypotheses. however, their selection of data might bias somewhat their result. here  , we show that the most recent observations of the short grbs have provided a new estimation rate for the detection of these events, which is much higher than the one obtained so far from theoretical modelling.. this rate is based on the assumption that the burst is due to the merger of two binary neutron stars ( bns ), which can be detected by advanced virgo and ligo detectors, and it is also supported by the fact that the current methods for detecting gravitational waves ( gws ) are not able to detect them at the same distance as the mergers.    the results show that there is no reason to believe that the observed rate is
precise determination of @xmath2, a parameter of the cabibbo - kobayashi - maskawa ( ckm ) matrix, is an important goal of many experimental studies.   the current experimental limit @xcite@xmath3 is based on measurements of the beauty hadron decays produced at the @x math4 resonance ( by argus and by cleo ii ) and in @x Math5-boson decays ( by the four experiments at lep ). to fully exploit the anticipated experimental improvement  , the theoretical description of the @Xmath1 decay must be known with comparable precision. for this purpose   we have recently calculated the two - loop corrections to the differential semileptonic decay width of the #1 quark at maximal recoil using the previously obtained value at zero ( minimal ) recoil. in the present paper  We describe the methods employed in that calculation.
we propose a new tripartite continuous variable entangled state ( ces ) @xmath0, which is the generalization version of the old triparite ces@xmath3.   this generalization is not trivial. as tripartites ces  , we find that it can play as the continuous base in hilbert space of square - integrated property, after checking its completeness and orthogonality. by virtue of the technique of integration within an ordered product of operators ( iwop ), we derive new quantum mechanical states possessing the completeness relation and orthotonic properties of the existing tripartitic ces @x math0. for example, the fock state and the coherent state are both complete, and then by decomposition of the gaussian integration operators within normal ordering, we obtain two mode coherent entangled state @x Math0:={\left\vert z \middle\rangle\middle\langle z\right\vert } and two mode idealized einstein, podolsky and rosen ( epr ) state @ xmath1:=1 \label{two}\ ], which possess the same properties as the multipartite c
the kinematics of globular clusters around the central giant elliptical in the virgo galaxy cluster, m87 ( ngc 4486 ), are investigated using published radial velocities for over 200 globular clustering candidates.   we find that the velocity dispersion and rotation velocity both as a function of radius and an estimate for the dimensionless spin parameter @xmath8 for the galaxy are well within the range between 1 and 5 effective radii ( r@xmath0 ). at the extreme radius,   the radial dispersion is more variable than expected, and the rotation velocity is much larger than expected due to the presence of multiple accretion of stars in the cluster. here  , we extend the results of our previous study by extending the sample to a region between 2 and 5 r@Xmath0.    we show that the radial distribution of the globular groups is very similar to that of the galaxy itself, with the exception of the large over  abundance of globules around the center of the cluster which is observed in the region between ~2 and ~5 r@ xmath0 ; this suggests a formation via two massive gas  rich galaxies. on the other hand,
the elastic constants and phonon - dispersion relations for the heusler - type intermetallic compounds fe@xmath0val and fe@Xmath0vga have been calculated using density functional and density functional pertubation theory within the generalised gradient approximation.   the results of the calculations are compared with experimental data, and the mechanical behaviour of these compounds is predicted using the modulus of elasticity as a function of the hankel - functions in the ground state and the valence bands based on the all - electron linear muffin - tin orbital method@xcite in a full - potential ( fp - lmto ) implementation.the results show that the elastic constants of both compounds are in the range of 0.1 to 0.5 kj / mol, and they are found to be significantly different from the experimental values due to the presence of a pseudo gap in the density of states in the vicinity of the fermi level. 	 the phonon dispersion relation between the two regions of the lattice shows that the transition from a monodisperse to a single - crystalline state is caused by the formation of a large number of hydrogen atoms in the interstitial
the interplay between instantons and monopoles in non - abelian gauge theories is well known, but the role of calorons in this interplay is less well understood.   we present a new method for constructing multi - caloron solutions from the atiyah - drinfeld - hitchin - manin ( adhm ) - nahm fourier construction based on taking instantons in @xmath11, which periodically repeat in the time direction, and then superpose them by simply adding the gauge fields of the corresponding instantons. to deal with the gauge singularity of one instanton, when adding the field of the others, one has to smoothly deform the gauge field of its constituent instantons to vanish near the gaugesingularity. as a consequence,   the collective gauge field shows a narrow and steep enhancement at the location of the would - be dirac string, which is not seen in gauge invariant quantities, but is instead described in terms of self - dual dirac monopoles, which decay exponentially outside the cores of the constituent monopoles. using the density functional theory, we show that the dirac strings can be used to study the interaction between these two groups of particles
the mass of the black hole ( bh ) at the center of ngc  4151 is determined by using a combination of optical spectroscopy of stellar absorption lines and orbit superposition modeling.   the results are compared with those of several other techniques that have been developed to determine the bh mass of active galactic nuclei ( agns ), including the reverberation mapping technique, which has been used to estimate the mass of sgr  a, the most tightly constrained black hole in the universe.
the signum - gordon model of non - abelian gauge fields in the presence of external charges is a very useful theoretical laboratory in which we can study various aspects of nonlinearity of field equations.   recently we have shown that the signum-gordon model is nonlinear in the case of two identical charges, and that the charges are totally screened by a cloud of the scalar field. in the present paper   we corroborate these results by solving the two dimensional case using a formal mathematical connection with the planar electrostatics. for a single charge, we find the exact shape of the screening cloud and derive the integral formula for the force between the charges. for two or more charges situated not too far from each other,   the screening is much more difficult. in this case, we show that the screening completely vanishes when the distance between the point charges exceeds a certain critical value.
we present a numerical code for solving the riemann problem in relativistic hydrodynamics with non - zero tangential velocities.   the code is based on a new formulation of the numerical scheme for the perfect gas equation of state, and it is used to study the stability of corrugation instabilities occurring in solutions of the riomann problem for ultrarelativistic and perfect gas equations of state both for the right and left sides of the solution. by means of this code   we show that the surface of the shock wave in the solution becomes unstable when the velocity tangent to the contact discontinuity is less than 0.1 km / s, and that the frequency of such instabilities increases with increasing velocity. however, the stability does not have to be the same for the rarefaction and shock waves, or for the rest - mass density and the specific internal energy.
closed - orbit theory has been used to describe the photo - absorption spectra of hydrogenic rydberg atoms in crossed electric and magnetic fields.   it provides a semiclassical approximation to the quantum response function  (  ), which splits into a smooth part and an oscillatory part of the form @xmath9 where the sum extends over all classical closed orbits starting from the nucleus and returning to it after having been deflected by the external fields. in the present paper   we show that the novel framework can be extended to the crossed - fields situation, and we clarify some misleading conclusions arrived at in @xcite. for systems with and without a rotational symmetry,   the closed - orbit formula  is shown to be suitable for quantization by harmonic inversion.
a widely used trial correlated wave function is the jastrow - slater  @xcite or feenberg   ( @xmath2 d~ ) form of the many - body hamiltonian, which is often used as a starting point for variational monte carlo ( vmc ) calculations of the electronic structure of periodic solids.   the accuracy of these calculations is entirely dependent on the trial wave function, however, and so the development of accurate wave functions is vital both in the accurate estimation of physical properties and in understanding how certain physical phenomena may be simply represented in the wave function.we present here, for the first time, a numerically robust, rapidly convergent iterative method which minimizes the variational energy with respect to a very general inhomogeneous form of this wave function using a complete treatment of inhomogeneity in the two - body correlation term for diamond and rhombohedral graphite. within acceptable computational demands on the montecarlo sampling,   we find that the optimal values of the three - dimensional model parameters for the optimization of the experimentally derived jastrows are found to be 1.5  kcal / mol for the one - body term @x
oscillatory behaviour is observed in a great variety of biochemical systems, over a wide range of time periods.   these oscillations have been modelled extensively, using both deterministic and stochastic frameworks @xcite. however, many processes display coherent behaviour over a population of cells, and this requires that the oscillations in the individual cells must influence each other. for coherent, collective behaviour ( such as intercellular signalling ),   some form of communication between the cells is necessary. in this paper   we will present an approach to the investigation of synchronisation in models of biochemical processes which are analytic and where the models are stochastically in nature. by using reaction systems as examples  , we will show the forms that the interaction can take, and what ` weak'means in this context.
the estimation of quantum states is one of the basic primitives in quantum theory.   this general task appears in several modifications and situations. here   we consider the following problem : let us assume that an apparatus is given, which produces for a given input @xmath1 the state@xmath4 where @x Math2 and @x math3 are known.. the task is now to estimate @x maths1 from a single copy of @xMath5.,we discuss how the results from the qubit case can readily be used to solve this problem.
massive compact galaxies ( smgs ) are among the most luminous and rapidly star forming galaxies in the high - redshift universe.   they are believed to be the precursors of local early - type galaxies at high redshift ( e.g., @xmath4gyr ), but how they first formed is not yet fully understood. a recent theoretical model for the formation of these compact systems predicts that massive, gas - rich galaxies at very high redshifts become unstable following a major merger event, triggering a short - lived starburst within the remnant. here   we investigate whether this model is compatible with the observed size evolution of the sub - mm galaxies, which have been imaged with hst in deep exposures, and test whether the different observed morphologies of the smgs can be fitted into the evolutionary sequence proposed by current massive galaxies formation models. based on their morphology and structure, we find that the sizes of our sample of sub-mm galaxies are remarkably smaller than those of their local counterparts, and that the star formation rates of these galaxies are in agreement with theoretical expectations. however, we also find that some of the observed sizes are significantly smaller than predicted by the theoretical model.
a lunar - based radio telescope would have two key advantages over ground - based observatories.   first, if located on the far side of the moon, the observatory would be shielded from terrestrial transmissions, both natural and human - generated. in contrast, the earth s ionosphere is opaque at wavelengths longer than about  30  m ( frequencies below about  10  mhz ). without a permanent ionosphere, the surface of themoon opens a spectral window that is entirely inaccessible from the ground, potentially to wavelengths as much as two orders of magnitude longer than those accessible from the Ground. here   we summarize key science that would be enabled by a lunar -based radio observatory.
we investigate the quantum statistical properties of the light generated in an off - resonant rydberg - eit scheme using cold rubidium atoms placed in an optical cavity @xcite.   we show that, under some assumptions, the system effectively behaves as a large spin coupled to the cavity mode and that the steady - state second - order correlation function of the outgoing light beam can be used to characterize the emission of photons out of the cavity. our numerical simulations suggest that the bunched or antibunched nature of the incoming light as well as its coherence time may be controlled through adjusting the detuning between the cavity modes and probe field frequencies.
tully - fisher ( tf ) studies of the relation between luminosity and rotation speed are often limited by the lack of precise inclinations for nearly face - on galaxies.   we have found that kinematic inclinations, derived from high - quality, optical kinematics data collected with integral field units, are sufficiently accurate and precise to construct a tf relation at inclinations as low as 15@xmath0 for a sample of 39 spiral galaxies meeting the criteria of andersen ( 2001 ) : galaxies appear Nearly Face - On ( @xmath10 ), are of intermediate type ( sab - sd ), with no clear signs of interactions, bars or rings, and are in regions of low galactic extinction. using our results  , we show that the tf relation is robust to systematic errors in photometric inclination and position angles ( pa ), and can be used to estimate the vertical component of the disk stellar velocity dispersion, which is favorable to the projected rotation speed.
the sub - millimetre common user bolometer array ( scuba  holland et al.   1999 ) on the james clerk maxwell telescope ( jcmt ) has resolved the far - infrared background light into discrete sources, which have been resolved into discrete radio sources with an optical magnitude, @xmath12, using a set of 47 microjansky radio sources in the hubble deep field. here   we use radio continuum followup to investigate the redshift distribution of these sources at 3@xmath9 rms limiting flux densities of 6mjy at 850 microns. from the observed ratio of sub - mm to radio continuum flux density, we estimate a redshift of ~1.5 kv for the majority of the sources, and find that none of the optically brighter radio sources are detected in the sub - Millimetre population. as the k - corrections ( corrections based on the redshifted spectral energy distribution - sed ) of the radio and sub - mjy flux density are opposite in slope, the ratio of radio to sub-mm flux density is quite sensitive to redshift. by applying this method to a sample of 20 previously observed sub -
we have used the infrared space observatory ( iso ) long wavelength spectrometer ( lws ) data from the us midcourse space experiment ( msx ) and the joint nasa / isas infrared telescope in space ( @xcite ) to determine the absolute stellar spectra of two bright, non - coronal k giant stars, @xmath0  tau and @x Math0  boo, in the 45170  @x math2 m region of the infrared spectrum.   the results show that the observed spectra are consistent with the uranus - mars framework for calibration of the iso lws at the longest wavelengths, i.e., 1.235 @xmath2 m, using a model atmosphere calculated by one of us ( dfc ) : @xaicite. however, these calibrators require long - wavelength extrapolations, as far as 300  =  2 m, of the observed values of the measured spectra, which are based upon the assumption that these calibrator stars are not attended by extensive chromospheres. on the basis of this assumption, we have found evidence for buried high temperature emission in the case of @x maths0  bo and @
the late - time acceleration of the universe has been confirmed by multiple cosmological probes over the last fifteen years.   the underlying cause of this acceleration, as well as its connection to fundamental physics, however, remains to be clarified. in this paper  , we present both perturbative and n - body methods for computing the nonlinear matter power spectrum for the neutrino sector of the cosmic microwave background ( cmb ), using data from the boss and desi spectroscopic redshift surveys, and the large synoptic survey telescope ( lsst ). while the effect of neutrinos at sufficiently large length scales can be studied using perturbation theory ; at smaller scales, matter clustering can be treated via n-body methods. with respect to the cmb,   our results show that the size of the dark energy density responsible for the acceleration is much larger at earlier times than at later times, and that the number of species involved in the clustering is much smaller than expected from the standard model. on the basis of these results, we propose a new model for the evolution of the early dark energy equation of state, which is consistent with the observed data.
the study of geodesic flows on negatively curved manifolds has been extensively studied both from the topological and the measurable point of view.   the goal of this paper is to provide explicit counterexamples to each of the results stated above, in the context of rank one manifolds. here   we show that the closure lemma of the poincar recurrence theorem can be applied to the case of recurrent geodesics defined on non - positively curved riemannian manifolds with rank one curvature. for a given rank one surface,   every vector in the set @xmath4 can be shadowed by a periodic geode, and there are ergodic measures with full support that are invariant by@xmath3. for any compact or finite volume negatively curved surface, then the closed lemma ensures that the periodic orbits are dense in the manifold. for surfaces with finite volume, if the surface is compact or with infinite volume, the closing lemma is not always applicable.
the determination of the shape of the quark - gluon vertex plays an essential role in the understanding of many important properties of the infrared behavior of qcd @xcite.   this vertex is in particular fundamental in the analysis of the origin of dynamical chiral symmetry breaking in the context of truncated dyson - schwinger ( ds ) equations. to cope with problem,   mainly two methods have been used : lattice simulations and ds equations. in both of these approaches, the landau gauge is the most convenient gauge because it is a linear covariant gauge that manifestly preserves lorentz invariance. from the analytic side, it is the only one that includes the symmetries of the curci - ferrari gauge for the vertices where the gluons lines are multiplied by transverse projectors. here  , we review the results of the complete one - loop calculation of the geometry of the vertex in @xmath0@xcite using this gauge.
quantum - jump - based feedback controls have been proposed to generate steady state entanglement in a cavity @xcite.   these two feedback schemes are markovian, namely, a feedback information proportional to the quantum -jump detection is synchronously used.. besides, these control scheme can also be used to suppress decoherence@xcite and prepare and protect entangler between the nuclear and electron spins by controlling the electron spin. in this paper, we study this problem by considering a nuclear spin ( as a qubit ) coupled to electron spin (as the other qubits ) that is exposed to its environment. using a quantum - jumped feedback control on the qubit 2, we show that a markovia feedback based on quantum -Jump can be used for the suppression ofDecoherence, produce entanglements and protect it.
the density wave ( dw ) theory, originally conceived by  @xcite and developed in a linear form by @xcite, has been commonly brought up to explain spiral structure.   one fundamental prediction of this theory is the presence of offsets between tracers of the different stages of star formation and evolution, as a result of the interaction between a spiral pattern with an angular speed that is nearly constant with radius, and stars and gas with differential rotation. here  , we investigate the effect of having ( and neglecting ) non - circular streaming motions, that is, of using a purely circular dynamic model to derive spiral pattern speeds from observations of color gradients. for models with a fixed pattern speed,   the radial tremaine - weinberg ( rtw ) method of co and hi data of several galaxies was applied to measure the spiral pattern speed @xmath5. in spite of having a real pattern speed which is constant with diameter, higher pattern speeds were measured at higher radial velocities than those at lower radius. on the basis of these results, we conclude that the dw theory is not applicable to the origin of spiral arms, bars, and rings.
we report on x - ray and optical observations in the field of one of the unidentified galactic gamma - ray sources with a hard spectrum, 2eg  j0635 + 0521.   the source is a single point source located within the error box of the egret source 2eg ( thompson et al., 1996 ). using the satellite italiano per astronomia x ( bepposax ), we observed a field centered on a region of unusually high x - rays hardness and brightness found in an X - ray survey of the monoceros supernova remnant and located within this field was previously viewed with the einstein s epr spectrometer. here  , we report on the identification of the source by combining data from the lecs, the combined mecs 2 and 3 detectors, and the pds. for the first time, we find that the source has an unusually hard x -ray spectrum with a spectral index near 1.5 and significant emission detected out to 40  kev. during the observation, we also find no evidence for pulsations in the x - Ray data over a period range from 0.030  s to 1000  s. these results suggest
we study stationary localized structures resulting from the balance of magnetic and ( both parallel and perpendicular ) thermal pressures, whose simplest description is provided by anisotropic magnetic tension balance ( mhd ).   isotropic mhd equilibria are classically governed by the grad - shafranov equation. in the present paper, we revisit this approach in the case of anisotropic electron and ion fluids where the perpendicular and parallel pressures are given by equations of state appropriate for the static character of the solutions. however, the mhd stationary equations, at least in the two - dimensional geometry, turn out to be ill - posed. as a consequence,   these equations require some regularization. as done in a similar context of pattern formation, an additional linear term involving a square laplacian   is introduced for nonlinear mirror modes which are not subject to the drift kinetic approximation. here  , we show that the gyrotropic pressures depend only on the local magnetic field amplitude that, as shown in the forthcoming sections, is specific for nonlogarithmic mirror modes. in this case, the parallel component of the equation is satisfied identically but the pressure balance equation is expressed in a vari
we propose a randomised feature selection algorithm for nonlinear feature selection based on estimating the statistical dependence between bootstrapped random subspaces of the dataset in rkhs.   the dependence estimation of random subsets of variables is similar to the approach of stability selection, which is extended through bootstrapping and carefully controlled feature set sizes. using this approach  , we find that the performance of the proposed algorithm is comparable to that of other kernel - based feature selection algorithms. by comparing the results of our method with those of several other algorithms,   we show that it is computationally efficient to estimate the dependence of the feature set size over a number of different subsamples of the data using bootstrap - based estimation.
we examine the question of whether the long - time residual of a current in an integrable system is saturated by the standard conservation laws and whether there is a secondary mechanism or perhaps even ` non - local conservation laws' which contribute.   we show that it is possible to saturate the residual, but the conservation law required is non - analytic in the natural local conservation Laws prevalent in the literature.. we also show that the conservation laws are not enough to describe the residual.
the fractional calculus has found many applications in several areas of science and engineering.   the nonlocal property of the fractional derivatives and integrals is used to model the processes with memory effect. in this work, we define the non - local derivative on fractal sets as a generalized riemann - liouville and caputo fractional derived from the continuous but non - differentiable functions which admit the local fractions. using the proposed method, we derive the new derivatives for the functions with fractal support. these new derivatives can be successfully used to derive new mathematical models by using the suggested methods.
the exact derivation of thermodynamic and structural properties for a homogeneous one - dimensional hard rod system ( tonks gas ) with first - neighbor takahashi - type interactions is presented.   the approach is motivated by the assumption that the equation of state ( eos ) for such systems is valid on a coarse - grained local scale. from the requirement of mechanical equilibrium, spatial variations of pressure and density can be calculated from the spatial variations in the external potentials of the rods at thermal equilibrium. to test this assumption,   we apply the method to hard rods in a uniform gravitational field and in a power - law trap using statistically interacting vacancy particles as quasiparticles. here  , we show that the sivp approach is a simple and efficient way to obtain exact density and pressure profiles for inhomogeneous systems, which generally is a difficult task for an interacting many - particle system.
spatial point patterns have important implications in epidemiology, population biology, ecology, and other fields, and have been extensively studied.   many univariate and multivariate tests have been proposed for testing segregation of two classes in statistical and other literature ( @xcite ). in this article  , we discuss the directional ( i.e., one - sided ) versions of the cell - specific tests of@xcite and propose new directional segregation tests for the two - class case. through extensive monte carlo simulations, we compare these tests in terms of distributional properties, empirical size and power, and performance with ripley s @xmath3 or @x math4-functions and pair correlation function, which are methods for second - order analysis of point patterns. using our data sets, we show that the newly proposed directional tests perform similar ( only slightly better in power ) to the cells - specific test of @xaite but perform better than dixon s cell - specifically tested tests. furthermore, we demonstrate that our tests answer different questions about the pattern of interest.
the evolving dark energy with an equation of state @xmath1 crossing -1 during its evolution was firstly advocated and named as quintom in ref.  @xcite. here   we propose a two - field quintom model with a scalar and a fermion which specifically we take to be the neutrinos and study its evolution of the equation of states. by means of an explicit calculation  , we show that the interactions between the two scalars do not affect the influence of the phantom - domination attractor behavior. furthermore, we find that the scaling solution dominated by the phantom field will be a late - time attractor in the absence of the interactions. in this paper   our studies also show that this class of models will provide some interesting possibilities of the evolution of these equations.
star - forming galaxies are confirmed @xmath0-ray sources, and their collective emission is likely to make a substantial contribution to the cosmic gamma - ray background ( cgb ).   the anisotropy of the cgb has recently been studied theoretically by a number of authors in order to look for signatures of various contributing sources such as blazars, galaxy clusters, type ia supernovae, and dark - matter annihilation. here  , we use a milky - way spectrum compatible with no gev excess and find the normal galaxy peak to reside at lower energies which allow for an almost contamination - free set of photons. this finding is consistent with our understanding of normal - galaxy clustering, and would be useful in a variety of ways.
compact binary systems are among the best laboratories to test general relativity and alternative theories, as well as the physics in strong field regime.   the existence of neutron star binaries ( hereafter nsns ), systems with a neutron star and a black hole ( nsbh ), and of two black holes ( bhbh ) has been dramatically confirmed by the advanced ligo detection of gw 150914 @xcite. here   we review the current status of the alv experiment, which will soon be able to detect the merger of two nsns up to @xmath5 480 mpc if it is face - on and in an optimal position with respect to the detector ( horizon ) or @x Math5 200 mpc for a source averaged over sky position and source orientation ( range ).
the abundance of dark matter in the early universe has been precisely determined by the wmap experiment.   however, the nature of the dark matter particles remains unknown. a sterile neutrino with mass of several kev and a small mixing with the ordinary neutrinos is an attractive candidate. if such a particle exists, it could explain the observed baryon asymmetry of the universe. here  , we show that the monochromatic line from dark matter decays can be observed by x - ray telescopes, but some important limits have been derived on the allowed masses and mixing angles. these constraints are based on different astrophysical objects, from virgo and coma clusters, to large magellanic clouds, to the milky way halo and its components, etc. for each object,   the dark - matter line should not exceed the signal, which can be measured by the los alamos liquid scintillator neutriniometer ( lsnd ) at the miniboone experiment. using this assumption, we derive the following limits : ( 1 ) the limit for the light sterile neutrosynthesis decay into one active neutrine and one photon, @xmath0,
we investigate the role of incommensurate magnetic states in metal  insulator transitions ( mit s ) in cubic lattices using the generalized kotliar   ruckenstein slave - boson approach.   we show that the paramagnetic mit is induced by a correlation - induced gap formation in the electron paramagnetic spectrum, which leads to the formation of a region of spiral metallic phase between paramagnetic metal and antiferromagnetic insulator in the square lattice at large values of @xmath1. for the case of half - filling,   the spin - spiral state is stabilized in the form of a wide concentration region with respect to the ground state thermodynamical potential.
the heisenberg chain is a typical spin system in condensed - matter physics. as a strong correlated system,   it can display rich nonlinearities induced by inter - spin interaction.   the typical nonlinear phenomenon is the solitary wave, that is a wave packet propagate without either energy loss and wave packet spreading. here  , we investigate the nonlinear effect of the collective spin excitation on the ferromagnetic order of a n - site xxz spin chain, which is rotated around the y - axis by an amount of magnitude @xmath3, and study how to manipulate a soliton excitation by this oblique magnetic field. our investigation shows that the switch between the bright soliton and the dark soliton is controlled by @x Math3, whose tangent is defined as the ratio between the z component and the x component of the magnetic field ; and at the turning magnitude referred to as the magic angle @x math4, the original anistropic chain becomes isotropic, therefore only an ideal spin wave is stimulated as an effective plane wave.
the tara experiment ( telescope array radar ) is a remote - station radio - wave observatory, based in malargue, argentina, and the northern hemisphere telescope array ( ta ) based in utah, usa.   the tara remote station aims to detect the charged component of extensive air showers ( eas ) by observing radar reflections from the core of an eas at radio frequencies using a radio - frequency echo doppler - redshifted radar reflection reflectance technique. here  , we present a monte carlo simulation of the expected signal characteristics of the t Tara remote station data, which are modeled by accounting for the effects of the shower properties and event geometry, atmospheric properties including local gas density, as well as the characteristics of both the receiving antenna and the ground detector. with the help of the gaiser - hillas prescription@xcite, we show that the expected signals are consistent with the observed spectrum of the cosmic ray background, and that the chirp rate can be characterized by several parameters, including the initial, final, and maximum detectable values of the radio -frequency " chirps ", which result from the separation of the charged particles comprising the down - moving air
the temperature dependence of the elastic constants of glassy materials does not appear to have been investigated extensively using the stress fluctuation formalism.   we present in this work such a study where we focus on the behavior of the shear modulus of two isotropic colloidal glass - formers in @xmath1 and@xmath2 dimensions sampled by means of molecular dynamics simulations at different temperatures. for each dimension, we find a correction term for the isothermal elastic constants to the born expression which involves the mean - square fluctuations of the stress, boltzmann s constant and the instantaneous value of a component of thestress tensor. with respect to the first dimension,   the correction term is consistent with the well - known pressure fluctuation formula for the compression modulus from the classical born theory. for the second dimension, however, the corrected term is more complex and the results are less consistent with those of the previous work.
quantum channels have attracted a lot of attention in the recent years.   recently some people show that provided the sender and receiver share prior entanglement, a higher amount of classical information is transmitted over pauli channels in the presence of memory, as compared to product and entangled state coding for quantum channels. in this paper, we show that if parties use a semi - quantum approach to entangler - assisted coding, a high amount of classic information can be transmitted over quantum channels with correlated noise, under the assumption that successive uses of the channel are represented by the tensor product of the operators representing one single use of thechannel, i.e., the channel is memoryless. here  , we derive a general expression for the entanglements - assisted classical capacity of quantum channels and compare our results with the product bell states and entangement - assisted codes for various types of paulian channels. using the quantum memory channels model, we find that the maximum capacity of the quantum channels can be achieved above the theoretical upper limit, when no quantum correlations are allowed, and we suggest another set of states for transmission of classical data.
quantum theory ( qt ) in hilbert space is time symmetric.   this is not so bad for the description of spectra and structure of quantum physical systems, whose states are ( or are considered as ) stationary, but it is particularly detrimental for decay processes and resonance scattering, which are intrinsically irreversible processes. to overcome this problem we propose a new axiom of quantum mechanics ( qm ) based on the hermiticity assumption : in qm " bra s " are not obtained by hermitian conjugation from " ket s" ( in our notation : @xmath19! ) and represented by two hermitia shadow fields.    we show that the formalism of ( a)cqt provides answers to questions raised in the previous section..1 the key to ( a]cqt providing answers to these questions is the fact that the klein - gordon ( kg ) equation can be treated as a non - hermitic one and the space of out - states is not obtained from the space between in - states by her mitigating the equations of motion by herMiticity conjugated states. here   we discuss the theoretical implications of this formalism
we have developed a method to forge progenitor / descendant links between galaxy populations at a constant comoving number density based on the cumulative stellar mass function  ( @xcite ).   we use cosmological simulations to infer the median mass and number density evolution of tracked galaxy populations by comparing the inferred evolution from simulated galaxy merger trees with that inferred from an assumed constant comving number density. using this method, we show that the observed median mass rank order of a tracked galaxy population is not always the same as the estimated median mass rate of a tracking galaxy population. in some cases,   the median masses of initially similar galaxy populations evolve into similar galaxies at different redshifts, while in others the median number density rates of evolving galaxy populations follow a different course depending on the initial number density of the tracking galaxy populations. these results are consistent with the assumption that the most massive galaxies at some redshift evolve into the mostmassive systems at some other redshift.
in this paper we discuss the mathematical aspects of the problems originating in the solution of nonlinear systems of hyperbolic partial differential equations.   these equations describe a large variety of physical phenomena, such as, gasdynamics, magnetohydrodynamics ( mhd ), shallow water equations, elasticity equations, etc. being nonlinear, these systems usually require numerical methods for their solution. here   we discuss several analytical and numerical solutions in the mentioned fields which illustrate the complexity of the selection problem and outline the methods of its solution.
low - mass x - ray binaries ( lmxbs ) have been a puzzle for theories of close binary evolution.   the existence of a low - mass star in a small orbit around a compact object ( neutron star  or black hole ) appeared to require a quite intriguing explanation concerning the evolutionary path followed by the progenitors of these systems. over the years  , three formation mechanisms have been put forward in an effort to understand the existence and evolution of lmxb : a common envelope phase, a supernova explosion, and a thorne-@xmath3ytkow object as the end product of a massive x - rays binary with a third component in a very wide orbit. in this paper   we explore the possibility that a simple evolutionary sequence can lead to the formation of l MXbs. even if the orbits of the primordial binaries are so wide that the two stars do not interact and a common envelop is not formed, the systems remain bound and the orbital separations decrease after the supernova explosions due to a kick of appropriate magnitude and direction imparted to the neutron star at birth. using population synthesis calculations, we show that the proposed evolutionary path is feasible and that the results are consistent with the
quantized vortices are among the hallmarks of superfluidity, and have been observed in the gaseous bose - einstein condensates of @xmath0  @xcite and @x math1 @xcite.   the aim of the present paper is to study the dynamics of vortex states with attractive interactions in three - dimensional axisymmetric traps. using a variational method, we find that the dynamical instabilities and split - merge cycles of the doubly - quantized vortex can be understood by using only three basis functions : the gross - pitaevskii ( gp ) equation, the bogoliubov theory, and the dipole instability. for a singly - quantitative vortex,   split - Merge cycles can occur in a pancake - shaped trap, whereas the split fragments immediately collapse in a spherical trap. in a cigar - shaped trapping  , the vortex splits into three clusters which revolve around the center of the trap, and undergo split - merging cycles before one or possibly more of them collapse. in the immediate vicinity of the critical strength of interaction for the vortex split, quantum fluctuations like the ones found in a 1d case
we investigate the impact of renewable energy on the amount of heat loss in an energy network, and how storage devices such as batteries can help mitigate this loss.   we model a dc network having random sources and sinks with a single slack node, and derive an explicit expression for the expected total heat loss that gives insight in how the optimal location of such a battery depends on the network properties as well as on the mean and variance of the external currents. considering the prototypical case of two batteries, we show in a static setting how the expected heat loss crucially depends upon the way the batteries share the load. using a control problem in which we allow batteries to share the loads dynamically, we find that the total expected heat losses can be reduced significantly if the load does not oscillate from one battery to the other.
we propose to use the full counting statistics of density fluctuations as a tool to gain access to the many - body nature of the ground state of a fermionic cloud in the bardeen - cooper - schrieffer ( bcs ) crossover regime.   our main result is a general expression for the particle number statistics of the mean - field bcs wave function. in the limiting cases,   the statistics allow a straightforward interpretation. deep in the molecular bose - einstein condensation limit the statistics are poissonian, i.e. that of independent pairs of atoms. on the bcs side of the crossover, on the opposite limit  , the fluctuations are strongly suppressed and reflect the particle - hole symmetry.
among _ ab - initio  molecular dynamics ( aimd ) simulation methods, the wavefunction extrapolation technique @xcite is considered to have good reliability and predictive power, especially for material systems with a small or vanishing band gap.   it combines results from previous molecular dynamics time steps to predict a good initial guess for the self - consistent field ( scf ) solution of the kohn  sham equation at the current md time step. in this work, we present a new scheme for the propagation of the wavefunctions from previous md time steps in the extrapolation using the apj alignment scheme proposed by arias, payne and joannopoulos, and the mead alignment scheme suggested by mead, and compare the results with those of several popular aimd simulation packages based on the plane - wave method. as a result, we find that the value of @xmath0 is most relevant to the number of scf iterations, and choice between the two wavefunction alignment schemes does not affect the prediction of the scf convergence criterion.
in recent works of lattice quantum chromodynamics ( qcd ), the static quark - antiquark potential is analyzed by the fourier transformation of the link variable @xcite.   these works clarify that quark confinement originates from an infrared gluon below 1.5 gev in the landau gauge. here, we apply this type of analysis to the calculation of the action / energy density distribution around a static quarks - antiquarks pair using the three - dimensional version of the lattice framework to remove the high - momentum components of the gluons field. because the flux - tube contribution to the action and energy density is rather smaller than the perturbative contribution, it is difficult to observe the formation of the flux tube in traditional approaches. however, by removing the high- and low - momentum gluones, we can clearly observe the flux tubes.
the three - quark ( 3q ) potential is one of the most fundamental and important quantities in quantum chromodynamics ( qcd ), and is directly responsible for the hadron properties.   we show the first result on the 1st excited - state potential @xmath1 in the spatially - fixed 3q system in su(3 ) lattice qcd   @xcite. to give a solution to the mystery of the gluonic excitation modes in the 3q systems, we investigate the gliophysics of the 3qs in the model - independent way.
the lacewing code is a new membership identification code for young stars that uses kinematics to identify members of nearby young moving groups.   it uses the six basic kinematic elements ( ra, dec, @xmath0, #, #1, #2, #3, #4, and #5 ) to predict probabilities of membership in 10 moving groups and 4 open clusters using the proper motion, distance, radial velocity, and spatial location of the star matched to those estimated for a group member at the same ra and dec. these metrics are combined into a single numerical goodness - of - fit value, which is then transformed into membership probabilities by creating a large simulation ( using 32 million stars ; ( *????   * riedel et al. submitted ) ) of the solar neighborhood of the sun.. the lacewed code is freely available at http://www.lacewing.org.
the three - family standard - like model in @xcite is a four - dimensional supersymmetric type ii orientifold model with the standard model gauge group as the gauge group and candidate fields for the three generations of quarks and leptons as well as the electroweak higgs doublets.   the model is not fully realistic, since it contains a quasi - hidden non - abelian sector which becomes strongly coupled above the electro Weakly coupled scale, and the left - chiral states have unphysical electric charges. however, the quantum properties of the model are sufficiently realistic to allow for the explicit evaluation of the gauge couplings, the properties of two extra @xmath4 symmetries, and further phenomenological implications associated with charge confinement in the strongly coupled quasi -hidden sector. by exploring the theoretical properties of this model,   we show that it is possible to obtain four - dimensionally chiral fermions from the @x math1 compactifications of m theory, and that these can be decoupled from the low energy spectrum due to charge confinement at the quasi -Hidden sector level.
dilute ferromagnetic semiconductors ( dfs s ) are materials that exhibit semiconducting charge transport behavior in conjunction with ferromagnetism induced by a small amount of magnetic impurities.   the properties of these materials have been the subject of significant fundamental research into dilute magnetism, as well as a major component of the modern applied field of " spintronics," in which both charge and spin degrees of freedom are exploited to achieve novel functionalities in devices. here   we report the results of a temperature - dependent study of the atomic and magnetic structure of @xcite, a new dfs material that exhibits a saturated magnetic moment of 1 - 2  @xmath7 per mn atom. using powder x - ray diffraction, neutron scattering, and nmr spectroscopy, we show that the zn(mn)/as layer forms a square planar network of nearest - neighbor mn atoms in the lower half of the crystallographic unit cell, with the as atom residing primarily in the as 4@xmath10 valence band. at room temperature,   this network is dominated by holes, while at low temperatures, the network is more complex and consists of a
we give a prescription for contructing type i models with only @xmath0-branes on general abelian orbifolds ( the latter have odd order or else @x Math5-brane would be present ).   we also generalize the rules of appendix  to a certain class oforbifolds with both @x math0- and @x maths5-bridges. in each case,   the type i model is constructed by compactifying the heterotic string on@xmath15 with gauge connection ( shift ) in each twisted sector ( labeled by ) from the untwisted closed string sector of the corresponding heterotic dual.the results are compared with those of ref @xcite, where we studied type i - heterotic Duality matching for the @xMath8-orbifold model of ref@xcite.
we survey for debris disks around stars in young clusters of reliable and disparate ages using the 24@xmath0 array of the _ spitzer - mips instrument.   we find a total of 1093 objects with @xmath11 < 12.0 m ( 0.12mjy ) excesses ( s / n=1093 ) around Messier 47 ( ngc 2422 ), a young galactic open cluster of several hundred stars at galactic latitude 3@x Math4 and distance around 450pc from the galactic plane. to interpret our results, we need to determine which 24@Xmath1 m sources are members of the cluster. 	 we find three possible members, p1121, p369 and p922, with largest excesses at airmass 1.8, but no evidence for the other two.
the problem of deriving relevant information on the diffusive scaling limit of tagged particle diffusion in the so - called 1-dimensional rayleigh - gas from microscopic principles has been undoubtedly at the heart of mathematically rigorous statistical physics of time dependent phenomena, at least since einstein s groundbreaking work.   we investigate the @xmath0 small mass limit of self - diffusion in this system and present numerical simulations on a new type of interacting particle system, differing from the one described above in having instead of one central particle of different mass, all particles of the same mass but the two central particles interacting via a calogero - moser - s Sutherland - type repulsive potential, with random strength parameter. using these new models, we show that the model is equivalent to the original model when the size of the tagged particle is reduced to ~1.5  nm. our simulation results reproduce very accurately the numerical value of the limiting variance of tagging particle motion in the @xcite limit, which was obtained in the late 1980-s.
the decay of the radiation field inside a cavity plays an important role in many realistic problems.   we study the optical fields propagation in realistic environment by abstracting the physical problem into a mathematical model. then using our technique on the quantum operators and the quantum states, we cleverly deduce some formulas for the propagated optical fields. these formulas are very useful to quantum optics and quantum statistics.
we propose a radical approach to the theory of defects in which the displacement field is not used as an independent variable.   instead, it is computed in those regions of medium that do not contain cores of dislocations and satisfies the equations of nonlinear elasticity theory. in this way, the geometry of defects can be considered as a continuous elastic medium with a spin structure. if the displacement vector field is a smooth function, then there are only elastic stresses corresponding to diffeomorphisms of the euclidean space. for example, if the dislocation vector field has discontinuities, then we are saying that there are defects in the elastic structure. here  , we show that the displacement fields can be computed in any region of medium where the director field has no core of dissociations. by taking into account the properties of the spin structure,   the proposed geometric approach allows considering other defects such as ferromagnets, liquid crystals, spin glasses, and spin glasses.
the centers of galaxy clusters are the densest regions of galaxy populations in the universe.   they are the places where the most frequent interactions between galaxies are expected to have taken place during the cluster formation epoch ( and maybe also in the present ). here   we report the observations of two galaxy clusters, the hydra  i and the centaurus clusters, which are located at a distance of about 45 mpc from each other near the vlt ( eso, paranal ). both galaxy clusters show a very rich globular cluster system ( gc ) around the central galaxy, an extended stellar halo around the center, and an abundant population of early - type dwarf galaxies clustered towards the center.. these findings are the result of a common scenario in which galaxy disruption played a major role in galaxy formation.
the 1720 mhz transition of oh maser emission from the interior of supernova remnants ( snr s ) with adjacent molecular clouds is an effective indicator of shock waves interacting with molecular clouds.   we propose that it is the weak x - ray flux from the snr interior that is ultimately responsible for the dissociation of  in the shocked molecular gas. using zeeman measurements of the magnetic field strength in the postshock gas, we show that the masers are formed by the endothermic reaction between the shock front and the hot, ionised gas immediately behind the shock. when the shock velocity exceeds 10 @xmath2, the gas is rapidly converted to  by a non - dissociative reaction involving the formation of oh as an intermediate in the incorporation of oxygen into water at a temperature of about 400 k. this process is not observed in the unshocked gas, but is likely to occur if the shock wave is a c - type shock, which is more efficient at converting the atomic and diatomic oxygen in the gas to  if the pressure within the remnant is high enough. on the other hand,   the present study shows that the heating of the gas in the galactic center nonther
the solar mass of cu cancri ( = gj2069a, hip41824 ) is less than @xmath7@xmath2 in the hertzsprung - russell diagram.   it is a nearby ( d=12.8pc ) 11.9-mag spectroscopic binary system with m3.5ve components and its absolute parameters have been determined by combining the photometric elements with the existing spectroscopy solutions. here   we study the light curve of cu cnc with the 0.7-m swiss telescope at the european southern observatory using the x - ray absorption spectrometer at the scandinavian university of california at los angeles. to date, only about a dozen of eclipsing red - dwarf binaries in detached systems have been detected and studied in details because of the low probability of finding them and their very low intrinsic brightness.    the results of this study show that cu cdcri is a near - neighbor of yy gem with an orbital period of 2.771468 days and a fainter visual companion at an angular distance of @x Math8. 	 the two components in
the problem of glass transition has been widely discussed in the literature, and has been considered as one of the deepest and most interesting challenges in physics.   it is widely perceived that a glass transition theory should provide a consistent explanation of several universal properties of liquids which set in on lowering the temperature, including the physical origin of the vogel - fulcher - tammann ( vft ) law, slow non - exponential relaxation and dynamic crossovers. however, there is no agreement as to what physical parameter governs glass transition. here  , we suggest that a property relevant to glass transition is elasticity because a glass differs from a liquid only by its ability to support static shear stress.we analyze elastic waves originating from atomic jumps in a liquid, and find that their effect is to create a dynamic compressive stress which slows down relaxation of other events. for example, the range of propagation of these waves increases with liquid relaxation time, and this increase gives the vft law. in the proposed theory, we also discuss the origin of two dynamic crossoververs in a Liquid, the absence of divergence of @xmath1 at@xmath4, the effect of volume on @x Math1 and the origin
graphene is considered as a prospective material for the electronics " beyond silicon ".   chemical functionalization of graphene is one of the most efficient ways to manipulate its physical properties. here   we study the effect of the ripples on chemical activity of graphene, using hydrogenation as an example, which will allow us to formulate specific recommendations how to produce graphene with a desirable type of functionalization manipulating by inhomogeneities of the substrate.
the generation of highly entangled states is a prerequisite for quantum computation and quantum communication.   we show how bell and @xmath1 states may be created in spin chains with defects, where the anisotropy of the system can be used as an extra tool toward the creation of entanglement. here  , we focus on a spin chain described by the@xmath0 model, where two different kinds of interaction are identified : the ising part, proportional to the anISotropy coupling, and the xy part, which can be use to create entanglements between two or more qubits.    we discuss how defects can also be used to create bell state when the system contains just one excited qubit. once the desired state is generated, we outline a way to preserve it with high fidelity for a long time, which requires quickly detuning the defects involved in the process.
the ability to transduce free energy into systematic movement is the defining characteristic of active matter, and my interest is in the unique mechanical properties that arise as a consequence of such active processes @xcite.   this review focuses on the collective behaviour of systems with a large number of constituents, and will thus use the ideas of condensed matter and statistical physics.the aim of this review is to complement and update the perspectives of earlier reviews@xcite and to present the achievements and limitations of this rapidly advancing subfield.
determining the strength of the solar magnetic field is important in determining the energy budget available for chromospheric heating.   the hanle and zeeman effects are commonly used to constrain the magnetic field, but their interpretation requires assumptions about the probability distribution function ( pdf ) of the turbulent magnetic field. in this work  , we ask the question " how can the turbulent fractal geometry of the magnetic fields in the solar photosphere be accounted for in interpretations of zeeman - based observations?   we attempt to derive the spectral / fractal properties from high resolution ( @xmath13 ) zeeman observations with the _ hinode _ spectro - polarimeter ( sp ) @xcite and highresolution ( down to ~14km@xmath15 ), turbulent dynamo simulations ( up to magnetic reynolds numbers, @x math16 ) with the ` muram ` code @xcitesite. using these data, we demonstrate that the peaked pdfs from stokes   @x Math1 measurements and the monotonic pdfs typically reported from numerical simulations are, in fact, compatible.. second, we extrapolate the results obtained with observations and simulations ( based on their
the continuum spectral energy distributions ( seds ) of quasars and active galactic nuclei have been studied extensively as a means of understanding these energetic objects.   the ionizing continuum of the quasar spectrum has been inferred based upon the strengths of observed emission lines, such as @xmath21640, and others. in this paper  , we show that this sed is unlikely to account for the observed equivalent width of about 54.4  ev photons in the broad emission line clouds of mrk  335 or in the composite quasar spectra. because of the paucity of ionizing photons, we find that if the observed seds have been inferred correctly, _ the broad emissions clouds must see a different, harder continuum than we observe. we present the calculations in@xmath10  2.
the radial distributions of oxygen and nitrogen abundances across the disks of 130 galaxies have been compared using the strong - line method.   the results show that the distribution of oxygen abundances in the disk of the galaxies is more variable than that in the hii regions of the same galaxies. at 12+log(o / h ) @xmath4 8.3,   secondary nitrogen becomes dominant and the nitrogen abundance increases at a faster rate than the oxygen abundance ( e.g., ~1.5 times faster than oxygen abundance ). however, the change in nitrogen abundance with galactocentric distance is much larger than that of oxygen abundance. to determine the origin of this difference, we used a set of photoionization models to construct a model - based calibration of the spectra of 130 spiral and irregular galaxies from the x - ray absorption spectrum of the southern pole of the cosmic microwave background. by using the calibration, we found that the relative contributions of the two types of isotope gradients in the radial distributions for oxygen and nitric oxide abundances are not only different but also differ significantly. as a consequence, the radial distribution of the nitrogen abundance in the galactic disks is more uniform than
we present some new conditions sufficient for convergence of fejr monotone sequences.   we also provide applications to the study of nonexpansive mappings. in particular, we consider the case of a set of nonempty closed convex subsets of @xmath2 and assume that each weak cluster point in a sequence @x Math4 is not further from any point in @x math2 than its predecessor. using  as a model, we show that these conditions are sufficient for converging fejrs with respect to a nonemptyclosed convex subset @x maths2 of @Xmath3. we also show that the same condition is sufficient for combining two different sets of weak cluster points of a sequence@xmath4 with a single strong cluster point of a subspace @xMath2 if and only if all weak cluster parts of the sequence lie in both subspaces.
the photo- and electroproduction of the strangeness electromagnetic production from the proton through the _ s-channel nucleonic resonances of spin 3/2 is investigated.   the effects of the off - shell parameters are introduced in the interaction lagrangians, and the dependence on these parameters of the non - pole part of the interactions is studied. for the photo - pion photoproduction process,   a kaon ( @xmath10 ) and a hyperon (@xmath13 ) are used to derive the general expressions valid for the processes with a kinematic value of ~1.5  kcal / mol and an energy of ~2.5 gev, respectively. by applying the same general expressions to the electro - and photo - production processes, the results are compared with the results of the recent saclay - lyon ( sl ) study   @xcite, which was based upon an effective hadronic lagrangian in the lowest ( tree ) approximation.
we study the local density of states ( ldos ) in a quarter - filled one - dimensional mott insulator in the presence of a strong impurity potential.   the spatial fourier transform of the tunneling conductance is analyzed by means of the single - particle green function, which is derived from the field theoretical description of the q - quasiparticle excitations of the mott Insulator.    we find two dispersing features which follow the dispersion relations and are observed in the fourier transforms of the ldos in the absence of an impurity.. these features can be interpreted as arising from an antisoliton or a spinon -antisoliton pair propagating between the position of the stm tip and the impurity ; however, they also appear in the case of a charge - density wave state with a gap in the charge sector.
the ground states of spin-3 bose - einstein condensates ( becs ) are calculated under the assumption of conserved magnetization.   the effects of the dipole - dipole interaction, which is known to enable conversion of spin angular momentum into orbital angular momentum, are studied in the special case of a @xmath0cr condensate and the possible experiments are discussed.
the @xmath0he@xmath6 system is investigated within a mathematically rigorous method of solving a three - body problem in the boundary - condition model developed in   @xcite.   the repulsive component of the he  he interaction at short distances between atons is approximated by a hard core and the binding energies of the ground and excited states of the helium trimer are calculated. for the ground - state energy of the dimer, the solution is based on a direct solving of the two - dimensional faddeev differential equations in configuration space while for the excited states the results are based on an approximation of the three - atomic hamiltonian using the laplacian operator instead of the sum of this operator and the huge repulsive components of the interatomic he   he - potentials. as a result of the calculations,   both the ground- and excited - state energies of all the helium atoms in the trimer have been found to be accurately determined. moreover, the binding energy of each atom on a helium dimer has been determined.
we propose a generalization of detailed balance for the description of non - gaussian jump - type processes, with a focus on the existence of asymptotic ( large time limit ) invariant probability density functions ( pdfs ) of the manifest boltzmann form.   this is achieved by turning over from the master equation to the affiliated semigroup dynamics, which is a suitable functional form of the semigroup potential ( which we consider to be a continuous function ) that allows for a unique asymaptotic invariant state. in particular, we show that the inhomogeneity of the physical environment in which jumps take place can be quantified by mapping the master differential equation to a fractional version of the generalized diffusion equation. under the assumption that the target pdfs are selected from so - called cauchy - type pdfs, we find that the lvy @xmath1 - targeting is consistent with the results of the kinetic theory derivations of the langevin model for confined lvy flights, and that the thermalization of the resulting master equation is driven by a locally defined scenario of an energy exchange with the thermostat.
we show that a non - equilibrium steady - state is reached in the bose - hubbard model of quantum criticality.   we show that the out - of - equilibrium distribution function is far from thermal, and that an expansion about a thermal distribution at some effective temperature is not sufficient to capture the out-of - equilibrium state. using a boltzmann - langevin approach   it is shown that a distribution that is highly elongated along the field direction is a good variational solution of the Boltzmann equation for the non - equilibrim conductivity and current noise.
multiplicatively interacting stochastic processes(misps ) are considered one of the probable candidates for explaining power - law tails observed widely in natural phenomena, such as velocity distributions of inelastically colliding particles and wealth distributions in economics.   there exist two parameters characterizing the processes : a growth rate of systems and a power -law exponent which are able to be calculated analytically. here  , we introduce a method of fourier transform which is usually used for calculating the growth rate @xmath1 and the exponent @x Math2 of granular gas systems@xcite and other misps. in this method, we find that both parameters vary continuously depending on microscopic interaction parameters in a certain region.the principle of minimum growth rate is also discussed.
astrodynamical space test of relativity using optical devices ( astrod ) aims at testing relativistic gravity, measuring the solar - system parameters with high precision and detecting gravitational waves from massive black holes and galactic binary stars.   the concept of astrod is to put two spacecraft in separate solar orbits and carry out laser interferometic ranging with earth reference stations ( e.g. a spacecraft at the earth - sun l1/l2 points ). in this paper  , we carry out analyses, mainly based on existing literature on acceleration disturbances for other gravitational missions ( lisa@xcite and the lisa pathfinder @xcite ), to give a preliminary overview of the acceleration disturbance to the astrod i proof mass. based on the analyses, we infer some of the requirements for the designs of the payload and spacecraft. also, we compare parameter values we have assumed in the analyses with those for lisa to confirm the feasibility of these requirements.
we study the coherent transmission of slow photons in a coupled resonator optical waveguide ( crow ) with homogeneous couplings, each cavity is doped to a two - level artificial atom.   we calculate the two - time retarded green function for photons in the weak - coupling case and its poles predict the exact dispersion relation, according to which the group velocity can be coherently controlled by the collective excitation of the doping atoms. using this method, we show that the coherent output of slow photon transmission in the crow interacting with doping atoms can be controlled by controlling the bandwidth and group velocity of the doped atoms through some new mechanisms.
spin - glass physics is a fascinating subject of condensed matter physics.   it is characterized by an ordered magnetic state with permanent magnetic moments in the microscopic scale, but randomly oriented producing a vanishing net macroscopic magnetization. while the concept of spin itself is purely quantum, it is often maintained that quantum fluctuations are not important for spin - Glass physics @xcite. in this work   we consider the su(2 ) heisenberg model for a system of @xmath0 spins with random infinite - range exchange random interactions. using the method of numerical exact diagonalization of finite size clusters to investigate models of quantum random magnets at@xmath4, we obtain an appealing physical picture of the low energy excitations of the Spin - Glass state that would have not emerged from classical model numerical calculations.
the eigenvalue relaxation is a new method for solving penalized binary least squares estimation problems of the form @xmath3 where the vector @x math4 is the observed data, the matrix @x maths5 represents the " filter ", the vector@xmath6 is the signal, or parameter vector, and the term @x Math7 is a penalization term.   the main advantage of the eigen value relaxation over the semi - definite programming relaxation is that it can be solved much faster than the semi definite programming ( sdp ) based relaxation. in the present paper  , we survey what is known about the relationship between lagrangian duality and the eigenshape relaxation for this problem. as a by product, a new geometric interpretation of the randomized algorithm is proposed.
the monogamy of entanglement is a key property of quantum mechanics and plays crucial role in various applications in quantum information processing.   we have recently found an interesting monogamy equation for @xmath1-dimensional ( or multiple qubits ) quantum pure states which relates the bipartite concurrence, concurrence of assistance ( coa ) and ghz type tripartite entanglements. in this paper  , we first present a new monogamy inequality for@xmath2-dimensional q1-doped systems of qubits ; then we reveal that the difference between concurrence and negativity can characterize the w type entangler.. the distinct advantage is that the " residual quantity " deduced from the equation can characterize both the ghz and w types of entanities as a whole. furthermore, it is invariant under local unitary transformations and does not increase under the local operations performed on the @x Math2- dimensional subsystem, hence it is an entangling semi - monotone.
the polarisation measurement of the beam polarisation of the @xmath0-beams at the interleukin-5 ( ilc ) detector at the synchrotron centre in chennai, china, is one of the most ambitious projects in the field of quantum chemistry.   the polarisation measurements will be carried out via compton polarimeters, where cherenkov counters detect the backscattered compton electrons. to achieve a precision of 0.25%  , it is necessary to measure the polarisations of the laser light scattered off the@x Math0- Beams with about @x math1 interactions per bunch.    the linearity of all detector components is extremely important, since all non - linear effects ( photodetectors, electronics, etc. ) need to be measured precisely and corrected for if necessary. here   we present a test stand based on camac electronics that can be used to develop different techniques for on- and off - line linearity measurements of various electronics components and different photomultipliers.
spin transfer torque - based random access memory ( stt - ram ) devices have the potential to dominate the embedded and standalone memory world in the near future.   however, they must meet the following requirements to compete with existing embedded technology : ( i ) a tunneling magnetoresistance ( tmr ) of > 150% for low - power read ; ( ii ) thermal stability ( @xmath2 ) greater than 60 to achieve high static reliability ; ( iii ) a scalable spin transfer torques switching current (@xmath3 1.5 x @x Math4 a/@x maths5 ) ; ( iv ) a very low write error rate ( wer ) ( ~0.6 ns ) with a fast device write time ( ~10ns ) ; and ( v ) an overall low energy write ( ~71pj ), which corresponds to a low switching voltage ( ~1.5 j / cm2 ). achieving such a diverse set of targets will require meticulous design and material engineering. in this paper  , we introduce a model that can be used to calculate the current and energy consumed during a write operation with an acceptable wer for a given pulse width, @x math11, in
classification of galaxies is a powerful tool for studying galaxy evolution, but it is also a sure formula for endless bickering among specialists.   hubble s ( 1926 ) simple scheme for classifying galaxy morphology has proved remarkably versatile and robust, but the complexity of galaxy morphologies means that any classification is likely to be based on a rather complex mixture of properties rather than a single defining feature. in this review,   we discuss the recent advances in our understanding of galaxy evolution using data from the _ hubble space telescope _ ( hst ), which have enabled us to classify galaxies at high redshift using a variety of techniques including visual classification, surface - brightness analysis, and automated classification. with the advent of high - resolution imaging of galaxies at redshift of @xmath2, we show that the general framework of the early - to - late sequence established by hubble is now well supported by evidence for even more recent evolution in the form of an increase in the size of the central bulge and the smoothness and pitch angle of the spiral arms, as well as the presence of a strong non - axisymmetric distortion in the central region of the galaxy, and the existence of barred and un
the glassy behavior of disordered systems with localized electrons at low temperatures has been observed experimentally in many different types of materials, like doped semiconductors,@xcite granular metals and two - dimensional systems.   it is known that the conductivity relaxes logarithmically as a function of time after an initial quench or perturbation. here   we show that this relaxation is due to the relaxation of the effective electron temperature during a quench from an initial random state. using dynamical monte carlo simulations of the standard lattice model of the electron glass, we find that the temperature of the system gradually relaxes over almost three decades in time and that the system demonstrates simple aging behavior in a stress aging protocol similar to what is seen in the experiments.
a scalar field with super - negative pressure called a phantom field can be obtained by switching the sign of the kinetic energy in the lagrangian for a standard scalar fields.   the main goal of this paper is to model the phantom fields in terms of scalar Fields with a potential rather than in termsof the barotropic equation of state. for the latter case   it is shown that the dynamics of the flat friedmann - robertson - walker ( frw ) model can be reduced to the form of a two - dimensional dynamical system on a double sheeted phase space using the framework of phase space and the theory of late - time attractors.
diquark - quark models of baryon @xcite are used to reproduce the mass spectra, the decay rates, the magnetic moments, the ratio of the axial - vector coupling to the vector coupling, the charge radius, and the processes of deep - inelastic scattering.   however, a functional method using the bethe - salpeter ( bs ) equation with the dyson - schwinger ( ds ) equations has been considered to have no diquark bound - state solutions. in this paper, we investigate the differences among previous studies which make these solutions absent, and propose another approximation scheme for the bs equation in which they exist. to this end  , we employ the same quantum chromodynamics model as refs.@xcite, i.e., the munczek - nemirovsky model. by means of this model, we find that a certain crossed ladder diagram gives a large repulsive contribution in the diquarks bs eq. due to its enhanced color factor @xmath1, and then we perform a resummation of these diagrams adopting large-@x Math1 counting as a criteria for the truncation @xcites,
the organic magnetoresistance ( omr ) is a robust effect of the spin interactions in amorphous organic semiconductors ( osc ), which is observed under weak magnetic field and room temperature.   the origin of the omr is recognized to be the spin interaction in osc, such as the hyperfine interaction@xcite and the spin - orbit coupling @xcite. however, the quantum correlation between the carrier s spin and the local environment of spin ( les ) formed by the spin interactions is not well understood. in this paper  , we show that the spin quantum correlation can be used to explain the incoherent hopping of charge carriers among different localized electronic states assisted by the lattice vibrations in an organic spintronics device using the nanoseconds time scale theory. for the first time, we find that the spins of the charge carriers are positively correlated with the local environments of spin in the presence of the coherent hopping. on the basis of these results,   we propose a new model for the quantum coherence of the atomistic approach to the omrs.
the standard way to construct a mass model for a spiral galaxy is to make composite disc / halo models assuming a " maximum disc" solution, or to adopt a " best fit ".   such models are based on the assumption of a constant mass - to - light ratio of the visible components, bulge and disc, and an additional dark halo component added when necessary. in this review  , i will comment on the recent work on rotation curves and mass models of spiral galaxies, and in particular address part of the question whether the maximum disc hypothesis is justified.
the ferromagnetic ising model with antiferromagnetic next - nearest neighbor couplings on square lattice@xcite is studied numerically.   the critical properties of the model are verified by transfer matrix calculations and monte carlo simulations. in particular, the fractal structure of spin clusters is studied for the first time.
the radial abundance distributions of heavy elements in the cold gas component of spiral galaxies show a complex nonlinear behaviour.   we present the first numerical hydrodynamic simulations that self - consistently explain the formation of a plateau in the heavy element abundance distribution in the vicinity of corotation by a selective action of star formation and the development of cyclones and anticyclones in the gas flow around corotation. using the thin - disk approximation, we study the influence of the radial abundance distribution of light and heavy elements on the radial migrations of stars, cold gas clouds, and dust in the surrounding region of the corotation resonance in a simulation of a model galaxy with a warm gas component and a non - axisymmetric stellar component.. the results show that the observed observations of the existence of cyclone and anticoncentre - forming anticyclone clusters in the hot gas component near corotation are consistent with the hydrodynamical explanation for the observed observation of a nonlinear radial distribution of heavy metals in this region.
we present evidence for a non - uniform spatial distribution of x - ray sources in ngc  4697, an elliptical galaxy without any indication for merging activity from optical data, and we compare these results with similar observations of other early - type galaxies.   we find that the number of discrete x - rays in the galaxy is not uniform, but rather follows the distribution of the optical star - light. using the ciao v2.2 data analysis suite, we find a second example of a non-uniform source spatial distribution in ngc  4261, a nearby e2 type galaxy, which has been observed for 35  ks with the acis - s3 ccd on - board the x -ray observatory.
abstractthe accretion of a remnant torus around a neutron star - black hole ( ns - bh ) formed promptly after a binary neutron star ( bns ) merger is the leading scenario to explain the formation of a short gamma - ray burst ( sgrb ).   however, the recent discovery of long - lasting x - ray afterglows in the vast majority of sgrbs indicates that the merger leads to the creation of a long - lived, rapidly rotating ns ( a millisecond magnetar ; henceforth referred to as the " magnetar model " ; e.g., @xcite ). here  , we investigate the magnetic field properties of the bns merger remnant by fully general - relativistic magnetohydrodynamic simulations and show that it is characterized by a very dense, highly magnetized wind that carries sufficient poynting flux to explain typical luminosities of early x - rays observed by the _ swift _   satellite @xaite. using models of hypermassive neutron stars with different initial magnetic field geometries constructed with the rns code whiskymhd@xcite combined with the publicly available einstein toolkit and its spacetime evolution code mcl
in the gravitational collapse or pulsation of neutral stellar cores at densities comparable to the nuclear density, complex dynamical processes are expected to take place.   these involve both macroscopic processes such as gravitational and hydrodynamical processes, as well as microscopic processes due to the strong and electroweak interactions. in this article  , we present our studies of the space - time evolution of electric processes in the dynamical perturbations of neutral star - like cores caused by either the gravitationally collapsing or pulsating of the baryon core. for each process,   the electric field ( charge separation ) is assumed to evolve in space and time, and some electromagnetic processes can result if their reaction rates are rapid enough, for example, the electron - positron pair - production process of sauter - heisenberg - euler - schwinger for electric fields @xmath0. if this indeed occurs, gravitational and pulsating energies of neutral stars are converted into the observable energy of electrons via the space- and time - evolution of electrical fields.
the values of the cosmological parameters are now determined by various methods.   the strongest lower limits for the globular cluster age come from studies of the stellar populations of globular clusters ( gcs ), and the best estimates of the ages of the oldest gcs from main sequence turnoff magnitudes were @xmath18 gyr ( @xcite ). in spring of 1997  , analyses of data from the hipparcos astrometric satellite indicated that the distances to gcs assumed in obtaining the ages just discussed were systematically underestimated : a 0.25 magnitude error in the distance modulus translates to a 22% error in their derived cluster age.    the solar neutrino problem reminds us that we are not really sure how even our nearest star operates ; and the sun plays an important role in calibrating stellar evolution, since it is the only star whose age we know independently ( from radioactive dating of early solar system material).in this review,   i discuss the current state of knowledge about the cosmsological parameters.
we establish two theorems for the reduction of the grbner base of the syzygy ideal of quaternionic polynomials in the field of rational numbers.   the first theorem provides very simple generators of @xmath3, called the _ syzyy ideal _ of quatenionic poynomials. using the classical theory and algorithm on non - commutative gr bner bases, one can compute the Grbner bases of the Syzygy Ideal of quannomials with coefficients in the rational numbers field for a fixed number @x Math4 of quaterionic variables, and for every degree @x math6, the number of degree-@xmath6 polynomial in the computed grbneur base is finite. after investigating the elements in the grBner bases for small values of arbitrary @x maths4 and @xMath6, we come up with some observations on the general form of thegrbnerbase for arbitrary @Xmath4 and from the structure of the normal forms of quennomials relative to the grfner base.. the results are not only foundations for symbolic manipulations of quelfth - order quaternion
photoproduction of pseudoscalar mesons off complex nuclei at few gev energies is now possible via the primakoff effect.   the precision measurement of the radiative decay widths of @xmath2 mesons from experimental data has recently been completed at jefferson lab   @xcite. in the present work   we consider the incoherent photoproductions of @Xmath2 and the other@xmath3 and @x Math4 mesons, + a ps+a^ ( ps = ^0,, ^ ), by means of glauber multiple scattering theory. to obtain the correct expressions for the process,   corrections to the cross section of the irradiated quarks are taken into account. as a result  , the obtained expressions can be applied to the coherent photop reproduction of the other @x maths mesons.
beryllium ( be ) is a stable isotope of the single stable element, @xmath1be, which is a product of cosmic - ray spallation of heavy nuclei in the interstellar medium.   it has been used as a cosmochronometer for the early stages of the galaxy by means of its abundances in metal - poor stars and its use as a discriminator of the different stellar populations in the galaxy. here   we review the results of a recent study that extends the investigation of be as an early galaxy cosmophotometer and shows that it can be used to discriminate between different star populations.
a decade ago, solar models matched the sun remarkably well.   sound speed profiles in models differed from the sun s actual sound speed by less than half a percent. then @xcite reanalyzed the solar optical spectrum using improved atomic physics and a 3d hydrodynamical model of the atmosphere ( instead of a 1d hydrostatic model ). their results indicate that the abundances of the heavy elements should be lower by a substantial amount. since the mismatch between seismology and the new abundances remains a problem, a seismic determination of theheavy element abundances in the solar convection zone is necessary. here   we discuss the techniques for a seismic measurement of heavy elements.
dark matter caustics are regions of infinite density in the limit where the dark matter particles have zero velocity dispersion.   the leading dark matter candidates, namely axions and weakly interacting massive particles(wimps ), have very small primordial velocity dispersions ( @xmath0 cm / s for a 100 gev wimp,@xmath2ev axion for a 10 x 10 axion ) and may be expected to form Caustics with large density enhancements. if these wimps are made up of axions, they can annihilate producing gamma rays which can be detected by means of glast experiments. here  , we discuss dark matter annihilation in caustic spheres and rings and present simulated gamma ray sky maps.
inflation is thought to occur near the planck scale.   the origin of the cosmic microwave background ( cmb ) fluctuations is found in the quantum fluctuations of the scalar field and it is expected that these inflationary parameters restrict the models of particle physics. in this paper   we consider that the inflaton field is a real scalar fields with a quartic self - interaction and a non - minimal scalar - curvature interaction at high - energy scale and study a possible model consistent with the cmb fluctuations at the two loop level.    the inflationary parameter space is extended up to the next to leading log level with respect to the scalarsquare quartic coupling, @xmath3, and the effect of the quantum correction is studied. for the first time we consider a massless scalar Field with a non-minimal scalar curvature coupling,@xmath2, and adopt a simple chaotic inflation scenario near thePlanck scale where the reduced planck mass is set as @x Math2.. the inflationaries are numerically evaluated and shown to be compatible with the observed data.
we present a generalization of the thermal discrete dipole approximation ( tdda ) method to describe the near - field radiative heat transfer ( nfrht ) between two magneto - optical ( mo ) objects of arbitrary shape by discretizing them in terms of point dipoles.   we show that the proposed method is valid for optically anisotropic systems that can be described by an arbitrary electric permittivity tensor ( with @xmath1 ) and it is also valid for the thermal emission of a finite object ( both mo and non - mo ) under a static external magnetic field, which can be controlled by changing the magnitude and the direction of the field. as a proof of principle, we demonstrate that the results obtained from the experiments are in good agreement with the theoretical description of the radiation exchange between two doped semiconductors made of doped nanocrystalline materials.
we present a novel adaptive neural network approach to the classification of ultra - dense array configurations generated by the magnetization reversal within the xy superlattice model of magnetic nanostructures.   the proposed method is based on the use of adaptive neural networks which are nonlinear models suitable to reduce, classify or interpolate data structures representing the complex patterns @xcite. in the presented paper   we show that the performance of the proposed algorithm is compared with the results obtained from the monte carlo and micromagnetic spin lattice dynamical simulations of@xcite using self - organized neural network training. as a result   it is found that the learning time of the neural network is faster than that of the experimentally observed experiments.    the classification is applied to configuration generated by reversals generated by dipole shape anisotropy associated with demagnetworking of thin film sample @xcites.
the contemporary ( riemannian ) geometry is overdetermined and hence it is inconsistent.   although the character of inconsistency is known long ago, the mathematical community as a whole does not want to acknowledge these inconsistencies and bypasses them.the content of the crisis lies in the fact that the mistakes in geometry ( more exact in the construction of generalized geometries ) are not acknowledged and not corrected, but not in the existence of mistakes in themselves. as a result the geometry is developed in the direction, which leads in the blind alley.the presented paper is devoted to this question.
the production efficiency of the lyman continuum ( lyc ) photons responsible for the cosmic reionisation of hydrogen is a key goal of modern extragalactic astrophysics.   the production efficiency can be predicted using a stellar population synthesis ( sps ) model for a given star formation and metal enrichment history and initial mass function. in this study   we couple six sps models with the bluetides hydrodynamical simulation to predict the lyc photon production efficiency. by including observations of the uv continuum slope at @xmath8, we show that the prediction production efficiency increases as a function of stellar mass (   ), redshift (  = 0.037 ), and choice of sps model (  < 0.001 ).    the results are consistent with the observed emission of h@xmath12 in a sample of spectroscopically confirmed lensed lyman - break galaxies at @Xmath13.
the polarization of the cosmic microwave background ( cmb ) anisotropies provides us with a wealth of additional cosmological information which we have only just begun to probe.   however, the polarization signal is dominated by foregrounds, and it is not yet clear how well the problem of foreground contamination can be solved. in this paper  , we introduce and analyse another general method of testing for residual foreground contamination in cmb polarization maps, the @xmath0 statistic of @xcite. as both the synchrotron and non - spherical dust foreground components have strong overall directionality on large scales, we argue that this statistic is well suited to the detection of foreground contaminant contamination, as both these components are strongly correlated with each other over the whole spectrum of the cmb temperature anisotropy power spectrum. using the _ wmap _   3-yr polarization data from the _ planck satellite, we demonstrate its usefulness for real data analysis.
@xcite multiwalled carbon nanotubes ( mwcnts ) have been used as antennas.   the performance of the cnts as antennas is investigated by means of a theoretical model of the effective boundary conditions for the electromagnetic field on the surface of the multilayered cnt, which is based on the analysis of the intershell interaction leading to intershell electron tunneling or hopping. in the presence of localized defects,   it is possible to increase the frequency of intershell tunneling and hopping by about two orders of magnitude, but not by more than one order of magnitude. at the same time, the radiation characteristics of the antenna are affected by the intrinsic symmetries of the shells, which dictates selection rules for the elements of the tunneling matrix, as determined by the conservation laws for energy and momentum.
the coherent destruction of tunneling ( cdt ) phenomenon is studied for a molecular wire coupled to two leads acting as electron source and drain.   the current through the wire is measured using a time - dependent laser field which is coupled to the wire and/or the leads via a wire - lead coupling. in order to study the effect of the laser field on the electron dynamics in the wire   it is necessary to average over several of the high - frequency oscillations of the carrier frequency. by averaging over these oscillations   we show that the cdt phenomenon does not only survive for shorter laser pulses but also for longer pulses.
the rate of galaxy mergers in clusters of galaxies is determined by the cross sections and reaction rates of encounters between equal - mass galaxy models of various types.   the results are compared with those of previous simulations of galaxy encounters, and show that the rate of merger is significantly enhanced when the encounter takes place at relatively low speed. for a given cluster of galaxies, with a given population of specified galaxy halos, the net merger rate can be determined by an integration of the usual @xmath3 factor ( density cross section cross section velocity ) over a maxwellian or lowered maxwellians velocity distribution.. the results can be readily applied to study the evolution of galaxy clusters, if we use our models to represent dark matter halos around galaxies in the limit that these halos can be considered to be spherical.
we define a mapping of dynamical systems onto a network.   this way, the network properties can be used to display new features for the characterization of the system s trajectory. in particular, we explore those regimes at the onset of chaos that proceed through a bifurcation cascade as well as those close to an intermittency transition and also the full development of chaos. using the measures that have been recently developed to characterize complex networks, we find novel geometric and topological properties of the phase space through the analysis of the quadratic map of the dynamical system described by @xmath2 where the system is defined on the time domain and the network nodes correspond to coarse - grained regions ( cells ) of the phases visited by the trajectories. here, we apply these measures to the investigation of the dynamics of undirected networks, which are defined by the number of nodes and links per node and the average number of pairs of nodes per node. with respect to the latter, we show that the average clustering coefficient, the mean minimal distance among the nodes, the diameter, the probability distribution of nodes with links and the assortativity degree of each node in the network are all significantly different..
we use molecular dynamics simulations to study the dynamics of a binary mixture of charged particles with a size  ratio of 1:5.   the system exhibits a phase transition from a fluid to a mixture of crystalline large particles and fluid  like small particles. in the temperature regime between the freezing transition and the final crystallization into a sublattice, the movement of the small particles can be characterized by a hopping motion in an external periodic potential ( created by the large particles ). at a given wavenumber, the particle   particle interactions are modelled by an effective screened coulomb potential, where the screening parameter is the distance between two particles at contact. for the excluded volume of the particles,   a shifted lennard  jones potential is used to model the exclusion of the bulk volume. as a function of the number of particles in the suspension, the effective packing fraction of the mobile small particles is calculated.    the results show that the mobility of the smaller particles is governed by structural correlations among the larger particles, which are associated with a complex distribution of single particle potential energies.
this year marks the @xmath0 anniversary of two seminal papers by slonczewski and berger on the spin transfer torque ( stt ) phenomenon, which refers to the transfer of angular momentum from a spin - polarized charge current, or a pure spin current, to a local magnetization.   the two most important consequences of stt are  i  the possibility of programming a magnetic memory, such as magnetoresistive random - access memory ( mram ), using a small direct current through the bit, rather than larger currents through adjacent programming lines, and  ii  the possibilities of creating nanoscopic and ultratunable microwave signal generators without the need for any semiconductor materials. in this paper  , we review the fundamentals and state of the art of so - calledspin transfer torque and spin hall effect nano - oscillators ( stnos and shnos ).
electromagnetic form factors ( emffs ) are the most fundamental observables that reveal the charge and magnetisation structures of the nucleon.   a series of recent measurements of the proton magnetic form factors, obtained by measuring the transverse and longitudinal recoil proton polarisations from unpolarised electron - proton scattering at higher @xmath5, have renewed the understanding of the internal structure of the nucleus and posed fundamental questions about its nonperturbative nature. in this paper  , we investigate the flavour structure of these form factors within the framework of the self - consistent su(2 ) and su(3 ) chiral quark - soliton models ( @x Math0qsms ). using the experimental data for the up- and down - quark form factors as input, we find that the effect of two - photon exchange on the form factorisation scheme is well reproduced within the@xmath0qsm, so that the results of the experiments are in good agreement with the predictions of the @x math0 qsm.. however, the flavour - decomposed form factors behave in a different way from the prosurvival ones, which show a complicated behavior for lower
the equations governing the dynamics of non - magnetized stellar plasma are well known, but a fundamental understanding of fully developed turbulent flow remains elusive. in order to develop a more realistic physical description of stellar turbulence, which is of central importance to modeling stellar pulsation, a better understanding of these non - linear terms is needed.   we present a few select models from a new suite of turbulent stellar convection simulations designed to this end and briefly discuss the origin of the kinetic energy flux and its relationship to the grid - scale dissipation and the large scale topology of the flow.
a two - dimensional ( 2d ) semi - analytical model for calculating acoustic response to a line - focused laser pulse in an optically absorptive isotropic cylinder is proposed.   the thermoelastic regime of generation is assumed and a typical case of materials with negligible thermal conductivity is treated, where the laser input penetrates into the target and creates a volume distribution of thermal sources inside the cylinder through the optical absorption. performing two inverse fourier transforms yields the sought waveforms of acoustic response in the time - space domain. by comparing the results obtained for the two different source settings,   it is observed that the waveforms, computed for a buried source tending to the surface, agree very well with those following for scruby s surface - source model, whereas the waves computed for distributed sources have essentially different shapes comparatively to the prediction following for the surface source.
heavy quarkonia have a rich spectroscopy with many narrow states lying under the threshold of open flavour production.   excited states experience different decays among which there are radiative transitions to lower levels. in the relativistic description of mesons   an important role is played by properties of the confining quark - antiquark interaction, in particular its lorentz structure. at present, it is not possible to obtain the @xmath8 potential in the whole range of distances from the basic principles of quantum chromodynamics ( qcd ). as a result, the growing of the strong coupling constant with distance makes perturbation theory inapplicable at large distances ( in the infrared region ). in this region   it is necessary to account for nonperturbative effects connected with the complicated structure of the qcd vacuum.the purpose of this paper is to give a detailed analysis of mass spectra and radiative transition in charmonium, bottomonium and@xmath0 mesons with the comprehensive account of the relativation effects.    the results show that the @Xmath0 ground state is the most sensitive to relativism.  also, the decay rates of the @
thomson s theorem states that the electric charge density on a set of fixed conductors at static equilibrium is distributed on the surface of the conductors in such a way that the interior electric field is zero and the surface electric fields are normal to the surface.   we derive an analogous theorem on the magnetic field and current distribution in ideal conductors using a variational principle and discuss previous work on the problem. here, we show that the theorem is valid for type i superconductors with zero resistivity and that the energy reduction due to the interior field expulsion can be calculated explicitly.
we propose a measure of inhomogeneity analogous to the kullback - leibler divergence in information theory.   we also conjectured that the measure  (  ) is an increasing function of time for sufficiently large times. in this paper  , we explore the time evolution of the measure using specific models of an inhomogeneous universe, and examine on what condition the time - increasing nature of the measured measure holds.we employ the linear perturbation theory of a spatially flat friedmann - lematre - robertson - walker ( flrw ) universe and a spherically symmetric nonlinear solution as inhomogenous universe models, and illustrate the temporal behavior of our measure explicitly with the models. by comparing the time derivatives of the measures derived from these models with those derived from the cosmological principle, we show that the time derivative of the model is not always equal to zero, but rather it is more or less equal to 1 for sufficiently many times.    we also show that when the model includes local inhomogeneities, the dimensionality of the mean energy density increases linearly with the length of time, and that the entropy of the
the haldane model of heisenberg antiferromagnetic ( af ) spin chains with bond - alternating exchange interactions of alternating strength is a new model of quantum magnetism.   it is based on the observation that the energy gap in the excitation spectrum decreases with increasing field gap, and then re - opens at some critical value. as the alternation parameter @xmath3 deviates from zero, the energy gaps in the excited state decrease and close, and the ground state becomes a dimerized one. for axially symmetric and asymmetric models,   the transition to the dimerization state is caused by a non - vanishing af string order parameter, which is related to a breaking of a single non - local symmetry. here   we review the experimental evidence for the existence of a quantum spin liquid in the @x Math@xmath0 model, and discuss the implications of this model for the theory of strong magnetic fields.
the theory of random geometric graphs ( rgg ) enables research of complex networks via geometry.   it is attractive to imagine the nodes of a complex network embedded in space, as this can provide useful intuition about an otherwise complicated and abstract discrete structure. here   we show that scale - invariance of a random geometric graph ensemble can be achieved by demanding that the statistics of the resulting graph ensemble depend only on total size and not the spatial or temporal scale. for a scale - free rgg,   this simple constraint induces a range of emergent properties in the generated networks : a dichotomy between scales - free and poisson distribution of in- and out - degree, the existence of a randomly number of hub nodes, high clustering, and unusual percolation behaviour.
the nonlinear schrdinger ( nls ) equation is a universal model of weakly nonlinear dispersive media @xcite.   the existence and stability of solitons in the one - dimensional ( 1d ) version of the nls equation with constant coefficients is a well - established fact, which has important implications in various areas of physics. here  , we introduce a new class of dynamical problems, which also have a vast potential for physical applications, in which coefficients are periodic functions of the evolutional variable in the extended versions of the Nls equation. by means of time - periodic ( ac ) management of the confining potential in the quasi-1d bose - einstein condensate context,   it is possible to modulate the nonlinearity coefficient in the linear part of the equation so that it periodically alternates between positive and negative values. as a proof of this theory, we investigate the effects of ac management on the propagation of a light beam through a periodic concatenation of nonlinear waveguiding and antiwaveguiding segments in a fiber - optic link subjected to _ dispersion management _ ( dm ), which implies that the dispersion coefficient periodically altern
the problem of electrostatic interactions between two surfaces is one of profound importance in the theory of colloidal stability and also in the understanding of thin liquid films.   the precise qualitative behavior is still only understood within the context of mean field poisson - boltzmann type theories, and at a more sophisticated level using the hyper - netted chain approximation ( hnc ). in this paper   we propose to analyze the exactly soluble one dimensional version of the model proposed in @xcite for soap films made from sodium dodecyl sulphate ( sds ) by comparing our exact results with those of mean fields.
we present a method for the numerical calculation of solutions to general hyperbolic partial differential equations ( pdes ) over the sphere that combines several existing techniques in novel ways.   our motivating interest is the analysis of gravitational radiation in a neighbourhood of infinity via friedrich s conformal field equations @xcite, where it is convenient to regard space - time as the product of a lorentzian manifold and a euclidean @xmath1-sphere. to implement our spectral method we choose to work with spin weighted spherical harmonics ( swshs ) and the associated@xmath3 and @x Math4 operators @xcites.    we use a hybrid linear / non - linear recursion that avoids the numerical problems that both linear and non -linear recursive schemes suffer from.. the algorithm is theoretically exact if a minimum number of grid points are used.
the standard model(sm ) is a renormalizable gauge theory of strong and electroweak interactions based on the guage group @xmath3.   it gives a successful explanation for most of the phenomena governing fundamental processes, and is in excellent agreement with the experimental data to date. however, there are a number of unanswered questions which motivates us to think beyond the sm. here   we propose to investigate the production and decay of exotic top - like quermions at the large hadron collider(lhc ) using two dacay channels, namely @x Math9@xmath10 and @x maths9@Xmath11 tz.. we find that the former channel leads to a rather unique and background free signature arising from a @x math12 state.    this signature is consistent with the results of the experimentally discovered higgs boson(h ) and the z boson ( gev ), and can be explained by the existence of a sequential fourth generation vectorlike quark.
hot accretion flows such as advection dominated accretion flow ( adaf ) are of great interest because they are likely operating in low luminosity active galactic nuclei, which are the majority of galaxies at least in the nearby universe, and the hard / quiescent states of black hole x - ray binaries.   many numerical simulations have been carried out to study the structure of hot accretions by assuming radial self - similarity. however, numerical simulations show that the viscosity has nine components. in this paper  , we present two - dimensional analytical solutions for hot accrete flow without wind using the same methodology as described in shadmehri ( 2014 ). a solution with only the ( @xmath10 ) component of viscosities   is presented based on the results of three - dimensional numerical simulations where the (@xmath9 ) component dominates the other components. from the proposed solution,   it is found that the bondi accretion rate, jet production efficiency, and jet power are determined by the gas properties at the bonds between the black hole and the surrounding gas. despite the existence of wind, observations of the nuclei in the centers of cool - core clusters
in a recent study, the measurements of eclipse egress times of the eclipsing polar binary hu aquarii ( hu aqr ) were used to infer the presence of a circumbinary planet around this system.   the proposed planetary system was found to have a different orbital architecture than the one proposed by @xcite. in this work   we aim to find a more plausible orbital architecture that best describes the timing data while also being conform with orbital stability requirements. using a monte carlo, least - squared model of the light - travel time ( ltt ) effect, we carried out a stability analysis of various ltt model orbits which best describe the complete timing data set. by parameterising planet s hill radii, we imposed orbital stability constraints to our parameter survey in order to explore orbital architectures that result in stable orbits. by applying these constraints to systems that also allow the inner planet to attain an eccentric orbit  , we extend the models by@xcite to systems where the outer planet can be considered to be in an orbit with a high eccentricity and show that two - planet ltt models tend to produce orbits with higher eccentricities which are likely unstable.
we have investigated the quantum size effect ( qse ) on the dielectric function of al(111 ) films with bothaband and interband contributions in the thickness range from 1 monolayer ( ml ) to 39  mls, using first - principles density functional theory ( dft ) calculations within the random phase approximation ( rpa ) @xcite.   we found that the plasma frequency is reduced due to the transfer of electronic transition strength from theaband to interband transitions and the amount of such reduction oscillates as a function of film thickness. also, for the films thinner than 15  mm, the imaginary part of in - plane dielectrics with energy greater than 1.5  ev is decreased to be smaller than the bulk value, which may translate into less energy loss in the plasmonic devices made of thin films.
the trade - off between sharpness and biasedness of measurement is studied for multi - outcome spin measurement in the context of quantum mechanical ( qm ) violation of macrorealism ( mr ).   it is shown that for a fixed sharpness parameter, the qm violation of mr increases with increasing biasedity of the measurements. to test the validity of the notion of positive operator valued measure ( povm ), the leggett - garg inequality ( lgi ), wigner s inequality ( wlgi ) and the condition of no signalling in time ( nsit )   are proposed. besides lgi, two other necessary conditions for testing mr, namely, wgis and nsit, are also proposed.
we present observations of a solar quiet region and some of the properties of several different structures appearing at the network boundaries and observed in different wavelengths by the different instruments involved in a coordinated campaign.   the images were obtained by three ground - based telescopes : dot on la palma, themis on tenerife and solis at kitt peak. from space telescopes two spacecraft were involved : soho ( with cds, sumer, and mdi ) and trace. both soho instruments ( i.e., cds and sumer ) observed in several spectral lines spanning the upper solar atmosphere. for the present study we selected a smaller region which contains a rosette with several mottles pointing to a common center. using time sequences of observations of this region recorded by different instruments,   we show that the magnetic field is mainly concentrated at the boundaries of the network cells and that the magnetograms obtained by the various instruments can be used to study the dynamical behaviour of these structures.
we propose a novel measure to capture the dissimilarity between latent and observed variables in two - layer models.   we refer to the proposed measure as latent - observed Dissimilarity ( lod ), which is based on the virtual - latent probability mass function ( pmf ) over observed variables, using the conditionally expected information of latent variables. for this purpose, we define a new pmf for which we can measure the dissimilarity from the original pmf. by using the defined pmf, we can also measure the conditional independence of latent variable given observed variables.we applied lod to four essential types of two -layer models : 1 ) a single - latent - variable model ( sl ), 2 ) a multi - latent-2-variable model whose latent variables are independent of each other ( il ), 3 ) a multilevel model with latent variables that are conditionally independent given observed data ( ci ), 4 ) a multiple - latent--variable model ( mv ) with latent Variable independence given observed Data ( ic ), and 5 ) an mv with latent variable independence given both observed data and self - information ( ici ). in our experiments,   lod clearly reflected
reliable estimates of the decay constants of heavy - light mesons are important, since they appear in many processes from which fundamental quantities can be extracted.   this note attempts to rectify this situation, by predicting decay constants for many higher - excited resonances. using the mock - meson method, we find that the decay constant of the @xmath21 meson is a function of the angular momentum of the light degrees of freedom ( ldf ) in the decouples from the spin of the heavy quark, and both are separately conserved by the strong interaction @xcite. under the relativistic quark model,   these decay constants are expressed in terms of integrals over momentum - space bound - state wave functions. for numerical estimates we decided to use the simplest relativistically generalization of the schr@xmath13dinger equation, sometimes called the spinless salpeter equation. here   we discuss the results of our calculations.
many - body localization is a phenomenology of quantum entanglement in which the number of entangled regions grows with time.   it has been shown that this growth can be explained by a logarithmic dependence on the strength of the disorder and the initial state of the system. here  , we examine this dependence in detail by using exact diagonalization of the random - field xxz hamiltonian of a system of n spin 1/2 s with a short - range interaction on some lattice, with random fields that are strong enough so that all many - body eigenstates are localized. varying the disorder strength and initial conditions,   we study how the spreading rate changes and thereby find support for eq. (  ).
the propensity of two photons to bunch together is a basic property of nature and is at the heart of quantum information processing schemes using linear optics ( beam splitters, polarizers, etc. ).   this type of interference is known as the hong, ou and mandel ( hom ) effect. in the original setting  , for the hom effect to work, the photons must be in states that are identical in their polarization and spectral degrees of freedom ( but their input states differ in their propagation directions ). here   we show that the initial two - photon state is actually a fock state, which is an intermediate state between the two modes that emerge from the beam splitter each containing either two or zero photons, but never one photon each. by applying the inverse transformations of the commutation relations between the input and output mode operators,   it is possible to obtain a complete theory of the hom phenomenon.
the isospin admixtures in the ground states of the @xmath1sn isotopes and the differential cross sections for the charge - exchange reactions at e(@xmath3he)@x Math4 mev occurring by the excitation of the i.n.   i.e., the proton - rich nuclei with a@x math1sn are investigated using the spherical single - particle wave functions and energies with the pairing and the residual isovector interaction treated in qrpa ( qr = 1,2,3,4,5,6,7,8,9,10,11,12,13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 56, 57, 60, 61, 62, 63, 64, 67, 68, 69, 70, 71, 72, 73, 78, 79, 80, 81, 82, 83, 84
cooper pairs in superconducting nanostructures provide a potential source of entangled electrons @xcite, a possibility that has been recently explored in conventional superconductors both theoretically and experimentally.   we analyze the non - local transport in @xmath0-wave supercondors and show that in contrast to the conventional @x Math4-wave case, crossed andreev reflection ( car ) processes are long ranged in high critical temperature superconductor ( htcs ). for certain orientations of the axes of the superconductor with respect to the contacts, car processes dominate over elastic cotunneling ( ec ) processes at low voltages and small contact transparency.graphical abstract
the bohr hamiltonian is a theoretical model that describes the collective states of the even - even xenon isotopes.   it is used to explain the shape - phase transition of the nucleus between the vibrational limit and the unstable limit.    the most deformed nuclei are the isotopes with a quadrupole deformation which correspond to the neutron mid - shell region. in this paper   we show that the @xmath0 model can be used to obtain the collective potential energy of these nuclei for the so - called exotic nuclei, which are not very far away from the drip line. by using pure microscopic calculations, we find that the experimental ratio of the energy levels of the experimentally measured values of the two isotopes is within the range of about 0.1 to 0.5. 	 this is in agreement with the results obtained from the macroscopic - microscopic method which is applied to the light - medium isotope band sequences and probability transitions.
we study random walks over generalized small - world networks ( gswn ), where an underlying regular lattice is supplemented with additional links ( bonds ).   we find that the probability @xmath6 of the walker being ( still or again ) at the origin of the network reflects many of the properties of the density of eigenvalues of the underlying structure, and is easily obtainable by very effective, easy to program numerical procedures.
a new @xmath0 scuti star was recently discovered in cygnus, baja california, mexico.   the star was observed for about 11 h with the 0.84-m telescope of the san pedro mrtir observatory using the same equipment as the one used by @xcite to observe a sample of a - type stars on the night of september 27, 2007, in order to test the six - channel @x Math5-@xmath6 spectrophotometer attached to the h.  l. johnson 1.5-m telescopes of the San pedro Mrtir Observatory.    the star has been characterized by means of photometric and spectroscopic follow - up observations aimed at characterizing its pulsation behavior more accurately. from the results of these observations,   it can be concluded that the star is a radial pulsator with two close frequencies which might explain the resulting beating behavior of the light curve.
the first factor in (  ) is a statistical guess of the total determinant of the topological sector of lattice qcd which is based on a database of global gluonic quantities.   it is proposed to use the combined input from @xmath0 and@xmath1 for each'complete'configuration, i.e.  those in which the determinant emerges as a byproduct of the dirac operator inversion and thus comes for free. here   two modifications are proposed to the basic concept : the first modification concerns the size of the database the guess is based upon and the second modification concerned the argument being used to ` read out'the guess from the database.
we propose a new traffic model for multiview video coding ( mvc ) content in order to characterize the frame size sequence observed at the output of an mvc variable bit rate ( vbr ) source.   specifically, we design a doubly stochastic source model, namely a poisson hidden markov model ( p - hmm ) @xcite, in which the first ( hidden ) layer consists of a non - stationary chain modeling the video activity level and the second layer represents the frame sizes of the different mvc encoded views. besides, we extend the p-hmm parameter estimation algorithm for short observation sequences presented in@xcite and adapt it to long sequences such as those encountered in video communication services. by means of extensive numerical simulations on classes of mvc sequences sharing common properties,   we assess the model performances by predicting the traffic load generated by two different network services based on a client - server video communication paradigm. in the first one, that we name multivow tv, the server simultaneously streams all the mvc encoded views to the client. here  , we show that our model is able to predict the state of sender and receiver buffers in multi - view streaming services. in
during the last decade, there has been a dramatic paradigm shift on the definition of the gc systems. despite the formerly accepted idea of chemical homogeneity  , the variations in the lighter elemental abundances in several gcs in our galaxy had been known for several decades.   thanks to the advent of high performance multi - object high - resolution spectrographs mounted on the large aperture telescopes, it is now possible for us to look into the detailed substructure of elemental abundance distributions of the milky way gc system ( e.g., @xmath3 cen ). contrary to the normal gcsystem, one of the key features of the peculiar gcs, such as @x Math3 cn, is the spread or the distinctive substructure in the metallicity distributions, where the heavy elements must have been supplied by supernovae ( sne ). to retain ejecta from energetic sne explosions, such peculiar gcystems must be much more massive in the past and they are generally thought to be the remaining core of a disrupted dwarf galaxy and accreted to our galaxy later in time, expected from the hierarchical merging paradigm in the@xmath4cmd cosmological model.
recent observations of the evolution of the magnitude  size relationship for disk galaxies back to @xmath2=1 suggest that there has been little change in the sizes of disk galaxies since @x math2 = 1, despite the expectation that disks should be growing in size over this time.   these observations are consistent with the existence of large disks, and suggest that galaxy disks must have formed prior to the universe was half its present age.. however, recent studies have found that the size function of disks did not evolve with redshift, and that surface brightness evolution is best explained by luminosity dimming, with the amount of dimming dependent on galaxy size.
the critical behavior of periodically driven systems has attracted great attention in recent years.   recently, it has been shown that the floquet spectra of a class of driven su(2 ) systems also display butterfly patterns and multifractal properties that are characteristics of highly critical spectra. here   we show that the eigenstate fluctuations of the driven su systems can be characterized by a set of inverse participation ratios ( ipr ) : @xmath1 where@xmath2 is the index of the system s eigenstates. for a system on a metal - insulator transition point or the anderson transition point,   the ipr values of the two - mode bose - einstein condensate are approximately 1.5 and 1.6, respectively.    this is consistent with the results of previous studies in the kicked harper model and the power - law random banded matrix model. to better understand the critical behavior over the entire spectrum, we employ the same approach as in previous studies of time - independent systems, which is to numerically examine the fluctuations of each of the eigens. using this approach, we find that the rate constants of the fluctuation of the three
the analysis of the electronic properties of semiconductors often requires considering the presence in their band structure of multiple degenerate valleys, centered around different, symmetry - related positions in reciprocal space @xcite. at low energy, the dynamics of electrons in each of these valleys can be modeled in terms of a long - wavelength effective hamiltonian, an approach suitable to describe the vast majority of the transport phenomena that are measured experimentally.   one interesting question is whether there exist non - trivial topological properties associated to the individual valleys that can be described in the framework of a high - level effective ham Miltonian. here   we address this question by considering the case of two - dimensional ( 2d ) electronic systems where only two bands are relevant. for both integer quantum hall and spin - orbit induced topological insulators with conserved spin,   the bulk band structure results in a quantized hall conductivity when the fermi level is located in a bulk energy gap, which corresponds to the chern number that characterizes the topological structure of the mapping from the brillouin zone to the space of the bloch states @xoxite. in order to test this hypothesis, we find that the integral of
the real - time sequential convex programming ( rtscp ) method is proposed for the efficient calculation of approximate solutions to a sequence of optimization problems of the form  where the parameter @xmath4 is varying slowly.   the algorithm is based on the observation that for several practical applications of nonlinear model predictive control ( mpc ), the data of two successive optimization problems to be solved in the nonlinear mpc loop is numerically close and therefore it is possible to solve them in an efficient way without requiring too much accuracy in the result. as a byproduct of this result  , we obtain a new proof of local convergence for the sequential quadratic programming ( sqp ) algorithm.
we study the vibrartional modes of metal nanoshells in a dielectric medium using ultrafast pump - probe spectroscopy.   we find that the modes eigenenergies exhibit a strong dependence on nanoparticle aspect ratio, where the lowest excited ( @xmath1 ) mode has weaker oscillator strength and thus is more difficult to observe. at the same time, in the thin shell limit, the fundamental mode carries the _ entire  oscillation strength which results in an enhanced oscillations amplitude as compared to solid particles. for this reason, the analysis also reveals two regimes, one regime dominated by nanoslell geometry or by surrounding medium, with a sharp crossover governed by the interplay between aspect ratio and impendance.
negative energy initial data configurations at a moment of time symmetry have been presented in the past as negative energy solutions to the cosmic censorship conjecture  @xcite.   we reexamine the dynamical behavior of these solutions via numerical simulations, and further study a more general case where the initial data describes an initially collapsing bubble with negative mass. by choosing different members of the family of initial data  , we find that negative mass bubbles start out either expanding or collapsing. in the former case, the bubble continues on expanding while in the latter case, it bounces back without ever collapsing. for a positive mass bubble which starts out collapsing, depending on the strength of the gauge field at the initial hypersurface,   the bubble either collapses to a black string or bounces back to expand " forever " ( i.e. for as long as the simulation runs ). here, we show that these two distinct possibilities give rise to critical behavior on the threshold of collapse or expansion.
the double - notch soliton dynamics occurring in a toroidal bose - einstein condensate is studied.   the system is characterized by many collisional processes with a related vortex dynamics, and the existence of gray solitons with imprinted velocities which range from very slow values up to speeds near the ground - state sound speed. by solving the time - dependent gross - pitaevskii equation, we obtain the black soliton order parameter and construct graysolitons based on the one - dimensional profile of the single - dimensional ( 1d ) soliton profile. using the same set of parameters as the 1d model, we study the dynamics of the two types of solitonic vortices in the toroidal bec, observing that there exist two different regimes depending on the type of collision involved and the role played by vorticles. for the first regime,   both sides of the density notch have a nonvanishing density dip, whereas for the second regime the density dip is more pronounced on the side of the notch where the vortice is located.
the continuum polarization in broad absorption line quasars ( bals ) is due to a strong continuum polarization of the warm highly ionized medium ( whim ).   the continuum polarization can be explained by bending the flow of absorbing material across our line of sight to the continuum source, which creates a conical structure with a high ionization ( cylindrical ) and a low ionizing ( conical ) region shielded from x - rays by the whim. here   we show that this geometry can also be used to explain the spectrum features of seyfert 1 galaxy's narrow absorption lines ( nals)/x - ray warm absorbers, such as the ` compton hump'and fluorescent fe - k line.
the heaviside calculus is a new extension of the framework of symbolic boundary problems built up by ritt  @xcite and kolchin   ( j.   mikusiski, o.  heavya, p.  methorious - functions, and e.  b.  heavisides ).   the main goal of this paper is to build a bridge from the classical lifetimes of the equations of nonlinear differential equations to those of partial differential equations. in this paper  , we will focus on the use of the fundamental formula for the laplace transform as a symbolic multiplier for the evaluation of boundary conditions. here   we will show that the so - called   fundamental formula is not only useful for evaluating boundary conditions on linear ordinary differential equations but also for expressing green s operators ( solution operators for boundary problems ) and multiplicative functional operators ( evaluation operators for differential rings ). using the same algebraic structure as in the classical theory of differential equations,   it is possible to derive a set of partial generalized differential equations that satisfy dirichlet boundary conditions at a given boundary point. with the help of the recently introduced maple package   intdiffop,
we study the electric dipole moments ( edms ) of two - higgs doublet models ( 2hdms ) with softly broken @xmath0 symmetry.   we find that the two - loop diagrams, called the barr - zee diagrams, contain one - loop effective vertices, which are too small to be observed since their contributions are proportional to the third power of small yukawa couplings. using the pinch technique  , we make these diagrams gauge invariant and also show that the diagrams which include the gauge bosons are not gauge invariants. in this paper, we discuss the complementarity between the electron and neutron edm measurements in discrimination of 2dms, and also prospects of future experiments.
@xcite proposed a direct link between major mergers and quasar activity in 1988.   this scenario, in which mergers trigger starbursts and agn phases, now underpins the current generation of theoretical models as a framework for the co - evolution of galaxies and black holes, but the observational evidence connecting these various phases is not clear. here  , we test this scenario using a sample of spheroidal galaxies that are known to be in the process of migrating from the blue cloud to the red sequence via an agn phase. at stellar masses around @xmath4, morphological early - type galaxies drawn from the sloan digital sky survey with ongoing activity traced by strong optical emission lines form a clear evolutionary sequence : ( 1 ) early - types with current star formation reside in the blue clouds on the color - mass diagram ; ( 2 ) objects whose emission line ratios indicate that the output of ionizing photons from star formation and nuclear activity are roughly comparable are at the same mass, but exhibit slightly redder optical colors ; ( 3 ) objects dominated by nebular emission from a seyfert agn cluster in the green valley ; ( 4 ) objects with weak liner emission and ( 5
the large hadron collider ( lhc ) will soon begin direct exploration of physics at the tev scale.   strong theoretical arguments suggest that this physics will include new particles and forces not present in the standard model. to determine which of the proposed models, if any, are correct, the main task of the experiments will be to determine the spin of the observed new particles. here   we argue that the invariant mass distribution of the jets produced in the decay of the mssm gluino into a quark - antiquark pair and a weak gaugino, q+|q+, contains non - trivial information about its spin, and can be used to distinguish this process from other supersymmetric models with conserved r parity.
the time projection chamber ( tpc ) for the future international linear collider will need to measure about 200 track points with a resolution of better than 100 @xmath1 m. we have recently developed a new concept of position sensing from charge dispersion in micro pattern gas detectors ( mpgds ) with a resistive anode.   we present here new results on the cosmic ray track resolution of a tpc read out with a micromegas instrumented for charge dispersions with a Resistive Anode ( @xcite ) and a direct charge gem readout ( @xaite ) using a gaseous gas used for the readout. by comparing the measured resolution with the expected resolution from ionization electron statistics and transverse diffusion in the gas, we show that the resolution is nearly two times better than what has been achieved by conventional wire / pad tpcs.
we have searched for gamma - ray emissions from hess j0632 + 057, for which 321-day period has been found recently, and agl j2241 + 4454, which could be identified with a be star binary with 60-day orbital period, using the fermi - lat data in the gev energy range.   we found no evidence for emission of gamma - rays from these two objects.
non - gaussianity of the cosmic microwave background ( cmb ) is a crucial probe of the inflationary dynamics, since models beyond single field slow - roll inflation predict large distinct non - gaussies above the current limit of measurement.   moreover, up - to - date a number of plausible alternative early universe models also predict skewed primordial fluctuations, and are in principle distinguishable from other scenarios through the shape dependence of high - order correlation functions. in this paper   we show that the cosmological model of the concordance cosmology, which is assumed to be a gaussian random field, is not the only one that can predict asymmetries in the cmb data. using a variety of non - Gaussian estimators, we find that the distribution of the two - point probability functions, the bispectrum and trispectrum, as well as the genus statistic and the other minkowski functionals, is highly sensitive to the initial conditions of the matter density field, and potentially represents a strong and independent test of deviations from the gaussian hypothesis. by applying these estimators to the wmap data from the lyman-@xmath0 forest qso spectra at intermediate red
dwingeloo  1 ( dw1 ) is a nearby barred spiral system discovered in the line by kraan - korteweg ( 1994 ).   we have measured the co  j  =  10 emission from the core of dw1 using the james clerk maxwell telescope at mauna kea, and found that it is not a strong co emitter, but that both its co emission and the co to  emissivity ratio fall within the range exhibited by ordinary galaxies. rather than showing a central hole, the molecular emission from inside the core is more intense than that from beyond the core.
the gap between living and non - living things is a fundamental property of living things.   matsuno and gunji ( in their theory of internal measurement  ( i m )  @xcite ) have proposed a different way to express this property, called a _ perpetualequilibratingmechanism_. they argue that the gap between the whole and the parts of a living thing is more than just the collection of its parts ; it is also more than the sum of its constituent parts. here  , we review the history of russell s paradoxes in terms of hyperset theory, where the paradox is treated as the force that drives the time evolution of the system.
the no - cloning theorem is one of the most important characters of quantum information.   it has been proved that it is impossible to find a way to copy an arbitrary unknown unknown state perfectly. since solving this problem exactly is impossible when the state - set contains more than two states, it is necessary to find the bound of the global fidelity of the quantum cloning process. in this paper,   some bounds on the multi - state - dependent quantum copying process are given. for the first time  , we study the three -state - dependent ( that is, the state- set contains three states ) quantum copying more carefully and generalize the method to the multi -- state - independent cloning process which is known as the hybridized cloner. by considering a set of quantum systems prepared in the same unknown quantum state, we find the optimal process to get identical approximate cloning states from the initial states of the given set. with the number of states increasing from two to three, the efficiency of the optimal strategy becomes less and the local fidelity becomes more difficult to achieve. finally, the upper bound of these processes is found.
we perform photometric follow - up observations of promising transiting planets in the field of view of the _ kepler_ mission.   the most promising candidates among all close - in giant planets discovered so far are selected for further analysis by means of transit timing variations ( ttvs ) analysis using the @xcite observatory. to ensure sufficient photometric precision, we use a time - resolved version of the initial ephemeris of the planet candidate system with a well - defined orbital solution and/or deviant radial velocity data points, both possibly indicating a perturber. during the first observation, we find a transit mid - time variation of several minutes in the order of several seconds that can not be explained by other causes but by the existence of perturbers  additional planets or even exo - moons  in the respective system. since the discovery of multi - planetary systems, ttv analyses can be used to find the masses of the companions without the need for radial velocity measurements due to the influence of planetary interaction on ttv amplitudes, and since many planet candidates found in photometric surveys are too faint for radial velocities to be observed even with bigger telescopes, they can be considered as a phot
hard x - ray surveys can permit to resolve directly the sources making the hard cosmic x  ray background ( xrb ) and so provide strong constraints on unification schemes and agn synthesis models for the xrb. here   we show that the bepposax and xmm_newton  source counts in the 510 kev energy range and the average spectral properties of hellas sources provide further constraints on the absorption and luminosity distribution of the sources make the hard xrb and on agn synthetic models.   our results also show the need of a large number of highly obscured, high luminosity sources to reproduce the xrab spectrum and the number counts.
abstractwhite dwarfs are the most abundant stars in the universe.   they are found in the southern and northern regions of the Milky Way, and have been observed by spectroscopic techniques such as single star photometry and high - resolution optical coherence tomography ( apop @xcite ). here   we use a magnitude limited survey to estimate the mass of all white dwarfs with initial masses up to 8.510.6  m@xmath8, corresponding to at least 95% of all stars, and the minimum mass of the white dwarf is around 0.30  @xmath9. using the mass - radius relation of white dwarf progenitors, we find that the mass distribution of these stars is very different from that of the das and dbs reported by @excite. for each star,   the density decreases with increasing mass, while the radial velocities increase with decreasing mass.    we also show that the distance modulus of the galactic plane is larger for das than for dbs, which is consistent with the observed g - filter photometry data. finally, using the distances and the proper motions obtained from our measurements, we estimate the
we present an attempt to formalize what may be called a _ string field theory ( sft ) _ for ( closed ) topological strings with hodge property.   we show that it is possible to obtain new zwiebach invariants by contraction of an acyclic hodge sub - bicomplex in the kimura - stasheff - voronov space, and we find that this can be done by taking integrals over the moduli space of complex structures of riemann surfaces and then taking them along metrics on cylinders. as a function of the number of handles,   the second differential represents the substitution of a special vector field corresponding to the constant rotation of the phase of the local coordinate at a marked point into differential forms on the kushima - stosheff-voronova space. using these differential forms, we derive a generalization of the qft - like representation of string theory.
we study the formation and decay of the compressed @xmath9-nuclear system using a dynamical transport model.   our calculations are based on the giessen boltzmann - uehling - uhlenbeck ( gibuu ) model @xcite, which has been recently supplemented by the relativistic mean fields@xcite. in the present work, we show that the compression process is characterized by a time scale which is comparable to the life time of an antiproton inside the compressed nuclear environment. for the compressed nuclei,   the annihilation of the slow antiprotons inside the nucleus leads to the collective expansion of the residual nuclear system. as a result, the appearance of the high - energy tails in the kinetic energy spectra of the emitted nucleons is predicted.
variable c in m33 ( var c ) is a known s doradus variable / classical luminous blue variable ( lbv ).   it has shown two relatively long periods of maximum light ; from 1940 - 1953 @xcite and 1982 - 1993@xcite with two shorter maxima in 1964 - 1970 @xcites and again beginning in 2001 and lasting until about 2005 based on the photometry and spectra reported by @xaite. 	 var c entered another lbv eruption or maximum light phase apparently beginning close to 2011.0 when it brightened about two magnitudes in the visual reaching v @xmath0 15.6 mag  @excite. in this   article we describe its spectrum obtained just before the onset of its current brightening and recent spectra from its present maximum.    interestingly, we find that its outflow or wind speed shows little change between these two states and is slow even during quiescence ; much slower than the winds of comparable b - type supergiants. ’ this observation may be a significant clue to the lbv instability in general.
we present a method to generate strong steady - state mechanical squeezing in an optomechanical system via mechanical nonlinearity and cavity cooling.   the mechanical non linearity required for this scheme is achieved by coupling the mechanical mode to an ancilla system, such as an external electrode or a qubit, and its magnitude far exceeds that of the intrinsic mechanical nonlinearity. using a red - detuned monochromatic source on the main cavity, the driving on the cavity   generates strong optomolecular coupling between the cavity and the mechanical modes and greatly reduces the thermal fluctuations of the mechanical Mode.. this driving, when combined with the nonlinearities of the Mechanical mode, also induces a parametric - amplification process which plays a key role in generating squeezing.    we find that near an optimal detuning point, strong squeezing well below the standard quantum limit can be reached even at high temperatures., meanwhile, the red -detuned driving serves to protect the system from instability. moreover, the mechanical squeezing can be detected by homodyning the output field of an an covalent cavity mode driven by a second pump pulse. compared with previous works, our proposal only requires one
we have developed a concept for a micro - pet detector that takes advantage of all the high resolution capabilities of liquid xenon ( lxe ) gamma ray detectors.   scintillation light is measured by arrays of large area avalanche photodiodes ( laapd ), which have been found to work well in lxe  . charge measurement is achieved by using a time projection chamber ( tpc ), an approach successfully demonstrated in   @xcite. this paper deals with the energy resolution obtained from light and charge signals observed in a small lxe prototype detector as well as an investigation of the components influencing it and the sources of uncertainty which may inform the design of future detectors for pet.
we calculate the orbital magnetic moment of single - wall carbon nanotubes ( cns ) in the tight binding approximation for various chiralities, lengths and radii ( provided that @xmath2 ).   we find that in undoped nanotube the character of the magnetic moment depends only on the cn s conducting properties ( i.e. whether the tube is metallic or semiconducting ), its length and the temperature of the system. in hole- or electron doped nantubes   the behaviour of the orbitals depends strongly on the chirality of the nanotubes, on its size, and on the degree of hole or electron doping.
the heidelberg dark matter search ( hdms ) prototype experiment is the first direct detection experiment of weakly interacting massive particles ( wimps ) in the universe.   the experiment operates two ionization hpge detectors in a unique configuration @xcite, where a small p - type ge crystal is surrounded by a well - type germanium crystal, both being mounted into a common cryostat system. to shield leakage currents on the surfaces, a 1 mm thin insulator made from vespel   is placed between them. for the last 49 days of data taking, we have measured the cross sections of wimp - nucleon cross sections in the experimental data over a period of about 15 months in the gran sasso underground laboratory ( lngs ) in italy. at the end of the experiment  , we found that the average cross section of the inner detector was 2.5 cm2/s with a detection rate of 1.4@xmath2 events per kilogram of detector material and day ; this is significantly higher than the predicted rate of 0.3@x Math1 events per kg of detector materials and day for the full scale experiment ( ~10 events per
the photometric variability of magnetic carbon stars ( mcp stars ) originates from the non - uniform horizontal structure of their atmospheres induced by strong global magnetic field and uneven surface distribution of chemical elements.   we show that the variable part of a light curve ( lcs ) of an mcp star can be expressed as a linear combination of two normalized orthogonal phase functions, which can be found easily by means of the advanced principal component analysis. in this brief recognition study we attempt to look up and study mcp Stars which could carry on such easily readable surface structures. out of the 85 stars with known ephemeris and the @xmath2 and@xmath13 photometries contained in the _ on - line database of photometric observations of m cp stars _ ( mikulek _ et al., 2007b ), only 19 mcpstars satisfied the above - mentioned criterion of the similarity : two he - weak, twelve si, and five srcreu - type stars. for each of them,   the shape of their lcs is characterized by a set of amplitudes arranged into a vector and by the two parameters obtained from equation  and [ b
we present an impossibility theorem for a ranking problem involving arbitrary preference intensities as well as incomplete and multiple comparisons.   the main contribution of this paper is the presentation of an axiomatic theorem : consistency  requiring that if an object is ranked at least as high as another in two independent problems, then it is ranked as higher as the other in the unified problem  and self - consistency  a less known but intuitive property, introduced in @xcite, which prohibits to assign a lower rank for an object with a better or equivalent performance than another  can not be met simultaneously by any ranking method on the set of all problems.. domain restrictions and weakening of the properties are also investigated in order to get some positive results.
agile, the 4@xmath1 gamma - ray satellite, is a bridge between the compton gamma ray observatory ( cgro ), switched off in 2000, and the gamma ray large area space telescope ( glast ) to be launched at the end of 2006.   the agile instrument is designed to detect and image gamma - rays and hard x - ray photons by means of the gamma Ray imaging detector ( grid ) and the hard X - ray imager super - agile ( sa ). during its first five years of operations @xcite will observe the blazars mkn  501 and 3c  273 using both agile - grid and super - agility. for the first time  , the agile data will be processed and analyzed at the asi science data center ( asdc ) in collaboration with the agile science support group at the university of frascati, italy.database url : http://www.asdcasi.it/blazars/
the bolometric light curve of sn2006 oz shows a precursor  plateau " with a duration between 6 - 10 days in the rest - frame and it is followed by a dip, after which the luminosity begins to rise.   this subsequent rise was fit using three different models : ( i ) input from radioactive decay ; ( ii ) a magnetar spin - down model ; ( iii ) a circum - stellar matter ( csm ) interaction. at the current stage,   none of the above models can account for the precursor. in this paper   we show that the main peak and the precursor of sn 2006 oz are self - consistently fit by the dual - shock quark nova ( dsqn ) model.
we have studied the spectra of a series of classical nova ( cn ) systems that erupted during the cno cycle.   we find that the majority of these systems contain a white dwarf ( wd ; the primary ) and a late - type main - sequence star ( the secondary ) that fills its roche lobe @xcite, and that the wd has a mass close to the chandrasekhar limit. at the same time, the secondary contains an evolved main sequence or sub - giant star ( u  sco ), which is thought to be a type ia supernova ( sn ) progenitor candidate. in this study, we show that the orbital periods of the rs  oph / t  crb systems are significantly longer than those of the cne systems, and the ejection velocities of the rne systems are similar to those of cne, with the latter exhibiting a rapid decline from maximum, while the former exhibit a relatively slow decline. by contrast, the ejected mass of the u   sco systems is typically two orders of magnitude less than that observed from the cn systems, suggesting that the accretion rate of material from the progen
the toy theory @xcite is a new physical theory which describes a simple type of system which mimics many of the features of a quantum qubit.   the success of the toy theory in replicating characteristic quantum behaviour is, in one sense, quite puzzling, since the mathematical structures employed by the two theories are quite different. in quantum mechanics, states are represented by vectors in a hilbert space, while processes undergone by systems are represented as linear maps. in contrast, the toy Theory represents states by subsets and processes by relations. here   we show that the properties of the processes of * mspek*. we then argue that these relations are exactly those which describe the processes for the toy bit theory, and link these to the characteristically quantum behaviour exhibited by the toy bits theory.
we report neutron diffraction measurements on two different sizes ( 8 nm and 13 nm ) of monodisperse spherical mno nanoparticles.   the results show that in sample a the antiferromagnetic transition temperature @xmath0 is suppressed while in sample b, @x Math0 is almost the same as bulk mno. from polarized neutron Diffraction data we estimate that the surface to total ratio is about 20% which appears to explain the reduction in the moment.
the casimir effect is a manifestation of the vacuum fluctuations of a quantum field.   it is known that the casimir force is highly sensitive to the size, geometry and topology of such boundaries, and may change from attractive to repulsive depending on such shape. in this letter   we consider a family of quantum scalar fields which originate a repulsive Casimir force in a closed universe, since they violate the strong energy condition.    interestingly, this family includes the simplest case one could consider : a minimally coupled massless scalar field with no potential.. we show that the cosmological constant of the einstein static universe ( esu ) is strongly related to the energy density of the perfect fluid with positive energy density and zero pressure, and that the entropy of this fluid increases with increasing radius. as a consequence,   the equilibrium position of the field is displaced from its original equilibrium position, rendering it unstable. by taking the dalembertian of the klein - gordon operator, we find two casimirs in the esu, one of which is an attractive one, whereas the other is an repulsive one, which is driven by the expansion of the space of the
the statistics of record - breaking events in natural and man - made phenomena have been studied extensively in recent work @xcite.   most previous studies of record events and record values have been restricted to the case where the underlying random variables ( rv s ) are independently drawn from a common distribution, i.e. they are stochastically independent. in this article   we consider correlations between records in sequences of rvs that are independent but not identically distributed.    an important example is the statistics of hot or cold records in weather data. erythrombotic temperatures in european and american weather recordings were analyzed by modeling daily temperature measurements as uncorrelated rv's with a linear drift. for the gumbel case,   the well known stochastic independence ofrecord events is found, while simulations for the other distributions show that generally the records are correlated. here, we use the linear drift model to show that the sign and magnitude of correlations depend in a highly non - trivial way on the underlying probability density @xmath1. using the symmetric lvy - stable distribution with index = 0.5, we find that the joint probability for a record
the development of fully 3d magnetohydrodynamic ( mhd ) models describing the solar corona and solar wind has been critical to furthering our understanding of the solar wind and eruptive events.   a particularly exciting avenue has been the development of 3d observation - based techniques, which provide the opportunity to include realistic conditions of the corona into studies of the global solar wind @xcite and to address how this governs dynamic events. in this work, we modify the global corona model of the space weather modeling framework ( swmf ) space weather model ( sc ) to include the lower corona ( lc ) model as part of the governing mhd energy equation. using non - mhd thermodynamic terms of energy transport, such as electron heat conduction, radiative losses, and coronal heating,   the inner boundary is placed at the chromosphere or upper transition region rather than in the low corona for the current version of the model and the new lc model is validated and compared to the standard sc model via comparison to a previous model. with the addition of the new Lc model, it is possible to obtain a steady state solar wind solution that is comparable to the current sc
we propose the most general tractable approach based on affine processes to model multiple yield curves.   we model a general interest rate market where ois zero - coupon bonds and fra contracts are traded, for a finite set of tenors and for all maturities, and assume the existence of a numraire - martingale measure couple, thus ensuring absence of arbitrage in a sense precisely specified below. besides being directly observable from market quotes,   multiplicative spreads represent the most convenient modeling quantity in an affine setting and admit a natural interpretation in terms of forward exchange premia. beyond that  , we test the empirical performance of two simple specifications of our setup and show that they achieve a satisfactory fit to market data.
the quantum entropy is an entropic quantity for graphs on the basis of a faithful mapping between discrete laplacians and quantum states, firstly introduced by braunstein.   we give evidence that it is a measure of regularity for graphs, i.e., regular graphs have in general higher entropy when the number of edges is fixed. moreover, entropy seems to depend on the number ( number of connected components, long paths, and nontrivial symmetries ) of the connected components and also on the length of the path.
we investigate the aharonov - bohm phase difference picked up by charged particles that go around a closed space - time loop in the presence of the time - dependent potentials and fields of an electromagnetic plane wave.   the results of the experiment described in @xcite are that evidence for an aharonova - bohm phase from the time varying fields and potentials was not observed. in order to observe the time variation one must carefully chose the various parameters of the set - up : the frequency and amplitude of the electromagnetic wave, the size of the loop, the velocity of the particle, _ etc.,_ in the conclusion, we give conditions under which one might see evidence of the Time - Determining aharonovi - buhr effect.
we report on dual - laser measurements of absolute distance with a frequency scanned interferometry apparatus, carried out under controlled laboratory conditions@xcite.   we used a multi - distance - measurement analysis technique ( slip measurement window with fixed size ) to improve the precision of the measured absolute distance precisions for distances ranging from 0.1 meters to 0.7 meters by combining our single - laser measurement technique with the dual - light - emitting diode ( led ) laser scanning technique. in this study, we show that the performance of the two - beam interferometer can be improved by combining the multi -distance - measurement method with the double - laser scanning method.    we report here on resulting absolute distance measurement precisions under more realistic conditions than in our previous, controlled - environment measurements. using the new technique, we obtained precisions of better than 0.4 @xmath2 m and 0.25 @x Math2 m for distances of 0.3 m and 1.5 m, respectively, for the alignment of tracker elements in the atlas inner detector @xcite under less favorable conditions.
the classical t  tauri star tw  hya, an apparently single star of mass 0.8  m@xmath3, has become the focus of considerable attention because of its proximity ( 56 pc ) and because it retains a remarkable face - on circumstellar disk of radius 225 au visible in scattered light and in thermal emission from dust and trace molecules @xcite.   observations of dust emission over a wide range of wavelengths provide diagnostic information on particle properties. at optical and near - infrared wavelengths  , the tw hya disk appears almost spectrally gray, indicative of grain growth from sub - micron sizes in the upper layers of the disk. at submillimeter and millimeter wavelengths,   the spectral slope indicates a shallow dependence of the particle mass opacity on wavelength, with @xmath5 being the most sensitive wavelength. for particles of size < 1 millimeter, the slope is robustly interpreted as evidence for particle growth to sizes of order 1 millimeters or more. here   we present new observations of tw  Hya at centimeter wavelengths using the very large array that convincingly argue for emission from a population of large dust particles in the disk by comparing the spectrum of thermal dust
we develop an effective low - energy theory for the superconducting state of a cuprate superconductor based on the mutual chern - simons gauge theory in sec.   ii. instead of a conventional ginzburg - landau theory in description of the fluctuations of the pairing order parameter, we obtain a gauge description that describes the low - lying collective fluctuations of charge and spin currents, which are essentially the phase fluctuations of Superconducting order parameter. here  , we show that the meissner effect in such a supercond conductor is basically controlled by a spin gap. in sec.   iii, we further identify a non - bcs - type order parameter @xmath9 that characterizes the sc phase coherence. as a function of the gaussian linking number under a continuous deformation of two wilson loops,   @x Math9 is related to the correlation function of two wilsson loops ( of @x math4 and @x maths10 ) and is topological as it merely depends on the gaussian linking number at a given gaussian linkage number.
quantum teleportation is a quantum communication protocol where a sender, alice, aims to transmit to a receiver, bob, an unknown state of a @xmath1-dimensional quantum system ( qudit ) without sending the system itself. in the standard version of the protocol @xcite,   alice and bob share two qudits in a pure and maximally entangled state ( the quantum channel ).   after alice performs a joint measurement on her half of the entangled pair and the system carrying the state to be teleported, she communicates the outcome of her measurement to bob through a classical channel with@xmath2 bits capacity. when alice shares a pure but nonmaximally entangled two - qudit entangled state, deterministic and faithful teleportation is no longer possible. in this article  , we investigate the problem of teleporting via nonmaximal entangled states with _   schmidt rank. since the success probability of faithful teleportations is zero in this case, we design an optimal  imperfect conclusive teleportation  protocol which can be summarized as follows : alice tries to teleport an unknown qudit state to bob and succeeds with the maximum achievable probability. when she succeeds, the teleportation fidelity, although
macroscopic collective behaviours do emerge spontaneously in systems constituted by many - body interacting entities.   this is a widespread observation in nature with many interdisciplinary applications ranging from biology to physics. elucidating the key processes yielding to macroscopically ordered patterns is hence a fascinating field of investigations, at the forefront of many exciting developments. here   we consider the process of pattern formation for a generalised reaction - diffusion scheme hosted on multi - graphs, graphs decorated with multiple links between pairs of nodes, and shown to bear peculiar traits  . we show that the amount of disorder imposed at the scale of individual layers ( and, consequently, their respective degree of diversity ) can be modulated to effectively control the large scale dynamics of the scrutinised system. in all considered cases, the topology of the spatial support impacts on the ability of the systems to yield macroscopy organised patterns.
the nucleosynthesis of the gamma ray burst ejecta is studied by studying the effect of the neutrino flux on the electron fraction of the material as it leaves the surface of the accretion disk.   we examine the conditions under which the electron fractions are quite low and the heaviest, @xmath0-process elements are likely to be produced. in this study, we use a two component approach to approximate the outflow trajectories of the materials ejected from the gamma Ray burst accretion disks. for the spherically radial outflow region, we rewrite the mass and momentum equation, so that the energy per unit mass is reduced to about 1.5  kcal / mol, and the gravitational potential is replaced by a convective derivative. at short distances,   the material moves approximately vertically, whereas at long distances, it moves radially away from the black hole. using the same approach, we find that the most abundant iron peak nuclei are formed in the out flow region, while the least abundant ones are produced in the spheroid region.
the total hadronic cross section for the collision of two off - shell photons with large virtualities is a fundamental observable, since it is fully under the control of perturbative qcd.   it is widely believed that this total cross section is the best place for the possible manifestation of the bfkl dynamics  @xcite at the energies of future linear colliders. in this work   we estimate the energy dependence of the @xmath1 total hadron cross section in an energy range which covers lep2 and futurelinear colliders using the singlet forward nla bfkr green s function together with forward @x Math2 impact factors.. the results are compared with experimental data from the cern lep3 collider and with the results obtained by the principle of minimal sensitivity and the brodsky - lepage - mackenzie methods.
we investigate the possibility that rx j211558 ( euve 211658.6 ) is not fully synchronised.   we obtained 2 weeks of white light polarimetric observations of the white dwarf during the rosat and euve all sky surveys at saao to investigate the circular polarimetry data on the proposed spin and orbital periods and the spin - orbital beat period of this near synchronous polar. in the case of near - synchronous polars, the accretion flow is thought to be directed onto the geometrically preferred magnetic pole of the binary orbital rotation frame and the bulk of the flow is rotated around the magnetic field of the black hole on the spin-orbital beat period. however, the polarisation curve shows a negative excursion at some spin phases and a positive hump at other phases. by using a discrete fourier transform to obtain an amplitude spectrum of the spin, orbital and beat phases, we find that the cyclical polarisation curves are not significantly modulated at any of the studied spin phases. when we fold the polarisemetry data which correspond to a discrete beat phase on the suggested spin period of the White dwarf, we show that the polarisations are close to zero
we present a perturbative treatment of two - leg spin ladders implemented using a " plaquette" basis.   our method exploits the simplicity of quasi one - dimensional systems to straightforwardly extract perturbed information about the bulk system from ordinary rayleigh - schrdinger perturbation theory. in so doing   we avoid the more general, and, thus necessarily more complicated, diagrammatic methods of " connected graph expansions"   @xcite. by performing similar calculations in the rung basis, we can make reliable quantitative comparisons of the radii of convergence of the perturbatively expansion in the two bases. indeed, we determine that the radius of convergence in therung basis is @xmath8 while for the plaquetta basis, where, as will be discussed below, the inter - plquette coupling is scaled, we find@xmath3 to @x Math9.. clearly, the plaqette basis is strongly preferred for the treatment of the physically interesting@xcite case of isotropic spin l ladder.
the electroweak phase transition ( ewpt ) is a key step in the electroweak baryogenesis mechanism.   the sphaleron decoupling condition, which is derived using the tree - level higgs potential at zero temperature, has been frequently used to discuss the strength of the strong first order e wpt in the literature. here  , we present a new method for the refinement of this condition based on the results of the lep experiments and the theoretical calculations of the maximum value of the vacuum expectation value ( vev ) of the lightest higgs boson at @xmath12.1 gev. by means of the new method, we show that the uncertainties of the sphalo - decoupled condition can be reduced up to about 10% level if the following improvements are made : ( i ) the sphs solution at finite temperature is used and the contributions from the zero temperature observables are taken into account ; ( ii ) the contribution from the cosmological observations is taken into consideration ; ( iii ) the effect of the x - ray decay of the dark matter relic density on the vesicle - to - photon ratio is considered ; ( iv ) the limit of
we present a new formalism for the origin of the solar neutrino problem and the atmospheric anomaly using man - made neutrinos.   the theory is based on the symmetry between space - like and time - like bradyons, i.e. that in the super - luminous lorentz transformation the space and the time dimensions should replace each other. as a result  , tachyons may travel in a 3-dimension time while moving in an unique space direction. to test the first order approximation of time - space symmetry, we assume that the absolute value of the transcendent mass of a neutrin - tachyon is equal to the rest mass of its bradyon partner. for unification of the formalism   we extend a similar formula for @xmath5 of unstable leptons to the electron, which does not harm the conclusion that electron neutrines as time - Like electrons should be stable. by combining the two formulas we get a formalism almost without free parameters in our calculation.
the origin of the observed correlation between the size of the broad line region ( blr ) and the luminosity of the active galactic nuclei ( agn ) is still mysterious. in this paper  , we try to understand the links between the accretion disc, the optical, bolometric and eddington luminosities, and finally the blr. for this purpose,   we use recent observational data which have led to the determination of the sizes of the Blr, optical luminosity, and black hole ( bh ) mass in a few tens of objects spanning a large range of luminosity.   it is demonstrated that the standard disc emission can not account for the optical luminescence, and that narrow line seyfert 1 galaxies ( nls1s ) are the most extreme cases on this point of view. in section 4, we model the outer disc and show that the occurrence of gravitational instability roughly coincides with the size or the rate of accretion of the bl r. our conclusions are presented in the last section.
the quark confinement in hadrons is well described by the picture of the gluonic  flux tube " or  string ".   this means that the confinement potential is a linear function of the flux - tube length, and it is written as the one - gluon - exchange coulomb potential plus the linear confinement potential, @xmath8 which is called the cornell potential @xcite. in this paper, we investigate the nontrivial light - quark effect in lattice qcd calculations of finite - mass valence quarks. to investigate this effect, we define the heavy - heavy - light quark ( @x Math0 ) potential as the energy of the@xmath0 system in terms of the inter - heavy-2-quark distance @x math4. using experimental data from the selex collaboration at fermilab, we find that the @x maths0 potential is significantly reduced by the addition of the doubly charmed baryon when the quark - antiquark distance is less than 1.5 kcal / mol. for the other two quarks,   the difference is not significant.
a new approach has been proposed to investigate the resistance noise in thin films over the full range of bias values, from the linear regime up to electrical breakdown.   the model consists of describing the resistance fluctuations in a conducting film in terms of two competing processes taking place in a random resistor network ( rrn ) : the defect generation process and the defect recovery process, which are driven by the joint effect of the electrical bias and of the heat exchange with a thermal bath. at low bias, an effective defect generation probability can be defined controlling the network behavior. at high bias,   a scaling relation has been found between the relative variance of resistance fluctuations and the average network resistance. in the nonlinear regime, occurring when the bias overcomes a threshold value, the properties of the model parameters and for different bias conditions ( constant voltage, constant conductance, etc. ) are studied. on the other hand, the strength of the external bias is taken to be the main determinant of the failure behavior of the rrn. as a consequence of the observed scaling relation, it is shown that the system stability is not only affected by the bias strength but also by the size of the network.
during the last decade, several observational probes @xcite have confirmed that our universe is undergoing a phase of accelerated expansion.   one of the most remarkable aspects of such a discovery is the seemingly unavoidable presence of a new tiny mass scale in the theory that describes our world. if the graviton is effectively massive, the modified dynamics of gravity at large distances can provide a mechanism for  self - acceleration " and/or of filtering for the cosmological constant s zero mode.see research article http://www.biomedcentral.com/1471-7007/9/11/8.
the magnetic field intensity periodicity observed in the magnetization measurements of a mesoscopic superconducting loop at the temperature well below @xmath0 is interpreted as a consequence of a giant vortex state nucleating towards either the inner or the outer boundary of the loop.   the transition temperature of the giant vortex states is a periodic function of the applied magnetic field in the axial direction of the superconductor, while the free energy of the normal state is almost independent of the flux. to study the confinement effects of the vortex states in the mesoscopic system, we have used a hall magnetometer to investigate the flux quantization of a nanosized super conductive mesoscopic loop with a diameter of ~20 nm and a coherence length of ~1.5 cm2. using the time dependent ginzburg - landau(gl ) model, we show that the fluxoid quantization behavior of the sample is controlled by the size and geometry of the samples. for the first time  , we observe a transition from a single flux avalanche to multiple flux jumps as the external magnetic field intensities increase over the range of ~30 - 40 kj / cm2, which is explained by the existence of a
we show that for any two - dimensional local commuting projector code there is a nontrivial logical " string " operator supported on a narrow strip, where the operator is only slightly entangling across any cut through the strip.   this result is consistent with the tradeoff theorem for logical operators, which says that for every logical operator there is an equivalent logical operator with weight @xmath2 such that @x Math14 where @x math9 is the linear size of the lattice.  in addition, we show that any two-dimensional commuting projector codes admits a nontrivedial logical'string'operator supported by a set of encoded qubits.
the absorption features of the bally ( bal ) quasars in the uv ( observed frame ) are analyzed using lower resolution spectra obtained from the hst archive.   the hires spectra contribute in a number of areas to the analysis. here   we report on : 1. ) bal smoothness, and 2. ) absorption templates. as a by   product of the template generation, the hired spectra provide some information on partial covering. for the c   iv bal in q1246@xmath4047, the observed smoothness of the absorption features rules out a " picket fence " model for the bals because the bal features imply a large number of " clouds " in the bal region if the region is composed of clouds rather than a smooth outflow.. for the h i ly @xmath5 bal, the smoothed bal features rule out a'picket fences'model that assumes that the partial covering is due to turbulent components in velocity space.
abstractrecent investigations have revealed the ubiquitous presence of blueward asymmetries of emission lines formed in the solar corona and transition region ( e.g., @xcite ).   the discovery of these asymmetric line profiles suggests the presence of a highly blue - shifted ( much larger than 20  km  s@xmath0 ) emission component besides the primary emission component, and thus provides a significant challenge to previous results and interpretations which are based on a single gaussian fit.
numerical simulations of star forming molecular clouds have become increasingly popular in the field of molecular gas physics.   many groups have begun to compare simulations of these simulations to observations of the same ( e.g., synthetic observations ). with the improving quality of both simulations and observations,   there is a growing need for a general framework by which the comparisons between observations and simulations can be rigorously assessed. in this paper  , we present a framework that provides several candidate statistical measures for comparing data sets (   ). using this framework, we provide a suite of numerical simulations that exhaustively probe a simple parameter space (  ) and describe how _ linear models _ provide a means to analyze the significance of the statistical measures. using the results of the analysis, we critically evaluate the different proposed statistics in  .
polymer bonded permanent magnets are used in a multitude of applications, ranging from sensors to various electric drive technology.   the magnetic field of the bias magnet can be influenced by the topology and the magnetization direction. for one or more dimensional   sensing of position or rotation in electrical machines and mechanical components, it is important to design a special magnetic field for the target field. in this work,   a simple but accurate topology optimization simulation framework is presented. using the density method ( also known as solid isotropic microstructure with penalization ( simp ) ), which considers the density @xmath5 of the material in each element, which ranges from 0 ( void ) to 1 ( bulk ), we find an optimal topology for a measured magnetic field @xcite. moreover, a special structure for a given target field is presented and physically created.
the relaxation time of the magnetization of a single - domain ferromagnetic particle coupled via exchange interaction is calculated for a pair of atomic spins using langer s approach, which is a general approach to the calculation of the reaction rate of a system with @xmath6 degrees of freedom.   the problem of calculating the relaxation time for a multi - dimensional process is reduced to solving a steady - state fokker - planck equation ( ssfpe ) in the immediate neighborhood of the saddle point that the system crosses as it goes from a metastable state to another state of greater stability. here   we show that this approach fails when the exchange coupling assumes a  critical value " even in the limit of intermediate - to - high damping ( ihd ) because of the inherent assumption that the potential energy in the vicinity of the saddle point may be approximated by its second - order taylor expansion.
ls  i + 61 303 is a be x - ray binary with strong and variable radio emission.   it has been suggested as the potential counterpart of the gamma - ray sources 2cg 135 + 01 and 3eg j0241 + 6103. in this paper   we revisit the hadronic model for high - energy emission in ls  i+61 303 proposed by romero et al. before the magic detection. using an improved accretion model and more sophisticated calculations for the opacity effects inside the binary system  , we show that a hadronic origin for the emission detected by magic can not be ruled out. to test this hypothesis, we consider gamma -ray production in hadronic interactions of relativistic protons from a jet launched close to the compact object and cold protons obtained from the equatorial wind of the be star. at the same time, we investigate the role of @xmath1-ray propagation effects in the formation of the high -energy emission.
spike ( spectrometry processing innovative kernel ) is a new framework for the processing of fourier transform ion cyclotronic resonance ( fticr - ms ) and nuclear magnetic resonance ( nmr ) data - sets.   it is developed as a kernel, extensible to any ft spectroscopies beyond the ones already implemented. in spike,   all the processing in spike relies on a chained syntax in which each element performs an elementary processing task.database url : http://www.spike.org
recent observational evidence @xcite indicates that the universe is presently dominated by an intriguing component dubbed dark energy ( de ).   its gravitational action is to drive the current cosmic acceleration by mimicking a fluid of puzzling negative pressure acting on cosmological scales. in this paper  , we develop a theoretical framework which shows that cosmic acceleration is precisely the observable trace of this violation of the weak equivalence principle ( wep ) coming from the fact that the wep does not apply to the invisible sector of cosmology. using a tensor - scalar theory of anomalous gravity, we show that the observed cosmic acceleration can be accounted for exclusively with this mechanism, without requiring to any explicit negative pressures. as a result, we derive remarkable cosmologic predictions from the analysis of hubble diagrams of far - away supernovae that unveils the nature of the abnormally weighting component and the origin of cosmic acceleration. finally, we use sne ia data to constraint the scalar charges of this model and show an interesting evidence for a new symmetry between the two models.
the yee scheme is one of the most successful numerical methods used in the field of computational electromagnetics, and it is still preferred for many applications because it preserves important structural features of maxwell s equations that other methods fail to capture. among these distinguishing attributes   are that the gauss constraint is exactly conserved in a discrete sense, and electrostatic solutions of the form @xmath2 indeed remain stationary in time. in this paper  , we show that these desirable properties are direct consequences of the variational and discrete differential structure of the yee Scheme, which mirrors the geometry of max well s equations.   moreover, we find that the resulting variational integrators automatically respect discrete differential identities such as the div - curl - grad relations and stokes theorem. using a discrete exterior calculus ( called dec ) as the framework to discretize these differential forms, we also show how to construct other variational methods that, as a result, share these same numerical properties, while at the same time applying to more general domains.
the ground state of the undoped 2-leg heisenberg ladder, a spin liquid with a finite spin gap and exponentially decaying antiferromagnetic spin - spin correlations, is given by the coherent superposition of singlets across the rungs.   addition of one hole leads to the breaking of one of these singlets, in which case the hole gets effectively bound to the unpaired spin, becoming a quasiparticle with spin @xmath9 and charge @x Math10. in this picture   there is no spin - charge separation, a fact that remains valid down to intermediate and weak couplings, as confirmed by various numerical and analytical studies. based on this picture it is possible to construct an effective theory describing the motion and interactions of the hole pairs @xcite. here   we take one step further in that direction by extending the hard - core boson model ( hcb ) description to include the internal structure of the holes. using short - range resonating valence bonds ( rvb )  , we show that the ground state can be though of as a bound state of two quaiparticles, whose characteristic feature is the diagonal frustrating bond across the holes.conclusionst
gamma - ray bursts ( grbs ) are transient events that can be divided into two classes, short - duration and long - duration.   the environments of the grb host galaxies provide important clues for understanding the physical origins of these energetic cosmic events. in this letter  , we present a multi - wavelength analysis of the host galaxy of grb  150101b, which was trigged by the gamma - ray burst alert telescope ( bat ) at 15:23 ut on 01 january 2015. to date, it is the first confirmed active galactic nuclei ( agn ) in known grb hosts ; however, several attempts have been made to identify agns in the grB hosts but yield no results. here, we confirm the presence of a central agn in the star - forming galaxy ofgrb 150105b using data from the very large telescope ( vlt ) and the gran telescopio canarias ( gtc ) with a redshift of 0.134, which is one of the lowest redshifts among sgrb hosts . as a result, we propose that the
the tearing mode is a magnetic reconnection instability in a magnetically confined tokamak plasma.   the neoclassical tearing mode ( ntm ) is expected to be the limiting factor on its operational plasma, and is studied for the first time in three - dimensional toroidal geometry using the gyrokinetic framework of equations. within the resonant layer, the growth rate and frequency of the ntm   are studied by means of the delta-@xmath3 approximation, which is used to study the effects of collisionality and temperature on the stability of the mode. with the introduction of a radial component of the magnetic field, the results show that the mode frequency and growth rate increase with collisionality, and with the variation of the background density, temperature and current profiles. when the magnetic island is smaller than the singular layer width, the nonlinear stabilising effects of the polarisation current slow the growth of the island to an algebraic scaling, while when the island is larger than this size, the linear stabilising effect is more pronounced. at the same time, the modes growth rate increases with collisionivity, and the direction of the polarization current is shifted in the opposite direction from the ion direction
the cooling of a neutron star ( ns ) is strongly affected by the relationship between its internal temperature and its effective surface temperature.   this relationship is determined by equation of state and thermal conductivity of matter in the outer ns envelope. for non - magnetized nss with envelopes composed of iron, this relationship has been thoroughly studied in a classical article of gudmundsson et al. ( 1983, hereafter gpe ). in this article, we reconsider thermal transport in non - magnetsized envelopes of nss and extend the results of the preceding authors in two respects. first, we analyze matter composed not only of iron but also of light elements. as a reference case  , we consider the outermost ns layers composed of fe and the saumon chabrier eos for h and he. second, we implement new, advanced theoretical data on equation of states and thermal conduction of dense matter. specifically, we employ the opacity library ( opal ) radiative opacities for h, he, and c, improved considerably with respect to the los - alamos Opacities used in the previous studies. in these cases, we calculate the @xmath5@xmath0 relationships for
the new x - ray transient galactic black hole candidate xte j1752223 was first detected at the 30 mcrab flux level in the 210 kev range on october 23, 2009 during the galactic bulge monitoring with the proportional counter array ( pca ) of the rossi X - ray timing explorer ( rxte ) @xcite.   the source was found to be in a typical low / hard state ( lhs ) with a power - law with photon index 1.38@xmath40.01 and the power spectrum shows band - limited noise with a total rms of @xmath530 percent, suggesting that it was a typical lhs. since august 3, 2009, the highly sensitive all - sky monitor, monitor of all -sky x - rays image, maxi(@xcite ), has been activated on the exposed facility of the japanese experimental module " kibo " of the international space station ( iss ).    since october 2009, we have observed the brightening of xtej175222123 using the maxi s gas slit camera ( gsc ) during its outburst. in this paper  , we report on
many galaxies are observed with tightly - wound, regular spiral arms covering a significant fraction of their disc.   the most common model of this phenomenon is based on the lin - shu hypothesis of spiral structure, which states that quasi - steady spiral patterns exist in the stellar disc, rotate at a pattern speed, and persist for many orbits. here  , we discuss the formation of single - shock flows in the gaseous disc, and show how the angular offset between these shocks and the minima of the gravitational potential ( the p - arms ) could be used to constrain corotation. using a well known semi - analytical approach, we investigate the resulting gas flow by comparing the results obtained by numerical methods to those obtained by means of semi - analytic techniques. as expected, the response of the gas to the perturbations in the p- and d - arms is strongly influenced by the size of the galaxy, and the effect of the offset function is more pronounced in the case of the d - arm than in the c- and p - arm components. however, the effects of the sf - arm are also important, and they are found to be much stronger than those of the p--arm component.
the quantum - mechanical amplitudes for the scattering of relativistic particles are the subject of a special issue of journal of physics a, which is devoted to the field of quantum chromodynamics.   the paper focuses on the tree - level amplitudes of qcd, the most symmetric non - abelian gauge theory we can study in the laboratory, and the hidden symmetries of its supersymmetric yang - mills theory ( @xmath0 sym ), which has the maximum amount of supersymmetry possible in a gauge theory.
we investigate the emergence of thermodynamics from principles of quantum mechanics in a simple, yet macroscopic system  black - holes.   we show that the hawking temperature of a black hole is given by the rate of change of the entropy of entanglement across the horizon with regard to the system energy. for a relativistic free scalar field propagating in the black - hole background,   the information lost across the horizons is related to black hole entropy and laws of black hole mechanics emerge from entanglements across the Horizon.
the optical conductivity of a single hole in the @xmath1-@xmath2 model in the presence of the lattice degrees of freedom is investigated in the framework of dynamical mean - field theory.   the results show that the incoherent contributions of the model are mainly dominated by local electron - phonon scattering and spin - string excitations within the magnetic polaron, which are well captured by the holstein - hubbard model. at the intermediate coupling region, where the interplay between magnetic and lattice degree of freedom plays a crucial role, the formation of a lattice polaron drives a transfer of spectral weight towards higher frequencies, opening a pseudogap at low frequencies. starting from the polaronic phase, two different mechanisms can be clearly identified as being responsible for the disappearance of the pseudogaps : ( 1 ) reducing the effective exchange energy scale suppresses the positive feedback of magnetism on polaron formation and can lead to a _ closing _ of thepseudogap as the system crosses back to the non - polaron phase.
x - ray and optical observations of active galactic nuclei ( agns ) have been used to probe the evolution of their luminosity function ( lf ) and its evolution with redshift.   this enables us to study the accretion history of supermassive black holes ( smbhs ) which, in turn, set constraints on galaxy evolution. here   we use existing observations of optically selected agn and _ chandra _ deep fields to determine constraints on the redshift 6 shape of both the optical and x - ray lf. using concordance cosmological parameters, we show that the @xmath0 optical lf is constrained by the presence of a very small number of faint sources at the faint end of the qso lf up to ~20 magnitudes fainter than the deepest optical observations. for the x - rays we find that the paucity of sources at these faint fluxes gives the most up - to - date stringent constraints so far on the knee and the faint - end slope of the quantum gravity re - ionization of hydrogen and helium, while the latter can be probed with looser upper limits down to ~30 magnitudes lower than the optical ones.
the diffuse spectrum of ultra - high energy ( uhe ) cosmic rays ( cr ) is expected to consist of a superposition of fluxes from many individual point - sources distributed throughout the universe.   the absence of significant event clustering across the sky sets a lower limit on the local source density or, equivalently, a lower limits on the number of sources that effectively contribute to the spectrum. in this paper   we show that the flux from a few cr sources can significantly fluctuate from a homogeneous distribution that is typically assumed in cr flux predictions using the greisen - zatsepin - kuzmin ( gzk ) region as a model for the composition of cr nuclei. by using an analytic solution to the flux of cr nuclear nuclei derived in refs.1, 2 and 3, we quantify the stochastic fluctuations in the gzKuzmin region of the uhe cr spectrum at @xmath3  ev, which are observed in the hires and auger data with a high statistical significance. due to the strength of the gazk mechanism the spectrum in this region   is dominated by ( and requires the presence of ) local sources  . in contrast to
we compare the relative sensitivities of the cosmic - microwave - background ( cmb ) and large scale structure ( lss ) maps to two different classes of primordial non - gaussianity.   the first model is a multiple - scalar - field model of inflation in which quantum fluctuations in the scalar field responsible for inflation are entirely due to perturbations in the inflaton, and the second model is one that accounts for a small fraction of the primordial adiabatic perturbation from quantum fluctuations occurring in a second scalar fields. both models are general for small deviations from gaussian behavior, but the smallest value for the parameter that can be detected with each of the different approaches is determined by comparing the abundances of high - redshift galaxies as well as the abundance and properties of clusters.
the theory of electromagnetic cascades in matter has been extensively studied in the context of interactions of cosmic rays with the earth s atmosphere, as well as for calculations of performance of detectors of high energy particles ( e.g. @xcite ).   however, it is not clear whether the theory can be applied to some sources of high - energy cosmic radiation, in particular to the " hidden source " scenarios like massive black holes in centers of agn or young pulsars inside the dense shells of recent supernovae explosions. in such objects,   the thickness of the surrounding gas can significantly exceed @xmath11, thus the protons produced in the central source would initiate ( through production of high power @x Math0-rays and electrons ) electromagnetic showers.    we have developed a new model of the @x math0-ray production and absorption processes in relativistic regime, namely when the secondary electrons are directly accelerated by the center of the neutron star or black hole, hit the atmosphere of the normal companion star, and thus produce high energy neutrinos and @x maths0-radiophysics. using the proposed model, we show that the internal@xmath0- ray absorption
the most common computational scheme for evaluating the electronic transport of a molecular device combines scattering theory in the form of the non - equilibrium green s function ( negf ) formalism @xcite with an electronic structure method, the most widely used being density - functional theory ( dft ).   unfortunately for several molecules negf combined with dft appears to disagree with the experimental results. in particular   it seems to systematically overestimate the current flowing across a device, even if one bears in mind the detailed geometry of the junction. in the prototypical case of benzenedithiol ( bdt ) sandwiched between two gold electrodes,   the conductance for the most probable contact geometry calculated with negf and dft is higher than that of _ any _ of the experiments by at least one order of magnitude@xcite. in this work   we demonstrate that most of the errors originating from using local or semi - local exchange and correlation potentials in dft can be corrected by applying an atomic self - interaction correction ( asic)@xmathite scheme to the local functionals, leading to a dramatic improvement of the agreement between the calculated results and those obtained from experiments.
the black scholes framework for the pricing and hedging of derivative claims crucially depends on the assumption of market completeness, i.e.this assumption is not fulfilled if the asset process is driven by more than one source of risk or when market imperfections such as transaction costs are not negligible.   one then speaks of an incomplete market in which investors may attribute different prices to derivatives, according to their risk preferences. here  , we discuss the applicability of the black schole s framework for trading derivatives based on risk aversion and utility - based pricing and hedge strategies.    we show that the framework is not applicable to the case of a jump diffusion process, since it is not possible to eliminate jump and diffusion risk at the same time, and that the investor should try to find an optimal balance between diffusion and jump risk and value the remaining risk in order to obtain a risk premium.
articulated pose estimation from a static image remains a challenge in computer vision.   the difficulty lies in the wide variations in the appearance of object due to articulated deformations, and an effective method generally relies on strong appearance models and expressive spatial models to capture the variations. here  , we propose a novel formulation of pose estimation based on exemplar - based models that captures the interactions between object parts in two aspects : spatial relations between parts at the same granularity level are inferred by deep convolutional neural networks ( dcnns ) ( inspired by  @xcite ), and constrained by exemplar-based models at that level ; spatial relations among parts at different levels follow the parent - child relations in the hierarchy, which are well maintained in the bottom - up inference through exemplars. for each composite part,   exemplars are treated as an object, with exemplars dictating the configuration of its child parts. by doing so, we obtain exemplar / composite part models covering a spectrum of granularity. in addition, we also propose a new formulation that exploits the properties of exemplars to model the spatiotemporal interactions between individual parts. using this formulation, we can infer the spatial relations
the origin of the large - scale structure of the universe involves the assumption that the structure we see today grew by gravitational instability from initial small fluctuations in the density field. in most popular variants of this model,   the initial fluctuations are of a simple form known as a gaussian random field.   one of the reasons for studying fourier phases in depth is the question of possible primordial non - gaussianity of the initial density distribution of the cosmos. here  , we show that the theory of the origin of gravitational clustering is not based on gaussian conditions, but rather on the fact that the phase distributions of different fourier modes are coupled together in a way which has been recently investigated by chiang & coles ( 2000 ) and coles & chiang ( 2000).we find that the results of this study are consistent with the hypothesis that the initial state of the density fields is non - Gaussian, in that the mode coupling effect causes the initial condition to skew when the perturbation is small compared to the mean density. using the cobe dmr sky maps of the cosmic microwave background as an example, we also show that these claims are not supported by the existence of a single - point
the kinetic theory for the freezeout stage of the expanding hadron gas is presented.   the model is designed to describe the chemical freezeout of the color degrees of freedom of hadrons in a dense hadronic matter formed by ultrarelativistic nuclear collision at brookhaven with relativistic heavy - ion collider ( rhic ) and planned at cern with large hadron collidion ( lhc ), which has been studied experimentally by means of very energetic collisions of heavy nuclei such as those currently underway at bro Brookhaven with rhic and are being planned at Cern with lhC. from the data taken from the rhic experiments  , one expects that the system undergoes a phase transition associated with the spontaneous breakdown of the chiral symmetry which is restored temporalily after the collision by the formation of a quark - gluon plasma. as the quarks and gluons of the plasma hadronize, the system would gradually develop a vacuum chiral condensate and the remaining excitaions would expand in the influence of the growing chiralcondensate. this physical picture has been elaborated in terms of a classical equation of motion for the ch
we extend the approach of peres@xcite to consider noisy generalised singlet states in the general case of two subsystems with each subsystem in a @xmath5 dimensional hilbert space.   we find that the number of quantum subsystems over which entanglement occurs is not necessary for the state to be entangled, but that the proportion of the pure ghz - type maximally - entangled states can be increased by increasing the dimension of the subsystems. using the partial transposition condition, we show that the size of the neighbourhood of the maximally mixed state of the ghz type, with noise added, is sufficiently small to give a bound on the maximum value of the parameter @x Math6 for this state to become entangled.
we study a phenomenologically interesting intersecting d - brane model of the monte carlo spacetime ( mssm ) with three generations of quarks and leptons as well as a single pair of higgs fields in type iia fill ( 3 + 1)-dimensional minkowski spacetime.   we show that the model contains a diphoton excess in the cross section near @xmath0  gev, and that this excess can be accomodated by adding additional vector - like states of the sm singlet scalar along with yukawa couplings to the vector -like quark and leptin multiplets. using an integrated luminosity of 2.6@xmath2, we also show that there are sm singlets in the model which have yuk Kawasawa couples to the zeta potentials of the vector- and charge - like quacks and leptic - like particles. while this approach may not allow a first - principles understanding of why the sm gauge groups and associated matter content arises, it may allow a deeper insight into how the finer phenomenological details of the siemens superparamagnetic resonance ( sm ) may emerge.
the helmholtz free energy of a system of polydisperse hard spheres with variable size distribution is studied in the isothermal - isobaric ensemble @xcite.   we study the density dependence of the particle - size distribution and compare the simulation results with an analytical estimate that is obtained by solving the percus - yevick equation for an @xmath0-component hard - sphere mixture@xcite, which works very well at low densities. however, the theory breaks down at a surprisingly low density ( @x Math40.26 ). yet, our simulations indicate that there is  the size distribution that was initially uni - modal, becomes bi -modal when the density is reduced to a given value.    we present a theoretical argument supporting this scenario.
the eruptive stars with peak luminosity between those of novae and supernovae ( e.g., @xcite ) form a heterogenous group with many enigmatic objects, and with no consensus on how to name them.   not only is the name for these objects not in consensus, but also the powering processes of many of them and whether they are due to binary interaction or are formed through single star evolution are debated. here   we review the current knowledge about the powering process of intermediate - luminosity optical transients ( ilots ) whose pre - outburst objects are asymptotic giant branch ( agb ) or extreme - agb ( eagb ) stars, i.e., ngc  300  ot2008 - 1 ( ngc “ 300ot ; @xcites ) and sn  2008s ( sn  8s ; @xmath8 ).
v0332 + 53 is an accreting x - ray pulsar with a spin period of @xmath8 s, orbiting around an early type companion star @xcite in an eccentric orbit of@xmath9 d.   it has been observed that the position of the cyclotron resonant scattering features ( crsf ) changes as a function of the luminosity, implying that the optically thick region where the line is imprinted moves along the accretion columns for as much as some hundred meters. here   we present the results of a detailed analysis of the crsf evolution during the bright outburst of v0 332 + 53 in 2015.    the burst alert telescope ( bat ) on board the swift observatory performed a nearly continuous monitoring in the 15 - 150 kev energy band, while the swift x - rays telescope ( xrt ) covered the soft x -ray band ( 0.6 - 10 kev ) with several pointed observations. using the bat and xrt data reduction, we obtained spectra of the peak energy of the fundamental line at @x Math12 kev, corresponding to a magnetic field of @Xmath12 g. the intensity of the radiation from the accre
nanoparticles ( nps ) have recently been the subject of much attention for their uses in nanomedicine, molecular imaging, and phototherapy.   we have developed a method to functionalize optical fiber tips with semiconductor photonic crystal ( pc ) cavities by using a simple epoxy transfer process @xcite. with this design,   light can be coupled back and forth between the cavities and the optical fibers for efficient optical readout that avoids a bulky free - space setup. furthermore, the optical fiber tip is well suited for remote sensing measurements in tough environments such as the body due to its compact form factor. in this letter  , we show how our fiber photonic crystalline, or fiberpc, can operate as a nanoparticle sensor for both gold and iron oxide and can even quantitatively determine np concentration.
the sloan digital sky survey ( sdss ) is a large photometric and spectroscopic survey of the northern galactic cap.   the sdss has recently discovered a host of previously unknown faint local group members, including @xcite. studying the stellar populations, masses and abundance patterns of these satellites can provide important constraints for galaxy formation and cold dark matter ( cdm ) theory. in this paper  , we adapt the color - magnitude diagram ( cmd ) fitting software match @xcide for use on sdss data, making use of the theoretical isochrones provided by@xcite, and describe several methods of applying this software to the data. using the results of the tests on globular clusters, we show that the proposed algorithms are able to reproduce the observed values of the apparent magnitude of the horizontal branch ( hb ) stars in a population, as well as the magnitude and color of the main sequence turn - off ( msto ), and that the new milky way satellites were formed within the Milky Way ( mw ) halo rather than around the mw. among the new satellite galaxies,   only the number of satellites is significantly lower than the number predicted by cdm theory.
the objective of this work is to propose a two - dimensional cellular automata model consisting of 4 states ( empty site, normal cell, cancer cell or necrotic tumor cell ) to describe avascular tumor growth.   the model is based on a periodic boundary condition, using a moore neighborhood with a radius of 1. at the initial condition ( @xmath1 ),   there is only one cancer cell in the center of the lattice. under the same conditions, the number of cancer cells increases from 0 to 1 and the volume of the tumor decreases from 1.5 to 0.5  cm2.    the effect of therapy is included in order to investigate whether the system evolves to a state of cure after treatment. as a result, the model shows that the tumor growth rate decreases significantly in the presence or absence of treatment, and that the time - spatial pattern of simulated solid tumors is similar to that of real tumors.
elliptic flow, the differential second moment of the azimuthal momentum distribution, has been the subject of increasing interest for partonic systems starting from initial conditions expected at rhic.   the observed high-@xmath4 collective effect depends strongly on the dynamics in a heavy ion collision and provides important information about the density and effective energy loss of partons. here  , we explore the dependence of elliptic flow on the initial density and the elastic cross section of the elastic gluon scattering matrix elements in dense parton systems. using a debye - screened form of lorentz - covariant boltzmann transport theory, we model hadronization, which enables us to compute the final observable hadron flow, and consider realistic nuclear geometry. by applying the parton subdivision technique, we show that the observed fluxes are not due to an increase in the pqcd jet cross section, but to a decrease in the elastic rate of the diffusion of the x - ray scattering matrix into the on - shell phase space. as a result, the observed low-@Xmath4-differential ellipsoverall flux is due to a large number of elastic collisions, which can be
a pattern of chemical reactions frequently encountered in cell biology is one where phosphate groups are attached to a protein by reactions catalysed by one enzyme @xmath2 ( a kinase ) and removed again by reactions catalyzed by another enzyme@xmath3 ( a phosphatase ).   the resulting system is called the mm - ma system ( michaelis - menten via mass action ) and it is the system of principal interest here. in @xcite it was proved using numerical and heuristic approaches that there is bistability in the dual futile cycle of this system. in the present paper   it is proved using bifurcation theory that the number of stationary solutions for any value of the parameters of the system is set to be between three and five, i.e. that there exist more than one stable stationary solution for fixed values of all the parameters. with the help of geometric singular perturbation theory   we show that this is not the case for the full system.    the results are used to obtain a corresponding result for the mapk cascade.
the quantum prisoner s dilemma is a famous two player quantum game which is quantization of the so - called prisoner s dilemmas.   the quantum version involving nonmaximally entangled states is modelled by two qubits, one for each player, and the players have two possible strategies : cooperate ( @xmath0 ) and defect (@xmath1 ). in the present paper  , we present an optical realization of the quantum prisoners dilemma which involves nonmaximal entangled states. to achieve this,   it is necessary to prepare the initial state and perform the strategic operations in the quantum game using quantum optical systems. as a proof of principle, we show that the quantum prison s dilemma can be successfully realized on a nuclear magnetic resonance quantum computer using a quantum optical system.
the character of motion in the 3d potential @xmath3, \ \ \   \end{aligned}\ ] is investigated.   the results are mainly based on the numerical integration of the equations of motion using the hamiltonian to the potential ( 1 ). in the same section,   we give some examples for the reader to understand the usefulness of the@xmath1 spectrum, since it has been used as an indicator to track the sticky orbits and to distinguish between regular and chaotic motion. in sections 2 and 3, we present the analysis of the structure of the poincar phase plane of the 2d system for a set of values of energy. in section 3 and 4, we study the character of orbits in the threed system. in particular, we are interested to find the value of energy, where orbits starting near the exact periodic orbits change their character from regular to chaotic.
this article discusses estimating the effect of a time - varying treatment. as a recurring example, this article focuses on the effects of a medical treatment which is adapted to a patient s state during the course of time.   the main assumption underlying these models is that all information the doctors used to make treatment decisions, and which is predictive of the patient s prognosis with respect to the final outcome, is available for analysis. in order to achieve this assumption,   all of the past treatment- and covariate information which both ( i ) influences a doctor s treatment decisions and ( ii ) is relevant for an outcome of interest has to be recorded. under the assumption of no unmeasured confounding, structural nested models, proposed in @xcite, lok, gill, van der vaart and robins , a sensitivity analysis methodology for estimation of structural nested model effects is developed that does not assume nounmeasured confounders. beyond treatment and covariates  , the data requirements also include the measure of an outcomes of interest ; for example, survival time, time to clinical aids or cd4 count after the treatment
collisionless shocks driven by supernova explosions have been expected to accelerate cosmic rays ( crs ).   the acceleration mechanism is though to be diffusive shock acceleration ( dsa ), but recent observations show that supernova remnants ( snr ) accelerate crs @xcite. in this paper, we perform two - dimensional hybrid simulations of collisionless shocks propagating into partially ionized plasmas for @xmath10, that are higher alfvn mach number and slower shock velocity than that of the first simulation. using a two -dimensional hybrid code that computes the motion of protons and hydrogen atoms, maxwell s equations in the low - frequency limit, and ionization of hydrogen atoms@xcite, we show that the shock strongly amplifies the magnetic fields in the downstream region of the snr plasma. because the ionization timescale is much longer than the gyro period for typical young snrs, we adopt cross sections boosted by a factor of @x math12, but ionization time scales are still too long for current supercomputers.
young neutron stars ( nss ) are among the most extreme physical environments in the universe.   they are born hot, but cool rapidly due to neutrino production in their interiors ; however, details of the interior structure of such stars remain poorly understood owing to our incomplete understanding of the strong interaction at ultrahigh densities and the uncertain cooling rate. here   i describe the basic properties of young nss and their nebulae, and summarize recent observational work that has begun a revolution in our understanding of how these stars work.
we recently developed a theory for the relaxation dynamics of adsorbate vibrational modes whose frequency lies within the long - wavelength acoustic part of the substrate phonon spectrum.   we have shown that the relaxation of these modes is governed by resonant coupling to bulk substrate phonons, and that the vibrating overlayer radiates its energy into resonant acoustic waves. in this paper  , we explore the use of superlattices to achieve this goal. using a model system corresponding to an ordered adsorbed overlayer on a face - centered cubic ( fcc )superlattice, we show that the mass modulation of the superlattenice causes frequency gaps to open in the bulk phonon spectra for modes propagating parallel to the stacking direction, @xmath2, for modes traveling in the van hove singularities. at the gap edges,   the modes expelled from the band - gap regions gather near van hoves singularities with respect to the substrate normal. as a result, the lifetime of frustrated translations ( ft ) and rotations can be dramatically altered by modifying the composition of the substrates.
we propose a mechanism of dynamical mass generation by exciton condensation and exchange - driven polarization to qualitatively describe the abelian and the nonabelian fractional quantum hall effects ( qhe ) in graphene.   we extend the composite fermion chern - simons ( cs ) theory @xcite to the case of dirac particles attached to an even number of flux quanta through the cs gauge field, which can be implemented by a unitary transformation. using the cs transformation, we show that the ground state of the relativistic composite dirac fermions ( cdf ) is defined by the charge neutral state with all negative energy states filled. at the filling fractions   with an even integer, we will show that it is energetically favorable for the cdf to develop an excitation with a cdf mass gap at low density above the condensate.    the latter supports single quasiparticle excitations with a high density at the low density ; the exciton mass gaps have the same sign for all su(4 ) components, indicating that the su(3 ) symmetry is unbroken. on the other hand,   the x - ray absorption spectra of
we calculate the fermion propagator in flrw spacetimes with constant deceleration.   the propagator is derived from the friedmann - lematre - robertson - walker ( flew ) equation and the one loop effective action induced by fermions using our propagator. for the massive case,   we find the following : ( 1 ) a scalar field for which we can achieve @xmath11 in several cases to which we will turn shortly ; ( 2 ) a non - symmetric graviton field for whom we can obtain @x Math11 in the current case ; ( 3 ) a minimally coupled massless scalar fields for which you can achieve@xmath10 in the present case ; and ( 4 ) a free, quadratic fermium field for where you can get @x math11 in this case.
quantum chromodynamics is a perturbative field theory for quantum chromodynamics, corresponding to energies above @xmath11 mev.   the difficulty is that when computing a quantity with more than one scale, large logarithms of ratios of those scales appear which invalidate the naive perturbation expansion. in this paper  , we show how to resummed and match the distributions of event shapes using soft - collinear effective theory ( scet ) techniques. at the threshold region near the center - of - mass energy near@xmath22 large logars of the form @x Math23 appear at fixed order in perturbated theory. by resumming these terms,   they can be ( re)summed at once, and the results are then combined with fixed order results.
we study the equilibrium properties of a mixture of condensed bosons and spin - polarized fermions through the dimensional crossover from three to two dimensions, by following the procedure outlined by roth @xcite for the three - dimensional ( 3d ) mixture.   we neglect bf interactions and we include bf @xmath0-wave interaction self - consistently in a suitably modified gross - pitaevskii ( gp ) equation for the bosons. for the case of bf repulsive interactions,   the increasing anisotropy softens the repulsion, and a quasi-3d spatially demixed mixture is mixed in quasi-2d.the results depend on the model one assumes for the bi - dimensional scattering lengths. in the strictly 2d regime  , the stability of the mixture depends only on the scattering length and the transverse width of the cloud ; in the true 3d regime, the effects of the geometry induced by the trap deformation are negligible.
item recommendation predicts a personalized ranking over a set of items for individual user and hence alleviates the " information overload " dilemma.   item reviews are a diverse and complementary data source for recommendation beyond the user - item co - rating information. in this paper   we propose two novel models to integrate item reviews into matrix factorization based bayesian personalized ranking ( bpr - mf ). like hft  , they integrated item reviews and unlike hft they generate a ranked list of items by leveraging the information from item reviews. in each of the two models, we make use of text features extracted from item Reviews using word embeddings. and on top of text feature extraction, we uncover the review dimensions that explain the variation in users feedback. one model treats the review factor space independent of the latent factor space ; another connects implicit feedback and item reviews through the shared item space.    we empirically evaluate the proposed models on multiple real - world datasets which contains over millions of feedback in total. with the help of item reviews,   the experimental results show the benefit of leveraging item reviews on personalized ranking prediction.graphical abstract
noise modeling has an important role in the bayesian inference setup to achieve better robustness and accuracy.   typically noise is considered to be additive and dense ( possibly even white ) in nature. in this paper   we investigate the effect of sparse noise modeling in a standard Bayesian inference tool called the _ relevance vector machine _ ( rvm ). for a bayesian linear model setup used for regression,   the standard rvm uses a multivariate isotropic gaussian prior to model the additive dense noise. here  , we develop a rvm for such a combined ( joint ) sparse and dense noise scenario by treating @xmath12 as a combined noise. by learning parameters of@xmath9 and @x math12   are used iteratively to estimate @x Math9 without the need of estimating @xMath10.    we also consider the scenario where the signal @x maths9 and noise @x mathematics10 are block sparse. by using techniques similar to the ones in the existing rvm, we generalize the methods to signals with unknown block structure. by applying the new rvm to the case of block sparse signals, we derive update equations that can be used iter
the cooling flow model of galaxy clusters is based on the assumption that hot gas in the dense centers of rich clusters will cool radiatively in less than a hubble time.   however, the large quantities of cool gas expected to accumulate from the cooling flow have rarely been detected. here   we show that the mass deposition rates of the cooled gas are much lower than previously thought and that some of the excess emission associated with cooling flows can be attributed to x - ray sources other than thermal bremsstrahlung or line emission from the thermally radiating medium ( icm ). using a combination of high - resolution spectroscopic and theoretical calculations, we find that the observed mass deposition rate of cooling flow gas is about one order of magnitude smaller than the mass deposit rate predicted by the standard cooling flow models. as a result  , it is now possible to estimate the mass of the cool gas at the center of many clusters by assuming that it is actually cooling more slowly than the heating process suggested by the model.
the long - term pre - flare evolution of the photospheric magnetic field and the sunspot structure, and their correlation with the pre - eruption dynamics in the upper layers of the solar atmosphere, were investigated for the x1.8 flare on 2011 september 7.   the atmospheric imaging assembly data at passbands of 304  ( heii, t@xmath20.0 ) and 531  ( t@Xmath20% ) were used to analyze the changes of the transverse photospherical magnetic field ( @xmath0 ) around the flaring polarity inversion line ( pil ) and the white - light ( wl ) intensities in the surrounding peripheral penumbral region. during the period of apparent sunspot rotation,   both horizontal field strength and the inclination angle of the vector magnetic field declined gradually.    the wl intensities of the coronal mass ejections ( cmes ) from the same ar as the previous x2.1 event also decreased gradually over the course of the 6-hour long pre - flares. however, the values of the radial outward stretching of the peripheral magnetic field increased rapidly during the early stages of the flare - cme eruption.
we study the quantum dynamics of a three - level ladder - type atomic system possessing orthogonal transition dipoles and embedded in an optical leaking resonator.   the atomic sample is pumped coherently and resonantly with external electromagnetic field sources. despite of photon scattering into surrounding electromagnetic modes including the cavity one and resonant laser - atom driving, we identify regimes when the cavity mode is empty in the good - cavity limit which are distinct from interference phenomena observed in @xcite where the experiment was performed in the bad - cavity range and different parameter regimes. here   we show that the cavity frequency in resonance with particular resonance fluorescence sidebands leads to destructive quantum interference effects among the involved transition pathways. for a single level atom,   these effects are mediated by the decay rates of the corresponding transition dipole frequencies and the cavity - atom interaction constants as well as by quenching of spontaneous emission due to interference effects induced by quantum interference between the decaying pathways. at the same time, most upper bare - state population inversion is achieved as well in our system although it is identified with coherent population trapping effects rather than quantum interference phenomena which lead to zero cavity mean - photon numbers.
the blandford - znajek ( bz ) mechanism has been used as a central engine for powering gamma - ray bursts ( grbs ), where rotating energy of a stellar black hole ( bh ) with magnetic field of @xmath0 is extracted along the magnetic field lines supported by a magnetized accretion disk.   recently much attention has been paid to the magnetic coupling ( mc ) process, where energy and angular momentum are transferred from a fast - rotating bh to its surrounding disk by virtue of the closed field lines connecting them. in this paper   we propose a new scenario for extracting rotational energy of the disk matter by considering the configuration of the magnetic fields restricted by the screw instability. using another equivalent circuit we derive the expressions for the powers and torques of the bz and mc processes, and compare these powers with the variation of the two parameters, i.e., the bh spin and the power - law index of themagnetic field on the disk. it turns out that the dl process is generally less efficient than the other two mechanisms, and it is comparable with the latter two when the b h spin approaches unity. under some assumptions on the unknown astrophysical
horava - lifshitz gravity ( hlg ) is a new approach for the quantum gravity with an anisotropic scaling in ultraviolet ( uv ).   this approach is based on the renormalization of the theory of general relativity ( gr ) as quantum field theory ( qft ) for the uv metric field, where the dynamical critical exponent ( @xmath3 ) makes the theory non - relativistic. by introducing higher terms of the scalar curvature,   the perturbative nonrenormalizability of the gr is cured. however, this introduces an additional problem, for instance, to the uniqueness of the model @xcite. from a minimal approach that will be elaborated below, which assures perturbatively renormalizable uv completion of gr as qft, one looses some properties of gr and creates additional degrees - of - freedom. at the same time, the scale factor in cosmological radiation, matter, de sitter  , chaplygin gas and quantum chromodynamical equations of state ( eos ) is compared between the scales factor in general relativity, quantum chromodynamics and quantum gravity. using the results and discussion of the present paper,
the number of muons produced in simulated air showers is a sensitive indicator of the primary composition of the cosmic ray collisions.   we use air shower universality features to predict the surface detector signal expected for auger cherenkov tanks from the electromagnetic and muonic shower components at 1000 m from the shower core. using the universality of the electromagnetic contribution to the signal measured by the auger surface detectors, @xmath1, we are able to determine an energy scale independent of the fluorescence energy measurement. this allows for a direct test of the predictions of hadronic interaction models.
abstractin this letter we present the results of recent observations of the perseus cluster performed with the major atmospheric gamma imaging cherenkov ( magic ) telescopes and the detection of ic  310 ( atel  # 2510 ), a head - tail radio galaxy in the medium energy range.   the redshift z=0.019 is corresponding to @xmath8 1mpc from the cluster s central galaxy, ngc  1275 ; it is located in the field of view at the angular distance of@xmath20 and the central agn of the cluster at @x Math9 on the right side of the x - ray spectra. for the first time  , we show that the emission of an extragalactic very high energy ( vhe ) blazar, @xcite, can be detected by both the magic  i telescope and the lat instrument on board the _ fermi _ satellite.
we study the continuous - variable ( cv ) analogue of the deutsch - jozsa ( dj ) algorithm, which is an early example of a discrete - variable quantum algorithm that has been important in demonstrations of quantum speed - ups.   we introduce a particular model for the computation of the dj problem in a cv setting and show that the cv dj algorithm is necessarily probabilistic and its performance must therefore be compared to the classical case where bounded error is tolerated. within the constraints of this model  , we show that our cv Dj algorithm s performance against the classical deterministic case is significantly better than that of the classical one because it does not require the target qubit.
the properties of elliptical galaxies are not easy to study since we can measure only their integrated properties which contain information on several stellar populations of stars with different ages and metallicity.   detailed models of chemical evolution and population synthesis are therefore necessary to solve this degeneracy. here   we discuss a model of the chemical evolution of ellipticals which is based on the supernovae ( sne)-driven galactic wind model. in this model  , efficient star formation leads to the development of a galactic wind, once the thermal energy of the gas, due to the energy injection from sne and stellar winds, is equal or larger than the binding energy ofThe galaxy evolves passively after the occurrence of the galactic wind and the only active process is the restoration of gas from the stars into the interstellar medium ( ism ). during this stage   there is a clear overabundance of @xmath1-elements relative to iron in the icm, since they are the major contributors to the enrichment of the ism. as a consequence,   the galaxy has a high mass to luminosity ratio ( m / f ) and a low metallivity indeces of fe and mg, indicating that it has undergone a
we explore an analogy of quantum information processing, based on classical ( optical ) waves.   this approach is inspired by the observation that some of the essential properties of quantum knowledge are in fact wave properties, where the wave need not be a quantum wave. by exploring the limits to where the classical analogy can be pushed  , we aim to obtain information about the subtle but profound differences between the quantum system and the classical wave system. in addition, the classical systems may serve as model systems for the corresponding quantum systems, e.g. elucidating the mathematical structure of a problem.
the detection of supernova ( sn ) neutrinos in dark matter ( dm ) detectors using various detector materials is an attractive possibility.   the present paper uses the results from the basel / darmstadt simulations of the coherent elastic neutrino - nucleus scattering ( cenns ) process on @xcite to study the detectability of sn neutrines in dm detectors employing various different detector materials, and also study the possibility of demarcating the different phases of the neutrine emission from the sn using the same detector material. for each detector material,   a total of about 100 events per @xmath1 of detector material are expected to be emitted during the neutronization burst phase, the accretion phase and the cooling phase, which can be measured by measuring the total sn neut rino light curve. since the cenn s process is flavor blind, the proposed method will be complementary to the oscillated@xmath4, @x Math5 flavors detected by other detectors through charged current ( cc ) interactions.
in his 1939 paper  @xcite, wigner considered the subgroups of the lorentz group whose transformations leave the four - momentum of a given particle invariant.   these subgroups are called wignar s little groups and dictate the internal space - time symmetries in the Lorentz - covariant world. in this report  , we introduce wigners little groups for massive and massless particles. among them, three of them generate the rotation subgroup which is locally isomorphic to the group e(2 ) or the two - dimensional euclidean group. however, it is also possible to construct the cylindrical group with one rotational degree of freedom and two degrees freedom both leading to up - down translational degrees freedom that correspond to one gaugedegree of freedom for the massless particle.    in addition, we show that the polarization of massless neutrinos is a consequence of gauge invariance.
a general scaled hamiltonian is derived which nicely describes the transition from soft to hard interactions for three soft interacting particles on a ring with point - like interactions and also shows that the dynamics occurs inside a soft triangle billiard.   the dynamics depends only on the _ masses ratio _ between particles and  softness ratio  of the interaction. in the case of two particles with unequal masses,   both the mass and softness ratios are equal to 0.1 and 0.2, respectively.    the hamiltonians are then applied to the toda model where the particles interact with each other on a frictionless ring with different degrees of freedom and the collisions are at different points in the ring. using this model, we show that the equilibrium motion of all three particles on the ring is equivalent to the motion of one particle moving freely inside the triangular billiard which hard walls. in order to study continuously the transition between soft and hard walls, equations of motion must be well defined in all cases.
the photometric variability of the eclipsing binary star lv  her ( tyc  2076 - 1042 - 1 ; @xmath9, @x Math10, j2000.0 ; spt f9,@xmath11 ) has been determined by using high - quality photometric and spectroscopic observations.   the variable star was observed by ursa on 156 nights during parts of nine observing seasons from 2001 february 18 to 2009 april 8. in   we determine the absolute dimensions of the system, and compare these with models of stellar structure and stellar evolution.
the tunnelling of a dilute bose - einstein condensate in a double - well potential @xcite provides an atomic physics analogue of a josephson junction array.   however, the experimental observation of the transition between the dc and ac effects is challenging because the small energy splitting associated with josephalic oscillations means that thermal or quantum fluctuations will tend to destroy the effect even at the lowest achievable temperatures. in this paper  , we show that in the regime of most interest for experiments where the energy splittings are large, the influence of higher - lying states can not be ignored. by considering the time - dependent evolution of the barrier as the barrier is moved, we analyse the transition from dc to ac tunnelled in terms of transitions between eigenstates.
the european parliament and the council of 25 november 2009 on the taking - up and pursuit of the business of insurance and reinsurance ( solvency ii ) introduce new capital regimes on insurance companies.   the new capital requirements for insurance companies are described in the following sections :   section 4, article 101, p. 3:   the capital requirement shall cover at least the following risks :   existing business, as well as the new business expected to be written over the following 12 months ; with respect to existing business, it shall correspond to the value - at - risk of the basic own funds of an insurance or reinsurance undertaking subject to a confidence level of 99,5 % over a one - year period ; the solvenccy capital requirement should be calibrated so that all quantifiable risks to which an Insurance or Reinsurance undertaking is exposed are taken into account ; and the coverage of existing business and new business should be balanced against the risk of unexpected losses.
the mass and radius of several neutron stars in low - mass x - ray binaries ( lmxbs ) have been inferred by combining measurements of the blackbody normalisation, eddington luminosity, and distance from the burst.   these quantities are challenging to measure alone, but particularly substantial systematic errors are known to affect the black body normalisation. here   we investigate the intrinsic reproducability of burst normalisation measurements using a uniform, homogeneous sample of bursts from the low - masses gs  1826@xmath024  and ks  1731@x Math026, from the _ rossi x -ray timing explorer_ ( _ rxte _ ) proportional counter array ( pca ) on the american space observatory s mission to the vicinity of the ecliptic plane.. we find that the observed variation in the measured blackbody temperature varies by a factor of @xmath2 at burst luminosities well below the eddinton limit, and by a further factor of ~1.5 at burst lumosities above this limit. for the same burst,   the apparent radii measured from two bursts vary by an order of magnitude more than the
vitruv is a general purpose spectro - imager for the prima enabled vlti.   the instrument is described in detail in these proceedings by malbet et al. ( 2005 ) and we concentrate on a few key areas where vitruv spectro-imaging will make a significant step forward : 1 ) interferometric imaging of compact sources with a quality similar to the plateau de bure observatory ( pdbi ) with amber and the ats ; 2 ) massive surveys of sizes ; 3 ) line emission imaging of stellar surface and line emission kinematics.
screening in semiconductor nanocrystals is a fundamental issue, the importance of which is mostly due to the large amount of technological applications inherent in the world of nanostructures.   while screening in bulk semiconductors is a well known and widely investigated subject, @xcite, the phenomenon of screening in nanostructure is still not fully understood. in the present paper,   a first - principles study of shallow impurity screening in si and ge nanocry crystals is described.. the charge density induced by donors and acceptors in si ( ge ) and ge nanoparticles is discussed, pointing to the connections to both the point - charge case and the bulk limit. just like in bulk silicon,@xcite the response to isocoric impurities in nanocrystal is similar to that of a point - charged state. at the same time, a description of the local field effects on the induced charge is given showing that the present real - space analysis gives a way to distinguish between surface and bond polarization contributions. in order to better appreciate the merits and the shortcomings of the thomas - fermi theory, an alternative derivation of the model from the hohenberg and kohn theorem @
we consider the simplest neutrino mass generation scheme based on an effective seesaw mechanism with explicit described by the complex triplet, given as @xmath11.   we derive the necessary and sufficient conditions for the potential to be bounded from below using the standard model ( sm ) of the type - ii seesaw model. in order to ensure that a set of values for the quartic couplings corresponds to a stable vacuum, we find that the vacuum expectation value of the triplet is proportional to the strength of the lepton number violating coupling between the left - handed leptons, which is the only leptonNumber violating coupling in the model. under these conditions,   the potential is stable up to some given scale.
geometric phase in an auxiliary qubit coupled to a quantum many - body system is studied.   two kinds of coupling between the auxiliary qubits and the many - bodies are considered : the first kind of coupling corresponds to dephasing in the qubit, while the second one results in energy loss ( dissipation ) of the qu bit.    we show that the off - diagonal elements of the reduced density matrix change drastically in the vicinity of critical points for both types of coupling. by applying a general formulism to the case where the coupling conserves the energy of the Qubit,   it is shown that the reduction of the reducing density matrix can be used to signal the critical points of the quantum system.
cognitive research deals with how people learn and solve problems.   the cognitive revolution began in the 1970s when miller s magic numbers 7@xmath02 ( 5 to 9 ) were used to measure the limits of the working memory or short term memory ( stm ), i.e., how much information can be stored in stm at one time. since then, there has been a growing body of research that has shown that people can extend the limit of their working memory by organizing disparate bits of information into chunks or patterns. using chunks, stm can evoke from long term memory, highly complex information. for example, experts in a field such as chess and physics have large chunks of  compiled " knowledge in ltm and several pieces of knowledge can be accessed together as a chunk  @xcite. for an expert in physics, vector addition, vector subtraction, displacement, velocity, speed, acceleration, force etc. can not be accessed as one chunk while solving problems while they are being presented with a very good chess board that corresponds to the game of a world - class chess player because they are able to chunk the information on the board and remember the position of one piece with respect to another
we present some distributions of muon physical variables obtained by use of pythia event generator.   the parameters were set to those values that allow fast simulation for the antiproton beam with the energy @xmath7=14 gev, which corresponds to the center of mass frame energy of@xmath8 collision. in the case of initial state radiation ( isr ) and final one ( fsr ) the muons produced in the corresponding hard qcd ( qcd - qcd ) @x Math10 subprocess would be called in what follows as the " signal" ones, while those which will appear in event due to meson decays would be referred to as " decay" muons. from the results we can estimate the size of the corrections needed to reconstruct the original input parton distributions.
the leavitt law ( ll ) is a linear relation between the pulsation period and magnitudes of @xmath2 cepheids, in the sense of that the brightest cep heids have longer periods.   this relation is a cornerstone in the measurement of the extragalactic distances using stellar standard candles. however, in order to obtain an accurate calibration of this relation, it is important to establish the effects of non - linearities, metallicity and companions on it, as it is mentioned by @xcite ; as well as other effects such as cepheid light curves showing the hertzsprung progression and cephids exhibiting changes in period. here  , we present a brief literature review of these issues.
summarythe radial velocities of the six dwarf spheroidal ( dsph ) companions to the andromeda ( m31 ) galaxy have been measured using the spectrographs on the _ keck telescopes.   the data are used to estimate the total mass of the extended halo of m31 by 50 per cent, which is the most reliable estimate of the mass of any member of the local group to date.
in this article we revisit the notion of _ state  in quantum formalism, and show that it is not only a unit ray in an hilbert space, but also a quantum observable.   we discuss the way a state is transformed through the action of an operator named  quantum observable , and the way it evolves with the introduction in the formalism of an evolution parameter, i.e. a time parameter. here, our approach is minimalist in the sense that our departure point is the two - dimensional euclidean plane on the real numbers, denoted @xmath5, so familiar to us since the kindergarden - grade 12.
the first principles calculations of the si(335)-au surface have been performed using the siesta code @xcite-@xcite, which performs standard pseudopotential density functional calculations using a linear combination of numerical atomic orbitals as a basis set.   the calculations have been carried out using the generalized gradient approximation to dft, troullier - martins norm - conserving pseudopotentials, and a double-@xmath4 polarized ( dzp ) basis set for all the atomic species in the supercell. at the fermi level, the system has been modeled by slabs containing up to five gold atoms running parallel to the step edge, i.e. in the @xmath1 $ ] direction.  also, the electronic properties of the system have been investigated using the angle - resolved photoemission spectroscopy ( arpes ) experiments. among the results,   it has been found that the model of this surface, based on an analogy with si(557)-au surfaces, is not consistent with the experimental data. however, the structural model of the surface has been confirmed by first principles simulations.
string duality is a recently discovered symmetry of string theory.   it is not manifest in the weak - coupling perturbation expansion by which the theory is usually studied, but it is a property of the exact theory. as a result, string duality gives information about the behavior of string theories at strong coupling. in this colloquium   i will try to explain these developments and to put them in the context of the search for the unified theory of particle physics and gravity.
the present universe is highly inhomogeneous on small scales ; the density contrast is of the order of @xmath3 in the solar system,@xmath4 on galactic scales, and of the Order of unity even on the scale of superclusters.   we have to go beyond the friedmann - lematre ( fl ) universe model in considering such systems. for a long time we have regarded that a fl model is a large - scale " average " of a locally inhomogenous universe ( averaging hypothesis ). even though the observational data are consistent with the picture that our universe is described well by a robertson - walker metric, we are not sure how to derive the background fl model from the inhomogeneity universe by any averaging procedure, or how the back reaction of the small - scale inhomogeneities affect the global dynamics when averaged on larger scales.in this review, we discuss the effect of inhomogenies on the cosmological parameters of the current standard big bang model.
the radio emission of core - dominated, radio - loud active galactic nuclei ( agn ) is generated by synchrotron radiation generated in the relativistic jets that emerge from the nucleus of the galaxy, presumably along the rotational axis of a central supermassive black hole.   very long baseline interferometry ( vlbi ) is a powerful tool for probing the compact radio emissions of such agn with high resolution using very long antenna - based multi - frequency data. to achieve the highest - quality images possible for the radio - telescope array used,   the complex gains of the observed and measured visibility functions on the baseline between antennas must be determined and removed from the data, and the signals obtained at different antennas can be accurately synchronised during correlation. here  , we present a new method for comparing multi - frequencies self - calibrated vl bi images of agn via phase self - calibration, which essentially places the centre of gravity of the radio brightness distribution at the phase centre, which has coordinates @xmath13. the standard theory of extramolecular dynamics ( e.g., quantum mechanics ) of the universe is used to explain the observed spectra of the core region of the ag
a new effective string gravity model for the last stages of primordial black hole ( pbh ) evaporation @xcite is proposed.   it is based on the action expansion in scalar curvature corrections of the gauss - bonnet term @xmath0, which is invariant at the level of second order and is taken into account by the perturbational approach of string theory. using a dedicated code, a bh type solution with a regular horizon of quasi - schwarzschild type and asymptotic behaviour near this horizon   is obtained. under time perturbations at the singularity, the minimal bh mass has the order of planck one ( more precisely planck masses@xcite ) and the hawkingevaporation law is established. from this law, we show that the direct experimental registration of pbh relics as dark matter candidates is impossible.
we have measured radial velocities of galaxies in the field of apm clusters using an observational program.   we have used this data to estimate cluster velocity dispersions for 17 apm clustering clusters ( 13 of these without previous estimates ) with a search radius of 0.75 mpc and a redshift of between 0.06 and 0.13 h@xmath3. by combining the new velocity dispersion estimates with those from the literature providing correlations between @xmath1 and richness counts, we have found that the distributions of cluster velocity disperseions are more representative of the true distribution than previously reported.
we investigate the degree to which radiative feedback can suppress the formation of low - mass galaxies that form in dark matter halos with virial temperatures @xmath1 ( below which atomic cooling is inefficient ).   we use analytic models for the expansion of galactic outflows described in @xcite, which self - consistently include the impact of ram - pressure stripping of halos and metal enrichment. using a simple parametrisation of the degree of photoionization suppression by choosing a step - like reionization and using a suppression criterion taken from dhrw  , we find that the majority of galaxy formation is suppressed when halos ionized before turnaround, with a mass below a certain threshold, fail to cool a ` sufficient'quantity of gas in order to form a galaxy.
the ring - imaging erenkov counter ( rich ) at the electron - proton collider hera at desy in hamburg, germany is a highly selective multi - level trigger system for the measurement of neutral @xmath0 mesons produced in proton - nucleus interactions.   it is sensitive to events with large hit multiplicities, e.g. those caused by a superposition of multiple interactions in a single bunch crossing of the hera proton beam. since the first level trigger ( flt ) is a modular message - driven system, the message load in its network increases with the hit multiplicity which may introduce dead - time in the system. to protect the flt from processing multi - interaction events, a multiplicity veto   is needed. here   we show that the rich detector can be used as a platform for the development of a multifaceted multiplicity vetoed system. using the veto system,   the number of photons generated by charged particles in the rich can be reduced by blocking the transmission of messages with high hit multipliities. this veto mechanism is based on the fact that the number and size of the dark areas of the rich detectors are highly correlated
we consider a pseudo - spin 1/2 boson system confined in a harmonic trap with a weak weyl type three - dimensional ( 3d ) spin - orbit ( so ) coupling @xmath1.   we investigate the role of two - body interaction in determining the ground state density and spin texture of the system. by numerically minimizing the gross - pitaevskii ( gp ) energy functional for the model with respect to the variational parameters, we find two distinct ground state phases, namely the plane wave and standing wave(or stripe ) phases, which are degenerate in the absence of harmonic trap. when the intraspecies 2-body interaction is larger or smaller than interspecies interaction, these two phases are found to be stabilized in the presence of strong so coupling regime.
the thermalization mechanism that leads to the formation of a quark - gluon plasma ( qgp ) in relativistic heavy - ion collision experiments is still poorly understood.   it has been suggested that quantum chromodynamics ( qcd ) perturbation theory, no matter at which order one truncates it, may be unable to describe thermalization at all. here   we show that the qcd framework known as the color glass condensate ( cgc ) can be used to estimate the thermalization time scale for the qgp in the regime of large occupation numbers and that the initial condition for the classical fields is independent of the space - time rapidity variable, and the equations of motion maintain @xmath12-independence during the time evolution. by taking into account the non - linearities of the yang - mills equation of motion for the two - source problem, we find that the thermodynamic parameters of the cgc are well suited for the early time dynamics before thermalization.
the hercules - aquila cloud is a new overdensity of stars found in the sloan digital sky survey ( sdss ) dr5 data.   it is a bifurcated and cleanly differentiated stream that crosses the direction of virgo   @xcite, whilst the tip of the herculean cloud is just visible. here  , we describe the structure and its relationship to the other two structures, the sagittarius stream and the virgo overdensity, as well as the underdensity of ursa major  @xcite.
divalent rare earth hexaborides, eub@xmath0 and ybb@x Math0, have been at the focus of attention for the last couple of years because of their anomalous electronic and magnetic properties.   the intriguing magnetic and transport properties of these compounds arise from the complex electronic properties which are attributed to the half and full filled @xmath1 orbital of eu and yb respectively. in this paper   we perform a band structure calculation based on weighted density approximation ( lda ) and gw approximations@xcite for both the valence and conduction bands of eub#@x math0 using a combination of self - interaction and on - site coulomb interaction among the local 4@x maths1 electrons. with the introduction of chemical pressure by substituting ca for eu in eub*@xMath0, the ferromagnetic transition temperature is lowered to 5.5 k. the results obtained from the calculations are compared with the experimental data and show that the effective mass of the itinerant charge carriers decreases as the temperature increases.
we investigate the effect of a periodic potential on the magneto - conductivity of graphene layer.   we find that the electrical modulation of the layer by the potential introduces a new length scale and a new energy scale into the problem, and that it also leads to weiss oscillations in the transverse magnetic field which are even more pronounced than in typically two - dimensional ( 2d ) electron gases with a parabolic electron spectrum.
the persistence of a stochastic variable fluctuating in space and time is a well - known property of spatially extended nonequilibrium systems.   we reinterpret this property in the context of the @xmath2-state potts model, which has two distinct but equivalent ordered phases : the random walkers and the persistent potts sites. for each phase,   the persistence probability at time @x Math7 is defined as the fraction of sites in which the field @x math11 did not change its value in the time interval @x maths18 $ ]. to study the spatial correlations between persistent and nonpersistent sites in such systems, we consider the diffusion dynamics of a system with a nonequ equilibrium field@xmath11, which takes discrete values at each lattice site, and then evolves in time through interactions with its neighbours. by taking into account the initial walker density, we show that the coarsening length scale, set by the mean distance between walkers, is the relevant length scale for all spatial correlations in the first phase of the polynomial distribution of the persistence exponent, where the number of persistent sites decreases with time. on the other hand, the separation length scale
the structural analysis of dynamic lumped process models is an important step in the model building procedure @xcite, and it is used for the determination of the solvability properties of the model.   high - index differential - algebraic equations ( dae ) systems need prolongation to reveal all the system s constraints, and to determine consistent initial conditions. in the present work,   pryce developed a taylor series method based on his structural analysis method@xcite and on pantelides work in @xxcite. using this method, we find all the constraints for a large class of ode using only prolongation, which can be considered as fast prolongation method. in particular, we consider pryce s method and the symbolic differential elimination package rifsimp in maple for finding the index of the system, its number of degrees of freedom, and exactly which components should be given initial values.
we use dynamical and geometric distortions to study the large scale coherent infall of galaxies, from a sample of @xmath16 lyman - break galaxies.   the results show that the clustering signal measured in real - space is smeared along the line - of - sight by a coherent infall caused by gravitational instabilities at large scales, which is quantified by measuring the amplitude of the two - dimensional correlation function between the observed redshifts of the galaxies and the measured comoving distances, measured in _ redshift - space _ ( @x Math1-space ).. the constraining constraints on cosmology can be obtained from the fitting of the @x math1-sphere distortions.
the effects of foreign inclusions in an ordered medium can be described by virtual defects within the foreign inclusion itself.   we report observations of freely suspended inclusions with fixed boundary conditions in smectic - c films, and we develop a theory for their energetics. at sufficiently high density,   the inclusions form circular structures called islands, where the film contains an integral number of additionalsmectic layers. under normal boundary conditions, these inclusions have a preferred orientation relative to the tangent vector to the boundary separating the two phases, which we call the @xmath1-director. when introduced into a freely suspended monolayer or nematic emulsion, the director is distorted by the presence of droplets of nematic liquid crystal in an isotropic host, and the droplets themselves carry a topological hedgehog charge which must be compensated for by creating additional defect structures within the ordered medium. in this paper  , we show that the shape of the inclusion can be controlled by changing the direction of the droplet - defect pair, and that the distortion can be explained by the existence of a new dipole - like structure in the outer edge of the free - suspended island.
collagen polymer gels are important biological examples of  athermal " biopolymer gels.   these materials have remarkable mechanical properties : even though the constituents are in the linear elastic regime ( up to the yield point of the network ), the network itself is nonlinear and strain - stiffening. for example, in dilute collagen - i gels the shear modulus increases by orders of magnitude as the strain increases @xcite. here   we extend scaling relations near the central - force isostatic point ( cfip ) to the nonlinear regime. as simplified models of real biopolymers we use simulations on two different disordered lattice models, the diluted triangular and kagome lattices, which have maximum coordination @xmath20 and@xmath16 ; they represent two classes of gels with a mean coordination number of @x math = 0.19 and @x maths = 1, respectively. using these lattices we show that the scaling laws of the bio - mechanical properties of biopolymeric networks can be extended to more realistic systems.
the maxwellian theory of electromagnetism is under fire for its inability to handle a lot of situations that in the common practice are instead considered trivial.   the main criticism is that the system is overdetermined, i.e., solutions must satisfy too many constraints without enjoying the necessary degrees of freedom. by trying to impose all of the constraints that a max well - defined solution has to satisfy, one inevitably comes to contradictions. here   i present a new model of maxwell s equations that strictly includes the solutions to maxwell's equations, thus providing the description of a wider range of events. as a consequence  , it is possible to study a wide range of phenomena that are very easily modelled by the new set of equations, such as non - dissipating compact - support electromagnetic waves, travelling straightly at the speed of light, and photons in vacuum.
two new high mass x - ray binaries, bsd 24491 and ls 1698, were found during the rosat galactic plane survey in 1998.   the sources were observed with the _ proportional counter array _ ( pca ) onboard the rxte ( rossi x - rays timing explorer ) in 1998 february. at the time of the observations, both sources were quiescent, with a mean luminosity of 10@xmath9 erg s@x Math7, and a mean spin period of 837 s. the two sources are thought to be accreting binary systems consisting of a neutron star and a compact object that accretes accrets onto it from a nearby compact object.
the @xmath13-matrix theory has been successfully applied to the study of hypernuclei containing both nucleons and hyperons with strangeness.   it has been established that the @x Math13- matrix is energy - dependent and non - hermitian, and does not have the property of decoupling between a model space of low - lying two - particle states and its complement. in this paper   we investigate the effects of the pauli exclusion operator on the effective @x maths5 interaction in finite hypernuclear systems using the yng interaction as a basic ingredient in constructing a microscopic many - body theory starting with bare interactions. by treating rigorously the p Pauli exclusion operators and making a self - consistent calculation of single - particle potentials of hyperons, we show that the@xmath12 effective interaction is not an effective interaction in a formal sense, and that the spin - orbit splitting of the ~1/2-particle levels in the @xcite model is much smaller than that of the experimental hyperon - nucleonic counterpart @x math11.0 ( ~3.4  kcal / mol ). for the same number of hyperiniti
ice nucleation in supercooled cloud droplets is a complex process, and the most crucial question to answer is : what makes an effective ice nucleating center?   we report direct computational evidence that the crystallinity and the hydrophilicity of the carbon surface are strongly coupled to dominate the kinetics of ice formation.   by systematically varying the water - carbon interaction strength over a wide range and computing the iceucleation rates explicitly, we observe a rich spectrum of heterogeneous Ice nucleation behaviors on both crystalline and amorphous carbon surfaces. remarkably, we find that only within certain ranges of hydrophillicity does the crystallogeneity of thecarbon surface play an active role in nucleating ice, and within these ranges, crystalline carbon surface is found to be significantly more efficient than the amomorphous. in other hydrophilic ranges,   the role of crystalline ordering becomes negligible, and no appreciable difference is observed in the directly computed ice nucleations between the crystalline or amorphus carbon surfaces.see research article http://www.biomedcentral.com/1741-7007/1471-2148/9/8/6/3/1
young massive star clusters ( ymcs ) are among the main objects resulting from violent star - forming episodes triggered by galaxy collisions, mergers, and close encounters.   they are also referred to as ` young populous clusters ', a term first coined by @xcite, who used it to describe 23 clusters containing bright, blue stars in the large magellanic cloud. here  , we review the current knowledge of the age of m31 globular cluster ( gc ), the nearest and largest spiral galaxy in the local group of galaxies with a diameter of ~1.5 billion light years.    we show that the observed age of an m31 gc is significantly younger than the age predicted by simple stellar population ( ssp ) models, which assume that all evolutionary stages of the star cluster s evolution are fully populated. using a combination of spectral - energy distributions and spectroscopic observations, we find that the mean age of the cluster is approximately three times lower than that predicted by ssp models, and that the average age of these clusters is about two orders of magnitude higher than that of the old globular clusters ( gcs ) found in the milky way. furthermore, we demonstrate that the
abstractwasp-12b is one of the largest transiting planets discovered so far.   it orbits its host star at an orbital radius of @xmath9, with an orbital period of ~10  d. due to its close proximity to the star, the flux of coronal particles impacting on the planet comes mainly from the azimuthal direction, as the planet moves at a keplerian orbital velocity of@xmath11  km  s@x Math12 around the star. here, we investigate under which conditions the interaction of a planet with the stellar coronal plasma could lead to the formation of a bow shock ahead of the planetary orbital motion, and therefore, explain the early ingress observable in the near - uv.    we find that the shock can be formed when the relative motion between the planetary orbit and the stellar wind is supersonic. for the most extreme case,   the shock configuration depends on the direction of the cosmic flux of particles that arrives at the planet. if the shocked material can absorb enough stellar radiation, the observer will note an early ingression of the planet in the stellar disk, but no difference will be seen at the time of egress, as
sap exudation is a process that occurs in the time period between the dormant leafless phase and the active transpiration phase, when certain processes are triggered that build up positive sap pressure and convert stored starches into sugars.   the mechanism that generates this internal pressure is unique to the sugar maple (  acer saccharum ) and a few other related species ( black and red maple, birch, walnut, and butternut ) whose sap sugar content is also significant although not typically as high as sugar maple. here  , we present a mathematical model that captures the effects of both freeze / thaw and osmotic pressure on the rate of sap exudations in the xylem during the dormant phase and spring thaw. using a combination of experimental and theoretical data,   we show that gas expansion due to thawing sap is the primary cause of the observed pressure changes ; however, the model is unable to account for all observations, and so some authors have suggested that osmosis and gas dissolution could play a significant role in the mechanisms driving sap flow in spring. by simulating the experimentally observed conditions, we find that the model can be used to develop a more
the temperature dependence of the in - plane resistivity in high-@xmath3 cuprates is investigated using a functional renormalization group ( frg ) approach.   the results are compared to the experimental results on overdoped tl2201, which show a linear temperature dependence at high temperature which crosses over to a @xmath5 dependence at lower temperature. for the underdoped side,   an anisotropic term in the quasiparticle scattering rate with an angular form similar to the experiment is found and the temperature dependence increases when approaching optimal doping starting from the overdoped side.
the faust experiment was conducted on board the space shuttle atlantis in march 1992 as part of the atlas1 mission.   it is a @xmath1 instantaneous field - of - view telescope, covering the spectral range between 1400 and 1800  with an angular resolution of 3.5 arcminutes. during this flight 19 pointed exposures were obtained, of which three were short exposures for pointing checks ; the other fixed - pointing images were exposed for 12 to 18 minutes. from the fixed - pointings,   two long scans of the sky were obtained by rolling the space Shuttle during the exposure. using the time - tagged photon stream and subsequent reductions, we identified 4660 uv sources fainter than the completeness limit of the td-1 photometric catalog. here   we present our analysis of four faust fields in the southern sky using data from an objective - prism survey ( hamburg - eso survey = hes, wisotzki 1996 ; reimers 1997 ). all four regions are located in, or very close to, the fourth galactic quadrant, the region of the milky way that lies between the galactic center and l@xmath3270@x math
this paper presents the first study of the near - ir tully - fisher relation, as well as a comparison between stellar and halo masses, for 101 disk galaxies within the redshift range @xmath5 drawn mostly from the deep1 redshift survey.   our goal is to address several questions relating to the mass assembly history of disks. in this paper   we begin this task by investigating the evolution in the fraction of the total mass that is in a stellar form. with some uncertainty  , we compare the _ stellar mass _ of a galaxy with its   halo mass. we find that there is little evolution in either from@xmath6 to @x math7.    this suggests that the dark and stellar components of disk galaxies grow together during this time.
the evolution of the quantum fluctuations in trapped time - dependent bose - einstein condensates is discussed.   the linear field operators will be expanded into their eigenmodes thus permitting the diagonalization of the ( initial ) evolution equations. by adopting the eigen modes,   a much smaller part of the basis needs to be considered and many more situations will become numerically feasible.
precise neutron star mass determinations, coupled with a theoretical knowledge of the pre - collapse mass, can be used to test the neutron star equation of state.   @xcite used the double pulsar system j0737 - 3039 for such a test and inferred from the low mass ( @xmath3 ) of pulsar b in this system, that it formed via an electron - capture supernova ( sn ), an inference first made in@xcite and independently by @oxidite. in this work, we consider the entire sample of known neutron stars with well - measured masses and find that the mass distribution is most compatible with the existence of two distinct populations, a higher - mass ( ~1.5 times more mass ) and a lower - mass population ( ~0.4 times moremass ).    we interpret these two populations to be the result of distinct evolutionary formation scenarios : the low - masspopulation originates in electron - Capture supernovae and has received low kicks, while the high - massPopulation is the result as a result of iron core collapse supernova.
the loschmidt echo ( le ) is a measure of the hyper - sensitivity of the time evolution of a quantum many body system to the perturbations experienced due to the surrounding environment.   it is given by ( t)=| _ 0|e^i h_0 t e^-i h t |(t)|^2,  and is usually interpreted as the overlap of wave functions evolving from the same initial state, but with different hamiltonians @xmath5 and @x math6, respectively. in this article  , we explore the behaviour of the le in a one dimensional interacting system, namely the luttinger model @xcite ( lm ), using a linear protocol from an initial state to a final state. for a finite time linear interaction quench, we study the le for various limits, particularly focussing on the early time ( immediately after quench ) and asymptotic behaviour both for small and large @x Math0.1 and for sudden and adiabatic quenches. within the latter case, we show that the le can be considered as a process that leads to the formation of an interacting liquid from a non interacting
the optical nanofibre ( onf ) is an ultrathin light guide usually fabricated from commercially - available fibre using a heat - and - pull technique.   the enhancement of the spontaneous emission from atoms surrounding an onf into its guided modes is well known @xcite, making it an ideal high - sensitivity tool for channeling atomic fluorescence to a detector. in recent years, onfs have been used as probes for cold atoms @xmath6 atoms/@xmath7 and hot atomic vapors @Xmath8. in the work reported here, atom cloud density enhancement techniques for a sample of laser - cooled @x math0rb atoms are studied in order to increase the fluorescence and/or absorption signals obtainable with onfs.. the density of atoms in a standard magneto - optical trap ( mot ) is limited to @x Math6 atoms /@x maths7 for two reasons : ( 1 ) a transfer of kinetic energy occurs when a ground state atom collides with an excited state atom leading to a trap loss rate that is proportional to the number of atoms trapped and ( 2 ) the outward radiation pressure of the fluorescent light balances the confining forces of the trapping laser beams
we have developed a new method for the detection of very low - surface - brightness ( lsb ) dwarf galaxies in the @xmath7-band survey of the leo i group.   we use the kpno 0.9m+mosaic field of view with eight mosaiced ccds to probe a nearby poor group of galaxies to observational limits approaching those of the local group. as we probe fainter dwarf galaxies, we also probe faint surface brightnesses which approach the limits measured in the local groups. using our optimized method, we find a recovery fraction as a function of the luminosity function ( lf ) of the whole group of dwarf galaxies that approaches the limiting magnitude of@xmath8 ( adjusted for @x math9 ) and is consistent with the results of the best work on the lf of the group to date.
the jacobi metric formalism in relativistic scenario has been applied to massive particle motion in reissner - nordstrm background.   the results show a qualitative difference between the two cases of the probe particle being neutral and charged since in the latter one needs to consider the additional coulomb interaction term between the source and probe particle. for neutral particle the correction terms depend on the charge of the black hole but interestingly for the charged probe particle the charge terms involve both the charge and the gravitational terms as well, showing that the relative sign between the particle and black hole charge becomes important.
nuclear generalized parton distributions ( gpds ) of hadrons are important in their own right because they provide information on nucleon gpds which is complimentary to that of the gpds of the free proton.   traditional nuclear effects ( nuclear binding, emc effect, nuclear shadowing ) are enhanced in nuclear gpds compared to the usual nuclear parton distribution, and nuclear gpd give an access to novel ( or at least not well - established ) nuclear effects such as the presence of non - nucleon degrees of freedom and medium modifications of the quark gpd of the bound nucleon. here   we review recent theoretical results on each of the three aspects of nucleargpds.
solar @xmath3-modes are believed to be excited in the near surface layers of the sun by turbulent convection.   the process can be described as acoustic radiation by turbulent multipole sources, which is driven by supersonic downdrafts in the intergranular lanes and along the borders of the granules. here   we study the excitation and propagation of acoustic waves visible in the solar photosphere using time series recorded with the imax instrument  @xcite aboard the sunrise balloon - borne observatory sunrise   ( june 9, 2009 ). for the first time we find that the acoustic power is not only enhanced at the interranular lanes but also above large granules, where splitting processes are about to occur. a spatially dependent blue - shift over the center of the largest granules   is observed which is consistent with the observation that the energy supply rate of the solar oscillations is stochastically excited by high wave number waves.
the annihilation - diffusion problem of a thermal quench of a liquid crystal film from smectic - a to c phase @xcite is one of the most important problems in particle physics.   the two - species annihilation reaction with long - range interaction ( lri ) can be studied in great detail in a variety of experiments, where the singularities of the director field appear as positive and negative vortices interacting ( due to elastic forces ) via a logarithmic potential. in this paper, we present a new approach to the theory of the annihilation process for the one - species reaction without lri, which is based on the rigorous master equation converted into a renormalized renormalization - group theory for the decay law of the particle density decay in the annihilation reaction. by introducing an additional time scale in the annihilation process, we show that the rate - equation completely neglects all spatial fluctuations and correlations of the initial particle density, leading to a fast decay of the density decay to the non - vacuum equilibrium. instead, we propose a new model for the kinetic annihilation of the particles a and b, both of which are charged and interact via a power - law coulomb type lri.
we propose a scheme for synthesizing topological models in cold atoms using a spin - dependent optical lattice potential consisting of two sublattices with spatial offset.   the key idea in this proposal relies on an optical laser - assisted tunneling technique, which is based on two counter - propagating laser beams that are linearly polarized with the two polarization vectors form an angle @xmath10 with respect to each other, to form the so - called lin@xmath11 lin configuration. by manipulating the experimental parameters of the tunneling,   we show that the topological phase of the lattice can be tuned via tunable experimental parameters, and thus provides a versatile platform to study their intrinsic topological properties.
in student laboratories there is a constant demand for simple and cost - effective laboratory equipment to illustrate modern physics phenomena. in the area of nuclear or particle physics  , radiation detectors can be quite expensive.   commercial detectors also do not offer as extensive learning factors as the " do it yourself " equipment does. in this article   we discuss how a gaseous proportional counter can be built and used to acquire @xmath0- and@xmath1-ray spectra from radioactive sources using a gas proportional counter.
the coupling between the orbital and the spin degrees of freedom of itinerant carriers in semiconductors is a major direction of work in today s spintronics research. here   we provide a complementary theoretical study of cyclotron motion and magnetic focusing under the influence of spin - orbit interaction using a fully quantum mechanical approach.   the authors report on numerical evaluations of the full quantum mechanical dynamics of a free electron in a two - dimensional quantum well with spin - space interaction and a perpendicular magnetic field, avoiding any further approximation. for both conduction - band and valence - band electrons,   all the necessary properties of the rashba hamiltonian model in a parallel magnetic field are obtained by means of a simple solution of the four - component dirac equation for the first few ten lowest landau levels. as a consequence  , the results show that the spin - dependent energy splitting of the ferromagnetic subbands of the quantum well can be controlled by a strong in - plane component of the magnetic field acting on the spin of the travelling electrons.
the skyrme model is a classical field theory which describes atomic nuclei and their low energy interactions.   it is a non - linear theory admitting topological solitons, so - called skyrmions, labelled by a topological charge which can be identified with the baryon number. when the theory is coupled to a fermion field two different ways of describing fermions appear in the same theory. here   we derive the dirac equation on a @xmath0-sphere of radius using the original model. for the first time we show that the spectrum of the fermionic zero modes in the background of a Skyrmion is consistent with the results obtained numerically.. the spectrum for more general shape functions is also evaluated numerically and compared with results in the literature.
we propose a simple and easily parallelizable monte - carlo algorithm based on the fano representation of quantum states and quantum operations.   we show that our algorithm provides reliable results for the case, most significant for present - day implementations of quantum information processing, of single - qubit quantum channels. in this paper  , we consider the problem of discriminating two quantum channels using an ancillary hilbert space where the input state is a density matrix and the output states are entanglement with a quantum system. to achieve this,   the diamond norm is optimized over all possible input states, including those entangled.. the performance of the proposed algorithm is compared with that of the kitaev s characterization of the diamondnorm.    furthermore, in the Fano representation quantum operations are described by affine maps whose matrix elements have precise physical meaning : they are directly related to the evolution of the expectation values of the system s polarization measurements.
the photochemically active azobenzene molecule, @xmath0-tetra-_tert-(ch@xmath12)->butyl - azobazene ( tba ) @xcite, is photo - isomerized between its planar and torsioned - twisted conformers in both solution and gas - phase.   the switching properties of this molecule have been highly sensitive to the adsorbate - substrate interaction : even at nearly chemically inert close - packed noble metal surfaces, switching of surface - adsorbed tba by light has never been achieved, and switching by excitation with a scanning tunneling microscope tip has been successful only at au(111)@xcite. here   we use density - functional theory calculations to investigate the effects of the presence of the tba butyl groups on the surface chemical bond as characteristic for organic molecules containing highly polarizable molecular switches. using a periodic supercell approach, we show that the vdw contributions of the surface dispersive van der waals are substantially larger than those of the bulk adsorption system, and that the effect of the diazo - bridge bond length and the dihedral cnnc angle
we introduce magnetic solutions of the einstein gravity in the presence of a nonlinear electromagnetic field and find the effects of the nonlinearity on the properties of the solutions.   the presented solutions are very flexible and there is not any restriction on the non linear parameter @xmath3 and one can fix it for consistency to other theoretical and experimental evidences.
the atlas experiment @xcite at the large hadron collider ( lhc ) at the university of california, san francisco is one of the most important experiments in the field of particle physics.   it is used to monitor the phase between the collisions and the time - related timing signals that drive the atlas front - end electronics for the detection of bunches of electrons passing through the x - ray tunnel at the largest hadroncollider. here   we describe how the beam pick - up detectors ( bptx stations ) installed along the lhC beam pipe are used to detect the phase of the collisions as input to the trigger system which selects the events to be analyzed by the subdetector front - ends of the experiment. using these events,   the intensity and longitudinal length of the individual bunches are measured and the structure of the beams is determined. with the help of a deep - memory, high sampling rate ( 5ghz ) oscilloscope, this information is transferred to a computer running linux for further analysis. since most of the high - frequency content of the Bptx signals is attenuated by the long transmission line, the frequency spectrum of the signals arriving
abstractparticle detection with low - background liquid / gas xenon detectors offers world - leading sensitivity to hypothetical dark matter particle scattering events.   however, electron train backgrounds present a serious limitation to this technique, due to the fact that they consist of numerous single electron signals, typically of width @xmath6s, emitted over timescales@xmath7s.    the time profile of this background is therefore sparse and long - lived compared with typical event durations, which are @x Math8s. in this work, we show that the origin of the electron train background might lie in the thermalization and trapping of un - emitted electrons just below the liquid xenon surface, with eventual emission on significantly longer timesc scales than previously hypothesized. using a combination of experimental data and theoretical calculations,   we demonstrate that the thermalized, trapped electron hypothesis appears to be correct and that the background can in fact be quantified.
the stability and transitions of basic flows for the stratified rotating boussinesq equations are studied in this article.   the first is a rigorous and complete bifurcation and stability analysis near the first eigenvalue of the linearized problem, and the second is the onset of the hopf bifursation, leading to the existence of periodic solutions of the model. here  , we derive two critical rayleigh numbers @xmath0 and @x math1. using these numbers, we study the stability and transition of the atmospheric and oceanic flows in the presence of different topography and a forcing jet. as a result, we find that the equilibrium state of the system is stable at the beginning of the hopping phase, while the steady state is unstable at the end of the hopsf phase, and both phases are stabilized by the formation of a periodic solution of the original partial differential equations.
the random phase approximation ( rpa ) for electron correlation is a widely used method in quantum chemistry, but its practical applications are often hindered by the very slow convergence of the rpa - correlation energy with the basis set dimension @xcite, which is related to the electron cusp problem.   the goal of the present work is to create a set of benchmark complete basis set ( cbs ) rpa absolute correlation energies for light elements and to validate some extrapolation schemes for the calculation of cbs rpa correlation energies using semiempirical techniques based on the perdew - burke - ernzerhof ( pbe ) exchange - correlation functional from density functional theory. as a result  , we show that the proposed extrapolations schemes are able to achieve good results, with mean absolute errors close to 1 mha and mean relative errors smaller than 1%. however, the convergence behavior of these schemes is not always consistent with the experimental data, and the reliability of the extrapolation schemes for atomization energies is tested using a significant error cancellation effect.
the most popular progenitor model of long - duration gamma - ray bursts ( grbs ) is the collapsar model, which implies that the progenitors of these bursts are associated with regions of high - mass star formation, which might reveal themselves by a detectable extinction in the grb host galaxies along the lines of sight towards the burster.   the present paper is the third in a series of papers where we employ a large database of photometry gathered from the literature to reanalyze all optical afterglow light curves of grbs in the pre-_swift _ era in a consistent manner to derive a homogenous sample, which is then used to study afterglowing properties in a statistical way. here   we extend this systematic analysis to the spectral energy distribution ( sed ) of grb afterglows in the optical / near - infrared bands in order to search for signals from extinction by dust in the gabaa - like galaxies of the gr b host galaxies.. the results show that the majority of the afterglowed galaxies are likely to have been formed by supernovae, and that the observed extinction in some of these galaxies can be explained by the presence of low - mass
the x - ray source ms1603.6 + 2600 was discovered in the einstein extended medium sensitivity survey @xcite and associated with a faint ( @xmath0 ) optical counterpart designated uw  crb.   its nature has remained a puzzle, and the authors have not been able to identify any bursts from the optical counterpart. here   we report rapid optical photometry of this source over several nights from 2004 april 1626 using the argos fast ccd camera@xcite on the mcdonald observatory 2.1 m telescope. for the first time  , we show that the source is not only a dipper but also a low - mass x -ray binary ( lmxb ) with an orbital period of 111.04min and a type - i burst in the optical. during the night of april 18, 20, and 26, we obtained 25h of good data from the source, which were taken as a continuous sequence of images with negligible intervening dead - time. at the end of each night, we observed a series of bursts involving a brightening of a factor @x math1, including both optical and ultraviolet bursts. among the bursts,   the
we study the quantum properties of multiorder sidebands generated by the beating of a quantum probe field with a prepared raman coherence in a far - off - resonance medium. under the conditions of negligible dispersion and limited bandwidth  , we derive a bessel - function solution for the sideband field operators.   we show that, with increasing the effective medium length or the raman sideband order, the autocorrelation functions, cross - correlation functions, photon - number distributions, and squeezing factors undergo oscillations governed by the bessel functions. meanwhile, the normalized autocarrelation functions and normalized squeezing factors of the single - mode probe field are not altered and can be replicated into a broad comb of generated multiorder ramansidebands. to study the mixing and modulation of photon statistical properties in the case of two - mode input, we analyze the effects of the pre - existing medium length and the preparation of the r Raman coherence on the experimental results.    we show how the prepared rRaman coherent and the medium length can be used as control parameters to switch a sideband fields from one type of photon statistics to another type, or from a non - squeezed state to a squeezed state
detecting a very weak signal which is almost inaccessible within the classical ( i.e., non - quantum ) regime is one of the most important subjects in quantum information science.   a strong motivation to devise such an ultra - precise sensor stems from the field of gravitational wave detection, e.g., the variational measurement technique @xcite or the quantum locking scheme@xcite. as a consequence, in this paper we set the goal to develop a general systems and control theory for engineering a sensor achieving _ back - action evasion ( bae ), for both the coherent feedback and the direct - interaction configurations. using the geometric control theory, we first demonstrate that the general synthesis problem of a bae sensor can be formulated and solved within the framework of geometric control theoretical problems, particularly the disturbance decoupling problem. then, we provide the general theory for designing a coherent feedback controller achieving bae, and demonstrate an example for an opto - mechanical system. in section   4, we discuss the case of direct interaction scheme, also based on the geometrical control theory. finally, in section 5, we present a convenient method to find an approximated bae controller and show how much the
the chemical master equation ( cme ) approach is a theoretical framework within which intrinsic noise in biochemical systems is studied.   a widely used numerical method to exactly implement the cme is gillespie algorithm @xcite, as it is often not easily analytically tractable. in this paper, we study the effect of noise on periodic stochastic resonance ( psr ) and aperiodic stochastically resonance ( asr ) in the chemical brusselator system using gill Gillespie algorithm.. furthermore, we explore the effect on psr and asr due to the interplay of extrinsic and intrinsic noises. apart from that, we revisit the coherence resonance ( cr ) and another noise driven phenomenon to make some interesting observations.
we present a new class of solutions in the signum - klein - gordon model @xcite.   the new solutions are quite interesting because they merge properties of shock waves ( discontinuity of the field at one end ) and compactons ( quadratic approach to a vacuum value at the other end ). for these two types of solutions we propose a mechanical system which in the limit of an infinite number of degrees of freedom is described by the lagrangian, which is a polynomial term that can be used to violatate an exact scaling symetry. as a consequence  , we show that the system can be considered as a non - topological compact solution.
the transfer matrix method is used to define the effective dielectric tensor of deformed helix liquid crystal ( dhflc ) cells with subwavelength pitch ( also known as the _ short - pitch dhflcs_.   this case is of particular interest because it is the most important one in the field of electro - optical sensing of ferroelectric liquid crystals ( flcs ).   the applied electric field induces a biaxial anisotropy and rotation of the in - plane optical axes produced by the electric field that can be interpreted as the  orientational kerr effect.  in this work   we use the transfer matrix approach to study the effects of the applied electrical field on the polarization gratings of a set of dhfl cationic liquid crystals, where the cell is confined between two parallel plates subject to homogeneous boundary conditions and the bulk helix is suppressed by the surface induced unwinding of the flc helix. for the first time  , we show that the experimental data are consistent with the theory of the oblique incidence of the optical axes in the direction of the applying electric field. using the differential energy dispersive x - ray diffraction ( d
the electron transmission through a domain boundary in graphene multilayers is studied by using the tight - binding model and the transfer matrix method.   the results show that the boundaries generally suppress the electron transmission in comparision with the perfect bernal stacked system, while the reduction becomes gradually weaker as increasing the number of layers. at high electron density larger than @xmath0@xmath1, the even - layer boundaries have better electron transmission than odd -layer boundaries.. we present the qualitative explanation of those characteristic properties of electron transmission via domain boundary by considering the local band structure inside the boundary region.
the aim of this work was to determine the age of a fossil bone found in the course of the archaeological excavation of a workshop for the processing of flintstones at malu rosu, giurgiu, near the danube river, in romania.   the bone was subjected to radiocarbon dating using accelerator mass spectrometry ( ams ) and the results were compared with those obtained by neutron activation analysis ( naa ). among the isotopes detected by ams, @xmath0c was the most abundant, accounting for about 1% of the total number of atoms in the bone sample. according to the naa results, the bone samples were divided into two groups : the first group consisted of specimens of fossil bones that have undergone a degree of diagenesis, and the second group of specimens that have not undergone any such alterations.    the results show that the mean age of the fossil bone is about 20,000 years.
the self - similar model of galaxy formation relies on the assumption that groups are scaled - down versions of large clusters.   we present a preliminary test of this assumption in a cosmological hydrodynamic simulation, and find that on group scales, the self - similarity scaling relations are not followed, and that features can arise that quantitatively mimic a pre - heating model. to account for this finding, we recalculate the x - ray luminosity of groups using only hot particles, ignoring all particles with @xmath28k. the results are consistent with observations, but more detailed modeling may improve agreement.
population dynamics is a venerable and important subject that has been studied thoroughly for decades.   the importance of fluctuations in the equations of population dynamics has been recognized and analyzed in various ways, most prominently in works that deal with a master equation description of the population instead of a reaction - diffusion model. here   we take a different approach to the problem, our interest lying in an analytic formulation of the problem of internal fluctuations and their consequences. using a one - dimensional bounded population model, we show that the stochastic contributions to the population equations can be accounted for by a variety of sources, including variations in the external environment in which the population evolves, and appear as a fluctuation in the parameters of the equations. when the population is very small, these fluctuations tend to decrease, and the results are consistent with the observation that the per capita growth rate tends to decrease as the population size decreases.
the study of networks has experienced enormous growth in recent years, providing foundational insights into numerous complex systems ranging from protein interaction networks in biology to online friendship networks in the social sciences @xcite.   however, data on mutually - antagonistic interactions  i.e., individuals who directly fight or compete against each other  have been more difficult to collect. in the present paper, we consider head - to - head matchup between major league baseball ( mlb ) pitchers and batters : pitchers benefit by  defeating " batters, and vice versa. using data from retrosheet.org, we characterize the more than eight million mlb plate appearances from 1954 to 2008, considering full careers by examining head -to - head matchups over a multi - season (  career " ) network and single - season performances by constructing networks for individual seasons. using these networks, we construct a quantitative, systematic, and transparent ranking methodology across different eras and examine the interplay between these dynamics and the underlying graph structure. as a result  , we show that the biased random walker dynamics that we employ as a ranking methodology can be used to rank players across eras and for single-season networks. in particular, we find that the results of our
we discuss the design of a wide - field optical and infrared imaging survey for constraining dark energy.   we focus on the use of weak lensing to measure the mass of the dark matter in the universe and its relationship to the cosmological properties of the universe, and how the size of the survey might impact its scientific value for constraining dark energy by measuring the photometric redshifts of the light spectrum of the source galaxies using a variety of complementary observational probes. given the time and cost of a survey, does a large area, shallow survey in a small number of filters provide more scientific return than a deep survey that covers surveys of 1,000 - 20,000 square degrees in 5 - 6 filters but sampling only a few hundred square degrees?
the main theorem in pointwise asymptotic formulas on flat surfaces of a. eskin and h. masur is proved.   they prove that on strata of quadratic differentials on the two dimensional torus @xmath2, parametrizing half translation surfaces, there exists almost everywhere a limit of the growth rate and it is constant ( with respect to a natural invariant liouville measure ). if the number of cylinders of periodic orbits ( po ) or saddle connections ( sc ) of length less than < 0.1 n is denoted by a given marking then the existence of the limits is proved for every constellation of marked points i.e. for all@xmath11\in { { \mathbb{t}}^{2n}}$ ] for all x, y. the limits are established by counting lattice points of certain lattices in the universal cover of @x Math12 of the torus. as a biproduct of this method   we conclude that there is a subset @x math14 ( which depends on what one counts : saddle connections or periodic families ) of measure one in the parameter space of all n markings ( contained in the set
yz  cnc is a member of the class of su  uma type dwarf novae, in which short outbursts are occasionally interspersed by longer and brighter superoutbursts.   its orbital period is 0.0868(2)d ; a more accurate period of 0.86924(7)d is suggested by van paradijs et al. in this paper   we report on a rosat campaign intended to determine the x - ray fluxes throughout the outburst cycle of yz  Cnc ; and also to determine whether the orbital variation in the ultraviolet lines is accompanied by orbital variations in the x-ray flux. during the whole outburst cycle   there is a significant increase in the number of x - rays from the white dwarf, but only at the outermost part of the observed orbital timescale ( ~1.5  years ). for each orbit   the uv emission profiles change from almost pure emission to p cygni profiles with deep absorption, and back again ; these changes are not accompanied by changes in the continuum. as a result   it is possible to distinguish between the two models of the dwarf nova outburst cycle.
wilson lines defined on closed contours are called wilson loops, and they are path - dependent non - local functionals of the gauge field, invariant under gauge group transformations.   the schwinger - dyson equations for the makeenko - migdal ( mm ) equations are grounded on the mandelstam formula and/or on the stokes theorem, so that the wilson functionals which do not satisfy the corresponding restrictions ( such as, e.g., cusped light - like loops ) apparently can not be straightforwardly treated within the same scheme. in the present work   we propose and discuss a new approach to these issues, having in mind, as an instructive example, a very special type of wilson loop  planar rectangles with light -like sides. using the recently conjectured duality between the @xmath17gluon planar scattering amplitudes in the@xmath18 super - yang - mills theory and the vacuum average of planar wilson polygons formed, correspondingly, by @x Math19 light - Like segments connecting space - time points, we show that the infrared singularities of the former corresponds to the ultraviolet
we present a method for reducing a general quadratic theory of gravitation to a canonical second - order form.   we show that the vacuum structure of the transformed theory is non - trivial, and that the elementary field excitations are not related to the equations of motion in the reduced theory. by considering higher - derivative theories of gravity, which involve more than two derivatives on the metric, we find that these theories have a much more complicated vacuum structure than the quadrastic case.
the theory of sound - like collective excitations in a pure neutron superfluid liquid is presented.   the effect of the fermi - liquid interactions on the collective motion of the triplet condensate in the bulk matter of neutron stars is reduced to a set of molecular fields, which are derived from the bcs approximation of the effective vector field given by the sum of external and molecular fields. for the first time   this approach allows to avoid any explicit form of the interaction in the pairing channel.the theoretical model is applied to the polarization function of a triplet - correlated superfluid neutron liquid ( @xcite ) at low temperatures below the critical value @xmath2 under the influence of the proton - neutron interactions. as compared to the classical theory of isotropic pairing, the theory of single - wave pairing in superfluids is designed only for extremely fast waves with a velocity that is very large as comparedto the fermani velocity. since the combined effects of spin - orbit and tensor interactions between neutrons are known to dominate at high densities, the combination of these interactions can not be described with the aid of a sole coupling constant. instead, the recombination of the two channels
quantum teleportation is the process where a quantum state is transferred from one system to another one at a different location.   it relies on quantum entanglement, the most peculiar trait of quantum mechanics. in this work   we propose and simulate numerically a scheme to perform quantum deterministic teleportation of electrons in a device consisting of three couples of semiconductor quantum wires using surface acoustic waves ( saws ) as a means to inject and drive carriers along the wires. for the quantum operations for the teleportation scheme we employ three elements : an electronic beam splitter, a phase shifter and a coulomb coupler. through the coupling between the two wires of a qubit,   the quantum state of the particle to be teleported is encoded through the localization of a single electron in one of two parallel quantum wires. by introducing a suitable potential potential into the quantum wires, which is able to split an incoming wavefunction into two parts  , we are able to obtain the necessary bell states needed to perform a bell measurement@xcite.
superclusters are the largest structures in the universe, and their sizes span the range from a few times the radius of a typical galaxy cluster to the lengths of the " great walls" of galaxies observed by the cfa redshift survey and the sloan digital sky survey.   because they are so large relative to a typical survey volume, superclusters have proven difficult to study, especially in a statistical manner. here  , we use a new, high - resolution, parallel dark matter simulation code that uses the concordance cosmological model to investigate the properties and evolution of supercluster formation and evolution from early cosmic times ( i.e., from redshifts of order unity ). using this code, we show that supercl clusters and in turn superclusters can be identified in the simulation output, and we provide quantitative descriptions of the multiplicity and size distributions of the identified superClusters.    we also examine the radial structure of our superclusions and the dimensionality of these clusters with respect to the data from the sdsss and cfa surveys. ipsilateral to the time of the simulations, we find evidence for the existence of two distinct types of super
the detectability of gravitational waves emitted by newly born neutron stars as they spin down due to the _ r  r:-mode instability is investigated using a phenomenological model adapted from the one proposed in ref.   @xcite, taking into account another nonlinear effect : differential rotation. for different values of differential rotation,   the characteristic amplitude of the gravitational wave signal with the rms strain noise in the initial ligo, virgo and advanced ligo gravitational - wave detectors can be found to be much smaller than unity, whereas for the frequency - domain gravitational waveform it can be detected by the enhanced version of ligo if sources are located at distances up to 20 mpc from earth.
in the early universe, a scalar field often oscillates coherently after inflation.   such a coherent oscillation may have various cosmological effects such as generation of curvature perturbation, dark matter, baryon asymmetry and unwanted relics. in this paper, we revisit the scalar dynamics for @xmath15 with a monomial potential in a general background equation of state. here  , we show that the actual dynamics of the Scalar field is far from both the oscillating solution (  ) and scaling solution ( ).. instead, a peculiar feature of the scalpar dynamics shows up, which we call a " pseudo scaling solution ". by taking into account the hubble mass term,   we find that the pseudo scaling problem can be solved by considering the lagrangian of @x Math17 where the energy of the quantum gravity is equal to the effective mass of the space - time scalar.
the presence of dust grains in the diffuse intergalactic medium is still an open question.   if they exist, they should have great impacts not only on our understanding of galaxy evolution but also on interpretation of high - redshift observational data. here  , we present the results of our deep observations toward the central region of the coma cluster ( abell 1656 ) with the multiband imaging photometer for _ spitzer _ ( mips ) on board the   spitzer_ space telescope. using the far - infrared spectroscopy, we find that the excess emission from this cluster can be attributed to thermal emission from the dust grains detected by @xcite and @xmath7. however, based on the brightness ratio at each wavelength, the contamination of the galaxies is not removed and the detection of the extended excess emission is still limited due to the cirrus noise.
we report measurements made using a ground based gamma ray telescope of cascades developing under the influence of magnetic fields up to 0.55 g. the observations with the mark 6 telescope operating in narrabri, australia are subject to such magnetic fields when observing objects to the south.   the observational data demonstrate all the effects of the geomagnetic field on cascades which are predicted by simulations and show that the magnitude of this effect depends on the orientation of the image with respect to the direction of the magnetic field at the time of observation. for a telescope detecting cascades propagating along the lines of the field ( with no spreading ), the count rate is higher when the field is at a lower strength than when the shower is propagating in an unfavourable direction.
the critical current in mgb@xmath5, a two - band s - wave bcs superconductor with two distinct bands, is studied using the usadel equations and the eliashberg formalism.   the results are compared with experimental measurements of the critical current near @xmath6@xcite, where the temperature - dependent energy gaps are found to be in excellent agreement with the theoretical results for the full temperature dependence of the central critical current.
aggregation processes in which small objects merge irreversibly to form larger clusters are ubiquitous in nature.   often, aggregation is driven by a constant injection of mass and consequently the total mass grows indefinitely with time. here, we investigate aggregation processes with mass injection where the total merger rate does not depend on the total number of clusters. for such situations, we find that the system develops condensates that contain a finite fraction of the mass. these macroscopic condensate co - exist with microscopic clusters that contain the rest of themass in the system.
the cms - totem precision proton spectrometer ( ct - pps )  @xcite is a joint project of the cms and totem collaborations aimed at measuring the surviving scattered protons during standard running conditions in regular " high - luminosity " fills.   the detector consists of a silicon tracking system to measure the position and direction of the protons, and a set of timing counters to measure their arrival time. for this purpose,   central exclusive production ( cep ) in proton - proton collisions is a unique method to access a variety of physics topics, such as anomalous production of w and z boson pairs, high-@xmath1 jet production, and possibly the production of new resonances. here   we describe the development of a new generation of silicon sensor technology for the ctsp detector that will be used to study cep in the lhc experiment.
complex networks are ubiquitous in the real world, e.g., there are technological networks such as the internet, biological networks like protein - protein interaction networks, and social networks like scientific collaboration networks.   all these networks are sampled from complete structures, and if the size of an entire network is too large to measure some quantities such as betweenness centrality distribution, assortativity, clustering coefficient, etc. due to time complexity, inevitably a sampling process is necessary to identify such networks. in this paper  , we adopt three basic methods of sampling networks and investigate the effect of each method on measuring several well - known network quantities by using the results from the basic methods : node sampling, link sampling, and snowball sampling. for each method,   the sampling fraction is defined as the ratio of the number of nodes that are randomly chosen to that of all the nodes in the original network. with the exception of the link sampling method, the other two methods have no significant effect on the observed bias of the measured quantities. however, the snowball sampling method is more likely to overestimate the mean node degree distribution, the average path length, and the betweennesscentrality distribution than the node sampling and link sampling
the recent development of a theoretical framework for deeply virtual exclusive scattering processes using the concept of generalized parton distributions ( gpds ) has opened vast opportunities for understanding and interpreting hadron structure, including spin, within qcd.   transversity gpds are expected to be more elusive quantities, not easily determined experimentally. in this paper   we carefully address, one by one, the issues of the construction of helicity amplitudes and their connection with the cartesian basis, the @xmath1-dependence, the role of@xmath14-channel spin, parity, charge conjugation and their connections to the gpds crossing symmetry properties, finally giving our conclusions.
we report the construction and characterization of two cryogenic ion traps for trapping @xmath0sr@xmath1 ions at liquid helium temperature.   the traps were built using optical lithography techniques to fabricate a surface - electrode ion trap with a planar aspect, which provides a good thermal anchoring to the cryostat baseplate. in the case of a cryogenic system, we used a laser ablation method to obtain a compatible ion source for the trapped ions. both traps were successfully operated by cooling the trap electrodes to 150 k and then cooling them to 6 k. the experimental results show that the anomalous heating rate of trapped ions can be reduced by up to eight orders of magnitude when the trap is cooled to 6k.the thermodynamic properties of the traps are also improved by cooling these electrodes to 4 k. this work is a continuation of d. berkeland s practice of building simple ion trap systems that can be used to trap ions in cryogenic environments.
we have used observations from the identical _ extreme ultraviolet imager _ ( euvi ) @xcite instruments on board the twin  solar terrestrial relations observatory_ ( stereo ) spacecraft to study the evolution of two erupting prominences in physical coordinates.   we have developed a new stereoscopic reconstruction technique for the images obtained from the twin spacecraft, which allows us to reconstruct the features along the legs of the prominence using a single point of view. during the eruption phase,   the two legs of each prominence exhibit a twisted helical structure, i.e., the filament axis leaves its plane and forms a loop - like structure, such as seen in the transition region and coronal explorer images. by using this technique, we have measured the changes in latitude and longitude of features selected along their legs at several instants of time during the fast - eruptive phase of the eruption of two high latitude northern hemisphere Prominences on 2010 april 13 and 2010 august 1 over a period of a few hours. with the help of the stereoscopic technique developed by us, we show that the shape of the elongated legs of both the eruptingprominences changes significantly during the eruptions.
we propose a hybrid quantum algorithm for simulating the dynamics of a quantum system.   our approach is based on the variational method and we hope that it could be implemented using small - size quantum circuits, i.e.  quantum circuits with a small number of quantum operations and suffering significant noise compared with fault - tolerant quantum computers. in this paper   we show that the proposed approach can be successfully implemented using a classical computer as a'coprocessor'while the quantum computer is in charge of carrying out a subroutine, acting as a quantum processor. to test the feasibility of our approach, we demonstrate its application to the simulation of magic state distillation in a quantum chemistry system.
we report high - significance x - ray detections of bright submillimeter ( sub - mm ) sources at high redshift and the first x - rays spectral constraints on this population.   we find that two of the three identified sub-mm sources are gravitationally magnified by abell 370 and are detected at greater than @xmath12 significance by the submillimetre common user bolometer array in the fields of rich clusters  @xcite and in blank fields for 93 ks with the acis s3 detector, and that they contain a large fraction of the obscured agn thought to be responsible for the diffuse x -ray background.
we investigate the infrared problem of bremsstrahlung in quantum gravity in the framework of causal perturbation theory.   we use the method of adiabatic switching with a testfunction from the schwartz space which cuts off the interaction at large distances in spacetime and it turns out to be a natural infrared cutoff. for the emission of a real soft graviton in two particle scattering, we find that the transition amplitude for a process is logarithmically divergent for virtual and real brems stahlung processes. as far as we know   the cancellation of these divergencies is not at all clear. in this article we show that the problem can not be treated in the same way as in quantum electrodynamics ( qed ) because the decomposition of the infrared divergencies into subdivergences in an arbitrary feynman diagram does not cancel to every order of perturbative theory.
we present a fourth order accurate algorithm for the axisymmetric massless klein - gordon scalar field around a schwarzschild black hole, which employs a cauchy evolution scheme, based on space - like slices, and a characteristic scheme that uses null slices.   the two schemes are connected by a time - like interface, which is implemented with touching grids. at the discrete level   this interface is implemented using touching grids, but when the slices are not simultaneous, this particular multi - grid approach is better suited than overlapping grids, as it avoids complications due to causality. in order to reach future null infinity the radial coordinate of the characteristic region is compactified so that it is parallel to the outer boundary of the interior cacauchy region and coincides with the inner boundary of its interior characteristic region. from the results of experiments with the wave equation in spherical symmetry, we show that the proposed algorithm is more accurate than the existing methods.
the blandford - znajek ( bz ) process is a widely discussed model for the driving mechanism of relativistic jets associated with active galactic nuclei, gamma - ray bursts, and galactic microquasars.   the bz process is based on the energy extraction from a rotating black hole ( bh ) along magnetic field lines threading it, which produces poynting - dominated jets, in which the plasma particles can be accelerated to relativistically speeds. however, the physical mechanism for the creation of the flux in the electromagnetically dominated plasma has not been clearly explained. in this article   we argue that the electric current is generally driven in the non - ideal magnetohydrodynamic region in the time - dependent state, and such regions are hidden near ( or within ) the event horizon in the steady state. as a result, the steady current circuit is maintained without any current driving source, because the force - free plasma has no resistivity.
heavy - quarks are produced in ultrarelativistic heavy - ion collisions via hadronic decays of d mesons and the semileptonic decay of charm and beauty hadrons.   the effects of these decays on the nuclear modification factor of hadrons containing heavy quarks, which is defined as the ratio between the differential yield measured in pb   pb ( or p  pb ) collisions and the cross section measured in pp collisions multiplied by the average nuclear overlap function, are studied experimentally using the alice detector at @xmath0 = 2.76 tev and 7 tev for the prompt d@xmath5,6 and 7 hadron decays and the time - of - flight ( tof ) detector at mid - rapidity ( @x math8 ) for the hadron decay leptons. a detailed description of the experimental results is provided by the perturbative quantum chromodynamics calculations.
we investigate the performance of a fabry - prot interferometer with a transition edge sensor ( tes ) to detect photon - number resolved interference fringes in a coherent state.   we show that the detection efficiency of the tes is very high ( 95% at @xmath1 ) and the average intensity of the interference pattern is resolved to a single - mode quantum state, which provides a better understanding of the interplay of sensitivity and resolution of an interferometric scheme.
we study the consequences of genuine dimension - six ( dim-6 ) higgs operators on the electroweak symmetry breaking of the higgs sector at low energies.   we find that they are more sensitive to the new physics beyond the standard model ( sm ) than the existing ones, and that they can be corrected to a good precision at hadron colliders and future linear colliders by integrating out heavy massive degrees of freedom in a theory beyond the sm.
we report the results of a second, longer, x - ray observation of m@xmath067 with the rosat photospheric spectroscopy probe ( pspc ), and of another old galactic cluster, ngc@x Math0188.   we also reanalyse our first observation of this cluster, and make use of new optical studies of the binaries in this cluster to determine the nature of the x-ray sources.
many undergraduate curricula in physics are organized around first understanding the properties of ordinary differential equations, and often give the impression that these mathematical tools are somehow wedded to the separate subjects of the physics canon, rather than being independent, widely applicable tools.   my aim here is to present a mechanics problem which is usually dealt with in the algebra - based mechanics curriculum and recast it using the mathematical language students expect in electricity and magnetism. as a result, i will connect archimedes principle ( usually developed as a   just - so " statement of how a  buoyant force " works ) to real forces acting on real bodies. by doing so  , i wish to give an undergraduate a context in which vector analysis has a definite application in the most familiar, concrete physics a student knows, namely mechanics.
the measurement of prompt photon cross - section at the atlas detector @xcite at lhc is presented.   the measurements are based on the isolation of photons from the hadronic calorimeter and the subtraction of the background from meson decays and jets using the so - called 2d sideband method. in this method,   photons are divided into four regions ( a : tight and isolated ; b : Tight and non - isolated ; c : non - tight andisolated ; d : non-tight and non-isolated ). for each region, the number of signal photons in data   can be estimated by dividing the total number of detected photons by the average number of events in each category. to estimate the signal number, we use the monte carlo simulation method with pythia 8.165, sherpa 1.4.0, jetphox, and peter detectors. here  , we present the results of the measurement of isolated prompt photon Cross - section which are compared to those of the other experiments.
subdiffusion occurs in many physical systems such as amorphous semiconductors, porous media and gel solvents.   the subdiffusion is defined by the relation @xmath0 with @x Math1, where @x math2 denotes the mean square displacement of the transported particle,@xmath3 is the time, and @xMath4 corresponds to the normal diffusion. while there is a huge literature about the normal diffusive problem in a variety of systems, it is unclear how to apply these approaches to a multi - part system, where the various kinds of diffusion occur ( e.g. a porous material, where subdisintegration proceeds, is adjoined to a normal Diffusive medium ). in this paper   we present a practical method to obtain solutions of the one - dimensional subdiffusive equation with given boundary conditions starting with those of normal diffusion, which can be obtained rather easily using the green s function for normal diffusion as the starting point.
the interference between the higgs signal and the continuum background at the large hadron collider ( lhc ) has been studied for a light, narrow - width higgs boson.   we calculate the dominant next - to - leading order ( nlo ) qcd corrections to the interference, and study the dependence of the mass shift on the acceptance cuts. in this letter  , we also argue that the interference effect can be used to bound experimentally, or possibly even measure, the higgss width fairly directly, for widths well below the experimental mass resolution.
the rubinstein - duke ( rd ) model of polymer dynamics has been widely used to model the behavior of long polymers in a gel.   the model is based on the concept of reptons, blobs of monomers of the size of the correlation length @xcite, which are connected by a chain of slack and taut links. here   we extend the rd model to include additional motions, such as the formation of hernias and the crossing of barriers. using finite size analysis, we investigate the influence of these new motions on the properties of the standard rd models. for the first time we show that the effects of hernia creation and annihilation can be combined with those of barrier crossing to produce a more realistic model.
@xcite graphene is a novel two - dimensional ( 2d ) material @xcite with unique electronic and optical properties.   it is characterized by a large local density of states ( ldos ) of graphene plasmons as compared to that of surface plasmon polaritons ( spp ) on metal surfaces, which ensures very efficient plasson excitation by a local probe such as an excited dye molecule or an exciton in semiconductor quantum dot ( qd ) situated at a close distance to the graphene sheet. here   we show that a strong coupling between excitons and quasiparticles in graphene can be achieved in a hybrid structure comprised of doped graphene monolayer separated by a thin spacer from a narrow gap semiconductor qw. using this hybrid structure,   a propagating exciton - plasmanic state with a mixed 2d dispersion is observed in aqueous solution of graphene and semiconducting qws where the excitations are induced by photoinduced charge transfer from qw to graphene via a strong coulomb coupling.
the existence of massive neutrinos, the unknown origin of parity violation in the standard model ( sm ) and the hierarchy problem are some of the important motivations for physics beyond the sm.   one of the most natural extensions of the sm that addresses these issues is the supersymmetric version of the left - right symmetric extension of the model, which will treat the left- and right - handed fermions on equal footing at low energies and allow spontaneous breaking of the symmetry of the gauge groups at some high scale. in this article   we propose a new solution to the problem of spontaneous symmetry breaking at high scale in supersymmetry models with only doublet higgs scalars by introducing a single singlet higgens scalar, which breaks the asymmetry of the quantum operators at a high scale.we show that the global minimum of the higgs potential can be found to be either charge violating or @xmath2-parity violating depending on the strength of the vacuum that preserves both electric charge and r - parity. using a seesaw mechanism, we show that leptogenesis of the neutrino masses via type iii see - saw mechanism is possible through the introduction of a bi - triplet
the media hype over epidemics threat has a close similarity in how worried or fatalist, resilient, skeptical or cheeky may be friends and neighborhood.   the individual perception of the risk of becoming infected is a key factor influencing the spreading of an epidemics and, toward realistic inference, epidemiological models should incorporate such parameter into their models.. however, the investigations of social networks have shown that they are quite different from regular and random graphs  . the probability distribution of contacts often exhibits a power - law behavior, with an exponent between two and three, which is characterized by a relatively large number of highly connected hubs, which are presumably responsible for epidemics spreading. on very non homogeneous networks, with diverging second moment, this effect is even more pronounced. as shown by watts and strogatz  , the simple rewiring of a small fraction of links in an otherwise regular lattice results in a sudden lowering of the diameter of the graph, without affecting the average connectivity or the degree of clustering. to investigate the effect of risk perception in influencing the spread of a disease, let us start from simple, yet meaningful models, such as sis or sir ones.
the cern large hadron collider is about to start probing directly the tev scale with the study of the electroweak symmetry breaking mechanism being at center stage.   a common feature of many of these models is the appearance of new spin1 states that unitarize the weak gauge boson scattering. in this work   we present a model independent analysis of the observability of these signals. for @xmath6 states   these are the most sensitive channels which can give information on its connection to electroweak symmetric breaking ( ewsb ). for@xmath7 they complement its observation in sm gaugeboson fusion ( wbf ) and provide further information on their properties.
the checkerboard lattice is a two dimensionnal lattice where the elementary cell is a tetrahedron and the connectivity is corner sharing.   it has been recently shown that its quantum ground states are singlets @xcite for finite systems. in this paper   we test wether this conclusion may be valid for an infinite lattice. to do so we start away from the isotropic checkerboards limit, when diagonal bonds are weakened, and we test whether this system undergoes a neel ordering transition when reaching the isotropy limit.    this is done within the frame of the linear spin wave theory and the dyson - maleev approximation @xcites.. the peculiar case @xmath10 is explored within a fermionic large - n limit of the su(2 ) hamiltonian. 	 it is found that the system should order in a valence bond solid of disconnected 4-spins singlets. as the number of atoms in the system increases from 1 to 2, the number at the top of the lattice decreases and the square lattice becomes more and more complex. on the other hand,   the size of the center of the
we present the results obtained with a gsfc pixel read out both in the ac and dc configuration of an x - ray tes microcalorimeter.   the results show that the performance of the tes under dc bias is significantly lower than that under ac bias, and the effect of the perpendicular magnetic field and the voltage bias on the detector response is well studied.
quantum chromodynamics ( qcd ) and the gluon field are the building blocks of the strong - coupling theory of quantum mechanics.   the two - point green function is one of the most basic quantities to describe the motions and the interactions of particles in qcd, but most green s functions of quarks and gluons are still unknown in the nonperturbative description. here  , we propose a new framework for the analysis of the green function of gluonic properties in terms of color confinement and spontaneous chiral - symmetry breaking from qcd. by means of the gribov horizon analysis,   we show that the infrared singularity of the glUon propagator, which is a basic quantity in q cd, is not only independent of the gauge choice, but also depends on the intensity of the interaction between the two points of the propagator and the ground state, and can be explained by the generalization of the red - shift mechanism of the classical qcd model based on the pomeron phenomenology. as a result of the application of the new framework, we find that the effective - mass generation of the glueball states, which are color - singlet bound states
we study the relationship between the onset of chaos in the dicke and tavis - cummings hamiltonian and the singular behavior of the excited - state quantum phase transition ( esqpt ) and ground - state energy in the semi - classical approximation to the density of states ( dos ).   the results show that the presence of chaos is only present in the energy region where the quadratic approximation of the ham Miltonian fails to describe semiclassical model dynamics.    the onsetof chaos is caused by the precursors of the second - order quantum phase transitions ( qpts ) occurring in the superradiant phase, which occur when the top of the double well or mexican hat potential that develops in the Superradiant phases is attained.. the onset has been shown to be independent of the coupling constants and the excitation energy.
the study of extra - solar planets has become one of the key research areas in astronomy today.   transiting systems provide a radius, and hence bulk density when coupled with the planetary mass determined from radial velocity follow - up, as well as characterising their atmospheres with techniques such as transmission spectroscopy and secondary eclipse photometry. since the bulk density is measured by determining the radius of the planet from the transit lightcurve, and assuming a spherical planet, a simple bulk density calculation can be applied to work out the volume of the distorted hot - jupiter. here  , we present a simple model to estimate the distortion of the bulk densities of short - period exoplanets using observed parameters gleaned from transit photometry and radial - velocity measurements. for this purpose, we use the roche approximation to model the gravitational interaction between the parent star and the planet, and show that tidal distortion can be significant for hot -jupiters with orbital periods less than @xmath02 days. while the tidal distortion is negligible for systems with orbital separations of < 10.1a.u., it is significant for systems having orbital separings of > 10.0a.o.
the alice experiment is dedicated to the study of the properties of qcd matter created in nucleus - nucleus collisions at lhc energies at @xcite.   the inner tracking system in the alice apparatus is made of position sensitive detectors which have to handle several thousands tracks per unit of rapidity and are capable of detecting particles with open heavy - flavour @xcite. the performance of the tracking doublets, together with a detailed cluster analysis of the hits, can yield a good determination of the intrinsic spatial precision and detection efficiency of the pixel plane under test. in the 2002 beam test, where the sensor thickness ( 200 @xmath13 ) was the same as the one used in the ladder production, a study of detector performance as a function of the threshold and the track incidence angle is presented. some comparisons with the main results for the thicker sensor   are also discussed.
we have measured the low - frequency resistance fluctuations ( 1 mhz@xmath0f@x010 hz ) in ag nanowires of diameter 15 nm @xmath1 d @x Math1 200 nm at room temperatures.   the wires were electrochemically grown in templates of anodic alumina or polycarbonate and characterized by x - ray, sem and tem. to our knowledge   this is the first report of the investigation of 1/f noise in nanowire in this range of diameters.
we theoretically investigate spin - resolved currents flowing in large - area graphene doped with single atoms of noble metals and transition metals.   we show that the current polarization is not monotonically correlated to the local magnetic moment, but rather depends on the presence of localized levels near the fermi energy which strongly couple ( and thus hybridize ) to the graphene @xmath8 bands. a gate potential can be used to tune the energy of these localized levels, leading to an external way to control the degree of spin - polarized current without the application of a magnetic field.
we propose a method for the production of stop particles at the lhc in association with a hard photon or a hard jet.   the lightest supersymmetric particle ( lsp ) may be produced in decays of heavy gluinos, which may then decay into a pair of equal - sign top quarks plus two equal -Sign stops. to achieve this goal,   a soft photon is used in the co - annihilation region of the stop   neutralino co - annihilation region, in which the neutralino - stop mass difference is controlled by the mass difference of the stopping quark and the charging neutralino. as a result  , there will be minimal hadronic activity associated with the stop decays, and the energy of the decays does not depend on the assumption of a relatively light gluino. however, it is possible to produce stop particles with masses below about 10  gev   @xcite if the collider is equipped with a large number of hard photons and/or a high - energy jet.
the energy resolution of scintillation detectors increases with the area of the photon sensor.   a larger detector volume has a higher sensitivity for radiation detection. to achieve this, it is necessary to use multiple silicon photomultipliers ( sipms ) to increase the efficiency of photon collection for a larger scintillator. in this work,   scintillediculus detectors are constructed and tested with a custom 2x2 sipm array using geant4 simulations on a 6x6 mm@xmath3 silicon photomaultiplier tube ( sipm ) array that has four sipms arranged in a 2-x2 configuration. since the sipms are arranged as a square or rectangle in the array, scintillary detectors with a square cross section have a better energy resolution than those with a circular cross section.
we show that rotation - invariance violation in newton s second law is a general field - theoretic framework for studying lorentz violation.   we use the standard - model extension ( sme ) to study this problem using a block on an inclined plane devoid of friction, and show that observer rotation invariance holds, while a particle rotation changes the outcome of the experiment, violating Lorentz symmetry.
the continuum limit of super yang - mills theory is studied on the ` ichimatsu'lattice, a novel lattice.   the continuum limit is obtained by analysing the phase diagram of the gauge sector and its limiting cases. in order to be consistent with confinement and asymptotic freedom, the phase diagrams must be smoothly connected between the weak and strong coulping regions.
abstractthe trapezium cluster in orion is the nearest young, massive star forming region in the orion nebula.   its central core is dominated by a single star of spectral type o6ep, 1c, which dominates the ultraviolet radiation field and ionizes the gas cocoons around nearby low - mass stars. as the ionized gas is unbound and evaporates from the stars, the photoevaporating protoplanetary disks, or proplyds, are exposed to ultraviolet radiation and undergo photoionization and evaporation of molecular clumps within hii regions. using the hubble space telescope ( hst )  , we have imaged two fields of the cluster core at @xmath12  mm with the plateau de bure interferometer and found that the average mass of the proplyd is @x Math11.5  myr.    this is twenty times lower than the minimum formation mass of our solar system and thus it is not likely to be a candidate for planet formation on scales of our own solar system.
according to the special theory of relativity a clock located at the equator should run slower than one at the pole.   all clocks located at sea - level on the earth s surface tick at the same rate, regardless of latitude. in this article sam and kim discuss the relativistic effect of placing clocks at high altitudes.
we have obtained moderate, and lower resolution, @xmath1-band spectroscopy of three of the brightest catastrophic variables ( cvs ) : ss cyg, ru peg, and gk per.   we use a modified version of the moog spectral synthesis program to model moderate resolution @x Math1- band spectra to examine the atomic and molecular abundances in their secondary stars. for each of the three cvs, we find that the secondary star dominates the accretion disk flux in the @x math1-bands, and any veiling has to be quite small. using the best fit model spectra derived from the higher resolution data to lower resolution data, we show that the co features of the secondary stars in these cvs are much weaker than expected for their spectral types.
the g331.512@xmath00.103 molecular cloud is a giant, elongated ( 178 by 41 pc ) cloud in the norma spiral arm, at a distance of 7.5 kpc.   it is one of the most active and extreme high - mass star forming environments in our galaxy. here   we present observations with the atacama large millimeter / submillimeter array ( alma ) that resolve the outflow properties of this molecular cloud, allowing derivation of the out flow properties including age. using alma band 7, we observed a single field of view centered at @x Math7, @xmath8.    the data were processed using the common astronomy software application ( casa ; *????   * ), and the resulting maps have cells with sizes of 0.14, with 254 cells in each spatial dimension. while a rich spectrum of lines was observed,   this letter focuses on the lines of sio(8 - 7 ) ( 347.33058 ghz ), h@x maths11co@x math12(4 - 3 ) ( 346.99835 ghz).the outflow and its interaction with the surrounding
we propose a memetic algorithm for the np - hard minimum sum coloring problem ( masc ), which relies on three key components.   first, it uses a double - neighborhood tabu search procedure to explore the search space and a multi - parent crossover operator to transmit large color classes from the parents to the offspring. in addition, a population updating mechanism is devised to determine how the offspring solution is inserted into the population. here  , we evaluate the performance of masc on 77 well - known graphs from dimacs and color 2002 - 2004 graph coloring competitions ( 59 of them have been used previously for evaluating sum coloring algorithms ) using computational results and compare its performance with five state - of - the - art algorithms. as a result, we find that masc can frequently match the best known results in the literature for most of the 59 cases. in particular, it improves the previous best solution for 17 graphs for which an upper bound is known. for the additional 18 new graphs, we report computational results for the first time.
the classification of proton nebulae ( pne ) based on their morphology is now clear that it also corresponds to a real physical classification of the ne nebula and of their stellar progenitors.   one of the most extensive analyses is that of corradi & schwarz ( 1995, hereafter cs95 ), who studied in detail the correlation of the morphological properties of pne with several other physical properties, giving particular emphasis to the comparison between the elliptical ( @xmath2 ) and bipolar (@xmath0 ) pne. here  , i will add some comments to the discussion of those properties which appear to be most important for understanding the formation of the different morphological classes and discuss whether these put real constraints on the models and present some other recent results on.
the interaction between high - energy jets from active galactic nuclei ( agn ) and their surroundings has long been a topic of great astrophysical interest.   it is well known that agn feedback can control the size of a galaxy by influencing star formation, but the mechanism behind this is not well understood. in this paper, we present a numerical study of the interaction of a full jet with an inhomogeneous intergalactic cloud on the scale of tens of kpc. using a series of numerical models of the minkowski s object ( hereafter m.o. ), a peculiar star forming object located at a redshift of @xmath4 ( c06 ) that is currently being bombarded by a fr i radio jet from the nearby galaxy ngc 541, we show that the jet - cloud interaction can be thought of as " positive " or " negative " based on the exact astrophysical conditions in the jet and cloud. for the positive feedback case,   the model predicts that the warm gas surrounding the jet will cool into the h@xmath0 regions straddling the jet, and the star formation rate will decrease laterally from this point. for both positive and negative feedback cases,
the apogee survey, part of the sloan digital sky survey iii ( sdss - iii ) @xcite, has observed @xmath3150,000 predominantly red giants stars covering the full range of galactic bulge, bar, disk and halo regions.   the results of the analysis of the near - infrared spectra of these stars have been deposited in the ncbi sra database under accession number srp00000000. here  , we present the results for the first time of the nlte analysis of  by the aspcap@xcite stellar parameters and chemical abundances pipeline. using the new data, we show that the effective temperature, surface gravity, metallicity and mass of the stars can be used to estimate the relative abundance of mg in the atmosphere of a to late - type stars with accuracy of up to 0.4dex for giants, and that the ratio of  is a promising discriminant between the two populations.
the exact hybrid monte carlo ( hmc ) is a molecular dynamics based algorithm for full qcd.   we examine here how effective the hmc is in decorrelating the topology for both full q cd with four staggered fermions and pure @xmath0 gauge theory, and compare its performance with an over - relaxed heat - bath algorithm.
we report the results of a new study of the @xmath5gev emission of a compact star and a high - mass star in a binary system.   the star is a b0pe, o6.5v type star in an orbit around a massive star of be type ( ~9.7 iab ) with a very strong surface magnetic field and a large stellar wind. during the asas-3 optical survey @xcite we have observed the spectra of the star and its companion using both radio and x - ray spectroscopy at wavelengths close to 10100mjy. for the first time, we have measured the spectrum of the source from the same position as the star in the binary, lsi+61303, which is located between the monoceros loop supernova remnant and the star forming regions of the rosetta nebula ( @x Math111.4kpc ).    the source is of spectral type b0 pe ( ~8.1  kms@xmath10 ) and is thought to be a compact object with a strong shock heating and shock heating - accelerated stellar wind due to the confinement of the stellar wind in the star's
we propose a hybrid combination of a flux qubit and an ensemble of independent spins, given here by the nitrogen - vacancy  ( nv - centers in a diamond ). by means of numerical studies  , we corroborate that this system exhibits localized and delocalized phases.   finally, we demonstrate that these phases can be identified by monitoring the signatures of the non - equilibrium system dynamics in presence of decoherence and dissipation upon employing experimentally accessible parameters.
fidelity is a standard benchmark in quantum information, and plays a relevant role in discussions on quantum chaos.   experiments with microwave cavities or elastic bodies seem to provide good options to study the decay of fidelity, but a difficulty arises. in elastic experiments on solid blocks or three - dimensional ( 3d ) microwave billiards the wave function inside the volume seems to be inaccessible anyway, and thus the concept of scattering fidelity @xcite was developed to test the sensitivity of @xmath1-matrix elements to perturbations. in the present paper   we realize the system by a flat microwave billiard with two attached antennas and measure the reflection in one antenna while modifying the coupling in another. using random matrix theory and the effective hamiltonian approach, we show that the fidelity decay can be explained by the leakage of the norm inside the scattering system.
conjugated polymers are promising candidates for the assembly of complex nano - assemblies of functional units.   one such assembly might be a self - assembled multilayer with the specific function of transferring holes away from light receptors. in this paper  , we examine phenylene - acetylene oligomers from both theoretical and experimental standpoints in order to analyze their excited state electronic structure and the effects of conformational rotations on effective conjugation and electronic de - localization lengths of these materials. using a blend of quantum chemical methods including semi - empirical ( austin model 1 ( am1 ) approaches for ground and excited state @xcite geometry optimizations, and time - dependent density functional theory ( td - dft ) and zindo@xcite methods for excited state computations, we find that the transition orbital decomposition of the monomer @xicite is more flexible than previously reported. by comparing the results of the calculations to experiment, we show that the conformation of the polymer can be controlled by twisting the benzene rings about the triple - bonded carbon links.. however, this geometry change is expected to reduce the conjugative length of the molecule and may adversely affect applications which rely on the
the noncommutative chern - simons theory is investigated in two natural extensions of our previous work @xcite.   first, we prove that the cancellation of ultraviolet / infrared ( uv / ir ) singularities, generated in the nonplanar part of the quantum corrections to the effective action of the supersymmetric theory, demands that the gauge group generators are in the fundamental representation of the @xmath0 group.    this is the same requirement found for the consistency of noncommUTative gauge models at the classical level and for the existence of dangerous uv/ir singularities in the supers asymmetric model. as a consequence, we find that the finite one - loop quantum corrections can be calculated for the pure gauge sector if the generator is in the basic representation of@xmath1. second, we calculate the finite changes in the coefficient of the chern-simons term and the structure of the effect of the inclusion of matter in the adjoint or the fundamental representations of the non - abelian version of the gauge sector. here  , we show that the effects of the addition of matter are not only additive but also additive, and the latter induces a shift in the classical
blind quantum computation ( bqc ) is a kind of secure computation protocol involving two roles, where the client has the data and the algorithm, and the server has a quantum computer.   the client instructs the server to perform quantum computation on his data without leaking any information about the data, the algorithm and even the final result. in this paper, we review and analyze the main multi - server bQc protocols, and devise a double - server blind quantum computations protocol with completely classical client, where both servers are allowed to communicate mutually. in our protocol, the trusted center should prepare bell states and send them to the servers, and it is necessary that there exists a private classical channel from the trusted centre to the client. for the client to perform a quantum computation, he must have some quantum abilities, such as the ability to prepare or measure single qubits..in addition, the client must be able to perform lots of quantum computation in the quantum authentication encoding.
the formation of scalar hair on charged solitons in asymptotically ads space - time has been interpreted as an insulator / superconductor phase transition.   this is related to the fact that the scalar field of these spherically symmetric configurations is finite inside a ball of radius, but vanishes identically outside this radius. here   we consider boson stars, which are compact in the sense, that their scalar fields are finite inside and outside a ball with a diameter of a few tens of micrometers. using a combination of density functional theory ( dft ) and cosmological calculations, we show that it is possible to set the newton s constant at the probe limit by setting the electric charge of the scalor field from zero to infinity. for the first time we have found a solution of the einstein - klein - gordon equation with a positive Cosmological constant, where both the energy and the temperature of the universe can be set at 0.1  kcal / mol. when coupled to a v - shaped self - interaction potential,   our results show that the existence of a singularity in the presence of a vector field can be
the molecular dynamics method is the most versatile way of describing solid - solid phase transitions.   the crystal and interfacial structures arise automatically from the interatomic potential, as are the long range strain effects and there is no need for the implicit assumptions about microscopic detail and symmetry entailed in continuum methods. in this paper   we discuss a number of issues and questions which have arisen from our work in molecular dynamics, but which tend to be ignored or glossed over in other techniques. along the way  , i discuss a few points which appear to have been ignored in much of the literature, highlight some of the current unresolved issues and include the consensus of many discussions at the meeting in phoenix.
the acis - i survey of 33  ( chasem33 ) is a large program that will accumulate in seven deep pointings, each 200 ks in length, a total exposure of 1.4  ms. during several of these pointings   7  is in the field of view.   we report here on observations of 7  spread over just 20 binary orbits, which resolved for the first time the eclipse ingress and egress and allowed us to constrain the light curve of7  for binary phases around eclipse.
the microtron mami at the institut fr kernphysik in mainz, germany, has been upgraded to 1.5gev electron beam energy  @xcite.   the new electron beam delivers an electron beam with excellent spatial and energy definition that can now be used to study strange hadronic systems produced on solid - state or liquid cryogenic targets. for the strangeness programme the  spectrometer was recently dismantled at the sis facility at gsi and re - installed in the spectrometers hall at mami.   here   we describe the experimental setup and the results of a pilot experiment on the electro - production of kaons off a liquid hydrogen target.
the two - variable integro - differential equation formalism ( idea ) in configuration space is employed to describe the inter - cluster correlations in hot and dense relativistic nuclear matter.   the idea is based on the faddeev formalism, where the a - body wave function can be written as a sum of two - body amplitudes, and the hyperspherical harmonics are used to obtain the binding energy results for the a-body. using many - body green functions,   this formalism is applied to the description of four - nucleon clusters of medium - light nuclei and also to the light front to study the quark correlations in heavy ion collisions at intermediate energies. with the help of the idea method, we show that the effective in - medium equations for the three- and four - body correlations are reduced to the corresponding local potentials for each chemical potential and temperature which are energy - independent. by means of the localization procedure  , we have obtained an equivalent local potential for each potential depending on the number of particles involved in the cluster and the presence of the fermi function. from these results, we derive the reduced equations which are in excellent agreement with variational, green
we introduce a packaging of numerical invariants of knotted 3-dimensional objects into two power series : one that encodes non - perturbative invariants ( model np ) and one that encapsulates perturbation invariant ( model p ).   the paper is concerned with the analytic continuation, the asymptotic behavior and arithmetic properties of those power series. in particular, we consider the witten - reshetikhin - turaev - witten conjecture concerning the structure of nonperturbative quantum invariants and the symmetry conjecture about the existence of symmetric invariants for an oriented 3-manifold using a compact lie group. by means of elementary complex analysis,   we show that the power series can be formulated as a set of power series that are analytic for every pair of pairs @xmath17 where @x Math18 denotes a knotted object, i.e., a knot in 3-space or a closed 3-Manifold in 3 space or a 2- or 3-state gauge group. on the basis of these results, we propose a new formulation of the volume and witten conjectures in quantum topology ; namely, the volume conjecture and the
we propose a new imaging detector of mev gamma rays measuring both the directions and energies of not only a scattered gamma ray but also a recoil electron, which enables us to reconstruct the direction of an incident gamma ray event by event.   the proposed detector consists of a 30 cm cubic @xmath0-tpc surrounded by a scintillation pixel detector, which measures the successive positions of the track of charged particles in a few hundred micron meter pitch using a wireless gas proportional chamber ( @x Math0-pic ). for the energy measurement, analog signals of the amplifier connected to the cathode strips   are summed 32 to one on the amplifier board, and its waveforms are recorded by the 8-channel 100 mhz flash adc ( fadc ). at the first stage,   we have developed a prototype @x math0-ppc having a detection volume of 10@xmath2 10 @x maths2 8 @xMath3. the results of its performance study are presented.
in this lecture series, we discuss two topics :   computational models based on the concept of the continuum and  extended proof systems for more efficient certificates of optimality.   a model of computation provides mathematical abstractions of basic data objects and operations on those objects, available as building blocks. in this model,   the computer implementing discrete turing machine model uses strings of 0 s and 1 s and finite state machines. however, careful study of the work of early pioneers   turing, von neumann and godel  shows that they were acutely aware of the limitations of this model for comprehensive understanding of the fundamental aspects of computation. here   we describe efficient evaluation methods for the effect of exponential number of constraints in the context of continuum based algorithms by considering concrete examples of finding maximum independent set in a graph and the satisfiability problem. objective function for these problems is treated by non - convex optimization methods covered in part 3.
the standard model for the evolution of a comet nucleus is based on the formation of a dust mantle with depleted volatile materials and a crystalline ice crust below the dust mantle.   this model is applicable to comet 9p / tempel 1 ( hereafter, t1 ), the target of nasa s deep impact ( di ) mission, because di excavated the t1 nucleus up to @xmath4@xmath5 m depth. in this review,   we discuss the results of recent observations of the ejecta plume produced by the di event and the existence of large compact dust in the pre - impact t1 coma that are consistent with the standard model.
diffuse radio emission from galaxy clusters is a rare phenomenon.   the origin of radio halos is believed to be the synchrotron radiation of relativistic electrons. in this paper, we investigate the evolution and number distribution of radio Halos with different lifetime scales. for each of the three typical lifetimes that are representatives of different origins for radio halo, we estimate the different number distributions and compare the results with observations to determine the valid models that are responsible for their origin. using the hierarchical model based on the formalism proposed by ks, we calculate the formation rates and the comoving number density ofRadio halos in galaxy clusters.. the results show that the formation rate ofradio halos varies with the time scale of the cosmological time ( i.e., @xmath0.1 gyr, 1 gyr or 1.5 gyr ) ; however, the number distribution depends on the lifetime of the galaxy cluster as well as the existence of the radio relics and the size of the cluster centers. considering the observed observations, we conclude that the most valid model for the source of radioHalos is the secondary electron model.
remote entanglement between distinguishable quantum memories may be used to establish a quantum repeater architecture for practical long - distance applications in quantum communication and quantum computation.   we analyze a generic protocol to establish remote entangler between a pair of distinguishable Quantum memories using a two - photon interference scheme. unlike single - photon interferometrically sensitive protocols,   two-photon interference schemes are not interferometric sensitive to the optical pathlength of the quantum memories, which may permit practical short - distance entanglements. here  , we apply this protocol to a few selected pairs of accessible pairs of quantum memories : two spectrally filtered atomic qu bits, two cavity - coupled solid - state qubits, and a single solid -State qubit and a one - atom qubit. while the fidelity of the protocol is evaluated through a general analysis of the two - photons interference, we show that it can be achieved with high fidelity and high fidelity for distinguishable sources, while maintaining an acceptable rate of entanlement.
we present fuzzy logic based algorithms for two basic problems in astronomical pipeline processing which are rejecting cosmic ray hits and converting celestial coordinates to image coordinates.   the first problem is to transform the topocentric celestial coordinates ( azimuth, altitude ) of a given location to a polar angle in the image from ( @xmath6 ) and the radial distance ( in pixels ) from (@x math6 ). in order to obtain the coordinates transformation,   we build a fuzzy logic model based on manually identified reference stars.the reasoning procedure is based on _ product _ inferencing and _ weighted average _ defuzzification, which is an efficient defuzzifying method when the fuzzy logic models are built according to a set of singleton values @xcite.    the algorithm has been implemented for the _ night sky live!_ @xcites project, which deploys 10 all - sky ccd images of the sky every 10 days.
self - propelled particles are artificial self - propelled objects that convert chemical, magnetic, or radiation energy into directed motion.   their propulsion mechanisms are manifold and reach from the beating of a single flagellum via twisting deformations of whole filamental bacterial bodies to the synchronization of the motion of thousands of cilia. in this review,   we present a new field - theoretical approach to the description of active crystalline systems of self - propelling objects based on the phase field crystal model @xcite and the toner - tu model. by taking into account the translational order of the migration directions of the self - propel particles  , we show that they can form active crystals that collectively migrate as a single structure. for the first time, we also show that these crystals can be classified into two main types : ( 1 ) localized and ( 2 ) multidomain structures that migrate in a single collective direction. when the local migration directions spontaneously order, long - ranged orientational orders of the global migration directions   are obtained, which are then used to describe the macroscopic emergence of collective motion.
we present time - optimal control algorithms for the synthesis of arbitrary unitary transformations on a coupled qubit system where local transformations on the first qubit take significantly less time than local transformations in the second one.   in addition, we assume that the coupling evolution is much slower than transformations on both qubits but much faster than transformations at the same time scale. using a canonical decomposition of @xmath0 in terms of the subgroup @x Math1 reflecting the significantly different time scales immanent in the system  , we derive time - efficient control algorithms to synthesize various unitary transforms. our methods are applicable to coupled electron - nuclear spin systems occurring in pulsed electron paramagnetic resonance experiments at high fields, where the rabi frequency of the electron is much larger than the hyperfine coupling.
the origin of the angular momentum in the dark halo is a key ingredient in the origin of galactic rotation, which can be studied in detail using high - resolution @xmath5-body simulations and analytic approximations.   we find that the mass distribution of specific angular momentum @x Math4 is well fit by a _ universal _ profile : m(<j)= m j /(j_0 + j ) , > 1 . for more than half the mass,   the profile is shaped by a power law, which flattens off if @x math15 is replaced by a robust spin parameter.. the spatial symmetry of @x maths4 tends to be more cylindrical than spherical ; in 80% of the halos, the mean value of @Xmath4 ( over longitude ) decreases by less than a factor of 2 when moving away from the equatorial plane along lines parallel to the spin axis. under the assumption of an isothermal halo with a flat rotation curve  , one can calculate the surface - density profile of the halo using an nfw profile, which self - consistently solves the angular - momentum problem.
the decay of @xmath10b by two - neutron emission in a magnetic field ( dimf ) and in a target ( dit ) is studied.   the decay energy of the decay in the target is calculated to be about 1  kev, which is consistent with a finite lifetime because of the small barrier which is only due to the angular momentum. for the decay of the ground state of@xmath7o @xcite,   an upper limit of 5.7  ns is obtained by assuming the survival of the decaying nucleus along the flight path in a magnetically induced magnetic field at a distance of 0.5  cm from the detector where the decay takes place.    the half - life sensitivities of the two methods are also discussed.
quasars have been thought to be spectroscopically similar in the early days of quasar research.   recent years have seen more attention given to spectral differences that may be related to the wide range of eddington ratio likely to be present in the quasar population now much better sampled via optical surveys ( bright quasar survey ( bqs ), hamburg - eso ( he ), sloan digital sky survey ( sdss ), etc. ; ). a landmark study of systematic trends in quasar spectra @xcite involved a principal component analysis ( pca ) of 87 bright quasarts from the palomar - green survey and was generalized into a 4d eigenvector 1 parameters ( 4de1 ) space which added measures of the soft x - ray photon index ( ) and broad line profile shift. here   we adopt the empirically motivated pop.. a and b subdivision involving fwhm ( ) @xmath4 4000 sources, which are, respectively, narrower and broader than the optplane. for each of these two populations we gridded the 4 de1 optical plane into bins of fw( ) and iron emission strength using the redward
the color - magnitude relation ( cmr ) between the luminosity of early - type galaxies and their rest - frame optical color is a well established feature of the universe.   the relation implies that the properties of the stellar populations in these galaxies are strongly dependent on the total stellar mass of the system. here   we extend the analysis of the cmr to a sample of nearly 20 million galaxies from the sloan digital sky survey ( sdss ), a large collection of data from the early data release of the sloa digital sky surveys ( sdrs ).    we find that the slope of thecmr is independent of galaxy environment and that the dispersion around the relationship is small, @xmath4 milli - mag ( mmag ) for clusters at a @x Math2.5 ; this scatter indicates that the age of the population of stars in these clusters must have been earlier than the observed epoch. using the same distribution of galaxies in the sdss, we show that the distributions of galaxy colors in the field are similar to those found in the mdss, with the exception of the cluster ms 1054 - 03, which has a larger dispersion in the red - sequence color @x
we use a family of simple models to explore the effects of infall, outflows, age differences and star formation laws ( sfls ) on the colour - based ages and metallicities of spiral galaxies.   we use the ages and metallicity of a sample of face - on spiral galaxies to constrain which processes are the most important in affecting their observational properties. using a closed box model, we show that the galaxy formation epochs of two different types of chemical evolution models are strongly correlated with each other, and with galaxy parameters, such as surface brightness and magnitude. by comparing the results of these models with those of observational data, we find that the behaviour of the closed box models is more closely related to the observed trends in galaxy formation than to any of the other models.. however, the results also show that changing the sfl does not affect the results : the effect of changing the number of stars in the galaxy can be explained by a local density - dependent sfl, and by a galaxy mass - dependent chemically - enriched gas outflow.
the adsorption and dissociation of o@xmath0 molecules on metal surfaces are of great importance to the subsequent oxidation reactions and to the formation of metal oxides @xcite.   the theoretical _ ab initio _ modeling based on the adiabatic approximation has been proved successful over a wide range for studying the adsorbed and dissociations of o=x Math0 on transition metal surfaces, but the experimental results are still controversial. in this paper  , we investigate the oxygen dissociation process at the pb(111 ) surface using density functional theory ( dft ) calculations. by comparing the results obtained from the dft calculations with those obtained from experiments,   we find that there are no significant differences in the initial sticking probability of thermal o&o@x math0 molecules at the al(111) surface between the two surfaces.. however, the initial stick probability of molecular o@Xmath0 adsorptions at the bp(111)-surface is significantly lower than that at the be(0001 ) surface, which is due to the presence of nonadiabatic effects on the bond energy of the o+/o bonds during the adsorbation process.
we investigate the hemispherical power asymmetry in the cosmic microwave background ( cmb ) temperature and polarization anisotropies measured by the wmap satellite in its first - year observation.   we use the quadratic maximum likelihood ( qml ) method to estimate the angular power spectra of the cmb signal on 24 pairs of hemispheres defined by galactic coordinates @xmath0 and@xmath1 $. for each of those, we find that the asymmetry is present at large angular scales, with the magnitude of the effect strongly dependent on the choice of the parameter @x Math4.. the results are confirmed by monte carlo simulations using wmap 7-year low - resolution data.
we report the identification of a new, transient high - mass x - ray binary ( hmxb ) pulsar from the galactic plane in 2004 july - august.   the source is a bright, long - period variable star that is only @xmath13 from the X - ray source and has been observed by the _ rossi x -ray timing explorer_ ( _ rxte _ ; *??????   * ) proportional counter array in the galaxy plane. using photometry and spectroscopy, we show that it is a reddened counterpart of the previously identified hmzb.
accretion - powered millisecond pulsars have been discovered with spin periods between 1.7 and 5.4ms.   the accretion disc is usually located outside of the co - rotation radius of the neutron star, where it is surrounded by a dense layer of gas pressure and free - free opacity. in this paper   we extend our previous study ( paper i ) of an accretion disk with an internal dynamo around a magnetised star to the discs around milliseconde pulsars. due to the weak magnetic field of the companion star, the disc extends to much smaller radii, at which it becomes so hot that a significant part of the opacity is due to electron scattering, and radiation pressure can grow stronger than the gas pressure. for each of these systems we derive a single ordinary differential equation, which is generally applicable for the radial structure of the accreted disc independently of the magnetic dipole moments of the orbiting neutron star. using the differential equation we show that the rate of accretion of matter into the disc increases by more than an order of magnitude when the alfvn radius is only slightly larger than the co-rotation radius, and that the density of the jets that are accelerated away
the development of custom - designed fee for specific applications has become very demanding in terms of costs and resources.   the proposed fee was developed to meet the challenging requirements of an imaging cherenkov counter, the barrel dirc ( detection of internally reflected cherenovov light )  @xcite of the panda experiment. a modular design with a preamplifier add - on card allows the realization of versatile fee that can be used for different types of readout. as a test case  , we demonstrate the implementation of a new fee based on the nino application - specific integrated circuit ( asic ) for the photodetector readout of the future neutron detector ( ndet ) of the a1 collaboration.
max - stable processes are the only possible non - degenerate limits for rescaled pointwise maxima of random processes, thus motivating their use in modeling spatial extremes.   flexible max - stable models have been developed for inference on spatial extremes using gaussian processes and their dependence structure is determined by a variogram, so well - established ideas from classical geostatistics may be exported to the extremal context. over a variety of applications,   the brown  resnick process has proven to be a valuable model for extremes of environmental variables, such as rainfall, temperature, wind speed and river discharge. here   we propose a bayesian hierarchical model for fitting max -stable processes based on a special case for which the full likelihood of such a process can be calculated, using the joint distribution of componentwise Maxima and their partitions in terms of individual events.    we discuss the difficulties of using the partitions in practice, and propose a new bayesian approach to fitting max-stabilized processes without fixed partitions.
we propose a new, generalized conservation law for the main - chain polymer nematics that consistently incorporates both the vectorial as well as the tensorial conservation laws.   we show that the two conservation laws are not equivalent, are irreducible and in general lead to different consequences specifically stemming from the presence of the backfolding configurations of the polymer chains, or in an extreme case, to localized hairpins and/or kinks which should be in particular relevant in the description of confined dna mesophases, where such local defects or elastic energy non - linearities have been implicated recently.
we explore the possibility of radiative electroweak symmetry breaking ( ewsb ) in non - supersymmetric ( non - susy ) extensions of the standard model ( sm ), where the positive mass parameter of the higgs boson at high energy becomes negative at low energy due to the renormalization group flow which dictates how the parameters evolve with scale.   we argue that this mechanism may be necessary in certain classes of grand unified theories ( guts ) which have two stages of symmetry breaking. for these models,   the first stage is symmetries breaking and the second stage is electroweak asymmetry breaking by generating neutrino masses as loop corrections from the strong scalar triplet with a small induced vacuum expectation value ( vev ) or weak scalar singlet with a very small vev. in the latter stage, the gauge symmetry is broken by a single sm singlet component which acquires a large vev breaking the symmetry down to sm. in both stages, the positive squared mass of the hgbs boson should turn negative but in the case of the former it should remain positive. using x - ray diffraction data from the cms and atlas experiments, we show that
we take the lennard - jones model to describe the state of could quark matter in quark stars   @xcite, and present the parameter space which can be allowed by pulsars with mass higher than @xmath0.   we find that if the number of quarks in one quark - cluster @x Math7 satisfies @x math8, then there is enough parameter space for the existence of quark star with masses to be higher than@x maths0. under some reasonable parameters,   the maximum mass could be higher as high as 2 @xMath4. the results are consistent with the constraint imposed by non - atomic spectrum of pulsars.
the vibrational energy relaxation ( ver ) process of the amide i mode of n - methylacetamide ( nma ) in vacuum is investigated by directly solving the schrdinger equation for molecular vibrations on the _ ab initio _ potential energy surface.   the vibrational configuration - interaction ( vci ) method is used to calculate the quantum dynamics of the nma molecule, excluding the 6 lowest - lying modes including the rotational motions of the two methyl groups. using a fourth - order taylor series expansion around the equilibrium geometry, which is called quartic force field ( qff ),   24 vibrational modes are explicitly treated in the dynamics, excluding those that are not included in the previous studies @xcite. from the results of the vci calculations, we propose a time - dependent perturbation theory to describe the ver process of nma and its vibrational self - consistent field ( vscf ) calculation.
the nasa / stanford spaceborne mission gravity probe  b ( ) was designed to measure the kinematics of objects in the vicinity of a near - earth inertial frame relative to the distant universe using the radio technique of very long baseline interferometry ( vlbi ) of a quasar relative to another quasar nearby on the sky.   we describe the astronomical effort undertaken with the guide star, i m pegasi, for the support of the  mission, vlmi for gravity probe b, " in seven papers published in the last two decades. here  we give a synopsis of these papers.
quantum resonances of the well - studied kicked rotor ( kr ) @xcite have been known theoretically for some time, but the first traces of this example of frequency - matched driving have only recently come to light in experiments with cold atoms.   we report experimental data which show the behavior of a typical experimental ensemble of cold atoms under resonant driving and verify a recently derived single - parameter scaling law of the resonant peak seen when scanning the energy vs. the kicking period @xicite. from this data, we extract the previously derived scaling law and show that the effect of the quasi - momentum on the motion disappears in the classical limit of the kicked rotor, when the kick period approaches zero.
we present a new model of the minimal supersymmetric standard model ( sm ) of particle physics ( mssm ) with an extra @xmath3 in the gauge group of the standard model.   the model is based on the existence of two new contributions in this model : one coming from the superpartner of the stckelberg boson ( stckelino ) and the other from the quantum partner of the gauge boson mediating the extra@xmath0. by taking some simplifying and reasonable assumptions on the fermion masses entering the soft supersymmetry breaking lagrangian  , we show that the lsp ( extra weakly interacting massive particle ) is interacting with the mssms particles with a coupling suppressed by the inverse of the mass of the extra gauge bosons of the theory which must be at least of the order of the tev for phenomenological reasons. to do this we have modified the darksusy @xcite package to keep in account the new interactions typical of our model and solve numerically the boltzmann equation for the most general case in which the extra msss sector is not decoupled to the Mssm sector and
recently, @xcite reported on the use of astrometry of asteroids to investigate gravity in the outer solar system and the potential use of such observations to ascertain the reality of the pioneer effect, an unexplained acceleration towards the sun that perturbs the motion of pioneer 10 and 11 beyond a distance of 20 au.   this paper shows that, contrary to recent assertions in the literature, the current ephemeris for pluto does not preclude the existence of the pioneers effect. instead, we show that the orbit of pluto is currently not well enough characterized to make such an assertion.
the entanglement entropy ( ee ) of a disordered cayley tree ( ct ) is investigated.   the ct is a simple connected undirected graph, with no closed loops. in this paper   we calculate the ee for a clean ct using the von - neumann entropy of the reduced density matrix, @xmath0, of the region a of the root of the tree, where the boundary area is proportional to the number of vertexes in the tree and the coordination number of each vertexes. as a stepping stone towards investigating the behavior of the eo for a disorderly ct, we find that the ea for the whole system is constant for the first generation, but grows logarithmically for the second generation, and then saturates for the third generation. for the fourth generation,   both the scaling and the saturation are dependent on the size of the boundaries of the regions. for all the remaining generations, the eae are constant.
we study numerically the statistical properties of landauer transmission and eigenstates as a function of the disorder strength @xmath0 and of the number@xmath1 of generations for the anderson tight binding model on the cayley tree.   we find that several probability distributions propagate as traveling waves with a fixed shape, as the number of tree generations grows. in particular, the traveling waves appear in disordered models defined on trees where it is the tail of the probability distribution that determines the velocity. from this traveling wave point of view  , the localization / delocalization anderson transition thus represents a traveling / non - traveling critical point.
we perform a comprehensive theoretical analysis of qubit dynamics under strong resonant pulses using floquet theory.   we derive approximate analytical expressions for the quasienergies and floquet states as functions of the driving amplitude for the practically important case where the qubit is biased at its symmetry point. in this case,   the quantum state of the qu bit is naturally expressed as a superposition of Floquet states. when the driving strength is fixed, the occupation probabilities of the floquetstates remain fixed as long as the driving strengths are small, but they can change when the pulse envelope varies in time. with suitable pulse parameters, the nonadiabatic transitions between the two energy eigenstates   can be largely suppressed, providing the basis of floquet interference efficient suppression of transitions in the adiabatic basis ( fiesta ), a method to optimize quantum gates with strong driving. finally, we show that fiesta can be used to implement high - fidelity single - qubit operations in very short times, significantly alleviating the effect of decoherence.
the computing requirements for high energy physics projects like the large hadron collider ( lhc ) at the european laboratory for particle physics ( cern ) in geneva, switzerland are larger than can be met with resources deployed in a single computing center.   this has led to the construction of a global distributed computing system known as the worldwide l hc computing grid ( wlcg ), which brings together resources from nearly 160 computer centers in 35 countries. to achieve this and other results the cms experiment, for example, typically used during 2012 a processing capacity between 80,000 and 100,000 x86 - 64 cores from the wLCg.. further discoveries are possible in the next decade as the lhC moves to its design energy and increases the machine luminosity.    however, increases in dataset sizes by 2 - 3 orders of magnitude ( and commensurate processing capacity ) will eventually be required to realize the full potential of this scientific instrument. ’ the scale and longevity of the Lhc computing require continual r&d into new technologies which may be relevant in the coming years. in this paper we report on our investigations into one such technology, low power arm processors
the ages and metallicities of stars in the spheroids of nearby galaxies provide some of the most important observational clues to the formation and earliest evolution of galaxies.   the halo stars of the milky way and the globular star clusters of m31 have been studied extensively, and the results suggest that they are mostly old, with ages between 11 and 13  gyr for the inner and outer halo's components, and between 10 and 15  g yr for the globulae of the galaxy's globular cluster ( cmd ). here  , we summarize what is currently known about the ages and metals of stars at radii of 8 - 33  kpc from the spheroid of ngc  5128 at @xmath14  k pc, which has a largely metal - rich population composed of @xmath13.3 + stars.
we are studying the main technical requirements to construct optical quantum computer ( oqc ) and comparing with solid - state quantum computers ( ssqc ).   the most prospective technique to construct quantum computer among them is s sqc. in this article  , we are proposing to construct oqcs based on rds crystals which are used for the construction of ion - trap quantum computer. as an example   we are taking one molecule having two atoms and each atom having nuclear spin @xmath2 and resonance frequencies @x Math3 and @x math4.    the two spins are interacting with each other with hyperfine interaction.. the quantum algorithms can be executed on quantum computer with the combination of quantum logical gates not and cnot ( control - not ). here, we will demonstrate the graphical representation of ssqC and how to perform logical operations on it.
the existence of absolutely continuous invariant probability measures ( _ acip _ s ) for maps with critical points and singularities is a problem which is still not completely solved even in the one - dimensional setting.   we formulate a condition which simultaneously keeps track of the growth of the derivative along critical orbits and of the recurrence of such orbits to the critical set within a single summability condition, thereby optimizing the result to include a larger class of maps than would be possible by having to independent conditions both of which need to be satisfied. using this condition, we show that it is not possible to obtain a general result on the existence of acip s in the presence of both critical points as well as singularities by assuming only conditions on the derivative growth of critical points.
we present a new software package for the analysis of atomic detail molecular vibrations @xcite.   the software reads a hessian matrix of force constants, constructs and diagonalises the dynamical matrix for any k - vector and calculates neutron and x - ray scattering observables using the gamma point analysis ( nma ) code phonon@xcite which is based on the explicit knowledge of the interaction between all atom - pairs in the system. to obtain the frequencies of the normal modes, the software constructs and diagonally diagonalises its dynamical matrices for each k-voltage and calculates the frequency distributions of the corresponding vibrational modes. as an example  , we demonstrate the application of the software to the study of internal molecular vibrations in the lattice vibration problem of crystalline materials.
the properties of magnetic fields in cooling core clusters of galaxies have been studied in high - resolution by studying the faraday rotation of electromagnetic waves from polarized radio sources.   the results show that the strength of the magnetic field is strongly correlated with the temperature profile of the cluster, and that the outer regions of the clusters are more susceptible to a conduction - driven  magneto - thermal instability  ( mti ) that re - orientates the lines of magnetic field to be preferentially radial, resulting in a thermal conduction at a high fraction of the spitzer conductivity. however, the centers of cooling - core galaxy clusters are characterized by a sister heat - flux buoyancy instability ( hbi ) that arises in regions where temperature increases with radius. here  , we investigate the effects of these two instabilities on the thermodynamics of the interstellar medium ( icm ) plasma in a 3-d model of an isolated cooling core galaxy cluster, @xcite, and find that they are both associated with a pair of _ overstabilities  that affect precisely those configurations that are stable to the well - established hbi and mti. for the first time, we find that the stability of the hbi
josephson effects occur when two extended superconducting banks are weakly coupled and can be observed, among many other systems, across a geometric constriction of a superconductor with lateral dimensions much smaller than the coherence length.   this kind of junction, usually referred to as scs junction, has promising properties for highly sensitive magnetometers. in the present paper  , we examine a two - dimensional model of a scs junctions in order to investigate the dependence of the dc josephalic effect on temperature, on geometric parameters as well as the influence of magnetic fields, external ones as wellas those generated by the supercurrents flowing in the junction. using microscopic eilenberger theory, we numerically solve the relevant equations self - consistently for a conventional ( s - wave )superconducting junction in the clean limit. in orderto achieve electromagnetic self - consistency as well,   we employ a convenient method to calculate the magnetic field evoked by the Supercurrents.    this will allow us to derive transport properties for a realistic geometry at arbitrary temperature and arbitrary external magnetic field.. furthermore, the method used to solve microscopic eilevenberger theory self - consistent including magnetic
the notion of geometrical entropy arises in statistical mechanics.   it is a function which depends on a macroscopic state of the system and gives the ( logarithm of the ) number of different microscopic states corresponding to this macro - state. in this paper   we try to implement the idea of geometric entropy following a very simple choice of the ` ensemble'of quantum states, and we find that for any geometry configuration all quantum states approximating a riemannian metric can be considered as micro - states. by taking into account the space of states of a system with respect to the gravitational degrees of freedom of an arbitrarily chosen in space 2-dimensional surface, we show that the entropy of a macro -state of our system is given by the logarity of the volume of the compartment corresponding to the same macro -State. here   some of our results are surprising, but the aim of this paper is not to argue a physical significance of the results obtained. instead, we consider a particularly simple case, in which the analysis can be accomplished, and develop a technique that may prove useful for future developments.
narrow line seyfert 1 galaxies ( nls1 ) are a special class of active galactic nuclei with narrow emission lines.   the steepness of the soft x - ray spectra frequently correlates with the narrowness of the optical lines hinting for a connection of this class with soft state galactic sources. in the present paper   we reanalyze the high resolution data of ton s180 ( @xmath0, corresponding to 286 mpc for hubble constant 65 km s@x math1 mpc@xmath1 ), an extreme case of a nls-1 with its low value of the fwhm of @x Math2 line. using a new response matrix acisleg1d1999-07-22rmfn0002.fits and including any effects related to the contamination layer on acis - s.  , we detect several weak narrow absorption lines due to the material located at the line of sight to the source. also, several individual disk lines are fitted with equivalent widths in rough agreement with the predictions of the model of illuminated accretion disk spectrum presented by raska et al. in sec.  for fitting absorption by warm,
scalar fields have been widely studied in the field of cosmology since the early time accelerated expansion of the universe.   their role in this process has been extensively studied in terms of their contribution to the initial fluctuations in the universe and their potential to explain the late time acceleration observed in the cosmic microwave background radiation ( cmbr ) and galaxy clustering by large scale redshift surveys. here  , we review the recent advances in the study of scalar field models describing spin-0 particles in the relativistic theory of gravitation and discuss their potential role in solving some of the outstanding issues in cosmology.
in this paper, we review the effective loop quantum cosmology ( lqc ) theory and study the effect of quantum correction on the luminosity - redshift relation of type ia supernovae ( snia ).   we use a massless scalar field model to model the dark matter / energy, and derive the classical luminosity-redshift relation for this model. in secs. and , we study the quantum effects of the quantum correction scheme in the holonomy corrections, paying much attention to the @xmath0-parameter in the@xmath1 scheme. using the gedanken experiment, we test the different behaviors of different quantum gravity schemes, including the string theory and the non - perturbative quantum gravity, which have been causing ambiguity in the current state of the art.
the tunka eas cerenkov array has been used to measure the depth of the atmosphere at the energy of the knee.   the experiments have been calibrated with the quest experiment at the eas - top array, a high - altitude atomic force microscopy ( afm ) experiment in tunga valley, brazil. for the range from @xmath7 to@xmath5 ev, the new fitting function ( ldf ) for the lateral distribution of the cherenkov light has been applied to the data and the absolute energy calibration is based on the results obtained with the quests experiment. according to these data, the mass composition of the primary particles has almost no energy dependence in the range between @x Math5 to @xMath18 ev. at energies above @x maths18 ev, however, a steep increase of the average mass is observed.
the present paper presents simple analytical formulas for the identification of the jump part of a long - term variable ( lvy ) process.   the first group of results are formulas for @xmath0, or time decay, of out - of - the - money european call and put options on a stock, at expiry. by using these formulas and empirical data for options near expiry as in carr and wu ( 2003 )  , it is possible to identify the jump component of a particular lvy model. after that, by using the data forOptions far from expiry, one can identify the first instantaneous moment of the process, and calculate the diffusion coefficient by subtracting the second instantaneous moment.the results are explicit analytical expressions in terms of the parameters which characterize the process. by use of the formulas for each of the above parameters,   it is shown that the coefficients of the diffusion component are linear functions of time to expiry ; the latter is shown to be negative if there are positive ( resp., negative ) jumps.the generalizations to mean - reverting processes driven by lvy processes ( the ornstein - uhlenbeck type processes ), stochastic volatility models with
we assess the feasibility of using lossy photon - number - resolving detectors ( pnrds ) for measuring quantum correlations under joint photodetection in the presence of saturation.   the variance of difference of photocounts ( vdp ), which has been shown to be a good measure of entanglement, is used as a parameter for the calibration of the positive - operator valued measure ( povm ) model of the photon -Number - resolving detector ( pnsrd ). here  , we show that the vdp can be used to estimate the quantum correlations between two states of light with poissonian statistics by comparing the first and second moments of the photocounting of the same state with the first moment of the pov m for a state with poisonian statistics, and the effects of saturation on the calibration protocol are discussed.
we present a multirate method for integrating systems of ordinary differential equations ( odes ) which arise from step models describing nanostructure evolution.   the strength of our method, in comparison to other existing multirates, is its order of accuracy : our method is fourth order provided solutions are sufficiently smooth. we demonstrate our method by using a fourth order runge - kutta method ( with error control ) for the inner and outer schemes and coupling them together with cubic interpolants.
we have started a program to search for multiplicity among low- and intermediate - mass protostars ( class0 and i ) using the owens valley radio observatory ( ovro ) millimeter array.   our program aims at sub - arcsecond resolution corresponding to linear resolutions of 150 to 450au. in the first phase, we trace the optically thin thermal dust emission from cb230, a bok globule located at a distance of @xmath0450pc, which contains a strong submm / mm continuum source and a dense cs core which shows spectroscopic signature of mass infall. with the 1 mm and 3 mm continuum maps  , we show that the central part of the dense core has a core - envelope structure and peaks at the origin of the western bipolar nir nebula near the pre - main sequence binary separation distribution peak. by using the 1.2 mm continuum and molecular line lines, we also demonstrate that the outermost part of this core is well - collimated and can be seen as a bright northern lobe perfectly aligned with the blue lobe of a well -collimated co outflow.    the results are consistent with the theory that binary systems form during the gravitational
the most predictive grand unified theory based on an @xmath0 gauge symmetry is a minimal non - supersymmetric model of georgi and glashow   @xcite ( gg ).   however, the failure to accommodate experimentally observed fermion masses and mixing and to unify electroweak and strong forces decisively rule it out. in this paper   we present a truly minimal, i.e., minimal in terms of number of fields, realistic non - superparametric @x math0 scenario. as a consequence  , we investigate all relevant experimental signatures of the scenario, including its status with respect to the present bounds on nucleon lifetime measurements. for this purpose we define our framework and show that it is possible to get gauge couplings unification in agreement with low energy data by adding only one or two gauge couples to the gg model. at the same time, we demonstrate that the existence of light scalar leptoquarks in the minimal scenario generates novel proton decay contributions which can be used to generate very rich phenomenological signatures. since in our scheme their coupling to matter is through the majorana neutrino yukawas, their observation might even
catalan numbers are ubiquitous in the modern mathematical literature.   they have a rich history of discovery, from their first discovery by leonhard euler ( 1751 ) to their recent rediscovery by luo jianjin ( 1988 ) and the work of johann segner ( 1839 ). here   we review the history of catalan numbers over 200 years, starting with their discovery by euler in 1751 and ending with their re - discovery by goldbach in 1759. while many of the early discoveries were based on the use of binomial equations, some of the more recent developments involved the development of new methods for solving quadratic equations using the binomial formula.
planets that transit their stars offer us the opportunity to study the physics of planetary atmospheres and interiors, which may help constrain theories of planet formation.   currently, it is not feasible to find long - period, transiting planets from the ground. because of its long mission lifetime, nearly continuous observations, and large number of target stars, the _ kepler _ satellite @xcite has a unique opportunity to discover long - time transiting systems. in this article  , we show that planets with periods longer than the mission lifetime will likely be detected and can be characterized using the photometric light curve and precise radial velocity observations. furthermore, this technique can be applied to planets that will transit more than once during the _kepler _ mission, so that targeted increases in the time - sampling rate can be made at the times of subsequent transits.
we have entered in a new era of high precision cosmology and it is clear by primordial nucleosynthesis constraints and by the results from the power spectrum of the cmb produced by the 7-years data of wmap satellite that our universe is composed of dark energy ( de ), non - baryonic dark matter ( dm ) and for only @xmath3 by baryons.   however, it is not known where and in which form they are hidden and there are many reasons to believe that a non - negligible amount of them are in galactic halos or even in the galactic disk. here   we review some of the evidence for the existence of extra - planar gas around galaxies and we discuss the role of this gas in the origin of our galaxy.
we carry out large - eddy cosmological simulations by tracking the evolution beyond the formation of the first clump in minihaloes where cooling is regulated by molecular hydrogen.   we employ a fixed jeans resolution of 64 cells per jeans length throughout the evolution of the simulations and follow the collapse down to the scale of 0.1 au for 40 years using the adaptive mesh technique using the grid code enzo ( enzo = enzo, wmap seven years data @xcite ) with a subgrid - scale ( sgs ) model which takes into account unresolved turbulence. at the beginning of the simulation,   the initial conditions are generated from gaussian random fields at @xmath5 with a grid resolution of@xmath6 cells and the size of the comoving periodic box is 300 kpc. during the course of the refinement, an additional 26 dynamical refinement levels are employed in the central comoving 26.7 kpc of the halo, giving a resolution of sub au scales ( in physical units ). as a result, we observe that the fragmentation of the protostellar disk into multiple clumps occurs at the end of the second stage of the collapse, which leads to the formation
measurements of the masses and radii of neutron stars provide unique information on the equation of state of matter at densities above the nuclear saturation density.   the rossi x - ray timing explorer ( rxte ), which has provided more than 15 years of observations of bursts, has made it possible to not only make neutron star mass and radius measurements using observations of specific systems but also to quantify the systematic uncertainties in these measurements. in this paper  , we focus on a third possible source of systematic uncertainty, which is the absolute flux calibration of the proportional counter array ( pca ) on board Rxte. for sources from which a large number of bursts are observed,   systematically uncertainties in the determination of the eddington flux are at the 5%@xmath010% level. by contrast, for sources with well known intrinsic spectra, the errors in the spectroscopic determination of neutron - star radii due to systematic effects in the cooling tails of X - ray bursts are in the range of @xmath23%@Xmath08%. in order to better understand the factors that affect the accuracy of the measurement of both the apparent radii and the ed dington flux,
we examine the globular cluster luminosity functions ( gclfs ) of two brightest ellipticals which may be members of the coma i cloud.   both galaxies contain a kinematically  distinct core which may have resulted from a merger. using _ hubble space telescope _ wide field and planetary camera 2 ( wfpc2 ) data of forbes ( 1996 ), we can probe the gclf in these galaxies to about 2 magnitudes beyond the turnover magnitude. for each galaxy, we find that the fraction of detected globular clusters ( gcs ) with magnitude is similar for all four central compact disc galaxies ( ccds ). for ngc 4278,   the proportion of detected gcs with magnitude decreases with increasing gc metallicity, but does not change with increasing galaxy hubble type or galaxy environment. by comparing the distance modulus of the g clfs in ngc4278 and ngc488, we show that the distance determined by the gClf is in good agreement with other distance methods for galaxies in the same group.
we study a variant of the dueling bandits problem in which we offer pairs of items to a user and record implicit feedback on which offered item is preferred, seeking to learn the user s preferences over items quickly, while also ensuring that the fraction of time we fail to offer a high - quality item in our offered assortment is small.   we model regret as depending on the utility to the user of the best offered item, and show that an algorithm _ comparing the best  ( ctb ) has excellent performance in terms of regret, but its computational demands grow with the number of arms. for problems with many arms, we propose a more computationally tractable variant  scalable - ctB  ( sctb )  that can work well in high dimension with a large number of arm, and prove that both algorithms have constant expected cumulative regret. using simulated and real datasets, we demonstrate through numerical experiments that they significantly outperform existing algorithms.
experimental level densities in the quasi - continuum of atomic nuclei represent an important test ground for nuclear structure models.   they contain information on the average distance between single - particle energy levels, the size of shell gaps and residual interactions like the pairing force between nucleons in time - reversed orbitals. in this work   we study how the level density at shell gaps is affected by the low single - particles level density, both as function of neutron number and excitation energy. using the oslo method @xcite, we report on the level densites below the neutron separation energy for the @xmath10y isotopes with neutron number@xmath5 and 51, respectively.    the experimental results are compared with a simple combinatorial model from which additional information on parity and spin distribution can be obtained.
we re - examine the @xmath7 relation of willott et al.   ( 1999 ) for the kinetic power of active galactic nucleus ( agn ) jets using a new method based on measured properties of jet termination shocks known as hotspots. in this work, we show that the conversion of radio luminosity to jet power is sensitive to the size of the agn radio lobes, largely due to inverse compton losses. by taking into account these losses,   we find that the slope and normalisation of the@x math7 relation are dependent on the distribution of source sizes within the sample being considered. when the model is fitted to the observed data, the results are in good agreement with the concordance cosmology of @x Math9, but the latter is not always the case when the data are taken from a dynamical model of the radio source.
tree level gauge mediation ( tgm ) is a new scheme for the communication of supersymmetry breaking in a hidden sector with no renormalizable interactions with the observable sector.   it is based on the renormalisable exchange of heavy vector superfields at the tree level, where the action of the gauge generators on the full set of chiral superfields is traceless and the supertrace of the squared masses of the quantum numbers of the standard model ( sm ) fermions and their supersymmetric partners, the sfermions, is modeled by the model - independent effective lagrangian operator @xcite. here   we show that tgm can be used to communicate spontaneously broken supersymmetrized theory from the hidden sector to the observable one via the exchange of superheavy vector field superfields. as a proof of our results, we consider the case of the monte carlo model of the mssm and show that this approach is able to reproduce the experimental results.
the left - right ( lr ) symmetric model @xcite is an attractive extension of the standard model ( sm ).   the symmetry requires the introduction of right - handed partners for the observed gauge bosons and neutrinos, and a higgs sector containing one bi - doublet @xmath4 ( 2,2,0 ), one left - handed triplet@xmath5 ( 3,1,2 ) and one right -handed triplet @Xmath6 ( 1,3,2).in such a minimal lr symmetric models, parity is an exact symmetry of the theory at high energy scale, and is broken spontaneously at low energy scale due to the asymmetric vacuum. in this paper, we analyze the spontaneous cp violation ( scpv ) scenario of the generalized two higgs bi-doublets model @xaite.    we find that the fcnc higgs boson s yukawa couplings are absolutely free parameters. therefore, low energy bound on the right - handsided scale is largely alleviated. as other generalized models, the two hi - doublets version of lr model also has the advantage to realize the sc pv without the fine -
quantum key distribution ( qkd ) establishes cryptographic keys between two distant parties in a way that is cryptanalytically unbreakable.   the canadian space agency has studied the proposed quantum encryption and science satellite ( qeyssat )   @xcite concept, which proposes a quantum uplink, which places the quantum receiver on the satellite while keeping the quantum source at the ground station. here   we present the first demonstration of qKd to a receiver on a moving aircraft.    our apparatuses incorporate coarse- and fine - pointing systems necessary to establish and maintain optical links, quantum source and measurement components that conduct polarization - encoded qkD, and suitable post - processing algorithms to extract secure key.. the results show good performance at the same angular rates exhibited by low - earth - orbit satellites, and demonstrate the feasibility and technological readiness of an uplink qk d satellite.
maxwel introduced, in 1871, a notorious being, known as maxwell s demon, to discuss the " limitations of the second law of thermodynamics" @xcite.   such a demon distinguishes the velocities of the gas particles and controls a tiny door on a partition of a gas container to create a temperature difference, which breaks the clausius statement of theSecond Law of Thermodynamics ( slot ). with the help of the demon,   the heat engine can absorb heat from a single heat resource and convert it into work without evoking any other changes in the cycle. in the present paper, we establish an optimal scheme of the thermodynamic cycle with a reversible erasure process, assisted by demon. for the single - particle heat engine, this is done by using a multi - particle working substance, which is the ideal bose or fermi gases, and find that the ratio of the work extracted to the working temperature has some discontinuous behavior, and that discontinuous behaviors are closely related to the degenerate - ground - state phenomenon. for quantum heat engines, the optimal expansion position to improve the efficiency of the single particle she to the carnot cycle s efficiency is found
we propose a linear threshold agent - based model ( abm ) for the spread of political revolutions on social networks in dictatorial regimes.   transitions from an inactive to an active state are governed by a growth process that uses a traditional linear threshold mechanism : an individual may change from the inactive to the active state if the fraction of neighbours in the active states exceeds the linear threshold @xmath2. here  , we derive a hierarchy of simplified ordinary differential - equation models of varying degree of sophistication that characterize the solutions of our linear threshold abm and show that these models perform remarkably well to predict qualitative behaviour of the abm.
the modeling and fitting application, _ sherpa _, is a new version of the _ chandra interactive analysis of observations ( ciao ) software package,@xcite, which is designed to tackle complex multi - dimensional, multi - wavelength analyses.   it is free of hard - wired instrument details, is outfitted with a wide variety of models, fit statistics, and methods of optimization, model comparison, and parameter estimation, and it offers powerful embedded visualization, scripting, and data manipulation capabilities. in this paper   we present a basic overview of the application itself, while we describe its capabilities using a typical session as a framework, from reading in data to determining the 1@xmath0 errors on the best - fit model parameters.
the mechanism by which energy is extracted from large - scale plasma flows and converted into heat is one of the fundamental problems in astrophysical magnetohydrodynamics.   the most accepted mechanism involves converting coronal magnetic energy into heat, where the magnetic field is assumed to be frozen into the plasma, so that the twisting and tangling of magnetic field lines by the photospheric footpoint motions eventually releases magnetic energy in the process of magnetic reconnection. in this work   we propose a new phenomenological treatment for the problem of coronal heating based on the volumetric parker model, where instead of prescribing the displacements of the footpoints, we impose a slow large -scale velocity throughout the entire volume of the fluid.. the heating rate is found to scale with the magnetic reynolds number @xmath0, and the time scale for the alfvn waves to propagate back and forth along the field lines through the system is determined by the rate of the thermal dissipation of the energy cascade toward small scales, which is independent of the reynold's number.
non - binary write - once - memory ( wom ) codes are getting renewed interests as one of promising coding techniques for storage media.   the non - binary wom codes are closely related to the multilevel flash memories and they are more suitable for practical implementation into storage devices. in this paper, we propose a novel construction of fixed rate non - binaries wom codes. using a general model of multileve flash memories with restricted state transitions,   it is shown that the proposed construction is able to determine the sets called the encoding regions that are required for encoding processes. by using a systematic method  , it determines an encode table used for encoding by integer programming.. the proposed code is applicable to a wide range of wom devises such as multilevally designed devices with inter - cell interference constraint.
the reweighted techniques are a group of path integral methods that have been developed to modify the random series representations of the feynman - ka formula by means of certain quadrature rules.   the purpose of the present article is to review the construction of two reweighed methods that are based upon the lvy - ciesielski and the wiener - fourier series, respectively. in order to preserve the asymptotic convergence of the reweighting techniques,   it is necessary to employ a quadrature technique which uses a number of quadratures points proportional to the number of path variables and which preserves the asylums of the results obtained from the formal convergence properties of the methods. for each of the two re weighed methods presented, numerical examples of the cubic convergence of these methods are presented.. the advantages of the use of such an approach are discussed.
the strong field approximation ( sfa ) is the widely used workhorse of strong - field physics.   however, the sfa is rather inaccurate for the case of long - range coulomb potentials due to the neglect of the interaction between the photoelectron and the parent ion after the time of ionization. within the trajectory - based sfa,   the matrix element for ionization is written as a coherent sum over ionization times for which the corresponding quantum orbits all lead to a given, final momentum @xmath0 at the detector. if there are more than one such orbit of similar weight, interference comes into play. in the current paper   we show that the sub - barrier coulomomb correction ( sub - cc ) can be used to correct the interference pattern observed in the classically allowed region of the sFA, i.e., from the so - called " tunnel exit" to the detector using the imaginary time method. in particular, the fringe shift in polarization direction caused by the sub-cc is investigated and discussed.
knotted proteins provide an ideal ground for examining how amino acid interactions ( which are local ) can favor their folding into a native state of non - trivial topology.   some of the mechanisms that can aid knot formation are investigated here by comparing coarse - grained folding simulations of two enzymes that are structurally similar, and yet have natively knotted and unknotted states, respectively. in folding simulations that exclusively promote the formation of native contacts, neither protein forms knots. when sequence - dependent non - native interactions between amino acids are introduced, one observes knotting events but only for the natively - knotted protein. to gain insight into such mechanisms as well as to highlight general physico - chemical mechanisms favoring knot formation, an increasing number of experimental and numerical studies of knotted proteins have been carried out @xcite. among them, the recent experimental results have clarified that native knots can form spontaneously and efficiently from anunknotted initial state.see research article http://www.biomedcentral.com/1471-2148/7/8/17
the first stars to form in the universe may be " dark stars," a new phase of stellar evolution in which the dark matter ( dm ) provides the power source for the star through dm annihilation.   we first reported on this work in a paper submitted to the arxiv in april 2007. when we presented this work at the first stars conference in santa fe soon after, many questions were raised, which we have addressed in the subsequent year. in this talk   i review the basic ideas as well as report on the followup work we performed over the past year.
we present the first theoretical analysis of the error distribution of weighted centroid localization ( wcl ) in cognitive radio ( cr ) networks.   the presented analytical framework models varying levels of shadowing, including both independent and correlated shadowing environments, and also takes inaccuracy of sensor node positioning into consideration. using this analysis in conjunction with numerical simulations we observe and quantify the robustness of wcl to variable channel conditions and node placements. as a simple modification that can improve wcl performance, we propose a distributed cluster - based implementation of @xcite.
the dynamical mean field theory approach ( dmft ) and its cluster generalizations@xcite have become some of the most powerful techniques to study strongly correlated electrons.   these methods are exact within statistical errors and, for the one - band hubbard model, certain versions @xcite at the single site level do not suffer from sign problem. yet, these approaches require sizeable computational resources and, in addition, real frequency information must be obtained through analytical continuation of data with statistical uncertainties, an ill - posed problem for many applications. here   we show that iterated perturbation theory ( ipt ) is unsatisfactory for a number of parameters close to half - filling for both @xmath10 and@xmath14 when the condition @x math4 is applied.    we propose a way to circumvent this problem by using the fact that when @x Math7 is large enough, the double occupancy becomes almost temperature independent in the paramagnetic state with a value that is, to a high degree of accuracy, a simple function of the density.. this provides us with a condition different from @x maths4 that allows one to close the ipt equations even for large coupling. 	 this
the ozpoz fibre positioner for the flames fibre - spectroscopy facility on the vlt ( http://www.eso.org/instruments/flames/ozpoz.html ) is being built by the australis consortium.   it will provide full access to the 25arcmin diameter ( 0.136deg@xmath0 ) field of view of the vtls nasmyth focus, and can handle up to 600 single - object fibres and multiple deployable fibre integral field units ( d - ifus ) in a single 24  arcsec diameter field. with the advent of new 8-metre telescopes,   the demand for multi - object spectrographs is so strong that every eight -metre observatory will have at least one. maximus aims to provide vlt users with the maximum multiplex advantage allowed by the ozpo zonular optical coherence tomography ( ozpoZot ) fibre positioners, for both unresolved single - fibres as well as small, deployable integral fields. here   we describe the development of a new instrument, maximus, which will use all four of the four field plates available for
the soft x  ray transients ( sxt ) of black hole binary systems give one of the most direct ways in which to study the physics of accretion disks.   many of these systems show dramatic outbursts where the luminosity rises rapidly from a very faint quiescentre to one which is close to the eddington limit, and then declines again over a period of months, giving a clear sequence of spectra as a function of mass accretion rate. here   we present a new model of the accretion flow that covers the whole range of luminosity seen in the sxt, and shows that it can reproduce the overall spectral evolution of the source.
the roussarie s finite cyclicity conjecture claims that every limit periodic set occurring in an analytic finite - parameter family of plane analytic vector fields, has a finite cycle.   the purpose of the present paper is to prove this conjecture for a two - saddle cycle of a polycycle of a plane polynomial vector field @xmath9-saddle cycle ( or a hyperbolic @x Math9-graphic ) composed of saddle - type singular points connected by separatrices and heteroclinic orbits. using a suitable version of the argument principle, we find a relation between the fixed points of the poincar first return map and the fixed point of holonomies of the separatrices of the saddle points, which correspond to complex limit cycles. as a result  , we show that the connected components of the zero locus of the imaginary part of a dulac map are smooth semianalytic curves, which allow to count the number of the zeros of the limit cycles of the family of families of _ analytic functions_. the results are compared with those of the previous work by cherkas, mourtada, el morsalani, dumortier, r
dense self - avoiding polymers in two dimensions ( 2d ) have been considered theoretically by means of computer simulation @xcite and more recently even in real experiments@xcite.   it is now generally accepted that these chains adopt compact and segregated conformations at high densities, i.e., the typical size of chains and subchains should scale as @xmath21 with a flory exponent set by the spatial dimension. here   we present here theoretical arguments and molecular dynamics simulations demonstrating that the contours of dense 2d polymers are in fact fractal, scaling as  for sufficiently long chains and as  for subchains. due to the generalized porod scattering of  compact  objects,   the structure factor of dense2d polymer chains should scale in the intermediate wave vector regime as for sufficiently short chains and _ not  for sufficiently large chains as numerous authors have assumed.
biological organisms have structure at many different levels of organization, from the scale of small molecules to genes, to chromosomes, to subcellular organelles in eukaryotes, the arrangement and differentiation of individual cells in multicellular organisms, and the organisms themselves in the context of ecology.   these objects are not inherent aspects of the matter that biological systems are made of, or directly arising from the underlying physical laws, but instead are a consequence of biological processes and the information stored within the system that encodes them. this information is discovered and sustained by self - organization of the biological system, via the processes of evolutionary dynamics. here   we review the recent work on the emergence of higher - level organization in biological systems, and discuss how this process can be used to understand the evolutionary history of life.
the aim of this paper is to present a new home security system that uses a combination of sensors and microprocessors to monitor the presence of trespassers and possible intruders in the home premises.   it also uses a wireless network to send an e - mail to the home owner with the video of the intruders or any activity occurring outside the door in case of a break - in. since all of this is done in real time, one does not have to scroll through long durations of time, often hours in order to get to the relevant section of the video from the microcontroller which is then stored locally. as a result,   the system can be integrated with already installed home automation systems without the need for additional hardware installations.
the giant radio galaxy m87 is a powerful accelerator of high energy particles, possibly even up to the highest energies @xcite.   this makes m87 an interesting candidate for tev @xmath1-ray emission. in 1998/1999 observations with the hegra stereoscopic telescope system ( h.e.s. )   it was found that m87 has a large jet angle between its plasma jets and the observer s line of sight which makes it different from the so far observed tev emitting active galactic nuclei ( agn ) which are of the blazar type with their plasma jets pointing directly towards the observer. to confirm the result and to further clarify the origin of the tev@x Math1-rays,   new observations have been performed with the h. e.s.-stereoscopic cherenkov telescopes operating in a coincident mode at a height of @x math15 above sea level in namibia. during the observation period from march 2003 to may 2004, the full four telescopes recorded a total of ~3,000 images of m87 with an average zenith angle of about @x maths18 for each event. after data calibration and application of image cleaning tail
short - lived radioisotopes ( slri ) have been found in chondritic refractory inclusions from the early solar system.   most of these nuclei have been produced by stellar nucleosynthesis, but there are also reports of local irradiation of the @xmath4be short - lived isotope in a presolar cloud core that collapsed to form the solar system and the presence of live@xmath17be in al - rich, refractary inclusions.    the goal of this paper is to continue the theoretical exploration of the trigggering and injection scenario for slris, in the context of shock waves striking a dense molecular cloud core with respect to the formation of the solar systems.. the results show that the @Xmath6al observed in the inclusions can be explained by an interstellar shock wave striking the core of the presolar Cloud, which would have been generated by a supernova or an agb star, and that the ~1.5  kcal / mol increase in the energy of the shock wave would have caused the collapse of the core, leading to the injection of the long - lived @x Math17be into the space - time continuum.
reed - solomon ( rs ) codes are one of the most popular error correction codes in many state - of - the - art communication and recording systems. in most of these existing systems,   rs codes are decoded via an algebraic hard decision decoding ( hdd ) algorithm. when soft information about the channel output is available, hdd can incur a significant performance loss compared to optimal soft decision decoding.   consequently, soft - input - soft - output ( siso ) decoding algorithms for rs code are of research interest both for theoretical and practical reasons. in this paper, we present an iterative siso decoding algorithm for rs codes that uses a sum product algorithm ( spa ) to adapt the parity check matrix at each iteration according to the bit reliabilities such that the unreliable bits correspond to a sparse submatrix and the spa is then applied to the adapted parity check matrices. by applying the adapted scheme to the rs codes, we show that the convergence behavior of the iterative decoder is much better than that of the hdd algorithm.
